Science.gov

Sample records for antixi particles

  1. Xi0 and anti-Xi0 Polarization Measurements at 800-GeV/c

    SciTech Connect

    Abouzaid, E.; Alavi-Harati, A.; Alexopoulos, T.; Arenton, M.; Barker, A.R.; Bellantoni, L.; Bellavance, A.; Blucher, E.; Bock, G.J.; Bright, S.; Cheu, E.; /Arizona U. /UCLA /Campinas State U. /Chicago U., EFI /Colorado U. /Elmhurst Coll. /Fermilab /Osaka U. /Rice U. /Sao Paulo U. /Virginia U.

    2006-08-01

    The polarization of {Xi}{sup 0} and {bar {Xi}}{sup 0} hyperons produced by 800 GeV/c protons on a BeO target at a fixed targeting angle of 4.8 mrad is measured by the KTeV experiment at Fermilab. The result of 9.7% for {Xi}{sup 0} polarization shows no significant energy dependence when compared to a result obtained at 400 GeV/c production energy and at twice the targeting angle. The polarization of the {Xi}{sup 0} is measured for the first time and found to be consistent with zero. They also examine the dependence of polarization on production p{sub t}.

  2. Particle separation

    DOEpatents

    Moosmuller, Hans [Reno, NV; Chakrabarty, Rajan K [Reno, NV; Arnott, W Patrick [Reno, NV

    2011-04-26

    Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

  3. Particle separation

    NASA Technical Reports Server (NTRS)

    Moosmuller, Hans (Inventor); Chakrabarty, Rajan K. (Inventor); Arnott, W. Patrick (Inventor)

    2011-01-01

    Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

  4. Particle generator

    DOEpatents

    Hess, Wayne P.; Joly, Alan G.; Gerrity, Daniel P.; Beck, Kenneth M.; Sushko, Peter V.; Shlyuger, Alexander L.

    2005-06-28

    Energy tunable solid state sources of neutral particles are described. In a disclosed embodiment, a halogen particle source includes a solid halide sample, a photon source positioned to deliver photons to a surface of the halide, and a collimating means positioned to accept a spatially defined plume of hyperthermal halogen particles emitted from the sample surface.

  5. Particle astrophysics

    NASA Technical Reports Server (NTRS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    1991-01-01

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  6. Particle astrophysics

    NASA Astrophysics Data System (ADS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  7. Particle separator

    DOEpatents

    Hendricks, Charles D.

    1990-01-01

    Method and apparatus (10) are provided for separating and classifying particles (48,50,56) by dispersing the particles within a fluid (52) that is upwardly flowing within a cone-shaped pipe (12) that has its large end (20) above its small end (18). Particles of similar size and shape (48,50) migrate to individual levels (A,B) within the flowing fluid. As the fluid is deflected by a plate (42) at the top end of the pipe (12), the smallest particles are collected on a shelf-like flange (40). Ever larger particles are collected as the flow rate of the fluid is increased. To prevent particle sticking on the walls (14) of the pipe (12), additional fluid is caused to flow into the pipe (12) through holes (68) that are specifically provided for that purpose. Sticking is further prevented by high frequency vibrators (70) that are positioned on the apparatus (10).

  8. Particle therapy

    SciTech Connect

    Raju, M.R.

    1993-09-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

  9. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)

    1989-01-01

    Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.

  10. Particle preconcentrator

    DOEpatents

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

    2000-01-01

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

  11. Particle preconcentrator

    SciTech Connect

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

    1998-12-29

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

  12. Particle preconcentrator

    SciTech Connect

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

    1998-01-01

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

  13. Particle preconcentrator

    SciTech Connect

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

    2005-09-20

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

  14. Particle preconcentrator

    SciTech Connect

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

    2000-07-11

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

  15. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor); Rembaum, Alan (Inventor); Richards, Gil F. (Inventor)

    1987-01-01

    Metal oxide containing polymers and particularly styrene, acrylic or protein polymers containing fine, magnetic iron oxide particles are formed by combining a NO.sub.2 -substituted polymer with an acid such as hydrochloric acid in the presence of metal, particularly iron particles. The iron is oxidized to fine, black Fe.sub.3 O.sub.4 particles which deposit selectively on the polymer particles. Nitrated polymers are formed by reacting functionally substituted, nitrated organic compounds such as trinitrobenzene sulfonate or dinitrofluoro benzene with a functionally coreactive polymer such as an amine modified acrylic polymer or a protein. Other transition metals such as cobalt can also be incorporated into polymers using this method.

  16. Auroral particles

    NASA Astrophysics Data System (ADS)

    Evans, David S.

    1987-06-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  17. Auroral particles

    NASA Technical Reports Server (NTRS)

    Evans, David S.

    1987-01-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  18. Particle Sizer

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Microspheres are tiny plastic beads that represent the first commercial products manufactured in orbit. An example of how they are used is a new aerodynamic particle sizer designated APS 33B produced by TSI Incorporated. TSI purchased the microspheres from the National Bureau of Standards which certified their exact size and the company uses them in calibration of the APS 33B* instrument, latest in a line of TSI systems for generating counting and weighing minute particles of submicron size. Instruments are used for evaluating air pollution control devices, quantifying environments, meteorological research, testing filters, inhalation, toxicology and other areas where generation or analysis of small airborne particles is required. * The APS 33B is no longer being manufactured. An improved version, APS 3320, is now being manufactured. 2/28/97

  19. Carbon particles

    DOEpatents

    Hunt, Arlon J.

    1984-01-01

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  20. Particle Geophysics

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroyuki K. M.

    2014-05-01

    Geophysics research has long been dominated by classical mechanics, largely disregarding the potential of particle physics to augment existing techniques. The purpose of this article is to review recent progress in probing Earth's interior with muons and neutrinos. Existing results for various volcanological targets are reviewed. Geoneutrinos are also highlighted as examples in which the neutrino probes elucidate the composition of Earth's deep interior. Particle geophysics has the potential to serve as a useful paradigm to transform our understanding of Earth as dramatically as the X-ray transformed our understanding of medicine and the body.

  1. Particle blender

    DOEpatents

    Willey, Melvin G.

    1981-01-01

    An infinite blender that achieves a homogeneous mixture of fuel microspheres is provided. Blending is accomplished by directing respective groups of desired particles onto the apex of a stationary coaxial cone. The particles progress downward over the cone surface and deposit in a space at the base of the cone that is described by a flexible band provided with a wide portion traversing and in continuous contact with the circumference of the cone base and extending upwardly therefrom. The band, being attached to the cone at a narrow inner end thereof, causes the cone to rotate on its arbor when the band is subsequently pulled onto a take-up spool. As a point at the end of the wide portion of the band passes the point where it is tangent to the cone, the blended particles are released into a delivery tube leading directly into a mold, and a plate mounted on the lower portion of the cone and positioned between the end of the wide portion of the band and the cone assures release of the particles only at the tangent point.

  2. Airborne Particles.

    ERIC Educational Resources Information Center

    Ojala, Carl F.; Ojala, Eric J.

    1987-01-01

    Describes an activity in which students collect airborne particles using a common vacuum cleaner. Suggests ways for the students to convert their data into information related to air pollution and human health. Urges consideration of weather patterns when analyzing the results of the investigation. (TW)

  3. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

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

  4. Particle classifier

    SciTech Connect

    Etkin, B.

    1987-04-14

    This patent describes a classifier for particulate material comprising a housing having an inlet to receive a classifying air flow flowing in a given direction, collection means downstream of the inlet to receive material classified by the air flow, and material introduction means intermediate the inlet and the collection means to introduce particles entrained in a secondary air stream into the housing in a direction other than the given direction. The material introduction means includes a material outlet aperture in a wall of the housing extending generally perpendicular to the given direction, conveying means to convey material and the secondary air stream to the material outlet and diverting means to divert the secondary air stream to a direction generally parallel to the classifying air flow flowing in the given direction. The diverting means includes a surface extending downstream from the outlet and adjacent thereto and being dimensioned to divert the secondary airstream by a Coanda effect generally parallel to the given direction and thereby segregate the secondary air/stream from the particles and permit continued movement of the particles along predictable trajectories.

  5. Particle acceleration

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  6. Microfabricated particle focusing device

    DOEpatents

    Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

    2013-04-23

    A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

  7. Dynamics of Carroll particles

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric; Gomis, Joaquim; Longhi, Giorgio

    2014-10-01

    We investigate particles whose dynamics are invariant under the Carroll group. Although a single, free such Carroll particle has no non-trivial dynamics (the Carroll particle does not move), we show that non-trivial dynamics exists for a set of interacting Carroll particles. Furthermore, we gauge the Carroll algebra and couple the Carroll particle to these gauge fields. It turns out that for such a coupled system, even a single Carroll particle can have non-trivial dynamics.

  8. Particle Tracks in Aerogel

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In an experiment using a special air gun, particles are shot into aerogel at high velocities. Closeup of particles that have been captured in aerogel are shown here. The particles leave a carrot-shaped trail in the aerogel. Aerogel was used on the Stardust spacecraft to capture comet particles from Comet Wild 2.

  9. Particle capture device

    DOEpatents

    Jayne, John T.; Worsnop, Douglas R.

    2016-02-23

    In example embodiments, particle collection efficiency in aerosol analyzers and other particle measuring instruments is improved by a particle capture device that employs multiple collisions to decrease momentum of particles until the particles are collected (e.g., vaporized or come to rest). The particle collection device includes an aperture through which a focused particle beam enters. A collection enclosure is coupled to the aperture and has one or more internal surfaces against which particles of the focused beam collide. One or more features are employed in the collection enclosure to promote particles to collide multiple times within the enclosure, and thereby be vaporized or come to rest, rather than escape through the aperture.

  10. Laser particle sorter

    DOEpatents

    Martin, J.C.; Buican, T.N.

    1987-11-30

    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  11. Laser particle sorter

    DOEpatents

    Martin, John C.; Buican, Tudor N.

    1989-01-01

    Method and apparatus for sorting particles, such as biological particles. A first laser defines an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam interrogates the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam intersects the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis.

  12. Solar Neutral Particles

    NASA Video Gallery

    This animation shows a neutral solar particle's path leaving the sun, following the magnetic field lines out to the heliosheath. The solar particle hits a hydrogen atom, stealing its electron, and ...

  13. Charged Particle Flux Sensor

    NASA Technical Reports Server (NTRS)

    Gregory, D. A.; Stocks, C. D.

    1983-01-01

    Improved version of Faraday cup increases accuracy of measurements of flux density of charged particles incident along axis through collection aperture. Geometry of cone-and-sensing cup combination assures most particles are trapped.

  14. Particle physics: Axions exposed

    NASA Astrophysics Data System (ADS)

    Lombardo, Maria Paola

    2016-11-01

    Physicists are hunting for a particle called the axion that could solve two major puzzles in fundamental physics. An ambitious study calculates the expected mass of this particle, which might reshape the experimental searches. See Letter p.69

  15. Particle exposures and infections

    EPA Science Inventory

    Particle exposures increase the risk for human infections. Particles can deposit in the nose, pharynx, larynx, trachea, bronchi, and distal lung and, accordingly, the respiratory tract is the system most frequently infected after such exposure; however, meningitis also occurs. Ci...

  16. Classical confined particles

    NASA Technical Reports Server (NTRS)

    Horzela, Andrzej; Kapuscik, Edward

    1993-01-01

    An alternative picture of classical many body mechanics is proposed. In this picture particles possess individual kinematics but are deprived from individual dynamics. Dynamics exists only for the many particle system as a whole. The theory is complete and allows to determine the trajectories of each particle. It is proposed to use our picture as a classical prototype for a realistic theory of confined particles.

  17. Solar flare particle radiation

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.

    1972-01-01

    The characteristics of the solar particles accelerated by solar flares and subsequently observed near the orbit of the earth are studied. Considered are solar particle intensity-time profiles, the composition and spectra of solar flare events, and the propagation of solar particles in interplanetary space. The effects of solar particles at the earth, riometer observations of polar cap cosmic noise absorption events, and the production of solar cell damage at synchronous altitudes by solar protons are also discussed.

  18. Anatomy of Particle Diffusion

    ERIC Educational Resources Information Center

    Bringuier, E.

    2009-01-01

    The paper analyses particle diffusion from a thermodynamic standpoint. The main goal of the paper is to highlight the conceptual connection between particle diffusion, which belongs to non-equilibrium statistical physics, and mechanics, which deals with particle motion, at the level of third-year university courses. We start out from the fact…

  19. High energy particle astronomy.

    NASA Technical Reports Server (NTRS)

    Buffington, A.; Muller, R. A.; Smith, L. H.; Smoot, G. F.

    1972-01-01

    Discussion of techniques currently used in high energy particle astronomy for measuring charged and neutral cosmic rays and their isotope and momentum distribution. Derived from methods developed for accelerator experiments in particle physics, these techniques help perform important particle astronomy experiments pertaining to nuclear cosmic ray and gamma ray research, electron and position probes, and antimatter searches.

  20. Particle charge spectrometer

    NASA Technical Reports Server (NTRS)

    Fuerstenau, Stephen D. (Inventor)

    2004-01-01

    An airflow through a tube is used to guide a charged particle through the tube. A detector may be used to detect charge passing through the tube on the particle. The movement of the particle through the tube may be used to both detect its charge and size.

  1. When is a Particle?

    ERIC Educational Resources Information Center

    Drell, Sidney D.

    1978-01-01

    Gives a new definition for the concept of the elementary particle in nuclear physics. Explains why the existance of the quark as an elementary particle could be an accepted fact even though it lacks what traditionally identifies a particle. Compares this with the development which took place during the discovery of the neutrino in the early…

  2. Particle Accelerators in China

    NASA Astrophysics Data System (ADS)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  3. Adhesive particle shielding

    DOEpatents

    Klebanoff, Leonard Elliott; Rader, Daniel John; Walton, Christopher; Folta, James

    2009-01-06

    An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

  4. Fuzzy Logic Particle Tracking

    NASA Technical Reports Server (NTRS)

    2005-01-01

    A new all-electronic Particle Image Velocimetry technique that can efficiently map high speed gas flows has been developed in-house at the NASA Lewis Research Center. Particle Image Velocimetry is an optical technique for measuring the instantaneous two component velocity field across a planar region of a seeded flow field. A pulsed laser light sheet is used to illuminate the seed particles entrained in the flow field at two instances in time. One or more charged coupled device (CCD) cameras can be used to record the instantaneous positions of particles. Using the time between light sheet pulses and determining either the individual particle displacements or the average displacement of particles over a small subregion of the recorded image enables the calculation of the fluid velocity. Fuzzy logic minimizes the required operator intervention in identifying particles and computing velocity. Using two cameras that have the same view of the illumination plane yields two single exposure image frames. Two competing techniques that yield unambiguous velocity vector direction information have been widely used for reducing the single-exposure, multiple image frame data: (1) cross-correlation and (2) particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. For the correlation technique, the correlation peak corresponding to the average displacement of particles across the subregion must be identified. Noise on the images and particle dropout result in misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work, fuzzy logic techniques are used to determine the true

  5. CLASHING BEAM PARTICLE ACCELERATOR

    DOEpatents

    Burleigh, R.J.

    1961-04-11

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

  6. Particle Swarm Optimization

    NASA Technical Reports Server (NTRS)

    Venter, Gerhard; Sobieszczanski-Sobieski Jaroslaw

    2002-01-01

    The purpose of this paper is to show how the search algorithm known as particle swarm optimization performs. Here, particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. The paper's new contributions are improvements to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm, Results of numerical experiments for both continuous and discrete applications are presented in the paper. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in continuous applications with very good precision, albeit at a much higher computational cost than that of a typical gradient based optimizer. However, the true potential of particle swarm optimization is primarily in applications with discrete and/or discontinuous functions and variables. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors.

  7. Precision gap particle separator

    DOEpatents

    Benett, William J.; Miles, Robin; Jones, II., Leslie M.; Stockton, Cheryl

    2004-06-08

    A system for separating particles entrained in a fluid includes a base with a first channel and a second channel. A precision gap connects the first channel and the second channel. The precision gap is of a size that allows small particles to pass from the first channel into the second channel and prevents large particles from the first channel into the second channel. A cover is positioned over the base unit, the first channel, the precision gap, and the second channel. An port directs the fluid containing the entrained particles into the first channel. An output port directs the large particles out of the first channel. A port connected to the second channel directs the small particles out of the second channel.

  8. The Sisyphus particle detector

    NASA Technical Reports Server (NTRS)

    Soberman, R. K.

    1974-01-01

    The particle measurement subsystem planned for the MJS 77 mission is described. Scientific objectives with respect to Saturn's rings are as follows: (1) measure particles outside the visible rings, including particulates orbiting in more distant rings and particles scattered out of visible rings, (2) measure meteoroid environment in vicinity of Saturn, and (3) develop an understanding of the dynamics of the rings with respect to their collisional interaction with the environment.

  9. Bioactivation of particles

    DOEpatents

    Pinaud, Fabien; King, David; Weiss, Shimon

    2011-08-16

    Particles are bioactivated by attaching bioactivation peptides to the particle surface. The bioactivation peptides are peptide-based compounds that impart one or more biologically important functions to the particles. Each bioactivation peptide includes a molecular or surface recognition part that binds with the surface of the particle and one or more functional parts. The surface recognition part includes an amino-end and a carboxy-end and is composed of one or more hydrophobic spacers and one or more binding clusters. The functional part(s) is attached to the surface recognition part at the amino-end and/or said carboxy-end.

  10. Restoring particle phenomenology

    NASA Astrophysics Data System (ADS)

    Valente, Giovanni

    2015-08-01

    No-go theorems are known in the literature to the effect that, in relativistic quantum field theory, particle localizability in the strict sense violates relativistic causality. In order to account for particle phenomenology without particle ontology, Halvorson and Clifton (2002) proposed an approximate localization scheme. In a recent paper, Arageorgis and Stergiou (2013) proved a no-go result that suggests that, even within such a scheme, there would arise act-outcome correlations over the entire spacetime, thereby violating relativistic causality. Here, we show that this conclusion is untenable. In particular, we argue that one can recover particle phenomenology without having to give up relativistic causality.

  11. Detecting Space Dust Particles

    NASA Technical Reports Server (NTRS)

    Kinard, William H.; Humes, Donald H.; Kassel, Philip C., Jr.; Wortman, Jim; Singer, S. Fred; Stanley, John

    1988-01-01

    Technique records times specific craters formed in targets exposed in space and permits determination of direction in which impacting particles traveled at times of impacts. MOS capacitor is short-circuited by impact of particle striking at high speed. After recovery of targets from space, compositions of impacting particles established through post-flight laboratory analyses of residual materials in craters. On earth technique has industrial and military uses in detection of fragments driven by explosions. Studies of orbital dynamics of particles produced by solid-propellant rocket-motor firings in space made using technique.

  12. Dielectrophoretic particle-particle interaction under AC electrohydrodynamic flow conditions.

    PubMed

    Lee, Doh-Hyoung; Yu, Chengjie; Papazoglou, Elisabeth; Farouk, Bakhtier; Noh, Hongseok M

    2011-09-01

    We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data. The improved understanding of particle behaviors in AC electrohydrodynamic flows presented here will enable researchers to design better particle manipulation strategies for lab-on-a-chip applications.

  13. Pileup per particle identification

    DOE PAGES

    Bertolini, Daniele; Harris, Philip; Low, Matthew; ...

    2014-10-09

    We propose a new method for pileup mitigation by implementing “pileup per particle identification” (PUPPI). For each particle we first define a local shape α which probes the collinear versus soft diffuse structure in the neighborhood of the particle. The former is indicative of particles originating from the hard scatter and the latter of particles originating from pileup interactions. The distribution of α for charged pileup, assumed as a proxy for all pileup, is used on an event-by-event basis to calculate a weight for each particle. The weights describe the degree to which particles are pileup-like and are used tomore » rescale their four-momenta, superseding the need for jet-based corrections. Furthermore, the algorithm flexibly allows combination with other, possibly experimental, probabilistic information associated with particles such as vertexing and timing performance. We demonstrate the algorithm improves over existing methods by looking at jet pT and jet mass. As a result, we also find an improvement on non-jet quantities like missing transverse energy.« less

  14. Particle impact location detector

    NASA Technical Reports Server (NTRS)

    Auer, S. O.

    1974-01-01

    Detector includes delay lines connected to each detector surface strip. When several particles strike different strips simultaneously, pulses generated by each strip are time delayed by certain intervals. Delay time for each strip is known. By observing time delay in pulse, it is possible to locate strip that is struck by particle.

  15. Ambient Tropospheric Particles

    EPA Science Inventory

    Atmospheric particulate matter (PM) is a complex mixture of solid and liquid particles suspended in ambient air (also known as the atmospheric aerosol). Ambient PM arises from a wide-range of sources and/or processes, and consists of particles of different shapes, sizes, and com...

  16. Pileup per particle identification

    SciTech Connect

    Bertolini, Daniele; Harris, Philip; Low, Matthew; Tran, Nhan

    2014-10-09

    We propose a new method for pileup mitigation by implementing “pileup per particle identification” (PUPPI). For each particle we first define a local shape α which probes the collinear versus soft diffuse structure in the neighborhood of the particle. The former is indicative of particles originating from the hard scatter and the latter of particles originating from pileup interactions. The distribution of α for charged pileup, assumed as a proxy for all pileup, is used on an event-by-event basis to calculate a weight for each particle. The weights describe the degree to which particles are pileup-like and are used to rescale their four-momenta, superseding the need for jet-based corrections. Furthermore, the algorithm flexibly allows combination with other, possibly experimental, probabilistic information associated with particles such as vertexing and timing performance. We demonstrate the algorithm improves over existing methods by looking at jet pT and jet mass. As a result, we also find an improvement on non-jet quantities like missing transverse energy.

  17. Interactive Terascale Particle Visualization

    NASA Technical Reports Server (NTRS)

    Ellsworth, David; Green, Bryan; Moran, Patrick

    2004-01-01

    This paper describes the methods used to produce an interactive visualization of a 2 TB computational fluid dynamics (CFD) data set using particle tracing (streaklines). We use the method introduced by Bruckschen et al. [2001] that pre-computes a large number of particles, stores them on disk using a space-filling curve ordering that minimizes seeks, and then retrieves and displays the particles according to the user's command. We describe how the particle computation can be performed using a PC cluster, how the algorithm can be adapted to work with a multi-block curvilinear mesh, and how the out-of-core visualization can be scaled to 296 billion particles while still achieving interactive performance on PG hardware. Compared to the earlier work, our data set size and total number of particles are an order of magnitude larger. We also describe a new compression technique that allows the lossless compression of the particles by 41% and speeds the particle retrieval by about 30%.

  18. Teaching German Modal Particles.

    ERIC Educational Resources Information Center

    Rosler, Dietmar

    1982-01-01

    Believes modern linguistics has done little to explore German modal particles because by focusing on sentences as the basic category for linguistic thinking these words did not seem to matter. Describes model which gives students experience with these particles in meaningful communication. (Author/BK)

  19. Particle fuel diversion structure

    SciTech Connect

    Eshleman, R. D.

    1985-07-30

    A particle fuel burning furnace has an upper combustion chamber for holding a pile of particle fuel and burning the same from the bottom thereof. The furnace also includes a lower combustion chamber for after-burning combustible gases given off by the burning of solid fuel in the upper chamber and a series of spaced apart vertically-extending passageways arranged in a row and interconnecting the upper and lower chambers for communicating the combustible gases from the upper to the lower chamber. A first improved feature relates to a particle fuel delivery control device which operates an auger for filling the upper chamber with particle fuel to a desired level. A beam of light is transmitted and reflected between a photoelectric cell and reflector respectively of the device. When the particle fuel pile has grown in height during filling to the desired level the light beam is interrupted and filling is terminated. A second improved feature relates to a particle fuel diversion structure positioned in spaced relationship above and overlying the row of passageways. The structure forms a horizontal slot which extends laterally from the passageways which prevents particles of fuel from falling through the passageways and relocates the flame which burns the particle fuel pile from the bottom to a region away from the passageways.

  20. Solar Energetic Particles

    NASA Astrophysics Data System (ADS)

    Király, Péter

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

  1. RESEARCH IN PARTICLE PHYSICS

    SciTech Connect

    Kearns, Edward

    2013-07-12

    This is the final report for the Department of Energy Grant to Principal Investigators in Experimental and Theoretical Particle Physics at Boston University. The research performed was in the Energy Frontier at the LHC, the Intensity Frontier at Super-Kamiokande and T2K, the Cosmic Frontier and detector R&D in dark matter detector development, and in particle theory.

  2. Detecting Contaminant Particles Acoustically

    NASA Technical Reports Server (NTRS)

    Wyett, L. M.

    1986-01-01

    Apparatus "listens" for particles in interior of complex turbomachinery. Contact microphones are attached at several points on pump housing. Acoustic transducer also attached to housing to excite entire pump with sound. Frequency of sound is slowly raised until pump resonates. Microphones detect noise of loose particles scraping against pump parts. Such as machining chips in turbopumps or other machinery without disassembly.

  3. Anisotropic Particles in Turbulence

    NASA Astrophysics Data System (ADS)

    Voth, Greg A.; Soldati, Alfredo

    2017-01-01

    Anisotropic particles are common in many industrial and natural turbulent flows. When these particles are small and neutrally buoyant, they follow Lagrangian trajectories while exhibiting rich orientational dynamics from the coupling of their rotation to the velocity gradients of the turbulence field. This system has proven to be a fascinating application of the fundamental properties of velocity gradients in turbulence. When particles are not neutrally buoyant, they experience preferential concentration and very different preferential alignment than neutrally buoyant tracer particles. A vast proportion of the parameter range of anisotropic particles in turbulence is still unexplored, with most existing research focusing on the simple foundational cases of axisymmetric ellipsoids at low concentrations in homogeneous isotropic turbulence and in turbulent channel flow. Numerical simulations and experiments have recently developed a fairly comprehensive picture of alignment and rotation in these cases, and they provide an essential foundation for addressing more complex problems of practical importance. Macroscopic effects of nonspherical particle dynamics include preferential concentration in coherent structures and drag reduction by fiber suspensions. We review the models used to describe nonspherical particle motion, along with numerical and experimental methods for measuring particle dynamics.

  4. Imaging alpha particle detector

    DOEpatents

    Anderson, David F.

    1985-01-01

    A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  5. Imaging alpha particle detector

    DOEpatents

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  6. Elementary particles and cosmology

    NASA Astrophysics Data System (ADS)

    Dobrolyubov, M. I.; Ignatev, A. Yu.; Shaposhnikov, M. E.

    1988-12-01

    A series of lectures is devoted to actual problems which arise at the junction of elementary particle physics and cosmology. A brief review is given to the standard theory of hot universe and scenario of inflationary universe, modern state of the problem of baryon universe asymmetry and possible new mechanisms of this asymmetry formation. The possibility of construction of cosmological models on the basis of supersymmetric theories is considered: qualitative evaluation of the modern density of relic particles, cosmological restrictions for the mass of the lightest particle, astrophysical restrictions for the coupling constant of weakly interacting particles and matter are given. A perspective direction of search for light particles in light hadron decays is mentioned.

  7. Review of particle physics

    SciTech Connect

    Olive, K. A.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.

  8. Review of particle physics

    DOE PAGES

    Olive, K. A.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders,more » Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.« less

  9. HIGH ENERGY PARTICLE ACCELERATOR

    DOEpatents

    Courant, E.D.; Livingston, M.S.; Snyder, H.S.

    1959-04-14

    An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

  10. Particle Analysis Pitfalls

    NASA Technical Reports Server (NTRS)

    Hughes, David; Dazzo, Tony

    2007-01-01

    This viewgraph presentation reviews the use of particle analysis to assist in preparing for the 4th Hubble Space Telescope (HST) Servicing mission. During this mission the Space Telescope Imaging Spectrograph (STIS) will be repaired. The particle analysis consisted of Finite element mesh creation, Black-body viewfactors generated using I-DEAS TMG Thermal Analysis, Grey-body viewfactors calculated using Markov method, Particle distribution modeled using an iterative Monte Carlo process, (time-consuming); in house software called MASTRAM, Differential analysis performed in Excel, and Visualization provided by Tecplot and I-DEAS. Several tests were performed and are reviewed: Conformal Coat Particle Study, Card Extraction Study, Cover Fastener Removal Particle Generation Study, and E-Graf Vibration Particulate Study. The lessons learned during this analysis are also reviewed.

  11. DEM Particle Fracture Model

    SciTech Connect

    Zhang, Boning; Herbold, Eric B.; Homel, Michael A.; Regueiro, Richard A.

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

  12. Apparatus for measuring particle properties

    DOEpatents

    Rader, D.J.; Castaneda, J.N.; Grasser, T.W.; Brockmann, J.E.

    1998-08-11

    An apparatus is described for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle`s size can be determined from the intensity of the light scattered. The particle`s velocity can be determined from the elapsed time between various intensities of the light scattered. 11 figs.

  13. Biomimetic Particles as Therapeutics

    PubMed Central

    Green, Jordan J.

    2015-01-01

    In recent years, there have been major advances in the development of novel nanoparticle and microparticle-based therapeutics. An emerging paradigm is the incorporation of biomimetic features into these synthetic therapeutic constructs to enable them to better interface with biological systems. Through the control of size, shape, and material consistency, particle cores have been generated that better mimic natural cells and viruses. In addition, there have been significant advances in biomimetic surface functionalization of particles through the integration of bio-inspired artificial cell membranes and naturally derived cell membranes. Biomimetic technologies enable therapeutic particles to have increased potency to benefit human health. PMID:26277289

  14. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-01-01

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

  15. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-09-02

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

  16. Biomimetic particles as therapeutics.

    PubMed

    Meyer, Randall A; Sunshine, Joel C; Green, Jordan J

    2015-09-01

    In recent years, there have been major advances in the development of novel nanoparticle- and microparticle-based therapeutics. An emerging paradigm is the incorporation of biomimetic features into these synthetic therapeutic constructs to enable them to better interface with biological systems. Through the control of size, shape, and material consistency, particle cores have been generated that better mimic natural cells and viruses. In addition, there have been significant advances in biomimetic surface functionalization of particles through the integration of bio-inspired artificial cell membranes and naturally derived cell membranes. Biomimetic technologies enable therapeutic particles to have increased potency to benefit human health.

  17. Magnetic Particle Imaging

    SciTech Connect

    Minard, Kevin R.

    2010-02-01

    Rapid advances in the synthesis of superparamagnetic nanoparticles has stimulated widespread interest in their use as contrast agents for visualizing biological processes with Magnetic Resonance Imaging (MRI). With this approach, strong particle magnetism alters the MRI signal from nearby water protons and this, in turn, affects observed image contrast. Magnetic particle detection with MRI is therefore indirect and suffers from several associated problems, including poor quantification and tissuedependent performance. Magnetic Particle Imaging (MPI) overcomes these by directly measuring the amount of superparamagnetic material at each location. Mass sensitivity, spatial resolution, and imaging time is also comparable to or better than that achieved with MRI. Moreover, MPI is relatively inexpensive, meets all current safety guidelines, is quantitative, provides unambiguous contrast with tissue-independent performance, and can detect lower particle concentrations. Here, the basic principles behind MPI are described, factors affecting sensitivity and resolution are discussed, and potential utility for biomedical use is examined.

  18. Electromagnetic particle simulation codes

    NASA Technical Reports Server (NTRS)

    Pritchett, P. L.

    1985-01-01

    Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.

  19. The packing of particles

    SciTech Connect

    Cumberland, D.J.; Crawford, R.J.

    1987-01-01

    The wide range of information currently available on the packing of particles is brought together in this monograph. The authors' interest in the subject was initially aroused by the question of whether there is an optimum particle size distribution which would maximise the packing density of particles - a question which has attracted the interest of scientists and engineers for centuries. The densification of a powder mass is of relevance in a great many industries, among them the pharmaceutical, ceramic, powder metallurgy and civil engineering industries. In addition, the packing of regular - or irregular - shaped particles is also of relevance to a surprisingly large number of other industries and subject areas, i.e. the foundry industry, nuclear engineering, chemical engineering, crystallography, geology, biology, telecommunications, and so on. Accordingly, this book is written for a wide audience.

  20. Elementary particle physics

    NASA Technical Reports Server (NTRS)

    Perkins, D. H.

    1986-01-01

    Elementary particle physics is discussed. Status of the Standard Model of electroweak and strong interactions; phenomena beyond the Standard Model; new accelerator projects; and possible contributions from non-accelerator experiments are examined.

  1. Accelerating Particles with Plasma

    ScienceCinema

    Litos, Michael; Hogan, Mark

    2016-07-12

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

  2. Particle Size Analysis.

    ERIC Educational Resources Information Center

    Barth, Howard G.; Sun, Shao-Tang

    1989-01-01

    Presents a review of research focusing on scattering, elution techniques, electrozone sensing, filtration, centrifugation, comparison of techniques, data analysis, and particle size standards. The review covers the period 1986-1988. (MVL)

  3. Research in particle theory

    SciTech Connect

    Mansouri, F.; Suranyi, P; Wijewardhana, L.C.R.

    1991-10-01

    In the test particle approximation, the scattering amplitude for two-particle scattering in (2+1)-dimensional Chern-Simons-Witten gravity and supergravity was computed and compared to the corresponding metric solutions. The formalism was then extended to the exact gauge theoretic treatment of the two-particle scattering problem and compared to 't Hooft's results from the metric approach. We have studied dynamical symmetry breaking in 2+1 dimensional field theories. We have analyzed strong Extended Technicolor (ETC) models where the ETC coupling is close to a critical value. There are effective scalar fields in each of the theories. We have worked our how such scalar particles can be produced and how they decay. The {phi}{sup 4} field theory was investigated in the Schrodinger representation. The critical behavior was extracted in an arbitrary number of dimensions in second order of a systematic truncation approximation. The correlation exponent agrees with known values within a few percent.

  4. The Power of Particles

    Atmospheric Science Data Center

    2017-04-06

    ... on April 27; the color scale on the right side indicates aerosol concentrations as particles were dispersed through the atmosphere. ... from Mexico to Mississippi reveals the path of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) ...

  5. Particle Physics Masterclass

    ScienceCinema

    Helio Takai

    2016-07-12

    Students from six local high schools -- Farmingdale, Sachem East, Shoreham, Smithtown East, Ward Melville, and William Floyd -- came to Brookhaven National Laboratory to experience research with particle physicist Helio Takai. They were among more than 6,

  6. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

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

  7. Particle Physics Masterclass

    SciTech Connect

    Helio Takai

    2009-04-10

    Students from six local high schools -- Farmingdale, Sachem East, Shoreham, Smithtown East, Ward Melville, and William Floyd -- came to Brookhaven National Laboratory to experience research with particle physicist Helio Takai. They were among more than 6,

  8. Unstable particles near threshold

    NASA Astrophysics Data System (ADS)

    Chway, Dongjin; Jung, Tae Hyun; Kim, Hyung Do

    2016-07-01

    We explore the physics of unstable particles when the mother particle's mass is approximately the sum of the masses of its daughter particles. In this case, the conventional wave function renormalization factor used for the narrow width approximation is ill-defined. We propose a simple resolution of the problem that allows the use of the narrow width approximation by defining the wave function renormalization factor and the branching ratio in terms of the spectral density. We test new definitions by calculating the cross section in the Higgs portal model and a significant improvement is obtained. Meanwhile, no single decay width can be assigned to the unstable particles and non-exponential decay occurs at all time scales.

  9. Particle chemistry impactor experiment

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Snetsinger, K. G.; Ferry, G. V.; Goodman, J. K.; Verma, S.

    1990-01-01

    Polar stratospheric cloud (PSC) particles are collected on impactors and studied with regard to physical and chemical properties to help explain the importance of heterogeneous chemical reactions for stratospheric ozone depletion. The nitric, hydrochloric, and sulfuric acid content of stratospheric aerosol particles collected at 18 km altitude was determined. It is suggested that nitric acid is a component of polar stratospheric clouds. This is important for two reasons: (1) it proves that chlorine activation takes place at the surface of PSC particles by converting chemically inert chlorine nitrate to chlorine radicals that can react with ozone; and (2) if the PSC particles are large enough to settle out from the stratosphere, the possibility of nitric acid removal can result in the denitrification of the stratosphere.

  10. Alpha-particle diagnostics

    SciTech Connect

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  11. Big Bang Day: 5 Particles - 5. The Next Particle

    ScienceCinema

    None

    2016-07-12

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 5. The Next Particle The "sparticle" - a super symmetric partner to all the known particles could be the answer to uniting all the known particles and their interactions under one grand theoretical pattern of activity. But how do researchers know where to look for such phenomena and how do they know if they find them? Simon Singh reviews the next particle that physicists would like to find if the current particle theories are to ring true.

  12. Safe biodegradable fluorescent particles

    DOEpatents

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  13. PARTICLES OF DIFFERENCE.

    SciTech Connect

    SCHWARTZ,S.E.

    2000-09-21

    It is no longer appropriate, if it ever was, to think of atmospheric aerosols as homogeneous spheres of uniform composition and size. Within the United States, and even more globally, not only the mass loading but also the composition, morphology, and size distribution of atmospheric aerosols are highly variable, as a function of location, and at a given location as a function of time. Particles of a given aerodynamic size may differ from one another, and even within individual particles material may be inhomogeneously distributed, as for example, carbon spherules imbedded in much larger sulfate particles. Some of the particulate matter is primary, that is, introduced into the atmosphere directly as particles, such as carbon particles in diesel exhaust. Some is secondary, that is, formed in the atmosphere by gas-to-particle conversion. Much of the material is inorganic, mainly sulfates and nitrates resulting mainly from energy-related emissions. Some of the material is carbonaceous, in part primary, in part secondary, and of this material some is anthropogenic and some biogenic. While the heterogeneity of atmospheric aerosols complicates the problem of understanding their loading and distribution, it may well be the key to its solution. By detailed examination of the materials comprising aerosols it is possible to infer the sources of these materials. It may be possible as well to identify specific health impairing agents. The heterogeneity of aerosol particles is thus the key to identifying their sources, to understanding the processes that govern their loading and properties, and to devising control strategies that are both effective and efficient. Future research must therefore take cognizance of differences among aerosol particles and use these differences to advantage.

  14. ELEMENTARY PARTICLE INTERACTIONS

    SciTech Connect

    EFREMENKO, YURI; HANDLER, THOMAS; KAMYSHKOV, YURI; SIOPSIS, GEORGE; SPANIER, STEFAN

    2013-07-30

    The High-Energy Elementary Particle Interactions group at UT during the last three years worked on the following directions and projects: Collider-based Particle Physics; Neutrino Physics, particularly participation in “NOνA”, “Double Chooz”, and “KamLAND” neutrino experiments; and Theory, including Scattering amplitudes, Quark-gluon plasma; Holographic cosmology; Holographic superconductors; Charge density waves; Striped superconductors; and Holographic FFLO states.

  15. The Least Particle Theory

    NASA Astrophysics Data System (ADS)

    Hartsock, Robert

    2011-10-01

    The Least Particle Theory states that the universe was cast as a great sea of energy. MaX Planck declared a quantum of energy to be the least value in the universe. We declare the quantum of energy to be the least particle in the universe. Stephen Hawking declared quantum mechanics to be of no value in todays gross mechanics. That's like saying the number 1 has no place in mathematics.

  16. Statistics of indistinguishable particles.

    PubMed

    Wittig, Curt

    2009-07-02

    The wave function of a system containing identical particles takes into account the relationship between a particle's intrinsic spin and its statistical property. Specifically, the exchange of two identical particles having odd-half-integer spin results in the wave function changing sign, whereas the exchange of two identical particles having integer spin is accompanied by no such sign change. This is embodied in a term (-1)(2s), which has the value +1 for integer s (bosons), and -1 for odd-half-integer s (fermions), where s is the particle spin. All of this is well-known. In the nonrelativistic limit, a detailed consideration of the exchange of two identical particles shows that exchange is accompanied by a 2pi reorientation that yields the (-1)(2s) term. The same bookkeeping is applicable to the relativistic case described by the proper orthochronous Lorentz group, because any proper orthochronous Lorentz transformation can be expressed as the product of spatial rotations and a boost along the direction of motion.

  17. V-Particle Again?

    NASA Astrophysics Data System (ADS)

    Zhu, Shou-Hua

    This talk is mainly based on our previous work.1 We will investigate the possibility of detecting light long-lived particle (LLP) produced by high energy cosmic ray colliding with atmosphere. The LLP may penetrate the atmosphere and decay into a pair of muons near/in the neutrino telescope. Such muons can be treated as the detectable signal for neutrino telescope. The particle with such behavior is very similar with that of the first observed strange particle in cosmic ray events, which was coined historically as "V-particle" in some literature. This study is motivated by recent cosmic electron/positron observations which suggest the existence of O(TeV) dark matter and new light O(GeV) particle. It indicates that dark sector may be complicated, and there may exist more than one light particle, for example the dark gauge boson A‧ and associated dark Higgs boson h‧. In this work, we discuss the scenario with A‧ heavier than h‧ and h‧ is treated as LLP. Based on our numerical estimation, we find that the large volume neutrino telescope IceCube has the capacity to observe several tens of di-muon events per year for favorable parameters if the decay length of LLP can be comparable with the depth of atmosphere. The challenge here is how to suppress the muon background induced by cosmic rays and atmospheric neutrinos.

  18. On Characterizing Particle Shape

    NASA Technical Reports Server (NTRS)

    Ennis, Bryan J.; Rickman, Douglas; Rollins, A. Brent; Ennis, Brandon

    2014-01-01

    It is well known that particle shape affects flow characteristics of granular materials, as well as a variety of other solids processing issues such as compaction, rheology, filtration and other two-phase flow problems. The impact of shape crosses many diverse and commercially important applications, including pharmaceuticals, civil engineering, metallurgy, health, and food processing. Two applications studied here include the dry solids flow of lunar simulants (e.g. JSC-1, NU-LHT-2M, OB-1), and the flow properties of wet concrete, including final compressive strength. A multi-dimensional generalized, engineering method to quantitatively characterize particle shapes has been developed, applicable to both single particle orientation and multi-particle assemblies. The two-dimension, three dimension inversion problem is also treated, and the application of these methods to DEM model particles will be discussed. In the case of lunar simulants, flow properties of six lunar simulants have been measured, and the impact of particle shape on flowability - as characterized by the shape method developed here -- is discussed, especially in the context of three simulants of similar size range. In the context of concrete processing, concrete construction is a major contributor to greenhouse gas production, of which the major contributor is cement binding loading. Any optimization in concrete rheology and packing that can reduce cement loading and improve strength loading can also reduce currently required construction safety factors. The characterization approach here is also demonstrated for the impact of rock aggregate shape on concrete slump rheology and dry compressive strength.

  19. Particle Accelerators Test Cosmological Theory.

    ERIC Educational Resources Information Center

    Schramm, David N.; Steigman, Gary

    1988-01-01

    Discusses the symbiotic relationship of cosmology and elementary-particle physics. Presents a brief overview of particle physics. Explains how cosmological considerations set limits on the number of types of elementary particles. (RT)

  20. Tortuosity of porous particles.

    PubMed

    Barrande, M; Bouchet, R; Denoyel, R

    2007-12-01

    Tortuosity is often used as an adjustable parameter in models of transfer properties through porous media. This parameter, not reducible to classical measured microstructural parameters like specific surface area, porosity, or pore size distribution, reflects the efficiency of percolation paths, which is linked to the topology of the material. The measurement of the effective conductivity of a bed of particles saturated with an electrolyte is a simple way to evaluate tortuosity. Nevertheless, it received only little attention because of the real difficulties in both getting reliable results and interpreting data. Notably, the discrimination between the contribution of interparticle and intraparticle porosities to the tortuosity is not resolved. To our knowledge, there is no model able to fit the experimental data of the tortuosity of a suspension, and a fortiori of a particle bed, in the whole porosity range. Only empirical expressions have been proposed, but they do not allow deriving intratortuosity of a porous particle. For a dilute system, Maxwell's equation predicts the effective conductivity of suspensions of spherical particles as a function of the bulk electrolyte conductivity and of particle conductivity. The intraparticle tortuosity can be derived from the particle conductivity obtained from the Maxwell equation applied to data at infinite dilution of particles. Then, by assuming that the Maxwell equation is a first-order approximation of the conductivity as a function of porosity, we propose an explicit relation of the tortuosity tau of a suspension of porous particles, obtained by conductivity measurement, as tau = tau(epsilon, epsilon(p), tau(p)), where epsilon is the total porosity of the suspension, tau(p) is the intraparticle tortuosity, and epsilon(p) is the particle porosity. This relationship fits the experimental data in the whole porosity range and can be used to determine tau(p) from an experiment at only one porosity. Finally, the obtained

  1. Particle segregation during explosive dispersal of binary particle mixtures

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  2. Proton: the particle.

    PubMed

    Suit, Herman

    2013-11-01

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

  3. Alpha-particle microdosimetry.

    PubMed

    Chouin, Nicolas; Bardies, Manuel

    2011-07-01

    With the increasing availability of alpha emitters, targeted α-particle therapy has emerged as a solution of choice to treat haematological cancers and micrometastatic and minimal residual diseases. Alpha-particles are highly cytotoxic because of their high linear energy transfer (LET) and have a short range of a few cell diameters in tissue, assuring good treatment specificity. These radiologic features make conventional dosimetry less relevant for that context. Stochastic variations in the energy deposited in cell nuclei are important because of the microscopic target size, low number of α- particle traversals, and variation in LET along the α-particle track. Microdosimetry provides a conceptual framework that aims at a systematic analysis of the stochastic distribution of energy deposits in irradiated matter. The different quantities of microdosimetry and the different methods of microdosimetric calculations were described in the early eighties. Since then, numerous models have been published through the years and applied to analyse experimental data or to model realistic therapeutic situations. Major results have been an accurate description of the high toxicity of α-particles, and the description of the predominant effect of activity distribution at the cellular scale on toxicity or efficacy of potential targeted α-particle therapies. This last factor represents a major limitation to the use of microdosimetry in vivo because determination of the source - target distribution is complicated. The future contributions of microdosimetry in targeted α-particle therapy research will certainly depend on the ability to develop high-resolution detectors and on the implementation of pharmaco-kinetic models at the tumour microenvironment scale.

  4. Particles causing lung disease.

    PubMed Central

    Kilburn, K H

    1984-01-01

    The lung has a limited number of patterns of reaction to inhaled particles. The disease observed depends upon the location: conducting airways, terminal bronchioles and alveoli, and upon the nature of inflammation induced: acute, subacute or chronic. Many different agents cause narrowing of conducting airways (asthma) and some of these cause permanent distortion or obliteration of airways as well. Terminal bronchioles appear to be particularly susceptible to particles which cause goblet cell metaplasia, mucous plugging and ultimately peribronchiolar fibrosis. Cancer is the last outcome at the bronchial level and appears to depend upon continuous exposure to or retention of an agent in the airway and failure of the affected cells to be exfoliated which may be due to squamous metaplasia. Alveoli are populated by endothelial cells, Type I or pavement epithelial cells and metabolically active cuboidal Type II cells that produce the lungs specific surfactant, dipalmytol lecithin. Disturbances of surfactant lead to edema in distal lung while laryngeal edema due to anaphylaxis or fumes may produce asphyxia. Physical retention of indigestible particles or retention by immune memory responses may provoke hyaline membranes, stimulate alveolar lipoproteinosis and finally fibrosis. This later exuberant deposition of connective tissue has been best studied in the occupational pneumoconioses especially silicosis and asbestosis. In contrast emphysema a catabolic response, appears frequently to result from leakage or release of lysosomal proteases into the lung during processing of cigarette smoke particles. The insidious and probably most important human lung disease due to particles is bronchiolar obstruction and obliteration, producing progressive impairment of air flow. The responsible particle is the complex combination of poorly digestive lipids and complex carbohydrates with active chemicals which we call cigarette smoke. More research is needed to perfect, correct and

  5. Particle-Charge Spectrometer

    NASA Technical Reports Server (NTRS)

    Fuerstenau, Stephen; Wilson, Gregory R.

    2008-01-01

    An instrument for rapidly measuring the electric charges and sizes (from approximately 1 to approximately 100 micrometers) of airborne particles is undergoing development. Conceived for monitoring atmospheric dust particles on Mars, instruments like this one could also be used on Earth to monitor natural and artificial aerosols in diverse indoor and outdoor settings for example, volcanic regions, clean rooms, powder-processing machinery, and spray-coating facilities. The instrument incorporates a commercially available, low-noise, ultrasensitive charge-sensing preamplifier circuit. The input terminal of this circuit--the gate of a field-effect transistor--is connected to a Faraday-cage cylindrical electrode. The charged particles of interest are suspended in air or other suitable gas that is made to flow along the axis of the cylindrical electrode without touching the electrode. The flow can be channeled and generated by any of several alternative means; in the prototype of this instrument, the gas is drawn along a glass capillary tube (see upper part of figure) coaxial with the electrode. The size of a particle affects its rate of acceleration in the flow and thus affects the timing and shape of the corresponding signal peak generated by the charge-sensing amplifier. The charge affects the magnitude (and thus also the shape) of the signal peak. Thus, the signal peak (see figure) conveys information on both the size and electric charge of a sensed particle. In experiments thus far, the instrument has been found to be capable of measuring individual aerosol particle charges of magnitude greater than 350 e (where e is the fundamental unit of electric charge) with a precision of +/- 150 e. The instrument can sample particles at a rate as high as several thousand per second.

  6. Proton: The Particle

    SciTech Connect

    Suit, Herman

    2013-11-01

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

  7. Review of Particle Physics

    NASA Astrophysics Data System (ADS)

    Olive, K. A.; Particle Data Group; et al.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation. The complete Review is published online in a journal and on the website of the Particle Data Group (http://pdg.lbl.gov). The printed PDG Book contains the Summary Tables and all review articles but no longer includes the detailed tables from the Particle Listings. A Booklet with the Summary Tables and abbreviated versions of some of the review articles is also available. Contents Abstract, Contributors, Highlights and Table of ContentsAcrobat PDF (150 KB) IntroductionAcrobat PDF (456 KB) Particle Physics Summary Tables Gauge and Higgs bosonsAcrobat PDF (155 KB) LeptonsAcrobat PDF (134 KB) QuarksAcrobat PDF (84 KB) MesonsAcrobat PDF (871 KB) BaryonsAcrobat PDF (300 KB) Searches (Supersymmetry, Compositeness, etc.)Acrobat PDF (91 KB) Tests of conservation lawsAcrobat PDF (330 KB) Reviews, Tables, and Plots Detailed contents for this sectionAcrobat PDF (37 KB) Constants, Units, Atomic and Nuclear PropertiesAcrobat PDF (278 KB) Standard Model and Related TopicsAcrobat PDF (7.3 MB) Astrophysics and CosmologyAcrobat PDF (2.7 MB) Experimental Methods and CollidersAcrobat PDF (3.8 MB) Mathematical Tools or Statistics, Monte Carlo, Group

  8. A relationship between maximum packing of particles and particle size

    NASA Technical Reports Server (NTRS)

    Fedors, R. F.

    1979-01-01

    Experimental data indicate that the volume fraction of particles in a packed bed (i.e. maximum packing) depends on particle size. One explanation for this is based on the idea that particle adhesion is the primary factor. In this paper, however, it is shown that entrainment and immobilization of liquid by the particles can also account for the facts.

  9. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.

    1962-01-01

    A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

  10. Large Particle Titanate Sorbents

    SciTech Connect

    Taylor-Pashow, K.

    2015-10-08

    This research project was aimed at developing a synthesis technique for producing large particle size monosodium titanate (MST) to benefit high level waste (HLW) processing at the Savannah River Site (SRS). Two applications were targeted, first increasing the size of the powdered MST used in batch contact processing to improve the filtration performance of the material, and second preparing a form of MST suitable for deployment in a column configuration. Increasing the particle size should lead to improvements in filtration flux, and decreased frequency of filter cleaning leading to improved throughput. Deployment of MST in a column configuration would allow for movement from a batch process to a more continuous process. Modifications to the typical MST synthesis led to an increase in the average particle size. Filtration testing on dead-end filters showed improved filtration rates with the larger particle material; however, no improvement in filtration rate was realized on a crossflow filter. In order to produce materials suitable for column deployment several approaches were examined. First, attempts were made to coat zirconium oxide microspheres (196 µm) with a layer of MST. This proved largely unsuccessful. An alternate approach was then taken synthesizing a porous monolith of MST which could be used as a column. Several parameters were tested, and conditions were found that were able to produce a continuous structure versus an agglomeration of particles. This monolith material showed Sr uptake comparable to that of previously evaluated samples of engineered MST in batch contact testing.

  11. Cosmology and Particle Physics

    NASA Astrophysics Data System (ADS)

    Steigman, G.

    1982-01-01

    The cosmic connections between physics on the very largest and very smallest scales are reviewed with an emphasis on the symbiotic relation between elementary particle physics and cosmology. After a review of the early Universe as a cosmic accelerator, various cosmological and astrophysical constraints on models of particle physics are outlined. To illustrate this approach to particle physics via cosmology, reference is made to several areas of current research: baryon non-conservation and baryon asymmetry; free quarks, heavy hadrons and other exotic relics; primordial nucleosynthesis and neutrino masses. In the last few years we have witnessed the birth and growth to healthy adolescence of a new collaboration between astrophysicists and particle physicists. The most notable success of this cooperative effort has been to provide the framework for understanding, within the context of GUTs and the hot big-bang cosmology, the universal baryon asymmetry. The most exciting new predictions this effort has spawned are that exotic relics may exist in detectable abundances. In particular, we may live in a neutrino-dominated Universe. In the next few years, accummulating laboratory data (for example proton decay, neutrino masses and oscillations) coupled with theoritical work in particle physics and cosmology will ensure the growth to maturity of this joint effort.

  12. Particle physics and cosmology

    SciTech Connect

    Kolb, E.W.

    1986-10-01

    This series of lectures is about the role of particle physics in physical processes that occurred in the very early stages of the bug gang. Of particular interest is the role of particle physics in determining the evolution of the early Universe, and the effect of particle physics on the present structure of the Universe. The use of the big bang as a laboratory for placing limits on new particle physics theories will also be discussed. Section 1 reviews the standard cosmology, including primordial nucleosynthesis. Section 2 reviews the decoupling of weakly interacting particles in the early Universe, and discusses neutrino cosmology and the resulting limits that may be placed on the mass and lifetime of massive neutrinos. Section 3 discusses the evolution of the vacuum through phase transitions in the early Universe and the formation of topological defects in the transitions. Section 4 covers recent work on the generation of the baryon asymmetry by baryon-number violating reactions in Grand Unified Theories, and mentions some recent work on baryon number violation effects at the electroweak transition. Section 5 is devoted to theories of cosmic inflation. Finally, Section 6 is a discussion of the role of extra spatial dimensions in the evolution of the early Universe. 78 refs., 32 figs., 6 tabs.

  13. Lorentz force particle analyzer

    NASA Astrophysics Data System (ADS)

    Wang, Xiaodong; Thess, André; Moreau, René; Tan, Yanqing; Dai, Shangjun; Tao, Zhen; Yang, Wenzhi; Wang, Bo

    2016-07-01

    A new contactless technique is presented for the detection of micron-sized insulating particles in the flow of an electrically conducting fluid. A transverse magnetic field brakes this flow and tends to become entrained in the flow direction by a Lorentz force, whose reaction force on the magnetic-field-generating system can be measured. The presence of insulating particles suspended in the fluid produce changes in this Lorentz force, generating pulses in it; these pulses enable the particles to be counted and sized. A two-dimensional numerical model that employs a moving mesh method demonstrates the measurement principle when such a particle is present. Two prototypes and a three-dimensional numerical model are used to demonstrate the feasibility of a Lorentz force particle analyzer (LFPA). The findings of this study conclude that such an LFPA, which offers contactless and on-line quantitative measurements, can be applied to an extensive range of applications. These applications include measurements of the cleanliness of high-temperature and aggressive molten metal, such as aluminum and steel alloys, and the clean manufacturing of semiconductors.

  14. Big Bang Day: 5 Particles - 3. The Anti-particle

    ScienceCinema

    None

    2016-07-12

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

  15. Big Bang Day: 5 Particles - 3. The Anti-particle

    SciTech Connect

    2009-10-07

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

  16. Precision wood particle feedstocks

    DOEpatents

    Dooley, James H; Lanning, David N

    2013-07-30

    Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

  17. Particle fuel bed tests

    SciTech Connect

    Horn, F.L.; Powell, J.R.; Savino, J.M.

    1985-01-01

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H/sub 2/ for 12 hours with no visible reaction or weight loss.

  18. On particle track detectors

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Gruhn, T. A.; Andrus, C. H.

    1973-01-01

    Aqueous sodium hydroxide is widely used to develop charged particle tracks in polycarbonate film, particularly Lexan. The chemical nature of the etching process for this system has been determined. A method employing ultra-violet absorbance was developed for monitoring the concentration of the etch products in solution. Using this method it was possible to study the formation of the etching solution saturated in etch products. It was found that the system super-saturates to a significant extent before precipitation occurs. It was also learned that the system approaches its equilibrium state rather slowly. It is felt that both these phenomena may be due to the presence of surfactant in the solution. In light of these findings, suggestions are given regarding the preparation and maintenance of the saturated etch solution. Two additional research projects, involving automated techniques for particle track analysis and particle identification using AgCl crystals, are briefly summarized.

  19. Charged particle accelerator grating

    DOEpatents

    Palmer, R.B.

    1985-09-09

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

  20. Carbon-particle generator

    DOEpatents

    Hunt, A.J.

    1982-09-29

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  1. Moving particle composition analyzer

    NASA Technical Reports Server (NTRS)

    Auer, S. O. (Inventor)

    1976-01-01

    A mass spectrometry apparatus for analyzing the composition of moving microscopic particles is introduced. The apparatus includes a capacitor with a front electrode upon which the particles impinge, a back electrode, and a solid dielectric sandwiched between the front and back electrodes. In one embodiment, the electrodes and dielectric are arcuately shaped as concentric peripheral segments of different spheres having a common center and different radii. The front electrode and dielectric together have a thickness such that an impinging particle can penetrate them. In a second embodiment, the capacitor has planar, parallel electrodes, in which case the ejected positive ions are deflected downstream of a planar grid by a pair of spaced, arcuate capacitor plates having a region between them through which the ejected ions travel.

  2. Biological particle identification apparatus

    DOEpatents

    Salzman, Gary C.; Gregg, Charles T.; Grace, W. Kevin; Hiebert, Richard D.

    1989-01-01

    An apparatus and method for making multiparameter light scattering measurements from suspensions of biological particles is described. Fourteen of the sixteen Mueller matrix elements describing the particles under investigation can be substantially individually determined as a function of scattering angle and probing radiations wavelength, eight elements simultaneously for each of two apparatus configurations using an apparatus which incluees, in its simplest form, two polarization modulators each operating at a chosen frequency, one polarizer, a source of monochromatic electromagnetic radiation, a detector sensitive to the wavelength of radiation employed, eight phase-sensitive detectors, and appropriate electronics. A database of known biological particle suspensions can be assembled, and unknown samples can be quickly identified once measurements are performed on it according to the teachings of the subject invention, and a comparison is made with the database.

  3. Wear Particle Atlas. Revised

    DTIC Science & Technology

    1982-06-28

    Nonferrous Metals 27 1.6.2 Copper Alloys 28 1.6.3 Lead /Tin Alloys 32 1,"( Ferrous Oxides 33 1.7.1 Red Oxides of Iron 33 1.7.2 Black...exit end of the ferrogram. Ferrous (magnetic) particles are deposited in strings which follow the field lines of the magnet assembly positioned ueiow...particularly useful in research where it is desired to photograph assemblies of particles requiring a large depth of focus. However, the SEM shows only

  4. Apparatus for measuring particle properties

    DOEpatents

    Rader, Daniel J.; Castaneda, Jaime N.; Grasser, Thomas W.; Brockmann, John E.

    1998-01-01

    An apparatus for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle's size can be determined from the intensity of the light scattered. The particle's velocity can be determined from the elapsed time between various intensities of the light scattered.

  5. Analysis of preferential particle concentration

    NASA Astrophysics Data System (ADS)

    Shariff, Karim

    2008-11-01

    It is known from simulations of particle laden turbulent flows (Squires and Eaton 1991; Wang and Maxey 1993) that particles having a relaxation time nearly equal to the Kolmogorov time preferentially concentrate in regions of weak vorticity. Here we consider the set of equations for particle dilatation, strain, and rotation which provides an understanding of this behavior. This set is derived from the two-fluid equations for the coupled fluid and particle phases. Fluid strain induces particle strain, which causes particle dilatation to always decrease. Fluid rotation, on the other hand, induces particle rotation, which causes particle dilatation to always increase. Illustrative solutions are provided for spatially linear flows and the case of pure strain nicely illustrates how particles concentrate. The analysis also suggests devices and flows that would be particularly good at concentrating particles.

  6. Particle Deposition onto Enclosure Surfaces

    DTIC Science & Technology

    2009-08-20

    Rate, P 16 4.3 Comparison of vd and fi 16 5. Methods for Measurement of Particle Deposition 19 5.1 Measuring Particle Deposition Rate, p 19...deposition. 18 5. Methods for Measurement of Particle Deposition Owing to its importance for numerous engineering systems, the processes of particle...particle counter, time-of-flight aerosol spectrometer, electrical aerosol mobility analyzer, as well as aerosol generation methods , can be found in

  7. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.; Kiesling, J.D.

    1963-06-11

    A wave-guide resonator structure is designed for use in separating particles of equal momentum but differing in mass, having energies exceeding one billion eiectron volts. The particles referred to are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high energy accelerator. In the resonator a travelling electric wave is produced which travels at the same rate of speed as the unwanted particle which is thus deflected continuously over the length of the resonator. The wanted particle is slightly out of phase with the travelling wave so that over the whole length of the resonator it has a net deflection of substantially zero. The travelling wave is established in a wave guide of rectangular cross section in which stubs are provided to store magnetic wave energy leaving the electric wave energy in the main structure to obtain the desired travelling wave and deflection. The stubs are of such shape and spacing to establish a critical mathemitical relationship. (AEC)

  8. Elementary Particles and Forces.

    ERIC Educational Resources Information Center

    Quigg, Chris

    1985-01-01

    Discusses subatomic particles (quarks, leptons, and others) revealed by higher accelerator energies. A connection between forces at this subatomic level has been established, and prospects are good for a description of forces that encompass binding atomic nuclei. Colors, fundamental interactions, screening, camouflage, electroweak symmetry, and…

  9. Universality of particle multiplicities

    NASA Astrophysics Data System (ADS)

    Goulianos, K.

    1994-09-01

    We discuss the scaling properties and universality aspects of the rapidity and multiplicity distributions of particles produced in high energy hadronic and e(+)e(-) interactions. This paper is based on material presented in three lectures on pomeron phenomenology, which included a review of traditional soft pomeron physics and selected topics on hard diffraction processes probing the structure function of the pomeron.

  10. Particle-Size Analysis

    SciTech Connect

    Gee, Glendon W. ); Or, Dani; J.H. Dane and G.C. Topp

    2002-11-01

    Book Chapter describing methods of particle-size analysis for soils. Includes a variety of classification schemes. Standard methods for size distributions using pipet and hydrometer techniques are described. New laser-light scattering and related techniques are discussed. Complete with updated references.

  11. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

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

  12. Smoothed Particle Hydrodynamic Simulator

    SciTech Connect

    2016-10-05

    This code is a highly modular framework for developing smoothed particle hydrodynamic (SPH) simulations running on parallel platforms. The compartmentalization of the code allows for rapid development of new SPH applications and modifications of existing algorithms. The compartmentalization also allows changes in one part of the code used by many applications to instantly be made available to all applications.

  13. Lunar Soil Particle Separator

    NASA Technical Reports Server (NTRS)

    Berggren, Mark

    2010-01-01

    The Lunar Soil Particle Separator (LSPS) beneficiates soil prior to in situ resource utilization (ISRU). It can improve ISRU oxygen yield by boosting the concentration of ilmenite, or other iron-oxide-bearing materials found in lunar soils, which can substantially reduce hydrogen reduction reactor size, as well as drastically decreasing the power input required for soil heating

  14. Particles and Fields

    NASA Astrophysics Data System (ADS)

    Georgi, Howard; Wilczek, Frank; Tinyakov, Peter; Tytgat, Michel

    2013-03-01

    2011 marked the hundredth anniversary both of the famous Solvay conferences, and of the Geiger-Marsden experiment that launched the modern understanding of subatomic structure. I was asked to survey the status and prospects of particle physics for the anniversary Solvay conference, with appropriate perspective. This is my attempt.

  15. Particles causing lung disease

    SciTech Connect

    Kilburn, K.H.

    1984-04-01

    The lung has a limited number of patterns of reaction to inhaled particles. The disease observed depends upon the location: conducting airways, terminal bronchioles and alveoli, and upon the nature of inflammation induced: acute, subacute or chronic. Many different agents cause narrowing of conducting airways (asthma) and some of these cause permanent distortion or obliteration of airways as well. Terminal bronchioles appear to be particularly susceptible to particles which cause goblet cell metaplasia, mucous plugging and ultimately peribronchiolar fibrosis. Cancer is the last outcome at the bronchial level and appears to depend upon continuous exposure to or retention of an agent in the airway and failure of the affected cells to be exfoliated which may be due to squamous metaplasia. Alveoli are populated by endothelial cells, Type I or pavement epithelial cells and metabolically active cuboidal Type II cells that produce the lungs specific surfactant, dipalmytol lecithin. Disturbances of surfactant lead to edema in distal lung while laryngeal edema due to anaphylaxis or fumes may produce asphyxia. Physical retention of indigestible particles or retention by immune memory responses may provoke hyaline membranes, stimulate alveolar lipoproteinosis and finally fibrosis. This later exuberant deposition of connective tissue has been best studied in the occupational pneumoconioses especially silicosis and asbestosis. In contrast emphysema a catabolic response appears frequently to result from leakage or release of lysosomal proteases into the lung during processing of cigarette smoke particles. 164 references, 1 figure, 2 tables.

  16. Battery Particle Simulation

    SciTech Connect

    2014-09-15

    Two simulations show the differences between a battery being drained at a slower rate, over a full hour, versus a faster rate, only six minutes (a tenth of an hour). In both cases battery particles go from being fully charged (green) to fully drained (red), but there are significant differences in the patterns of discharge based on the rate.

  17. Nucleosome Core Particle

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Nucleosome Core Particle grown on STS-81. The fundamental structural unit of chromatin and is the basis for organization within the genome by compaction of DNA within the nucleus of the cell and by making selected regions of chromosomes available for transcription and replication. Principal Investigator's are Dr. Dan Carter and Dr. Gerard Bunick of New Century Pharmaceuticals.

  18. Elementary particle interactions

    SciTech Connect

    Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.; Ward, B.F.L.; Close, F.E.; Christophorou, L.G.

    1990-10-01

    This report discusses freon bubble chamber experiments exposed to {mu}{sup +} and neutrinos, photon-proton interactions; shower counter simulations; SLD detectors at the Stanford Linear Collider, and the detectors at the Superconducting Super Collider; elementary particle interactions; physical properties of dielectric materials used in High Energy Physics detectors; and Nuclear Physics. (LSP)

  19. Contextuality of identical particles

    NASA Astrophysics Data System (ADS)

    Kurzyński, Paweł

    2017-01-01

    There exist quantum phenomena that cannot be explained by noncontextual hidden-variable theories, yet the majority of them requires measurements that are performed on a single quantum system at a time. This fact constrains the phenomenon of contextuality to the microscopic domain. It is therefore natural to ask if quantum contextuality can be observed in measurements on collections of particles. Since particles in nature are identical, one can expect that such contextuality would be linked to bosonic and fermionic properties. Analysis of quantum contextuality in such scenarios would broaden our understanding of nonclassical effects in composite systems and perhaps would give us a hint on how to observe quantum phenomena in the macroscopic world. In this work I propose a generalization of quantum contextuality to the case of many identical particles. I show that a type of contextuality exhibited by a collection of particles (state dependent, state independent, or noncontextual) depends on their type and their number. I also discuss further properties of this generalization and identify major open questions.

  20. Particle Astrophysics Using Balloons

    NASA Astrophysics Data System (ADS)

    Seo, E. S.

    Cosmic rays, energetic particles coming from outer space, bring us information about the physical processes that accelerate particles to relativistic energies, about the effects of those particles in driving dynamical processes in our Galaxy, and about the distribution of matter and fields in interstellar space. Cosmic rays were discovered in the early twentieth century using a balloon-borne electroscope. Balloons are currently being used for answering fundamental questions about the cosmos: (1) Is the Universe symmetric, and if so where is the antimatter? (2) What is the dark matter? (3) How do cosmic rays get their enormous energies? (4) Can the entire energy spectrum of cosmic rays result from a single acceleration mechanism? (5) Are supernovae really the sources of cosmic rays? (6) What is the history of cosmic rays in the Galaxy? (7) What is the origin of the "knee" in the cosmic ray energy spectrum? etc. The status of results from past balloon-borne measurements and expected results from ongoing and planned future balloon-borne particle astrophysics experiments will be reviewed.

  1. Insights into particle cycling from thorium and particle data.

    PubMed

    Lam, Phoebe J; Marchal, Olivier

    2015-01-01

    Marine particles are a main vector by which the biological carbon pump in the ocean transfers carbon from the atmosphere to the deep ocean. Marine particles exist in a continuous spectrum of sizes, but they can be functionally grouped into a small, suspended class (which constitutes most of the total particle mass) and a large, sinking class (which contributes most of the particle flux). These two classes are connected by aggregation and disaggregation processes. The interplay of processes that create, aggregate, and destroy marine particles determines the strength and transfer efficiency of the biological pump. Measurements of radiocarbon, barium, and organic biomarkers on suspended and sinking particles have provided qualitative insights into particle dynamics, and measurements of thorium isotopes have provided quantitative estimates of rates. Here, we review what has been learned so far about particle dynamics in the ocean from chemical measurements on suspended and sinking particles. We then discuss future directions for this approach.

  2. Particle Swarm Optimization Toolbox

    NASA Technical Reports Server (NTRS)

    Grant, Michael J.

    2010-01-01

    The Particle Swarm Optimization Toolbox is a library of evolutionary optimization tools developed in the MATLAB environment. The algorithms contained in the library include a genetic algorithm (GA), a single-objective particle swarm optimizer (SOPSO), and a multi-objective particle swarm optimizer (MOPSO). Development focused on both the SOPSO and MOPSO. A GA was included mainly for comparison purposes, and the particle swarm optimizers appeared to perform better for a wide variety of optimization problems. All algorithms are capable of performing unconstrained and constrained optimization. The particle swarm optimizers are capable of performing single and multi-objective optimization. The SOPSO and MOPSO algorithms are based on swarming theory and bird-flocking patterns to search the trade space for the optimal solution or optimal trade in competing objectives. The MOPSO generates Pareto fronts for objectives that are in competition. A GA, based on Darwin evolutionary theory, is also included in the library. The GA consists of individuals that form a population in the design space. The population mates to form offspring at new locations in the design space. These offspring contain traits from both of the parents. The algorithm is based on this combination of traits from parents to hopefully provide an improved solution than either of the original parents. As the algorithm progresses, individuals that hold these optimal traits will emerge as the optimal solutions. Due to the generic design of all optimization algorithms, each algorithm interfaces with a user-supplied objective function. This function serves as a "black-box" to the optimizers in which the only purpose of this function is to evaluate solutions provided by the optimizers. Hence, the user-supplied function can be numerical simulations, analytical functions, etc., since the specific detail of this function is of no concern to the optimizer. These algorithms were originally developed to support entry

  3. Movement of particles using sequentially activated dielectrophoretic particle trapping

    DOEpatents

    Miles, Robin R.

    2004-02-03

    Manipulation of DNA and cells/spores using dielectrophoretic (DEP) forces to perform sample preparation protocols for polymerized chain reaction (PCR) based assays for various applications. This is accomplished by movement of particles using sequentially activated dielectrophoretic particle trapping. DEP forces induce a dipole in particles, and these particles can be trapped in non-uniform fields. The particles can be trapped in the high field strength region of one set of electrodes. By switching off this field and switching on an adjacent electrodes, particles can be moved down a channel with little or no flow.

  4. Particle analyzing method and apparatus

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Griffin, C. E.; Norris, D. D.; Friedlander, S. K. (Inventor)

    1980-01-01

    The rapid chemical analysis of particles in aerosols can be accomplished using an apparatus which produces a controlled stream of individual particles from an environment, and another apparatus which vaporizes and ionizes the particles moving in free flight, for analysis by a mass spectrometer. The device for producing the stream of particles includes a capillary tube through which the air with suspended particles moves, a skimmer with a small opening spaced from an end of the capillary tube to receive particles passing through the tube, and a vacuum pump which removes air from between the tube and skimmer and creates an inflow of air and particles through the tube. The particles passing through the skimmer opening can be simultaneously vaporized and ionized while in free flight, by a laser beam of sufficient intensity that is directed across the path of the free flying particles.

  5. Experimental Particle Physics

    SciTech Connect

    Rosenfeld, Carl; Mishra, Sanjib R.; Petti, Roberto; Purohit, Milind V.

    2014-08-31

    The high energy physics group at the University of South Carolina, under the leadership of Profs. S.R. Mishra, R. Petti, M.V. Purohit, J.R. Wilson (co-PI's), and C. Rosenfeld (PI), engaged in studies in "Experimental Particle Physics." The group collaborated with similar groups at other universities and at national laboratories to conduct experimental studies of elementary particle properties. We utilized the particle accelerators at the Fermi National Accelerator Laboratory (Fermilab) in Illinois, the Stanford Linear Accelerator Center (SLAC) in California, and the European Center for Nuclear Research (CERN) in Switzerland. Mishra, Rosenfeld, and Petti worked predominantly on neutrino experiments. Experiments conducted in the last fifteen years that used cosmic rays and the core of the sun as a source of neutrinos showed conclusively that, contrary to the former conventional wisdom, the "flavor" of a neutrino is not immutable. A neutrino of flavor "e," "mu," or "tau," as determined from its provenance, may swap its identity with one of the other flavors -- in our jargon, they "oscillate." The oscillation phenomenon is extraordinarily difficult to study because neutrino interactions with our instruments are exceedingly rare -- they travel through the earth mostly unimpeded -- and because they must travel great distances before a substantial proportion have made the identity swap. Three of the experiments that we worked on, MINOS, NOvA, and LBNE utilize a beam of neutrinos from an accelerator at Fermilab to determine the parameters governing the oscillation. Two other experiments that we worked on, NOMAD and MIPP, provide measurements supportive of the oscillation experiments. Good measurements of the neutrino oscillation parameters may constitute a "low energy window" on related phenomena that are otherwise unobservable because they would occur only at energies way above the reach of conceivable accelerators. Purohit and Wilson participated in the BaBar experiment

  6. Effective particle magnetic moment of multi-core particles

    NASA Astrophysics Data System (ADS)

    Ahrentorp, Fredrik; Astalan, Andrea; Blomgren, Jakob; Jonasson, Christian; Wetterskog, Erik; Svedlindh, Peter; Lak, Aidin; Ludwig, Frank; van IJzendoorn, Leo J.; Westphal, Fritz; Grüttner, Cordula; Gehrke, Nicole; Gustafsson, Stefan; Olsson, Eva; Johansson, Christer

    2015-04-01

    In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron microscopy (TEM). We also investigate how the effective particle magnetic moment is coupled to the individual moments of the single-domain nanocrystals by using different measurement techniques: DC magnetometry, AC susceptometry, dynamic light scattering and TEM. We have studied two magnetic multi-core particle systems - BNF Starch from Micromod with a median particle diameter of 100 nm and FeraSpin R from nanoPET with a median particle diameter of 70 nm - and one single-core particle system - SHP25 from Ocean NanoTech with a median particle core diameter of 25 nm.

  7. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, V.

    1992-12-15

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

  8. Cosmology and particle physics

    NASA Technical Reports Server (NTRS)

    Turner, Michael S.

    1988-01-01

    The interplay between cosmology and elementary particle physics is discussed. The standard cosmology is reviewed, concentrating on primordial nucleosynthesis and discussing how the standard cosmology has been used to place constraints on the properties of various particles. Baryogenesis is discussed, showing how a scenario in which the B-, C-, and CP-violating interactions in GUTs provide a dynamical explanation for the predominance of matter over antimatter and for the present baryon-to-photon ratio. It is shown how the very early dynamical evolution of a very weakly coupled scalar field which is initially displaced from the minimum of its potential may explain a handful of very fundamental cosmological facts which are not explained by the standard cosmology.

  9. Research in particle physics

    SciTech Connect

    Not Available

    1993-08-01

    This proposal presents the research accomplishments and ongoing activities of Boston University researchers in high energy physics. Some changes have been made in the structure of the program from the previous arrangement of tasks. Task B, Accelerator Design Physics, is being submitted as a separate proposal for an independent grant; this will be consistent with the nature of the research and the source of funding. We are active in seven principal areas which will be discussed in this report: Colliding Beams - physics of e{sup +}e{sup {minus}} and {bar p}p collisions; MACRO Experiment - search for magnetic monopoles and study of cosmic rays; Proton Decay - search for nucleon instability and study of neutrino interactions; Particle Theory - theoretical high energy particle physics, including two Outstanding Junior Investigator awards; Muon G-2 - measurement of the anomalous magnetic moment of the muon; SSCintcal - calorimetry for the GEM Experiment; and Muon detectors for the GEM Experiment.

  10. Aviation Particle Emissions Workshop

    NASA Technical Reports Server (NTRS)

    Wey, Chowen C. (Editor)

    2004-01-01

    The Aviation Particle Emissions Workshop was held on November 18 19, 2003, in Cleveland, Ohio. It was sponsored by the National Aeronautic and Space Administration (NASA) under the Vehicle Systems Program (VSP) and the Ultra- Efficient Engine Technology (UEET) Project. The objectives were to build a sound foundation for a comprehensive particulate research roadmap and to provide a forum for discussion among U.S. stakeholders and researchers. Presentations included perspectives from the Federal Aviation Administration, the U.S. Environmental Protection Agency, NASA, and United States airports. There were five interactive technical sessions: sampling methodology, measurement methodology, particle modeling, database, inventory and test venue, and air quality. Each group presented technical issues which generated excellent discussion. The five session leads collaborated with their members to present summaries and conclusions to each content area.

  11. Narrowband magnetic particle imaging.

    PubMed

    Goodwill, Patrick W; Scott, Greig C; Stang, Pascal P; Conolly, Steven M

    2009-08-01

    The magnetic particle imaging (MPI) method directly images the magnetization of super-paramagnetic iron oxide (SPIO) nanoparticles, which are contrast agents commonly used in magnetic resonance imaging (MRI). MPI, as originally envisioned, requires a high-bandwidth receiver coil and preamplifier, which are difficult to optimally noise match. This paper introduces Narrowband MPI, which dramatically reduces bandwidth requirements and increases the signal-to-noise ratio for a fixed specific absorption rate. We employ a two-tone excitation (called intermodulation) that can be tailored for a high-Q, narrowband receiver coil. We then demonstrate a new MPI instrument capable of full 3-D tomographic imaging of SPIO particles by imaging acrylic and tissue phantoms.

  12. Particle processing technology

    NASA Astrophysics Data System (ADS)

    Yoshio, Sakka

    2014-02-01

    In recent years, there has been strong demand for the development of novel devices and equipment that support advanced industries including IT/semiconductors, the environment, energy and aerospace along with the achievement of higher efficiency and reduced environmental impact. Many studies have been conducted on the fabrication of innovative inorganic materials with novel individual properties and/or multifunctional properties including electrical, dielectric, thermal, optical, chemical and mechanical properties through the development of particle processing. The fundamental technologies that are key to realizing such materials are (i) the synthesis of nanoparticles with uniform composition and controlled crystallite size, (ii) the arrangement/assembly and controlled dispersion of nanoparticles with controlled particle size, (iii) the precise structural control at all levels from micrometer to nanometer order and (iv) the nanostructural design based on theoretical/experimental studies of the correlation between the local structure and the functions of interest. In particular, it is now understood that the application of an external stimulus, such as magnetic energy, electrical energy and/or stress, to a reaction field is effective in realizing advanced particle processing [1-3]. This special issue comprises 12 papers including three review papers. Among them, seven papers are concerned with phosphor particles, such as silicon, metals, Si3N4-related nitrides, rare-earth oxides, garnet oxides, rare-earth sulfur oxides and rare-earth hydroxides. In these papers, the effects of particle size, morphology, dispersion, surface states, dopant concentration and other factors on the optical properties of phosphor particles and their applications are discussed. These nanoparticles are classified as zero-dimensional materials. Carbon nanotubes (CNT) and graphene are well-known one-dimensional (1D) and two-dimensional (2D) materials, respectively. This special issue also

  13. Dynamic radioactive particle source

    DOEpatents

    Moore, Murray E; Gauss, Adam Benjamin; Justus, Alan Lawrence

    2012-06-26

    A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

  14. Universality of particle multiplicities

    SciTech Connect

    Goulianos, K. |

    1994-09-01

    We discuss the scaling properties and universality aspects of the rapidity and multiplicity distributions of particles produced in high energy hadronic and e{sup +}e{sup {minus}} interactions. This paper is based on material presented in three lectures on pomeron phenomenology, which included a review of traditional soft pomeron physics and selected topics on hard diffraction processes probing the structure function of the pomeron.

  15. BRL Particle Sizing Interferometer

    DTIC Science & Technology

    1982-07-01

    possible operational conditions. The parameters associated with a fuel spray which may be expected to have a significant impact on PSI performance are...could be obtained for two possible viewing geometries. As Appendix II points out, A can be increased by using slit apertures to reduce Ax. In...particle number density and aerosol mass concentration using the model described in Appendix II. Inputs required are relative slit width Kappa, and

  16. Incremental Particle Swarm Optimization

    NASA Astrophysics Data System (ADS)

    Xu, Xiaohua; Pan, Zhoujin; Xi, Yanqiu; Chen, Ling

    By simulating the population size of the human evolution, a PSO algorithm with increment of particle size (IPPSO) was proposed. Without changing the PSO operations, IPPSO can obtain better solutions with less time cost by modifying the structure of traditional PSO. Experimental results show that IPPSO using logistic model is more efficient and requires less computation time than using linear function in solving more complex program problems.

  17. The STEIN Particle Detector

    DTIC Science & Technology

    2015-02-27

    associated with solar disturbances, magnetic storms and magnetospheric substorms. AF-STEIN has several distinct advantages over standard detectors flown on...low-earth- orbit (LEO) satellites. AF-STEIN provides the sensitivity, temporal resolution, energy resolution (~1 keV FWHM), dynamic range, and energy...essentially all important suprathermal (~4 to 200 keV) particle populations associated with solar disturbances, magnetic storms and magnetospheric substorms

  18. Radiation in Particle Simulations

    SciTech Connect

    More, R; Graziani, F; Glosli, J; Surh, M

    2010-11-19

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third method is a hybrid molecular dynamics/Monte Carlo (MD/MC) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions. The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc. This approach is inspired by the virial expansion method of equilibrium statistical mechanics. Using a combination of these methods we believe it is possible to do atomic-scale particle simulations of

  19. Interplanetary charged particle environments

    NASA Technical Reports Server (NTRS)

    Divine, T. N.

    1973-01-01

    Current state-of-the-art knowledge of the solar wind, solar particle events, and galactic cosmic rays is reviewed for the development of space vehicle design criteria based on these interplanetary environments. These criteria are described quantitatively in terms of intensity, flux and fluence, and their dependences on time, position and energy, and the associated probabilities and related parameters, for electrons, protons and other ions.

  20. Particle-mesh techniques

    NASA Technical Reports Server (NTRS)

    Macneice, Peter

    1995-01-01

    This is an introduction to numerical Particle-Mesh techniques, which are commonly used to model plasmas, gravitational N-body systems, and both compressible and incompressible fluids. The theory behind this approach is presented, and its practical implementation, both for serial and parallel machines, is discussed. This document is based on a four-hour lecture course presented by the author at the NASA Summer School for High Performance Computational Physics, held at Goddard Space Flight Center.

  1. PARTICLE BEAM TRACKING CIRCUIT

    DOEpatents

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  2. Relaxation from particle production

    NASA Astrophysics Data System (ADS)

    Hook, Anson; Marques-Tavares, Gustavo

    2016-12-01

    We consider using particle production as a friction force by which to implement a "Relaxion" solution to the electroweak hierarchy problem. Using this approach, we are able to avoid superplanckian field excursions and avoid any conflict with the strong CP problem. The relaxation mechanism can work before, during or after inflation allowing for inflationary dynamics to play an important role or to be completely decoupled.

  3. Particle sensor array

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor); Lieneweg, Udo (Inventor)

    1994-01-01

    A particle sensor array which in a preferred embodiment comprises a static random access memory having a plurality of ion-sensitive memory cells, each such cell comprising at least one pull-down field effect transistor having a sensitive drain surface area (such as by bloating) and at least one pull-up field effect transistor having a source connected to an offset voltage. The sensitive drain surface area and the offset voltage are selected for memory cell upset by incident ions such as alpha-particles. The static random access memory of the present invention provides a means for selectively biasing the memory cells into the same state in which each of the sensitive drain surface areas is reverse biased and then selectively reducing the reversed bias on these sensitive drain surface areas for increasing the upset sensitivity of the cells to ions. The resulting selectively sensitive memory cells can be used in a number of applications. By way of example, the present invention can be used for measuring the linear energy transfer of ion particles, as well as a device for assessing the resistance of CMOS latches to Cosmic Ray induced single event upsets. The sensor of the present invention can also be used to determine the uniformity of an ion beam.

  4. Particle theory and cosmology

    SciTech Connect

    Not Available

    1990-01-01

    The overall objective of the research supported by this contract is to further our understanding of the basic building blocks of matter as well as the role fundamental interactions play in cosmology and astrophysics. Astrophysical data, such as from high energy cosmic rays and large scale structure of the universe, are employed to constrain particle physics theories. Particle collisions at Tevatron and higher (SSC) energies are also under investigation. During the past year a systematic reanalysis of the correlation between solar activity and the solar neutrino flux was undertaken. The conclusion seems to be that the Homestake experimental data show a correlation at a significant level, supporting the hypothesis that the neutrino possesses a magnetic moment. A separate, but related, theoretical investigation of electromagnetic properties of elementary particles has led to the discovery of a class of models in which the neutrino is endowed with an appreciable magnetic moment while its remains small. Altogether members of the group have been co-authors of 28 papers during the grant year on topics ranging from fermion masses to the role of ultra-high energy hadronic interactions in cosmic ray physics.

  5. Particle Velocity Measuring System

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor)

    1998-01-01

    Method and apparatus are provided for determining the velocity of individual food particles within a liquid/solid food mixture that is cooked by an aseptic cooking method whereby the food mixture is heated as it flows through a flowline. At least one upstream and at least one downstream microwave transducer are provided to determine the minimum possible travel time of the fastest food particle through the flowline. In one embodiment, the upstream detector is not required. In another embodiment, a plurality of small dipole antenna markers are secured to a plurality of food particles to provide a plurality of signals as the markers pass the upstream and downstream transducers. The dipole antenna markers may also include a non-linear element to reradiate a harmonic frequency of a transmitter frequency. Upstream and downstream transducers include dipole antennas that are matched to the impedance of the food slurry and a signal transmission cable by various impedance matching means including unbalanced feed to the antennas.

  6. Alpha Particle Diagnostic

    SciTech Connect

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  7. Particle Theory & Cosmology

    SciTech Connect

    Shafi, Qaisar; Barr, Steven; Gaisser, Thomas; Stanev, Todor

    2015-03-31

    1. Executive Summary (April 1, 2012 - March 31, 2015) Title: Particle Theory, Particle Astrophysics and Cosmology Qaisar Shafi University of Delaware (Principal Investigator) Stephen M. Barr, University of Delaware (Co-Principal Investigator) Thomas K. Gaisser, University of Delaware (Co-Principal Investigator) Todor Stanev, University of Delaware (Co-Principal Investigator) The proposed research was carried out at the Bartol Research included Professors Qaisar Shafi Stephen Barr, Thomas K. Gaisser, and Todor Stanev, two postdoctoral fellows (Ilia Gogoladze and Liucheng Wang), and several graduate students. Five students of Qaisar Shafi completed their PhD during the period August 2011 - August 2014. Measures of the group’s high caliber performance during the 2012-2015 funding cycle included pub- lications in excellent refereed journals, contributions to working groups as well as white papers, and conference activities, which together provide an exceptional record of both individual performance as well as overall strength. Another important indicator of success is the outstanding quality of the past and current cohort of graduate students. The PhD students under our supervision regularly win the top departmental and university awards, and their publications records show excellence both in terms of quality and quantity. The topics covered under this grant cover the frontline research areas in today’s High Energy Theory & Phenomenology. For Professors Shafi and Barr they include LHC related topics including supersymmetry, collider physics, fl vor physics, dark matter physics, Higgs boson and seesaw physics, grand unifi and neutrino physics. The LHC two years ago discovered the Standard Model Higgs boson, thereby at least partially unlocking the secrets behind electroweak symmetry breaking. We remain optimistic that new and exciting physics will be found at LHC 14, which explain our focus on physics beyond the Standard Model. Professors Shafi continued his

  8. Summary of Alpha Particle Transport

    SciTech Connect

    Medley, S.S.; White, R.B.; Zweben, S.J.

    1998-08-19

    This paper summarizes the talks on alpha particle transport which were presented at the 5th International Atomic Energy Agency's Technical Committee Meeting on "Alpha Particles in Fusion Research" held at the Joint European Torus, England in September 1997.

  9. Fundamental principles of particle detectors

    SciTech Connect

    Fernow, R.C.

    1988-01-01

    This paper goes through the fundamental physics of particles-matter interactions which is necessary for the detection of these particles with detectors. A listing of 41 concepts and detector principles are given. 14 refs., 11 figs.

  10. Filling carbon nanotubes with particles.

    PubMed

    Kim, Byong M; Qian, Shizhi; Bau, Haim H

    2005-05-01

    The filling of carbon nanotubes (CNTs) with fluorescent particles was studied experimentally and theoretically. The fluorescent signals emitted by the particles were visible through the walls of the nanotubes, and the particles inside the tubes were observable with an electron microscope. Taking advantage of the template-grown carbon nanotubes' transparency to fluorescent light, we measured the filling rate of the tubes with particles at room conditions. Liquids such as ethylene glycol, water, and ethylene glycol/water mixtures, laden with 50 nm diameter fluorescent particles, were brought into contact with 500 nm diameter CNTs. The liquid and the particles' transport were observed, respectively, with optical and fluorescence microscopy. The CNTs were filled controllably with particles by the complementary action of capillary forces and the evaporation of the liquid. The experimental results were compared and favorably agreed with theoretical predictions. This is the first report on fluorescence studies of particle transport in carbon nanotubes.

  11. Particle-free microchip processing

    DOEpatents

    Geller, A.S.; Rader, D.J.

    1996-06-04

    Method and apparatus for reducing particulate contamination in microchip processing are disclosed. The method and apparatus comprise means to reduce particle velocity toward the wafer before the particles can be deposited on the wafer surface. A reactor using electric fields to reduce particle velocity and prevent particulate contamination is disclosed. A reactor using a porous showerhead to reduce particle velocities and prevent particulate contamination is disclosed. 5 figs.

  12. Particle-free microchip processing

    DOEpatents

    Geller, Anthony S.; Rader, Daniel J.

    1996-01-01

    Method and apparatus for reducing particulate contamination in microchip processing are disclosed. The method and apparatus comprise means to reduce particle velocity toward the wafer before the particles can be deposited on the wafer surface. A reactor using electric fields to reduce particle velocity and prevent particulate contamination is disclosed. A reactor using a porous showerhead to reduce particle velocities and prevent particulate contamination is disclosed.

  13. Dynamic simulation of particle sedimentation

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongzhen; Prosperetti, Andrea

    2004-11-01

    The sedimentation of 1024 spheres has been simulated via a recently developed method:Physalis Method. Particles are initially randomly distributed and periodic boundary conditions are assumed. The time evolution of the particle spatial distribution is studied by meassuering the structure factor. Properties of particles velocity distribution, e.g. variance, time autocorrelation, have been studied. The effects of particle rotation and collision are discussed.

  14. Amps particle accelerator definition study

    NASA Technical Reports Server (NTRS)

    Sellen, J. M., Jr.

    1975-01-01

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

  15. Particle Analysis in Forensic Science.

    PubMed

    Bisbing, R E; Schneck, W M

    2006-07-01

    Microscopic trace evidence includes particles from many sources such as biologicals, soil, building materials, metals, explosives, gunshot residues, and cosmetics. The particles are identified by morphological analysis, microscopy, and chemical analysis. Their identity is confirmed by comparison with reference materials or other comparison samples. The probative value of particles of forensic interest depends on their nature and the circumstances of their presence.

  16. Hydrodynamic particle focusing design using fluid-particle interaction.

    PubMed

    Zhou, Teng; Liu, Zhenyu; Wu, Yihui; Deng, Yongbo; Liu, Yongshun; Liu, Geng

    2013-01-01

    For passive sheathless particles focusing in microfluidics, the equilibrium positions of particles are typically controlled by micro channels with a V-shaped obstacle array (VOA). The design of the obstacles is mainly based on the distribution of flow streamlines without considering the existence of particles. We report an experimentally verified particle trajectory simulation using the arbitrary Lagrangian-Eulerian (ALE) fluid-particle interaction method. The particle trajectory which is strongly influenced by the interaction between the particle and channel wall is systematically analyzed. The numerical experiments show that the streamline is a good approximation of particle trajectory only when the particle locates on the center of the channel in depth. As the advantage of fluid-particle interaction method is achieved at a high computational cost and the streamline analysis is complex, a heuristic dimensionless design objective based on the Faxen's law is proposed to optimize the VOA devices. The optimized performance of particle focusing is verified via the experiments and ALE method.

  17. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D

    2016-05-17

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  18. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D.

    2011-12-27

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  19. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    SciTech Connect

    Kaduchak, Gregory; Ward, Michael D

    2014-10-21

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  20. Solar Energetic Particle Variations

    NASA Technical Reports Server (NTRS)

    Reames, D. V.

    2003-01-01

    In the largest solar energetic-particle (SEP) events, acceleration occurs at shock waves driven out from the Sun by coronal mass ejections (CMEs). In fact, the highest proton intensities directly measured near Earth at energies up to approximately 1 GeV occur at the time of passage of shocks, which arrive about a day after the CMEs leave the Sun. CME-driven shocks expanding across magnetic fields can fill over half of the heliosphere with SEPs. Proton-generated Alfven waves trap particles near the shock for efficient acceleration but also throttle the intensities at Earth to the streaming limit early in the events. At high energies, particles begin to leak from the shock and the spectrum rolls downward to form an energy-spectral 'knee' that can vary in energy from approximately 1 MeV to approximately 1 GeV in different events. All of these factors affect the radiation dose as a function of depth and latitude in the Earth's atmosphere and the risk to astronauts and equipment in space. SEP ionization of the polar atmosphere produces nitrates that precipitate to become trapped in the polar ice. Observations of nitrate deposits in ice cores reveal individual large SEP events and extend back approximately 400 years. Unlike sunspots, SEP events follow the approximately 80-100-year Gleissberg cycle rather faithfully and are now at a minimum in that cycle. The largest SEP event in the last 400 years appears to be related to the flare observed by Carrington in 1859, but the probability of SEP events with such large fluences falls off sharply because of the streaming limit.

  1. Hadron particle theory

    SciTech Connect

    Alonso, J.R.

    1995-05-01

    Radiation therapy with ``hadrons`` (protons, neutrons, pions, ions) has accrued a 55-year track record, with by now over 30,000 patients having received treatments with one of these particles. Very good, and in some cases spectacular results are leading to growth in the field in specific well-defined directions. The most noted contributor to success has been the ability to better define and control the radiation field produced with these particles, to increase the dose delivered to the treatment volume while achieving a high degree of sparing of normal tissue. An additional benefit is the highly-ionizing, character of certain beams, leading to creater cell-killing potential for tumor lines that have historically been very resistant to radiation treatments. Until recently these treatments have been delivered in laboratories and research centers whose primary, or original mission was physics research. With maturity in the field has come both the desire to provide beam facilities more accessible to the clinical setting, of a hospital, as well as achieving, highly-efficient, reliable and economical accelerator and beam-delivery systems that can make maximum advantage of the physical characteristics of these particle beams. Considerable work in technology development is now leading, to the implementation of many of these ideas, and a new generation of clinically-oriented facilities is beginning to appear. We will discuss both the physical, clinical and technological considerations that are driving these designs, as well as highlighting, specific examples of new facilities that are either now treating, patients or that will be doing so in the near future.

  2. Radiation in Particle Simulations

    SciTech Connect

    More, R M; Graziani, F R; Glosli, J; Surh, M

    2009-06-15

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known (section 3). The second method expands the electromagnetic field in normal modes (plane-waves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion (section 4). The third method is a hybrid MD/MC (molecular dynamics/Monte Carlo) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions (section 5). The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc.(section 6). This approach is inspired by the Virial expansion method of equilibrium statistical mechanics.

  3. Particle Beam Radiography

    NASA Astrophysics Data System (ADS)

    Peach, Ken; Ekdahl, Carl

    2014-02-01

    Particle beam radiography, which uses a variety of particle probes (neutrons, protons, electrons, gammas and potentially other particles) to study the structure of materials and objects noninvasively, is reviewed, largely from an accelerator perspective, although the use of cosmic rays (mainly muons but potentially also high-energy neutrinos) is briefly reviewed. Tomography is a form of radiography which uses multiple views to reconstruct a three-dimensional density map of an object. There is a very wide range of applications of radiography and tomography, from medicine to engineering and security, and advances in instrumentation, specifically the development of electronic detectors, allow rapid analysis of the resultant radiographs. Flash radiography is a diagnostic technique for large high-explosive-driven hydrodynamic experiments that is used at many laboratories. The bremsstrahlung radiation pulse from an intense relativistic electron beam incident onto a high-Z target is the source of these radiographs. The challenge is to provide radiation sources intense enough to penetrate hundreds of g/cm2 of material, in pulses short enough to stop the motion of high-speed hydrodynamic shocks, and with source spots small enough to resolve fine details. The challenge has been met with a wide variety of accelerator technologies, including pulsed-power-driven diodes, air-core pulsed betatrons and high-current linear induction accelerators. Accelerator technology has also evolved to accommodate the experimenters' continuing quest for multiple images in time and space. Linear induction accelerators have had a major role in these advances, especially in providing multiple-time radiographs of the largest hydrodynamic experiments.

  4. On particle oscillations

    NASA Astrophysics Data System (ADS)

    Góźdź, Marek; Góźdź, Andrzej

    2014-05-01

    It has been firmly established that neutrinos change their flavour during propagation. This feature is attributed to the feature that each flavour eigenstate is a superposition of three mass eigenstates, which propagate with different frequencies. This picture, although widely accepted, is wrong in the simplest approach and requires quite sophisticated treatment based on the wave-packet description within quantum field theory. In this communication we present a novel, much simpler explanation and show that oscillations among massive particles can be obtained in a natural way. We use the framework of quantum mechanics with time being a physical observable, not just a parameter.

  5. Physics of windblown particles

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Leach, Rodman; Marshall, John R.; White, Bruce; Iversen, James D.; Nickling, William G.; Gillette, Dale; Sorensen, Michael

    1987-01-01

    A laboratory facility proposed for the Space Station to investigate fundamental aspects of windblown particles is described. The experiments would take advantage of the environment afforded in earth orbit and would be an extension of research currently being conducted on the geology and physics of windblown sediments on earth, Mars, and Venus. Aeolian (wind) processes are reviewed in the planetary context, the scientific rational is given for specific experiments to be conducted, the experiment apparatus (the Carousel Wind Tunnel, or CWT) is described, and a plan presented for implementing the proposed research program.

  6. Particle acceleration in flares

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  7. Particle-Hole Ladders

    NASA Astrophysics Data System (ADS)

    Feldman, Joel; Knörrer, Horst; Trubowitz, Eugene

    A self contained analysis demonstrates that the sum of all particle-hole ladder contributions for a two dimensional, weakly coupled fermion gas with a strictly convex Fermi curve at temperature zero is bounded. This is used in our construction of two dimensional Fermi liquids. This article contains the statements of the main results. The proofs are contained in the full, electronic, article. Electronic Supplementary Material: Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00220-004-1038-2.

  8. Plasma and particles

    NASA Astrophysics Data System (ADS)

    Špatenka, Petr; Vacková, Tat'ana; Nováček, Vojtěch; Jeníková, Zdenka

    2016-12-01

    Plasma has been proved as a standard industrial method for surface treatment of solid bulk materials. Recently plasma has also been used in connection with production, treatment and functionalization of powder and granulate materials. Functionalization was originally developed for hydrophylization of hydrophobic surfaces of particles made from various materials. An industrial scale device with a capacity of several hundreds of tons per year based on plasma treatment will be presented. As examples of the applications are given plasma treated polyethylene powder dispersed in the water; and very good adhesion of polymer powders to metals or glass, which is promising for development of new generation of thermoplastic composites.

  9. The Auroral Particles experiment

    NASA Technical Reports Server (NTRS)

    1981-01-01

    An instrument for the detection of particles in the energy range of 0.1 ev to 80 Kev was designed, built, tested, calibrated, and flown onboard the spacecraft ATS-6. Data from this instrument generated the following research: intensive studies of the plasma in the vicinity of the spacecraft; global variations of plasmas; correlative studies using either other spacecraft or ground based measurements; and studies of spacecraft interactions with ambient plasmas including charging, local electric fields due to differential charging, and active control of spacecraft potential. Results from this research are presented.

  10. Particle bed reactor modeling

    NASA Technical Reports Server (NTRS)

    Sapyta, Joe; Reid, Hank; Walton, Lew

    1993-01-01

    The topics are presented in viewgraph form and include the following: particle bed reactor (PBR) core cross section; PBR bleed cycle; fuel and moderator flow paths; PBR modeling requirements; characteristics of PBR and nuclear thermal propulsion (NTP) modeling; challenges for PBR and NTP modeling; thermal hydraulic computer codes; capabilities for PBR/reactor application; thermal/hydralic codes; limitations; physical correlations; comparison of predicted friction factor and experimental data; frit pressure drop testing; cold frit mask factor; decay heat flow rate; startup transient simulation; and philosophy of systems modeling.

  11. Small Particle Pollutants

    NASA Technical Reports Server (NTRS)

    1976-01-01

    NASA and the EPA are cooperating to measure particle size of all elements in aerosols from airports, coal-fired power stations, municipal waste incinerators, and other combustion aerosol sources. Langley intends to sample the air using its proton-induced x-ray emission technique initially developed to determine aerosols in jet-engine exhaust. Proton technique is important because no other rapid, nondestructive method now exists for measuring trace element compositions of massive amounts of air. Method can also analyze human tissue and hair samples to determine exposure to toxic elements.

  12. Microgravity Particle Dynamics

    NASA Technical Reports Server (NTRS)

    Clark, Ivan O.; Johnson, Edward J.

    1996-01-01

    This research seeks to identify the experiment design parameters for future flight experiments to better resolve the effects of thermal and velocity gradients on gas-solid flows. By exploiting the reduced body forces and minimized thermal convection current of reduced gravity experiments, features of gas-solid flow normally masked by gravitationally induced effects can be studied using flow regimes unattainable under unigravity. This paper assesses the physical scales of velocity, length, time, thermal gradient magnitude, and velocity gradient magnitude likely to be involved in laminar gas-solid multiphase flight experiments for 1-100 micro-m particles.

  13. Dusty-Plasma Particle Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2005-01-01

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

  14. Particle data reduction in Japan

    NASA Technical Reports Server (NTRS)

    Nakayama, Mitsushige

    1987-01-01

    The characterization of atomized particles generated by various atomizer and the mechanics of their evaporation and combustion processes were studied. The need existed for visualizing the internal structure of flames including evaporation and combustion processes as well as for a better way of understanding spray particle generation mechanisms and internal structures. A particle sizer based on Fraunhofer diffraction for detecting particle size and in-line Fraunhofer holograms for observation of local spray particles were used. A novel visualizing technique based on Computer Technology was developed and is discussed.

  15. Apparatus for blending small particles

    DOEpatents

    Bradley, R.A.; Reese, C.R.; Sease, J.D.

    1975-08-26

    An apparatus is described for blending small particles and uniformly loading the blended particles in a receptacle. Measured volumes of various particles are simultaneously fed into a funnel to accomplish radial blending and then directed onto the apex of a conical splitter which collects the blended particles in a multiplicity of equal subvolumes. Thereafter the apparatus sequentially discharges the subvolumes for loading in a receptacle. A system for blending nuclear fuel particles and loading them into fuel rod molds is described in a preferred embodiment. (auth)

  16. Interaction of Burning Metal Particles

    NASA Technical Reports Server (NTRS)

    Dreizin, Edward L.; Berman, Charles H.; Hoffmann, Vern K.

    1999-01-01

    Physical characteristics of the combustion of metal particle groups have been addressed in this research. The combustion behavior and interaction effects of multiple metal particles has been studied using a microgravity environment, which presents a unique opportunity to create an "aerosol" consisting of relatively large particles, i.e., 50-300 m diameter. Combustion behavior of such an aerosol could be examined using methods adopted from well-developed single particle combustion research. The experiment included fluidizing relatively large (order of 100 m diameter) uniform metal particles under microgravity and igniting such an "aerosol" using a hot wire igniter. The flame propagation and details of individual particle combustion and particle interaction have been studied using a high speed movie and video-imaging with cameras coupled with microscope lenses to resolve individual particles. Interference filters were used to separate characteristic metal and metal oxide radiation bands from the thermal black body radiation. Recorded flame images were digitized and various image processing techniques including flame position tracking, color separation, and pixel by pixel image comparison were employed to understand the processes occurring in the burning aerosol. The development of individual particle flames, merging or separation, and extinguishment as well as induced particle motion have been analyzed to identify the mechanisms governing these processes. Size distribution, morphology, and elemental compositions of combustion products were characterized and used to link the observed in this project aerosol combustion phenomena with the recently expanded mechanism of single metal particle combustion.

  17. Interaction of Burning Metal Particles

    NASA Technical Reports Server (NTRS)

    Dreizin, Edward L.; Berman, Charles H.; Hoffmann, Vern K.

    1999-01-01

    Physical characteristics of the combustion of metal particle groups have been addressed in this research. The combustion behavior and interaction effects of multiple metal particles has been studied using a microgravity environment, which presents a unique opportunity to create an "aerosol" consisting of relatively large particles, i.e., 50-300 micrometer diameter. Combustion behavior of such an aerosol could be examined using methods adopted from well-developed single particle combustion research. The experiment included fluidizing relatively large (order of 100 micrometer diameter) uniform metal particles under microgravity and igniting such an "aerosol" using a hot wire igniter. The flame propagation and details of individual particle combustion and particle interaction have been studied using a high speed movie and video-imaging with cameras coupled with microscope lenses to resolve individual particles. Interference filters were used to separate characteristic metal and metal oxide radiation bands form the thermal black body radiation. Recorded flame images were digitized and employed to understand the processes occurring in the burning aerosol. The development of individual particle flames, merging or separation, and extinguishing as well as induced particle motion have been analyzed to identify the mechanisms governing these processes. Size distribution, morphology, and elemental compositions of combustion products were characterized and used to link the observed in this project aerosol combustion phenomena with the recently expanded mechanism of single metal particle combustion.

  18. Classification of Volatile Engine Particles

    SciTech Connect

    Cheng, Mengdawn

    2013-01-01

    Volatile particles cannot be detected at the engine exhaust by an aerosol detector. They are formed when the exhaust is mixed with ambient air downstream. Lack of a precise definition of volatile engine particles has been an impediment to engine manufacturers and regulatory agencies involved in the development of an effective control strategy. It is beyond doubt that volatile particles from combustion sources contribute to the atmospheric particulate burden, and the effect of that contribution is a critical issue in the ongoing research in the areas of air quality and climate change. A new instrument, called volatile particle separator (VPS), has been developed. It utilizes a proprietary microporous metallic membrane to separate particles from vapors. VPS data were used in the development of a two-parameter function to quantitatively classify, for the first time, the volatilization behavior of engine particles. The value of parameter A describes the volatilization potential of an aerosol. A nonvolatile particle has a larger A-value than a volatile one. The value of parameter k, an effective evaporation energy barrier, is found to be much smaller for small engine particles than that for large engine particles. The VPS instrument provides a means beyond just being a volatile particle remover; it enables a numerical definition to characterize volatile engine particles.

  19. Particle physics---Experimental

    SciTech Connect

    Lord, J.J.; Boynton, P.E.; Burnett, T.H.; Wilkes, R.J.

    1991-08-21

    We are continuing a research program in particle astrophysics and high energy experimental particle physics. We have joined the DUMAND Collaboration, which is constructing a deep undersea astrophysical neutrino detector near Hawaii. Studies of high energy hadronic interactions using emulsion chamber techniques were also continued, using balloon flight exposures to ultra-high cosmic ray nuclei (JACEE) and accelerator beams. As members of the DUMAND Collaboration, we have responsibility for development a construction of critical components for the deep undersea neutrino detector facility. We have designed and developed the acoustical positioning system required to permit reconstruction of muon tracks with sufficient precision to meet the astrophysical goals of the experiment. In addition, we are making significant contributions to the design of the database and triggering system to be used. Work has been continuing in other aspects of the study of multiparticle production processes in nuclei. We are participants in a joint US/Japan program to study nuclear interactions at energies two orders of magnitude greater than those of existing accelerators, using balloon-borne emulsion chambers. On one of the flights we found two nuclear interactions of multiplicity over 1000 -- one with a multiplicity of over 2000 and pseudorapidity density {approximately} 800 in the central region. At the statistical level of the JACEE experiment, the frequency of occurrence of such events is orders of magnitude too large. We have continued our ongoing program to study hadronic interactions in emulsions exposed to high energy accelerator beams.

  20. Particle physics -- Future directions

    SciTech Connect

    Chris Quigg

    2001-11-29

    Wonderful opportunities await particle physics over the next decade, with the coming of the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino and a top quark a top quark. Here I have in mind the work of the B factories and the Tevatron collider on CP violation and the weak interactions of the b quark; the wonderfully sensitive experiments at Brookhaven, CERN, Fermilab, and Frascati on CP violation and rare decays of kaons; the prospect of definitive accelerator experiments on neutrino oscillations and the nature of the neutrinos; and a host of new experiments on the sensitivity frontier. We might even learn to read experiment for clues about the dimensionality of spacetime. If we are inventive enough, we may be able to follow this rich menu with the physics opportunities offered by a linear collider and a (muon storage ring) neutrino factory. I expect a remarkable flowering of experimental particle physics, and of theoretical physics that engages with experiment. I describe some of the great questions before us and the challenges of providing the instruments that will be needed to define them more fully and eventually to answer them.

  1. Some Annihilating Particle Systems.

    NASA Astrophysics Data System (ADS)

    Balding, David

    Available from UMI in association with The British Library. Requires signed TDF. Systems of annihilating and coalescing particles on both infinite and periodic one-dimensional state spaces are studied. These systems have various applications in the physical sciences, in particular they are useful as simple models of diffusion-limited reactions. A unified approach to computing properties of the systems using duality methods is presented and it is shown that many results in the scientific literature, derived using diverse techniques, are readily obtained in this general framework. The transition distributions of the processes with arbitrary initial configurations are characterized in terms of two-particle annihilation processes. Further, a concise expression for the distribution of the cardinality of the processes with finite initial configurations is given and particular cases of interest from the applications perspective are described in detail. Asymptotic site occupancies, previously known for certain classes of initial configurations, are derived for all spatially stationary configurations. The asymptotic spatial structure is described for many cases by showing convergence to point processes whose properties are given.

  2. Holographic particle detection

    NASA Technical Reports Server (NTRS)

    Bowen, Theodore

    1988-01-01

    The feasibility was studied of developing a novel particle track detector based on the detection of 1p-1s emission radiation from electron bubbles in liquid helium. The principles, design, construction, and initial testing of the detection system have been described in previous reports. The main obstacle encountered was the construction of the liquid-helium tight infrared windows. Despite numerous efforts in testing and redesigning the windows, the problem of window leakage at low temperature persisted. Due to limited time and resources, attention was switched to investigating the possibility of using room-temperature liquid as the detection medium. A possible mechanism was the detection of de-excitation radiation emitted from localized electrons in common liquids where electrons exhibit low mobilities, as suggested in the previous report. The purity of the liquid is critical in this method as the dissolved impurities (such as oxygen), even in trace amounts, will act as scavengers of electrons. Another mechanism is discussed whereby the formation of the superoxide ions by electron scavenging behavior of dissolved oxygen is exploited to detect the track of ionizing particles. An experiment to measure the ionization current produced in a liquid by a pulsed X-ray beam in order to study propertiies of the ions is also reported.

  3. Particle therapy for noncancer diseases

    SciTech Connect

    Bert, Christoph; Engenhart-Cabillic, Rita; Durante, Marco

    2012-04-15

    Radiation therapy using high-energy charged particles is generally acknowledged as a powerful new technique in cancer treatment. However, particle therapy in oncology is still controversial, specifically because it is unclear whether the putative clinical advantages justify the high additional costs. However, particle therapy can find important applications in the management of noncancer diseases, especially in radiosurgery. Extension to other diseases and targets (both cranial and extracranial) may widen the applications of the technique and decrease the cost/benefit ratio of the accelerator facilities. Future challenges in this field include the use of different particles and energies, motion management in particle body radiotherapy and extension to new targets currently treated by catheter ablation (atrial fibrillation and renal denervation) or stereotactic radiation therapy (trigeminal neuralgia, epilepsy, and macular degeneration). Particle body radiosurgery could be a future key application of accelerator-based particle therapy facilities in 10 years from today.

  4. Analysis of particle kinematics in spheronization via particle image velocimetry.

    PubMed

    Koester, Martin; Thommes, Markus

    2013-02-01

    Spheronization is a wide spread technique in pellet production for many pharmaceutical applications. Pellets produced by spheronization are characterized by a particularly spherical shape and narrow size distribution. The particle kinematic during spheronization is currently not well-understood. Therefore, particle image velocimetry (PIV) was implemented in the spheronization process to visualize the particle movement and to identify flow patterns, in order to explain the influence of various process parameters. The spheronization process of a common formulation was recorded with a high-speed camera, and the images were processed using particle image velocimetry software. A crosscorrelation approach was chosen to determine the particle velocity at the surface of the pellet bulk. Formulation and process parameters were varied systematically, and their influence on the particle velocity was investigated. The particle stream shows a torus-like shape with a twisted rope-like motion. It is remarkable that the overall particle velocity is approximately 10-fold lower than the tip speed of the friction plate. The velocity of the particle stream can be correlated to the water content of the pellets and the load of the spheronizer, while the rotation speed was not relevant. In conclusion, PIV was successfully applied to the spheronization process, and new insights into the particle velocity were obtained.

  5. Echo particle image velocimetry.

    PubMed

    DeMarchi, Nicholas; White, Christopher

    2012-12-27

    The transport of mass, momentum, and energy in fluid flows is ultimately determined by spatiotemporal distributions of the fluid velocity field.(1) Consequently, a prerequisite for understanding, predicting, and controlling fluid flows is the capability to measure the velocity field with adequate spatial and temporal resolution.(2) For velocity measurements in optically opaque fluids or through optically opaque geometries, echo particle image velocimetry (EPIV) is an attractive diagnostic technique to generate "instantaneous" two-dimensional fields of velocity.(3,4,5,6) In this paper, the operating protocol for an EPIV system built by integrating a commercial medical ultrasound machine(7) with a PC running commercial particle image velocimetry (PIV) software(8) is described, and validation measurements in Hagen-Poiseuille (i.e., laminar pipe) flow are reported. For the EPIV measurements, a phased array probe connected to the medical ultrasound machine is used to generate a two-dimensional ultrasound image by pulsing the piezoelectric probe elements at different times. Each probe element transmits an ultrasound pulse into the fluid, and tracer particles in the fluid (either naturally occurring or seeded) reflect ultrasound echoes back to the probe where they are recorded. The amplitude of the reflected ultrasound waves and their time delay relative to transmission are used to create what is known as B-mode (brightness mode) two-dimensional ultrasound images. Specifically, the time delay is used to determine the position of the scatterer in the fluid and the amplitude is used to assign intensity to the scatterer. The time required to obtain a single B-mode image, t, is determined by the time it take to pulse all the elements of the phased array probe. For acquiring multiple B-mode images, the frame rate of the system in frames per second (fps) = 1/δt. (See 9 for a review of ultrasound imaging.) For a typical EPIV experiment, the frame rate is between 20-60 fps

  6. Volatile particles measured by vapor-particle separator

    SciTech Connect

    Cheng, Meng -Dawn; Corporan, Edwin

    2016-08-25

    Vapor-Particle Separator (VPS) is a new technology developed for characterization of the volatile fraction of particulate matter in a combustion aerosol population. VPS incorporates a novel metallic membrane and operates in a cross-flow filtration mode for separation of vapor and solid (i.e. non-volatile) particles. Demonstration of the VPS technology on aircraft engine-emitted particles has led to the improvement of the technology and increased confidence on the robustness of its field performance. In this study, the performance of the VPS was evaluated against the Particle Measurement Programme (PMP) volatile particle remover (VPR), a standardized device used in heavy duty diesel engines for separation and characterization of non-volatile particulate matter. Using tetracontane particles in the laboratory reveals that the VPS performed reasonably well in removing the volatile species. In the field conditions, a single-mode particle size distribution was found for emitted particles from a T63 turboshaft engine at both idle and cruise engine power conditions. Removal of the volatile T63 engine particles by the VPS was consistent with that of PMP VPR. In tests on an F117 turbofan engine, the size distribution at the idle (4% rated) engine power condition was found to be bimodal, with the first mode consisting of particles smaller than 10nm, which are believed to be mostly semi-volatile particles, while the second mode of larger size was a mixture of semi-volatile and non-volatile particles. The distribution was single modal at the 33% rated engine power with no secondary mode observed. Altogether, for particles emitted by both engines, the removal efficiency of the VPS appears to surpass that of the PMP VPR by 8-10%.

  7. Volatile particles measured by vapor-particle separator

    DOE PAGES

    Cheng, Meng -Dawn; Corporan, Edwin

    2016-08-25

    Vapor-Particle Separator (VPS) is a new technology developed for characterization of the volatile fraction of particulate matter in a combustion aerosol population. VPS incorporates a novel metallic membrane and operates in a cross-flow filtration mode for separation of vapor and solid (i.e. non-volatile) particles. Demonstration of the VPS technology on aircraft engine-emitted particles has led to the improvement of the technology and increased confidence on the robustness of its field performance. In this study, the performance of the VPS was evaluated against the Particle Measurement Programme (PMP) volatile particle remover (VPR), a standardized device used in heavy duty diesel enginesmore » for separation and characterization of non-volatile particulate matter. Using tetracontane particles in the laboratory reveals that the VPS performed reasonably well in removing the volatile species. In the field conditions, a single-mode particle size distribution was found for emitted particles from a T63 turboshaft engine at both idle and cruise engine power conditions. Removal of the volatile T63 engine particles by the VPS was consistent with that of PMP VPR. In tests on an F117 turbofan engine, the size distribution at the idle (4% rated) engine power condition was found to be bimodal, with the first mode consisting of particles smaller than 10nm, which are believed to be mostly semi-volatile particles, while the second mode of larger size was a mixture of semi-volatile and non-volatile particles. The distribution was single modal at the 33% rated engine power with no secondary mode observed. Altogether, for particles emitted by both engines, the removal efficiency of the VPS appears to surpass that of the PMP VPR by 8-10%.« less

  8. Unlike-particle collision operator for gyrokinetic particle simulations

    SciTech Connect

    Kolesnikov, R.A.; Wang, W.X.; Hinton, F.L.

    2010-08-01

    Plasmas in modern tokamak experiments contain a significant fraction of impurity ion species in addition to main deuterium background. A new unlike-particle collision operator for {delta}f particle simulation has been developed to self-consistently study the non-local effects of impurities on neoclassical transport in toroidal plasmas. A new algorithm for simulation of cross-collisions between different ion species includes test-particle and conserving field-particle operators. The field-particle operator is designed to enforce conservation of number, momentum and energy. It was shown that the new operator correctly simulates the thermal equilibration of different plasma components. It was verified that the ambipolar radial electric field reaches steady state when the total radial guiding center particle current vanishes.

  9. Anomalous dispersions of `hedgehog' particles

    NASA Astrophysics Data System (ADS)

    Bahng, Joong Hwan; Yeom, Bongjun; Wang, Yichun; Tung, Siu On; Hoff, J. Damon; Kotov, Nicholas

    2015-01-01

    Hydrophobic particles in water and hydrophilic particles in oil aggregate, but can form colloidal dispersions if their surfaces are chemically camouflaged with surfactants, organic tethers, adsorbed polymers or other particles that impart affinity for the solvent and increase interparticle repulsion. A different strategy for modulating the interaction between a solid and a liquid uses surface corrugation, which gives rise to unique wetting behaviour. Here we show that this topographical effect can also be used to disperse particles in a wide range of solvents without recourse to chemicals to camouflage the particles' surfaces: we produce micrometre-sized particles that are coated with stiff, nanoscale spikes and exhibit long-term colloidal stability in both hydrophilic and hydrophobic media. We find that these `hedgehog' particles do not interpenetrate each other with their spikes, which markedly decreases the contact area between the particles and, therefore, the attractive forces between them. The trapping of air in aqueous dispersions, solvent autoionization at highly developed interfaces, and long-range electrostatic repulsion in organic media also contribute to the colloidal stability of our particles. The unusual dispersion behaviour of our hedgehog particles, overturning the notion that like dissolves like, might help to mitigate adverse environmental effects of the use of surfactants and volatile organic solvents, and deepens our understanding of interparticle interactions and nanoscale colloidal chemistry.

  10. Particle separations by electrophoretic techniques

    SciTech Connect

    Ballou, N.E.; Petersen, S.L.; Ducatte, G.R.; Remcho, V.T.

    1996-03-01

    A new method for particle separations based on capillary electrophoresis has been developed and characterized. It uniquely separates particles according to their chemical nature. Separations have been demonstrated with chemically modified latex particles and with inorganic oxide and silicate particles. Separations have been shown both experimentally and theoretically to be essentially independent of particle size in the range of about 0.2 {mu}m to 10 {mu}m. The method has been applied to separations of U0{sub 2} particles from environmental particulate material. For this, an integrated method was developed for capillary electrophoretic separation, collection of separated fractions, and determinations of U0{sub 2} and environmental particles in each fraction. Experimental runs with the integrated method on mixtures of UO{sub 2} particles and environmental particulate material demonstrated enrichment factors of 20 for UO{sub 2} particles in respect to environmental particles in the U0{sub 2}containing fractions. This enrichment factor reduces the costs and time for processing particulate samples by the lexan process by a factor of about 20.

  11. Particle fuel delivery control device

    SciTech Connect

    Eshleman, R. D.

    1985-04-30

    A particle fuel burning furnace has an upper combustion chamber for holding a pile of particle fuel and burning the same from the bottom thereof. The furnace also includes a lower combustion chamber for afterburning combustible gases given off by the burning of solid fuel in the upper chamber and a series of spaced apart verrtically-extending passageways arranged in a row and interconnecting the upper and lower chambers for communicating the combustible gases from the upper to the lower chamber. A first improved feature relates to a particle fuel delivery control device which operates an auger for filling the upper chamber with particle fuel to a particle fuel to a desired level. A beam of light is transmitted and reflected between a photoelectric cell and reflector respectively of the device. When the particle fuel pile has grown in height during filling to the desired level the light beam is interrupted and filling is terminated. A second improved feature relates to a particle fuel diversion structure positioned in space relationship above and overlying the row of passageways. The structure forms a horizontal slot which extends laterally from the passageways which prevents particles of fuel from falling rhoguh the passageways and particles of fuel from falling through the passageways and relocates the flame which burns the particle fuel pile from the bottom to a region away from the passageways.

  12. Formation of Bidisperse Particle Clouds

    NASA Astrophysics Data System (ADS)

    Er, Jenn Wei; Zhao, Bing; Law, Adrian W. K.; Adams, E. Eric

    2014-11-01

    When a group of dense particles is released instantaneously into water, their motion has been conceptualized as a circulating particle thermal (Ruggerber 2000). However, Wen and Nacamuli (1996) observed the formation of particle clumps characterized by a narrow, fast moving core shedding particles into wakes. They observed the clump formation even for particles in the non-cohesive range as long as the source Rayleigh number was large (Ra > 1E3) or equivalently the source cloud number (Nc) was small (Nc < 3.2E2). This physical phenomenon has been investigated by Zhao et al. (2014) through physical experiments. They proposed the theoretical support for Nc dependence and categorized the formation processes into cloud formation, transitional regime and clump formation. Previous works focused mainly on the behavior of monodisperse particles. The present study further extends the experimental investigation to the formation process of bidisperse particles. Experiments are conducted in a glass tank with a water depth of 90 cm. Finite amounts of sediments with various weight proportions between coarser and finer particles are released from a cylindrical tube. The Nc being tested ranges from 6E-3 to 9.9E-2, which covers all the three formation regimes. The experimental results showed that the introduction of coarse particles promotes cloud formation and reduce the losses of finer particles into the wake. More quantitative descriptions of the effects of source conditions on the formation processes will be presented during the conference.

  13. The Particle Cleanliness Validation System

    SciTech Connect

    Stowers, I.F.; Ravizza, D.L.

    2001-12-21

    The Particle Cleanliness Validation System (PCVS) is a combination of a surface particle collection tool and a microscope based data, reduction system for determining the particle cleanliness of mechanical and optical surfaces at LLNL. Livermore is currently constructing the National Ignition Facility (NIF), a large 192 beam laser system for studying fusion physics. The laser is entirely enclosed. in aluminum and stainless steel vessels containing several environments; air, argon, and vacuum. It contains uncoated optics as well as hard dielectric coated and softer solgel coated optics which are, to varying degrees, sensitive to opaque particles, translucent particles, and molecular contamination. To quantify the particulate matter on structural surfaces during vendor cleaning and installation, a novel instrument has been developed to-both collect surface particles and to quantify the number and size distribution of these particles. The particles are collected on membrane filter paper which is ''swiped'' on a test surface for a proscribed distance to collect sufficient particles to significantly exceed the cleanliness of the filter paper. The swipe paper is then placed into a cassette for protection from further. contamination and transported to a microscope with x-y motorized stage and image analysis software, The surface of the swipe paper is scanned to determine both the background particle level of the paper, the cassette cover, and the portion of the paper which made contact with the test surface. The cumulative size distribution of the collected particles are displayed in size bins from 5 to 200 {micro}m. The quantity of particles exceeding 5 {micro}m is used to compute the IEST-STD-1246D cleanliness Level. Eight image analysis microscopes have been constructed for use with several dozen particle collection tools. About 30,000 cleanliness measurements have been taken to assure the clean construction and operation of the NIF laser system.

  14. Backscattering of agglomerate particles

    NASA Astrophysics Data System (ADS)

    Zubko, Evgenij; Ovcharenko, Andrey; Bondarenko, Sergey; Shkuratov, Yuriy; Scotto, Cathy S.; Merritt, Charles; Hart, Matthew B.; Eversole, Jay D.; Videen, Gorden W.

    2004-12-01

    We examine how aggregation affects the light-scattering signatures, especially the polarization in the near-backward-scattering direction. We use the discrete dipole approximation (DDA) to study the backscatter of agglomerate particles consisting of oblong monomers. We examine the effects of monomer number and packing structure on the resulting negative polarization branch at small phase angle. We find large a dependence on the orientation of the monomers within the agglomerate and a smaller dependence on the number of monomers, suggesting that the mechanism producing the negative polarization minimum depends strongly on the interactions between the individual monomers. We also examine experimental measurements of substrates composed of biological cells. We find that the light-scattering signatures in the backward direction are not only different for different spore species, but for spores that have been prepared using different methodologies. These signatures are reproducible in different substrates composed of the spores from the same batches.

  15. Ultrafine particles in cities.

    PubMed

    Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

    2014-05-01

    Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts.

  16. Cooled particle accelerator target

    DOEpatents

    Degtiarenko, Pavel V.

    2005-06-14

    A novel particle beam target comprising: a rotating target disc mounted on a retainer and thermally coupled to a first array of spaced-apart parallel plate fins that extend radially inwardly from the retainer and mesh without physical contact with a second array of spaced-apart parallel plate fins that extend radially outwardly from and are thermally coupled to a cooling mechanism capable of removing heat from said second array of spaced-apart fins and located within the first array of spaced-apart parallel fins. Radiant thermal exchange between the two arrays of parallel plate fins provides removal of heat from the rotating disc. A method of cooling the rotating target is also described.

  17. Particle thermophoresis in liquids.

    PubMed

    Parola, A; Piazza, R

    2004-11-01

    We present a microscopic description of thermophoretic phenomena in dilute suspensions of spherical colloids. The specific particle/solvent interfacial interactions generate a force density field F on the surrounding fluid which in turn gives rise to an "effective force" on the colloid. In our approach, such a force turns out to be solely related to the non-conservative anisotropic contribution to F brought forth by the thermal gradient. By adopting a Smoluchowski picture of colloid motion, we find a general expression for the Soret coefficient S(T), which we apply to the specific cases of neutral colloids in pure solvent and of Debye-Hückel systems. For the latter, our result for S(T) agrees with those obtained by previous hydrodynamic approaches.

  18. Particle beam injection system

    DOEpatents

    Jassby, Daniel L.; Kulsrud, Russell M.

    1977-01-01

    This invention provides a poloidal divertor for stacking counterstreaming ion beams to provide high intensity colliding beams. To this end, method and apparatus are provided that inject high energy, high velocity, ordered, atomic deuterium and tritium beams into a lower energy, toroidal, thermal equilibrium, neutral, target plasma column that is magnetically confined along an endless magnetic axis in a strong restoring force magnetic field having helical field lines to produce counterstreaming deuteron and triton beams that are received bent, stacked and transported along the endless axis, while a poloidal divertor removes thermal ions and electrons all along the axis to increase the density of the counterstreaming ion beams and the reaction products resulting therefrom. By balancing the stacking and removal, colliding, strong focused particle beams, reaction products and reactions are produced that convert one form of energy into another form of energy.

  19. Theoretical Particle Astrophysics

    SciTech Connect

    Kamionkowski, Marc

    2013-08-07

    Abstract: Theoretical Particle Astrophysics The research carried out under this grant encompassed work on the early Universe, dark matter, and dark energy. We developed CMB probes for primordial baryon inhomogeneities, primordial non-Gaussianity, cosmic birefringence, gravitational lensing by density perturbations and gravitational waves, and departures from statistical isotropy. We studied the detectability of wiggles in the inflation potential in string-inspired inflation models. We studied novel dark-matter candidates and their phenomenology. This work helped advance the DoE's Cosmic Frontier (and also Energy and Intensity Frontiers) by finding synergies between a variety of different experimental efforts, by developing new searches, science targets, and analyses for existing/forthcoming experiments, and by generating ideas for new next-generation experiments.

  20. Bolometers as particle spectrometers

    NASA Astrophysics Data System (ADS)

    Stroke, H. H.; Artzner, G.; Coron, N.; Dambier, G.; Hansen, P. G.

    1986-02-01

    A spectrometer based on low-temperature calorimetry has been under development since 1983. The present detector, capable of recording individual alpha and beta particles and X-ray photons, is based on a composite diamond-germanium bolometer. The advantage of a composite bolometer is that it separates the absorption and detection functions. Diamond, as an absorber, is of particular advantage because of its low heat capacity and high thermal diffusivity. The goal is a theoretical energy resolution of a few eV at 0.1 K. Initial experiments at 1.3 K and 0.9 K, which give resolutions in the keV range, are still noise-limited. High-resolution applications, such as in X-ray astronomy and nuclear physics (in particular, neutron mass measurements) are foreseen.

  1. Particle processing technology

    NASA Astrophysics Data System (ADS)

    Sakka, Yoshio

    2014-02-01

    In recent years, there has been strong demand for the development of novel devices and equipment that support advanced industries including IT/semiconductors, the environment, energy and aerospace along with the achievement of higher efficiency and reduced environmental impact. Many studies have been conducted on the fabrication of innovative inorganic materials with novel individual properties and/or multifunctional properties including electrical, dielectric, thermal, optical, chemical and mechanical properties through the development of particle processing. The fundamental technologies that are key to realizing such materials are (i) the synthesis of nanoparticles with uniform composition and controlled crystallite size, (ii) the arrangement/assembly and controlled dispersion of nanoparticles with controlled particle size, (iii) the precise structural control at all levels from micrometer to nanometer order and (iv) the nanostructural design based on theoretical/experimental studies of the correlation between the local structure and the functions of interest. In particular, it is now understood that the application of an external stimulus, such as magnetic energy, electrical energy and/or stress, to a reaction field is effective in realizing advanced particle processing [1-3]. This special issue comprises 12 papers including three review papers. Among them, seven papers are concerned with phosphor particles, such as silicon, metals, Si3N4-related nitrides, rare-earth oxides, garnet oxides, rare-earth sulfur oxides and rare-earth hydroxides. In these papers, the effects of particle size, morphology, dispersion, surface states, dopant concentration and other factors on the optical properties of phosphor particles and their applications are discussed. These nanoparticles are classified as zero-dimensional materials. Carbon nanotubes (CNT) and graphene are well-known one-dimensional (1D) and two-dimensional (2D) materials, respectively. This special issue also

  2. Investigation of plasma particle interactions with variable particle sizes

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Laufer, Rene; Herdrich, Georg; Matthews, Lorin; Hyde, Truell

    2015-11-01

    In dusty plasmas, the dust particles are subjected to many forces of different origins. Both the gas and plasma directly affect the dust particles through electric fields, neutral drag, ion drag and thermophoretic forces, while the particles themselves interact with one another through a screened coulomb potential, which can be influenced by flowing ions. Recently, micron sized particles have been used as probes to analyze the electric fields in the plasma directly. A proper analysis of the resulting data requires a full understanding of the manner in which these forces couple to the dust particles. In most cases each of the forces exhibit unique characteristics, many of which are partially dependent on the particle size. In this study, five different particle sizes are used to investigate the forces resident in the sheath above the lower electrode of a GEC RF reference cell. The particles are tracked using a high-speed camera, yielding two-dimensional force maps allowing the force on the particles to be described as a polynomial series. It will be shown that the data collected can be analyzed to reveal information about the origins of the various forces. Support from the NSF and the DOE (award numbers PHY-1262031 and PHY-1414523) is gratefully acknowledged.

  3. Associated particle imaging (API)

    SciTech Connect

    1998-05-01

    Associated Particle Imaging (API) is an active neutron probe technique that provides a 3-D image with elemental composition of the material under interrogation, and so occupies a unique niche in the interrogation of unknown objects. The highly penetrating nature of neutrons enables API to provide detailed information about targets of interest that are hidden from view. Due to the isotropic nature of the induced reactions, radiation detectors can be set on the same side of the object as the neutron source, so that the object can be interrogated from a single side. At the heat of the system is a small generator that produces a continuous, monoenergetic flux of neutrons. By measuring the trajectory of coincident alpha particles that are produced as part of the process, the trajectory of the neutron can be inferred. Interactions between a neutron and the material in its path often produce a gamma ray whose energy is characteristic of that material. When the gamma ray is detected, its energy is measured and combined with the trajectory information to produce a 3-D image of the composition of the object being interrogated. During the course of API development, a number of improvements have been made. A new, more rugged sealed Tube Neutron Generator (STNG) has been designed and fabricated that is less susceptible to radiation damage and better able to withstand the rigors of fielding than earlier designs. A specialized high-voltage power supply for the STNG has also been designed and built. A complete package of software has been written for the tasks of system calibration, diagnostics and data acquisition and analysis. A portable system has been built and field tested, proving that API can be taken out of the lab and into real-world situations, and that its performance in the field is equal to that in the lab.

  4. Particle Dark Matter

    NASA Astrophysics Data System (ADS)

    Bertone, Gianfranco

    2013-11-01

    Part I. DM in Cosmology: 1. Particle dark matter G. Bertone and J. Silk; 2. Simulations of CDM haloes B. Moore and J. Diemand; 3. MW substructures J. Bullock, M. Kaplinghat and L. Strigari; 4. Gravitational lensing and dark matter Y. Mellier; 5. Dark matter at the centers of galaxies D. Merritt; 6. Modified gravity as an alternative to DM J. Bekenstein; Part II. Candidates: 7. DM production mechanisms G. Gelmini and P. Gondolo; 8. Supersymmetric DM candidates J. Ellis and K. Olive; 9. DM at the EW scale: non-SUSY candidates G. Servant; 10. Non-WIMP candidates J. L. Feng; 11. Axions P. Sikivie; 12. Sterile neutrinos M. Shaposhnikov; Part III. Colliders Searches: 13. SUSY searches at the LHC T. Plehn and G. Polesello; 14. SUSY DM at colliders M. Battaglia and M. E. Peskin; 15. Extra dimensions at the LHC K. Kong, K. Matchev and G. Servant; 16. SUSY tools F. Boudjema, J. Edsjö and P. Gondolo; Part IV. Direct Detection: 17. Direct detection of WIMPs D. G. Cerdeño and A. Green; 18. Annual modulation with NaI(Tl) R. Bernabei and P. Belli; 19. Particle DM and DAMA N. Fornengo; 20. Cryogenic detectors G. Gerbier and J. Gascon; 21. Liquid noble gases E. Aprile and L. Baudis; 22. Directional detectors N. Spooner; 23. Axion searches S. Asztalos; Part V. Indirect Detection and Astrophysical Constraints: 24. Gamma-rays L. Bergström and G. Bertone; 25. Neutrinos F. Halzen and D. Hooper; 26. Antimatter P. Salati, F. Donato and N. Fornengo; 27. Multi-wavelength S. Profumo and P. Ullio; 28. Dark matter and BBN K. Jedamzik and M. Pospelov; 29. Dark matter and stars G. Bertone; Appendix; References; Index.

  5. Nanocarpets for Trapping Microscopic Particles

    NASA Technical Reports Server (NTRS)

    Noca, Flavio; Chen, Fei; Hunt, Brian; Bronikowski, Michael; Hoenk, Michael; Kowalczyk, Robert; Choi, Daniel

    2004-01-01

    Nanocarpets that is, carpets of carbon nanotubes are undergoing development as means of trapping microscopic particles for scientific analysis. Examples of such particles include inorganic particles, pollen, bacteria, and spores. Nanocarpets can be characterized as scaled-down versions of ordinary macroscopic floor carpets, which trap dust and other particulate matter, albeit not purposefully. Nanocarpets can also be characterized as mimicking both the structure and the particle-trapping behavior of ciliated lung epithelia, the carbon nanotubes being analogous to cilia. Carbon nanotubes can easily be chemically functionalized for selective trapping of specific particles of interest. One could, alternatively, use such other three-dimensionally-structured materials as aerogels and activated carbon for the purposeful trapping of microscopic particles. However, nanocarpets offer important advantages over these alternative materials: (1) Nanocarpets are amenable to nonintrusive probing by optical means; and (2) Nanocarpets offer greater surface-to-volume ratios.

  6. Morphological details in bloodstain particles.

    PubMed

    De Wael, K; Lepot, L

    2015-01-01

    During the commission of crimes blood can be transferred to the clothing of the offender or on other crime related objects. Bloodstain particles are sub-millimetre sized flakes that are lost from dried bloodstains. The nature of these red particles is easily confirmed using spectroscopic methods. In casework, bloodstain particles showing highly detailed morphological features were observed. These provided a rationale for a series of experiments described in this work. It was found that the "largest" particles are shed from blood deposited on polyester and polyamide woven fabrics. No particles are lost from the stains made on absorbent fabrics and from those made on knitted fabrics. The morphological features observed in bloodstain particles can provide important information on the substrates from which they were lost.

  7. Fuzzy logic particle tracking velocimetry

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1993-01-01

    Fuzzy logic has proven to be a simple and robust method for process control. Instead of requiring a complex model of the system, a user defined rule base is used to control the process. In this paper the principles of fuzzy logic control are applied to Particle Tracking Velocimetry (PTV). Two frames of digitally recorded, single exposure particle imagery are used as input. The fuzzy processor uses the local particle displacement information to determine the correct particle tracks. Fuzzy PTV is an improvement over traditional PTV techniques which typically require a sequence (greater than 2) of image frames for accurately tracking particles. The fuzzy processor executes in software on a PC without the use of specialized array or fuzzy logic processors. A pair of sample input images with roughly 300 particle images each, results in more than 200 velocity vectors in under 8 seconds of processing time.

  8. Quark matter or new particles?

    NASA Technical Reports Server (NTRS)

    Michel, F. Curtis

    1988-01-01

    It has been argued that compression of nuclear matter to somewhat higher densities may lead to the formation of stable quark matter. A plausible alternative, which leads to radically new astrophysical scenarios, is that the stability of quark matter simply represents the stability of new particles compounded of quarks. A specific example is the SU(3)-symmetric version of the alpha particle, composed of spin-zero pairs of each of the baryon octet (an 'octet' particle).

  9. Particle cloud mixing in microgravity

    NASA Technical Reports Server (NTRS)

    Ross, H.; Facca, L.; Tangirala, V.; Berlad, A. L.

    1989-01-01

    Quasi-steady flame propagation through clouds of combustible particles requires quasi-steady transport properties and quasi-steady particle number density. Microgravity conditions may be employed to help achieve the conditions of quiescent, uniform clouds needed for such combustion studies. Joint experimental and theoretical NASA-UCSD studies were concerned with the use of acoustic, electrostatic, and other methods of dispersion of fuel particulates. Results of these studies are presented for particle clouds in long cylindrical tubes.

  10. Particle plasmons: Why shape matters

    NASA Astrophysics Data System (ADS)

    Barnes, William L.

    2016-08-01

    Simple analytic expressions for the polarizability of metallic nanoparticles are in wide use in the field of plasmonics, but their origins are not obvious. In this article, expressions for the polarizability of a particle are derived in the quasistatic limit in a manner that allows the physical origin of the terms to be clearly seen. The discussion is tutorial in nature, with particular attention given to the role of particle shape since this is a controlling factor in particle plasmon resonances.

  11. Quantitative wave-particle duality

    NASA Astrophysics Data System (ADS)

    Qureshi, Tabish

    2016-07-01

    The complementary wave and particle character of quantum objects (or quantons) was pointed out by Niels Bohr. This wave-particle duality, in the context of the two-slit experiment, is here described not just as two extreme cases of wave and particle characteristics, but in terms of quantitative measures of these characteristics, known to follow a duality relation. A very simple and intuitive derivation of a closely related duality relation is presented, which should be understandable to the introductory student.

  12. Thermophoresis of charged colloidal particles.

    PubMed

    Fayolle, Sébastien; Bickel, Thomas; Würger, Alois

    2008-04-01

    Thermally induced particle flow in a charged colloidal suspension is studied in a fluid-mechanical approach. The force density acting on the charged boundary layer is derived in detail. From Stokes' equation with no-slip boundary conditions at the particle surface, we obtain the particle drift velocity and the thermophoretic transport coefficients. The results are discussed in view of previous work and available experimental data.

  13. Photocatalytic/Magnetic Composite Particles

    NASA Technical Reports Server (NTRS)

    Wu, Chang-Yu; Goswami, Yogi; Garretson, Charles; Andino, Jean; Mazyck, David

    2007-01-01

    Photocatalytic/magnetic composite particles have been invented as improved means of exploiting established methods of photocatalysis for removal of chemical and biological pollutants from air and water. The photocatalytic components of the composite particles are formulated for high levels of photocatalytic activity, while the magnetic components make it possible to control the movements of the particles through the application of magnetic fields. The combination of photocatalytic and magnetic properties can be exploited in designing improved air- and water treatment reactors.

  14. A particle-particle collision strategy for arbitrarily shaped particles at low Stokes numbers

    NASA Astrophysics Data System (ADS)

    Daghooghi, Mohsen; Borazjani, Iman

    2016-11-01

    We present a collision strategy for particles with any general shape at low Stokes numbers. Conventional collision strategies rely upon a short -range repulsion force along particles centerline, which is a suitable choice for spherical particles and may not work for complex-shaped particles. In the present method, upon the collision of two particles, kinematics of particles are modified so that particles have zero relative velocity toward each other along the direction in which they have the minimum distance. The advantage of this novel technique is that it guaranties to prevent particles from overlapping without unrealistic bounce back at low Stokes numbers, which may occur if repulsive forces are used. This model is used to simulate sedimentation of many particles in a vertical channel and suspensions of non-spherical particles under simple shear flow. This work was supported by the American Chemical Society (ACS) Petroleum Research Fund (PRF) Grant Number 53099-DNI9. The computational resources were partly provided by the Center for Computational Research (CCR) at the University at Buffalo.

  15. Continuous flow dielectrophoretic particle concentrator

    SciTech Connect

    Cummings, Eric B.

    2007-04-17

    A continuous-flow filter/concentrator for separating and/or concentrating particles in a fluid is disclosed. The filter is a three-port device an inlet port, an filter port and a concentrate port. The filter separates particles into two streams by the ratio of their dielectrophoretic mobility to their electrokinetic, advective, or diffusive mobility if the dominant transport mechanism is electrokinesis, advection, or diffusion, respectively.Also disclosed is a device for separating and/or concentrating particles by dielectrophoretic trapping of the particles.

  16. Vacuum Friction in Rotating Particles

    SciTech Connect

    Manjavacas, A.; Garcia de Abajo, F. J.

    2010-09-10

    We study the frictional torque acting on particles rotating in empty space. At zero temperature, vacuum friction transforms mechanical energy into light emission and produces particle heating. However, particle cooling relative to the environment occurs at finite temperatures and low rotation velocities. Radiation emission is boosted and its spectrum significantly departed from a hot-body emission profile as the velocity increases. Stopping times ranging from hours to billions of years are predicted for materials, particle sizes, and temperatures accessible to experiment. Implications for the behavior of cosmic dust are discussed.

  17. Aging fingerprints in combustion particles

    NASA Astrophysics Data System (ADS)

    Zelenay, V.; Mooser, R.; Tritscher, T.; Křepelová, A.; Heringa, M. F.; Chirico, R.; Prévôt, A. S. H.; Weingartner, E.; Baltensperger, U.; Dommen, J.; Watts, B.; Raabe, J.; Huthwelker, T.; Ammann, M.

    2011-05-01

    Soot particles can significantly influence the Earth's climate by absorbing and scattering solar radiation as well as by acting as cloud condensation nuclei. However, despite their environmental (as well as economic and political) importance, the way these properties are affected by atmospheric processing is still a subject of discussion. In this work, soot particles emitted from two different cars, a EURO 2 transporter, a EURO 3 passenger vehicle, and a wood stove were investigated on a single-particle basis. The emitted exhaust, including the particulate and the gas phase, was processed in a smog chamber with artificial solar radiation. Single particle specimens of both unprocessed and aged soot were characterized using x-ray absorption spectroscopy and scanning electron microscopy. Comparison of the spectra from the unprocessed and aged soot particles revealed changes in the carbon functional group content, such as that of carboxylic carbon, which can be ascribed to both the condensation of secondary organic compounds on the soot particles and oxidation of primary soot particles upon photochemical aging. Changes in the morphology and size of the single soot particles were also observed upon aging. Furthermore, we show that the soot particles take up water in humid environments and that their water uptake capacity increases with photochemical aging.

  18. High field gradient particle accelerator

    DOEpatents

    Nation, John A.; Greenwald, Shlomo

    1989-01-01

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  19. High field gradient particle accelerator

    DOEpatents

    Nation, J.A.; Greenwald, S.

    1989-05-30

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  20. Patchy particles using colloidal caps

    NASA Astrophysics Data System (ADS)

    Middleton, Christine; Pine, David

    2015-03-01

    We present a method for making patchy particles functionalized with single stranded sticky end DNA only on their patches. This is done by adding ``spherical cap'' particles as patches to spherical colloids using the depletion interaction. The caps are then functionalized with single stranded DNA using copper-free click chemistry. Due to being attached only by depletion, the patches diffuse on the surface of the particle. The patchy particles can then interact with each other in a specific, directional way through the mobile, DNA functionalized patches.

  1. In Situ Solid Particle Generator

    NASA Technical Reports Server (NTRS)

    Agui, Juan H.; Vijayakumar, R.

    2013-01-01

    Particle seeding is a key diagnostic component of filter testing and flow imaging techniques. Typical particle generators rely on pressurized air or gas sources to propel the particles into the flow field. Other techniques involve liquid droplet atomizers. These conventional techniques have drawbacks that include challenging access to the flow field, flow and pressure disturbances to the investigated flow, and they are prohibitive in high-temperature, non-standard, extreme, and closed-system flow conditions and environments. In this concept, the particles are supplied directly within a flow environment. A particle sample cartridge containing the particles is positioned somewhere inside the flow field. The particles are ejected into the flow by mechanical brush/wiper feeding and sieving that takes place within the cartridge chamber. Some aspects of this concept are based on established material handling techniques, but they have not been used previously in the current configuration, in combination with flow seeding concepts, and in the current operational mode. Unlike other particle generation methods, this concept has control over the particle size range ejected, breaks up agglomerates, and is gravity-independent. This makes this device useful for testing in microgravity environments.

  2. Particle transport and deposition: basic physics of particle kinetics.

    PubMed

    Tsuda, Akira; Henry, Frank S; Butler, James P

    2013-10-01

    The human body interacts with the environment in many different ways. The lungs interact with the external environment through breathing. The enormously large surface area of the lung with its extremely thin air-blood barrier is exposed to particles suspended in the inhaled air. The particle-lung interaction may cause deleterious effects on health if the inhaled pollutant aerosols are toxic. Conversely, this interaction can be beneficial for disease treatment if the inhaled particles are therapeutic aerosolized drugs. In either case, an accurate estimation of dose and sites of deposition in the respiratory tract is fundamental to understanding subsequent biological response, and the basic physics of particle motion and engineering knowledge needed to understand these subjects is the topic of this article. A large portion of this article deals with three fundamental areas necessary to the understanding of particle transport and deposition in the respiratory tract. These are: (i) the physical characteristics of particles, (ii) particle behavior in gas flow, and (iii) gas-flow patterns in the respiratory tract. Other areas, such as particle transport in the developing lung and in the diseased lung are also considered. The article concludes with a summary and a brief discussion of areas of future research.

  3. Particle transport and deposition: basic physics of particle kinetics

    PubMed Central

    Tsuda, Akira; Henry, Frank S.; Butler, James P.

    2015-01-01

    The human body interacts with the environment in many different ways. The lungs interact with the external environment through breathing. The enormously large surface area of the lung with its extremely thin air-blood barrier is exposed to particles suspended in the inhaled air. Whereas the particle-lung interaction may cause deleterious effects on health if the inhaled pollutant aerosols are toxic, this interaction can be beneficial for disease treatment if the inhaled particles are therapeutic aerosolized drug. In either case, an accurate estimation of dose and sites of deposition in the respiratory tract is fundamental to understanding subsequent biological response, and the basic physics of particle motion and engineering knowledge needed to understand these subjects is the topic of this chapter. A large portion of this chapter deals with three fundamental areas necessary to the understanding of particle transport and deposition in the respiratory tract. These are: 1) the physical characteristics of particles, 2) particle behavior in gas flow, and 3) gas flow patterns in the respiratory tract. Other areas, such as particle transport in the developing lung and in the diseased lung are also considered. The chapter concludes with a summary and a brief discussion of areas of future research. PMID:24265235

  4. Particle Spectrometers for FRIB

    NASA Astrophysics Data System (ADS)

    Amthor, A. M.

    2014-09-01

    FRIB promises to dramatically expand the variety of nuclear systems available for direct experimental study by providing rates of many rare isotopes orders of magnitude higher than those currently available. A new generation of experimental systems, including new particle spectrometers will be critical to our ability to take full advantage of the scientific opportunities offered by FRIB. The High-Rigidity Spectrometer (HRS) will allow for experiments with the most neutron-rich and short-lived isotopes produced by in-flight fragmentation at FRIB. The bending capability of the HRS (8 Tm) matches to the rigidity for which rare isotopes are produced at the highest intensity in the FRIB fragment separator. The experimental program will be focused on nuclear structure and astrophysics, and allow for the use of other cutting-edge detection systems for gamma, neutron, and charged-particle detection. Stopped and reaccelerated beam studies will be an important compliment to in-flight techniques at FRIB, providing world-unique, high quality, intense rare isotope beams at low energies up to and beyond the Coulomb barrier--with the completion of ReA12--and serving many of the science goals of the broader facility, from nuclear structure and astrophysics to applications. Two specialized recoil spectrometers are being developed for studies with reaccelerated beams. SECAR, the Separator for Capture Reactions, will be built following ReA3, coupled to a windowless gas jet target, JENSA, and will focus on radiative capture reactions for astrophysics, particularly those needed to improve our understanding of novae and X-ray bursts. A recoil separator following ReA12 is proposed to address a variety of physics cases based on fusion-evaporation, Coulomb excitation, transfer, and deep-inelastic reactions by providing a large angular, momentum and charge state acceptance; a high mass resolving power; and the flexibility to couple to a variety of auxiliary detector systems. Two designs

  5. Multiswarm Particle Swarm Optimization with Transfer of the Best Particle

    PubMed Central

    Wei, Xiao-peng; Zhang, Jian-xia; Zhou, Dong-sheng; Zhang, Qiang

    2015-01-01

    We propose an improved algorithm, for a multiswarm particle swarm optimization with transfer of the best particle called BMPSO. In the proposed algorithm, we introduce parasitism into the standard particle swarm algorithm (PSO) in order to balance exploration and exploitation, as well as enhancing the capacity for global search to solve nonlinear optimization problems. First, the best particle guides other particles to prevent them from being trapped by local optima. We provide a detailed description of BMPSO. We also present a diversity analysis of the proposed BMPSO, which is explained based on the Sphere function. Finally, we tested the performance of the proposed algorithm with six standard test functions and an engineering problem. Compared with some other algorithms, the results showed that the proposed BMPSO performed better when applied to the test functions and the engineering problem. Furthermore, the proposed BMPSO can be applied to other nonlinear optimization problems. PMID:26345200

  6. Particle deposition in ventilation ducts

    SciTech Connect

    Sippola, Mark Raymond

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 μm were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the

  7. Single Particle Difraction at FLASH

    SciTech Connect

    Bogan, M.; Boutet, S.; Starodub, Dmitri; Decorwin-Martin, Philippe; Chapman, H.; Bajt, S.; Schulz, J.; Hajdu, Janos; Seibert, M.M.; Iwan, Bianca; Timneanu, Nicusor; Marchesini, Stefano; Barty, Anton; Benner, W.Henry; Frank, Matthias; Hau-Riege, Stefan P.; Woods, Bruce; Rohner, Urs; /Tofwerk AG, Thun

    2010-06-11

    Single-pulse coherent diffraction patterns have been collected from randomly injected single particles with a soft X-ray free-electron laser (FEL). The intense focused FEL pulse gives a high-resolution low-noise coherent diffraction pattern of the object before that object turns into a plasma and explodes. A diffraction pattern of a single particle will only be recorded when the particle arrival into the FEL interaction region coincides with FEL pulse arrival and detector integration. The properties of the experimental apparatus coinciding with these three events set the data acquisition rate. For our single particle FLASH diffraction imaging experiments: (1) an aerodynamic lens stack prepared a particle beam that consisted of particles moving at 150-200 m/s positioned randomly in space and time, (2) the 10 fs long FEL pulses were delivered at a fixed rate, and (3) the detector was set to integrate and readout once every two seconds. The effect of these experimental parameters on the rate of data acquisition using randomly injected particles will be discussed. Overall, the ultrashort FEL pulses do not set the limit of the data acquisition, more important is the effective interaction time of the particle crossing the FEL focus, the pulse sequence structure and the detector readout rate. Example diffraction patterns of randomly injected ellipsoidal iron oxide nanoparticles in different orientations are presented. This is the first single particle diffraction data set of identical particles in different orientations collected on a shot-to-shot basis. This data set will be used to test algorithms for recovering 3D structure from single particle diffraction.

  8. Astrophysical smooth particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Rosswog, Stephan

    2009-04-01

    The paper presents a detailed review of the smooth particle hydrodynamics (SPH) method with particular focus on its astrophysical applications. We start by introducing the basic ideas and concepts and thereby outline all ingredients that are necessary for a practical implementation of the method in a working SPH code. Much of SPH's success relies on its excellent conservation properties and therefore the numerical conservation of physical invariants receives much attention throughout this review. The self-consistent derivation of the SPH equations from the Lagrangian of an ideal fluid is the common theme of the remainder of the text. We derive a modern, Newtonian SPH formulation from the Lagrangian of an ideal fluid. It accounts for changes of the local resolution lengths which result in corrective, so-called "grad-h-terms". We extend this strategy to special relativity for which we derive the corresponding grad-h equation set. The variational approach is further applied to a general-relativistic fluid evolving in a fixed, curved background space-time. Particular care is taken to explicitly derive all relevant equations in a coherent way.

  9. Particle pressures in fluidized beds

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C.; Potapov, A.V.

    1992-01-01

    This is an experimental project to make detailed measurements of the particle pressures generated in fluidized beds. The focus lies in two principle areas: (1) the particle pressure distribution around single bubbles rising in a two-dimensional gas-fluidized bed and (2) the particle pressures measured in liquid-fluidized beds. This first year has largely been to constructing the experiments The design of the particle pressure probe has been improved and tested. A two-dimensional gas-fluidized bed has been constructed in order to measure the particle pressure generated around injected bubbles. The probe is also being adapted to work in a liquid fluidized bed. Finally, a two-dimensional liquid fluidized bed is also under construction. Preliminary measurements show that the majority of the particle pressures are generated in the wake of a bubble. However, the particle pressures generated in the liquid bed appear to be extremely small. Finally, while not directly associated with the particle pressure studies, some NERSC supercomputer time was granted alongside this project. This is being used to make large scale computer simulation of the flow of granular materials in hoppers.

  10. Particle behavior in thermal plasmas

    SciTech Connect

    Pfender, E. )

    1989-03-01

    In this overview, effects exerted on the motion and on heat and mass transfer of particulates injected into a thermal plasma are discussed, including an assessment of their relative importance in the context of thermal plasma processing of materials. Results of computer experiments are shown for particle sizes ranging from 5-50 {mu}m, and for alumina and tungsten as sample materials. The results indicate that (i) the correction terms required for the viscous drag and the convective heat transfer due to strongly varying properties are the most important factors; (ii) noncontinuum effects are important for particle sizes < 10 {mu}m at atmospheric pressure, and these effects will be enhanced for smaller particles and/or reduced pressures; (iii) the Basset history term is negligible, unless relatively large and light particles are considered over long processing distances; (iv) thermophoresis is not crucial for the injection of particles into thermal plasmas; (v) turbulent dispersion becomes important for particle < 10 {mu}m in diameter; and (vi) vaporization describes a different particle heating history than that of the evaporation process which, however, is not a critical control mechanism for interphase mass transfer of particles injected into thermal plasmas.

  11. Chaotic behavior of channeling particles.

    PubMed

    Chen, Ling; Kaloyeros, Alain E.; Wang, Guang-Hou

    1994-03-01

    Channeling describes the collimated motion of energetic charged particles along the lattice plane or axis in a crystal. The energetic particles are steered through the channels formed by strings of atomic constituents in the lattice. In the case of planar channeling, the motion of a charged particle between the atomic planes can be periodic or quasiperiodic, such as a simple oscillatory motion in the transverse direction. In practice, however, the periodic motion of the channeling particles can be accompanied by an irregular, chaotic behavior. In this paper, the Moliere potential, which is considered as a good analytical approximation for the interaction of channeling particles with the rows of atoms in the lattice, is used to simulate the channeling behavior of positively charged particles in a tungsten (100) crystal plane. By appropriate selection of channeling parameters, such as the projectile energy E(0) and incident angle psi(0), the transition of channeling particles from regular to chaotic motion is demonstrated. It is argued that the fine structures that appear in the angular scan channeling experiments are due to the particles' chaotic motion.

  12. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Vogt, R. E.; Buffington, A.; Davis, L., Jr.; Stone, E. C.

    1980-01-01

    The astrophysical aspects of cosmic and gamma rays and the radiation environment of the Earth and other planets investigated by means of energetic particle detector systems flown on spacecraft and balloons are discussed. The theory of particles and fields in space is also addressed with particular emphasis on models of Saturn's magnetic field.

  13. Particle production in Ekpyrotic scenarios

    SciTech Connect

    Hipólito-Ricaldi, W.S.; Brandenberger, Robert; Ferreira, Elisa G.M.; Graef, L.L.

    2016-11-09

    We consider Parker particle production in the Ekpyrotic scenario (in particular in the New Ekpyrotic model) and show that the density of particles produced by the end of the phase of Ekpyrotic contraction can be sufficient to lead to a hot state of matter after the bounce. Hence, no separate reheating mechanism is necessary.

  14. The Particle--Motion Problem.

    ERIC Educational Resources Information Center

    Demana, Franklin; Waits, Bert K.

    1993-01-01

    Discusses solutions to real-world linear particle-motion problems using graphing calculators to simulate the motion and traditional analytic methods of calculus. Applications include (1) changing circular or curvilinear motion into linear motion and (2) linear particle accelerators in physics. (MDH)

  15. The Particle Theory of Matter

    ERIC Educational Resources Information Center

    Widick, Paul R.

    1969-01-01

    Described are activities that are designed to help elementary children understand the possibility of the particle theory of matter. Children work with beads, marbles, B-B shot and sand; by mixing these materials and others they are led to see that it is highly possible for the existence of particles which are not visible. (BR)

  16. Build Your Own Particle Sensor

    EPA Science Inventory

    This is an information packet explaining an educational outreach activity, where the participant does some simple electronics with low cost components to build a particle sensor that can turn one to three small lights on based upon the detected concentration of particles.

  17. High Energy Particles in Tokamaks

    SciTech Connect

    White, R. B.

    2008-05-14

    This lecture covers the derivation of guiding center equations in a tokamak, orbit classification, the effect of magnetic perturbations and ripple, the interaction of particles with magnetohydrodynamic modes, including passing particle resonance, toroidal Alfven mode drive and saturation, the fishbone mode, and sawtooth stabilization.

  18. Superconducting transmission line particle detector

    DOEpatents

    Gray, K.E.

    1988-07-28

    A microvertex particle detector for use in a high energy physic collider including a plurality of parallel superconducting thin film strips separated from a superconducting ground plane by an insulating layer to form a plurality of superconducting waveguides. The microvertex particle detector indicates passage of a charged subatomic particle by measuring a voltage pulse measured across a superconducting waveguide caused by the transition of the superconducting thin film strip from a superconducting to a non- superconducting state in response to the passage of a charged particle. A plurality of superconducting thin film strips in two orthogonal planes plus the slow electromagnetic wave propagating in a superconducting transmission line are used to resolve N/sup 2/ ambiguity of charged particle events. 6 figs.

  19. Dynamics of Radiation Belt Particles

    NASA Astrophysics Data System (ADS)

    Ukhorskiy, A. Y.; Sitnov, M. I.

    2013-11-01

    This paper reviews basic concepts of particle dynamics underlying theoretical aspect of radiation belt modeling and data analysis. We outline the theory of adiabatic invariants of quasiperiodic Hamiltonian systems and derive the invariants of particle motion trapped in the radiation belts. We discuss how the nonlinearity of resonant interaction of particles with small-amplitude plasma waves, ubiquitous across the inner magnetosphere, can make particle motion stochastic. Long-term evolution of a stochastic system can be described by the Fokker-Plank (diffusion) equation. We derive the kinetic equation of particle diffusion in the invariant space and discuss its limitations and associated challenges which need to be addressed in forthcoming radiation belt models and data analysis.

  20. Selective encapsulation by Janus particles

    SciTech Connect

    Li, Wei; Ruth, Donovan; Gunton, James D.; Rickman, Jeffrey M.

    2015-06-28

    We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored, as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.

  1. Particle sizer and DNA sequencer

    DOEpatents

    Olivares, Jose A.; Stark, Peter C.

    2005-09-13

    An electrophoretic device separates and detects particles such as DNA fragments, proteins, and the like. The device has a capillary which is coated with a coating with a low refractive index such as Teflon.RTM. AF. A sample of particles is fluorescently labeled and injected into the capillary. The capillary is filled with an electrolyte buffer solution. An electrical field is applied across the capillary causing the particles to migrate from a first end of the capillary to a second end of the capillary. A detector light beam is then scanned along the length of the capillary to detect the location of the separated particles. The device is amenable to a high throughput system by providing additional capillaries. The device can also be used to determine the actual size of the particles and for DNA sequencing.

  2. Particle production in inhomogeneous cosmologies

    SciTech Connect

    Cespedes, J.; Verdaguer, E. )

    1990-02-15

    A perturbative evaluation of the {ital S} matrix is used to compute the production of particles in an expanding flat Friedmann-Robertson-Walker universe in the presence of small inhomogeneities. We first consider the production of massless conformally coupled and weakly nonconformally coupled particles, obtaining known results, and then we consider the production of massive particles. The production of massive particles cannot be treated only perturbatively and a method is proposed to compute this in general. The pair-production probability is computed using two different, but related, methods: in one we directly evaluate the number of particles produced and in the other we concentrate mainly on the vacuum-to-vacuum or vacuum persistence amplitude.

  3. Superconducting transmission line particle detector

    DOEpatents

    Gray, Kenneth E.

    1989-01-01

    A microvertex particle detector for use in a high energy physic collider including a plurality of parallel superconducting thin film strips separated from a superconducting ground plane by an insulating layer to form a plurality of superconducting waveguides. The microvertex particle detector indicates passage of a charged subatomic particle by measuring a voltage pulse measured across a superconducting waveguide caused by the transition of the superconducting thin film strip from a superconducting to a non-superconducting state in response to the passage of a charged particle. A plurality of superconducting thin film strips in two orthogonal planes plus the slow electromagnetic wave propogating in a superconducting transmission line are used to resolve N.sup.2 ambiguity of charged particle events.

  4. Nonlinear Particle Acceleration and Thermal Particles in GRB Afterglows

    NASA Astrophysics Data System (ADS)

    Warren, Donald C.; Ellison, Donald C.; Barkov, Maxim V.; Nagataki, Shigehiro

    2017-02-01

    The standard model for GRB afterglow emission treats the accelerated electron population as a simple power law, N(E)\\propto {E}-p for p≳ 2. However, in standard Fermi shock acceleration, a substantial fraction of the swept-up particles do not enter the acceleration process at all. Additionally, if acceleration is efficient, then the nonlinear back-reaction of accelerated particles on the shock structure modifies the shape of the nonthermal tail of the particle spectra. Both of these modifications to the standard synchrotron afterglow impact the luminosity, spectra, and temporal variation of the afterglow. To examine the effects of including thermal particles and nonlinear particle acceleration on afterglow emission, we follow a hydrodynamical model for an afterglow jet and simulate acceleration at numerous points during the evolution. When thermal particles are included, we find that the electron population is at no time well fitted by a single power law, though the highest-energy electrons are; if the acceleration is efficient, then the power-law region is even smaller. Our model predicts hard–soft–hard spectral evolution at X-ray energies, as well as an uncoupled X-ray and optical light curve. Additionally, we show that including emission from thermal particles has drastic effects (increases by factors of 100 and 30, respectively) on the observed flux at optical and GeV energies. This enhancement of GeV emission makes afterglow detections by future γ-ray observatories, such as CTA, very likely.

  5. Particle beam fusion

    SciTech Connect

    1980-12-31

    Today, in keeping with Sandia Laboratories` designation by the Department of Energy as the lead laboratory for the pulsed power approach to fusion, its efforts include major research activities and the construction of new facilities at its Albuquerque site. Additionally, in its capacity as lead laboratory, Sandia coordinates DOE-supported pulsed power fusion work at other government operated laboratories, with industrial contractors, and universities. The beginning of Sandia`s involvement in developing fusion power was an outgrowth of its contributions to the nation`s nuclear weapon program. The Laboratories` work in the early 1960`s emphasized the use of pulsed radiation environments to test the resistance of US nuclear weapons to enemy nuclear bursts. A careful study of options for fusion power indicated that Sandia`s expertise in the pulsed power field could provide a powerful match to ignite fusion fuel. Although creating test environments is an achieved goal of Sandia`s overall program, this work and other military tasks protected by appropriate security regulations will continue, making full use of the same pulsed power technology and accelerators as the fusion-for-energy program. Major goals of Sandia`s fusion program including the following: (1) complete a particle accelerator to deliver sufficient beam energy for igniting fusion targets; (2) obtain net energy gain, this goal would provide fusion energy output in excess of energy stored in the accelerator; (3) develop a technology base for the repetitive ignition of pellets in a power reactor. After accomplishing these goals, the technology will be introduced to the nation`s commercial sector.

  6. Focusing particle concentrator with application to ultrafine particles

    DOEpatents

    Hering, Susanne; Lewis, Gregory; Spielman, Steven R.

    2013-06-11

    Technology is presented for the high efficiency concentration of fine and ultrafine airborne particles into a small fraction of the sampled airflow by condensational enlargement, aerodynamic focusing and flow separation. A nozzle concentrator structure including an acceleration nozzle with a flow extraction structure may be coupled to a containment vessel. The containment vessel may include a water condensation growth tube to facilitate the concentration of ultrafine particles. The containment vessel may further include a separate carrier flow introduced at the center of the sampled flow, upstream of the acceleration nozzle of the nozzle concentrator to facilitate the separation of particle and vapor constituents.

  7. Electrostatic wire stabilizing a charged particle beam

    DOEpatents

    Prono, D.S.; Caporaso, G.J.; Briggs, R.J.

    1983-03-21

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  8. Sampling of respirable isocyanate particles.

    PubMed

    Gylestam, Daniel; Gustavsson, Marcus; Karlsson, Daniel; Dalene, Marianne; Skarping, Gunnar

    2014-04-01

    An advanced design of a denuder impactor (DI) sampler has been developed for characterization of possible airborne isocyanate exposure in different particle size fractions. The sampler is equipped with 12 different parallel denuder tubes, 4 impaction stages with the cut-off values (d50) of: 9.5, 4, 2.5 and 1 µm, and an end filter that collects particles < 1 µm. All collecting parts were impregnated with di-n-butylamine DBA as the reagent in a mixture with acetic acid. The performance of the DI sampler was studied on a standard atmosphere containing gas and particulate isocyanates. The isocyanate atmosphere was generated by liquid permeation of 2,4-, 2,6-Toluene Diisocyanate (TDI), 1,6-Hexamethylene Diisocyanate (HDI) and Isophorone Diisocyanate (IPDI). 4,4'-Methylene Diphenyl Diisocyanate (MDI) particles were generated by heating of technical MDI and condensing the mixture of gas and particle-borne MDI in an atmosphere containing mixed salt particles. The study was performed in a 0.85 m3 environmental chamber with stainless steel walls. With the advancement of the DI sampler it is now possible to collect isocyanate particle samples for up to 320 min. The performance of the DI sampler is essentially unaffected by the humidity. The DI sampler and the ASSET EZ4-NCO sampler (Sigma-Aldrich/Supelco, Bellefonte, PA, USA) gave similar results. Sample losses within the DI sampler are low. In the environmental chamber it was observed that the particle distribution may be affected by the humidity and ageing. A scanning mobility particle sizer (SMPS) was used to separate a flow of selected fractions containing MDI particles from mixed MDI and salt particles. The particle-size distribution had a maximum at about 300 nm, but later in the environmental chamber 1 µm dominated. The distribution was very different as compared to with only NaCl or MDI present. The biological relevance for studying isocyanate nano particles is significant as these have the possibility to reach the

  9. GPU-enabled particle-particle particle-tree scheme for simulating dense stellar cluster system

    NASA Astrophysics Data System (ADS)

    Iwasawa, Masaki; Portegies Zwart, Simon; Makino, Junichiro

    2015-07-01

    We describe the implementation and performance of the (Particle-Particle Particle-Tree) scheme for simulating dense stellar systems. In , the force experienced by a particle is split into short-range and long-range contributions. Short-range forces are evaluated by direct summation and integrated with the fourth order Hermite predictor-corrector method with the block timesteps. For long-range forces, we use a combination of the Barnes-Hut tree code and the leapfrog integrator. The tree part of our simulation environment is accelerated using graphical processing units (GPU), whereas the direct summation is carried out on the host CPU. Our code gives excellent performance and accuracy for star cluster simulations with a large number of particles even when the core size of the star cluster is small.

  10. Negative Numbers and Antimatter Particles

    NASA Astrophysics Data System (ADS)

    Tsan, Ung Chan

    Dirac's equation states that an electron implies the existence of an antielectron with the same mass (more generally same arithmetic properties) and opposite charge (more generally opposite algebraic properties). Subsequent observation of antielectron validated this concept. This statement can be extended to all matter particles; observation of antiproton, antineutron, antideuton … is in complete agreement with this view. Recently antihypertriton was observed and 38 atoms of antihydrogen were trapped. This opens the path for use in precise testing of nature's fundamental symmetries. The symmetric properties of a matter particle and its mirror antimatter particle seem to be well established. Interactions operate on matter particles and antimatter particles as well. Conservation of matter parallels addition operating on positive and negative numbers. Without antimatter particles, interactions of the Standard Model (electromagnetism, strong interaction and weak interaction) cannot have the structure of group. Antimatter particles are characterized by negative baryonic number A or/and negative leptonic number L. Materialization and annihilation obey conservation of A and L (associated to all known interactions), explaining why from pure energy (A = 0, L = 0) one can only obtain a pair of matter particle antimatter particle — electron antielectron, proton and antiproton — via materialization where the mass of a pair of particle antiparticle gives back to pure energy with annihilation. These two mechanisms cannot change the difference in the number of matter particles and antimatter particles. Thus from pure energy only a perfectly symmetric (in number) universe could be generated as proposed by Dirac but observation showed that our universe is not symmetric, it is a matter universe which is nevertheless neutral. Fall of reflection symmetries shattered the prejudice that there is no way to define in an absolute way right and left or matter and antimatter

  11. A single particle energies

    SciTech Connect

    Bodmer, A.R. |; Usmani, Q.N.; Sami, M.

    1993-09-01

    We consider the binding energies of {Lambda} hypernuclei (HN), in particular the single-particle (s.p.) energy data, which have been obtained for a wide range of HN with mass numbers A {le} 89 and for orbital angular momenta {ell}{sub {Lambda}} {le} 4. We briefly review some of the relevant properties of A hypernuclei. These are nuclei {sub {Lambda}}{sup A}Z with baryon number A in which a single {Lambda} hyperon (baryon number = 1) is bound to an ordinary nucleus {sup A}Z consisting of A - 1 nucleons = Z protons + N neutrons. The {Lambda} hyperon is neutral, has spin 1/2, strangeness S = {minus}1, isospin I = O and a mass M{sub {Lambda}} = 1116 MeV/c{sup 2}. Although the {Lambda} interacts with a nucleon, its interaction is only about half as strong as that between two nucleons, and thus very roughly V{sub {Lambda}N} {approx} 0.5 V{sub NN}. As a result, the two-body {Lambda}N system is unbound, and the lightest bound HN is the three-body hypertriton {sub {Lambda}}{sup 3}H in which the {Lambda} is bound to a deuteron with the {Lambda}-d separation energy being only {approx} 0.1 MeV corresponding to an exponential tail of radius {approx} 15 fm! In strong interactions the strangeness S is of course conserved, and the {Lambda} is distinct from the nucleons. In a HN strangeness changes only in the weak decays of the {Lambda} which can decay either via ``free`` pionic decay {Lambda} {yields} N + {pi} or via induced decay {Lambda} + N {yields} N + N which is only possible in the presence of nucleons. Because of the small energy release the pionic decay is strongly suppressed in all but the lightest HN and the induced decay dominates. However, the weak decay lifetime {approx} 10{sup {minus}10}s is in fact close to the lifetime of a free {Lambda}. Since this is much longer than the strong interaction time {approx} 10{sup {minus}22}s we can ignore the weak interactions when considering the binding of HN, just as for ordinary nuclei.

  12. Primary particles in ship emissions

    NASA Astrophysics Data System (ADS)

    Fridell, Erik; Steen, Erica; Peterson, Kjell

    There is not much data available regarding particle emissions from ships. In this study the size distributions of particles in ship exhaust from three different ships in normal operational conditions were studied using a cascade impactor. The ships were equipped with slow- or medium-speed main engines and medium-speed auxiliary engines. The fuel was residual oil except for the auxiliary engines on one ship which used marine diesel. Large emissions and a dependence of the sulfur content in the fuel were observed. High amounts of relatively large particles (around 8 μm) were observed. These are attributed to re-entrained soot particles from walls in the engine systems. A strong variation between different ships was observed for the particle-size distribution and for the dependence on engine load. The particle emissions were found to be reduced to about half, over the whole size range, by an SCR system. The total particle emission, measured after dilution, varied between 0.3 and 3 g kW h -1 depending on load, fuel and engine.

  13. Detector for Particle Surface Contamination

    NASA Technical Reports Server (NTRS)

    Mogan, Paul A. (Inventor); Schwindt, Christian J. (Inventor); Mattson, Carl B. (Inventor)

    1999-01-01

    A system and method for detecting and quantizing particle fallout contamination particles which are collected on a transparent disk or other surface employs an optical detector, such as a CCD camera, to obtain images of the disk and a computer for analyzing the images. From the images, the computer detects, counts and sizes particles collected on the disk The computer also determines, through comparison to previously analyzed images, the particle fallout rate, and generates an alarm or other indication if the rate exceeds a maximum allowable value. The detector and disk are disposed in a housing having an aperture formed therein for defining the area on the surface of the disk which is exposed to the particle fallout. A light source is provided for evenly illuminating the disk. A first drive motor slowly rotates the disk to increase the amount of its surface area which is exposed through the aperture to the particle fallout. A second motor is also provided for incrementally scanning the disk in a radial direction back and forth over the camera so that the camera eventually obtains images of the entire surface of the disk which is exposed to the particle fallout.

  14. Vortex Cores of Inertial Particles.

    PubMed

    Günther, Tobias; Theisel, Holger

    2014-12-01

    The cores of massless, swirling particle motion are an indicator for vortex-like behavior in vector fields and to this end, a number of coreline extractors have been proposed in the literature. Though, many practical applications go beyond the study of the vector field. Instead, engineers seek to understand the behavior of inertial particles moving therein, for instance in sediment transport, helicopter brownout and pulverized coal combustion. In this paper, we present two strategies for the extraction of the corelines that inertial particles swirl around, which depend on particle density, particle diameter, fluid viscosity and gravity. The first is to deduce the local swirling behavior from the autonomous inertial motion ODE, which eventually reduces to a parallel vectors operation. For the second strategy, we use a particle density estimation to locate inertial attractors. With this, we are able to extract the cores of swirling inertial particle motion for both steady and unsteady 3D vector fields. We demonstrate our techniques in a number of benchmark data sets, and elaborate on the relation to traditional massless corelines.

  15. Solar flares and energetic particles.

    PubMed

    Vilmer, Nicole

    2012-07-13

    Solar flares are now observed at all wavelengths from γ-rays to decametre radio waves. They are commonly associated with efficient production of energetic particles at all energies. These particles play a major role in the active Sun because they contain a large amount of the energy released during flares. Energetic electrons and ions interact with the solar atmosphere and produce high-energy X-rays and γ-rays. Energetic particles can also escape to the corona and interplanetary medium, produce radio emissions (electrons) and may eventually reach the Earth's orbit. I shall review here the available information on energetic particles provided by X-ray/γ-ray observations, with particular emphasis on the results obtained recently by the mission Reuven Ramaty High-Energy Solar Spectroscopic Imager. I shall also illustrate how radio observations contribute to our understanding of the electron acceleration sites and to our knowledge on the origin and propagation of energetic particles in the interplanetary medium. I shall finally briefly review some recent progress in the theories of particle acceleration in solar flares and comment on the still challenging issue of connecting particle acceleration processes to the topology of the complex magnetic structures present in the corona.

  16. Particle-wall tribology of slippery hydrogel particle suspensions.

    PubMed

    Shewan, Heather M; Stokes, Jason R; Cloitre, Michel

    2017-03-08

    Slip is an important phenomenon that occurs during the flow of yield stress fluids like soft materials and pastes. Densely packed suspensions of hydrogel microparticles are used to show that slip is governed by the tribological interactions occurring between the samples and shearing surfaces. Both attractive/repulsive interactions between the dispersed particles and surface, as well as the viscoelasticity of the suspension, are found to play key roles in slip occurring within rheometric flows. We specifically discover that for two completely different sets of microgels, the sliding stress at which slip occurs scales with both the modulus of the particles and the bulk suspension modulus. This suggests that hysteresis losses within the viscoelastic particles contribute to friction forces and thus slip at the particle-surface tribo-contact. It is also found that slip during large amplitude oscillatory shear and steady shear flows share the same generic features.

  17. Particle Detectors Subatomic Bomb Squad

    SciTech Connect

    Lincoln, Don

    2014-08-29

    The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

  18. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1987-01-01

    The astrophysical aspects of cosmic rays and gamma rays and the radiation and electromagnetic field environment of the Earth and other planets are investigated. These investigations are carried out by means of energetic particle and photon detector systems flown on spacecraft and balloons. Particle astrophysics is directed toward the investigation of galactic, solar, interplanetary, and planetary energetic particles and plasmas. The emphasis is on precision measurements with high resolution in charge, mass, and energy. Gamma ray research is directed toward the investigation of galactic, extragalactic, and solar gamma rays with spectrometers of high angular resolution and moderate energy resolution carried on spacecraft and balloons.

  19. Particle transport in planetary magnetospheres

    SciTech Connect

    Birmingham, T.J.

    1984-11-01

    Particle energization in Earth's and Jupiter's magnetospheres is discussed. Understanding of the large scale magnetic and electric fields in which charged particles move is reviewed. Orbit theory in the adiabatic approximation is sketched. General conditions for adiabatic breakdown at each of three levels of periodicity are presented. High energy losses and lower energy sources argue for the existence of magnetospheric accelerations. Nonadiabatic acceleration processes are mentioned. Slow diffusive energization by particle interactions with electromagnetic fluctuations is outlined. This mechanism seems adequate at Earth but, operating alone, is unconvincing for Jupiter. Adding spatial diffusion in the radially distended Jovian magnetodisk may resolve the difficulty. (ESA)

  20. Particle Detectors Subatomic Bomb Squad

    ScienceCinema

    Lincoln, Don

    2016-07-12

    The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

  1. Fog dispersion. [charged particle technique

    NASA Technical Reports Server (NTRS)

    Christensen, L. S.; Frost, W.

    1980-01-01

    The concept of using the charged particle technique to disperse warm fog at airports is investigated and compared with other techniques. The charged particle technique shows potential for warm fog dispersal, but experimental verification of several significant parameters, such as particle mobility and charge density, is needed. Seeding and helicopter downwash techniques are also effective for warm fog disperals, but presently are not believed to be viable techniques for routine airport operations. Thermal systems are currently used at a few overseas airports; however, they are expensive and pose potential environmental problems.

  2. Particle displacement tracking for PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1990-01-01

    A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

  3. Condensation Particle Counter Instrument Handbook

    SciTech Connect

    Kuang, C.

    2016-02-01

    The Model 3772 CPC is a compact, rugged, and full-featured instrument that detects airborne particles down to 10 nm in diameter, at an aerosol flow rate of 1.0 lpm, over a concentration range from 0 to 1x104 #/cc. This CPC is ideally suited for applications without high concentration measurements, such as basic aerosol research, filter and air-cleaner testing, particle counter calibrations, environmental monitoring, mobile aerosol studies, particle shedding and component testing, and atmospheric and climate studies.

  4. A Lightweight Particle Deposition System for Particle Resuspension Studies

    NASA Astrophysics Data System (ADS)

    Degraw, Jason; Cimbala, John

    2007-11-01

    Experimental studies of particle resuspension often require that particles be deposited in a localized area in a repeatable manner. A system has been designed for this purpose that is lightweight in both mass and complexity -- attributes which are both highly desirable. The low mass of the system allows for accurate determination of the mass of particulate matter placed inside the system (via tare weighing), and the low complexity of the system makes it easy to use. The device is a piston-cylinder apparatus made of plastic, and is therefore inexpensive to build, easy to clean, and readily disposable. Rapid upward movement of the piston draws air into the cylinder through small ports placed around the perimeter of the cylinder. The injected air aerosolizes particulate matter placed in the ports, and then the particles are allowed to settle onto the substrate. The device enables the localized deposition of particles without much lost material, allowing for more frugal and careful use of allergen- containing particulate matter (some of which require a great deal of time and effort to produce). Our previous system would deposit about 15-20% of the particles in the desired location (typically a small region of a flooring sample), while the new system is able to deposit more than 25-30% of the particles in the desired location with considerably less waste.

  5. Sources of zodiacal dust particles

    NASA Astrophysics Data System (ADS)

    Ipatov, S. I.; Mather, J. C.

    2007-08-01

    The orbital evolution of dust particles produced by asteroids, comets, and trans- Neptunian objects was integrated [1-3]. Analysis of results of these integrations testify in favor of a considerable fraction of particles produced by comets among overall zodiacal dust particles, but it does not contradict to >30% of asteroidal dust needed for explanation of formation of dust bands. Fractions of asteroidal particles, particles originating beyond Jupiter's orbit (including trans-Neptunian particles), and cometary particles originating inside of Jupiter's orbit are estimated to be about 1/3 each, with a possible deviation from 1/3 up to 0.1-0.2. Comparison of the plots of the number density vs. the distance R from the Sun obtained for particles produced by different small bodies with the plots based on observations shows that asteroidal and trans- Neptunian particles alone can not explain the observed almost constant number density at R ∼3-18 AU and a lot of particles must be produced by comets at R ∼5-10 AU [2-3]. Comparison of the WHAM (Wisconsin H-Alpha Mapper spectrometer) observations of spectra of zodiacal light with our models showed [4-5] that a significant fraction of particles produced by short-period comets is required to fit the observations of the width and velocity of the Mg I line. Comparison of the observations of the number density inside Jupiter's orbit with the number density of particles produced by different small bodies leads to the same conclusion about a considerable fraction of cometary particles. This comparison does not make limitations on cometary particles produced beyond Jupiter's orbit, but it shows that the fraction of particles produced by Encke-type comets (with eccentricities ∼0.8-0.9) does not exceed 0.15 of the overall population. The estimated fraction of particles produced by long-period and Halley-type comets among zodiacal dust also does not exceed 0.1-0.15. Though trans-Neptunian particles fit different observations of

  6. Inclusive Focus Particles in English and Korean

    ERIC Educational Resources Information Center

    Kang, Sang-gu

    2011-01-01

    When discussing focus particles, it has been common practice to rely on the dichotomy of inclusive vs. exclusive particles, "a la" Konig (1991). Inclusive focus particles are often further divided into scalar particles, such as "also", "too", and "either", and non-scalar particles, such as "even". In this thesis, I advance a comparative analysis…

  7. Matter and Interactions: A Particle Physics Perspective

    ERIC Educational Resources Information Center

    Organtini, Giovanni

    2011-01-01

    In classical mechanics, matter and fields are completely separated; matter interacts with fields. For particle physicists this is not the case; both matter and fields are represented by particles. Fundamental interactions are mediated by particles exchanged between matter particles. In this article we explain why particle physicists believe in…

  8. Particle adhesion in powder coating

    SciTech Connect

    Mazumder, M.K.; Wankum, D.L.; Knutson, M.; Williams, S.; Banerjee, S.

    1996-12-31

    Electrostatic powder coating is a widely used industrial painting process. It has three major advantages: (1) it provides high quality durable finish, (2) the process is environmentally friendly and does not require the use of organic solvents, and (3) it is economically competitive. The adhesion of electrostatically deposited polymer paint particles on the grounded conducting substrate depends upon many parameters: (a) particle size and shape distributions, (b) electrostatic charge distributions, (c) electrical resistivity, (d) dielectric strength of the particles, (e) thickness of the powder film, (f) presence and severity of the back corona, and (g) the conductivity and surface properties of the substrate. The authors present a model on the forces of deposition and adhesion of corona charged particles on conducting substrates.

  9. Particle detection systems and methods

    DOEpatents

    Morris, Christopher L.; Makela, Mark F.

    2010-05-11

    Techniques, apparatus and systems for detecting particles such as muons and neutrons. In one implementation, a particle detection system employs a plurality of drift cells, which can be for example sealed gas-filled drift tubes, arranged on sides of a volume to be scanned to track incoming and outgoing charged particles, such as cosmic ray-produced muons. The drift cells can include a neutron sensitive medium to enable concurrent counting of neutrons. The system can selectively detect devices or materials, such as iron, lead, gold, uranium, plutonium, and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can concurrently detect any unshielded neutron sources occupying the volume from neutrons emitted therefrom. If necessary, the drift cells can be used to also detect gamma rays. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

  10. Study of heavy flavored particles

    SciTech Connect

    Nemati, Bijan

    1991-01-01

    This report discusses progress on the following topics: time-of- flight system; charmed baryon production and decays; D decays to baryons; measurement of sigma plus particles magnetic moments; and strong interaction coupling. (LSP)

  11. Velocities of Zodiacal Dust Particles

    NASA Astrophysics Data System (ADS)

    Ipatov, S. I.; Kutyrev, A. S.; Madsen, G. J.; Mather, J. C.; Moseley, S. H.; Reynolds, R. J.

    2005-09-01

    Ipatov et al. (2005, LPSC, 1266) compared the observational plots of the zodiacal light spectrum near the solar Mg Iλ 5184 absorption line (Reynolds, Madsen and Moseley, ApJ, 2004, 612, 1206-1213) with the spectrum obtained by analyzing computer simulation results of the distribution of dust particles which migrated from different sources (Ipatov et al., Annals of New York Academy of Sciences, 2004, v. 1017, 66-80). Now we compare the rotation curves, i.e., plots of velocities of Mg I line (at zero inclination) versus elongations ǎrepsilon (measured eastward from the Sun). The comparison of the observed rotation curves with the models for dust particles of different sizes (hence for different values of the ratio between the radiation pressure force and gravitational force β ) started from asteroids, comets (2P/Encke, 10P/Tempel 2, 39P/Oterma), and trans-Neptunian objects allowed to make some conclusions about sources of zodiacal dust particles. The rotation curves obtained for different scattering functions were similar for 30<ǎrepsilon<330 deg. For asteroidal dust particles and particles originating from comets 39P and 10P, rotation curves are relatively close to each other at β <0.2. For 2P particles the difference between the rotation curves obtained at different β was considerable in case of the particles produced at aphelion. For asteroidal dust particles modeled rotation curves differed from the observed ones, and for ǎrepsilon<240o modeled velocities were smaller by several km/s; for 10P and 39P particles they were smaller than those for observations at ǎrepsilon<160o and 60<ǎrepsilon<150o, respectively, but for 39P particles the difference was smaller than that for asteroidal and 10P particles. For trans-Neptunian particles the rotation curves were in agreement with the observations at ǎrepsilon<180o, but modeled velocities were smaller than observational velocities at 200<ǎrepsilon<250o. The rotation curves corresponding to particles originating

  12. Particles trajectories in magnetic filaments

    SciTech Connect

    Bret, A.

    2015-07-15

    The motion of a particle in a spatially harmonic magnetic field is a basic problem involved, for example, in the mechanism of formation of a collisionless shock. In such settings, it is generally reasoned that particles entering a Weibel generated turbulence are trapped inside it, provided their Larmor radius in the peak field is smaller than the field coherence length. The goal of this work is to put this heuristic conclusion on firm ground by studying, both analytically and numerically, such motion. A toy model is analyzed, consisting of a relativistic particle entering a region of space occupied by a spatially harmonic field. The particle penetrates the magnetic structure in a direction aligned with the magnetic filaments. Although the conclusions are not trivial, the main result is confirmed.

  13. Coaxial charged particle energy analyzer

    NASA Technical Reports Server (NTRS)

    Kelly, Michael A. (Inventor); Bryson, III, Charles E. (Inventor); Wu, Warren (Inventor)

    2011-01-01

    A non-dispersive electrostatic energy analyzer for electrons and other charged particles having a generally coaxial structure of a sequentially arranged sections of an electrostatic lens to focus the beam through an iris and preferably including an ellipsoidally shaped input grid for collimating a wide acceptance beam from a charged-particle source, an electrostatic high-pass filter including a planar exit grid, and an electrostatic low-pass filter. The low-pass filter is configured to reflect low-energy particles back towards a charged particle detector located within the low-pass filter. Each section comprises multiple tubular or conical electrodes arranged about the central axis. The voltages on the lens are scanned to place a selected energy band of the accepted beam at a selected energy at the iris. Voltages on the high-pass and low-pass filters remain substantially fixed during the scan.

  14. Lunar Regolith Particle Shape Analysis

    NASA Technical Reports Server (NTRS)

    Kiekhaefer, Rebecca; Hardy, Sandra; Rickman, Douglas; Edmunson, Jennifer

    2013-01-01

    Future engineering of structures and equipment on the lunar surface requires significant understanding of particle characteristics of the lunar regolith. Nearly all sediment characteristics are influenced by particle shape; therefore a method of quantifying particle shape is useful both in lunar and terrestrial applications. We have created a method to quantify particle shape, specifically for lunar regolith, using image processing. Photomicrographs of thin sections of lunar core material were obtained under reflected light. Three photomicrographs were analyzed using ImageJ and MATLAB. From the image analysis measurements for area, perimeter, Feret diameter, orthogonal Feret diameter, Heywood factor, aspect ratio, sieve diameter, and sieve number were recorded. Probability distribution functions were created from the measurements of Heywood factor and aspect ratio.

  15. Particle Acceleration in Cosmic Plasmas

    SciTech Connect

    Zank, G.P.; Gaisser, T.K. )

    1992-01-01

    This proceedings includes papers presented at the Bartol ResearchInstitute, on topics concerning particle acceleration in stellar, space andgalactic environments. Two of the papers from this proceedings have beenabstracted for the database. (AIP)

  16. Plasma forces on deposited particles

    NASA Astrophysics Data System (ADS)

    Heijmans, Lucas; Nijdam, Sander

    2016-09-01

    A plasma can have many effects on a substrate. In this contribution we focus on its effects on micrometer sized particles on the substrate. We are especially interested in forces acting on these particles. These have been suggested to be responsible for the lunar glow observed by the Apollo mission astronauts. They have recently also attracted interest as a possible cleaning mechanism for the high-tech industry. We will present experimental measurements of the forces acting on a particle on a substrate under influence of a plasma. To this extend we have developed two specialised experimental setups. They use extreme accelerations (up to one million times the earth gravitational acceleration) to balance forces on the particle. We will show quantitative measurements of the plasma force effects, and show what underlying physical effects cause them.

  17. Particle platforms for cancer immunotherapy

    PubMed Central

    Serda, Rita Elena

    2013-01-01

    Elevated understanding and respect for the relevance of the immune system in cancer development and therapy has led to increased development of immunotherapeutic regimens that target existing cancer cells and provide long-term immune surveillance and protection from cancer recurrence. This review discusses using particles as immune adjuvants to create vaccines and to augment the anticancer effects of conventional chemotherapeutics. Several particle prototypes are presented, including liposomes, polymer nanoparticles, and porous silicon microparticles, the latter existing as either single- or multiparticle platforms. The benefits of using particles include immune-cell targeting, codelivery of antigens and immunomodulatory agents, and sustained release of the therapeutic payload. Nanotherapeutic-based activation of the immune system is dependent on both intrinsic particle characteristics and on the immunomodulatory cargo, which may include danger signals known as pathogen-associated molecular patterns and cytokines for effector-cell activation. PMID:23761969

  18. Progress in smooth particle hydrodynamics

    SciTech Connect

    Wingate, C.A.; Dilts, G.A.; Mandell, D.A.; Crotzer, L.A.; Knapp, C.E.

    1998-07-01

    Smooth Particle Hydrodynamics (SPH) is a meshless, Lagrangian numerical method for hydrodynamics calculations where calculational elements are fuzzy particles which move according to the hydrodynamic equations of motion. Each particle carries local values of density, temperature, pressure and other hydrodynamic parameters. A major advantage of SPH is that it is meshless, thus large deformation calculations can be easily done with no connectivity complications. Interface positions are known and there are no problems with advecting quantities through a mesh that typical Eulerian codes have. These underlying SPH features make fracture physics easy and natural and in fact, much of the applications work revolves around simulating fracture. Debris particles from impacts can be easily transported across large voids with SPH. While SPH has considerable promise, there are some problems inherent in the technique that have so far limited its usefulness. The most serious problem is the well known instability in tension leading to particle clumping and numerical fracture. Another problem is that the SPH interpolation is only correct when particles are uniformly spaced a half particle apart leading to incorrect strain rates, accelerations and other quantities for general particle distributions. SPH calculations are also sensitive to particle locations. The standard artificial viscosity treatment in SPH leads to spurious viscosity in shear flows. This paper will demonstrate solutions for these problems that they and others have been developing. The most promising is to replace the SPH interpolant with the moving least squares (MLS) interpolant invented by Lancaster and Salkauskas in 1981. SPH and MLS are closely related with MLS being essentially SPH with corrected particle volumes. When formulated correctly, JLS is conservative, stable in both compression and tension, does not have the SPH boundary problems and is not sensitive to particle placement. The other approach to

  19. Microstructure of Purified Rubber Particles.

    PubMed

    Wood; Cornish

    2000-05-01

    Purified rubber particles from Hevea brasiliensis (Brazilian rubber tree), Parthenium argentatum (guayule), Ficus elastica (Indian rubber tree), and Euphorbia lactiflua were examined and compared using conventional scanning electron microscopy (SEM), field-emission SEM, cryo-SEM, and transmission electron microscopy (TEM). Rubber particles of all four species were spherical; they varied in size and had a uniform homogeneous material, the rubber core, surrounded by a contiguous monolayer (half-unit) membrane. Frozen-hydrated and/or untreated particles from H. brasiliensis and P. argentatum deformed and fused readily, whereas those from F. elastica and E. lactiflua retained their spherical shapes. These results indicate that the surface components of the H. brasiliensis and P. argentatum particles are more fluid than those of F. elastica or E. lactiflua. When fixed in aldehyde, F. elastica particles retained their spherical exterior shapes but had hollow centers, whereas H. brasiliensis and P. argentatum particles completely collapsed. In aldehyde-osmium tetroxide-fixed material, the rubber core of F. elastica was poorly preserved in some particles in which only a small amount of the rubber core remained adhering to the monolayer membrane, leaving a hollow center. Euphorbia lactiflua particles were well preserved in terms of retaining the rubber core; however, the membrane was not as easily discernible as it was in the other three species. Both H. brasiliensis and P. argentatum were well preserved following fixation; their cores remained filled with rubber, and their monolayer membranes were defined. The addition of potassium permanganate to the fixation-staining regime resulted in higher-contrast micrographs and more well defined monolayer membranes.

  20. Dye Sensitization of Semiconductor Particles

    SciTech Connect

    Hartland, G. V.

    2003-01-13

    In this project electron transfer at semiconductor liquid interfaces was examined by ultrafast time-resolved and steady-state optical techniques. The experiments primarily yielded information about the electron transfer from titanium dioxide semiconductor particles to absorbed molecules. The results show that the rate of electron transfer depends on the structure of the molecule, and the crystalline phase of the particle. These results can be qualitatively explained by Marcus theory for electron transfer.

  1. Long range alpha particle detector

    DOEpatents

    MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

    1993-02-02

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  2. Hybrid particles and associated methods

    DOEpatents

    Fox, Robert V; Rodriguez, Rene; Pak, Joshua J; Sun, Chivin

    2015-02-10

    Hybrid particles that comprise a coating surrounding a chalcopyrite material, the coating comprising a metal, a semiconductive material, or a polymer; a core comprising a chalcopyrite material and a shell comprising a functionalized chalcopyrite material, the shell enveloping the core; or a reaction product of a chalcopyrite material and at least one of a reagent, heat, and radiation. Methods of forming the hybrid particles are also disclosed.

  3. Particle creation in bouncing cosmologies

    NASA Astrophysics Data System (ADS)

    Celani, Diogo C. F.; Pinto-Neto, Nelson; Vitenti, Sandro D. P.

    2017-01-01

    We investigate scalar particle creation in a set of bouncing models where the bounce occurs due to quantum cosmological effects described by the Wheeler-DeWitt equation. The scalar field can be either conformally or minimally coupled to gravity, and it can be massive or massless, without self-interaction. The analysis is made for models containing a single radiation fluid and for the more realistic case of models containing the usual observed radiation and dust fluids, which can fit most of the observed features of our universe, including an almost scale invariant power spectrum of scalar cosmological perturbations. In the conformal coupling case, the particle production is negligible. In the minimal coupling case, for massive particles, the results point to the same physical conclusion within observational constraints: particle production is most important at the bounce energy scale, and it is not sensitive either to its mass or to whether there is dust in the background model. The only caveat is the case where the particle mass is larger than the bounce energy scale. On the other hand, the energy density of produced massive particles depend on their masses and the energy scale of the bounce. For very large masses and deep bounces, this energy density may overcome that of the background. In the case of massless particles, the energy density of produced particles can become comparable to the background energy density only for bounces occurring at energy scales comparable to the Planck scale or above, which lies beyond the scope of this paper: we expect that the simple Wheeler-DeWitt approach we are using should be valid only at scales a few orders of magnitude below the Planck energy. Nevertheless, in the case in which dust is present, there is an infrared divergence, which becomes important only for scales much larger than today's Hubble radius.

  4. New particle searches at PEP

    SciTech Connect

    Berley, D.; Bulos, F.; Cheng, D.; Cork, B.; Limon, P.; Litke, A.; Nauenberg, U.; Rosen, J.; Shen, B.; Sulak, L.

    1988-01-01

    The new particles that could be produced at PEP are discussed in terms of their specific signatures and production rates. We find that a small number of general signatures characterize these particles. Backgrounds associated with the general signatures are considered and necessary rejection rates are calculated. We describe several typical detectors and tabulate the requirements they place on the PEP machine and the experimental areas. 10 figs., 2 tabs.

  5. Microelectrophoresis of selected mineral particles

    NASA Technical Reports Server (NTRS)

    Herren, B. J.; Tipps, R. W.; Alexander, K. D.

    1982-01-01

    Particle mobilities of ilmenite, labradorite plagioclase, enstatite pyroxene, and olivine were measured with a Rank microelectrophoresis system to evaluate indicated mineral separability. Sodium bicarbonate buffer suspension media with and without additives (0.0001 M DTAB and 5 percent v/v ethylene glycol) were used to determine differential adsorption by mineral particles and modification of relative mobilities. Good separability between some minerals was indicated; additives did not enhance separability.

  6. Particle-laden tubeless siphon

    NASA Astrophysics Data System (ADS)

    Joseph, Daniel; Wang, Jing

    2003-11-01

    A tubeless siphon was created by sucking a 1% aqueous Polyox(Polyox is a registered trademark of Union Carbide.) solution laden with particles from a beaker into a cylinder by a moving piston. The piston speed and particle concentration were varied. At very high rates of withdrawal, all the fluid could be removed before the siphon broke. In this case, the beaker was completely cleaned without a trace of liquid. The addition of small concentrations of small, nearly neutrally buoyant particles greatly enhanced the pulling power of the liquid, reducing the threshold speed of withdrawal at which the beaker was completely cleaned. At speeds of withdrawal smaller than the threshold not all of the fluid-particle mixture is pulled out of the beaker. The amount pulled out first increases, then decreases as the particle concentration is increased. We present an argument, based on viscoelastic potential flow, that the enhancement of the effective extensional stress is due to the reversal of the sign of the normal stresses at stagnation points on the particles.

  7. Microscope Image of Scavenged Particles

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image from NASA's Phoenix Mars Lander's Optical Microscope shows a strongly magnetic surface which has scavenged particles from within the microscope enclosure before a sample delivery from the lander's Robotic Arm. The particles correspond to the larger grains seen in fine orange material that makes up most of the soil at the Phoenix site. They vary in color, but are of similar size, about one-tenth of a millimeter.

    As the microscope's sample wheel moved during operation, these particles also shifted, clearing a thin layer of the finer orange particles that have also been collected. Together with the previous image, this shows that the larger grains are much more magnetic than the fine orange particles with a much larger volume of the grains being collected by the magnet. The image is 2 milimeters across.

    It is speculated that the orange material particles are a weathering product from the larger grains, with the weathering process both causing a color change and a loss of magnetism.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  8. Particle hydrodynamics with tessellation techniques

    NASA Astrophysics Data System (ADS)

    Heß, Steffen; Springel, Volker

    2010-08-01

    Lagrangian smoothed particle hydrodynamics (SPH) is a well-established approach to model fluids in astrophysical problems, thanks to its geometric flexibility and ability to automatically adjust the spatial resolution to the clumping of matter. However, a number of recent studies have emphasized inaccuracies of SPH in the treatment of fluid instabilities. The origin of these numerical problems can be traced back to spurious surface effects across contact discontinuities, and to SPH's inherent prevention of mixing at the particle level. We here investigate a new fluid particle model where the density estimate is carried out with the help of an auxiliary mesh constructed as the Voronoi tessellation of the simulation particles instead of an adaptive smoothing kernel. This Voronoi-based approach improves the ability of the scheme to represent sharp contact discontinuities. We show that this eliminates spurious surface tension effects present in SPH and that play a role in suppressing certain fluid instabilities. We find that the new `Voronoi Particle Hydrodynamics' (VPH) described here produces comparable results to SPH in shocks, and better ones in turbulent regimes of pure hydrodynamical simulations. We also discuss formulations of the artificial viscosity needed in this scheme and how judiciously chosen correction forces can be derived in order to maintain a high degree of particle order and hence a regular Voronoi mesh. This is especially helpful in simulating self-gravitating fluids with existing gravity solvers used for N-body simulations.

  9. Measuring momentum for charged particle tomography

    DOEpatents

    Morris, Christopher; Fraser, Andrew Mcleod; Schultz, Larry Joe; Borozdin, Konstantin N.; Klimenko, Alexei Vasilievich; Sossong, Michael James; Blanpied, Gary

    2010-11-23

    Methods, apparatus and systems for detecting charged particles and obtaining tomography of a volume by measuring charged particles including measuring the momentum of a charged particle passing through a charged particle detector. Sets of position sensitive detectors measure scattering of the charged particle. The position sensitive detectors having sufficient mass to cause the charged particle passing through the position sensitive detectors to scatter in the position sensitive detectors. A controller can be adapted and arranged to receive scattering measurements of the charged particle from the charged particle detector, determine at least one trajectory of the charged particle from the measured scattering; and determine at least one momentum measurement of the charged particle from the at least one trajectory. The charged particle can be a cosmic ray-produced charged particle, such as a cosmic ray-produced muon. The position sensitive detectors can be drift cells, such as gas-filled drift tubes.

  10. Particle analysis in an acoustic cytometer

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D

    2012-09-18

    The present invention is a method and apparatus for acoustically manipulating one or more particles. Acoustically manipulated particles may be separated by size. The particles may be flowed in a flow stream and acoustic radiation pressure, which may be radial, may be applied to the flow stream. This application of acoustic radiation pressure may separate the particles. In one embodiment, the particles may be separated by size, and as a further example, the larger particles may be transported to a central axis.

  11. Particle-in-Cell simulation of energetic particles driven instabilities

    NASA Astrophysics Data System (ADS)

    Chen, Yang; Parker, Scott E.; Lang, Jianying; Fu, Guoyong

    2009-11-01

    We present simulations of the evolution of energetic particles driven modes with the gyrokinetic turbulence code GEMfootnotetextY. Chen and S. E. Parker, J. Comp. Phys. 220, 839 (2007), except that kinetic electrons are replaced by a mass-less fluid model. PIC simulations of energetic particles use either the conventional full-f method or the δ method. The latter is adequate for low-amplitude fluctuation amplitudes. The collisional δ -methodfootnotetextY. Chen and R. White, Phys. Plasmas 4, 3591 (1997) is used to systematically account for collisions and particle source and sink. Steady state saturation amplitudes are benchmarked with predictions of analytic theory. We also employ full-f simulationsfootnotetextY. Todo et. al, Phys. Plasmas 10, 2888 (2003) to study bursty events in which the instabilities reach large amplitudes and cause macroscopic redistribution or loss of the particles. With full-f it is easy to retain all the nonlinear effects and treat accurately discontinuities in the distribution function at phase-space boundaries. Whereas the energetic particle current is neglegible in the Ampere's law in δ simulations, it is important in full-f simulations. Thermal ion kinetic effects are observed to be important.

  12. Particle transport in 3 He-rich events: wave-particle interactions and particle anisotropy measurements

    NASA Astrophysics Data System (ADS)

    Tsurutani, B. T.; Zhang, L. D.; Mason, G. L.; Lakhina, G. S.; Hada, T.; Arballo, J. K.; Zwickl, R. D.

    2002-04-01

    Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths l

  13. Micromechanical Origin of Particle Size Segregation

    NASA Astrophysics Data System (ADS)

    Jing, L.; Kwok, C. Y.; Leung, Y. F.

    2017-03-01

    We computationally study the micromechanics of shear-induced size segregation and propose distinct migration mechanisms for individual large and small particles. While small particles percolate through voids without enduring contacts, large particles climb under shear through their crowded neighborhoods with anisotropic contact network. Particle rotation associated with shear is necessary for the upward migration of large particles. Segregation of large particles can be suppressed with inadequate friction, or with no rotation; increasing interparticle friction promotes the migration of large particles, but has little effect on the percolation of small particles.

  14. Lattice-Boltzmann simulations of repulsive particle-particle and particle-wall interactions: Coughing and choking

    NASA Astrophysics Data System (ADS)

    Başaǧaoǧlu, Hakan; Succi, Sauro

    2010-04-01

    We propose and numerically investigate a new particle retention mechanism for particle entrapment in creeping flows in a constricted section of a saturated rough-walled narrow flow channel. We hypothesize that particles, whose size is smaller than channel width, can be temporarily or permanently immobilized in a flow channel away from channel walls due to particle-particle and particle-wall repulsive potentials, and, consequently, the flow field is clogged temporarily (coughing) or permanently (choking). Two mathematically simplified repulsive particle-particle and particle-wall interaction potentials are incorporated into a two-dimensional colloidal lattice-Boltzmann model. These potentials are two-body Lennard-Jones 12 and screened electrostatic repulsive potentials. Numerical simulations reveal that unlike in smooth-walled flow channels, particles are entrapped away from rough-walled channel walls and subsequently clog the flow field if fluid-drag and repulsive forces on particles are in balance. Off-balance forces, however, could result in temporary clogging if repulsive forces are stronger on the advancing edge of a particle than on its trailing edge. The new conceptualization and two-particle numerical simulations successfully captured (i) temporary entrapment of two particles (coughing), (ii) temporary entrapment of one of the particles with permanent entrapment of the other particle (coughing-choking), and (iii) permanent entrapment of both particles (choking) as a function of repulsive interaction strength.

  15. Electrostatic particle collection in vacuum

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  16. Dissipative particle dynamics with attractive and repulsive particle-particle interactions

    SciTech Connect

    Paul Meakin; Moubin Liu; Hai Huang

    2006-01-01

    In molecular dynamics simulations, a combination of short-range repulsive and long-range attractive interactions allows the behavior of gases, liquids, solids, and multiphase systems to be simulated. We demonstrate that dissipative particle dynamics (DPD) simulations with similar pairwise particle-particle interactions can also be used to simulate the dynamics of multiphase fluids. In these simulations, the positive, short-range, repulsive part of the interaction potentials were represented by polynomial spline functions such as those used as smoothing functions in smoothed particle hydrodynamics, and the negative long-range part of the interaction has the same form but a different range and amplitude. If a single spline function corresponding to a purely repulsive interaction is used, the DPD fluid is a gas, and we show that the Poiseuille flow of this gas can be described accurately by the Navier-Stokes equation at low Reynolds numbers. In a two-component system in which the purely repulsive interactions between different components are substantially larger than the purely repulsive intracomponent interactions, separation into two gas phases occurs, in agreement with results obtained using DPD simulations with standard repulsive particle-particle interactions. Finally, we show that a combination of short-range repulsive interactions and long-range attractive interactions can be used to simulate the behavior of liquid drops surrounded by a gas. Similar models can be used to simulate a wide range of processes such as multiphase fluid flow through fractures and porous media with complex geometries and wetting behaviors.

  17. Laser and Particle Guiding Micro-Elements for Particle Accelerators

    SciTech Connect

    Plettner, T.; Gaume, R.; Wisdom, J.; Spencer, J.; /SLAC

    2005-06-07

    Laser driven particle accelerators require sub-micron control of the laser field as well as precise electron-beam guiding so fabrication techniques that allow integrating both elements into an accelerator-on-chip format become critical for the success of such next generation machines. Micromachining technology for silicon has been shown to be one such feasible technology in PAC2003[1] but with a variety of complications on the laser side. However, fabrication of transparent ceramics has become an interesting technology that could be applied for laser-particle accelerators in several ways. We discuss the advantages such as the range of materials available and ways to implement them followed by some different test examples we been considered. One important goal is an integrated system that avoids having to inject either laser or particle pulses into these structures.

  18. Particle Image Velocimetry Applications Using Fluorescent Dye-Doped Particles

    NASA Technical Reports Server (NTRS)

    Petrosky, Brian J.; Maisto, Pietro; Lowe, K. Todd; Andre, Matthieu A.; Bardet, Philippe M.; Tiemsin, Patsy I.; Wohl, Christopher J.; Danehy, Paul M.

    2015-01-01

    Polystyrene latex sphere particles are widely used to seed flows for velocimetry techniques such as Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV). These particles may be doped with fluorescent dyes such that signals spectrally shifted from the incident laser wavelength may be detected via Laser Induced Fluorescence (LIF). An attractive application of the LIF signal is achieving velocimetry in the presence of strong interference from laser scatter, opening up new research possibilities very near solid surfaces or at liquid/gas interfaces. Additionally, LIF signals can be used to tag different fluid streams to study mixing. While fluorescence-based PIV has been performed by many researchers for particles dispersed in water flows, the current work is among the first in applying the technique to micron-scale particles dispersed in a gas. A key requirement for such an application is addressing potential health hazards from fluorescent dyes; successful doping of Kiton Red 620 (KR620) has enabled the use of this relatively safe dye for fluorescence PIV for the first time. In this paper, basic applications proving the concept of PIV using the LIF signal from KR620-doped particles are exhibited for a free jet and a twophase flow apparatus. Results indicate that while the fluorescence PIV techniques are roughly 2 orders of magnitude weaker than Mie scattering, they provide a viable method for obtaining data in flow regions previously inaccessible via standard PIV. These techniques have the potential to also complement Mie scattering signals, for example in multi-stream and/or multi-phase experiments.

  19. Virtual Energetic Particle Observatory (VEPO)

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Lal, Nand; McGuire, Robert E.; Szabo, Adam; Narock, Thomas W.; Armstrong, Thomas P.; Manweiler, Jerry W.; Patterson, J. Douglas; Hill, Matthew E.; Vandergriff, Jon D.; McKibben, Robert B.; Lopate, Clifford; Tranquille, Cecil

    2008-01-01

    The Virtual Energetic Particle Observatory (VEPO) focuses on improved discovery, access, and usability of heliospheric energetic particle and ancillary data products from selected spacecraft and sub-orbital instruments of the heliophysics data environment. The energy range of interest extends over the full range of particle acceleration from keV energies of suprathermal seed particles to GeV energies of galactic cosmic ray particles. Present spatial coverage is for operational and legacy spacecraft operating from the inner to the outer heliosphere, e.g. from measurements by the two Helios spacecraft to 0.3 AU to the inner heliosheath region now being traversed by the two Voyager spacecraft. This coverage will eventually be extended inward to ten solar radii by the planned NASA solar probe mission and at the same time beyond the heliopause into the outer heliosheath by continued Voyager operations. The geospace fleet of spacecraft providing near-Earth interplanetary measurements, selected magnetospheric spacecraft providing direct measurements of penetrating interplanetary energetic particles, and interplanetary cruise measurements from planetary spacecraft missions further extend VEPO resources to the domain of geospace and planetary interactions. Ground-based (e.g., neutron monitor) and high-altitude suborbital measurements can expand coverage to the highest energies of galactic cosmic rays affected by heliospheric interaction and of solar energetic particles. Science applications include investigation of solar flare and coronal mass ejection events. acceleration and transport of interplanetary particles within the inner heliosphere, cosmic ray interactions with planetary surfaces and atmospheres, sources of suprathermal and anomalous cosmic ray ions in the outer heliosphere, and solar cycle modulation of galactic cosmic rays. Robotic and human exploration, and eventual habitation, of planetary and space environments beyond the Earth require knowledge of radiation

  20. Solar Energetic Particle Spectrometer (SEPS)

    NASA Technical Reports Server (NTRS)

    Christl, Mark J.

    2009-01-01

    An outstanding problem of solar and heliospheric physics is the transport of solar energetic particles. The more energetic particles arriving early in the event can be used to probe the transport processes. The arrival direction distribution of these particles carries information about scattering during their propagation to Earth that can be used to test models of interplanetary transport. Also, of considerable importance to crewed space missions is the level of ionizing radiation in the interplanetary medium, and the dose that the crew experiences during an intense solar particle event, as well as the risk to space systems. A recent study concludes that 90% of the absorbed dose results from particles in the energy range 20-550 MeV. We will describe a new compact instrument concept, SEPS, that can cover the energy range from 50-600 MeV with a single compact detector. This energy range has been difficult to cover. There are only limited data, generally available only in broad energy bins, from a few past and present instruments outside Earth s magnetosphere. The SEPS concept can provide improved measurements for this energy range and its simple light-weight design could be easily accommodated on future missions.

  1. Health benefits of particle filtration.

    PubMed

    Fisk, W J

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, for example, 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  2. Health Benefits of Particle Filtration

    SciTech Connect

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  3. Health Benefits of Particle Filtration

    SciTech Connect

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  4. Particle fallout/activity sensor

    NASA Technical Reports Server (NTRS)

    Curtis, Ihlefeld M. (Inventor); Youngquist, Robert C. (Inventor); Moerk, John S. (Inventor); Rose, Kenneth A., III (Inventor)

    1995-01-01

    A particle fallout/activity sensor measures relative amounts of dust or other particles which collect on a mirror in an area to be monitored. The sensor includes a sensor module and a data acquisition module, both of which can be operated independently of one another or in combination with one another. The sensor module includes a housing containing the mirror, an LED assembly for illuminating the mirror and an optical detector assembly for detecting light scattered off of the mirror by dust or other particles collected thereon. A microprocessor controls operation of the sensor module's components and displays results of a measurement on an LCD display mounted on the housing. A push button switch is also mounted on the housing which permits manual initiation of a measurement. The housing is constructed of light absorbing material, such as black delrin, which minimizes detection of light by the optical detector assembly other than that scattered by dust or particles on the mirror. The data acquisition module can be connected to the sensor module and includes its own microprocessor, a timekeeper and other digital circuitry for causing the sensor module to make a measurement periodically and send the measurement data to the data acquisition module for display and storage in memory for later retrieval and transfer to a separate computer. The time tagged measurement data can also be used to determine the relative level of activity in the monitored area since this level is directly related to the amount of dust or particle fallout in the area.

  5. Diffusion of active chiral particles

    NASA Astrophysics Data System (ADS)

    Sevilla, Francisco J.

    2016-12-01

    The diffusion of chiral active Brownian particles in three-dimensional space is studied analytically, by consideration of the corresponding Fokker-Planck equation for the probability density of finding a particle at position x and moving along the direction v ̂ at time t , and numerically, by the use of Langevin dynamics simulations. The analysis is focused on the marginal probability density of finding a particle at a given location and at a given time (independently of its direction of motion), which is found from an infinite hierarchy of differential-recurrence relations for the coefficients that appear in the multipole expansion of the probability distribution, which contains the whole kinematic information. This approach allows the explicit calculation of the time dependence of the mean-squared displacement and the time dependence of the kurtosis of the marginal probability distribution, quantities from which the effective diffusion coefficient and the "shape" of the positions distribution are examined. Oscillations between two characteristic values were found in the time evolution of the kurtosis, namely, between the value that corresponds to a Gaussian and the one that corresponds to a distribution of spherical shell shape. In the case of an ensemble of particles, each one rotating around a uniformly distributed random axis, evidence is found of the so-called effect "anomalous, yet Brownian, diffusion," for which particles follow a non-Gaussian distribution for the positions yet the mean-squared displacement is a linear function of time.

  6. Engineered plant biomass feedstock particles

    DOEpatents

    Dooley, James H.; Lanning, David N.; Broderick, Thomas F.

    2011-10-18

    A novel class of flowable biomass feedstock particles with unusually large surface areas that can be manufactured in remarkably uniform sizes using low-energy comminution techniques. The feedstock particles are roughly parallelepiped in shape and characterized by a length dimension (L) aligned substantially with the grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. The particles exhibit a disrupted grain structure with prominent end and surface checks that greatly enhances their skeletal surface area as compared to their envelope surface area. The L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers. The W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers. The L.times.W dimensions define a pair of substantially parallel top surfaces characterized by some surface checking between longitudinally arrayed fibers. At least 80% of the particles pass through a 1/4 inch screen having a 6.3 mm nominal sieve opening but are retained by a No. 10 screen having a 2 mm nominal sieve opening. The feedstock particles are manufactured from a variety of plant biomass materials including wood, crop residues, plantation grasses, hemp, bagasse, and bamboo.

  7. Particle cosmology comes of age

    SciTech Connect

    Turner, M.S.

    1987-12-01

    The application of modern ideas in particle physics to astrophysical and cosmological settings is a continuation of a fruitful tradition in astrophysics which began with the application of atomic physics, and then nuclear physics. In the past decade particle cosmology and particle astrophysics have been recognized as 'legitimate activities' by both particle physicists and astrophysicists and astronomers. During this time there has been a high level of theoretical activity producing much speculation about the earliest history of the Universe, as well as important and interesting astrophysical and cosmological constraints to particle physics theories. This period of intense theoretical activity has produced a number of ideas most worthy of careful consideration and scrutiny, and even more importantly, amenable to experimental/observational test. Among the ideas which are likely to be tested in the next decade are: the cosmological bound to the number of neutrino flavors, inflation, relic WIMPs as the dark matter, and MSW neutrino oscillations as a solution to the solar neutrino problems. 94 refs.

  8. Particle injector for fluid systems

    DOEpatents

    Ruch, Jeffrey F.

    1997-01-01

    A particle injector device provides injection of particles into a liquid eam. The device includes a funnel portion comprising a conical member having side walls tapering from a top opening (which receives the particles) down to a relatively smaller exit opening. A funnel inlet receives a portion of the liquid stream and the latter is directed onto the side walls of the conical member so as to create a cushion of liquid against which the particles impact. A main section of the device includes an inlet port in communication with the exit opening of the funnel portion. A main liquid inlet receives the main portion of the liquid stream at high pressure and low velocity and a throat region located downstream of the main liquid inlet accelerates liquid received by this inlet from the low velocity to a higher velocity so as to create a low pressure area at the exit opening of the funnel portion. An outlet opening of the main section enables the particles and liquid stream to exit from the injector device.

  9. Nanophotonics of isolated spherical particles

    NASA Astrophysics Data System (ADS)

    Geints, Yu. É.; Zemlyanov, A. A.; Panina, E. K.

    2010-09-01

    The problem of extreme focusing of an optical beam into the spatial region with wavelength dimensions is considered with the use of the special features of radiation interaction with isolated spherical particles. Results of numerical computations of the optical field intensity at the surface of silver particles of different radii upon exposure to laser radiation with different wavelengths are presented. It is demonstrated that the relative intensity of the plasmon optical field on the nanoparticle surface increases and the field focusing region decreases with increasing particle radius. Results of numerical computations illustrating the influence of the shell of composite nanoparticles comprising a dielectric core and a metal shell on the optical field intensity in the vicinity of the particle are presented. The problem of local optical foci of a transparent microparticle (photonic nanojets) is investigated. It is established that variation of the micron particle size, its optical properties, and laser radiation parameters allows the amplitude and spatial characteristics of the photonic nanojet region to be controlled efficiently.

  10. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  11. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  12. Particle Breakage in Agitated Dryers

    NASA Astrophysics Data System (ADS)

    Hare, Colin L.; Ghadiri, Mojtaba; Dennehy, Robert; Collier, Alan

    2009-06-01

    A method for predicting particle breakage in agitated dryers is described. The method utilizes an estimation of stresses and strains occurring in a dryer bed sheared by an impeller using the Distinct Element Method (DEM). An assemblage of particles is then subjected to these stresses in a shear cell to assess the extent of attrition under a range of stresses and strains. Paracetamol particles in the size range 500-600 μm are used for the experimental work. The relationship of attrition with stress and strain is then incorporated into the distribution of stress and strain in the dryer estimated by DEM. The extent of attrition for a range of conditions including the impeller speed has been analysed. The prediction shows impeller speed to have limited effect on attrition within the range of speeds tested.

  13. Quantum Particles From Quantum Information

    NASA Astrophysics Data System (ADS)

    Görnitz, T.; Schomäcker, U.

    2012-08-01

    Many problems in modern physics demonstrate that for a fundamental entity a more general conception than quantum particles or quantum fields are necessary. These concepts cannot explain the phenomena of dark energy or the mind-body-interaction. Instead of any kind of "small elementary building bricks", the Protyposis, an abstract and absolute quantum information, free of special denotation and open for some purport, gives the solution in the search for a fundamental substance. However, as long as at least relativistic particles are not constructed from the Protyposis, such an idea would remain in the range of natural philosophy. Therefore, the construction of relativistic particles without and with rest mass from quantum information is shown.

  14. Magnetotail particle dynamics and transport

    NASA Technical Reports Server (NTRS)

    Speiser, Theodore W.

    1995-01-01

    The main thrust of our research is to study the consequences of particle dynamics in the current sheet region of the magnetotail. The importance of understanding particle dynamics, in and near current sheets, cannot be over estimated, especially in light of NASA's recent interest in developing global circulation models to predict space weather. We have embarked on a long-term study to investigate the electrical resistance due to chaotic behavior, compare this resistance to inertial effects, and relate it to that resistance required in MHD modeling for reconnection to proceed. Using a single-particle model and observations, we have also found that a neutral line region can be remotely sensed. We plan to evaluate other cases of satellite observations near times of substorm onset to elucidate the relationship between the temporal development of a near-Earth neutral line and onset.

  15. Dispersion relations for unphysical particles

    NASA Astrophysics Data System (ADS)

    Siringo, Fabio

    2017-03-01

    Generalized dispersion relations are discussed for unphysical particles, e.g. confined degrees of freedom that are not present in the physical spectra but can give rise to observable bound states. While in general the propagator of the unphysical particles can have complex poles and cannot be reconstructed from the knowledge of the imaginary part, under reasonable assumptions the missing piece of information is shown to be in the rational function that contains the poles and must be added to the integral representation. For pure Yang-Mills theory, the rational part and the spectral term are identified in the explicit analytical expressions provided by the massive expansion of the gluon propagator. The multi particle spectral term turns out to be very small and the simple rational part provides, from first principles, an approximate propagator that is equivalent to the tree-level result of simple phenomenological models like the refined Gribov-Zwanziger model.

  16. Electrodynamics of massless charged particles

    SciTech Connect

    Lechner, Kurt

    2015-02-15

    We derive the classical dynamics of massless charged particles in a rigorous way from first principles. Since due to ultraviolet divergences this dynamics does not follow from an action principle, we rely on (a) Maxwell’s equations, (b) Lorentz- and reparameterization-invariance, and (c) local conservation of energy and momentum. Despite the presence of pronounced singularities of the electromagnetic field along Dirac-like strings, we give a constructive proof of the existence of a unique distribution-valued energy-momentum tensor. Its conservation requires the particles to obey standard Lorentz equations and they experience, hence, no radiation reaction. Correspondingly, the dynamics of interacting classical massless charged particles can be consistently defined, although they do not emit bremsstrahlung end experience no self-interaction.

  17. Naked singularities as particle accelerators

    SciTech Connect

    Patil, Mandar; Joshi, Pankaj S.

    2010-11-15

    We investigate here the particle acceleration by naked singularities to arbitrarily high center of mass energies. Recently it has been suggested that black holes could be used as particle accelerators to probe the Planck scale physics. We show that the naked singularities serve the same purpose and probably would do better than their black hole counterparts. We focus on the scenario of a self-similar gravitational collapse starting from a regular initial data, leading to the formation of a globally naked singularity. It is seen that when particles moving along timelike geodesics interact and collide near the Cauchy horizon, the energy of collision in the center of mass frame will be arbitrarily high, thus offering a window to Planck scale physics.

  18. CFD Modeling of Particle Resuspension

    NASA Astrophysics Data System (ADS)

    Degraw, Jason; Cimbala, John; Freihaut, James

    2006-11-01

    The phenomenon of resuspension plays a role in everyday life and is an important factor in indoor air quality. There are several models available for particle detachment, but the mechanisms by which particles are induced to lift off of a surface are not well explained in the literature. The lifting forces on a particle are generally too small to resuspend it, especially in the air flows generated by human activity (e.g., walking). We model the interaction of the aerodynamic disturbances and a thin layer of particles deposited on the surface. A standard CFD solver is used to compute the flow, and the particle transport model is one-way-coupled with the flow solution. Several time-dependent flows are considered, including an idealized footstep. The foot is represented using an immersed boundary technique, and is modeled as a disk that moves up and down with a trajectory patterned after experimental gait data. A jet and a radially moving vortex are generated as the foot approaches the floor. The strength of the jet is determined by the details of the foot movement near the surface. If the foot is slowed as it nears the floor, we find maximum velocities around 3 m/s, while the maximum velocity is more than doubled by a sudden stop. We have also computed a ``vacuum cleaner'' case to model the airflow generated by cleaning activities. In either case, the wall shear along the floor and the near-wall flow structure are used to examine the resuspension of particles.

  19. An investigation of particles suspension using smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Pazouki, Arman; Negrut, Dan

    2013-11-01

    This contribution outlines a method for the direct numerical simulation of rigid body suspensions in a Lagrangian-Lagrangian framework using extended Smoothed Particle Hydrodynamics (XSPH) method. The dynamics of the arbitrarily shaped rigid bodies is fully resolved via Boundary Condition Enforcing (BCE) markers and updated according to the general Newton-Euler equations of motion. The simulation tool, refered to herien as Chrono::Fluid, relies on a parallel implementation that runs on Graphics Processing Unit (GPU) cards. The simulation results obtained for transient Poiseuille flow, migration of cylinder and sphere in Poiseuille flow, and distribution of particles at different cross sections of the laminar flow of dilute suspension were respectively within 0.1%, 1%, and 5% confidence interval of analytical and experimental results reported in the literature. It was shown that at low Reynolds number, Re = O(1), the radial migration (a) behaves non-monotonically as the particles relative distance (distance over diameter) increases from zero to two; and (b) decreases as the particle skewness and size increases. The scaling of Chrono::Fluid was demonstrated in conjunction with a suspension dynamics analysis in which the number of ellipsoids went up to 3e4. Financial support was provided in part by National Science Foundation grant NSF CMMI-084044.

  20. Particle bursts from thunderclouds: Natural particle accelerators above our heads

    SciTech Connect

    Chilingarian, Ashot; Hovsepyan, Gagik; Hovhannisyan, Armen

    2011-03-15

    Strong electrical fields inside thunderclouds give rise to fluxes of high-energy electrons and, consequently, gamma rays and neutrons. Gamma rays and electrons are currently detected by the facilities of low orbiting satellites and by networks of surface particle detectors. During intensive particle fluxes, coinciding with thunderstorms, series of particle bursts were detected by the particle detectors of Aragats Space Environmental Center at an altitude of 3250 m. We classify the thunderstorm ground enhancements in 2 categories, one lasting microseconds, and the other lasting tens of minutes. Both types of events can occur at the same time, coinciding with a large negative electric field between the cloud and the ground and negative intracloud lightning. Statistical analysis of the short thunderstorm ground enhancement bursts sample suggests the duration is less than 50 {mu}s and spatial extension is larger than 1000 m{sup 2}. We discuss the origin of thunderstorm ground enhancements and its connection to the terrestrial gamma flashes detected by orbiting gamma-ray observatories.

  1. New Particle Searches Haunted by Virtual Lightest Supersymmetric Particles

    NASA Astrophysics Data System (ADS)

    Datta, Amitava; Guchhait, Monoranjan; Mukhopadhyaya, Biswarup

    Relatively light sneutrinos which are experimentally allowed but not favored theoretically, may significantly affect the currently popular search strategies for supersymmetric particles by decaying predominantly into an invisible channel. In such cases the second lightest neutralino also becomes invisible. Consequences of such scenario in connection with the ongoing searches at the Tevatron and LEP-II are discussed.

  2. Particle bursts from thunderclouds: Natural particle accelerators above our heads

    NASA Astrophysics Data System (ADS)

    Chilingarian, Ashot; Hovsepyan, Gagik; Hovhannisyan, Armen

    2011-03-01

    Strong electrical fields inside thunderclouds give rise to fluxes of high-energy electrons and, consequently, gamma rays and neutrons. Gamma rays and electrons are currently detected by the facilities of low orbiting satellites and by networks of surface particle detectors. During intensive particle fluxes, coinciding with thunderstorms, series of particle bursts were detected by the particle detectors of Aragats Space Environmental Center at an altitude of 3250 m. We classify the thunderstorm ground enhancements in 2 categories, one lasting microseconds, and the other lasting tens of minutes. Both types of events can occur at the same time, coinciding with a large negative electric field between the cloud and the ground and negative intracloud lightning. Statistical analysis of the short thunderstorm ground enhancement bursts sample suggests the duration is less than 50μs and spatial extension is larger than 1000m2. We discuss the origin of thunderstorm ground enhancements and its connection to the terrestrial gamma flashes detected by orbiting gamma-ray observatories.

  3. Particle size effects in particle-particle triboelectric charging studied with an integrated fluidized bed and electrostatic separator system

    NASA Astrophysics Data System (ADS)

    Bilici, Mihai A.; Toth, Joseph R.; Sankaran, R. Mohan; Lacks, Daniel J.

    2014-10-01

    Fundamental studies of triboelectric charging of granular materials via particle-particle contact are challenging to control and interpret because of foreign material surfaces that are difficult to avoid during contacting and measurement. The measurement of particle charge itself can also induce charging, altering results. Here, we introduce a completely integrated fluidized bed and electrostatic separator system that charges particles solely by interparticle interactions and characterizes their charge on line. Particles are contacted in a free-surface fluidized bed (no reactor walls) with a well-controlled fountain-like flow to regulate particle-particle contact. The charged particles in the fountain are transferred by a pulsed jet of air to the top of a vertically-oriented electrostatic separator consisting of two electrodes at oppositely biased high voltage. The free-falling particles migrate towards the electrodes of opposite charge and are collected by an array of cups where their charge and size can be determined. We carried out experiments on a bidisperse size mixture of soda lime glass particles with systematically varying ratios of concentration. Results show that larger particles fall close to the negative electrode and smaller particles fall close to the positive electrode, consistent with theory and prior experiments that larger particles charge positively and smaller particles charge negatively. The segregation of particles by charge for one of the size components is strongest when its collisions are mostly with particles of the other size component; thus, small particles segregate most strongly to the negative sample when their concentration in the mixture is small (and analogous results occur for the large particles). Furthermore, we find additional size segregation due to granular flow, whereby the fountain becomes enriched in larger particles as the smaller particles are preferentially expelled from the fountain.

  4. Particle size effects in particle-particle triboelectric charging studied with an integrated fluidized bed and electrostatic separator system

    SciTech Connect

    Bilici, Mihai A.; Toth, Joseph R.; Sankaran, R. Mohan; Lacks, Daniel J.

    2014-10-15

    Fundamental studies of triboelectric charging of granular materials via particle-particle contact are challenging to control and interpret because of foreign material surfaces that are difficult to avoid during contacting and measurement. The measurement of particle charge itself can also induce charging, altering results. Here, we introduce a completely integrated fluidized bed and electrostatic separator system that charges particles solely by interparticle interactions and characterizes their charge on line. Particles are contacted in a free-surface fluidized bed (no reactor walls) with a well-controlled fountain-like flow to regulate particle-particle contact. The charged particles in the fountain are transferred by a pulsed jet of air to the top of a vertically-oriented electrostatic separator consisting of two electrodes at oppositely biased high voltage. The free-falling particles migrate towards the electrodes of opposite charge and are collected by an array of cups where their charge and size can be determined. We carried out experiments on a bidisperse size mixture of soda lime glass particles with systematically varying ratios of concentration. Results show that larger particles fall close to the negative electrode and smaller particles fall close to the positive electrode, consistent with theory and prior experiments that larger particles charge positively and smaller particles charge negatively. The segregation of particles by charge for one of the size components is strongest when its collisions are mostly with particles of the other size component; thus, small particles segregate most strongly to the negative sample when their concentration in the mixture is small (and analogous results occur for the large particles). Furthermore, we find additional size segregation due to granular flow, whereby the fountain becomes enriched in larger particles as the smaller particles are preferentially expelled from the fountain.

  5. Detecting weakly interacting massive particles.

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Gelmini, G. B.

    The growing synergy between astrophysics, particle physics, and low background experiments strengthens the possibility of detecting astrophysical non-baryonic matter. The idea of direct detection is that an incident, massive weakly interacting particle could collide with a nucleus and transfer an energy that could be measured. The present low levels of background achieved by the PNL/USC Ge detector represent a new technology which yields interesting bounds on Galactic cold dark matter and on light bosons emitted from the Sun. Further improvements require the development of cryogenic detectors. The authors analyse the practicality of such detectors, their optimalization and background suppression using the "annual modulation effect".

  6. AEROSOL PARTICLE COLLECTOR DESIGN STUDY

    SciTech Connect

    Lee, S; Richard Dimenna, R

    2007-09-27

    A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

  7. Alpha-particle spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.

  8. The particles in town air

    PubMed Central

    Ellison, J. McK.

    1965-01-01

    Particles constitute an important part of air pollution, and their behaviour when suspended in air is very different from that of gas molecules: in particular, the mechanisms by which they become deposited on surfaces are different, and consequently the methods normally used for removing particles from the air, either for sampling or for cleaning it, rely mainly on mechanisms that do not enter into the behaviour of gas molecules. These mechanisms are described, and the ways in which they affect the problems of air pollution and its measurement are discussed. ImagesFIG. 8 PMID:14315713

  9. Solar Energetic Particle Spectral Breaks

    SciTech Connect

    Mewaldt, R.A.; Cohen, C.M.S.; Labrador, A.W.; Cummings, A.C.; Leske, R.A.; Stone, E.C.; Mason, G.M.; Desai, M.I.; Looper, M.L.; Mazur, J.E.; Haggerty, D.E.; Maclennan, C.G.; Li, G.; Wiedenbeck, M.E.

    2005-08-01

    The five large solar particle events during October-November 2003 presented an opportunity to test shock acceleration models with in-situ observations. We use solar particle spectra of H to Fe ions, measured by instruments on ACE, SAMPEX, and GOES-11, to investigate the Q/M-dependence of spectral breaks in the 28 October 2003 event. We find that the break energies scale as (Q/M)b with b {<=} 1.56 to 1.75, somewhat less than predicted. We also conclude that SEP spectra >100 MeV/nucleon are best fit by a double power-law shape.

  10. Active particles on curved surfaces

    NASA Astrophysics Data System (ADS)

    Fily, Yaouen; Baskaran, Aparna; Hagan, Michael

    Active systems have proved to be very sensitive to the geometry of their environment. This is often achieved by spending significant time at the boundary, probing its shape by gliding along it. I will discuss coarse graining the microscopic dynamics of self-propelled particles on a general curved surface to predict the way the density profile on the surface depends on its geometry. Beyond confined active particles, this formalism is a natural starting point to study objects that cannot leave the boundary at all, such as cells crawling on a curved substrate, animals running on uneven ground, or active colloids trapped at an interface.

  11. Charged particle mobility refrigerant analyzer

    DOEpatents

    Allman, S.L.; Chunghsuan Chen; Chen, F.C.

    1993-02-02

    A method for analyzing a gaseous electronegative species comprises the steps of providing an analysis chamber; providing an electric field of known potential within the analysis chamber; admitting into the analysis chamber a gaseous sample containing the gaseous electronegative species; providing a pulse of free electrons within the electric field so that the pulse of free electrons interacts with the gaseous electronegative species so that a swarm of electrically charged particles is produced within the electric field; and, measuring the mobility of the electrically charged particles within the electric field.

  12. Two particle distributions in jets

    SciTech Connect

    Willen, D.E.

    1980-01-01

    In this thesis, we study two particle spectra in the jets of hadrons which result when a parton is nearly blasted free from the force which confines it. After a few examples illustrating the use of the parton model in Quantum Chromodynamics, we discuss the leading logarithm analysis of the two particle fragmentation functions by Konishi, Ukawa and Veneziano (KUV). Handling the complications of resonance decay in the fashion of Field and Feynman, we proceed to apply the KUV method to two jet processes in e + e- annihilation and proton-proton collisions.

  13. Patchy Particle Model for Vitrimers

    NASA Astrophysics Data System (ADS)

    Smallenburg, Frank; Leibler, Ludwik; Sciortino, Francesco

    2013-11-01

    Vitrimers—a recently invented new class of polymers—consist of covalent networks that can rearrange their topology via a bond shuffling mechanism, preserving the total number of network links. We introduce a patchy particle model whose dynamics directly mimic the bond exchange mechanism and reproduce the observed glass-forming ability. We calculate the free energy of this model in the limit of strong (chemical) bonds between the particles, both via the Wertheim thermodynamic perturbation theory and using computer simulations. The system exhibits an entropy-driven phase separation between a network phase and a dilute cluster gas, bringing new insight into the swelling behavior of vitrimers in solvents.

  14. The Fermilab Particle Astrophysics Center

    SciTech Connect

    Not Available

    2004-11-01

    The Particle Astrophysics Center was established in fall of 2004. Fermilab director Michael S. Witherell has named Fermilab cosmologist Edward ''Rocky'' Kolb as its first director. The Center will function as an intellectual focus for particle astrophysics at Fermilab, bringing together the Theoretical and Experimental Astrophysics Groups. It also encompasses existing astrophysics projects, including the Sloan Digital Sky Survey, the Cryogenic Dark Matter Search, and the Pierre Auger Cosmic Ray Observatory, as well as proposed projects, including the SuperNova Acceleration Probe to study dark energy as part of the Joint Dark Energy Mission, and the ground-based Dark Energy Survey aimed at measuring the dark energy equation of state.

  15. Elementary Particles and Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.; Yang, C. N.

    1957-01-01

    Some general patterns of interactions between various elementary particles are reviewed and some general questions concerning the symmetry properties of these particles are studied. Topics are included on the theta-tau puzzle, experimental limits on the validity of parity conservation, some general discussions on the consequences due to possible non-invariance under P, C, and T, various possible experimental tests on invariance under P, C, and T, a two-component theory of the neutrino, a possible law of conservation of leptons and the universal Fermi interactions, and time reversal invariance and Mach's principle. (M.H.R.)

  16. Nuclear physics and particle therapy

    NASA Astrophysics Data System (ADS)

    Battistoni, G.

    2016-05-01

    The use of charged particles and nuclei in cancer therapy is one of the most successful cases of application of nuclear physics to medicine. The physical advantages in terms of precision and selectivity, combined with the biological properties of densely ionizing radiation, make charged particle approach an elective choice in a number of cases. Hadron therapy is in continuous development and nuclear physicists can give important contributions to this discipline. In this work some of the relevant aspects in nuclear physics will be reviewed, summarizing the most important directions of research and development.

  17. The Physical Principles of Particle Detectors.

    ERIC Educational Resources Information Center

    Jones, Goronwy Tudor

    1991-01-01

    Describes the use of a particle detector, an instrument that records the passage of particles through it, to determine the mass of a particle by measuring the particles momentum, speed, and kinetic energy. An appendix discusses the limits on the impact parameter. (MDH)

  18. Ultrafine Condensation Particle Counter Instrument Handbook

    SciTech Connect

    Kuang, C.

    2016-02-01

    The Model 3776 Ultrafine Condensation Particle Counter (UCPC; pictured in Appendix A) is designed for researchers interested in airborne particles smaller than 20 nm. With sensitivity to particles down to 2.5 nm in diameter, this UCPC is ideally suited for atmospheric and climate research, particle formation and growth studies, combustion and engine exhaust research, and nanotechnology research.

  19. Subdomain zinc ferrite particles: Synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Pannaparayil, T.; Komarneni, S.; Marande, R.; Zadarko, M.

    1990-05-01

    Ultrafine and nearly spherical particles of zinc ferrite were synthesized under mild hydrothermal conditions by precipitating from metal nitrates. These particles exhibited antiferromagnetic ordering below 13 K. Mössbauer spectroscopic measurements revealed the subdomain superparamagnetic nature of the particles having a narrow particle size distribution. The hydrothermal ferrite powders were found to sinter to almost theoretical density with little or no intragranular porosity.

  20. Particle-to-particle heterogeneous nature of coals. A case of large coal particles

    SciTech Connect

    Manovic, V.; Loncarevic, D.; Tokalic, R.

    2009-07-01

    In the present paper, the results of investigation of the heterogeneous nature of coals are given. Microscopic observations of coals of different rank and mineral matter content were performed. The content of minerals and macerals and the size of their grains were determined in the coal samples. Two samples of lignite rich in minerals were analyzed in detail by measuring the ash content for each particle and batches containing numerous (100) coal particles. The additional analyses were performed with the particles before and after sink-float separation. The obtained results showed an increase of heterogeneity with mineral matter content. The statistical analysis showed that many particles should be used for an experiment for obtaining reliable data with a desired level of certainty. In the case of batch experiments with 5 g Kolubara B coal (about 100 particles, size 4.76-7.0 mm), the experiment should be repeated at least 7, 19, and 100 times in order to obtain a mean value in the confidence intervals 5.0%, 2.5%, and 1.0%, respectively, for a 95% probability (if sample heterogeneity is the only cause for variations in results). However, regardless of increase of reproducibility and repeatability of obtained results, a large amount of samples and numerous repetitions of experiments cannot exclude differences in experimental results between homogenous and heterogeneous samples.

  1. Method of identifying defective particle coatings

    DOEpatents

    Cohen, Mark E.; Whiting, Carlton D.

    1986-01-01

    A method for identifying coated particles having defective coatings desig to retain therewithin a build-up of gaseous materials including: (a) Pulling a vacuum on the particles; (b) Backfilling the particles at atmospheric pressure with a liquid capable of wetting the exterior surface of the coated particles, said liquid being a compound which includes an element having an atomic number higher than the highest atomic number of any element in the composition which forms the exterior surface of the particle coating; (c) Drying the particles; and (d) Radiographing the particles. By television monitoring, examination of the radiographs is substantially enhanced.

  2. Gantry for medical particle therapy facility

    DOEpatents

    Trbojevic, Dejan [Wading River, NY

    2012-05-08

    A particle therapy gantry for delivering a particle beam to a patient includes a beam tube having a curvature defining a particle beam path and a plurality of fixed field magnets sequentially arranged along the beam tube for guiding the particle beam along the particle path. In a method for delivering a particle beam to a patient through a gantry, a particle beam is guided by a plurality of fixed field magnets sequentially arranged along a beam tube of the gantry and the beam is alternately focused and defocused with alternately arranged focusing and defocusing fixed field magnets.

  3. Gantry for medical particle therapy facility

    DOEpatents

    Trbojevic, Dejan

    2013-04-23

    A particle therapy gantry for delivering a particle beam to a patient includes a beam tube having a curvature defining a particle beam path and a plurality of superconducting, variable field magnets sequentially arranged along the beam tube for guiding the particle beam along the particle path. In a method for delivering a particle beam to a patient through a gantry, a particle beam is guided by a plurality of variable field magnets sequentially arranged along a beam tube of the gantry and the beam is alternately focused and defocused with alternately arranged focusing and defocusing variable field magnets.

  4. Particle astronomy and particle physics from the moon - The particle observatory

    NASA Technical Reports Server (NTRS)

    Wilson, Thomas L.

    1990-01-01

    Promising experiments from the moon using particle detectors are discussed, noting the advantage of the large flux collecting power Pc offered by the remote, stable environment of a lunar base. An observatory class of particle experiments is presented, based upon proposals at NASA's recent Stanford workshop. They vary from neutrino astronomy, particle astrophysics, and cosmic ray experiments to space physics and fundamental physics experiments such as proton decay and 'table-top' arrays. This research is background-limited on earth, and it is awkward and unrealistic in earth orbit, but is particularly suited for the moon where Pc can be quite large and the instrumentation is not subject to atmospheric erosion as it is (for large t) in low earth orbit.

  5. Producing Large-Particle Monodisperse Latexes

    NASA Technical Reports Server (NTRS)

    Vanderhoff, J. W.

    1986-01-01

    Chemical process produces latex particles of relatively large, uniform size for use as size standards for instrument calibration. Process, based on seeding of mixture by very small latex particles, yields particles measuring 2 to 30 micrometer or more in average size. Produces monodisperse latexes in which deviation from average size is less than 2 percent. Particles used directly, without tedious separation procedures for removing off-size particles.

  6. Particle size and particle-particle interactions on tensile properties and reinforcement of corn flour particles in natural rubber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Renewable corn flour has a significant reinforcement effect in natural rubber. The corn flour was hydrolyzed and microfluidized to reduce its particle size. Greater than 90% of the hydrolyzed corn flour had an average size of ~300 nm, a reduction of 33 times compared to unhydrolyzed corn flour. Comp...

  7. New particle observations in SELEX

    SciTech Connect

    Jun, Soon Yung; /Carnegie Mellon U.

    2004-12-01

    Particle observations in data from SELEX, the charm hadro-production experiment (E781) at Fermilab are reviewed. These include observations of the doubly charmed baryon {Xi}{sub cc}{sup +}(3520) and the charmed strange meson D{sub sJ}{sup +}(2632).

  8. Lithography using quantum entangled particles

    NASA Technical Reports Server (NTRS)

    Williams, Colin (Inventor); Dowling, Jonathan (Inventor); della Rossa, Giovanni (Inventor)

    2003-01-01

    A system of etching using quantum entangled particles to get shorter interference fringes. An interferometer is used to obtain an interference fringe. N entangled photons are input to the interferometer. This reduces the distance between interference fringes by n, where again n is the number of entangled photons.

  9. Lithography using quantum entangled particles

    NASA Technical Reports Server (NTRS)

    Williams, Colin (Inventor); Dowling, Jonathan (Inventor)

    2001-01-01

    A system of etching using quantum entangled particles to get shorter interference fringes. An interferometer is used to obtain an interference fringe. N entangled photons are input to the interferometer. This reduces the distance between interference fringes by n, where again n is the number of entangled photons.

  10. Light as a Fundamental Particle

    ERIC Educational Resources Information Center

    Weinberg, Steven

    1975-01-01

    Presents two arguments concerning the role of the photon. One states that the photon is just another particle distinguished by a particular value of charge, spin, mass, lifetime, and interaction properties. The second states that the photon plays a fundamental role with a deep relation to ultimate formulas of physics. (GS)

  11. MODELING DEPOSITION OF INHALED PARTICLES

    EPA Science Inventory

    Modeling Deposition of Inhaled Particles: ABSTRACT

    The mathematical modeling of the deposition and distribution of inhaled aerosols within human lungs is an invaluable tool in predicting both the health risks associated with inhaled environmental aerosols and the therapeut...

  12. A Parallel Particle Swarm Optimizer

    DTIC Science & Technology

    2003-01-01

    by a computationally demanding biomechanical system identification problem, we introduce a parallel implementation of a stochastic population based...concurrent computation. The parallelization of the Particle Swarm Optimization (PSO) algorithm is detailed and its performance and characteristics demonstrated for the biomechanical system identification problem as example.

  13. Migrational Instabilities in Particle Suspensions

    NASA Technical Reports Server (NTRS)

    Goddard, Joe D.

    1996-01-01

    This work deals with an instability arising from the shear-induced migration of particles in dense suspensions coupled with a dependence of viscosity on particle concentration. The analysis summarized here treats the inertialess (Re = O) linear stability of homogeneous simple shear flows for a Stokesian suspension model of the type proposed by Leighton and Acrivos (1987). Depending on the importance of shear-induced migration relative to concentration-driven diffusion, this model admits short-wave instability arising from wave-vector stretching by the base flow and evolving into particle-depleted shear bands. Moreover, this instability in the time-dependent problem corresponds to loss of ellipticity in the associated static problem (Re = O, Pe = O). While the isotropic version of the Leighton-Acrivos model is found to be stable with their experimentally determined parameters for simple shear, it is known that the stable model does not give a good quantitative description of particle clustering in the core of pipe flow (Nott and Brady 1994). This leads to the conjecture that an appropriate variant on the above model could explain such clustering as a two-phase bifurcation in the base flow.

  14. Particle Acceleration in Relativistic Outflows

    NASA Technical Reports Server (NTRS)

    Bykov, Andrei; Gehrels, Neil; Krawczynski, Henric; Lemoine, Martin; Pelletier, Guy; Pohl, Martin

    2012-01-01

    In this review we confront the current theoretical understanding of particle acceleration at relativistic outflows with recent observational results on various source classes thought to involve such outflows, e.g. gamma-ray bursts, active galactic nuclei, and pulsar wind nebulae. We highlight the possible contributions of these sources to ultra-high-energy cosmic rays.

  15. Particle and flow field holography

    NASA Astrophysics Data System (ADS)

    Trolinger, J. D.

    1985-01-01

    The current status of particle field and flow field holography is examined, and the methods based on the principles of either class of imagery are described. Special consideration is given to the automated data reduction technology. Current applications of flow diagnostics, which can provide thousands of holograms during a one-day experiment, include NASA applications in wind tunnel holography, in a Laser Doppler Velocimeter, in holographic movies, and in an optical device for recording crystal growth at zero gravity, to be used in the Space Lab 3 shuttle mission scheduled for May 1985. Military applications of the flow diagnostics include the use of holographic tomography for visualizing flow fields around airborne structures, in wind tunnels, and in the analyses of rocket exhausts and gun ranges. The information provided by the particle sizing holography, concerning the size, shape, number, and velocity of particles and the records of the particle break-up phenomenon, can be used in various military field oriented and airborne applications and in meteorology and environment protection science.

  16. Particle radiotherapy for prostate cancer.

    PubMed

    Shioyama, Yoshiyuki; Tsuji, Hiroshi; Suefuji, Hiroaki; Sinoto, Makoto; Matsunobu, Akira; Toyama, Shingo; Nakamura, Katsumasa; Kudo, Sho

    2015-01-01

    Recent advances in external beam radiotherapy have allowed us to deliver higher doses to the tumors while decreasing doses to the surrounding tissues. Dose escalation using high-precision radiotherapy has improved the treatment outcomes of prostate cancer. Intensity-modulated radiation therapy has been widely used throughout the world as the most advanced form of photon radiotherapy. In contrast, particle radiotherapy has also been under development, and has been used as an effective and non-invasive radiation modality for prostate and other cancers. Among the particles used in such treatments, protons and carbon ions have the physical advantage that the dose can be focused on the tumor with only minimal exposure of the surrounding normal tissues. Furthermore, carbon ions also have radiobiological advantages that include higher killing effects on intrinsic radio-resistant tumors, hypoxic tumor cells and tumor cells in the G0 or S phase. However, the degree of clinical benefit derived from these theoretical advantages in the treatment of prostate cancer has not been adequately determined. The present article reviews the available literature on the use of particle radiotherapy for prostate cancer as well as the literature on the physical and radiobiological properties of this treatment, and discusses the role and the relative merits of particle radiotherapy compared with current photon-based radiotherapy, with a focus on proton beam therapy and carbon ion radiotherapy.

  17. Methylecgonidine coats the crack particle.

    PubMed

    Wood, R W; Shojaie, J; Fang, C P; Graefe, J F

    1996-01-01

    Crack is a form of cocaine base self-administered by smoking. When heated, it volatilizes and may partially pyrolyze to methylecgonidine (MEG). Upon cooling, a condensation aerosol forms. Heating cocaine base in model crack pipes produced particles of about 1 micron in diameter, regardless of the amount heated; however, MEG concentration increased from < or = 2% at 10 mg per heating to as much as 5% at 30 mg per heating. Methylecgonidine was < or = 1% of the recovered material when cocaine was vaporized off a heated wire coil, but the particles were larger (2-5 microns), and the distribution disperse. The vapor pressure of MEG was higher [log P(mm Hg) = 9.994 - 3530/T] than cocaine base, consistent with MEG coating the droplet during condensation, and with evaporation during aging or dilution. Disappearance of MEG from a chamber filled with crack smoke was a two-component process, one proceeding at the rate of cocaine particle removal, and the other at the desorption rate from other surfaces. Particle diameter influences the deposition site in the respiratory tract; thus, the likely different patterns of deposition in the respiratory tract of humans and animals of crack aerosols produced by different techniques warrant consideration, as they may influence our understanding of immediate and delayed sequelae of the inhalation of cocaine and its pyrolysis product, MEG.

  18. New Techniques for Particle Acclerators

    SciTech Connect

    Sessler, Andrew M.

    1990-06-01

    A review is presented of the new techniques which have been proposed for use in particle accelerators. Attention is focused upon those areas where significant progress has been made in the last two years--in particular, upon two-beam accelerators, wakefield accelerators, and plasma focusers.

  19. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1984-01-01

    The astrophysical aspects of cosmic rays and gamma rays and of the electromagnetic field environment of the Earth and other planets are investigated. These investigations are carried out by means of energetic particle and photon detector systems flown on spacecraft and balloons.

  20. Particle-vortex symmetric liquid

    NASA Astrophysics Data System (ADS)

    Mulligan, Michael

    2017-01-01

    We introduce an effective theory with manifest particle-vortex symmetry for disordered thin films undergoing a magnetic field-tuned superconductor-insulator transition. The theory may enable one to access both the critical properties of the strong-disorder limit, which has recently been confirmed by Breznay et al. [Proc. Natl. Acad. Sci. USA 113, 280 (2016), 10.1073/pnas.1522435113] to exhibit particle-vortex symmetric electrical response, and the nearby metallic phase discovered earlier by Mason and Kapitulnik [Phys. Rev. Lett. 82, 5341 (1999), 10.1103/PhysRevLett.82.5341] in less disordered samples. Within the effective theory, the Cooper-pair and field-induced vortex degrees of freedom are simultaneously incorporated into an electrically neutral Dirac fermion minimally coupled to a (emergent) Chern-Simons gauge field. A derivation of the theory follows upon mapping the superconductor-insulator transition to the integer quantum Hall plateau transition and the subsequent use of Son's particle-hole symmetric composite Fermi liquid. Remarkably, particle-vortex symmetric response does not require the introduction of disorder; rather, it results when the Dirac fermions exhibit vanishing Hall effect. The theory predicts approximately equal (diagonal) thermopower and Nernst signal with a deviation parameterized by the measured electrical Hall response at the symmetric point.

  1. Of people, particles and prejudice

    NASA Astrophysics Data System (ADS)

    Jackson, Penny; Greene, Anne; Mears, Matt; Spacecadet1; Green, Christian; Hunt, Devin J.; Berglyd Olsen, Veronica K.; Ilya, Komarov; Pierpont, Elaine; Gillman, Matthew

    2016-05-01

    In reply to Louise Mayor's feature article “Where people and particles collide”, about the experiences of researchers at CERN who are lesbian, gay, bisexual or transgender (LGBT), efforts to make LGBT CERN an officially recognized club, and incidents where posters advertising the club have been torn down or defaced (March pp31-36, http://ow.ly/YVP2Z).

  2. Diffusion in jammed particle packs

    NASA Astrophysics Data System (ADS)

    Bolintineanu, Dan S.; Silbert, Leonardo E.; Grest, Gary S.; Lechman, Jeremy B.

    2015-03-01

    Diffusive transport in jammed particle packs is of interest for a number of applications, as well as being a potential indicator of structural properties near the jamming point. To this end, we report stochastic simulations of equilibrium diffusion through monodisperse sphere packs near the jamming point in the limit of a perfectly insulating surrounding medium. The time dependence of various diffusion properties is resolved over several orders of magnitude. Two time regimes of expected Fickian diffusion are observed, separated by an intermediate regime of anomalous diffusion. This intermediate regime grows as the particle volume fraction approaches the critical jamming transition. The diffusion behavior is fully controlled by the extent of the contacts between neighboring particles, which in turn depend on proximity to the jamming point. In particular, the mean first passage time associated with the escape of random walkers between neighboring particles is shown to control both the time to recover Fickian diffusion and the long time diffusivity. Scaling laws are established that relate these quantities to the difference between the actual and critical jamming volume fractions. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under Contract DE- AC04-94AL85000.

  3. Engineered plant biomass feedstock particles

    DOEpatents

    Dooley, James H.; Lanning, David N.; Broderick, Thomas F.

    2011-10-11

    A novel class of flowable biomass feedstock particles with unusually large surface areas that can be manufactured in remarkably uniform sizes using low-energy comminution techniques. The feedstock particles are roughly parallelepiped in shape and characterized by a length dimension (L) aligned substantially with the grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. The particles exhibit a disrupted grain structure with prominent end and surface checks that greatly enhances their skeletal surface area as compared to their envelope surface area. The L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers. The W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers. The L.times.W dimensions define a pair of substantially parallel top surfaces characterized by some surface checking between longitudinally arrayed fibers. The feedstock particles are manufactured from a variety of plant biomass materials including wood, crop residues, plantation grasses, hemp, bagasse, and bamboo.

  4. Health benefits of particle filtration

    EPA Science Inventory

    This product was developed under an interagency agreement between the U.S. EPA and the U.S. Department of Energy - Lawrence Berkeley National Laboratory (LBNL). The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews o...

  5. Alpha particle emitters in medicine

    SciTech Connect

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.

  6. Fine Particle Scrubbing: A Proceedings

    ERIC Educational Resources Information Center

    Journal of the Air Pollution Control Association, 1974

    1974-01-01

    These articles deal with the proceedings of a 1974 symposium on the use of wet scrubbers for the control of fine particle air pollutants. Various wet scrubbers, their engineering, performance, efficiency, and future are discussed. Tables, formulas, and models are included. (TK)

  7. Introduction to Elementary Particle Physics

    NASA Astrophysics Data System (ADS)

    Salinas, C. J. Solano; Hurtado, K.; Romero, C.

    2009-04-01

    This is a short review of Particle Physics and the most widely accepted theory, the Standard Model, with its questions and limitations. We also show a quick review of some of te theories beyonf the Standard Model. It is based in the introductory talk given the Third School on Cosmic Rays and Astrophysics held in Arequipa, Peru.

  8. Particle-particle, particle-scaling function algorithm for electrostatic problems in free boundary conditions.

    PubMed

    Neelov, Alexey; Ghasemi, S Alireza; Goedecker, Stefan

    2007-07-14

    An algorithm for fast calculation of the Coulombic forces and energies of point particles with free boundary conditions is proposed. Its calculation time scales as N log N for N particles. This novel method has lower crossover point with the full O(N(2)) direct summation than the fast multipole method. The forces obtained by our algorithm are analytical derivatives of the energy which guarantees energy conservation during a molecular dynamics simulation. Our algorithm is very simple. A version of the code parallelized with the Message Passing Interface can be downloaded under the GNU General Public License from the website of our group.

  9. Research in Elementary Particle Physics

    SciTech Connect

    White, Andrew Paul; De, Kaushik; Brandt, Andrew; Yu, Jaehoon; Farbin, Amir

    2015-02-02

    This report details the accomplishments and research results for the High Energy Physics Group at the University of Texas at Arlington at the Energy and Intensity Frontiers. For the Energy Frontier we have made fundamental contributions in the search for supersymmetric particles, proposed to explain the stabilization of the mass of the Higgs Boson – the agent giving mass to all known particles. We have also made major contributions to the search for additional Higgs Bosons and to the planning for future searches. This work has been carried out in the context of the ATLAS Experiment at CERN (European Nuclear Research Laboratory) and for which we have made major contributions to computing and data distribution and processing, and have worked to calibrate the detector and prepare upgraded electronics for the future. Our other contribution to the Energy Frontier has been to the International Linear Collider (ILC) project, potentially hosted by Japan, and to the Silicon Detector Concept (SiD) in particular. We have lead the development of the SiD Concept and have worked on a new form of precise energy measurement for particles from the high energy collisions of electrons and positrons at the ILC. For the Intensity Frontier, we have worked to develop the concept of Long Baseline Neutrino Experiment(s) (LBNE) at the Fermi National Accelerator Laboratory. Our contributions to detector development, neutrino beam studies, particle identification, software development will facilitate future studies of the oscillation of one type of neutrino into other type(s), establish the order of the neutrino masses, and, through an innovative new idea, allow us to create a beam of dark matter particles.

  10. Nanotechnology: Colourful Particles for Spectrometry

    SciTech Connect

    Anheier, Norman C.

    2015-07-01

    In 1857 Michael Faraday gave a well-attended lecture at the Royal Institution of Great Britain, in which he presented his pioneering experimental work that investigated the interaction of light with matter. Faraday’s study probed the fundamental properties of light as it was reflected and absorbed by progressively smaller particles. Very fine gold particles dispersed in liquid were shown to produce vivid colors not seen in larger particles. Faraday did not know he had created colloidal suspensions of quantum dots, but his insight correctly concluded that the distinct colors were somehow due to the minute size of the gold particles. This great experimental physicist had actually glimpsed a special condition where the particle’s quantum nature was expressed. This work set the future course for nanoscience and quantum theory, but it would take another 125 years before the physical basis of this phenomenon would be explained by quantum size effects. It is now known that when quantum dots are exposed to UV light, some of the electrons are excited as they gain energy, however they remain confined to discrete energy levels not observed in larger particles and solid materials. When the electrons relax and lose their energy, the quantum dot emits light at a specific color that varies with the size of the quantum dot. Bao and Bawendi have cleverly exploited the unique optical properties intrinsic to colloidal quantum dots to develop an innovative compact optical spectrometer that could be integrated with a smart phone camera or as a versatile miniature handheld sensing tool.

  11. Sustainment of Fine Particle Cloud by Means of Time-Averaged Particle Driving Force in Plasmas

    SciTech Connect

    Gohda, Takuma; Iizuka, Satoru

    2008-09-07

    We have succeeded in sustaining fine particle cloud by using a time-averaged particle driving (TAPD) method in the RF discharge plasma. The particles feel only time-averaged force when the period of pulses applied to those point-electrodes is shorter than the particle response time. The particles are transported to a middle point between two point-electrodes.

  12. Particles, particle labels, and quanta: The toll of unacknowledged metaphysics

    SciTech Connect

    Redhead, M. ); Teller, P. )

    1991-01-01

    The practice of describing multiparticle quantum systems in terms of labeled particles indicates that the authors think of quantum entities as individuatable. The labels, together with particle indistinguishability, create the need for symmetrization or antisymmetrization (or, in principle, higher-order symmetries), which in turn results in surplus formal structure' in the formalism, formal structure which corresponds to nothing in the real world. The authors argue that these facts show quanta to be unindividuatable entities, things in principle incapable of supporting labels, and so things which support no factual difference if two of them are thought of as being switched. When thinking of the metaphysics of quanta, one should eschew the misleading labels of the tensor product Hilbert space formalism and prefer the ontologically more faithful description of the Fock space formalism. This conception eliminates puzzles about the quantum statistics of bosons.

  13. Elementary Particles and the Universe Elementary Particles and the Universe

    NASA Astrophysics Data System (ADS)

    Schwarz, John H.

    1991-10-01

    Professor Murray Gell-Mann is one of the most influential and brilliant scientists of the twentieth century. His work on symmetries, including the invention of the "quark," in the 1950s and early 1960s provided the foundation for much of modern particle physics. His contribution to the field earned him the Nobel Prize for Physics in 1969. This book is a collection of research articles by eminent scientists written especially to celebrate Gell-Mann's 60th birthday, in September 1989. The main body of contributions is concerned with theoretical particle physics and its applications to cosmology, and includes papers by such notables as J. Hartle, E. Witten, H. Fritzsch, T.D. Lee, I.M. Singer, V. Telegdi, and some personal remarks by A. Salam and M.L. Goldberger.

  14. Multi-particle inspection using associated particle sources

    DOEpatents

    Bingham, Philip R.; Mihalczo, John T.; Mullens, James A.; McConchie, Seth M.; Hausladen, Paul A.

    2016-02-16

    Disclosed herein are representative embodiments of methods, apparatus, and systems for performing combined neutron and gamma ray radiography. For example, one exemplary system comprises: a neutron source; a set of alpha particle detectors configured to detect alpha particles associated with neutrons generated by the neutron source; neutron detectors positioned to detect at least some of the neutrons generated by the neutron source; a gamma ray source; a set of verification gamma ray detectors configured to detect verification gamma rays associated with gamma rays generated by the gamma ray source; a set of gamma ray detectors configured to detect gamma rays generated by the gamma ray source; and an interrogation region located between the neutron source, the gamma ray source, the neutron detectors, and the gamma ray detectors.

  15. A new experiment to measure shocked particle drag using multi-pulse particle image velocimetry and particle tracking

    NASA Astrophysics Data System (ADS)

    Martinez, Adam A.; Orlicz, Gregory C.; Prestridge, Katherine P.

    2015-01-01

    We demonstrate the measurement capabilities for a new horizontal shock tube facility designed to measure the displacements, velocities and accelerations of shock-accelerated particles just after shock passage. Eight-frame particle image accelerometry and particle tracking velocimetry accelerometry diagnostics are implemented, along with a shadowgraphy system for measuring the shock location during experiments. We demonstrate the driving conditions of the facility using a unique membraneless pneumatic driver and particle seeding system that can accommodate both solid and liquid particles in the carrier phase. Measurements of two types of solid particles show unsteady drag forces higher than those for steady drag.

  16. On the Relation of Wave-Particle Interactions, Particle Dynamics, and Suprathermal Particle Distributions

    NASA Astrophysics Data System (ADS)

    Kucharek, Harald; Galvin, Antoinette; Farrugia, Charles; Klecker, Berndt; Pogorelov, Nikolai

    2016-04-01

    Wave-particle interactions, ion acceleration, and magnetic turbulence are closely interlinked and the physical processes may occur on different scales. These scales range from the kinetic scale to the macro-scale (MHD-scale). These processes are likely universal and the same basic processes occur at the Earth's environment, at the Earth's bow shock, the solar wind, and around the heliosphere. Undoubtedly, the Earth's environment as well as the close interplanetary space are the best plasma environments to study these processes using satellite measurements. Recently, ACE, STEREO, IBEX and Voyager observations clearly showed that turbulence and wave-particle interactions and turbulence are extremely important in interplanetary space and in the heliosphere. Using data from STEREO, Wind, we have investigated the spectral properties of suprathermal ion distributions. The results show that spectral slopes are very variable and depend on the plasma properties. We have also performed 3D hybrid simulations and studied particle dynamics. These simulations show that the particle dynamics in the turbulent magnetic wave field is Levy-Flight like which leads to a kappa distribution, which is often found in various space environments. This result is very significant of future mission such as THOR and IMAP and current operating missions such as STEREO, IBEX, and MMS.

  17. Circular, confined distribution for charged particle beams

    DOEpatents

    Garnett, Robert W.; Dobelbower, M. Christian

    1995-01-01

    A charged particle beam line is formed with magnetic optics that manipulate the charged particle beam to form the beam having a generally rectangular configuration to a circular beam cross-section having a uniform particle distribution at a predetermined location. First magnetic optics form a charged particle beam to a generally uniform particle distribution over a square planar area at a known first location. Second magnetic optics receive the charged particle beam with the generally square configuration and affect the charged particle beam to output the charged particle beam with a phase-space distribution effective to fold corner portions of the beam toward the core region of the beam. The beam forms a circular configuration having a generally uniform spatial particle distribution over a target area at a predetermined second location.

  18. Circular, confined distribution for charged particle beams

    DOEpatents

    Garnett, R.W.; Dobelbower, M.C.

    1995-11-21

    A charged particle beam line is formed with magnetic optics that manipulate the charged particle beam to form the beam having a generally rectangular configuration to a circular beam cross-section having a uniform particle distribution at a predetermined location. First magnetic optics form a charged particle beam to a generally uniform particle distribution over a square planar area at a known first location. Second magnetic optics receive the charged particle beam with the generally square configuration and affect the charged particle beam to output the charged particle beam with a phase-space distribution effective to fold corner portions of the beam toward the core region of the beam. The beam forms a circular configuration having a generally uniform spatial particle distribution over a target area at a predetermined second location. 26 figs.

  19. How Actuated Particles Effectively Capture Biomolecular Targets

    PubMed Central

    2017-01-01

    Because of their high surface-to-volume ratio and adaptable surface functionalization, particles are widely used in bioanalytical methods to capture molecular targets. In this article, a comprehensive study is reported of the effectiveness of protein capture by actuated magnetic particles. Association rate constants are quantified in experiments as well as in Brownian dynamics simulations for different particle actuation configurations. The data reveal how the association rate depends on the particle velocity, particle density, and particle assembly characteristics. Interestingly, single particles appear to exhibit target depletion zones near their surface, caused by the high density of capture molecules. The depletion effects are even more limiting in cases with high particle densities. The depletion effects are overcome and protein capture rates are enhanced by applying dynamic particle actuation, resulting in an increase in the association rate constants by up to 2 orders of magnitude. PMID:28192952

  20. CFD development for macro particle simulations

    NASA Astrophysics Data System (ADS)

    Zhao, Xiang; Glenn, Chance; Xiao, Zhigang; Zhang, Sijun

    2014-05-01

    Numerous industrial operations involve fluid-particle systems, in which both phases display very complex behaviour. Some examples include fluidisation technology in catalytic reactors, pneumatic transportation of grain or powder materials, carbon nanotube alignment in the nano-devices and circuit integration and so on. In this paper, a macro particle method is developed to model the fluid-particle flows. The macro particle is formed by a collection of micro-sized particles so that the number of macro particles to be tracked is much less than the number of smaller particles. Unlike the calculations of instantaneous point variables of fluid phase with moving discrete boundaries of the smaller particles with direct numerical simulation, the boundary of each macro particle is just dealt with the blocked-off approach. On the other hand, the flow fields based on the present method is solved by original Navier-Stokes, rather than the modified ones based on the locally averaged theorem. The flow fields are solved on the length scale of computational cells, while the resolutions of solid particles are the size of macro particle, which is determined as needed in specific applications. The macro particle method is validated by several selected cases, which demonstrate that the macro particle method could accurately resolve fluid-particle systems in an efficient, robust and flexible fashion.

  1. Selective particle capture by asynchronously beating cilia

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Kanso, Eva

    2015-12-01

    Selective particle filtration is fundamental in many engineering and biological systems. For example, many aquatic microorganisms use filter feeding to capture food particles from the surrounding fluid, using motile cilia. One of the capture strategies is to use the same cilia to generate feeding currents and to intercept particles when the particles are on the downstream side of the cilia. Here, we develop a 3D computational model of ciliary bands interacting with flow suspended particles and calculate particle trajectories for a range of particle sizes. Consistent with experimental observations, we find optimal particle sizes that maximize capture rate. The optimal size depends nonlinearly on cilia spacing and cilia coordination, synchronous vs. asynchronous. These parameters affect the cilia-generated flow field, which in turn affects particle trajectories. The low capture rate of smaller particles is due to the particles' inability to cross the flow streamlines of neighboring cilia. Meanwhile, large particles have difficulty entering the sub-ciliary region once advected downstream, also resulting in low capture rates. The optimal range of particle sizes is enhanced when cilia beat asynchronously. These findings have potentially important implications on the design and use of biomimetic cilia in processes such as particle sorting in microfluidic devices.

  2. Correlation studies on surface particle detection methods

    NASA Technical Reports Server (NTRS)

    Peterson, Ronald V.; White, James C.

    1988-01-01

    The accurate determination of dust levels on optical surfaces is necessary to assess sensor system performance. A comparison study was made on several particle measurement methods including those based on direct imaging and light scattering. The effectiveness of removing the particles from the surface prior to determining particle size distributions was also assessed. These studies revealed that some methods, especially those requiring particle removal before analysis, are subject to large systematic errors affecting particle size distributions. Thus, an understanding of the particle measurement methods employed is necessary before any surface cleanliness or obstruction value assignments are accepted as true representations of an optical surface contamination condition.

  3. Multi-physics/scale simulations using particles

    NASA Astrophysics Data System (ADS)

    Koumoutsakos, Petros

    2006-03-01

    Particle simulations of continuum and discrete phenomena can be formulated by following the motion of interacting particles that carry the physical properties of the systems that is being approximated (continuum) or modeled (discrete) by the particles. We identify the common computational characteristics of particle methods and emphasize their key properties that enable the formulation of a novel, systematic framework for multiscale simulations, that can be applicable to the simulation of diverse physical problems. We present novel multiresolution particle methods for continuum (fluid/solid) simulations, using adaptive mesh refinement and wavelets, by relaxing the grid-free character of particle methods and discuss the coupling of scales in continuum-atomistic flow simulations.

  4. Quantum limited particle sensing in optical tweezers

    SciTech Connect

    Tay, J.W.; Hsu, Magnus T. L.; Bowen, Warwick P.

    2009-12-15

    Particle sensing in optical tweezers systems provides information on the position, velocity, and force of the specimen particles. The conventional quadrant detection scheme is applied ubiquitously in optical tweezers experiments to quantify these parameters. In this paper, we show that quadrant detection is nonoptimal for particle sensing in optical tweezers and propose an alternative optimal particle sensing scheme based on spatial homodyne detection. A formalism for particle sensing in terms of transverse spatial modes is developed and numerical simulations of the efficacies of both quadrant and spatial homodyne detection are shown. We demonstrate that 1 order of magnitude improvement in particle sensing sensitivity can be achieved using spatial homodyne over quadrant detection.

  5. Powder fed sheared dispersal particle generator

    NASA Technical Reports Server (NTRS)

    Morrisette, E. L.; Bushnell, D. M. (Inventor)

    1984-01-01

    A particle generating system is described which is capable of breaking up agglomerations of particles and producing a cloud of uniform, submicron-sized particles at high pressure and high flow rates. This is achieved by utilizing a tubular structure which has injection microslits on is periphery to accept and disperse the desired particle feed. By suppling a carrying fluid at a pressure, of approximately twice the ambient pressure of the velocimeter's settling chamber, the microslits operate at choked flow conditions. The shearing action of this choked flow is sufficient to overcome interparticle bonding forces, thereby breaking up the agglomerates of the particles feed into individual particles.

  6. Electrical charge measurements on fine airborne particles

    SciTech Connect

    Tardos, G.I.; Dietz, P.W.; Snaddon, R.W.L.

    1984-11-01

    A small parallel-plate precipitator and a theoretical collection model have been used to determine the distribution of charges acquired by monodisperse airborne polystyrene latex particles in a corona charger. The mean charge based on the total number of particles was found to be slightly higher than half the predicted saturation charge, and it agreed well with independent measurements made in a Faraday cage particle separator. The importance of careful measurements of particle charge in fine particle transport studies is highlighted by a discussion of the effect of charge (particle mobility) distribution width on observed transport characteristics.

  7. Preliminary Measurement of Lunar Particle Shapes.

    NASA Technical Reports Server (NTRS)

    Rickman, Doug

    2013-01-01

    Particle shape is a basic parameter and essential for many engineering applications. Very little data is published on the shape of lunar particles. An unpublished review found that even where the same samples were studied the results were contradictory, probably because of extremely small sample sizes. Other workers have made fundamental errors in algorithms. There are many ways to measure particle shape. One common approach is to examine the particles as intersected by a plain, such as a thin section. If discrete particles can be segmented from the image, programs such as ImageJ can readily obtain shape measurements for each particle.

  8. DNA-Grafted Janus Particles

    NASA Astrophysics Data System (ADS)

    Hsueh, Ching; Lin, Keng-Hui; Juan, Wen-Tau

    2008-03-01

    Recently there have been advances in generating Janus microspheres whose two hemispheres have different chemical compositions [1-4]. The new types of particles open up possibilities for assembly of complex structures. Here we attach DNA molecules onto one side of Janus microspheres. The new type of colloidal particles resembles surfactant molecules and may give us interesting new structures.Reference: [1] Y. Lu, H. Xiong, X. Jiang, Y.Xia, M. Prentiss and G. M.Whitesides, J. Am. Chem. Soc. 125, 12724 (2003) [2] O.Cayre, V. N.Paunov and O. D. Velev, J. Mater. Chem. 13, 2445 (2003) [3] R. F. Shepherd, J. C. Conrad, S. K. Rhodes, D. R. Link, M. Marquez, D. A. Weitz and J. A. Lewis, Langmuir 22, 8618 (2006) [4] L. Hong, S. Jiang and S. Granick, Langmuir 22, 9495 (2006)

  9. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  10. Elasticity of polymeric nanocolloidal particles

    NASA Astrophysics Data System (ADS)

    Riest, Jonas; Athanasopoulou, Labrini; Egorov, Sergei A.; Likos, Christos N.; Ziherl, Primož

    2015-11-01

    Softness is an essential mechanical feature of macromolecular particles such as polymer-grafted nanocolloids, polyelectrolyte networks, cross-linked microgels as well as block copolymer and dendrimer micelles. Elasticity of individual particles directly controls their swelling, wetting, and adsorption behaviour, their aggregation and self-assembly as well as structural and rheological properties of suspensions. Here we use numerical simulations and self-consistent field theory to study the deformation behaviour of a single spherical polymer brush upon diametral compression. We observe a universal response, which is rationalised using scaling arguments and interpreted in terms of two coarse-grained models. At small and intermediate compressions the deformation can be accurately reproduced by modelling the brush as a liquid drop, whereas at large compressions the brush behaves as a soft ball. Applicable far beyond the pairwise-additive small-strain regime, the models may be used to describe microelasticity of nanocolloids in severe confinement including dense disordered and crystalline phases.

  11. Optoelectronic Particle-Fallout Sensor

    NASA Technical Reports Server (NTRS)

    Ihlefeld, Curtis; Mogan, Paul A.; Youngquist, Robert C.; Moerk, John S.; Haskell, William D.; Cox, Robert B.; Rose, Kenneth A.

    1995-01-01

    Portable optoelectronic system monitors fallout of small particles (dust and fibers) onto surface at given location during extended time. Data on accumulated fallout downloaded from system to computer for display and analysis. Typical display is plot of signal proportional to amount of accumulated fallout as function of time and read to determine when contamination occurs. In many cases, possible to establish correlations between accumulations of particles and activities in vicinity. Also capable of signaling alarm in event contamination by fallout exceeds specified level. System made very inexpensively and used to monitor accumulation of dust and fibers associated with motion of air in variety of environments. Phenomena monitored indirectly by use of system might include circulation of air in buildings, and human and animal activity. Also serves as auxiliary intrusion monitor (though probably not real-time alarm) in sealed room because motion of intruder inevitably stirs up some dust.

  12. Nanorice Particles: Hybrid Plasmonic Nanostructures

    NASA Technical Reports Server (NTRS)

    Wang, Hui (Inventor); Brandl, Daniel (Inventor); Le, Fei (Inventor); Nordlander, Peter (Inventor); Halas, Nancy J. (Inventor)

    2010-01-01

    A new hybrid nanoparticle, i.e., a nanorice particle, which combines the intense local fields of nanorods with the highly tunable plasmon resonances of nanoshells, is described herein. This geometry possesses far greater structural tunability than previous nanoparticle geometries, along with much larger local field enhancements and far greater sensitivity as a surface plasmon resonance (SPR) nanosensor than presently known dielectric-conductive material nanostructures. In an embodiment, a nanoparticle comprises a prolate spheroid-shaped core having a first aspect ratio. The nanoparticle also comprises at least one conductive shell surrounding said prolate spheroid-shaped core. The nanoparticle has a surface plasmon resonance sensitivity of at least 600 nm RIU(sup.-1). Methods of making the disclosed nanorice particles are also described herein.

  13. Extreme solar energetic particle events

    NASA Astrophysics Data System (ADS)

    Vainio, Rami; Afanasiev, Alexandr; Battarbee, Markus

    2016-04-01

    Properties of extreme solar energetic particle (SEP) events, here defined as those leading to ground level enhancements (GLEs) of cosmic rays, are reviewed. We review recent efforts on modeling SEP acceleration to relativistic energies and present simulation results on particle acceleration at shocks driven by fast coronal mass ejections (CMEs) in different types of coronal magnetic structures and turbulent downstream compression regions. Based on these modeling results, we discuss the possible role of solar and CME parameters in the lack of GLEs during the present sunspot cycle. This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324 (HESPERIA). The Academy of Finland is thanked for financial support.

  14. Sampler of gas borne particles

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Stephens, J. B. (Inventor)

    1976-01-01

    An atmosphere sample is described which includes a very thin filter element with straight-through holes on the order of 1 micron. A sample of air with particles to be examined is driven by means of a pressurized low molecular weight gas, e.g., He to the filter element front side. A partial vacuum may be present at the back side of the filter element. The pressure differential across the filter element is just below the rupture point of the filter element. Particles smaller than filter holes are deposited on the filter element. When using a filter element of plastic material of a thickness on the order of 10 microns, a stainless steel back-up plate and a diffusion member are used to support the filter element when subjected to a pressure differential on the order of a few hundred atmospheres.

  15. Process to make structured particles

    SciTech Connect

    Knapp, Angela Michelle; Richard, Monique N; Luhrs, Claudia; Blada, Timothy; Phillips, Jonathan

    2014-02-04

    Disclosed is a process for making a composite material that contains structured particles. The process includes providing a first precursor in the form of a dry precursor powder, a precursor liquid, a precursor vapor of a liquid and/or a precursor gas. The process also includes providing a plasma that has a high field zone and passing the first precursor through the high field zone of the plasma. As the first precursor passes through the high field zone of the plasma, at least part of the first precursor is decomposed. An aerosol having a second precursor is provided downstream of the high field zone of the plasma and the decomposed first material is allowed to condense onto the second precursor to from structured particles.

  16. Elementary Particles and the Universe

    NASA Astrophysics Data System (ADS)

    Schwarz, John H.

    1991-10-01

    Professor Murray Gell-Mann is one of the most influential and brilliant scientists of the twentieth century. His work on symmetries, including the invention of the "quark," in the 1950s and early 1960s provided the foundation for much of modern particle physics. His contribution to the field earned him the Nobel Prize for Physics in 1969. This book is a collection of research articles by eminent scientists written especially to celebrate Gell-Mann's 60th birthday, in September 1989. The main body of contributions is concerned with theoretical particle physics and its applications to cosmology, and includes papers by such notables as J. Hartle, E. Witten, H. Fritzsch, T.D. Lee, I.M. Singer, V. Telegdi, and some personal remarks by A. Salam and M.L. Goldberger.

  17. Functional colloidal particles for immunoresearch

    NASA Technical Reports Server (NTRS)

    Yen, S. P. S.; Rembaum, A.; Molday, R. W.; Dreyer, W.

    1976-01-01

    The paper deals with the development of a new class of immunological reagents consisting of antibodies covalently bonded to polymeric microspheres to serve as convenient markers for detection of cell surface antigens by scanning electron and light microscopy. Attention is focused on the design and synthesis of spherical particles containing hydroxyl and carboxyl groups on their surface in a wide range of sizes (30-340 nm diam) by emulsion copolymerization, the preparation of spherical particles ranging from 300 nm to 3 microns and containing a variety of functional groups by means of ionizing radiation, and the experimental conditions for the covalent bonding of fluorescent molecules and antibodies to the spheres by means of the cyanogen bromide, carbodiimide and glutaraldehyde methods. These reagents are used to locate antigens on red blood cells, on mouse and human lymphocytes, and on the surface of photoreceptors. They offer a number of advantages and applications for the study of cell surfaces for immunodiagnosis.

  18. Discretization errors in particle tracking

    NASA Astrophysics Data System (ADS)

    Carmon, G.; Mamman, N.; Feingold, M.

    2007-03-01

    High precision video tracking of microscopic particles is limited by systematic and random errors. Systematic errors are partly due to the discretization process both in position and in intensity. We study the behavior of such errors in a simple tracking algorithm designed for the case of symmetric particles. This symmetry algorithm uses interpolation to estimate the value of the intensity at arbitrary points in the image plane. We show that the discretization error is composed of two parts: (1) the error due to the discretization of the intensity, bD and (2) that due to interpolation, bI. While bD behaves asymptotically like N-1 where N is the number of intensity gray levels, bI is small when using cubic spline interpolation.

  19. Boron doping a semiconductor particle

    DOEpatents

    Stevens, Gary Don; Reynolds, Jeffrey Scott; Brown, Louanne Kay

    1998-06-09

    A method (10,30) of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried (16), with the boron film then being driven (18) into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out (38) into piles and melted/fused (40) with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements.

  20. Boron doping a semiconductor particle

    DOEpatents

    Stevens, G.D.; Reynolds, J.S.; Brown, L.K.

    1998-06-09

    A method of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried, with the boron film then being driven into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out into piles and melted/fused with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements. 2 figs.

  1. Study of flow field of burning particles in a pyrotechnic flame based on particle image and particle velocity

    NASA Astrophysics Data System (ADS)

    Xue, R.; Xu, H. Q.; Li, Y.; Zhu, C. G.

    2014-11-01

    Studying the burning particles in the pyrotechnic flame is important to acquire the decomposition mechanism and spectral radiance of pyrotechnics. The high speed video (HSV) and particle image velocimetry (PIV) were used in this paper to analyze the flow field and velocity of burning particles in the flame of pyrotechnics. The binary image was obtained through gray scale treatment and adaptive threshold segmentation from HSV and PIV data, by which the coordinate of each particle was marked. On the basis, the movement trajectory of each particle during combustion was pursued by the most recent guidelines algorithm of cancroids matching. Through the method proposed in this study, the velocity variation of each particle was obtained, the approximate distribution of particle quantity at each zone was visualized and the mathematical model of pyrotechnic particle velocity flow field was established.

  2. The atmosphere as particle detector

    NASA Technical Reports Server (NTRS)

    Stanev, Todor

    1990-01-01

    The possibility of using an inflatable, gas-filled balloon as a TeV gamma-ray detector on the moon is considered. By taking an atmosphere of Xenon gas there, or by extracting it on the moon, a layman's detector design is presented. In spite of its shortcomings, the exercise illustrates several of the novel features offered by particle physics on the moon.

  3. Generation of Particles and Seeding

    NASA Technical Reports Server (NTRS)

    Meyers, James F.

    1991-01-01

    One of the most important elements in laser velocimetry, yet the most neglected, is the small particle embedded in the flow field that scatters the light necessary to make velocity measurements. An attempt to remove the confusion in choosing a seeding method by assessing many of the techniques currently used is presented. Their characteristics and typical limitations imposed by various applications are outlined. The ramifications of these methods on measurement accuracy are addressed.

  4. Small-particle-size cement

    SciTech Connect

    Ewert, D.P.; Almond, S.W.; Blerhaus, W.M. II )

    1991-05-01

    Successful remedial cementing has historically been difficult in wells with large-interval, multizone, gravel-packed completions. The reason is the inability of conventional oilfield cements to penetrate gravel packs adequately. Small-particle-size cement (SPSC) was developed to penetrate gravel packs and to provide the zonal isolation required. This paper details the laboratory work, job design, and field implementation of this new cement.

  5. Research in theoretical particle physics

    SciTech Connect

    McKay, D.W.; Munczek, H.; Ralston, J.

    1992-05-01

    This report discusses the following topics in high energy physics: dynamical symmetry breaking and Schwinger-Dyson equation; consistency bound on the minimal model Higgs mass; tests of physics beyond the standard model; particle astrophysics; the interface between perturbative and non-perturbative QCD; cosmology; anisotropy in quantum networks and integer quantum hall behavior; anomalous color transparency; quantum treatment of solitons; color transparency; quantum stabilization of skyrmions; and casimir effect. (LSP)

  6. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1985-01-01

    Research activities in Cosmic Rays Gamma Rays, and Astrophysical Plasmas are covered The investigation of the astrophysical aspects of cosmic rays and gamma rays and of the radiation and electromagnetic field environment of the Earth and other planets are studied. These investigations are carried ut by means of energetic particle and photon detector systems flown on spacecraft and balloons. The emphasis is on precision measurements with high resolution in charge mass and energy. An extensive bibliography is given.

  7. Particle Identification at Belle II

    NASA Astrophysics Data System (ADS)

    Sandilya, S.; Belle Collaboration, II

    2016-11-01

    We report on the charged particle identification (PID) systems for the upcoming Belle II experiment. The time of propagation counter in the central region and the proximity focusing ring imaging Cherenkov counters with aerogel radiator in the forward region will be used as the PID devices. They are expected to provide a kaon identification efficiency of more than 94% at a low pion misidentification probability of 4%. The motivation for the upgrade, method and status of both systems are discussed.

  8. Advances in holographic particle velocimetry

    NASA Astrophysics Data System (ADS)

    Simmons, Scott; Meng, Hui; Hussain, Fazle; Liu, David

    1993-12-01

    Holographic particle velocimetry (HPV) is a promising technique for 3D flow velocity and hence vorticity measurements to study turbulence, coherent structures and vortex interactions. We discuss various aspects in the development of this technique ranging from hologram recording configurations such as in-line, off-axis and multibeam to data processing. Difficulties in implementation are analyzed and solutions are discussed. We also present preliminary measurement results in a 3D vortex flow using one of our prototype HPV systems.

  9. Nozzles for Focusing Aerosol Particles

    DTIC Science & Technology

    2009-10-01

    control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE ( DD -MM-YYYY) October 2009 2. REPORT TYPE Final 3. DATES...Figures Figure 1. The design of the first-generation aerodynamic focusing nozzle for aerosol particles used for SPFS and TAOS instrument prototypes...Some nozzles were fabricated in aluminum and some in steel. It has been used for SPFS and TAOS measurement technologies both in the laboratory and

  10. Particle Suspension Mechanisms - Supplemental Material

    SciTech Connect

    Dillon, M B

    2011-03-03

    This supplemental material provides a brief introduction to particle suspension mechanisms that cause exfoliated skin cells to become and remain airborne. The material presented here provides additional context to the primary manuscript and serves as background for designing possible future studies to assess the impact of skin cells as a source of infectious aerosols. This introduction is not intended to be comprehensive and interested readers are encouraged to consult the references cited.

  11. Photoelectric Charging of Dust Particles

    NASA Technical Reports Server (NTRS)

    Sickafoose, A.; Colwell, J.; Horanyi, M.; Robertson, S.; Walch, B.

    1999-01-01

    Laboratory experiments have been performed on the photoelectric charging of dust particles which are either isolated or adjacent to a surface that is also a photoemitter. We find that zinc dust charges to a positive potential of a few volts when isolated in vacuum and that it charges to a negative potential of a few volts when passed by a photoemitting surface. The illumination is an arc lamp emitting wavelengths longer than 200 nm and the emitting surface is a zirconium foil.

  12. The Multiverse and Particle Physics

    NASA Astrophysics Data System (ADS)

    Donoghue, John F.

    2016-10-01

    The possibility of fundamental theories with very many ground states, each with different physical parameters, changes the way that we approach the major questions of particle physics. Most importantly, it raises the possibility that these different parameters could be realized in different domains in the larger universe. In this review, I survey the motivations for the multiverse and the impact of the idea of the multiverse on the search for new physics beyond the Standard Model.

  13. Solving equations through particle dynamics

    NASA Astrophysics Data System (ADS)

    Edvardsson, S.; Neuman, M.; Edström, P.; Olin, H.

    2015-12-01

    The present work evaluates a recently developed particle method (DFPM). The basic idea behind this method is to utilize a Newtonian system of interacting particles that through dissipation solves mathematical problems. We find that this second order dynamical system results in an algorithm that is among the best methods known. The present work studies large systems of linear equations. Of special interest is the wide eigenvalue spectrum. This case is common as the discretization of the continuous problem becomes dense. The convergence rate of DFPM is shown to be in parity with that of the conjugate gradient method, both analytically and through numerical examples. However, an advantage with DFPM is that it is cheaper per iteration. Another advantage is that it is not restricted to symmetric matrices only, as is the case for the conjugate gradient method. The convergence properties of DFPM are shown to be superior to the closely related approach utilizing only a first order dynamical system, and also to several other iterative methods in numerical linear algebra. The performance properties are understood and optimized by taking advantage of critically damped oscillators in classical mechanics. Just as in the case of the conjugate gradient method, a limitation is that all eigenvalues (spring constants) are required to be of the same sign. DFPM has no other limitation such as matrix structure or a spectral radius as is common among iterative methods. Examples are provided to test the particle algorithm's merits and also various performance comparisons with existent numerical algorithms are provided.

  14. The Galileo Energetic Particles Detector

    NASA Technical Reports Server (NTRS)

    Williams, D. J.; Mcentire, R. W.; Jaskulek, S.; Wilken, B.

    1992-01-01

    Amongst its complement of particles and fields instruments, the Galileo spacecraft carries an Energetic Particles Detector (EPD) designed to measure the characteristics of particle populations important in determining the size, shape, and dynamics of the Jovian magnetosphere. To do this the EPD provides 4pi angular coverage and spectral measurements for Z greater than or equal to 1 ions from 20 keV to 55 MeV, for electrons from 15 keV to greater than 11 MeV, and for the elemental species helium through iron from approximately 10 keV/nucl to 15 MeV/nucl. Two bidirectional telescopes, mounted on a stepping platform, employ magnetic deflection, energy loss versus energy, and time-of-flight techniques to provide 64 rate channels and pulse height analysis of priority selected events. The EPD data system provides a large number of possible operational modes from which a small number will be selected to optimize data collection during the many encounter and cruise phases of the mission. The EPD employs a number of safeing algorithms that are to be used in the event that its self-checking procedures indicate a problem. The instrument and its operation are described.

  15. GPUs in experimental particle physics

    NASA Astrophysics Data System (ADS)

    Berger, Niklaus

    2012-03-01

    Many applications in particle and nuclear physics demand vast computational power with high throughput and low latency. Graphics Processing Units (GPUs) provide such massively parallel floating point computing power at low cost. Indeed many problems are easily parallelized and can be sped up by orders of magnitude by the use of GPUs. The talk will discuss two very different examples, namely the use of GPUs for partial wave analysis and on-line track reconstruction. Partial wave analysis is a key tool in hadron spectroscopy. The unbinned likelihood fits employed are an almost perfect match for the architecture of GPUs. GPU based partial wave analysis was pioneered at the Beijing Spectrometer III experiment in order to deal with world's largest datasets from electron-positron collisions in the charm threshold energy region and is now employed by many groups in the field. The presentation will describe the challenges for implementing a GPU based partial wave analysis and how they were overcome. Usually the most time consuming part of analysing particle physics events is the reconstruction of tracks of charged particles. A new generation of high rate experiments running without a hardware trigger (e.g. the LHCb upgrade, PANDA, a proposed μ->eee search) will be relying on very fast on-line event reconstruction, including tracking. This in turn requires massive amounts of computing power, which is currently best provided by GPUs. The talk will describe the state of GPU based tracking efforts.

  16. Optically powered charged particle accelerator

    NASA Astrophysics Data System (ADS)

    Flesner, Larry D.

    1991-09-01

    A charged particle control apparatus provides very high voltage particle beams. One or more photocell arrays provide bias voltages for beam accelerating stages. The arrays are made from a number of microfabricated photocells connected in series to produce a voltage output that is the sum of the voltages from the individual cells. Arrays of each stage are connected in series to produce a cumulative stage voltage that is applied to an accelerating electrode made part of the stage. Optical power illuminates the stages to generate desired voltage biases to the accelerating electrodes. A light source is used to excite the photocathode when this emission source is used. Electrons from the emission source are accelerated electrodes and are emitted from the chamber which is typically conjoined with other apparatus. By utilizing photocell arrays to generate beam current and accelerating biases, as well as a photocathode for providing a source of electrons, the apparatus of the invention is completely optically isolated thereby requiring no direct electrical connections to the apparatus even though multiple accelerating stages are used to facilitate the achievement of very high voltage particle beams.

  17. Atmospheric discharges and particle fluxes

    NASA Astrophysics Data System (ADS)

    Chilingarian, A.; Chilingaryan, S.; Reymers, A.

    2015-07-01

    Fluxes of the electrons, gamma rays, and neutrons observed by particle detectors located on the Earth's surface during thunderstorms originate so-called Thunderstorm Ground Enhancements (TGEs). The relativistic runaway electron avalanches giving rise to TGEs originate in the thundercloud's lower dipole between the main negatively charged region in the middle of the thundercloud and transient lower positively charged region. Acceleration of electrons in the upper dipole between main negative and main positive charge regions leads to initiation of the terrestrial gamma flashes (TGFs) intensive researched during the last two decades by orbiting gamma ray observatories. TGFs are exceptionally intense, submillisecond bursts of electromagnetic radiation directed to the open space from the thunderstorm atmosphere. Unlike visible lightning, TGF beams do not create a hot plasma channel and optical flash; hence, in the literature they got name "dark lightning." We investigate the TGEs development in 1 min and 1 s time series of particle detector count rates. Synchronized time series of the near-surface electric field and lightning occurrences allows interconnecting two atmospheric phenomena. Registration of the Extensive Air Showers allows approaching problems of relation of the lightning occurrences and particle fluxes.

  18. Engineered plant biomass feedstock particles

    DOEpatents

    Dooley, James H [Federal Way, WA; Lanning, David N [Federal Way, WA; Broderick, Thomas F [Lake Forest Park, WA

    2012-04-17

    A new class of plant biomass feedstock particles characterized by consistent piece size and shape uniformity, high skeletal surface area, and good flow properties. The particles of plant biomass material having fibers aligned in a grain are characterized by a length dimension (L) aligned substantially parallel to the grain and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces. The L.times.W surfaces of particles with L/H dimension ratios of 4:1 or less are further elaborated by surface checking between longitudinally arrayed fibers. The length dimension L is preferably aligned within 30.degree. parallel to the grain, and more preferably within 10.degree. parallel to the grain. The plant biomass material is preferably selected from among wood, agricultural crop residues, plantation grasses, hemp, bagasse, and bamboo.

  19. Anti-Corrosive Powder Particles

    NASA Technical Reports Server (NTRS)

    Parker, Donald; MacDowell, Louis, III

    2005-01-01

    The National Aeronautics and Space Administration (NASA) seeks partners for a new approach in protecting embedded steel surfaces from corrosion. Corrosion of reinforced steel in concrete structures is a significant problem for NASA structures at Kennedy Space Center (KSC) because of the close proximity of the structures to salt spray from the nearby Atlantic Ocean. In an effort to minimize the damage to such structures, coatings were developed that could be applied as liquids to the external surfaces of a substrate in which the metal structures were embedded. The Metallic Pigment Powder Particle technology was developed by NASA at KSC. This technology combines the metallic materials into a uniform particle. The resultant powder can be sprayed simultaneously with a liquid binder onto the surface of concrete structures with a uniform distribution of the metallic pigment for optimum cathodic protection of the underlying steel in the concrete. Metallic Pigment Powder Particle technology improves upon the performance of an earlier NASA technology Liquid Galvanic Coating (U.S. Patent No. 6,627,065).

  20. Pushing particles in extreme fields

    NASA Astrophysics Data System (ADS)

    Gordon, Daniel F.; Hafizi, Bahman; Palastro, John

    2017-03-01

    The update of the particle momentum in an electromagnetic simulation typically employs the Boris scheme, which has the advantage that the magnetic field strictly performs no work on the particle. In an extreme field, however, it is found that onerously small time steps are required to maintain accuracy. One reason for this is that the operator splitting scheme fails. In particular, even if the electric field impulse and magnetic field rotation are computed exactly, a large error remains. The problem can be analyzed for the case of constant, but arbitrarily polarized and independent electric and magnetic fields. The error can be expressed in terms of exponentials of nested commutators of the generators of boosts and rotations. To second order in the field, the Boris scheme causes the error to vanish, but to third order in the field, there is an error that has to be controlled by decreasing the time step. This paper introduces a scheme that avoids this problem entirely, while respecting the property that magnetic fields cannot change the particle energy.

  1. Modeling particle loss in ventilation ducts

    SciTech Connect

    Sippola, Mark R.; Nazaroff, William W.

    2003-04-01

    Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 {micro}m are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.

  2. Characterization of particles from ferrate preoxidation.

    PubMed

    Goodwill, Joseph E; Jiang, Yanjun; Reckhow, David A; Gikonyo, Joseph; Tobiason, John E

    2015-04-21

    Studies were conducted evaluating the nature of particles that result from ferrate reduction in a laboratory water matrix and in a natural surface water with a moderate amount of dissolved organic carbon. Particle characterization included size, surface charge, morphology, X-ray photoelectron spectroscopy, and transmission Fourier transform infrared spectroscopy. Characteristics of ferrate resultant particles were compared to particles formed from dosing ferric chloride, a common water treatment coagulant. In natural water, ferrate addition produced significantly more nanoparticles than ferric addition. These particles had a negative surface charge, resulting in a stable colloidal suspension. In natural and laboratory matrix waters, the ferrate resultant particles had a similar charge versus pH relationship as particles resulting from ferric addition. Particles resulting from ferrate had morphology that differed from particles resulting from ferric iron, with ferrate resultant particles appearing smoother and more granular. X-ray photoelectron spectroscopy results show ferrate resultant particles contained Fe2O3, while ferric resultant particles did not. Results also indicate potential differences in the mechanisms leading to particle formation between ferrate reduction and ferric hydrolysis.

  3. Particle Transport in Parallel-Plate Reactors

    SciTech Connect

    Rader, D.J.; Geller, A.S.

    1999-08-01

    A major cause of semiconductor yield degradation is contaminant particles that deposit on wafers while they reside in processing tools during integrated circuit manufacturing. This report presents numerical models for assessing particle transport and deposition in a parallel-plate geometry characteristic of a wide range of single-wafer processing tools: uniform downward flow exiting a perforated-plate showerhead separated by a gap from a circular wafer resting on a parallel susceptor. Particles are assumed to originate either upstream of the showerhead or from a specified position between the plates. The physical mechanisms controlling particle deposition and transport (inertia, diffusion, fluid drag, and external forces) are reviewed, with an emphasis on conditions encountered in semiconductor process tools (i.e., sub-atmospheric pressures and submicron particles). Isothermal flow is assumed, although small temperature differences are allowed to drive particle thermophoresis. Numerical solutions of the flow field are presented which agree with an analytic, creeping-flow expression for Re < 4. Deposition is quantified by use of a particle collection efficiency, which is defined as the fraction of particles in the reactor that deposit on the wafer. Analytic expressions for collection efficiency are presented for the limiting case where external forces control deposition (i.e., neglecting particle diffusion and inertia). Deposition from simultaneous particle diffusion and external forces is analyzed by an Eulerian formulation; for creeping flow and particles released from a planar trap, the analysis yields an analytic, integral expression for particle deposition based on process and particle properties. Deposition from simultaneous particle inertia and external forces is analyzed by a Lagrangian formulation, which can describe inertia-enhanced deposition resulting from particle acceleration in the showerhead. An approximate analytic expression is derived for particle

  4. New mass measurement method of aerosol particle using vibrating probe particle controlled by radiation pressure

    NASA Astrophysics Data System (ADS)

    Hariyama, Tatsuo; Takaya, Yasuhiro; Miyoshi, Takashi

    2005-11-01

    Aerosol particles with sub-micro meter size inhaled into respiratory systems cause serious damage to human body. In order to evaluate the health effects of the particles, classification methods of the particles with size and mass are needed. Several measurement methods of the particle size are established. However, conventional mass measurement methods are not enough to measure the particles with sub- pico gram. We propose a new mass measurement method of the aerosol particles based on laser trapping. In this method, an optically trapped silica particle is used as a measuring probe particle. The probe particle is trapped at a beam waist of the focused laser light and is forced to vibrate by deflecting the beam waist using AOD. The vibrating probe particle has a resonance frequency because it is governed by the spring-mass-damper system. When an aerosol particle is attached to the probe particle, the resonance frequency shifts according to the increase of the total mass. The mass of the aerosol particle can be measured from the shift of the resonance frequency. Experimentally, it is confirmed that the probe particle is governed by the spring-mass-damper system and has a resonance frequency. When a silica fine particle of 3pg in mass used as an aerosol particle is attached to the probe particle, the resonance frequency shift occurs as expected in the dynamic system and the fine particle mass can be measured based on the proposed method.

  5. Personal exposure to ultrafine particles.

    PubMed

    Wallace, Lance; Ott, Wayne

    2011-01-01

    Personal exposure to ultrafine particles (UFP) can occur while people are cooking, driving, smoking, operating small appliances such as hair dryers, or eating out in restaurants. These exposures can often be higher than outdoor concentrations. For 3 years, portable monitors were employed in homes, cars, and restaurants. More than 300 measurement periods in several homes were documented, along with 25 h of driving two cars, and 22 visits to restaurants. Cooking on gas or electric stoves and electric toaster ovens was a major source of UFP, with peak personal exposures often exceeding 100,000 particles/cm³ and estimated emission rates in the neighborhood of 10¹² particles/min. Other common sources of high UFP exposures were cigarettes, a vented gas clothes dryer, an air popcorn popper, candles, an electric mixer, a toaster, a hair dryer, a curling iron, and a steam iron. Relatively low indoor UFP emissions were noted for a fireplace, several space heaters, and a laser printer. Driving resulted in moderate exposures averaging about 30,000 particles/cm³ in each of two cars driven on 17 trips on major highways on the East and West Coasts. Most of the restaurants visited maintained consistently high levels of 50,000-200,000 particles/cm³ for the entire length of the meal. The indoor/outdoor ratios of size-resolved UFP were much lower than for PM₂.₅ or PM₁₀, suggesting that outdoor UFP have difficulty in penetrating a home. This in turn implies that outdoor concentrations of UFP have only a moderate effect on personal exposures if indoor sources are present. A time-weighted scenario suggests that for typical suburban nonsmoker lifestyles, indoor sources provide about 47% and outdoor sources about 36% of total daily UFP exposure and in-vehicle exposures add the remainder (17%). However, the effect of one smoker in the home results in an overwhelming increase in the importance of indoor sources (77% of the total).

  6. Scalar fields and particle accelerators

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph; Bose, Benjamin

    2015-06-01

    The phenomenon discovered in 2009 by Bañados, Silk and West where particle collisions can achieve arbitrary high center-of-mass (c.m.) energies close to the event horizon of an extreme Kerr black hole, has generated a lot of interest. Although rotation seemed to be an essential requirement, it was later shown that arbitrary high energies can also be achieved for collisions between radially moving particles near the horizon of the electrically charged extreme Reissner-Nordström black hole. Recently Patil and Joshi claimed that instead of spinning up the black hole one can also crank up the c.m. energy of particle collisions by "charging up" a static black hole with a massless scalar field. In this regard they showed that infinite energies can be attained in the vicinity of the naked singularity of the Janis-Newman-Wincour (JNW) spacetime, which contains a massless scalar field that also becomes infinite at the position of the curvature singularity. In this study we show that Patil and Joshi's claim does not apply for other static black hole systems endowed with a massless scalar field. In particular we consider the well-known Bekenstein black hole and the recently discovered Martínez-Troncoso-Zanelli black hole, and show that the expression of the c.m. energy for particle collisions near the event horizons of these black holes is no different than the corresponding case with vanishing scalar field represented by the Schwarzschild solution. Moreover by studying the motion of scalar test charges that interact with the background scalar field in these black hole spacetimes we show that the resulting c.m. energies are even smaller than in the case of free particles. This shows that the infinite energies obtained by Patil and Joshi may not be due to the fact that the black hole contains a massless scalar field, but may be instead related to the geometry of the naked singularity in the JNW spacetime. An analogous case of infinite c.m. energy in the vicinity of a naked

  7. Effective Forces Between Colloidal Particles

    NASA Technical Reports Server (NTRS)

    Tehver, Riina; Banavar, Jayanth R.; Koplik, Joel

    1999-01-01

    Colloidal suspensions have proven to be excellent model systems for the study of condensed matter and its phase behavior. Many of the properties of colloidal suspensions can be investigated with a systematic variation of the characteristics of the systems and, in addition, the energy, length and time scales associated with them allow for experimental probing of otherwise inaccessible regimes. The latter property also makes colloidal systems vulnerable to external influences such as gravity. Experiments performed in micro-ravity by Chaikin and Russell have been invaluable in extracting the true behavior of the systems without an external field. Weitz and Pusey intend to use mixtures of colloidal particles with additives such as polymers to induce aggregation and form weak, tenuous, highly disordered fractal structures that would be stable in the absence of gravitational forces. When dispersed in a polarizable medium, colloidal particles can ionize, emitting counterions into the solution. The standard interaction potential in these charged colloidal suspensions was first obtained by Derjaguin, Landau, Verwey and Overbeek. The DLVO potential is obtained in the mean-field linearized Poisson-Boltzmann approximation and thus has limited applicability. For more precise calculations, we have used ab initio density functional theory. In our model, colloidal particles are charged hard spheres, the counterions are described by a continuum density field and the solvent is treated as a homogeneous medium with a specified dielectric constant. We calculate the effective forces between charged colloidal particles by integrating over the solvent and counterion degrees of freedom, taking into account the direct interactions between the particles as well as particle-counterion, counterion-counterion Coulomb, counterion entropic and correlation contributions. We obtain the effective interaction potential between charged colloidal particles in different configurations. We evaluate two

  8. Charged particles in Titan's ionosphere

    NASA Astrophysics Data System (ADS)

    Tripathi, Sachchida

    2010-05-01

    Charged particles in Titan's ionosphere Marykutty Michael1, Sachchida Nand Tripathi1,2,3, Pratima Arya1 1Indian Institute of Technology Kanpur 2Oak Ridge Associated Universities 3NASA Goddard Space Flight Center Observations by two instruments onboard the Cassini spacecraft, Ion Neutral Mass Spectrometer (INMS) and CAssini Plasma Spectrometer (CAPS), revealed the existence of heavy hydrocarbon and nitrile species with masses of several thousand atomic mass units at altitudes of 950 - 1400 km in the atmosphere of Titan (Waite et al., 2007; Crary et al., 2009). Though these particles were believed to be molecules, they are most likely aerosols formed by the clumping of smaller molecules (Waite et al., 2009). These particles were estimated to have a density of 10-3 kg m-3 and a size of up to 256 nm. The existence of very heavy ions has also been observed by the CAPS components with a mass by charge ratio of up to 10000 (Coates et al., 2007, 2009; Sittler et al., 2009). The goal of this paper is to find out whether the so called heavy ions (or charged particles) are generated by the charge transfer of ions and electrons to the particles. The charging of these particles has been studied by using the charge balance equations that include positive ions, negative ions, electrons, neutral and charged particles. Information on the most abundant ion clusters are obtained from Vuitton et al., (2009) and Wilson and Atreya, (2004). Mass by charge ratio thus calculated will be compared with those observed by Coates et al. (2007). References: Coates AJ, et al., Discovery of heavy negative ions in Titan's ionosphere, Geophys. Res. Lett., 34:L22103, 2007. Coates AJ, et al., Heavy negative ions in titan's ionosphere: altitude and latitude dependence. Planet. Space Sci., doi:10.1016/j.pss.2009.05.009, 2009. Crary F.J., et al., Heavy ions, temperatures and winds in titan's ionosphere: Combined cassini caps and inms observations. Planet. Space Sci., doi:10.1016/j.pss.2009.09.006, 2009

  9. Particles, Quarks, Leptons and Coloured Glue.

    ERIC Educational Resources Information Center

    Ryder, Lewis

    1980-01-01

    Explains the current situation in particle physics by reviewing the three major periods in the development of atomic theory. Outlines the current picture of fundamental particles and identifies five major problems with this model. (GS)

  10. Diesel exhaust particles and airway inflammation

    EPA Science Inventory

    Purpose of review. Epidemiologic investigation has associated traffic-related air pollution with adverse human health outcomes. The capacity ofdiesel exhaust particles (DEP), a major emission source air pollution particle, to initiate an airway inflammation has subsequently been ...

  11. Air pollution particles and iron homeostasis

    EPA Science Inventory

    Background: The mechanism underlying biological effects of particles deposited in the lung has not been defined. Major Conclusions: A disruption in iron homeostasis follows exposure of cells to all particulate matter including air pollution particles. Following endocytosis, fun...

  12. Particle-impact noise detector (PIND)

    NASA Technical Reports Server (NTRS)

    Barr, R. J.; Jackson, D. E.; Leaf, W. D.; Meza, R. G.; Rader, G. E.

    1978-01-01

    Package, in page assembly, is subjected to low-frequency vibration, and noise generated by particle impacts is picked up by transducer. Test procedure calls for three transverse shocks to be applied to page to dislodge any trapped particles.

  13. Shape evolution of a melting nonspherical particle.

    PubMed

    Kintea, Daniel M; Hauk, Tobias; Roisman, Ilia V; Tropea, Cameron

    2015-09-01

    In this study melting of irregular ice crystals was observed in an acoustic levitator. The evolution of the particle shape is captured using a high-speed video system. Several typical phenomena have been discovered: change of the particle shape, appearance of a capillary flow of the melted liquid on the particle surface leading to liquid collection at the particle midsection (where the interface curvature is smallest), and appearance of sharp cusps at the particle tips. No such phenomena can be observed during melting of spherical particles. An approximate theoretical model is developed which accounts for the main physical phenomena associated with melting of an irregular particle. The agreement between the theoretical predictions for the melting time, for the evolution of the particle shape, and the corresponding experimental data is rather good.

  14. Article coated with flash bonded superhydrophobic particles

    DOEpatents

    Simpson, John T [Clinton, TN; Blue, Craig A [Knoxville, TN; Kiggans, Jr., James O [Oak Ridge, TN

    2010-07-13

    A method of making article having a superhydrophobic surface includes: providing a solid body defining at least one surface; applying to the surface a plurality of diatomaceous earth particles and/or particles characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m, the particles being further characterized by a plurality of nanopores, wherein at least some of the nanopores provide flow through porosity, the particles being further characterized by a plurality of spaced apart nanostructured features that include a contiguous, protrusive material; flash bonding the particles to the surface so that the particles are adherently bonded to the surface; and applying a hydrophobic coating layer to the surface and the particles so that the hydrophobic coating layer conforms to the nanostructured features.

  15. Ordered transport and identification of particles

    DOEpatents

    Shera, E.B.

    1993-05-11

    A method and apparatus are provided for application of electrical field gradients to induce particle velocities to enable particle sequence and identification information to be obtained. Particle sequence is maintained by providing electroosmotic flow for an electrolytic solution in a particle transport tube. The transport tube and electrolytic solution are selected to provide an electroosmotic radius of >100 so that a plug flow profile is obtained for the electrolytic solution in the transport tube. Thus, particles are maintained in the same order in which they are introduced in the transport tube. When the particles also have known electrophoretic velocities, the field gradients introduce an electrophoretic velocity component onto the electroosmotic velocity. The time that the particles pass selected locations along the transport tube may then be detected and the electrophoretic velocity component calculated for particle identification. One particular application is the ordered transport and identification of labeled nucleotides sequentially cleaved from a strand of DNA.

  16. Final Report: Particle Physics Research Program

    SciTech Connect

    Karchin, Paul E.

    2011-09-01

    We describe recent progress in accelerator-based experiments in high-energy particle physics and progress in theoretical investigations in particle physics. We also describe future plans in these areas.

  17. Ring particles - Collisional interactions and physical nature

    NASA Technical Reports Server (NTRS)

    Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R.; Greenberg, R.

    1984-01-01

    Attention is given to the properties of, and dynamical processes affecting individual particles of Saturn's rings. Because particles tend to be gravitationally bound when located on the surfaces of larger particles, and since net tidal stresses within the particles are small, particle collisions should produce accretion in Saturn's rings. Rapid accretionary processes within the rings are counterbalanced by tidal disruption of the larger accreted aggregates, which are presently designated 'dynamic ephemeral bodies'. The coefficient of restitution is probably very low, implying that the large particles containing most of the rings' mass are in a monolayer, although the small particles responsible for most of the rings' visible cross section form a layer many particles thick. Kinematic viscosity and interparticle erosive process models should incorporate these properties.

  18. A research Program in Elementary Particle Physics

    SciTech Connect

    Sobel, Henry; Molzon, William; Lankford, Andrew; Taffard, Anyes; Whiteson, Daniel; Kirkby, David

    2013-07-25

    Work is reported in: Neutrino Physics, Cosmic Rays and Elementary Particles; Particle Physics and Charged Lepton Flavor Violation; Research in Collider Physics; Dark Energy Studies with BOSS and LSST.

  19. Shape evolution of a melting nonspherical particle

    NASA Astrophysics Data System (ADS)

    Kintea, Daniel M.; Hauk, Tobias; Roisman, Ilia V.; Tropea, Cameron

    2015-09-01

    In this study melting of irregular ice crystals was observed in an acoustic levitator. The evolution of the particle shape is captured using a high-speed video system. Several typical phenomena have been discovered: change of the particle shape, appearance of a capillary flow of the melted liquid on the particle surface leading to liquid collection at the particle midsection (where the interface curvature is smallest), and appearance of sharp cusps at the particle tips. No such phenomena can be observed during melting of spherical particles. An approximate theoretical model is developed which accounts for the main physical phenomena associated with melting of an irregular particle. The agreement between the theoretical predictions for the melting time, for the evolution of the particle shape, and the corresponding experimental data is rather good.

  20. Heavy particle radiotherapy: prospects and pitfalls

    SciTech Connect

    Faju, M.R.

    1980-01-01

    The use of heavy particles in radiotherapy of tumor volumes is examined. Particles considered are protons, helium ions, heavy ions, negative pions, and fast neutrons. Advantages and disadvantages are discussed. (ACR)

  1. Ordered transport and identification of particles

    DOEpatents

    Shera, E. Brooks

    1993-01-01

    A method and apparatus are provided for application of electrical field gradients to induce particle velocities to enable particle sequence and identification information to be obtained. Particle sequence is maintained by providing electroosmotic flow for an electrolytic solution in a particle transport tube. The transport tube and electrolytic solution are selected to provide an electroosmotic radius of >100 so that a plug flow profile is obtained for the electrolytic solution in the transport tube. Thus, particles are maintained in the same order in which they are introduced in the transport tube. When the particles also have known electrophoretic velocities, the field gradients introduce an electrophoretic velocity component onto the electroosmotic velocity. The time that the particles pass selected locations along the transport tube may then be detected and the electrophoretic velocity component calculated for particle identification. One particular application is the ordered transport and identification of labeled nucleotides sequentially cleaved from a strand of DNA.

  2. Pharmaceutical Particle Engineering via Spray Drying

    PubMed Central

    2007-01-01

    This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theoretical framework for particle design calculations. It reviews experimental research into parameters that influence particle formation. A classification based on dimensionless numbers is presented that can be used to estimate how excipient properties in combination with process parameters influence the morphology of the engineered particles. A wide range of pharmaceutical application examples—low density particles, composite particles, microencapsulation, and glass stabilization—is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts. PMID:18040761

  3. Emperor's new clothes: Is particle disease really infected particle disease?

    PubMed

    Wasko, Marcin K; Goodman, Stuart B

    2016-09-01

    Aseptic loosening remains the most significant long-term complication of total hip replacement. The current paradigm points to an inflammatory response to wear particles as its main trigger. Recently, there have been increasing numbers of positive bacterial isolates reported among patients with clinically absent infection. This paper reviews existing evidence on possible involvement of bacteria and microbial-associated molecular patterns in the pathology of so-called "aseptic loosening." © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1497-1504, 2016.

  4. Current experiments in particle physics - particle data group

    SciTech Connect

    Galic, H.; Lehar, F.; Kettle, P.R.

    1996-09-01

    This report contains summaries of current and recent experiments in Particle Physics. Included are experiments at BEPC (Beijing), BNL, CEBAF, CERN, CESR, DESY, FNAL, Frascati, ITEP (Moscow), JINR (Dubna), KEK, LAMPF, Novosibirsk, PNPI (St. Petersburg), PSI, Saclay, Serpukhov, SLAC, and TRIUMF, and also several proton decay and solar neutrino experiments. Excluded are experiments that finished taking data before 1991. Instructions are given for the World Wide Web (WWW) searching of the computer database (maintained under the SLAC-SPIRES system) that contains the summaries.

  5. Determination of Origin of NASA Stratospheric Particles

    NASA Astrophysics Data System (ADS)

    Kapišinský, I.; Figusch, V.; Hajduk, A.; Ivan, J.; Iždinský, K.

    1996-04-01

    Paper presents a reanalysis of four stratospheric particles registered in the Cosmic Dust Catalogs (CDC). Two particles have been classifed in the NASA Johnson Space Centre (JSC) in Houston as natural, terrestrial contaminants and the origin of the other two particles was found questionable, probably cosmic. Present study has confirmed these conclusions; however some new additional features in the chemical analysis have been found which can finally determine the classification of the particles with unclear origin.

  6. Algorithm for Computing Particle/Surface Interactions

    NASA Technical Reports Server (NTRS)

    Hughes, David W.

    2009-01-01

    An algorithm has been devised for predicting the behaviors of sparsely spatially distributed particles impinging on a solid surface in a rarefied atmosphere. Under the stated conditions, prior particle-transport models in which (1) dense distributions of particles are treated as continuum fluids; or (2) sparse distributions of particles are considered to be suspended in and to diffuse through fluid streams are not valid.

  7. Solid Hydrogen Particles Analyzed for Atomic Fuels

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2001-01-01

    Solid hydrogen particles have been selected as a means of storing atomic propellants in future launch vehicles (refs. 1 to 2). In preparation for this, hydrogen particle formation in liquid helium was tested experimentally. These experiments were conducted to visually characterize the particles and to observe their formation and molecular transformations (aging) while in liquid helium. The particle sizes, molecular transformations, and agglomeration times were estimated from video image analyses. The experiments were conducted at the NASA Glenn Research Center in the Supplemental Multilayer Insulation Research Facility (SMIRF, ref. 3). The facility has a vacuum tank, into which the experimental setup was placed. The vacuum tank prevented heat leaks and subsequent boiloff of the liquid helium, and the supporting systems maintained the temperature and pressure of the liquid helium bath where the solid particles were created. As the operation of the apparatus was developed, the hydrogen particles were easily visualized. The figures (ref. 1) show images from the experimental runs. The first image shows the initial particle freezing, and the second image shows the particles after the small particles have agglomerated. The particles finally all clump, but stick together loosely. The solid particles tended to agglomerate within a maximum of 11 min, and the agglomerate was very weak. Because the hydrogen particles are buoyant in the helium, the agglomerate tends to compact itself into a flat pancake on the surface of the helium. This pancake agglomerate is easily broken apart by reducing the pressure above the liquid. The weak agglomerate implies that the particles can be used as a gelling agent for the liquid helium, as well as a storage medium for atomic boron, carbon, or hydrogen. The smallest particle sizes that resulted from the initial freezing experiments were about 1.8 mm. About 50 percent of the particles formed were between 1.8 to 4.6 mm in diameter. These very

  8. Yukawa particles in a confining potential

    SciTech Connect

    Girotto, Matheus Levin, Yan; Santos, Alexandre P. dos; Colla, Thiago

    2014-07-07

    We study the density distribution of repulsive Yukawa particles confined by an external potential. In the weak coupling limit, we show that the mean-field theory is able to accurately account for the particle distribution. In the strong coupling limit, the correlations between the particles become important and the mean-field theory fails. For strongly correlated systems, we construct a density functional theory which provides an excellent description of the particle distribution, without any adjustable parameters.

  9. On the modification of particle dispersion in isotropic turbulence by free rotation of particle

    NASA Astrophysics Data System (ADS)

    Park, Yongnam; Lee, Changhoon

    2008-11-01

    Effect of a particle's spin is investigated numerically by considering the effect of lift occurring due to difference of rotations of a particle and of fluid such as the Saffman lift and Magnus force. These lift forces have been neglected in many previous works on particle-laden turbulence. The trajectory of particles can be changed by the lift forces, resulting in significant modification of the stochastic characteristics of heavy particles. Probability density functions and autocorrelations are examined of velocity, acceleration of solid particle and acceleration of fluid at the position of solid particle. Changes in velocity statistics are negligible but statistics related with acceleration are a little bit changed by particle's rotation. When a laden particle encounters with coherent structures during the motion, the particle's rotation might significantly affects the motion due to intermittently large fluid acceleration near coherent structures. The result can be used for development of stochastic model for particle dispersion. Detailed physical interpretation will be presented in the meeting.

  10. Implementing Molecular Dynamics on Hybrid High Performance Computers - Particle-Particle Particle-Mesh

    SciTech Connect

    Brown, W Michael; Kohlmeyer, Axel; Plimpton, Steven J; Tharrington, Arnold N

    2012-01-01

    The use of accelerators such as graphics processing units (GPUs) has become popular in scientific computing applications due to their low cost, impressive floating-point capabilities, high memory bandwidth, and low electrical power requirements. Hybrid high-performance computers, machines with nodes containing more than one type of floating-point processor (e.g. CPU and GPU), are now becoming more prevalent due to these advantages. In this paper, we present a continuation of previous work implementing algorithms for using accelerators into the LAMMPS molecular dynamics software for distributed memory parallel hybrid machines. In our previous work, we focused on acceleration for short-range models with an approach intended to harness the processing power of both the accelerator and (multi-core) CPUs. To augment the existing implementations, we present an efficient implementation of long-range electrostatic force calculation for molecular dynamics. Specifically, we present an implementation of the particle-particle particle-mesh method based on the work by Harvey and De Fabritiis. We present benchmark results on the Keeneland InfiniBand GPU cluster. We provide a performance comparison of the same kernels compiled with both CUDA and OpenCL. We discuss limitations to parallel efficiency and future directions for improving performance on hybrid or heterogeneous computers.

  11. Quantitative organic vapor-particle sampler

    DOEpatents

    Gundel, Lara; Daisey, Joan M.; Stevens, Robert K.

    1998-01-01

    A quantitative organic vapor-particle sampler for sampling semi-volatile organic gases and particulate components. A semi-volatile organic reversible gas sorbent macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 .mu.m for use in an integrated diffusion vapor-particle sampler.

  12. New particle searches at Tevatron (II)

    SciTech Connect

    Kamon, T.; CDF and D0 Collaborations

    1996-05-01

    Various recent results of new particle searches at the Fermilab Tevatron are presented. No evidence is found for supersymmetric particles (chargino, gluino), leptoquark bosons and heavy gauge bosons in {ital p{anti P}} collisions at {radical}s = 1.8 TeV. Excluded mass regions for each particle are determined.

  13. Fluidized bed feeding of carbon black particles

    SciTech Connect

    Rybak, W.; Lahaye, J.

    1995-11-01

    Experiments on ignition and combustion of solid fuels and flow measurements (laser doppler velocimetry) require a pulverized fuel or refractory particle powder delivery system. Usually in any experiments involving the study of coal/or carbon and metals combustion, the fuel delivery system supplies particles to an entrained flow furnace or to an open gas flame. The particle feed system is a critical element of the apparatus; the accuracy and reliability of the data obtained form the experiments depend greatly on the system`s capacity to provide a wide range of stable and accurately measured mass flow-rates for different particle sizes over a desired period of time. In this study on combustion kinetics of carbon black particles under pressure, the particles are introduced from a feed system in a dilute, single stream on the center line of the reactor and burned downstream of a variety of premixed flames. The particle feed system is a vital component; its design must be matched to the particle size (below 0.1 micron), particle loading and flow rates required to maintain a uniform and continuous suspension without particle agglomeration, so that a stable particle combustion plume can be obtained. The present work describes a new feeder system capable of delivering small particles (like carbon black) over a wide range of flow-rates at high pressure.

  14. Optically active biological particle distinguishing apparatus

    DOEpatents

    Salzman, Gary C.; Kupperman, Robert H.

    1989-01-01

    The disclosure is directed to organic particle sorting and identification. High frequency pulses of circularly polarized light, alternating between left and right, intersect a fast moving stream of organic particles. Circular intensity differential scattering and linear intensity differential scattering are monitored to uniquely identify a variety of organic particles.

  15. The dialogue between particle physics and cosmology

    SciTech Connect

    Sadoulet, B.

    1988-04-01

    In the last decade, a very close relationship has developed between particle physics and cosmology. The purpose of these lectures is to introduce particle physicists to the many scientific connections between the two fields. Before entering into the discussion of specific topics, it will first be shown that particle physics and cosmology are completely interdependent. 173 refs., 35 figs., 5 tabs.

  16. Three-Dimensional Visualization of Particle Tracks.

    ERIC Educational Resources Information Center

    Julian, Glenn M.

    1993-01-01

    Suggests ways to bring home to the introductory physics student some of the excitement of recent discoveries in particle physics. Describes particle detectors and encourages the use of the Standard Model along with real images of particle tracks to determine three-dimensional views of tracks. (MVL)

  17. Resource Letter PD-1 on Particle Detectors

    ERIC Educational Resources Information Center

    Trower, W. Peter

    1970-01-01

    Intended to guide college physicists to literature on nuclear and sub-nuclear particle detectors. The paper contains a discussion of (1) interactions of particles with matter and (2) individual particle detectors, each section being followed by an annotated bibliography of selected reference materials. Rankings are given to the articles on the…

  18. Swedish Modal Particles in a Contrastive Perspective.

    ERIC Educational Resources Information Center

    Aijmer, Karen

    1996-01-01

    Presents a study based on the analysis of contrastive Swedish-English data on modal particles. The article maintains that the meaning of modal particles requires an analysis of their pragmatic aspects such as the relation between the interlocutors. The analysis most accurately accounting for the multifunctionality of the particles is based on a…

  19. Digital Holographic Interferometry for Airborne Particle Characterization

    DTIC Science & Technology

    2015-03-19

    hologram and its extinction cross section, and a computational demonstration that holographic interferometry can resolve aerosol particle size ...holographic interferometry can resolve aerosol particle size evolution. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of...Characterization of Atmospheric Aerosols workshop, Smolenice, Slovak Republic (2013). 7. Poster : Digital Holographic Imaging of Aerosol Particles In-Flight

  20. Recent trends in particle size analysis techniques

    NASA Technical Reports Server (NTRS)

    Kang, S. H.

    1984-01-01

    Recent advances and developments in the particle-sizing technologies are briefly reviewed in accordance with three operating principles including particle size and shape descriptions. Significant trends of the particle size analysing equipment recently developed show that compact electronic circuitry and rapid data processing systems were mainly adopted in the instrument design. Some newly developed techniques characterizing the particulate system were also introduced.

  1. Teaching Elementary Particle Physics, Part II

    ERIC Educational Resources Information Center

    Hobson, Art

    2011-01-01

    In order to explain certain features of radioactive beta decay, Wolfgang Pauli suggested in 1930 that the nucleus emitted, in addition to a beta particle, another particle of an entirely new type. The hypothesized particle, dubbed the neutrino, would not be discovered experimentally for another 25 years. It's not easy to detect neutrinos, because…

  2. Interplanetary dust particles and impact erosion

    NASA Astrophysics Data System (ADS)

    Klacka, J.; Saniga, M.

    1992-11-01

    Consideration is given to the motion of interplanetary dust particles under the effect of collisions with much smaller interplanetary dust particles. The equation of motion is derived. Perturbation equations of celestial mechanics are also discussed. The results are compared with the Poynting-Robertson effect and the effect of solar wind on the motion of the interplanetary dust particles.

  3. Saha equation, single and two particle states

    NASA Technical Reports Server (NTRS)

    Kraeft, W. D.; Girardeau, M. D.; Strege, B.

    1990-01-01

    Single- and two-particle properties in a dense plasma are discussed in connection with their role in the mass action law for a partially ionized plasma. The two-particle-bound states are nearly density independent, while the continuum is essentially shifted. The single-particle states are damped, and their energy has a negative shift and a parabolic behavior for small momenta.

  4. Electroless plating apparatus for discrete microsized particles

    DOEpatents

    Mayer, Anton

    1978-01-01

    Method and apparatus are disclosed for producing very uniform coatings of a desired material on discrete microsized particles by electroless techniques. Agglomeration or bridging of the particles during the deposition process is prevented by imparting a sufficiently random motion to the particles that they are not in contact with each other for a time sufficient for such to occur.

  5. Tumbling in Turbulence: How much does particle shape effect particle motion?

    NASA Astrophysics Data System (ADS)

    Variano, E. A.; Andersson, H. I.; Zhao, L.; Byron, M.

    2014-12-01

    Natural particles suspended in surface water are often non-spherical. We explore the ways in which particle shape effects particle motion, focusing specifically on how particle rotation is divided into spinning and tumbling components. This, in turn, will effect particle collision, clustering, and settling rates. We focus on idealized axisymmetric particles shaped as rods, discs, and spheroids. They are chosen so as to explain the physics of aspherical-particle motion that will be relevant for natural particles such as plankton, sediment, or aggregates (e.g. oil-mineral aggregates, clay flocs, or bio-sediment aggregates held together by TEP). Our work begins with laboratory measurements of particle motion in a turbulence tank built to mimic the flow found in rivers, estuaries, and the ocean surface mixed layer. We then proceed to direct numerical simulation of particle-flow interactions in sheared turbulence similar to that which is found in the surface water of creeks and rivers. We find that shape has only a very weak effect on particle angular velocity, which is a quantity calculated with respect the global reference frame (i.e. east/north/up). If we analyze rotation in a particle's local frame (i.e. the particle's principle axes of rotation), then particle shape has a strong effect on rotation. In the local frame, rotation is described by two components: tumbling and spinning. We find that rod-shaped particles spin more than they tumble, and we find that disc-shaped particles tumble more than they spin. Such behavior is indicative of how particles respond the the directional influence of vortex tubes in turbulence, and such response has implications for particle motion other than rotation. Understanding particle alignment is relevant for predicting particle-particle collision rates, particle-wall collision rates, and the shear-driven breakup of aggregates. We discuss these briefly in the context of what can be concluded from the rotation data discussed above.

  6. PDT - PARTICLE DISPLACEMENT TRACKING SOFTWARE

    NASA Technical Reports Server (NTRS)

    Wernet, M. P.

    1994-01-01

    Particle Imaging Velocimetry (PIV) is a quantitative velocity measurement technique for measuring instantaneous planar cross sections of a flow field. The technique offers very high precision (1%) directionally resolved velocity vector estimates, but its use has been limited by high equipment costs and complexity of operation. Particle Displacement Tracking (PDT) is an all-electronic PIV data acquisition and reduction procedure which is simple, fast, and easily implemented. The procedure uses a low power, continuous wave laser and a Charged Coupled Device (CCD) camera to electronically record the particle images. A frame grabber board in a PC is used for data acquisition and reduction processing. PDT eliminates the need for photographic processing, system costs are moderately low, and reduced data are available within seconds of acquisition. The technique results in velocity estimate accuracies on the order of 5%. The software is fully menu-driven from the acquisition to the reduction and analysis of the data. Options are available to acquire a single image or 5- or 25-field series of images separated in time by multiples of 1/60 second. The user may process each image, specifying its boundaries to remove unwanted glare from the periphery and adjusting its background level to clearly resolve the particle images. Data reduction routines determine the particle image centroids and create time history files. PDT then identifies the velocity vectors which describe the particle movement in the flow field. Graphical data analysis routines are included which allow the user to graph the time history files and display the velocity vector maps, interpolated velocity vector grids, iso-velocity vector contours, and flow streamlines. The PDT data processing software is written in FORTRAN 77 and the data acquisition routine is written in C-Language for 80386-based IBM PC compatibles running MS-DOS v3.0 or higher. Machine requirements include 4 MB RAM (3 MB Extended), a single or

  7. Horns as particle velocity amplifiers.

    PubMed

    Donskoy, Dimitri M; Cray, Benjamin A

    2011-11-01

    Preliminary measurements and numerical predictions reveal that simple, and relatively small, horns generate remarkable amplification of acoustic particle velocity. For example, below 2 kHz, a 2.5 cm conical horn has a uniform velocity amplification ratio (throat-to-mouth) factor of approximately 3, or, in terms of a decibel level, 9.5 dB. It is shown that the velocity amplification factor depends on the horn's mouth-to-throat ratio as well as, though to a lesser degree, the horn's flare rate. A double horn configuration provides limited additional gain, approximately an increase of up to 25%.

  8. Gated charged-particle trap

    DOEpatents

    Benner, W. Henry

    1999-01-01

    The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector.

  9. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1987-01-01

    Discussed are the research activities in Cosmic Rays, Gamma Rays, and Astrophysical Plasmas supported under NASA Grant NGR 05-002-160. The report is divided into sections which describe the activities, followed by a bibliography. This research program is directed toward the investigation of the astrophysical aspects of cosmic rays and gamma rays and of the radiation and electromagnetic field environment of the Earth and other planets. These investigations are carried out by means of energetic particle and photon detector systems flown on spacecraft and balloons.

  10. Particles, Fields, and Gravitation. Proceedings

    SciTech Connect

    Rembieli ski, J.

    1998-11-01

    These proceedings represent papers presented at the Conference on Particles, Fields, and Gravitation held in Lodz, Poland in April, 1998. The topics discussed included quantum deformations and noncommutative geometry, quantum mechanics, quantum and topological field theory, modern gravitation theory and geometrical methods in physics. Solvable and quasisolvable models were also disussed. The talks and the resulting papers provided a comprehensive coverage of the main aspects of contemporary theoretical and mathematical physics. The Conference was attended by more than 100 scientists from all over the world. There were 54 papers presented at the conference,out of which 1 paper has been abstracted for the Energy,Science and Technology database.(AIP)

  11. Particles, Cutoffs and Inequivalent Representations

    NASA Astrophysics Data System (ADS)

    Egg, Matthias; Lam, Vincent; Oldofredi, Andrea

    2017-03-01

    We critically review the recent debate between Doreen Fraser and David Wallace on the interpretation of quantum field theory, with the aim of identifying where the core of the disagreement lies. We show that, despite appearances, their conflict does not concern the existence of particles or the occurrence of unitarily inequivalent representations. Instead, the dispute ultimately turns on the very definition of what a quantum field theory is. We further illustrate the fundamental differences between the two approaches by comparing them both to the Bohmian program in quantum field theory.

  12. Photobiomolecular metallic particles and films

    DOEpatents

    Hu, Zhong-Cheng

    2003-05-06

    The method of the invention is based on the unique electron-carrying function of a photocatalytic unit such as the photosynthesis system I (PSI) reaction center of the protein-chlorophyll complex isolated from chloroplasts. The method employs a photo-biomolecular metal deposition technique for precisely controlled nucleation and growth of metallic clusters/particles, e.g., platinum, palladium, and their alloys, etc., as well as for thin-film formation above the surface of a solid substrate. The photochemically mediated technique offers numerous advantages over traditional deposition methods including quantitative atom deposition control, high energy efficiency, and mild operating condition requirements.

  13. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1985-01-01

    Research activities in Cosmic Rays, Gamma Rays, and Astrophysical Plasmas supported under NASA Grant NGR 05-002-160 are discussed. The report is divided into sections which describe the activities, followed by a bibliography. This group's research program is directed toward the investigation of the astrophysical aspects of cosmic rays and gamma rays and of the radiation and electromagnetic field environment of the Earth and other planets. These investigations are carried out by means of energetic particle and photon detector systems flown on spacecraft and balloons.

  14. The cooling of particle beams

    SciTech Connect

    Sessler, A.M.

    1994-10-01

    A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling with beam coupling. Laser Cooling has provided beams of the lowest temperatures, namely 1 mK, but only for ions and only for the longitudinal temperature. Recent theoretical work has suggested how laser cooling, with the coupling of beam motion, can be used to reduce the ion beam temperature in all three directions. The majority of this paper is devoted to describing laser cooling and laser cooling with beam coupling.

  15. Discrete Element Modeling of Triboelectrically Charged Particles

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.; Calle, Carlos I.; Weitzman, Peter S.; Curry, David R.

    2008-01-01

    Tribocharging of particles is common in many processes including fine powder handling and mixing, printer toner transport and dust extraction. In a lunar environment with its high vacuum and lack of water, electrostatic forces are an important factor to consider when designing and operating equipment. Dust mitigation and management is critical to safe and predictable performance of people and equipment. The extreme nature of lunar conditions makes it difficult and costly to carry out experiments on earth which are necessary to better understand how particles gather and transfer charge between each other and with equipment surfaces. DEM (Discrete Element Modeling) provides an excellent virtual laboratory for studying tribocharging of particles as well as for design of devices for dust mitigation and for other purposes related to handling and processing of lunar regolith. Theoretical and experimental work has been performed pursuant to incorporating screened Coulombic electrostatic forces into EDEM, a commercial DEM software package. The DEM software is used to model the trajectories of large numbers of particles for industrial particulate handling and processing applications and can be coupled with other solvers and numerical models to calculate particle interaction with surrounding media and force fields. While simple Coulombic force between two particles is well understood, its operation in an ensemble of particles is more complex. When the tribocharging of particles and surfaces due to frictional contact is also considered, it is necessary to consider longer range of interaction of particles in response to electrostatic charging. The standard DEM algorithm accounts for particle mechanical properties and inertia as a function of particle shape and mass. If fluid drag is neglected, then particle dynamics are governed by contact between particles, between particles and equipment surfaces and gravity forces. Consideration of particle charge and any tribocharging and

  16. ) Composites Containing Nanoparticles and Larger Particles

    NASA Astrophysics Data System (ADS)

    Ghanaraja, S.; Nath, S. K.; Ray, S.

    2014-07-01

    The composites reinforced with nanoparticles result in improved strength and ductility while those containing coarser particles of micron size have limited ductility. The present study investigates the outcome of mechanical properties in a composite reinforced simultaneously with coarse and fine particles. High energy milling of manganese dioxide particles with excess of aluminum powder ensures that nanoparticles generated, either of MnO2 or alumina, are mostly separate and surrounded by aluminum particles. The milled powder when added to aluminum alloy melt, the excess aluminum particles will melt leaving behind separate oxide nanoparticles without significant agglomeration. Different amounts of milled powder mix have been stirred into molten aluminum alloy where nanoparticles of MnO2 react with melt to form alumina. The resulting slurry is cast into composites, which also contains coarser (nearly micron size) alumina particles formed by internal oxidation of the melt during processing. The microstructure of the composites shows good distribution of both the size categories of particles without significant clustering. The oxide particles are primarily γ-alumina in a matrix of aluminum-magnesium-manganese alloy containing some iron picked up from the stirrer. These composites fail during tensile test by ductile fracture due to debonding of coarser particles. The presence of nanoparticles along with coarser particles in a composite improves both strength and ductility considerably, presumably due to delay in debonding of coarser particles to higher stress because of reduced mismatch in extension caused by increased strain hardening in presence of nanoparticles in the matrix. The composites containing only coarser oxide particles show limited strength and ductility attributed to early debonding of particles at a relatively lower stress due to larger mismatch in extension between matrix and larger particles. Higher addition of powder mix beyond a limit, however

  17. Experimental Investigation of Particle Deagglomeration using Turbulence

    NASA Astrophysics Data System (ADS)

    Köksoy, Çaǧatay; Ertunç, Özgür; Hüttner, Sebastian; Wachtel, Herbert; Delgado, Antonio

    2011-12-01

    The effect of turbulence on powder aerosol deagglomeration was investigated. Two impinging jets were used to generate turbulence. Lactose particles, whose fully dispersed fine particle fraction (FPF) - number percentage of the particles whose diameter smaller than 5 μm- is above 90 %, were applied as aerosol powder. The particle size distribution after the dispersion unit were measured by using phase Doppler anemometer (PDA) and turbulence level were quantified at the impingement point of two jets with laser Doppler anemometer. As the turbulence level increases turbulent time and length scales decrease, and the ratio of fine particle fraction (FPF) increases from 36% to 86%.

  18. Optical double-slit particle measuring system

    DOEpatents

    Tichenor, D.A.; Wang, J.C.F.; Hencken, K.R.

    1982-03-25

    A method for in situ measurement of particle size is described. The size information is obtained by scanning an image of the particle across a double-slit mask and observing the transmitted light. This method is useful when the particle size of primary interest is 3..mu..m and larger. The technique is well suited to applications in which the particles are non-spherical and have unknown refractive index. It is particularly well suited to high temperature environments in which the particle incandescence provides the light source.

  19. Flow visualization for Lagrangian particle methods

    SciTech Connect

    Glass, M.W.; Kempka, S.N.

    1994-05-01

    In particle methods, each particle represents a finite region over which there is a distribution of the field quantity of interest. The field value at any point is calculated by summing the distribution functions for all the particles. This summation procedure does not require the use of any connectivities to generate continuous fields. Various AVS modules and networks have been developed that enable us to visualize the results from particle methods. This will be demonstrated by visualizing a numerical simulation of a rising, chaotic bubble. In this fluid dynamics simulation, each particle represents a region with a specified vorticity distribution.

  20. Deformed Carroll particle from 2 + 1 gravity

    NASA Astrophysics Data System (ADS)

    Kowalski-Glikman, Jerzy; Trześniewski, Tomasz

    2014-10-01

    We consider a point particle coupled to 2 + 1 gravity, with de Sitter gauge group SO (3 , 1). We observe that there are two contraction limits of the gauge group: one resulting in the Poincaré group, and the second with the gauge group having the form AN (2) ⋉ an (2) *. The former case was thoroughly discussed in the literature, while the latter leads to the deformed particle action with de Sitter momentum space, like in the case of κ-Poincaré particle. However, the construction forces the mass shell constraint to have the form p02 =m2, so that the effective particle action describes the deformed Carroll particle.