WorldWideScience

Sample records for fine particles science

  1. Fractal aggregation and breakup of fine particles

    Directory of Open Access Journals (Sweden)

    Li Bingru

    2016-01-01

    Full Text Available Breakup may exert a controlling influence on particle size distributions and particles either are fractured or are eroded particle-by-particle through shear. The shear-induced breakage of fine particles in turbulent conditions is investigated using Taylor-expansion moment method. Their equations have been derived in continuous form in terms of the number density function with particle volume. It suitable for future implementation in computational fluid dynamics modeling.

  2. ELECTROSTATICALLY SUPPORTED MIXING OF FINE GRAINED PARTICLES

    Institute of Scientific and Technical Information of China (English)

    K.-E.; Wirth; M.; Linsenbühler

    2005-01-01

    The processing of fine-grained particles with diameters between 1 and 10 microns is difficult due to strong van-der-Waals attraction forces. In order to improve the handling properties, the fine-grained particles, i.e. host-particles,are coated with various nanoparticles, i.e. guest-particles. The mixing of fine-grained powders is influenced by particle-particle interactions. If these forces are distinctively used, both interactive and ordered mixtures can be produced.These particle mixtures consist of composite-particles that have new physical properties. These modified properties d epend strongly on the coating process, the diameter- and mass-relationship of the guest- and the host-particles. The properties of the composite-particles can systematically be adjusted to the requirements of industrial applications. For example, a laboratory bubbling fluidized bed can be used to describe the conveying behavior of the functionalized host-particles. Applications for the functionalized particles are in the pharmaceutical and the powder coating industries,e.g. enhanced dry powder inhalers and thin lacquer films. The present research compares three different mixing/coating processes. The composite-particles are characterized by TEM, SEM and with their fluidization characteristics. The coating process itself is monitored by the electrostatic charge of the particles.

  3. Fullerene fine particles adhere to pollen grains and affect their autofluorescence and germination

    Directory of Open Access Journals (Sweden)

    Aoyagi H

    2011-05-01

    Full Text Available Hideki Aoyagi, Charles U UgwuLife Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, JapanAbstract: Adhesion of commercially produced fullerene fine particles to Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica pollen grains was investigated. The autofluorescence of pollen grains was affected by the adhesion of fullerene fine particles to the pollen grains. The degree of adhesion of fullerene fine particles to the pollen grains varied depending on the type of fullerene. Furthermore, germination of Camellia japonica pollen grains was inhibited by the adhesion of fullerene fine particles.Keywords: Cryptomeria japonica, Chamaecyparis obtusa, Camellia japonica, autofluorescence, pollen grains, fullerene fine particle

  4. Charge neutrality of fine particle (dusty) plasmas and fine particle cloud under gravity

    Science.gov (United States)

    Totsuji, Hiroo

    2017-03-01

    The enhancement of the charge neutrality due to the existence of fine particles is shown to occur generally under microgravity and in one-dimensional structures under gravity. As an application of the latter, the size and position of fine particle clouds relative to surrounding plasmas are determined under gravity.

  5. Heterogeneous reactions on the surface of fine particles in the atmosphere

    Institute of Scientific and Technical Information of China (English)

    DING Jie; ZHU Tong

    2003-01-01

    Fine particles play an important role in the atmosphere. Research on heterogeneous reactions on the surface of fine particles is one of the frontier areas of atmospheric science. In this paper, physical and chemical characteristics of fine particles in the atmosphere and the interactions between trace gases and fine particles are described, methods used in heterogeneous reactions research are discussed in detail, progress in the study of heterogeneous reactions on the surface of fine particles in the atmosphere is summarized, existing importantquestions are pointed out and future research directions are suggested.

  6. Fine particle emissions from residential wood combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tissari, J.

    2008-07-01

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

  7. Some characteristics of fine beryllium particle combustion

    Science.gov (United States)

    Davydov, D. A.; Kholopova, O. V.; Kolbasov, B. N.

    2007-08-01

    Beryllium dust will be produced under plasma interaction with beryllium armor of the first wall in ITER. Exothermal reaction of this dust with water steam or air, which can leak into the reactor vacuum chamber in some accidents, gives concern in respect to reactor safety. Results of studies devoted to combustion of fine beryllium particles are reviewed in the paper. A chemically active medium and elevated temperature are prerequisite to the combustion of beryllium particles. Their ignition is hampered by oxide films, which form a diffusion barrier on the particle surface as a result of pre-flame oxidation. The temperature to initiate combustion of particles depends on flame temperature, particle size, composition of combustible mixture, heating rate and other factors. In mixtures enriched with combustible, the flame temperature necessary to ignite individual particles approaches the beryllium boiling temperature.

  8. Computer Models Simulate Fine Particle Dispersion

    Science.gov (United States)

    2010-01-01

    Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.

  9. FINE AND COARSE PARTICLES: CONCENTRATION RELATIONSHIPS RELEVANT TO EPIDEMIOLOGICAL STUDIES

    Science.gov (United States)

    Fine particles and coarse particles are defined in terms of the modal structure of particle size distributions typically observed in the atmosphere. Differences among the various modes are discussed. The fractions of fine and coarse particles collected in specific size ranges, ...

  10. The possibilities for measurement and characterization of diesel engine fine particles: A review

    Directory of Open Access Journals (Sweden)

    Petrović Velimir S.

    2011-01-01

    Full Text Available This review paper considers possible instrumentation for diesel engine fine particles exhaust emission evaluation. The modern diesel engines have extremely low particles emission almost at the level of measurement error of existing gravimetric measurement method. Since coarse particles are eliminated by new engine technologies, fine particles, with very negative effects on human health, dominate in the emission of current diesel engine. Therefore, it is necessary not only to measure mass of emitted particles but also to investigate other important particle characteristics as: particles number, particle size, particle number and mass distribution, particle active surface, particle composition etc. Therefore, existing measurement technologies used in aerosol science can be used also to study diesel engine particles properties. This most common instrumentation in aerosol technique is shortly reviewed in the paper with special attention on candidate instruments included in EU program on portable emissions measurement systems (PEMS.

  11. Spatial variability of fine particles in Parisian streets

    OpenAIRE

    Duché, Sarah; Beltrando, Gérard

    2012-01-01

    International audience; To study the spatial variability of airborne particles and to evaluate the personal and tourist exposure to fine particles in Paris, measurements of fine particles (PM2.5) concentrations have been made in Parisian streets in different mode of transport (bus, bike and walking), using a portable sensor. We use also meteorological parameters sensor (temperature,humidity and wind speed), a camera to view traffic and a GPS to compare with particles levels. PM2.5 levels are ...

  12. Selective separation of fine particles by a new flotation approach

    NARCIS (Netherlands)

    Mulleneers, H.A.E.; Koopal, L.K.; Bruning, H.; Rulkens, W.H.

    2002-01-01

    Fine particles often create problems in flotation applications. In this article a new laboratory flotation system for the selective separation of small particles was designed and tested. The device contains an active counter current sedimentation that should prevent entrainment of the fine

  13. EDITORIAL: Cluster issue on fine particle magnetism

    Science.gov (United States)

    Fiorani, D.

    2008-07-01

    This Cluster issue of Journal of Physics D: Applied Physics arises from the 6th International Conference on Fine Particle Magnetism (ICFPM) held in Rome during 9-12 October 2007 at the headquarters of the National Research Council (NCR). It contains a collection of papers based on both invited and contributed presentations at the meeting. The ICFPM Conferences have previously been held in Rome, Italy (1991), Bangor, UK (1996), Barcelona, Spain (1999), Pittsburgh, USA (2002) and London, UK (2004). The aim of this series of Conferences is to bring together the experts in the field of nanoparticle magnetism at a single forum to discuss recent developments in both theoretical and experimental aspects, and technological applications. The Conference programme included sessions on: new materials, novel synthesis and processing techniques, with special emphasis on self-organized magnetic arrays; theory and modelling; surface and interface properties; transport properties; spin dynamics; magnetization reversal mechanisms; magnetic recording media and permanent magnets; biomedical applications and advanced investigation techniques. I would like to thank the European Physical Society and the Innovative Magnetic and Superconducting Materials and Devices Project of the Materials and Devices Department and the Institute of Structure of Matter (ISM) of CNR for their support. Thanks are also due to the members of the Programme Committee, to the local Organizing Committee, chaired by Elisabetta Agostinelli and to all the Conference participants. I am also indebted to the many scientists who contributed to assuring the high-quality of this Cluster by donating their time to reviewing the manuscripts contained herein. Finally, I'd like to dedicate this issue to the memories of Jean Louis Dormann, a great expert in nanoparticle magnetism, who was one of the promoters and first organizers of this series of Conferences, and of Grazia Ianni, the Conference secretary, who died before her

  14. A hazard to health? Fine particles arouse worldwide interest

    Energy Technology Data Exchange (ETDEWEB)

    Karas, J.; Oesch, P.

    1998-07-01

    The most recent studies show that particles contained in the air that we breathe may have harmful effects on the health of asthmatics, children and old people in particular. Particle material found in ambient air is formed by emissions resulting from traffic, industry and other use of fuels. Nature`s own sources also have a significant effect on particle concentrations. The mechanisms by which fine particles may produce negative health effects are so far unknown. At present it is therefore impossible to assess the effects of emissions of fine particles resulting, for instance, from the use of fossil fuels

  15. Dispersion characteristics of fine particles in water, ethanol and kerosene

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Dispersion behavior of hydrophilic calcium carbonate particles and hydrophobic talcum particles in water, ethanol and kerosene media has been studied by sedimentation analysis. It is found that the dispersion of fine particles complies with the principle of polarity compatibility. That is to say, the dispersion effect will be improved when surface polarity of particles is similar to that of liquid media. The adsorption models of oleic acid on the surface of particles in water and ethanol are proposed.

  16. Fine Particle Matter (PM2.5) Design Value

    Data.gov (United States)

    U.S. Environmental Protection Agency — Fine particulate matter or PM2.5 (total mass of particles below 2.5 micron is diameter) is known to cause adverse health effects in humans.See the following websites...

  17. Separation of Fine Particles by Using Colloidal Gas Aphrons

    Institute of Scientific and Technical Information of China (English)

    E.A.Mansur; 王运东; 戴猷元

    2004-01-01

    This paper presents a method of separation of fine particles, of the order of a few microns or less, from aqueous media by flotation using colloidal gas aphrons (CGAs) generated in aqueous solutions. More than 150 experiments were conducted to study the effects of surfactant type, surfactant concentration, CGAs flow rate, and particle concentration on the removal efficiency (fine particles of polystyrene were used as a target compound). The results indicate that CGAs, generated from cationic surfactant of hexdecyltrimethyl ammonicum bromide (HTAB) and anionic surfactant of sodium dodecylbenzne sulfonate (SDBS), are an effective method for the separation off ine particles of polystyrene from wastewater. The flotation yields are higher than 97%.

  18. Pressure characteristics of a hydrocyclone for fine particle separation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li-xin; JIANG Ming-hu; SUN De-zhi; BELAIDI A; THEW M

    2006-01-01

    Solid-liquid hydrocyclones are mainly used to separate large particles, such as the particles of drilling fluid in petroleum industry, and large mineral particles. Till now the hydrocyclonic separation for fine particles is still a big problem. Basic separation principle of hydrocyclones and experimental research facility are simply introduced. The difficulty of separating fine particle is analyzed. Based on a solid-liquid hydrocyclone used for separating fine particles, relationships of dimensionless pressure characteristic parameters, i.e. Euler number and pressure drop ratio, with several main dimensionless parameters, such as split ratio, swirl number and gas-liquid ratio, were experimentally studied in detail. The research was carried out by using the hydrocyclonic separation experimental rig at the University of Bradford. It is shown that the less the size of particle, the less the value of radius of the balance orbit occupied by the particle, and then the more difficult for the particle to be separated. Experiments indicate that Euler number of the tested hydrocyclone increases with the rise of Reynolds number, split ratio, swirl number and gas-liquid ratio respectively, and the pressure drop ratio falls with the increase of Reynolds number, split ratio and swirl number respectively. It is concluded that the most effective way to decrease the unit energy dissipation of hydrocyclone is to reduce swirl number or gas-liquid ratio of the mixed media.

  19. Glassy behavior in magnetic fine particles

    CERN Document Server

    Muro, M G D; Labarta, A

    2000-01-01

    A detailed study of the static and dynamic magnetic properties of nanocrystalline barium hexaferrite powder was done. Particles of about 10 nm diameter exhibit the main features attributed to glassy behavior. Different results make evident the presence of strong interactions in the studied system. This glassy state is mostly attributed to the frustration induced by magnetic interactions between randomly distributed particles, although the surface spins contribution cannot be discarded. The effective energy barrier distribution obtained from the analysis of the time dependence of the thermoremanence in terms of the T ln (t/tau sub 0) scaling shows a maximum located at energies higher than the mean anisotropy energy barrier. When doing the relaxation experiments after field cooling at increasing fields, the obtained effective energy distribution progressively resembles the anisotropy energy distribution. Therefore, we demonstrate how the glassy state can be erased by applying a magnetic field.

  20. Transition metals in coarse, fine, very fine and ultra-fine particles from an interstate highway transect near Detroit

    Science.gov (United States)

    Cahill, Thomas A.; Barnes, David E.; Lawton, Jonathan A.; Miller, Roger; Spada, Nicholas; Willis, Robert D.; Kimbrough, Sue

    2016-11-01

    As one component of a study investigating the impact of vehicle emissions on near-road air quality, human exposures, and potential health effects, particles were measured from September 21 to October 30, 2010 on both sides of a major roadway (Interstate-96) in Detroit. Traffic moved freely on this 12 lane freeway with a mean velocity of 69 mi/hr. with little braking and acceleration. The UC Davis DELTA Group rotating drum (DRUM) impactors were used to collect particles in 8 size ranges at sites nominally 100 m south, 10 m north, 100 m north, and 300 m north of the highway. Ultra-fine particles were continuously collected at the 10 m north and 100 m north sites. Samples were analyzed every 3 h for mass (soft beta ray transmission), 42 elements (synchrotron-induced x-ray fluorescence) and optical attenuation (350-800 nm spectroscopy). A three day period of steady southerly winds along the array allowed direct measurement of freeway emission rates for coarse (10 > Dp > 1.0 μm), PM2.5, very fine (0.26 > Dp > 0.09 μm), and ultra-fine (Dp car and truck emission rates of 1973, this value would have been about 16 μg/m3, corrected down from the 19 μg/m3 PM5.0 using measured roadway dust contributions. This would have included 2.7 μg/m3 of lead, versus the 0.0033 μg/m3 measured. Very fine particles were distributed across the array with a relatively weak falloff versus distance. For the ultra-fine particles, emissions of soot and metals seen in vehicular braking studies correlated with traffic at the 10 m site, but only the soot was statistically significant at the 100 m north site. Otherwise, the 10 m north and 100 m north sites were essentially identical in mean concentration and highly correlated in time for most of the 5 week study. This result supports earlier publications showing the ability of very fine and ultra-fine particles to transport to sites well removed from the freeway sources. The concentrations of very fine and ultra-fine metals from brake wear and

  1. NARSTO fine-particle and ozone assessments.

    Science.gov (United States)

    Hales, Jeremy M

    2003-01-01

    NARSTO, a tri-national North American consortium for applied tropospheric pollution research, conducts periodic assessments of air-pollution behavior to provide an information interface between the research community and individuals working in policy analysis and air-quality management. The first of these, entitled An Assessment of Tropospheric Ozone Pollution--A North American Perspective, appeared in late 2000 and has been circulated widely throughout the United States, Canada, Mexico, Europe, and South America. The second (currently) entitled NARSTO Assessment of the Atmospheric Science on Particulate Matter, is presently in its third-draft phase and is available for general review. A fourth draft, incorporating comments from the current review stage, will be submitted in January 2002 to a tri-national review committee composed of the Canadian Royal Society, the US National Academy of Sciences, and the Mexican Red de Desarrollo e Investigación de la Calidad del Aire en Grandes Ciudades. Finalization of the document will follow this review, which will conclude in July 2000. Publication is expected in December 2002. These two assessments contain substantial amounts of policy-relevant information, which is of interest to the research community as well as those working in policy analysis and air-quality management. This presentation provides a brief overview of features and findings of the two documents.

  2. EFFECTS OF GAS TYPE AND TEMPERATURE ON FINE PARTICLE FLUIDIZATION

    Institute of Scientific and Technical Information of China (English)

    Chunbao Xu; J.-X. Zhu

    2006-01-01

    The influence of gas type (helium and argon) and bed temperature (77-473 K) on the fluidization behaviour of Geldart groups C and A particles was investigated. For both types of particles tested, i.e., Al2O3 (4.8 μm) and glass beads (39 μm), the fluidization quality in different gases shows the following priority sequence: Ar>He. In the same gaseous atmosphere, the particles when fluidized at an elevated temperature usually show larger bed voidages, higher bed pressure drops, and a lower umf for the group A powder, all indicating an enhancement in fluidization quality. Possible mechanisms governing the operations of gas type and temperature in influencing the fluidization behaviours of fine particles have been discussed with respect to the changes in both gas properties and interparticle forces (on the basis of the London-van der Waals theory). Gas viscosity (varying significantly with gas-type and temperature) proves to be the key parameter that influences the bed pressure drops and umf in fluidization of fine particles, while the interparticle forces (also varying with gas-type and temperature) may play an important role in fine-particle fluidization by affecting the expansion behaviour of the particle-bed.

  3. Deposition of fine and ultrafine particles on indoor surface materials

    DEFF Research Database (Denmark)

    Afshari, Alireza; Reinhold, Claus

    2008-01-01

    -scale test chamber. Experiments took place in a 32 m3 chamber with walls and ceiling made of glass. Prior to each experiment the chamber was flushed with outdoor air to reach an initial particle concentration typical of indoor air in buildings with natural ventilation. The decay of particle concentrations...... The aim of this study was the experimental determination of particle deposition for both different particle size fractions and different indoor surface materials. The selected surface materials were glass, gypsum board, carpet, and curtain. These materials were tested vertically in a full...... was monitored. Seven particle size fractions were studied. These comprised ultrafine and fine particles. Deposition was higher on carpet and curtain than on glass and gypsum board. Particles ranging from 0.3 to 0.5 µm had the lowest deposition. This fraction also has the highest penetration and its indoor...

  4. Turbidimetric method for evaluation of photocatalytic activities of suspended fine particles

    Directory of Open Access Journals (Sweden)

    Hideki Aoyagi

    2010-10-01

    Full Text Available Hideki Aoyagi1, Katsumi Yabusaki21Life Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; 2Electronics and Optics Research Laboratory, Kowa Ltd, Chofugaoka, Chofu City, Tokyo, JapanAbstract: A spectrophotometer with special cuvette was developed for evaluating the photocatalytic activities of suspended fine particles. The spectrophotometer can continuously irradiate UV light using LED to the sample solution, and changes in the absorbance at 664 nm during photocatalytic degradation of methylene blue (MB were monitored continuously. From the onset of MB degradation, the absorbance decreased and reached a steady value at the end of the reaction. This process was expressed by first order kinetics and the photocatalytic activities of various fine particles could be evaluated quantitatively based on the reaction rate constant (k. The effect of photocatalysis using various TiO2 fine particles on the physiological activities of Euglena gracilis was related with k value.Keywords: photocatalyst, fine nano sized particles, specialized spectrophotometer, Euglena gracilis, rate constant

  5. Measurements of Ultra-fine and Fine Aerosol Particles over Siberia: Large-scale Airborne Campaigns

    Science.gov (United States)

    Arshinov, Mikhail; Paris, Jean-Daniel; Stohl, Andreas; Belan, Boris; Ciais, Philippe; Nédélec, Philippe

    2010-05-01

    In this paper we discuss the results of in-situ measurements of ultra-fine and fine aerosol particles carried out in the troposphere from 500 to 7000 m in the framework of several International and Russian State Projects. Number concentrations of ultra-fine and fine aerosol particles measured during intensive airborne campaigns are presented. Measurements carried over a great part of Siberia were focused on particles with diameters from 3 to 21 nm to study new particle formation in the free/upper troposphere over middle and high latitudes of Asia, which is the most unexplored region of the Northern Hemisphere. Joint International airborne surveys were performed along the following routes: Novosibirsk-Salekhard-Khatanga-Chokurdakh-Pevek-Yakutsk-Mirny-Novosibirsk (YAK-AEROSIB/PLARCAT2008 Project) and Novosibirsk-Mirny-Yakutsk-Lensk-Bratsk-Novosibirsk (YAK-AEROSIB Project). The flights over Lake Baikal was conducted under Russian State contract. Concentrations of ultra-fine and fine particles were measured with automated diffusion battery (ADB, designed by ICKC SB RAS, Novosibirsk, Russia) modified for airborne applications. The airborne ADB coupled with CPC has an additional aspiration unit to compensate ambient pressure and changing flow rate. It enabled to classify nanoparticles in three size ranges: 3-6 nm, 6-21 nm, and 21-200 nm. To identify new particle formation events we used similar specific criteria as Young et al. (2007): (1) N3-6nm >10 cm-3, (2) R1=N3-6/N621 >1 and R2=N321/N21200 >0.5. So when one of the ratios R1 or R2 tends to decrease to the above limits the new particle formation is weakened. It is very important to notice that space scale where new particle formation was observed is rather large. All the events revealed in the FT occurred under clean air conditions (low CO mixing ratios). Measurements carried out in the atmospheric boundary layer over Baikal Lake did not reveal any event of new particle formation. Concentrations of ultra-fine

  6. Modeling of Fine-Particle Formation in Turbulent Flames

    Science.gov (United States)

    Raman, Venkat; Fox, Rodney O.

    2016-01-01

    The generation of nanostructured particles in high-temperature flames is important both for the control of emissions from combustion devices and for the synthesis of high-value chemicals for a variety of applications. The physiochemical processes that lead to the production of fine particles in turbulent flames are highly sensitive to the flow physics and, in particular, the history of thermochemical compositions and turbulent features they encounter. Consequently, it is possible to change the characteristic size, structure, composition, and yield of the fine particles by altering the flow configuration. This review describes the complex multiscale interactions among turbulent fluid flow, gas-phase chemical reactions, and solid-phase particle evolution. The focus is on modeling the generation of soot particles, an unwanted pollutant from automobile and aircraft engines, as well as metal oxides, a class of high-value chemicals sought for specialized applications, including emissions control. Issues arising due to the numerical methods used to approximate the particle number density function, the modeling of turbulence-chemistry interactions, and model validation are also discussed.

  7. Dynamics of fine particles in liquid-solid fluidized beds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis of the Local Equilibrium Model (LEM), fine particles with large Richardson-Zaki exponent n show, under certain conditions during bed expansion and collapse, different dynamic behavior from particles with small n. For an expansion process there may be a concentration discontinuity propagating upward from the distributor, and, on the contrary, for a collapse process there may be a progressively broadening and upward-propagating continuous transition zone instead of discontinuity. The predictions of the bed height variation and the discontinuity trace have been validated experimentally.

  8. Characterization of ultrafine and fine particles from CHP Plants

    Energy Technology Data Exchange (ETDEWEB)

    2009-08-15

    Samples of particles collected at CHP plants in the project 'Survey of emissions from CHP Plants' have been analysed in this project to give information on the morphology and chemical composition of individual particle size classes. The objective of this project was to characterize ultrafine and fine particles emitted to the atmosphere from Danish CHP plants. Nine CHP plants were selected in the Emission Survey Project as being representative for the different types of CHP plants operating in Denmark: 1) Three Waste-to Energy (WTE) plants. 2) Three biomass fired (BM) plants (two straw fired, one wood/saw dust fired). 3) Two gas fired (GF) plants (one natural gas, one landfill gas fired). 4) One gasoil (GO) fired plant. At the WTE and BM plants, various types of emission control systems implemented. The results from these plants represent the composition and size distribution of combustion particles that are emitted from the plants emission control systems. The measured emissions of particles from the waste-to-energy plants WTE1-3 are generally very low. The number and mass concentrations of ultrafine particles (PM{sub 0.1}) were particularly low in the flue gas from WTE2 and WTE3, where bag filters are used for the reduction of particle emissions. The EDX analysis of particles from the WTE plants indicates that the PM{sub 0.1} that penetrates the ECS at WTE can contain high fractions of metals such as Fe, Mn and Cu. The SEM analysis of particles from WTE1-3 showed that the particles were generally porous and irregular in shape. The concentrations of particles in the flue gas from the biomass plants were generally higher than found for the WTE plants. The time series results showed that periodical, high concentration peaks of PM emissions occur from BM1 and BM2. The chemical composition of the particles emitted from the three biomass plants is generally dominated by C, O and S, and to some extend also Fe and Si. A high amount of Cu was found in selected

  9. EPA Finalizes Initial Area Designations for the 2012 National Air Quality Standard for Fine Particles - Dec 2014

    Science.gov (United States)

    After considering state and tribal recommendations, reviewing the most recent certified fine particle air quality data, and emissions that contribute fine particle pollution, EPA has completed initial designations for the 2012 annual fine particle standard

  10. Enhancement of fine particle filtration with efficient humidification☆

    Institute of Scientific and Technical Information of China (English)

    Yumei Zhang; Weidong Zhang; Zhengyu Yang; Junteng Liu; Fushen Yang; Ning Li; Le Du⁎

    2016-01-01

    Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes, pressure drop of compact dust cake causes problems in efficiency and economy, which has received increasing at-tention and stil remains chal enging. In this study, we developed a novel technique to intensify the filtration of fine particles with efficient humidification. Two strategies for humidification, including ultrasonic atomization and steam humidification (control ing of ambient humidity), were employed and proved to be both effective. The re-generation frequency of the filter could be reduced by 55%with ultrasonic atomization, while steam humidification could lead to a 78%reduction in regeneration frequency. The effect of operating conditions on pressure drop and the mass loading during filtration were investigated. The dust cake showed a loose and porous structure with an opti-mized droplet-to-particle ratio. With the ratio of 1.53 and 0.0282, the maximum mass loading was 552 g·m−2 upon the ultrasonic atomization and 720 g·m−2 upon the steam humidification. The results show that humidification could slow down the increase of pressure drop during filtration and improve the efficiency of process.

  11. Performance of a New Fine Particle Impact Damper

    Directory of Open Access Journals (Sweden)

    Guangqiang Han

    2008-09-01

    Full Text Available The energy dissipation mechanisms of conventional impact damper (CID are mainly momentum exchange and friction. During the impact process, a lot of vibration energy cannot be exhausted but reverberated among the vibration partners. Besides, the CID may produce the additional vibration to the system or even amplify the response in the low-frequency vibration. To overcome these shortcomings, this paper proposes a new fine particle impact damper (FPID which for the first time introduces the fine particle plastic deformation as an irreversible energy sink. Then, the experiments of the cantilevered beam with the CID and that with the FPID are, respectively, carried out to investigate the behavior of FPID. The experimental results indicate that the FPID has a better performance in vibration damping than in the CID and the FPID works well in control of the vibration with frequency lower than 50 Hz, which is absent to the non-obstructive particle damper. Thus, the FPID has a bright and significant application future because most of the mechanical vibration falls in the range of low freqency.

  12. Impact of ozonation on particle aggregation in mature fine tailings.

    Science.gov (United States)

    Liang, Jiaming; Tumpa, Fahmida; Pérez Estrada, Leonidas; Gamal El-Din, Mohamed; Liu, Yang

    2014-12-15

    The extraction of bitumen from the oil sands in Canada generates tonnes of mature fine tailings (MFT), consisting of a mineral matrix of sand, clay, and water, which without treatment requires thousands of years to fully consolidate. We assessed the performance of a novel ozonation method designed to enhance the settling of MFT and explored the mechanisms involved. The solid content of MFT obtained from oil sands tailings was adjusted to 1, 3, 5 wt % with water before applying 15, 30, and 60 min of ozonation. MFT settled after a short (15 min) ozonation treatment, resulting in a sample with clear released water on the top and condensed sludge at the bottom. The water chemistry characteristics, particles' surface charge and chemical bonding were measured. Ozonation led to the increased organic acids concentrations in MFT suspension through converting of organic matter from high to low molecular weight, and detaching organic coating on MFT particles. The pH and the concentrations of ions in the MFT suspension were changed significantly, an association of metal ions with MFT particles was promoted, and the surface charges of MFT particles were neutralized. Consequently, the MFT suspension was destabilized and MFT particle precipitation was observed.

  13. Deviation from the superparamagnetic behaviour of fine-particle systems

    CERN Document Server

    Malaescu, I

    2000-01-01

    Studies concerning superparamagnetic behaviour of fine magnetic particle systems were performed using static and radiofrequency measurements, in the range 1-60 MHz. The samples were: a ferrofluid with magnetite particles dispersed in kerosene (sample A), magnetite powder (sample B) and the same magnetite powder dispersed in a polymer (sample C). Radiofrequency measurements indicated a maximum in the imaginary part of the complex magnetic susceptibility, for each of the samples, at frequencies with the magnitude order of tens of MHz, the origin of which was assigned to Neel-type relaxation processes. The static measurements showed a Langevin-type dependence of magnetisation M and of susceptibility chi, on the magnetic field for sample A. For samples B and C deviations from this type of dependence were found. These deviations were analysed qualitatively and explained in terms of the interparticle interactions, dispersion medium influence and surface effects.

  14. Observation of fine particle aggregating behavior induced by high intensity conditioning using high speed CCD

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The aggregating behavior between bubbles and particles induced by high intensity conditioning (HIC) was studied using high speed CCD technique. Bubble size measurement was conducted, and the attachment behavior between bubbles and particles in HIC cell and flotation cell were observed. The results show that in HIC cell, high intensity conditioning creates an advantage environment for the formation of small size bubble due to hydrodynamic cavitations, and these fine bubbles have high probability of bubble-particle collision,which will enhance fine particle flotation. The bubble-particle attachment experiments indicate that in high intensity conditioning cell, a lot of fine bubbles are produced in situ on the surface of fine particles, and most of fine particles are aggregated under the bridging action of fine bubbles. The observation of bubble-particle interaction in flotation cell illustrates that aggregates created by HIC can be loaded more easily by big air bubble in flotation cell than those created by normal conditioning.

  15. Optical measurement of anisotropic magnetic susceptibility for diamagnetic fine particles

    Science.gov (United States)

    Kitamura, Naoyuki; Takahashi, Kohki; Mogi, Iwao; Awaji, Satoshi; Watanabe, Kazuo

    2016-01-01

    We have developed an apparatus that allows the observation of the transient rotational motion of fine particles under a high magnetic field in order to determine anisotropic magnetic susceptibility. The anisotropic susceptibilities of spherical nanoparticles of bismuth and commercially available carbon nanofibers were determined. The estimated Δχ = 3.9 × 10-5 of spherical bismuth nanoparticles with a diameter of 370 nm was fairly consistent with the value determined previously by the magnetic field dependence of diffraction peak intensity in the X-ray diffraction (XRD) pattern, but was slightly smaller than the value for the bulk crystal. In contrast, the transient behavior of carbon nanofibers did not obey the theoretical motion of a single crystal. The wide distribution of fiber lengths, the irregularity of the structure in the fiber, and the connections between the fibers are suggested for the anomalous behavior.

  16. Simulated annealing: an application in fine particle magnetism

    Energy Technology Data Exchange (ETDEWEB)

    Legeratos, A.; Chantrell, R.W.; Wohlfarth, E.P.

    1985-07-01

    Using a model of a system of interacting fine ferromagnetic particles, a computer simulation of the dynamical approach to local or global minima of the system is developed for two different schedules of the application of ac and dc magnetic fields. The process of optimization, i.e., the achievement of a global minimum, depends on the rate of reduction of the ac field and on the symmetry of the ac field cycles. The calculations carried out to illustrate these effects include remanence curves and the zero field remanence for both schedules under different conditions. The growth of the magnetization during these processes was studied, and the interaction energy was calculated to best illustrate the optimization.

  17. An investigation into the effects of particle texture, water content and parallel plates' diameters on rheological behavior of fine sediment

    Institute of Scientific and Technical Information of China (English)

    Masoumeh Moayeri Kashani; Lai Sai Hin; Shaliza Binti Ibrahim; Nik Meriam Binti Nik Sulaiman; Fang Yenn Teo

    2016-01-01

    Siltation, a phenomenon resulted from the presence of fine particles in an aqueous environment, dominated by silt and clay, is a known and common environmental issue worldwide. The accumulation of fine sediments engenders murky water with low oxygen levels, which leads to the death of aquatic life. Thus, investigating the physical and mechanical properties of fine sediment by rheological methods has expanded. Rheology is the science of deformation and flow of matter in stress. This survey investigates the rheological behavior of six samples of soil as the fine particles structure (D<63μm) from different regions of Malaysia by using a rotational rheometer with a parallel-plate measuring (using two sizes:25 mm and 50 mm) device to explore the flow and viscoelastic properties of fine particles. The samples were examined in two rheological curve and amplitude sweep test methods to investigate the effect of water content ratio, texture, and structure of particles on rheological properties. It was found that the content of fine sand, clay, and silt had an effect on the stiffness, structural stability, and shear behavior. Thus, the pseudoplastic and viscoelastic behavior are respectively shown. Moreover, the amount of fine sediments present in water i.e. the concentration of these particles, has a direct effect on the rheological curve. A reduction in viscosity of samples with higher concentrations of water has been observed. As a consequence, a considerable quantity of fine sediments are distributed within the water body and remain suspended over the time. As a result, the sedimentation rate slows down. It needs to be asserted that the storage modulus G’ , loss modulus G″, and yield point can vary depending on particle type. The G’ and G″were instigated for samples (70%and 45%concentrations) that demonstrated viscoelastic characteristics using the same rotational rheometer with a parallel-plate measuring device.

  18. AP的安全制备%Safe Preparations of Fine Ammonium Perchlorate Particles

    Institute of Scientific and Technical Information of China (English)

    Makoto Kohga

    2006-01-01

    Fine AP particles are required to manufacture the AP-based composite propellants with a wide burning rate range for various applications,especially high burning rate propellants. However,it is difficult to prepare a fine AP safely. Some safe methods for preparing the fine AP particles are reported such as the spray-dry method and freeze-dry method. It is shown that the crystal habit modified AP particle is an effective oxidizer to enhance the burning rate.

  19. Preparation of UO_2 Fine Particle by Hydrolysis of Uranium(IV) Alkoxide

    OpenAIRE

    Satoh, Isamu; Takahashi, Mitsuyuki; Miura, Shigeyuki

    1997-01-01

    Fine particles of uranium(IV) dioxides were obtained by hydrolysis of uranium(IV) ethoxide which was synthesized by reacting uranium tetrachloride with sodium ethoxide. The monodispersed submicrometer particles were confirmed by SEM observation.

  20. Exposure to ultrafine and fine particles and noise during cycling and driving in 11 Dutch cities

    NARCIS (Netherlands)

    Boogaard, H.; Borgman, G.; Kamminga, J.; Hoek, H.

    2009-01-01

    Recent studies have suggested that exposures during traffic participation may be associated with adverse health effects. Traffic participation involves relatively short but high exposures. Potentially relevant exposures include ultrafine particles, fine particles (PM2.5) and noise. Simultaneously, d

  1. Coupling fine particle and bedload transport in gravel-bedded streams

    Science.gov (United States)

    Park, Jungsu; Hunt, James R.

    2017-09-01

    Fine particles in the silt- and clay-size range are important determinants of surface water quality. Since fine particle loading rates are not unique functions of stream discharge this limits the utility of the available models for water quality assessment. Data from 38 minimally developed watersheds within the United States Geological Survey stream gauging network in California, USA reveal three lines of evidence that fine particle release is coupled with bedload transport. First, there is a transition in fine particle loading rate as a function of discharge for gravel-bedded sediments that does not appear when the sediment bed is composed of sand, cobbles, boulders, or bedrock. Second, the discharge at the transition in the loading rate is correlated with the initiation of gravel mobilization. Third, high frequency particle concentration and discharge data are dominated by clockwise hysteresis where rising limb discharges generally have higher concentrations than falling limb discharges. These three observations across multiple watersheds lead to a conceptual model that fine particles accumulate within the sediment bed at discharges less than the transition and then the gravel bed fluidizes with fine particle release at discharges above the transition discharge. While these observations were individually recognized in the literature, this analysis provides a consistent conceptual model based on the coupling of fine particle dynamics with filtration at low discharges and gravel bed fluidization at higher discharges.

  2. Evaluation of particle growth systems for sampling and analysis of atmospheric fine particles

    Institute of Scientific and Technical Information of China (English)

    Dae Seong Kim; Sang Bum Hong; Jung-Taek Kwon; Kihong Park

    2011-01-01

    Three types of water-based condensational growth systems,which can enable particles to grow in size to facilitate sampling and subsequent chemical analysis,were evaluated.The first one is a mixing type growth system where aerosols are mixed with saturated water vapor,the second one is a thermal diffusive growth system where warm flow enters cold-walled tube,and the third one is a laminar flow type where cold flow enters a warm wet-wall tube.Hygroscopic sodium chloride (NaCl),ammonium sulfate ((NH4)2SO4) and ammonium nitrate (NH4NO3),and non-hygroscopic polystyrene latex (PSL) particles,in the size range of 50-400 nm,were used to determine their growth factors through the growth systems.Our data showed that the third-type growth system could enable particles to grow most efficiently regardless of their hygroscopic property.Collection efficiency of particles in the size range of 0.05-2.5 μm,in a continuous aerosol sampler after they passed through the third-type growth system was about 100%,suggesting that the third-type growth system would be the most useful among the tested growth systems for sampling and subsequent chemical analysis of fine and ultrafine particles.

  3. Protection against fine particle-induced pulmonary and systemic inflammation by omega-3 polyunsaturated fatty acids.

    Science.gov (United States)

    Li, Xiang-Yong; Hao, Lei; Liu, Ying-Hua; Chen, Chih-Yu; Pai, Victor J; Kang, Jing X

    2017-03-01

    Exposure to fine particulate matter, such as through air pollution, has been linked to the increased incidence of chronic diseases. However, few measures have been taken to reduce the health risks associated with fine particle exposure. The identification of safe and effective methods to protect against fine particle exposure-related damage is urgently needed. We used synthetic, non-toxic, fluorescent fine particles to investigate the physical distribution of inhaled fine particles and their effects on pulmonary and systemic inflammation in mice. Tissue levels of omega-3 fatty acids were elevated via dietary supplementation or the fat-1 transgenic mouse model. Markers of pulmonary and systemic inflammation were assessed. We discovered that fine particulate matter not only accumulates in the lungs but can also penetrate the pulmonary barrier and travel into other organs, including the brain, liver, spleen, kidney, and testis. These particles induced both pulmonary and systemic inflammation and increased oxidative stress. We also show that elevating tissue levels of omega-3 fatty acids was effective in reducing fine particle-induced inflammation, whether as a preventive method (prior to exposure) or as an intervention (after exposure). These results advance our understanding of how fine particles contribute to disease development and suggest that increasing tissue omega-3 levels may be a promising nutritional means for reducing the risk of diseases induced by particle exposure. Our findings demonstrate that elevating tissue omega-3 levels can prevent and treat fine particle-induced health problems and thereby present an immediate, practical solution for reducing the disease burden of air pollution. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Fine particle mass from the Diskus inhaler and Turbuhaler inhaler in children with asthma

    DEFF Research Database (Denmark)

    Bisgaard, H; Klug, B; Sumby, B S

    1998-01-01

    the varying age groups and inspiratory flow performances when compared to the Turbuhaler in terms of the proportion of the dose emitted at each particle size. This improvement is at the expense of a low fine particle mass and a high proportion of coarse particles from the Diskus as compared...

  5. Characterization and mapping of very fine particles in an engine machining and assembly facility.

    Science.gov (United States)

    Heitbrink, William A; Evans, Douglas E; Peters, Thomas M; Slavin, Thomas J

    2007-05-01

    Very fine particle number and mass concentrations were mapped in an engine machining and assembly facility in the winter and summer. A condensation particle counter (CPC) was used to measure particle number concentrations in the 0.01 microm to 1 microm range, and an optical particle counter (OPC) was used to measure particle number concentrations in 15 channels between 0.3 microm and 20 microm. The OPC measurements were used to estimate the respirable mass concentration. Very fine particle number concentrations were estimated by subtracting the OPC particle number concentrations from 0.3 microm to 1 microm from the CPC number concentrations. At specific locations during the summer visit, an electrical low pressure impactor was used to measure particle size distribution from 0.07 microm to 10 microm in 12 channels. The geometric mean ratio of respirable mass concentration estimated from the OPC to the gravimetrically measured mass concentration was 0.66 with a geometric standard deviation of 1.5. Very fine particle number concentrations in winter were substantially greater where direct-fire natural gas heaters were operated (7.5 x 10(5) particles/cm(3)) than where steam was used for heat (3 x 10(5) particles/cm(3)). During summer when heaters were off, the very fine particle number concentrations were below 10(5) particles/cm(3), regardless of location. Elevated very fine particle number concentrations were associated with machining operations with poor enclosures. Whereas respirable mass concentrations did not vary noticeably with season, they were greater in areas with poorly fitting enclosures (0.12 mg/m(3)) than in areas where state-of-the-art enclosures were used (0.03 mg/m(3)). These differences were attributed to metalworking fluid mist that escaped from poorly fitting enclosures. Particles generated from direct-fire natural gas heater operation were very small, with a number size distribution modal diameter of less than 0.023 microm. Aerosols generated by

  6. Temporal change in the {sup 137}Cs concentration ratio between coarse and fine particles in Fukushima

    Energy Technology Data Exchange (ETDEWEB)

    Kitayama, K.; Ohse, K.; Kawatsu, K.; Tsukada, H. [Fukushima University, 1 Kanayagawa, Fukushima-shi, Fukushima 960-1260 (Japan)

    2014-07-01

    Many radionuclides were released into the atmosphere by the Fukushima Daiichi Nuclear Power Plant accident, which was caused by the tsunami following the Tohoku Region Pacific Coast Earthquake on March 11, 2011. A major radionuclide released into the environment was radiocesium. Radiocesium has a long lifetime, which allows it to remain in the environment for a prolonged period. Most radiocesium exists in soil particles, and a potential source of radiocesium in coarse particles was resuspended from soil particles. Therefore, the {sup 137}Cs concentration ratios between coarse and fine particles were important for the evaluation of the radiocesium source. In this study, the {sup 137}Cs atmospheric concentrations in coarse and fine particles were measured in Fukushima. Airborne particles were collected from September 2012 to July 2013 at two sites, Fukushima and Date, which are 62 and 55 km, respectively, from the Fukushima Daiichi Nuclear Power Plant. The coarse and fine particles were categorized by a 50% cutoff diameter of 1.1 μm. The sampling filters were exchanged once every half month. The radioactivity of {sup 137}Cs in the samples was measured for 10800-86400 s by the Ge detector. In Fukushima, the total {sup 137}Cs concentration in coarse and fine particles ranged from 20 to 370 μBq m{sup -3}: 7-270 μBq m{sup -3} for coarse particles and 10-170 μBq m{sup -3} for fine particles. In Date, the total concentration ranged from 100 to 310 μBq m{sup -3}: 60-220 μBq m{sup -3} for coarse particles and 10-170 μBq m{sup -3} for fine particles. The {sup 137}Cs concentrations at the two sites were found to be comparable. The average concentration at the two sites for the course and fine particles were 110 and 55 μBq m{sup -3}, respectively, and the total concentration was 166 μBq m{sup -3}. The {sup 137}Cs concentration in coarse particles accounted for 30%-90% of the total concentration, with an average of 67%. On comparing with the ratio before the study, the

  7. FINE PARTICLE EXPOSURE IS ASSOCIATED WITH ALTERED VENTRICULAR REPOLARIZATION

    Science.gov (United States)

    Exposure to fine airborne particulate matter (PM2.5) has previously been associated with cardiac events, especially in older people with cardiovascular disease and in diabetics. This study examined the cardiac effects of short-term exposures to ambient PM2.5 in a prospective pane...

  8. Fine particle deposition at Vainguinim tourist beach, Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Jayakumar, S.; SanilKumar, V.; Ilangovan, D.

    . The beach sediments consist primarily shell fragments and quartz, with heavy mineral composed of ilmenits, magnetite and manganese. The black stain of the fine-grained heavy minerals deposited on the beach face reduces the aesthetics of the beach. This paper...

  9. Confined fluidization of fines in fixed bed of coarse particles

    Directory of Open Access Journals (Sweden)

    Buczek Bronisław

    2016-12-01

    Full Text Available Experiments on a confined fluidized bed system with various shapes of particles have been presented in the paper. Its influence on hydrodynamic properties in the whole range of gas velocity has been analysed. Relations allowing calculation of the Richardson-Zaki-type equation coefficients, including description of inter-particle void and gas pressure drop in such systems have been determined. Necessary condition for confined fluidization of non-spherical coarse particles has also been determined.

  10. Retention and Migration of Fine Organic Particles within an Agricultural Stream: Toenepi, Waikato, New Zealand

    Science.gov (United States)

    Drummond, J. D.; Davies-Colley, R.; Stott, R.; Sukias, J.; Nagels, J.; Sharp, A.; Packman, A. I.

    2013-12-01

    Fine organic particle dynamics are important to stream biogeochemistry, ecology, and transport of contaminant microbes. These particles migrate downstream through a series of deposition and resuspension events, which results in a wide range of residence times. This retention influences biogeochemical processing and in-stream stores of contaminant microbes that may mobilize during flood events and present a hazard to downstream uses such as water supplies and recreation. We are conducting studies to gain insights into organic particle dynamics in streams, with a campaign of experiments and modeling. The results should improve understanding of nutrient (C, N, P) spiraling and fine sediment movement in streams, and have particular application to microbial hazards. We directly measure microbial transport by including the indicator organism, E. coli, as a tracer, which is compared to a fluorescent inert particle tracer and conservative solute to gain insight on both microbial ecology and waterborne disease transmission. We developed a stochastic model to describe the transport and retention of fine suspended particles in rivers, including advective delivery of particles to the streambed, transport through porewaters, and reversible filtration within the streambed. Because fine particles are only episodically transported in streams, with intervening periods at rest in the bed, this transport process violates conventional advection-dispersion assumptions. Instead we adopt a stochastic mobile-immobile model formulation to describe fine particle transport. We apply this model to measurements of particle transport from multiple tracer experiments in an agricultural stream in the Waikato dairy region of New Zealand, and use the model to improve interpretation of baseflow particle dynamics. Our results show the importance of the benthic and hyporheic regions and in-stream vegetation as a reservoir for fine organic particles in streams.

  11. Microbial and Organic Fine Particle Transport Dynamics in Streams - a Combined Experimental and Stochastic Modeling Approach

    Science.gov (United States)

    Drummond, Jen; Davies-Colley, Rob; Stott, Rebecca; Sukias, James; Nagels, John; Sharp, Alice; Packman, Aaron

    2014-05-01

    Transport dynamics of microbial cells and organic fine particles are important to stream ecology and biogeochemistry. Cells and particles continuously deposit and resuspend during downstream transport owing to a variety of processes including gravitational settling, interactions with in-stream structures or biofilms at the sediment-water interface, and hyporheic exchange and filtration within underlying sediments. Deposited cells and particles are also resuspended following increases in streamflow. Fine particle retention influences biogeochemical processing of substrates and nutrients (C, N, P), while remobilization of pathogenic microbes during flood events presents a hazard to downstream uses such as water supplies and recreation. We are conducting studies to gain insights into the dynamics of fine particles and microbes in streams, with a campaign of experiments and modeling. The results improve understanding of fine sediment transport, carbon cycling, nutrient spiraling, and microbial hazards in streams. We developed a stochastic model to describe the transport and retention of fine particles and microbes in rivers that accounts for hyporheic exchange and transport through porewaters, reversible filtration within the streambed, and microbial inactivation in the water column and subsurface. This model framework is an advance over previous work in that it incorporates detailed transport and retention processes that are amenable to measurement. Solute, particle, and microbial transport were observed both locally within sediment and at the whole-stream scale. A multi-tracer whole-stream injection experiment compared the transport and retention of a conservative solute, fluorescent fine particles, and the fecal indicator bacterium Escherichia coli. Retention occurred within both the underlying sediment bed and stands of submerged macrophytes. The results demonstrate that the combination of local measurements, whole-stream tracer experiments, and advanced modeling

  12. Method of separating and de-watering fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Roe-Hoan

    2016-12-13

    A process for cleaning and dewatering hydrophobic particulate materials is presented. The process is performed in two steps: 1) agglomeration of the hydrophobic particles in a first hydrophobic liquid/aqueous mixture; followed by 2) dispersion of the agglomerates in a second hydrophobic liquid to release the water trapped within the agglomerates along with the entrained hydrophilic particles.

  13. Influence of Fine Metal Particles on Surface Discharge Characteristics of Outdoor Insulators

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2016-01-01

    Full Text Available Focusing on the influence of fine metal particles on the insulation characteristics of outdoor insulators, spherical micrometer-level iron powders were used to represent fine metal particles of different parameters on a polymer insulator specimen surface. Dynamic movement and lift-off behavior of fine particles, as well as the triggered surface discharges under AC voltage were investigated in a uniform electric field under different experimental conditions. The results reveal that the inception, propagation and intensity of surface discharges are significantly affected by the particle parameters, including particle size, amount and distributing characteristic. Based on the measurement of light emission during the flashover process using a high-speed camera, the process of surface discharge to flashover triggered by the fine metal particles were investigated to obtain a relationship between flashover voltage, discharge light intensity and particle parameters. It is suggested that particle size smaller than 28 µm and particle amount more than 40 mg in contact with the non-uniform distribution can cause a significant distortion and intensification of the electric field resulting in a higher risk of surface discharges leading to flashover. Such investigations can enhance the operating reliability of outdoor insulators subjected to these conditions.

  14. Abrasion of ultrafine WC-Co by fine abrasive particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Abrasive wear of a series of WC-(5%-14%, mass fiaction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used.The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage.This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

  15. [Effect of mixing of fine carrier particles on dry powder inhalation property of salbutamol sulfate (SS)].

    Science.gov (United States)

    Iida, K; Leuenberger, H; Fueg, L M; Müller-Walz, R; Okamoto, H; Danjo, K

    2000-01-01

    The most commonly used formulations for dry powder inhalations are binary ordered mixes composed of micronized drugs and coarse carriers. An optimal dry powder aerosol formulation should possess an optimal inhalation property and a good flow property. These characteristics are especially important for a multidose dry powder inheler (DPI). In the present study, model powder blend were prepared consisting of synthesized sugar (different particle sized isomalt; IM-PF, IM-FS, IM-F) as a carrier and micronized salbutamol sulfate (SS). These ordered mixtures were aerosolized by the multidose JAGO DPI (SkyePharma AG) and in vitro deposition properties (fine particle fraction, FPF) were evaluated by a twin impinger (TI) at a flow rate of 60 l/min. The separation property between SS and carrier particles was investigated by the centrifuge method and air jet sieve (AJS) method. It was found that FPF decreased with increasing carrier particle size. However, a large carrier particle possesses a good flow property. Therefore, the effect of mixing of fine carrier particles (IM-PF) into the large carrier particles (IM-FS) on dry powder inhalation property was investigated. When the proportion of IM-PF (fine carrier) increase from 0% to 25% of the total carrier powder blend, the FPF also increases from 16.7% to 38.9%. It is concluded that the effect of mixing of fine carrier particles might be a suitable method for improving the dry powder inhalation properties.

  16. A New Type of Non-Mechanical Valves for Recirculation of Fine Particles

    DEFF Research Database (Denmark)

    Azizaddini, Seyednezamaddin

    of the thesis is to design a new version of a non-mechanical valve for transportation of the particles and closing the loop in circulating or interconnected fluidized bed systems. As the primary proposal, combination of three assistive methods (tapered fluidized bed, mixture of coarse and fine particles...

  17. A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

    Science.gov (United States)

    A model for fine particle agglomeration in circulating fluidized bed absorbers (CFBAS) has been developed. It can model the influence of different factors on agglomeration, such as the geometry of CFBAs, superficial gas velocity, initial particle size distribution, and type of ag...

  18. Eddy Current Separation of Fine Non-Ferrous Particles from Bulk Streams

    NARCIS (Netherlands)

    Settimo, F.; Bevilacqua, P.; Rem, P.

    2004-01-01

    Recovery of fine non-ferrous metals from waste streams is a notoriously difficult problem in eddy current separation technology. Existing processes either have a low capacity or an incomplete recovery for particle sizes below 5 mm. In a new process, the particles are fed slightly wet to make them st

  19. Eddy Current Separation of Fine Non-Ferrous Particles from Bulk Streams

    NARCIS (Netherlands)

    Settimo, F.; Bevilacqua, P.; Rem, P.

    2004-01-01

    Recovery of fine non-ferrous metals from waste streams is a notoriously difficult problem in eddy current separation technology. Existing processes either have a low capacity or an incomplete recovery for particle sizes below 5 mm. In a new process, the particles are fed slightly wet to make them

  20. On the Accelerated Settling of Fine Particles in a Bidisperse Slurry

    Directory of Open Access Journals (Sweden)

    Leonid L. Minkov

    2015-01-01

    Full Text Available An estimation of increasing the volume average sedimentation velocity of fine particles in bidisperse suspension due to their capturing in the circulation zone formed in the laminar flow of incompressible viscous fluid around the spherical coarse particle is proposed. The estimation is important for an explanation of the nonmonotonic shape of the separation curve observed for hydrocyclones. The volume average sedimentation velocity is evaluated on the basis of a cellular model. The characteristic dimensions of the circulation zone are obtained on the basis of a numerical solution of Navier-Stokes equations. Furthermore, these calculations are used for modelling the fast sedimentation of fine particles during their cosedimentation in bidisperse suspension. It was found that the acceleration of sedimentation of fine particles is determined by the concentration of coarse particles in bidisperse suspension, and the sedimentation velocity of fine fraction is proportional to the square of the coarse and fine particle diameter ratio. The limitations of the proposed model are ascertained.

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

    Science.gov (United States)

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

    2016-04-01

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

  2. Numerical Model for Ultra-fine Particles in the Absence and Presence of Gravity

    Science.gov (United States)

    Dutt, Meenakshi; Elliott, James A.

    2009-06-01

    Length scales of particles and their surrounding medium strongly determines the nature of their interactions with one another and their responses to external fields. We are interested in systems of ultra-fine particles (0.1-1.0 micron) such as volcanic ash, soot from forest fires, solid aerosols, or fine powders for pharmaceutical inhalation applications. We have a developed a numerical model which captures the dominant physical interactions which control the behavior of these systems. The adhesive interactions between the particles use the Derjaguin-Muller-Toporov (DMT) adhesion theory along with the van der Waals attraction. The elastic restoring forces are modeled by the Hertz's contact model, and require details of material properties such as the Young's modulus and Poisson ratio. Commencing with a three dimensional gas of ultra-fine particles, the absence of gravity does not produce any noticeable clustering. The presence of gravity initially generates a large population of clusters with small number of particles, as the particles settle. The initial population of small clusters or single particles which have settled decrease with time as more particles, or clusters, agglomerate with one another. Our final results show clusters containing 10 to 100 particles, with a larger population of small clusters. We present details of the model, and some preliminary results which demonstrate the influence of the particle surface properties on the clustering dynamics of these systems, in the absence and presence of gravity (M. Dutt, J. A. Elliott, et al. in press).

  3. Fine-Tuning Two-Particle Interferometry; 2, Opacity Effects

    CERN Document Server

    Tomasik, Boris; Tomasik, Boris; Heinz, Ulrich

    1998-01-01

    We present a model study of single-particle spectra and two-particle Bose-Einstein correlations for opaque sources. We study the transverse mass dependence of the correlation radii R_\\perp, R_\\parallel and R_0 in the YKP parametrization and find a strong sensitivity of the temporal radius parameter R_0^2 to the source opacity. A simple comparison with the published data from 158 A GeV/c Pb+Pb collisions at CERN indicates that the pion source created in these collisions emits particles from the whole reaction volume and is not opaque. For opaque sources we find certain regions of inapplicability of the YKP parametrization which can be avoided by a slightly different parametrization for the correlator. The physical meaning of the modified parameters is briefly discussed.

  4. Moessbauer study of Martensitic transformation and collective magnetic excitations in Fe9Ni1 fine particles

    Institute of Scientific and Technical Information of China (English)

    H.M.Widatallah; 黄润生; 等

    1996-01-01

    The austenite to martensity ransformation in fine Fe90Ni.10 particles prepared by evaporation is studied by Moessbauer technique.Unlike bulk Fe.9Ni.1 which is entirely transformed to martensite.these particles show a remarkable austenite stability upon cooling upto liquid nitrogen temperature.This stability is associated with the oxide surface layer formed on the particles and also with their small size.A hyperfine field approach is employed to analyze the martensitic transformation in the particles.It is also shown that,in contrast with large particles ,the temperature variation of the Moessbauer average hyperfine field of the fine particles can be satisfactorily explained in terms of the collective magnetic excitations model.

  5. Effect of interparticle forces on the fluidization of fine particles

    Science.gov (United States)

    Baerns, M. G.; Ramaswami, D.

    1969-01-01

    Report studies elucidation and description of effect of interparticle forces on feasibility of gaseous fluidization of particles below 50 microns in diameter. Interparticle forces are determined by inclined-plane method. Study indicated that fluidizability is related to the interparticle adhesive force.

  6. Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

    Science.gov (United States)

    White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

    2013-12-01

    Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image

  7. Source Apportionment of Fine Particles in Xinzhen, Beijing

    Institute of Scientific and Technical Information of China (English)

    JIN; Xiang-chun; ZHANG; Gui-ying; XIAO; Cai-jin; WANG; Ping-sheng; WANG; Xing-hua; HUA; Long; YAO; Yong-gang; YUAN; Guo-jun; NI; Bang-fa

    2013-01-01

    As the capital city of China,Beijing often suffers from hazy weather recently.In order to improve air quality,it is of great importance to perform source apportionment and source trajectory.A total of 140airborne particulate matter samples were collected at Xinzhen from May,2007 to July,2013 and their chemical compositions were analyzed by Particle Induced X-ray Emission(PIXE)and Energy Disperse-X

  8. Characterization of silver nanoparticles synthesized on titanium dioxide fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Nino-Martinez, N [Facultad de Ciencias, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Martinez-Castanon, G A [Maestria en Ciencias Odontologicas, Facultad de EstomatologIa, UASLP, Avenida Manuel Nava 2, Zona Universitaria, San Luis PotosI, SLP (Mexico); Aragon-Pina, A [Instituto de Metalurgia, Facultad de IngenierIa, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Martinez-Gutierrez, F [Facultad de Ciencias Quimicas, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Martinez-Mendoza, J R [Facultad de Ciencias, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Ruiz, Facundo [Facultad de Ciencias, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico)

    2008-02-13

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO{sub 2} particles using a simple aqueous reduction method. The reducing agent used was NaBH{sub 4}; different molar ratios TiO{sub 2}:Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO{sub 2} particles and that the TiO{sub 2}:Ag molar ratio plays an important role. We used three different TiO{sub 2}Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO{sub 2} particles.

  9. Superamphiphobic nanofibrous membranes for effective filtration of fine particles.

    Science.gov (United States)

    Wang, Na; Zhu, Zhigao; Sheng, Junlu; Al-Deyab, Salem S; Yu, Jianyong; Ding, Bin

    2014-08-15

    The worldwide demands are rising for an energy-efficient and cost-effective approach that can provide advanced nanofibrous membranes with high filtration performance and superior antifouling properties. Here we report a novel synthesized fluorinated polyurethane (FPU) modified nanofibrous membrane optimized to achieve oil and non-oil aerosol particle filtration. By employing the FPU incorporation, the polyacrylonitrile/polyurethane (PAN/PU) composite membranes were endowed with superhydrophobicity with a water contact angle of 154° and superoleophobicity with an oil contact angle of 151°. Morphology, surface wettability, porous structure, and filtration performance could be manipulated by tuning the solution composition as well as the hierarchical structure. Furthermore, the as-prepared membranes can capture, for the first time, a range of different oil aerosol particles in a single-unit operation, with >99.9% filtration efficiency, by using the combined contribution of fiber diameter and surface roughness acting on the objective particles. Exemplified here by the construction of superamphiphobic nanofibrous membrane, numerous applications of this medium includes high efficiency particulate air filters, ultra-low penetration air filters, and respiratory protection equipment.

  10. Morphological study of Sr2CeO4 blue phosphor with fine particles

    Directory of Open Access Journals (Sweden)

    Janaína Gomes

    2004-10-01

    Full Text Available Morphological and spectroscopic studies of Sr2CeO4 blue phosphor in the form of fine particles prepared from a powdered multi-component precursor, via a combustion method, are reported. Samples were also prepared through a solid-state reaction and from a polymeric precursor for comparison. Citric acid or glycine as fuels in the combustion method lead to a mixture which is heated at 950 ºC for 4 h, resulting in spheroidal particles with a diameter between 250-550 nm. Samples from the polymeric precursor result in spheroidal particles (350-550 nm and from the solid-state reaction in irregular particles (~ 5 mum. Therefore, the combustion method is adequate for preparation of Sr2CeO4 in the form of spherical fine particles.

  11. Attractive particle interaction forces and packing density of fine glass powders.

    Science.gov (United States)

    Parteli, Eric J R; Schmidt, Jochen; Blümel, Christina; Wirth, Karl-Ernst; Peukert, Wolfgang; Pöschel, Thorsten

    2014-09-02

    We study the packing of fine glass powders of mean particle diameter in the range (4-52) μm both experimentally and by numerical DEM simulations. We obtain quantitative agreement between the experimental and numerical results, if both types of attractive forces of particle interaction, adhesion and non-bonded van der Waals forces are taken into account. Our results suggest that considering only viscoelastic and adhesive forces in DEM simulations may lead to incorrect numerical predictions of the behavior of fine powders. Based on the results from simulations and experiments, we propose a mathematical expression to estimate the packing fraction of fine polydisperse powders as a function of the average particle size.

  12. Heterogeneous Nucleation of Trichloroethylene Ozonation Products in the Formation of New Fine Particles

    Science.gov (United States)

    Wang, Ning; Sun, Xiaomin; Chen, Jianmin; Li, Xiang

    2017-01-01

    Free radicals in atmosphere have played an important role in the atmospheric chemistry. The chloro-Criegee free radicals are produced easily in the decomposition of primary ozonide (POZ) of the trichloroethylene, and can react with O2, NO, NO2, SO2 and H2O subsequently. Then the inorganic salts, polar organic nitrogen and organic sulfur compounds, oxygen-containing heterocyclic intermediates and polyhydroxy compounds can be obtained. The heterogeneous nucleation of oxidation intermediates in the formation of fine particles is investigated using molecular dynamics simulation. The detailed nucleation processes are reported. According to molecular dynamics simulation, the nucleation with a diameter of 2 nm is formed in the Organic Compounds-(NH4)2SO4-H2O system. The spontaneous nucleation is an important process in the formation of fine particles in atmosphere. The model study gives a good example from volatile organic compounds to new fine particles. PMID:28198438

  13. Heterogeneous Nucleation of Trichloroethylene Ozonation Products in the Formation of New Fine Particles

    Science.gov (United States)

    Wang, Ning; Sun, Xiaomin; Chen, Jianmin; Li, Xiang

    2017-02-01

    Free radicals in atmosphere have played an important role in the atmospheric chemistry. The chloro-Criegee free radicals are produced easily in the decomposition of primary ozonide (POZ) of the trichloroethylene, and can react with O2, NO, NO2, SO2 and H2O subsequently. Then the inorganic salts, polar organic nitrogen and organic sulfur compounds, oxygen-containing heterocyclic intermediates and polyhydroxy compounds can be obtained. The heterogeneous nucleation of oxidation intermediates in the formation of fine particles is investigated using molecular dynamics simulation. The detailed nucleation processes are reported. According to molecular dynamics simulation, the nucleation with a diameter of 2 nm is formed in the Organic Compounds-(NH4)2SO4-H2O system. The spontaneous nucleation is an important process in the formation of fine particles in atmosphere. The model study gives a good example from volatile organic compounds to new fine particles.

  14. The ozonolysis of primary aliphatic amines in fine particles

    Directory of Open Access Journals (Sweden)

    J. Zahardis

    2008-02-01

    Full Text Available The oxidative processing by ozone of the particulate amines octadecylamine (ODA and hexadecylamine (HDA is reported. Ozonolysis of these amines resulted in strong NO2 and NO3 ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitroalkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3 (HNO3. For ozonized mixed particles containing ODA or HDA + oleic acid (OL, with pO3≥3×10–7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines and stabilized Criegee intermediates (SCI or secondary ozonides (for amides from the fatty acid. The routes to amides via SCI and/or secondary ozonides were shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s. This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g.~NO2, NO3, formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

  15. The triggering of myocardial infarction by fine particles is enhanced when particles are enriched in secondary species

    Science.gov (United States)

    Previous studies have reported an increased risk of myocardial infarction (MI) associated with acute increases in PM concentration. Recently, we reported that MI/fine particle (PM2.5) associations may be limited to transmural infarctions. We used PM2.5 speci...

  16. The triggering of myocardial infarction by fine particles is enhanced when particles are enriched in secondary species

    Science.gov (United States)

    Previous studies have reported an increased risk of myocardial infarction (MI) associated with acute increases in PM concentration. Recently, we reported that MI/fine particle (PM2.5) associations may be limited to transmural infarctions. We used PM2.5 speci...

  17. Characterization of fine particle components in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, K. [Akita Prefectural Institute of Environmental Science, Yabase-Shimoyabase, Akita (Japan); Sera, K. [Iwate Medical Univ., Cyclotron Research Center, Takizawa, Iwate (Japan); Perales, J.G.; Garcia, F.A. [Centro Nacional de Investigacion y Capacitacion Ambiental (CENICA), Av. Michoacan y la Purisima Col. Vicentina C.P. 09340 Mexico (Mexico); Suzuki, H. [Environmental Data Analysis Laboratory, System Design, Inc., Shinagawa, Tokyo (Japan)

    1999-07-01

    Particulate matter (PM-3.9 and PM-15.8) samples were collected in the three zones at the Northeast, Southwest and Southeast suburbs of Mexico City, from July to August 1998, for one week for each sampling site. The concentrations of several elements in the PM-3.9 and PM-15.8 samples were determined by Particle Induced X-ray Emission (PIXE). In the PM-3.9 samples, 21 elements were determined for each zone, and Na, Mg, Al, Si, S, K, Ca, Ti, Fe, Cu, Zn and Pb are found to be the major elemental components. On the other hand, 22 elements including P were determined on the PM-15.8 samples, and the dominant elements were the same as in the PM-3.9. Factor analysis is applied to the 28 variables (14 elements for each PM-3.9 and PM-15.8 groups) and for 21 samples (seven days for three zones) in order to identify possible sources of the particles. The result of factor analysis allows to identify five major sources, being soil the major contributor. (author)

  18. NUMBER CONCENTRATION, SIZE DISTRIBUTION AND FINE PARTICLE FRACTION OF TROPOSPHERIC AND STRATOSPHERIC AEROSOLS

    Institute of Scientific and Technical Information of China (English)

    Li Xu; Guangyu Shi; Li Zhang; Jun Zhou; Yasunobu Iwasaka

    2003-01-01

    Aerosol observations were carried out at Xianghe Scientific Balloon Base (39.45°N, 117°E) using a stratospheric balloon. The particle number concentrations of the tropospheric and stratospheric aerosols were directly explored.The vertical distributions of the number concentration, number-size (that is, particle number versus particle size)distribution, and the fraction of fine particles (0.5 μm>r>0.15 μm/r>0.15 μm) are reported in this paper. The profiles of particle concentration present multi-peak phenomenon. The pattern of size distribution for atmospheric aerosol indicates a tri-modal (r=~0.2 μm, ~0.88 μm and ~7.0 μm) and a bi-modal (r=~0.13 μm and 2.0 μm). The number-size distribution almost fits the Junge distribution for particles with r<0.5 μm in the stratosphere of 1993 and the troposphere of 1994. But the distributions of coarse particles (r>0.5 μm) are not uniform. The number-size distribution exhibits also a wide size range in the troposphere of 1993. The results demonstrate that fine particles represent the major portion in the troposphere during the measurement period, reaching as high as 95% in 1994. Certain coarse particle peaks in the troposphere were attributed to clouds and other causes, and in the stratosphere to volcanic eruption. The stratospheric aerosol layer consists of unique fractions of fine or coarse particles depending on their sources. In summary, the process of gas-to-particles conversion was active and the coarse particles were rich over the Xianghe area. The measurements also demonstrate that the spatial and temporal atmospheric aerosol distributions are nonuniform and changeful.

  19. Microwave non-resonant absorption in fine cobalt ferrite particles

    Energy Technology Data Exchange (ETDEWEB)

    Mata-Zamora, M.E. [Depto. Investigacion Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, 04510 (Mexico)]. E-mail: memzamora@yahoo.com.mx; Montiel, H. [Depto. Investigacion Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Alvarez, G. [Depto. Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Saniger, J.M. [Depto. Investigacion Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Zamorano, R. [Escuela Superior de Fisica y Matematicas, IPN, 07738 (Mexico); Valenzuela, R. [Depto. Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 (Mexico)

    2007-09-15

    Cobalt ferrite particles of average crystallite size of 11 nm were obtained by a sol-gel process at 400 deg. C . The powders were annealed at temperatures of 500, 600, 700 and 800 deg. C in air. Derivative microwave power absorption (dP/dH) measurements were carried out as a function of magnetic field (H {sub DC}) at X band (9.4 GHz), in the field range -80-796 kA/m for all annealed temperatures. In order to compare the response of saturation magnetization measurements with high frequency measurements, we calculated the areas inside both the magnetization (A {sub M}) and the absorption hysteresis loops (A {sub LFS}). The dependence of these areas as a function of crystallite size is remarkably similar in both experiments.

  20. Dust-cloud structures behind a shock wave moving over a deposited layer of fine particles

    Institute of Scientific and Technical Information of China (English)

    WANG Boyi; XIONG Yi; CHEN Qian; A.N. OSIPTSOV

    2005-01-01

    The present paper investigates dispersed-phase flow structures of a dust cloud induced by a normal shock wave moving at a constant speed over a flat surface deposited with fine particles. In the shock-fitted coordinates, the general equations of dusty-gas boundary layer flows are formulated within the framework of a multi-fluid model and parametric numerical studies of the carrier- and dispersedphase flow fields are performed. The problem associated with crossing particle trajectories and the formation of local particle accumulation regions are solved by using the full Lagrangian method for the dispersed phase. The basic features of the near-wall two-phase flow under consideration including the role of Saffman force in the particle entrainment and the development of discontinuities or singularities in the particle density profiles are discussed. The effects associated with account of the non-uniformity of particle size and the finiteness of the particle Knudsen numbers are studied in detail.

  1. Filler effect of fine particle sand on the compressive strength of mortar

    Science.gov (United States)

    Jaturapitakkul, Chai; Tangpagasit, Jatuphon; Songmue, Sawang; Kiattikomol, Kraiwood

    2011-04-01

    The river sand, which is a non-pozzolanic material, was ground into 3 different particle sizes. Portland cement type I was replaced by the ground river sands at 10wt%-40wt% of binder to cast mortar. Compressive strengths of mortar were investigated and the filler effect of different fine particles of sand on the compressive strength of mortar was evaluated. The results show that the compressive strength of mortar contributed from the filler effect of smaller particles is higher than that of the coarser ones. The difference in compressive strength of mortar tends to be greater as the difference in ground river sand fineness increases. The results also suggest that ASTM C618 specification is not practically suitable for specifying pozzolan in concrete since the strength activity index of mortar containing ground river sand (high crystalline phase) with 33.8wt% of particles retained on a 45-μm sieve can pass the strength requirement.

  2. NUMERICAL SIMULATION OF FINE PARTICLE SEPARATION IN A ROTATIONAL TUBE SEPARATOR

    Institute of Scientific and Technical Information of China (English)

    Jinyu Jiao; Ying Zheng; Guogang Sun

    2005-01-01

    This paper presents a numerical analysis of gas-solid separation in a rotational tube separator. This separator which collects fine particles from gas in laminar flow is effective for fine particle separation. The separation efficiency and critical particle diameter of the separator were simulated using CFD package (FLUENT 6.0). The simulation showed that separation efficiency can be significantly decreased due to the presence of turbulence. The simulation also showed that the Saffman lift force has little effect on the efficiency of this separator. The critical particle diameter of this tube separator was also calculated theoretically. Some experimental data were provided to validate the simulation results. Comparison between experimental results and simulation predictions on separation efficiency showed satisfactory agreement.

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

    Institute of Scientific and Technical Information of China (English)

    Wang Leilei; Chen Wei; Lin Tao

    2008-01-01

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

  4. Hydrogeomorphology of the hyporheic zone: stream solute and fine particle interactions with a dynamic streambed

    Science.gov (United States)

    Harvey, J.W.; Drummond, J.D.; Martin, R.L.; McPhillips, L.E.; Packman, A.I.; Jerolmack, D.J.; Stonedahl, S.H.; Aubeneau, A.F.; Sawyer, A.H.; Larsen, L.G.; Tobias, C.R.

    2012-01-01

    Hyporheic flow in streams has typically been studied separately from geomorphic processes. We investigated interactions between bed mobility and dynamic hyporheic storage of solutes and fine particles in a sand-bed stream before, during, and after a flood. A conservatively transported solute tracer (bromide) and a fine particles tracer (5 μm latex particles), a surrogate for fine particulate organic matter, were co-injected during base flow. The tracers were differentially stored, with fine particles penetrating more shallowly in hyporheic flow and retained more efficiently due to the high rate of particle filtration in bed sediment compared to solute. Tracer injections lasted 3.5 h after which we released a small flood from an upstream dam one hour later. Due to shallower storage in the bed, fine particles were rapidly entrained during the rising limb of the flood hydrograph. Rather than being flushed by the flood, we observed that solutes were stored longer due to expansion of hyporheic flow paths beneath the temporarily enlarged bedforms. Three important timescales determined the fate of solutes and fine particles: (1) flood duration, (2) relaxation time of flood-enlarged bedforms back to base flow dimensions, and (3) resulting adjustments and lag times of hyporheic flow. Recurrent transitions between these timescales explain why we observed a peak accumulation of natural particulate organic matter between 2 and 4 cm deep in the bed, i.e., below the scour layer of mobile bedforms but above the maximum depth of particle filtration in hyporheic flow paths. Thus, physical interactions between bed mobility and hyporheic transport influence how organic matter is stored in the bed and how long it is retained, which affects decomposition rate and metabolism of this southeastern Coastal Plain stream. In summary we found that dynamic interactions between hyporheic flow, bed mobility, and flow variation had strong but differential influences on base flow retention and

  5. Speciated Fine Particle Deposition to a Forest Canopy Measured by Eddy-Correlation Mass Spectrometry

    Science.gov (United States)

    Allen, J. O.; Gonzales, D. A.; Delia, A. E.; Jimenez, J. L.; Smith, K. A.; Canagaratna, M.; Jayne, J. T.; Worsnop, D. R.

    2002-12-01

    Dry deposition serves as an important mechanism for the removal particles from the atmosphere and for the addition of material to ecosystems. Here we report on measurements of aerosol particle deposition using eddy-correlation mass spectrometry data collected during the PROPHET 2001 study which was conducted at the University of Michigan Biological Station in a north Michigan forest. Aerosol composition was measured with fast time response using the recently-developed Aerodyne Aerosol Mass Spectrometer (AMS) (Jayne et~al.,~2000). In the AMS, particles were focused using an aerodynamic lens. The aerosol was then expanded into a vacuum where aerodynamic particle size is determined by particle time-of-flight. The particles were then directed to an oven where semi-volatile components were flash vaporized. Vaporized components were ionized by electron impaction and detected using a quadrupole mass spectrometer. Thus the response of characteristic ions from fine aerosol particles (particle diameter, Dp, = 0.04-1.5 μm) were measured with a frequency of 10 Hz. A sonic anemometer was also deployed to measure wind velocity with a frequency of 10 Hz. Fluxes of aerosol species were then calculated using the well-known eddy-correlation method as the covariance of the vertical wind speed and the species concentration. These results demonstrate the new eddy-correlation mass spectrometry technique for measuring directly speciated fine particle deposition rates.

  6. [The analysis for silver iodide fine particles of TLC/FTIR matrix].

    Science.gov (United States)

    Zhu, Qing; Su, Xiao; Wu, Hai-Jun; Zhai, Yan-Jun; Xia, Jin-Ming; Buhebate; Xu, Yi-Zhuang; Wu, Jin-Guang

    2012-07-01

    In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use AgI fine particles as stationary phase of TLC plate. The reasons are as follows: Silver iodide fine particles have no absorbance in an IR region between 4 000 and 800 cm(-1), therefore, the interference caused by IR absorption of stationary phase can be removed. Moreover, silver iodide is stable and insolvable in water and organic solvents and thus it will not be destroyed by mobile phase or react with samples during the TLC separation. To improve TLC separation efficiency and quality of FTIR spectra during the TLC/FTIR analysis, the size of AgI particles should be below 500 nm. We used orthogonal design approach to optimize the experimental condition to AgI particles so that the average size of AgI particles is around 100 nm. No absorption of impurity or adsorbed water were observed in FTIR spectrum of the AgI particles the authors used "settlement volatilization method" to prepare TLC plate without using polymeric adhesive that may bring about significant interference in FTIR analysis. Preliminary TLC experiments proved that the TLC plate using AgI fine particles as stationary phase can separate mixtures of rhodamine B and bromophenol blue successfully. Applications of silver iodide fine particles as stationary phase have bright perspective in the development of in-situ TLC/FTIR analysis techniques.

  7. Hydrophobic aggregation of fine particles in high muddied coal slurry water.

    Science.gov (United States)

    Chen, Jun; Min, Fanfei; Liu, Lingyun; Peng, Chenliang; Lu, Fangqin

    2016-01-01

    The hydrophobic aggregation of fine particles in high muddied coal slurry water in the presence of four quaternary ammonium salts of 1231(dodecyl trimethyl ammonium chloride), 1431(tetradecyl trimethyl ammonium chloride), 1631(cetyl trimethyl ammonium chloride) and 1831(octadecyl trimethyl ammonium chloride) was investigated through the measurement of contact angles, zeta potentials, aggregation observation, adsorption and sedimentation. The results show that quaternary ammonium salts can enhance the hydrophobicity and reduce the electronegativity of particle surface, and thus induce a strong hydrophobic aggregation of slurry fine particles which promotes the settlement of coal slurry water. The adsorption of quaternary ammonium salts on slurry particles increases with the increase of alkyl chain length and reagent dosage, and will reach equilibrium when the dosage reaches a certain value. Weak alkaline conditions also can promote quaternary ammonium salts to be adsorbed on the coal slurry fine particles. In addition, reasonable energy input and a chemical environment of weak alkaline solution are conducive to hydrophobic aggregation settlement of high muddied coal slurry water with quaternary ammonium salts. The main mechanism of hydrophobic aggregation of coal slurry particles with quaternary ammonium salts is 'adsorption charge neutralization' and hydrophobic interaction.

  8. Study of nitro-polycyclic aromatic hydrocarbons in fine and coarse atmospheric particles

    Science.gov (United States)

    Teixeira, Elba Calesso; Garcia, Karine Oliveira; Meincke, Larissa; Leal, Karen Alam

    2011-08-01

    The purpose of the present study was to evaluate six nitro-polycyclic aromatic hydrocarbons (NPAHs) in fine (MAPA), RS, Brazil. The method used was of NPAHs isolation and derivatization, and subsequent gas chromatography by electron capture detection (CG/ECD). Results revealed a higher concentration of NPAHs, especially 3-nitrofluoranthene and 1-nitropyrene, in fine particles in the sampling sites studied within the MAPA. The diagnostic ratios calculated for PAHs and NPAHs identified the influence of heavy traffic, mainly of diesel emissions. The correlation of NPAHs with other pollutants (NO x, NO 2, NO and O 3) evidence the influence of vehicular emissions in the MAPA. The seasonal variation evidenced higher NPAHs concentrations in the fine particles during winter for most compounds studied.

  9. Nasal Contribution to Breathing and Fine Particle Deposition in Children Versus Adults

    Science.gov (United States)

    Both the route of breathing, nasal versus oral, and the effectiveness of the nose to filter inhaled, fine particles may differ between children and adults. This study compared (1) the nasal contribution to breathing at rest and during mild to moderate exercise in children (age 6–...

  10. Measuring the Variations of the Apparent Settling Velocity for Fine Particles

    DEFF Research Database (Denmark)

    Larsen, Torben

    2000-01-01

    This note establishes the fact that the settling velocity for fine flocculent particles in flowing aquatic systems vary considerably and the settling velocity should therefore be understood as a variable which varies temporally and spatially in the flow field. In the mathematical formulation...

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

    Directory of Open Access Journals (Sweden)

    Tianhao Zhang

    2016-08-01

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

  12. DYNAMIC RHEOLOGICAL BEHAVIOR OF POLYPROPYLENE FILLED WITH ULTRA-FINE POWDERED RUBBER PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Qiang Zheng; Yan-xia Cao; Miao Du

    2004-01-01

    Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on an Advanced Rheometric Expansion System (ARES). A specific viscoelastic phenomenon, i.e. "the second plateau", appeared at low frequencies, and exhibits a certain dependence on the amount of rubber particles and the dispersion state in the matrix. This phenomenon is attributed to the formation of aggregation structure of rubber particles. The analyses of Cole-Cole diagrams of the dynamic viscoelastic functions suggest that the heterogeneity of the composites is enhanced on increasing both particle content and temperature.

  13. Rotational particle separator: a new method for separating fine particles and mists from gases

    NARCIS (Netherlands)

    Brouwers, Bert

    1996-01-01

    An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focused on the working principle, fluid mechanical constraints, particle design, separation performance, power consumpti

  14. Drinking water biotic safety of particles and bacteria attached to fines in activated carbon process

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; LIN Tao; WANG Leilei

    2007-01-01

    In this paper,the drinking water biotic safety of particles and bacteria attached to fines in activated carbon process was investigated by actual treatment process and advanced treatment pilot trial with granular activated carbon.In the experiment,the particles were detected by IBR particle calculating instrument,the activated carbon fines were counted on the basis of the most probable number (MPN) with a microscope,the total number of bacteria was analyzed between the conventional agar culture medium and the one with R2A,and the bacteria attached to activated carbon fines was resolved by the homogenization technique.The experimental results showed that the average total number of particles was 205 CNT/mL in the activated carbon effluent during a filter cycle,of which the number of particles with sizes>2μm was 77 CNT/mL more than the present particle control criterion of the American drinking water product standard (50 CNT/mL).The backwash of low density and long duration lowered particle number in the effluent.The MPN of activated carbon frees in the effluent was between 400 and 600 CNT/L,which accounted for less than 5‰ of the total particles from activated carbon filtration for a poor relative level (R2= 0.34).The microorganisms in activated carbon effluent consisted mostly of heterotrophic bacillus and the total bacteria number was five times as high as that of the inflow,i.e.the effluent from sand filter.The actual bacteria number may be truly indicated by the detection technique with R2A culture medium compared with the traditional agar cultivation.The inactivation efficiency of bacteria attached to activated carbon fines was less than 40% under 1.1 mg/L of chlorine contacting for 40 min.Results showed that the particles and bacteria attached to activated carbon fines may influence drinking water biotic safety,and that the effective control measures need to be further investigated.

  15. Fine and Ultrafine Particles from Combustion Sources - Investigations with in-situ techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pagels, Joakim

    2005-04-01

    Fine airborne particles are associated with adverse health effects in the human population. The aim of this research was to develop and evaluate methods for in-situ characterisation of fine and ultrafine particles and to determine their deposition in the human airways. The aim was also to increase knowledge about health and environmentally relevant properties of aerosols from biomass combustion and selected indoor sources. The methods include instrumental techniques such as Scanning Mobility Particle Sizer (SMPS), Electrical Low-Pressure Impactor (ELPI), Aerodynamic Particle Sizer (APS) and Tandem Differential Mobility Analysers (TDMA) based on volatility and hygroscopic growth. Filter samplers and impactors were used for collecting particles on substrates for subsequent chemical analysis. Emissions from local district heating plants (0.5-12 MW), based on moving grate combustion of woody fuels, were sampled with a dilution system and characterised. Particles from the indoor sources of cigarettes, incense and candles were examined in the laboratory by using an airtight 22 m{sup 3} stainless steel chamber. A set-up to determine respiratory deposition in humans was constructed. It was automatised and uses an electrical mobility spectrometer with an improved inversion algorithm to perform fast measurements of particles of different sizes in the inhaled and exhaled air. It was evaluated on human test-persons. The investigated biomass combustion sources emit high concentrations of fine and ultrafine particles. The chemical composition is dominated by KCl and K{sub 2}SO{sub 4}; Zn, Cd and Pb were also quantified. Elemental carbon was identified in particles larger than 150 nm during periods of incomplete combustion. The particle concentration depends on the fuel ash content and the combustion efficiency. The aerosol is essentially internally mixed with hygroscopic growth factors significantly higher than reported for diesel exhaust and environmental tobacco smoke. The

  16. Design of sustained release fine particles using two-step mechanical powder processing: particle shape modification of drug crystals and dry particle coating with polymer nanoparticle agglomerate.

    Science.gov (United States)

    Kondo, Keita; Ito, Natsuki; Niwa, Toshiyuki; Danjo, Kazumi

    2013-09-10

    We attempted to prepare sustained release fine particles using a two-step mechanical powder processing method; particle-shape modification and dry particle coating. First, particle shape of bulk drug was modified by mechanical treatment to yield drug crystals suitable for the coating process. Drug crystals became more rounded with increasing rotation speed, which demonstrates that powerful mechanical stress yields spherical drug crystals with narrow size distribution. This process is the result of destruction, granulation and refinement of drug crystals. Second, the modified drug particles and polymer coating powder were mechanically treated to prepare composite particles. Polymer nanoparticle agglomerate obtained by drying poly(meth)acrylate aqueous dispersion was used as a coating powder. The porous nanoparticle agglomerate has superior coating performance, because it is completely deagglomerated under mechanical stress to form fine fragments that act as guest particles. As a result, spherical drug crystals treated with porous agglomerate were effectively coated by poly(meth)acrylate powder, showing sustained release after curing. From these findings, particle-shape modification of drug crystals and dry particle coating with nanoparticle agglomerate using a mechanical powder processor is expected as an innovative technique for preparing controlled-release coated particles having high drug content and size smaller than 100 μm.

  17. Formation of Splats from Suspension Particles with Solid Inclusions Finely Dispersed in a Melted Metal Matrix

    Science.gov (United States)

    Solonenko, O. P.

    2012-12-01

    A theoretical model has been developed to describe the splats formation from composite particles of several tens of micrometers in size whose liquid metal binder contains a high volume concentration of ultra-fine refractory solid inclusions uniformly distributed in the binder. A theoretical solution was derived, enabling evaluation of splat thickness and diameter, and also the contact temperature at the particle-substrate interface, under complete control of key physical parameters (KPPs) of the spray process (impact velocity, temperature, and size of the particle, and substrate temperature) versus the concentration of solid inclusions suspended in the metal-binder melt. Using the solution obtained, the calculations performed demonstrate the possibility of formulating adequate requirements on the KPPs of particle-substrate interaction providing a deposition of ceramic-metal coatings with predictable splat thickness and degree of particle flattening on the substrate, and also with desired contact temperature during the formation of the first coating monolayer.

  18. Low-velocity pneumatic conveying in horizontal pipe for coarse particles and fine powders

    Institute of Scientific and Technical Information of China (English)

    Yuji Tomita; Vijay Kumar Agarwal; Hiroyuki Asou; Katsuya Funatsu

    2008-01-01

    First,the characteristics of low-velocity conveying of particles having different hardness are experimentally investigated in a horizontal pipeline in terms of flow pattern and pressure drop to show that the slug flow can be classified into two types depending on the settling of particles along the pipeline,and the period is small for slug flow without the settled layer,which is called solitary slug flow.The pressure drop for soft particles is shown to be larger than that for hard particles.Then,experimental results are presented on horizontal fluidized-bed conveying of fine powders to show that air release from the top surface of the conveying channel is an important factor for high mass flow rate of particles.

  19. A novel permanently magnetised high gradient magnetic filter using assisted capture for fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.H.P. [Univ. of Southampton (United Kingdom)

    1995-02-01

    This paper describes the structure and properties of a novel permanently magnetised magnetic filter for fine friable radioactive material. Previously a filter was described and tested. This filter was designed so that the holes in the filter are left open as capture proceeds which means the pressure drop builds up only slowly. This filter is not suitable for friable composite particles which can be broken by mechanical forces. The structure of magnetic part of the second filter has been changed so as to strongly capture particles composed of fine particles weakly bound together which tend to break when captured. This uses a principle of assisted-capture in which coarse particles aid the capture of the fine fragments. The technique has the unfortunate consequence that the pressure drop across the filter rises faster as capture capture proceeds than the filter described previously. These filters have the following characteristics: (1) No external magnet is required. (2) No external power is required. (3) Small is size and portable. (4) Easily interchangeable. (5) Can be cleaned without demagnetising.

  20. The cumulative effects of using fine particles and cyanobacteria for rehabilitation of disturbed active sand dunes

    Science.gov (United States)

    Zaady, Eli; Katra, Itzhak; Barkai, Daniel; Knoll, Yaakov; Sarig, Shlomo

    2016-04-01

    One of the main problems in desertified lands worldwide is active wind-borne sand dunes, which lead to covering of fertile soils and agricultural fields. In regions with more than 100 mm of annual rainfall, sand dunes may be naturally stabilized by biocrusts (biological soil crusts). One of the main restraints of biocrust development is the typical lack of fine particles in sand dunes. Our study investigated the combined application of fine particles [coal fly-ash <100 micrometer] and bio-inoculant of filamentous cyanobacteria, isolated from nearby natural stabilized sand dunes, on the soil surface of active sands for increasing resistance to wind erosion. Boundary-layer wind tunnel experiments were conducted in experimental plots within a greenhouse for examining the effects of adding coal fly-ash and bio-inoculant to active sands. The biocrust development was evaluated via several physical and bio-physiological variables. In all the physical measurements and the bio-physiological variables, the treatment of "sand+inoculum+coal fly-ash" showed significant differences from the "sand-control". The combination led to the best results of surface stabilization in boundary-layer wind tunnel experiments, with the lowest sand fluxes. The filamentous cyanobacteria use the fine particles of the coal fly-ash as bridges for growing toward and adhering to the large sand particles. The cumulative effects of biocrusts and coal fly-ash enhance soil surface stabilization and may allow long-term sustainability.

  1. Influence of rain on the abundance of bioaerosols in fine and coarse particles

    Science.gov (United States)

    Rathnayake, Chathurika M.; Metwali, Nervana; Jayarathne, Thilina; Kettler, Josh; Huang, Yuefan; Thorne, Peter S.; O'Shaughnessy, Patrick T.; Stone, Elizabeth A.

    2017-02-01

    Assessing the environmental, health, and climate impacts of bioaerosols requires knowledge of their size and abundance. These two properties were assessed through daily measurements of chemical tracers for pollens (sucrose, fructose, and glucose), fungal spores (mannitol and glucans), and Gram-negative bacterial endotoxins in two particulate matter (PM) size modes: fine particles ( 75 %), as expected for particles greater than 2.5 µm. Rainfall on 2 May corresponded to maximum atmospheric pollen tracer levels and a redistribution of pollen tracers to the fine PM fraction (> 80 %). Both changes were attributed to the osmotic rupture of pollen grains that led to the suspension of fine-sized pollen fragments. Fungal spore tracers peaked in concentration following spring rain events and decreased in particle size, but to a lesser extent than pollens. A short, heavy thunderstorm in late summer corresponded to an increase in endotoxin and glucose levels, with a simultaneous shift to smaller particle sizes. Simultaneous increase in bioaerosol levels and decrease in their size have significant implications for population exposures to bioaerosols, particularly during rain events. Chemical mass balance (CMB) source apportionment modeling and regionally specific pollen profiles were used to apportion PM mass to pollens and fungal spores. Springtime pollen contributions to the mass of particles < 10 µm (PM10) ranged from 0.04 to 0.8 µg m-3 (0.2-38 %, averaging 4 %), with maxima occurring on rainy days. Fungal spore contributions to PM10 mass ranged from 0.1 to 1.5 µg m-3 (0.8-17 %, averaging 5 %), with maxima occurring after rain. Overall, this study defines changes to the fine- and coarse-mode distribution of PM, pollens, fungal spores, and endotoxins in response to rain in the Midwestern United States and advances the ability to apportion PM mass to pollens.

  2. Mercury speciation and fine particle size distribution on combustion of Chinese coals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; Wang, Shuxiao; Hao, Jiming [Tsinghua Univ., Beijing (China). Dept. of Environmental Science and Engineering and State Key Joint Lab. of Environment Simulation and Pollution Control; Daukoru, Michael; Torkamani, Sarah; Biswas, Pratim [Washington Univ., St. Louis, MO (United States). Aerosol and Air Quality Research Lab.

    2013-07-01

    Coal combustion is the dominant anthropogenic mercury emission source of the world. Electrostatic precipitator (ESP) can remove almost all the particulate mercury (Hg{sub p}), and wet flue gas desulfurization (WFGD) can retain a large part of the gaseous oxidized mercury (Hg{sup 2+}). Only a small percentage of gaseous elemental mercury (Hg{sup 0}) can be abated by the air pollution control devices (APCDs). Therefore, the mercury behavior across APCDs largely depends on the mercury speciation in the flue gas exhausting from the coal combustor. To better understand the formation process of three mercury species, i.e. Hg{sup 0}, Hg{sup 2+} and Hg{sub p}, in gaseous phase and fine particles, bench-scale measurements for the flue gas exhausting from combustion of different types of coal in a drop-tube furnace set-up, were carried out. It was observed that with the limitation of reaction kinetics, higher mercury concentration in flue gas will lead to lower Hg{sup 2+} proportion. The concentration of chlorine has the opposite effect, not as significantly as that of mercury though. With the chlorine concentration increasing, the proportion of Hg{sup 2+} increases. Combusting the finer coal powder results in the formation of more Hg{sup 2+}. Mineral composition of coal and coal particle size has a great impact on fine particle formation. Al in coal is in favor of finer particle formation, while Fe in coal can benefit the formation of larger particles. The coexistence of Al and Si can strengthen the particle coagulation process. This process can also be improved by the feeding of more or finer coal powder. The oxy-coal condition can make for both the mercury oxidation process and the metal oxidation in the fine particle formation process.

  3. Restraint of fatigue crack growth by wedge effects of fine particles

    CERN Document Server

    Takahashi, I; Kotani, N

    2000-01-01

    Presents some experimental results which demonstrate restraint of fatigue crack growth in an Al-Mg alloy by wedge effects of fine particles. Fatigue test specimens were machined from a JIS A5083P-O Al-Mg alloy plate of 5 mm thickness and an EDM starter notch was introduced to each specimen. Three kinds of fine particles were prepared as the materials to be wedged into the fatigue cracks, i.e. magnetic particles and two kinds of alumina particles having different mean particle sizes of 47.3 mu m and 15.2 mu m. Particles of each kind were suspended in an oil to form a paste, which was applied on the specimen surface covering the notch zone prior to the fatigue tests. In order to make some fracture mechanics approaches, in situ observations of fatigue cracks were performed for the two cases using a CCD microscope, with a magnification of *1000. The crack length and the crack opening displacement (COD) at the notch root, delta , were measured. The crack retardation effect continues almost through the entire lifet...

  4. [Using barium fluoride fine particles as stationary phase for TLC/FTIR analysis].

    Science.gov (United States)

    Liu, Xi; Pan, Qing-hua; Ding, Jie; Zhu, Qing; He, An-qi; Yue, Shi-juan; Li, Xiao-pei; Hu, Li-ping; Xia, Jin-ming; Liu, Cui-ge; Wei, Yong-ju; Yu, Jiang; Yang, Zhan-lan; Zhu, Xi; Xu, Yi-zhuang; Wu, Jin-guang

    2011-07-01

    In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase such as silica gel etc. has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use barium fluoride fine particles as stationary phase of TLC plate. The reasons are as follows: Barium fluoride wafer has been extensively used as infrared window in FTIR experiments and it has no absorbance in an IR region between 4 000 and 800 cm'. As a matter of fact, the atomic mass of barium and fluoride is quite large, thus the normal vibration of BaF2 lattice is limited in far-IR region and low frequency part of mid-IR region. Therefore, the interference caused by IR absorption of stationary phase can be resolved if BaF2 is used as stationary phase of TLC plate. Moreover, BaF2 is quite stable and insolvable in water and most organic solvents and it will not be dissolved by mobile phase or react with samples in TLC separation. Additionally, decreasing the particle size of BaF2 is very important in TLC/FTIR analysis technique. The reason is two-fold: First, decreasing the particle size of stationary phase is helpful to improving the efficiency of separation by TLC plate; second, decreasing the size of BaFz particle can improve the quality of FTIR spectra by alleviating the problem of light scattering. By optimizing the synthetic conditions, fine particles of barium fluoride were obtained. SEM results indicate that the size of the BaF2 particles is around 500 nm. FTIR spectrum of the BaF2 particles shows that no absorption of impurity was observed. Moreover, the elevation of baseline caused by light scattering is insignificant. The authors have developed a new technique named "settlement volatilization method" to prepare TLC plate without polymeric adhesive that may bring about significant

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

    Science.gov (United States)

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

    2016-11-15

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

  6. Association between the concentration of fine particles in the atmosphere and acute respiratory diseases in children

    Directory of Open Access Journals (Sweden)

    Antônio Paula Nascimento

    Full Text Available ABSTRACT OBJECTIVE To analyze the association between fine particulate matter concentration in the atmosphere and hospital care by acute respiratory diseases in children. METHODS Ecological study, carried out in the region of Grande Vitória, Espírito Santo, in the winter (June 21 to September 21, 2013 and summer (December 21, 2013 to March 19, 2014. We assessed data of daily count for outpatient care and hospitalization by respiratory diseases (ICD-10 in children from zero to 12 years in three hospitals in the Region of Grande Vitória. For collecting fine particulate matter, we used portable samplers of particles installed in six locations in the studied region. The Generalized Additive Model with Poisson distribution, fitted for the effects of predictor covariates, was used to evaluate the relationship between respiratory outcomes and concentration of fine particulate matter. RESULTS The increase of 4.2 µg/m3 (interquartile range in the concentration of fine particulate matter increased in 3.8% and 5.6% the risk of medical care or hospitalization, respectively, on the same day and with six-day lag from the exposure. CONCLUSIONS We identified positive association between outpatient care and hospitalizations of children under 12 years due to acute respiratory diseases and the concentration of fine particulate matter in the atmosphere.

  7. Properties of CuCr contact materials with low chromium content and fine particles

    Institute of Scientific and Technical Information of China (English)

    曹辉; 王亚平; 郑志; 冼爱平

    2003-01-01

    The voltage withstanding capability and electric conductivity of CuCr contact materials with low chromium content and fine Cr particles were studied. The results show that the withstanding voltage has little relation with the Cr content for the melted-casting CuCr alloy within 15%-29% Cr content, and that the electric conductivity of the alloy increases with the decreasing of Cr content.

  8. Fine particle mass from the Diskus inhaler and Turbuhaler inhaler in children with asthma

    DEFF Research Database (Denmark)

    Bisgaard, H; Klug, B; Sumby, B S;

    1998-01-01

    The study aimed to investigate dose consistency and particle distribution from the dry powder inhalers Diskus and Turbuhaler. Full profiles of inhalation pressure versus time were recorded in 18 4 yr old and 18 8 yr old asthmatic children through Diskus and Turbuhaler inhalers. These data were used...... is a determinant of the quality of the aerosol. The mean (SD) amount of drug in large particles (>4.7 microm), fine particles (children and 71 (3), 18 (2) and 2...... (1) from the 8 yr old children, respectively. Similar particle fractions from the Budesonide Turbuhaler were 35 (9), 21 (10) and 7 (5) from 4 yr old children and 30 (7), 32 (9) and 12 (6) from 8 yr old children. In conclusion, the Diskus inhaler provides an improved dose consistency through...

  9. The PM2.5 Fine Particle Background Network of the German Meteorological Service-First Results

    Directory of Open Access Journals (Sweden)

    Uwe Kaminski

    2013-04-01

    Full Text Available Since 2009, the measurement of the background concentration of the fine particle fraction has been a part of the climate-monitoring program of the German Meteorological Service (DWD. These particles are of high health relevance as a critical air pollutant affecting processes like the scattering and absorption of solar radiation and influencing cloud formation and visibility. At 12 weather stations, the coarse (2.5 to 10 l m and the fine particle fractions (PM2.5 are measured by means of passive and active samplers. First results are presented for the mass concentrations of coarse and fine particles as well as for the black carbon (BC content and the concentration of certain inorganic ions of fine particles. There is not only a seasonal correlation between the fraction of fine and coarse particles, but also a correlation with the location (urban background or rural background. With the help of light microscopy, coarse particles can be differentiated for a geogenic (predominantly wind blown mineral and sea salt particles of natural origin and road abrasion and for an anthropogenic opaque component (combustion residues, e.g. fly ash and non-exhaust vehicle emissions, e.g. abrasion particles of brakes and tires. Measuring the fine fraction and the coarse fraction separately instead of PM10 allows for a better source allocation and thus is a more appropriate method for the improvement of the air quality in, e.g. low emission zones.

  10. The PM{sub 2.5} fine particle background network of the German Meteorological Service. First results

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Uwe; Fricker, Mathieu; Dietze, Volker [German Meteorological Service (DWD), Freiburg im Breisgau (Germany). Air Quality Dept.

    2013-04-15

    Since 2009, the measurement of the background concentration of the fine particle fraction has been a part of the climate-monitoring program of the German Meteorological Service (DWD). These particles are of high health relevance as a critical air pollutant affecting processes like the scattering and absorption of solar radiation and influencing cloud formation and visibility. At 12 weather stations, the coarse (2.5 to 10 l m) and the fine particle fractions (PM{sub 2.5}) are measured by means of passive and active samplers. First results are presented for the mass concentrations of coarse and fine particles as well as for the black carbon (BC) content and the concentration of certain inorganic ions of fine particles. There is not only a seasonal correlation between the fraction of fine and coarse particles, but also a correlation with the location (urban background or rural background). With the help of light microscopy, coarse particles can be differentiated for a geogenic (predominantly wind blown mineral and sea salt particles of natural origin and road abrasion) and for an anthropogenic opaque component (combustion residues, e.g. fly ash and non-exhaust vehicle emissions, e.g. abrasion particles of brakes and tires). Measuring the fine fraction and the coarse fraction separately instead of PM{sub 10} allows for a better source allocation and thus is a more appropriate method for the improvement of the air quality in, e.g. low emission zones. (orig.)

  11. Optimize Operating Conditions on Fine Particle Grinding Process with Vertically Stirred Media Mill

    Science.gov (United States)

    Yang, Yang; Rowson, Neil; Ingram, Andy

    2016-11-01

    Stirred media mill recently is commonly utilized among mining process due to its high stressing intensity and efficiency. However, the relationship between size reduction and flow pattern within the mixing pot is still not fully understand. Thus, this work investigates fine particle grinding process within vertically stirred media mills by altering stirrer geometry, tip speed and solids loading. Positron Emitting Particle Tracking (PEPT) technology is utilized to plot routine of particles velocity map. By tacking trajectory of a single particle movement within the mixing vessel, the overall flow pattern is possible to be plotted. Ground calcium carbonate, a main product of Imerys, is chosen as feeding material (feed size D80 30um) mixed with water to form high viscous suspension. To obtain fine size product (normally D80 approximately 2um), large amount of energy is drawn by grinding mill to break particles through impact, shear attrition or compression or a combination of them. The results indicate higher energy efficient is obtained with more dilute suspension. The optimized stirrer proves more energy-saving performance by altering the slurry circulate. Imerys Minerals Limited.

  12. Surface area, porosity and water adsorption properties of fine volcanic ash particles

    Science.gov (United States)

    Delmelle, Pierre; Villiéras, Frédéric; Pelletier, Manuel

    2005-02-01

    Our understanding on how ash particles in volcanic plumes react with coexisting gases and aerosols is still rudimentary, despite the importance of these reactions in influencing the chemistry and dynamics of a plume. In this study, six samples of fine ash (500 Å. All the specimens had similar pore size distributions, with a small peak centered around 50 Å. These findings suggest that fine ash particles have relatively undifferentiated surface textures, irrespective of the chemical composition and eruption type. Adsorption isotherms for water vapour revealed that the capacity of the ash samples for water adsorption is systematically larger than predicted from the nitrogen adsorption as values. Enhanced reactivity of the ash surface towards water may result from (i) hydration of bulk ash constituents; (ii) hydration of surface compounds; and/or (iii) hydroxylation of the surface of the ash. The later mechanism may lead to irreversible retention of water. Based on these experiments, we predict that volcanic ash is covered by a complete monolayer of water under ambient atmospheric conditions. In addition, capillary condensation within ash pores should allow for deposition of condensed water on to ash particles before water reaches saturation in the plume. The total mass of water vapour retained by 1 g of fine ash at 0.95 relative water vapour pressure is calculated to be ~10-2 g. Some volcanic implications of this study are discussed.

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

    Science.gov (United States)

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

    2015-03-01

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

  14. Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

    Science.gov (United States)

    Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

    1996-08-01

    An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that

  15. Temporal variation of fine particle mass at two sites in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, P.; Allen, G. [Harvard School of Public Health, Boston, MA (United States); Castillejos, M. [Univ. Autonoma Metropolitana, Xochimilco (Mexico); Gold, D.; Speizer, F. [Brigham and Women`s Hospital, Boston, MA (United States); Hernandez, M. [Inst. Nacional de Salud Publica, Cuernavaca (Mexico); Hayes, C.; McDonnell, W. [Environmental Protection Agency, Research Triangle Park, NC (United States)

    1994-12-31

    Simultaneous sampling of fine mass (PM{sub 2.5}, using an integrated 24 hour gravimetric method) and the particle scattering extinction coefficient (b{sub sp}, using a heated integrating nephelometer) were used to estimate continuous fine particle concentration at two sites in Mexico City. Linear regression analysis of the 24 h averages of b{sub sp} and the PM{sub 2.5} integrated samples was done on a seasonal basis. The coefficients of determination (R{sup 2}) between these methods ranged from 0.84 to 0.90 for the different sampling periods. These data are the first attempt to describe the diurnal variation of fine mass in Mexico City. Distinct and different diurnal patterns were observed for both sites. For the site located near an industrialized area, a sharp peak occurred between 0700 and 0900 hours and a second smaller but broader peak occurred late at night. This site is characterized by the presence of primary pollutants, with PM{sub 10} annual mean concentrations exceeding 150 {micro}g {center_dot} m{sup {minus}3}. The second bite is located in a residential area down wind of the industrialized area, and is characterized by the presence of secondary pollutants with much lower PM{sub 10} concentrations (annual mean of under 50 {micro}g {center_dot} m{sup {minus}3}). The diurnal fine mass pattern at this site had a broad peak between 0900 and 1200 hours. On individual days, fine mass was sometimes highly correlated with ozone.

  16. Physicochemical characterization of fine particles from small-scale wood combustion

    Science.gov (United States)

    Lamberg, Heikki; Nuutinen, Kati; Tissari, Jarkko; Ruusunen, Jarno; Yli-Pirilä, Pasi; Sippula, Olli; Tapanainen, Maija; Jalava, Pasi; Makkonen, Ulla; Teinilä, Kimmo; Saarnio, Karri; Hillamo, Risto; Hirvonen, Maija-Riitta; Jokiniemi, Jorma

    2011-12-01

    Emissions from small-scale wood combustion appliances are of special interest since fine particles have been consistently associated with adverse health effects. It has been reported that the physicochemical characteristics of the emitted particles affect also their toxic properties but the mechanisms behind these phenomena and the causative role of particles from wood combustion sources are still mostly unknown. Combustion situations vary significantly in small-scale appliances, especially in batch combustion. Combustion behaviour is affected by fuel properties, appliance type and operational practice. Particle samples were collected from six appliances representing different combustion situations in small-scale combustion. These appliances were five wood log fuelled stoves, including one stove equipped with modern combustion technology, three different conventional combustion appliances and one sauna stove. In addition, a modern small-scale pellet boiler represented advanced continuous combustion technology. The aim of the study was to analyze gas composition and fine particle properties over different combustion situations. Fine particle (PM 1) emissions and their chemical constituents emerging from different combustion situations were compared and this physicochemical data was combined with the toxicological data on cellular responses induced by the same particles (see Tapanainen et al., 2011). There were significant differences in the particle emissions from different combustion situations. Overall, the efficient combustion in the pellet boiler produced the smallest emissions whereas inefficient batch combustion in a sauna stove created the largest emissions. Improved batch combustion with air-staging produced about 2.5-fold PM 1 emissions compared to the modern pellet boiler (50.7 mg MJ -1 and 19.7 mg MJ -1, respectively), but the difference in the total particulate PAH content was 750-fold (90 μg MJ -1 and 0.12 μg MJ -1, respectively). Improved batch

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

    Science.gov (United States)

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

    2004-09-01

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

  18. Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, M.; Lee, H.J.; Shim, Y. [Korean Mine Reclamation Corporation MIRECO, Seoul (Republic of Korea)

    2010-07-01

    The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 {mu} m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L{sup -1} FL-2949 (coagulant) and 12 mg L{sup -1} A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

  19. Mineralogical properties and internal structures of individual fine particles of Saharan dust

    Science.gov (United States)

    Jeong, Gi Young; Park, Mi Yeon; Kandler, Konrad; Nousiainen, Timo; Kemppinen, Osku

    2016-10-01

    Mineral dust interacts with incoming/outgoing radiation, gases, other aerosols, and clouds. The assessment of its optical and chemical impacts requires knowledge of the physical and chemical properties of bulk dust and single particles. Despite the existence of a large body of data from field measurements and laboratory analyses, the internal properties of single dust particles have not been defined precisely. Here, we report on the mineralogical organization and internal structures of individual fine ( common particle type was clay-rich agglomerate, dominated by illite-smectite series clay minerals with subordinate kaolinite. Submicron grains of iron (hydr)oxides (goethite and hematite) were commonly dispersed through the clay-rich particles. The median total volume of the iron (hydr)oxide grains included in the dust particles was estimated to be about 1.5 % vol. The average iron content of clay minerals, assuming 14 wt % H2O, was determined to be 5.0 wt %. Coarse mineral cores, several micrometers in size, were coated with thin layers of clay-rich agglomerate. Overall, the dust particles were roughly ellipsoidal, with an average axial ratio of 1.4 : 1.0 : 0.5. The mineralogical and structural properties of single Saharan dust particles provide a basis for the modeling of dust radiative properties. Major iron-bearing minerals, such as illite-smectite series clay minerals and iron (hydr)oxides, were commonly submicron- to nano-sized, possibly enhancing their biogeochemical availability to remote marine ecosystems lacking micronutrients.

  20. Benthic biofilm structure controls the deposition-resuspension dynamics of fine clay particles

    Science.gov (United States)

    Hunter, W. R.; Roche, K. R.; Drummond, J. D.; Boano, F.; Packman, A. I.; Battin, T. J.

    2015-12-01

    In fluvial ecosystems the alternation of deposition and resuspension of particles represents an important pathway for the downstream translocation of microbes and organic matter. Such particles can originate from algae and microbes, the spontaneous auto-aggregation of organic macromolecules (e.g., "river sown"), terrestrial detritus (traditionally classified as "particulate organic matter"), and erosive mineral and organo-mineral particles. The transport and retention of particles in headwater streams is associated with biofilms, which are surface-attached microbial communities. Whilst biofilm-particle interactions have been studied in bulk, a mechanistic understanding of these processes is lacking. Parallel macroscale/microscale observations are required to unravel the complex feedbacks between biofilm structure, coverage and the dynamics of deposition and resuspension. We used recirculating flume mesocosms to test how changes in biofilm structure affected the deposition and resuspension of clay-sized (< 10 μm) particles. Biofilms were grown in replicate 3-m-long recirculating flumes over variable lengths of time (0, 14, 21, 28, and 35) days. Fixed doses of fluorescent clay-sized particles were introduced to each flume and their deposition was traced over 30 minutes. A flood event was then simulated via a step increase in flowrate to quantify particle resuspension. 3D Optical Coherence Tomography was used to determine roughness, areal coverage and height of biofilms in each flume. From these measurements we characterised particle deposition and resuspension rates, using continuous time random walk modelling techniques, which we then tested as responses to changes in biofilm coverage and structure under both base-flow and flood-flow scenarios. Our results suggest that biofilm structural complexity is a primary control upon the retention and downstream transport of fine particles in stream mesocosms.

  1. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    Directory of Open Access Journals (Sweden)

    Nanbu H.

    2010-06-01

    Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  2. High temperature oxidation event of gelatin nanoskin-coated copper fine particles observed by in situ TEM

    Directory of Open Access Journals (Sweden)

    Takashi Narushima

    2012-12-01

    Full Text Available Metallic copper fine particles were prepared using CuO slurry by hydrazine reduction in the presence of gelatin. To observe a behavior of these particles at high temperature, in situ heating TEM observations were carried out. Oxygen gas was introduced and the pressure of the TEM column was kept at 10−3 Pa, corresponding the pressure around the sample at 10−1 Pa. The gelatin, which acts as a protective nanoskin on the particle surface was gradually decomposed. Around approximately 140 °C, it was observed that Cu2O dots formed on the surface of the copper particle. This result is well consistent with the behavior of the TG-DTA curve of the copper fine particles under ambient conditions, and provides key information of oxidative behavior of copper fine particles.

  3. Teaching Particle Physics in the Open University's Science Foundation Course.

    Science.gov (United States)

    Farmelo, Graham

    1992-01-01

    Discusses four topics presented in the science foundation course of the Open University that exemplify current developments in particle physics, in particular, and that describe important issues about the nature of science, in general. Topics include the omega minus particle, the diversity of quarks, the heavy lepton, and the discovery of the W…

  4. Highly time-resolved chemical characterization of atmospheric fine particles during 2010 Shanghai World Expo

    Directory of Open Access Journals (Sweden)

    X.-F. Huang

    2012-06-01

    Full Text Available Shanghai, with a population of over 20 million, is the largest mega-city in China. Rapidly increasing industrial and metropolitan emissions have deteriorated its air quality in the past decades, with fine particle pollution as one of the major issues. However, systematic characterization of atmospheric fine particles with advanced measurement techniques has been very scarce in Shanghai. During 2010 Shanghai World Expo, we deployed a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a single particle soot photometer (SP2 in urban Shanghai between 15 May and 10 June 2010 to measure fine particles with a high time resolution. The 4-min resolution PM1 mass concentration ranged from 5.5 to 155 μg m−3, with an average of 29.2 μg m−3. On average, sulfate and organic matter (OM were the most abundant PM1 components, accounting for 33.3 and 28.7% of the total mass, respectively, while the fraction of nitrate showed an increasing trend with the increasing PM1 loading, indicating the photochemical nature of high fine particle pollution in Shanghai. Taking advantage of HR-ToF-AMS and SP2, OM was found to have an average OM/OC ratio (organic matter mass/organic carbon mass of 1.55 and black carbon (BC had an average number fraction of internally mixed BC of 41.2%. Positive matrix factorization (PMF analysis on the high resolution organic mass spectral dataset identified a hydrocarbon-like (HOA, a semi-volatile oxygenated (SV-OOA, and a low-volatility oxygenated (LV-OOA organic aerosol component, which on average accounted for 24.0, 46.8, and 29.2% of the total organic mass, respectively. The diurnal patterns of them with interesting time delay possibly implied a photochemical oxidizing process from HOA (and/or its concurrently emitted gaseous organic pollutants to SV-OOA to LV-OOA. Back trajectory analysis indicated that the northwesterly continental air mass represented the

  5. Highly time-resolved chemical characterization of atmospheric fine particles during 2010 Shanghai World Expo

    Directory of Open Access Journals (Sweden)

    X.-F. Huang

    2012-01-01

    Full Text Available Shanghai, with a population of over 20 million, is the largest mega-city in China. Rapidly increasing industrial and metropolitan emissions have deteriorated its air quality in the past decades, with fine particle pollution as one of the major issues. However, systematic characterization of atmospheric fine particles with advanced measurement techniques has been very scarce in Shanghai. During 2010 Shanghai World Expo, we deployed a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a single particle soot photometer (SP2 in urban Shanghai between 15 May and 10 June 2010 to measure fine particles with a high time resolution. The 4-min resolution PM1 mass concentration ranged from 5.5 to 155 μg m−3, with an average of 29.2 μg m−3. On average, sulfate and organic matter (OM were the most abundant PM1 components, accounting for 33.3 and 28.7% of the total mass, respectively, while the fraction of nitrate showed an increasing trend with the increasing PM1 loading, indicating the photochemical nature of high fine particle pollution in Shanghai. Taking advantage of HR-ToF-AMS and SP2, OM was found to have an average OM/OC ratio (organic matter mass/organic carbon mass of 1.55 and black carbon (BC had an average number fraction of internally mixed BC of 41.2%. Positive matrix factorization (PMF analysis on the high resolution organic mass spectral dataset identified a hydrocarbon-like (HOA, a semi-volatile oxygenated (SV-OOA, and a low-volatility oxygenated (LV-OOA organic aerosol component, which on average accounted for 24.0, 46.8, and 29.2% of the total organic mass, respectively. The diurnal patterns of them with interesting time delay possibly implied a photochemical oxidizing process from HOA (and/or its concurrently emitted gaseous organic pollutants to SV-OOA to LV-OOA. Back trajectory analysis indicated that the northwesterly continental air mass represented the

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

    Science.gov (United States)

    Azarmi, Farhad; Kumar, Prashant

    2016-07-01

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

  7. Preparation of semi-solid slurry containing fine and globular particles for wrought aluminum alloy 2024

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The semi-solid slurry of wrought aluminum alloy 2024 was prepared by a well developed rheocasting process, low superheat pouring with shearing field(LSPSF). The appreciate combination of pouring temperature and rotation speed of barrel, can give rise to a transition of the growth morphology of primary α(Al) from coarse-dendritic to coarse-particle-like and further to fine-globular. The combined effects of both localized rapid cooling and vigorous mixing during the initial stage of solidification can enhance wall nucleation and nuclei survival, which leads to the formation of fine-globular primary α(Al). By using semi-solid slurry prepared by LSPSF, direct squeeze cast cup-shaped component with improved mechanical properties such as yield strength of 198MPa, ultimate tensile strength of 306 MPa and elongation of 10.4%, can be obtained.

  8. Metal-bearing fine particle sources in a coastal industrialized environment

    Science.gov (United States)

    Mbengue, Saliou; Alleman, Laurent Y.; Flament, Pascal

    2017-01-01

    Fine (primary or secondary submicron particles and mechanical procedures in open air, or local traffic, which lead to the emission of coarser particles (> 1 μm). The trace elements As, Cd, Ni, Pb, Sb, V and Zn, characteristics of the local industrial activities display 60% to 85% of their mass in the submicron and ultrafine fractions and appear highly enriched, by reference to the crustal source. High atmospheric pressure periods, corresponding to northeasterly winds, induce the highest contributions of metalworking emissions and the highest PM2.5 concentrations (32.5 ± 11.9 μg·m- 3). A Principal Component Analysis of the dataset produces 7 factors associated to metallurgy-, steelworks-, oil processing-, coal combustion-, neighboring traffic-, dust resuspension- and sea salt-sources, that explain the obtained concentrations. A Multiple Linear Regression Analysis confirms that Fe-Mn alloy refining, iron- and steel-making are the main sources (> 40%) controlling metal concentrations in PM2.5. Less predictably, resuspended dust and fresh/aged sea salts are also significant contributors (≈ 20%). Considering the related health hazards, authorities should pay more attention to the exposure of people living in this area and the possible impact of fine particles in terms of public health.

  9. Inflight Performance of the SDO Fine Pointing Science Mode

    Science.gov (United States)

    Mason, Paul; O'Donnell, James; Starin, Scott R.; Halverson, Julie; Vess, Melissa F.

    2017-01-01

    The Solar Dynamics Observatory (SDO) was successfully launched and deployed from its Atlas V launch vehicle on February 11, 2010. Three months later, on May 14, 2010, the fully commissioned heliophysics laboratory was handed over to Space Systems Mission Operations to begin its science mission. SDO is an Explorer-class mission now operating in a geosynchronous orbit, sending data 24 hours per day to a dedicated ground station in White Sands, New Mexico. It carries a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly (AIA) includes four telescopes with 4096x4096 focal plane CCDs that can image the full solar disk in seven extreme ultraviolet and three ultraviolet-visible wavelengths. The Extreme Ultraviolet Variability Experiment (EVE) collects time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager (HMI) enables study of pressure waves moving through the body of the Sun.

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

    Directory of Open Access Journals (Sweden)

    M. R. Perrone

    2014-08-01

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

  11. Solution of population balance equations in applications with fine particles: Mathematical modeling and numerical schemes

    Science.gov (United States)

    Nguyen, T. T.; Laurent, F.; Fox, R. O.; Massot, M.

    2016-11-01

    The accurate description and robust simulation, at relatively low cost, of global quantities (e.g. number density or volume fraction) as well as the size distribution of a population of fine particles in a carrier fluid is still a major challenge for many applications. For this purpose, two types of methods are investigated for solving the population balance equation with aggregation, continuous particle size change (growth and size reduction), and nucleation: the extended quadrature method of moments (EQMOM) based on the work of Yuan et al. [52] and a hybrid method (TSM) between the sectional and moment methods, considering two moments per section based on the work of Laurent et al. [30]. For both methods, the closure employs a continuous reconstruction of the number density function of the particles from its moments, thus allowing evaluation of all the unclosed terms in the moment equations, including the negative flux due to the disappearance of particles. Here, new robust and efficient algorithms are developed for this reconstruction step and two kinds of reconstruction are tested for each method. Moreover, robust and accurate numerical methods are developed, ensuring the realizability of the moments. The robustness is ensured with efficient and tractable algorithms despite the numerous couplings and various algebraic constraints thanks to a tailored overall strategy. EQMOM and TSM are compared to a sectional method for various simple but relevant test cases, showing their ability to describe accurately the fine-particle population with a much lower number of variables. These results demonstrate the efficiency of the modeling and numerical choices, and their potential for the simulation of real-world applications.

  12. Modeling the injection of gas-liquid jets into fluidized bed of fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Aryiapadi, S.; Berutti, F.; Briens, C.; Hulet, C. [Western Ontario University, Dept. of Chemical and Biochemical Engineeering, London, ON (Canada); Griffith, P. [Massachussetts Institute of Technology, Dept. of Mechanical Engineering, Cambridge, MA (United States)

    2003-08-01

    A simplified momentum-based approach to calculate the solid entrainment rate into a gas-liquid jet injected into a fluidized bed is described. The model is verified by a recently developed experimental technique. The paper also addresses correction factors to the initial momentum calculated from the homogenous model. The solids entrainment rates predicted by the model were found to be very close to experimentally obtained values. It is suggested that the model can be usefully employed in characterizing the behaviour of gas-liquid jets injected into fluidized beds of fine particles. 21 refs., 8 figs.

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

    Science.gov (United States)

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

    2016-04-01

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

  14. Decreases in elemental carbon and fine particle mass in the United States

    Directory of Open Access Journals (Sweden)

    D. M. Murphy

    2011-01-01

    Full Text Available Observations at national parks and other remote sites show that average elemental carbon and fine particle mass concentrations in the United States both decreased by over 25% between 1990 and 2004. Percentage decreases in elemental carbon were much larger in winter than in summer. These data suggest that emissions controls have been effective in reducing particulate concentrations not only in polluted areas but also across the United States. Despite the reduction in elemental carbon, the simultaneous decrease in non-absorbing particles implies that the overall radiative forcing from these changes was toward warming. The use of a 2005 instead of 1990 as a baseline for climate-relevant emissions from the United States would imply a significantly lower baseline for aerosol emissions. The use of older data will overestimate the possibility for future reductions in warming due to black carbon controls.

  15. Decreases in elemental carbon and fine particle mass in the United States

    Directory of Open Access Journals (Sweden)

    D. M. Murphy

    2011-05-01

    Full Text Available Observations at national parks and other remote sites show that average elemental carbon and fine particle mass concentrations in the United States both decreased by over 25 % between 1990 and 2004. Percentage decreases in elemental carbon were much larger in winter than in summer. These data suggest that emissions controls have been effective in reducing particulate concentrations not only in polluted areas but also across the United States. Despite the reduction in elemental carbon, the simultaneous decrease in non-absorbing particles implies that the overall radiative forcing from these changes was toward warming. The use of a 2005 instead of 1990 as a baseline for climate-relevant emissions from the United States would imply a significantly lower baseline for aerosol emissions. The use of older data will overestimate the possibility for future reductions in warming due to black carbon controls.

  16. Air Pressure-Assisted Centrifugal Dewatering of Concentrated Fine Sulfide Particles

    Directory of Open Access Journals (Sweden)

    R. Asmatulu

    2011-01-01

    Full Text Available An air pressure-assisted centrifugal dewatering method was developed and used for the dewatering of concentrated finesulfide particles, such as sphalerite, galena, and chalcopyrite. This filtration method was mainly designed to increase the filtration rate during the drainage cycle and, hence, produce drier filter cakes, which in turn could reduce the cost and emission problems/concerns of thermal dryers in the preparation plants. Several dewatering parameters, including applied pressure, centrifugal force (G-force, spin time, cake thickness, and surface hydrophobization, were tested to optimize the processing conditions. Test results showed that, at higher air pressure and centrifugal force, the cake moisture reduction was more than 70%, depending on the testing conditions. As a result, it can be-concluded that the novel filtration method effectively works on the dewatering of fine particles (–150 μm.

  17. The Influence of an Acoustic Field on the Bed Expansion of Fine Particles

    Institute of Scientific and Technical Information of China (English)

    Akash M. Langde; R.L.Sonolikar

    2011-01-01

    Fine particles are difficult to fluidize due to strong interparticle attraction.An attempt has been made to study the bed expansion of silica gel(dp=25μm) powder in presence of an acoustic field.A 135 mm diameter fluidized bed activated by an acoustic field with sound intensity up to 145 dB and frequency from 90 Hz to 170 Hz was studied.The effects of sound pressure level,sound frequency and particle loading on the bed expansion were investigated.Experimental results showed that,bed expansion was good in presence of acoustic field of particular frequency.In addition,it was observed that in presence of acoustic field the bed collapses slowly.

  18. Influence of milling time on fineness of Centella Asiatica particle size produced using planetary ball mill

    Science.gov (United States)

    Borhan, M. Z.; Ahmad, R.; Rusop, M.; Abdullah, S.

    2012-11-01

    Centella Asiatica (C. Asiatica)contains asiaticoside as bioactive constituent which can be potentially used in skin healing process. Unfortunately, the normal powders are difficult to be absorbed by the body effectively. In order to improve the value of use, nano C. Asiatica powder was prepared. The influence of milling time was carried out at 0.5, 2, 4, 6, 8 hours and 10 hours. The effect of ball milling at different times was characterized using particles size analysis and FTIR Spectroscopy. The fineness of ground product was evaluated by recording the z-Average (nm), undersize distribution and polydispersity index (PdI). The results show that the smallest size particles by mean is 233 nm while FTIR spectra shows that there is no changing in the major component in the C. Asiatica powders with milling time.

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

    Science.gov (United States)

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

    2009-08-15

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

  20. Characterization of Source Signatures of Fine Roadway Particles by Pyrolysis-GC-MS

    Science.gov (United States)

    van Bergen, S. K.; Holmén, B. A.

    2001-12-01

    Fine particulate matter, defined as particles with an aerodynamic diameter less than 2.5 μ m (PM2.5), is of growing concern due to its detrimental effects on human health and the environment. Roadway traffic generates a significant fraction of PM2.5 in urban areas. Since exposure to fine particles derived from mobile sources commonly occurs, understanding the physicochemical processes that contribute to the generation, transport and atmospheric reactivity of roadway PM is important. Factors that influence the properties of roadway PM include: the mass, number and size distribution of the particles as well as their chemical composition. These factors are partially determined by the sources of the roadway particles. The focus of this effort is to identify unique organic chemical profiles of known roadway sources of PM using a new rapid characterization technique. A pyrolysis GC-MS analytical method is being developed to uniquely characterize the sources of roadway PM2.5 such as brake dust, tire wear, and direct emissions from diesel and gasoline engines. The source profiles will be used in conjunction with measurements of the composition of ambient roadway PM to determine the importance of the various roadway sources. The advantages of this technique over conventional solvent extractions include: smaller (mg) sample mass requirements, short extraction times and minimal sample handing. Preliminary two-step pyrolysis results will be presented for PM samples from individual sources and an ambient roadway. Specific analytical issues that will be discussed include: modifications of commercial pyrolysis hardware to improve reproducibility; desorption versus pyrolysis; developing appropriate pyrolysis programs for heterogenous sample materials; and method detection limits.

  1. Extra-fine particle inhaled corticosteroids, pharma-cokinetics and systemic activity in children with asthma.

    Science.gov (United States)

    Wolthers, Ole D

    2016-02-01

    During recent years, extra-fine particle inhaled corticosteroids with a median aerodynamic diameter ≤2 μm have been introduced in the treatment of asthma. The aim of this paper was to review pharmacokinetics and systemic activity of extra-fine particle hydroalkane pressurized metered dose inhaled (pMDI) ciclesonide and beclomethasone dipropionate in children. A literature review was performed. Systemic bioavailability of oral and pulmonary deposition of extra-fine ciclesonide and beclomethasone dipropionate was 52% and 82%, the half-life in serum 3.2 and 1.5 h and first-pass hepatic metabolism >99% and 60%, respectively. Secondary analyses of urine cortisol/creatinine excretion found no effects of ciclesonide pMDI between 40 and 320 μg/day or of beclomethasone dipropionate pMDI between 80 and 400 μg/day. Ciclesonide pMDI 40, 80 and 160 μg/day caused no effects on short-term lower leg growth rate as assessed by knemometry. Ciclesonide 320 μg/day was associated with a numerically short-term growth suppression equivalent to 30% which was similar to 25% and 36% suppression caused by beclomethasone dipropionate HFA and CFC 200 μg/day, respectively. Consistent with the differences in key pharmacokinetic features, beclomethasone dipropionate is associated with a systemic activity detected by knemometry at a lower dose than ciclesonide. Whether that correlates with a clinically important difference remains to be explored. Assessments of systemic activity of beclomethasone dipropionate 180 μg/day as well as head-to-head comparisons are warranted. Preferably, such studies should apply the sensitive method of knemometry. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

    Institute of Scientific and Technical Information of China (English)

    Yumin Zhu; Hua Zhang; Liming Shao; Pinjing He

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW).In this study,we investigated fine particles of <2 mm,which are small fractions in MSW but constitute a significant component of the total heavy metal content,using bulk detection techniques.A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction.We also discussed the association,speciation and source apportionment of heavy metals.Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles.Zn-Cu,Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution.The overlapped enrichment,spatial association,and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles.The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.

  3. Study on fine particles influence on sodium sulfite and oxygen gas-liquid reaction

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Shuchang; Zhao, Bo; Wang, Shujuan; Zhuo, Yuqun; Chen, Changhe [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering

    2013-07-01

    Wet limestone scrubbing is the most common flue gas desulfurization process for control of sulfur dioxide emissions from the combustion of fossil fuels, and forced oxidation is a key part of the reaction. During the reaction which controlled by gas-liquid mass transfer, the fine particles' characteristic, size, solid loading and temperature has a great influence on gas-liquid mass transfer. In the present work is to explain how these factors influence the reaction between Na{sub 2}SO{sub 3} and O{sub 2} and find the best react conditions through experiment. The oxidation rate was experimentally studied by contacting pure oxygen with a sodium sulfite solution with active carbon particle in a stirred tank, and the system pressure drop was record by the pressure sensor. At the beginning the pressure is about 215 kPa and Na{sub 2}SO{sub 3} is about 0.5mol/L. The temperature is 40, 50, 60, 70, 80 C. Compare the results of no particles included, we can conclude that high temperature, proper loadings and smaller particles resulting in higher mass transfer coefficients k{sub L}.

  4. The PM2.5 Fine Particle Background Network of the German Meteorological Service-First Results

    OpenAIRE

    Uwe Kaminski; Mathieu Fricker; Volker Dietze

    2013-01-01

    Since 2009, the measurement of the background concentration of the fine particle fraction has been a part of the climate-monitoring program of the German Meteorological Service (DWD). These particles are of high health relevance as a critical air pollutant affecting processes like the scattering and absorption of solar radiation and influencing cloud formation and visibility. At 12 weather stations, the coarse (2.5 to 10 l m) and the fine particle fractions (PM2.5) are measured by means of pa...

  5. [Evaluation of Cellular Effects Caused by Lunar Regolith Simulant Including Fine Particles].

    Science.gov (United States)

    Horie, Masanori; Miki, Takeo; Honma, Yoshiyuki; Aoki, Shigeru; Morimoto, Yasuo

    2015-06-01

    The National Aeronautics and Space Administration has announced a plan to establish a manned colony on the surface of the moon, and our country, Japan, has declared its participation. The surface of the moon is covered with soil called lunar regolith, which includes fine particles. It is possible that humans will inhale lunar regolith if it is brought into the spaceship. Therefore, an evaluation of the pulmonary effects caused by lunar regolith is important for exploration of the moon. In the present study, we examine the cellular effects of lunar regolith simulant, whose components are similar to those of lunar regolith. We focused on the chemical component and particle size in particular. The regolith simulant was fractionated to effects of fine regolith simulant whose primary particle size is 5.10 μm. These regolith simulants were applied to human lung carcinoma A549 cells at concentrations of 0.1 and 1.0 mg/ml. Cytotoxicity, oxidative stress and immune response were examined after 24 h exposure. Cell membrane damage, mitochondrial dysfunction and induction of Interleukin-8 (IL-8) were observed at the concentration of 1.0 mg/ml. The cellular effects of the regolith simulant at the concentration of 0.1 mg/ml were small, as compared with crystalline silica as a positive control. Secretion of IL-1β and tumor necrosis factor-α (TNF-α) was observed at the concentration of 1.0 mg/ml, but induction of gene expression was not observed at 24 h after exposure. Induction of cellular oxidative stress was small. Although the cellular effects tended to be stronger in the effects of lunar regolith simulant such as cell membrane damage, induction of oxidative stress and proinflammatory effect.

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

    Science.gov (United States)

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

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

  7. Air pollution particles and iron homeostasis | Science ...

    Science.gov (United States)

    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, functional groups at the surface of retained particle complex iron available in the cell. In response to a reduction in concentrations of requisite iron, a functional deficiency can result intracellularly. Superoxide production by the cell exposed to a particle increases ferrireduction which facilitates import of iron with the objective being the reversal of the metal deficiency. Failure to resolve the functional iron deficiency following cell exposure to particles activates kinases and transcription factors resulting in a release of inflammatory mediators and inflammation. Tissue injury is the end product of this disruption in iron homeostasis initiated by the particle exposure. Elevation of available iron to the cell precludes deficiency of the metal and either diminishes or eliminates biological effects.General Significance: Recognition of the pathway for biological effects after particle exposure to involve a functional deficiency of iron suggests novel therapies such as metal supplementation (e.g. inhaled and oral). In addition, the demonstration of a shared mechanism of biological effects allows understanding the common clinical, physiological, and pathological presentation fol

  8. The chemical composition of fine ambient aerosol particles in the Beijing area

    Science.gov (United States)

    Nekat, Bettina; van Pinxteren, Dominik; Iinuma, Yoshiteru; Gnauk, Thomas; Müller, Konrad; Herrmann, Hartmut

    2010-05-01

    The strong economical growth in China during the last few decades led to heavy air pollution caused by significantly increased particle emissions. The aerosol particles affect not only the regional air quality and visibility, but can also influence cloud formation processes and the radiative balance of the atmosphere by their optical and microphysical properties. The ability to act as Cloud Condensation Nuclei (CCN) is related to microphysical properties like the hygroscopic growth or the cloud droplet activation. The chemical composition of CCN plays an important role on these properties and varies strongly with the particle size and the time of day. Hygroscopic or surface active substances can increase the hygroscopicity and lower the surface tension of the particle liquid phase, respectively. The presence of such compounds may result in faster cloud droplet activation by faster water uptake. The DFG project HaChi (Haze in China) aimed at studying physical and chemical parameters of urban aerosol particles in the Beijing area in order to associate the chemical composition of aerosol particles with their ability to act as CCN. To this end, two measurement campaigns were performed at the Wuqing National Ordinary Meteorological Observing Station, which is a background site near Beijing. The winter campaign was realized in March 2009 and the summer campaign took place from mid July 2009 to mid August 2009. Fine particles with an aerodynamic diameter smaller than or equal 1 μm were continuously sampled for 24h over the two campaigns using a DIGITEL high volume sampler (DHA-80). The present contribution presents and discusses the results of the chemical characterization of the DIGITEL filters samples. The filters were analyzed for the mass concentration, inorganic ions and carbon sum parameters like elemental (EC), organic (OC) and water soluble organic carbon (WSOC). The WSOC fraction was further characterized for hygroscopic substances like low molecular

  9. [Investigation on the characteristics and space-time distribution of fine particles in the atmosphere of residential area in Shanghai City].

    Science.gov (United States)

    Zhao, Jinzhuo; Li, Li; Qian, Chunyan; Jiang, Rongfang; Song, Weimin

    2012-01-01

    To observe the ambient fine particle pollution and the trend of its space-time distribution in residential areas in Shanghai, and to explore the effects of vehicle exhaust emission on the ambient fine particle pollution. Two residential areas A and B were selected for monitoring the pollution of fine particles. Area A is a normal residential area and area B is closed to a main road with heavy traffic. Four monitoring sites were set in the distance of 0 m, 50 m, 100 m and 200 m to the roadside and on a place 1.5 - 1.8 m above the ground. The concentration of fine particles in the air were measured in April, July, October 2010 and Jan 2011 for 1l0 days in each month in both areas using SIDEPAK AM510 (TSI, USA) fine particle monitors. The pollution of fine particle was varied in different seasons (spring > winter > autumn > summer) and at different time (with two peaks at 8:00 AM and 19:00 PM, corresponding to the rush hours). The pollution of fine particles is higher in residential area B than that in area A. The concentration of fine particles was reduced with the increase of the distance to the roadside. The level of fine particles in residential areas is comparatively high in Shanghai, and the vehicle exhaust emissions have significant effects on the concentration of fine particles in the atmosphere of residential area.

  10. Environmental and health impacts of fine and ultrafine metallic particles: Assessment of threat scores

    Energy Technology Data Exchange (ETDEWEB)

    Goix, Sylvaine [Université de Toulouse, INP-ENSAT, Av. Agrobiopôle, 31326 Castanet-Tolosan (France); UMR 5245 CNRS-INP-UPS, EcoLab (Laboratoire d' écologie fonctionnelle), Avenue de l' Agrobiopôle, BP 32607, 31326 Castanet-Tolosan (France); Lévêque, Thibaut [Université de Toulouse, INP-ENSAT, Av. Agrobiopôle, 31326 Castanet-Tolosan (France); UMR 5245 CNRS-INP-UPS, EcoLab (Laboratoire d' écologie fonctionnelle), Avenue de l' Agrobiopôle, BP 32607, 31326 Castanet-Tolosan (France); ADEME (French Agency for Environment and Energy Management), 20 Avenue du Grésillé, BP 90406, 49004 Angers Cedex 01 (France); Xiong, Tian-Tian [Université de Toulouse, INP-ENSAT, Av. Agrobiopôle, 31326 Castanet-Tolosan (France); UMR 5245 CNRS-INP-UPS, EcoLab (Laboratoire d' écologie fonctionnelle), Avenue de l' Agrobiopôle, BP 32607, 31326 Castanet-Tolosan (France); Schreck, Eva [Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse (France); and others

    2014-08-15

    This study proposes global threat scores to prioritize the harmfulness of anthropogenic fine and ultrafine metallic particles (FMP) emitted into the atmosphere at the global scale. (Eco)toxicity of physicochemically characterized FMP oxides for metals currently observed in the atmosphere (CdO, CuO, PbO, PbSO{sub 4}, Sb{sub 2}O{sub 3}, and ZnO) was assessed by performing complementary in vitro tests: ecotoxicity, human bioaccessibility, cytotoxicity, and oxidative potential. Using an innovative methodology based on the combination of (eco)toxicity and physicochemical results, the following hazard classification of the particles is proposed: CdCl{sub 2}∼CdO>CuO>PbO>ZnO>PbSO{sub 4}>Sb{sub 2}O{sub 3}. Both cadmium compounds exhibited the highest threat score due to their high cytotoxicity and bioaccessible dose, whatever their solubility and speciation, suggesting that cadmium toxicity is due to its chemical form rather than its physical form. In contrast, the Sb{sub 2}O{sub 3} threat score was the lowest due to particles with low specific area and solubility, with no effects except a slight oxidative stress. As FMP physicochemical properties reveal differences in specific area, crystallization systems, dissolution process, and speciation, various mechanisms may influence their biological impact. Finally, this newly developed and global approach could be widely used in various contexts of pollution by complex metal particles and may improve risk management. - Highlights: • Seven micro- and nano- monometallic characterized particles were studied as references. • Bioaccessibility, eco and cytotoxicity, and oxidative potential assays were performed. • According to calculated threat scores: CdCl{sub 2}∼CdO>CuO>PbO>ZnO>PbSO{sub 4}>Sb{sub 2}O{sub 3}.

  11. Generation of hydroxyl radicals from ambient fine particles in a surrogate lung fluid solution.

    Science.gov (United States)

    Vidrio, Edgar; Phuah, Chin H; Dillner, Ann M; Anastasio, Cort

    2009-02-01

    While it has been hypothesized that the adverse health effects associated with ambient particulate matter (PM) are due to production of hydroxyl radical (*OH), few studies have quantified *OH production from PM. Here we report the amounts of *OH produced from ambient fine particles (PM2.5) collected in northern California and extracted in a cell-free surrogate lung fluid (SLF). On average, the extracted particles produced 470 nmol *OH mg(-1)-PM2.5 during our 15-month collection period. There was a clear seasonal pattern in the efficiency with which particles generated *OH, with highest production during spring and summer and lowest during winter. In addition, nighttime PM was typically more efficient than daytime PM at generating *OH. Transition metals played the dominant role in *OH production: on average (+/-sigma), the addition of desferoxamine (a chelator that prevents metals from forming *OH) to the SLF removed (90 +/- 5) % of *OH generation. Furthermore, based on the concentrations of Fe in the PM2.5 SLF extracts, and the measured yield of *OH as a function of Fe concentration, dissolved iron can account for the majority of *OH produced in most of our PM2.5 extracts.

  12. The rural carbonaceous aerosols in coarse, fine, and ultrafine particles during haze pollution in northwestern China.

    Science.gov (United States)

    Zhu, Chong-Shu; Cao, Jun-Ji; Tsai, Chuen-Jinn; Shen, Zhen-Xing; Liu, Sui-Xin; Huang, Ru-Jin; Zhang, Ning-ning; Wang, Ping

    2016-03-01

    The carbonaceous aerosol concentrations in coarse particle (PM10: Dp ≤ 10 μm, particulate matter with an aerodynamic diameter less than 10 μm), fine particle (PM2.5: Dp ≤ 2.5 μm), and ultrafine particle (PM0.133: Dp ≤ 0.133 μm) carbon fractions in a rural area were investigated during haze events in northwestern China. The results indicated that PM2.5 contributed a large fraction in PM10. OC (organic carbon) accounted for 33, 41, and 62 % of PM10, PM2.5, and PM0.133, and those were 2, 2.4, and 0.4 % for EC (elemental carbon) in a rural area, respectively. OC3 was more abundant than other organic carbon fractions in three PMs, and char dominated EC in PM10 and PM2.5 while soot dominated EC in PM0.133. The present study inferred that K(+), OP, and OC3 are good biomass burning tracers for rural PM10 and PM2.5, but not for PM0.133 during haze pollution. Our results suggest that biomass burning is likely to be an important contributor to rural PMs in northwestern China. It is necessary to establish biomass burning control policies for the mitigation of severe haze pollution in a rural area.

  13. Reconciling satellite aerosol optical thickness and surface fine particle mass through aerosol liquid water

    Science.gov (United States)

    Nguyen, Thien Khoi V.; Ghate, Virendra P.; Carlton, Annmarie G.

    2016-11-01

    Summertime aerosol optical thickness (AOT) over the southeast U.S. is sharply enhanced over wintertime values. This seasonal pattern is unique and of particular interest because temperatures there have not warmed over the past 100 years. Patterns in surface fine particle mass are inconsistent with satellite reported AOT. In this work, we attempt to reconcile the spatial and temporal distribution of AOT over the U.S. with particle mass measurements at the surface by examining trends in aerosol liquid water (ALW), a particle constituent that scatters radiation and affects satellite AOT but is removed in mass measurements at routine surface monitoring sites. We employ the thermodynamic model ISORROPIAv2.1 to estimate ALW mass concentrations at Interagency Monitoring of PROtected Visual Environments sites using measured ion mass concentrations and North American Regional Reanalysis meteorological data. Excellent agreement between Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations AOT and estimated ALW provides a plausible explanation for the discrepancies in the geographical patterns of AOT and aerosol mass measurements.

  14. Production of De-asphalted Oil and Fine Asphalt Particles by Supercritical Extraction

    Institute of Scientific and Technical Information of China (English)

    赵锁奇; 许志明; 王仁安

    2003-01-01

    A continuous three-stage supercritical fluid extraction (SFE) process with a capacity of 1.0kg.h-1 was setup to extract petroleum residue by pentane to obtain more oil for further upgrading. A discharging system integrated to the bottom of the extractor was used to recover solvent as gas while asphalt was obtained as fine particles. The influence of operating conditions on the yield and quality of extracts, i.e., deasphalted oil (DAO) and resin, was studied in the range of temperature 150-220℃, pressure of 4.0-6.0 MPa and the mass ratio of solvent to oil feed (S/O) 2.5-5.0. The particle size distribution, apparent forms and the packing density, which vary with operating pressure, were measured. The particle structures were observed by SEM as well. With the modification to conventional processes, furnace can be eliminated for solvent recovery from asphalt phase, so as to reduce energy consumption.

  15. Preparation of fine silicon particles from amorphous silicon monoxide by the disproportionation reaction

    Science.gov (United States)

    Mamiya, Mikito; Takei, Humihiko; Kikuchi, Masae; Uyeda, Chiaki

    2001-07-01

    Fine Si particles have been prepared by the disproportionation reaction of silicon monoxide (SiO), that is: 2SiO→Si+SiO 2. Amorphous powders of SiO are heated between 900°C and 1400°C in a flow of Ar and the obtained specimens are analyzed by X-ray powder diffraction and high-resolution transmission electron microscopy. The treatments between 1000°C and 1300°C for more than 0.5 h result in origination of Si particles dispersed in amorphous oxide media. The particle size varies from 1-3 to 20-40 nm, depending on the heating temperature. Kinetic analyses of the reaction reveal that the activation energy is 1.1 eV (82.1 kJ mol -1). The specimens annealed above 1350°C changes into a mixture of Si and cristobalite, suggesting a solid state transformation in the surrounding oxides from the amorphous to crystalline states.

  16. X-ray diffraction and high-resolution TEM observations of biopolymer nanoskin-covered metallic copper fine particles: preparative conditions and surface oxidation states.

    Science.gov (United States)

    Yonezawa, Tetsu; Uchida, Yoshiki; Tsukamoto, Hiroki

    2015-12-28

    Metallic copper fine particles used for electro conductive pastes were prepared by the chemical reduction of cupric oxide microparticles in the presence of gelatin. After reduction, the fine particles were collected by decantation with pH control and washing, followed by drying at a moderate temperature. The surface oxidation state of the obtained copper fine particles could be considerably varied by altering the pH of the particle dispersion, as shown by X-ray diffraction and high-resolution transmission electron microscopy. Our results strongly indicate that decantation under a nitrogen atmosphere can prevent the oxidation of copper fine particles but a slight oxidation was found.

  17. Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m{sup 3} or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 {mu}g/cm{sup 2} of material which corresponds to about 10{mu}g/m{sup 3} of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5{mu}m. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs.

  18. Surface nanostructure formation mechanism of 45 steel induced by supersonic fine particles pombarding

    Institute of Scientific and Technical Information of China (English)

    Dema Ba; Shining Ma; Changqing Li; Fanjun Meng

    2008-01-01

    By means of supersonic fine particles bombarding (SFPB), a nanostruetured surface layer up to 15 μm was fabricated on a 45 steel plate with ferrite and pearlite phases. To reveal the grain refinement mechanism of SFPB-treated 45 steel, microstructure features of various sections in the treated surface were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Grain size increases with an increase of depth from the treated surface. Plastic deformation and grain refinement processes are accompanied by an increase in strain. Plastic deformation in the proeuteetoid ferrite phases has precedence over the pearlite phases. Grain refinement in the ferrite phases involves: the onset of dis-location lines (Dls), dislocation tangles (DTs) and dense dislocation walls (DDWs) in the original grains; the formation of fine la-mellar and roughly equiaxed cells separated by DDWs; by dislocation annihilation and rearrangement, the transformation of DDWS into subboundaries and boundaries and the formation of submicron grains or subgrains; the successive subdivision of grains to finer and finer scale, resulting in the formation of highly misoriented nano-grains. By contrast, eutectoid cementite phase accommodated swain in a sequence as follows: onset of elongated, bended and shear deformation under deformation stress of ferrites, short and thin cementites with a width of about 20-50 nm and discontinuous length were formed. Shorter and thinner cementites were developed into ultra-fine pieces under the action of high density dislocation and strains. At the top surface, some cementites were decomposed under severe plastic deformation. Experimental evidences and analysis indicate that surface nanocrystallization of 45 steel results from dislocation activities, high swains and high strain rate are necessary for the formation of nanocrystallites.

  19. Size distribution of chemical elements and their source apportionment in ambient coarse, fine, and ultrafine particles in Shanghai urban summer atmosphere.

    Science.gov (United States)

    Lü, Senlin; Zhang, Rui; Yao, Zhenkun; Yi, Fei; Ren, Jingjing; Wu, Minghong; Feng, Man; Wang, Qingyue

    2012-01-01

    Ambient coarse particles (diameter 1.8-10 microm), fine particles (diameter 0.1-1.8 microm), and ultrafine particles (diameter chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 +/- 2.18, 8.82 +/- 3.52, and 2.02 +/- 0.41 microg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

  20. Fine particle coal as a source of energy in small-user applications

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, S.

    1990-11-01

    The use of fine particle micronized coal as a source of energy for home heating applications has been explored in previous years under this program in a 150,000 Btu/hr pulse combustor. Experimental studies have been conducted on the combustion characteristics of micronized coal and combustion efficiencies have been measured. Emission levels of NO{sub x} and SO{sub 2} have been measured. In this final year of the program, the combustion and emissions characteristics of micronized coal were further explored in terms of the influence of stoichiometric ratio and frequency effects. Also, a model has been proposed which has potential for incorporating the unsteady mixing occurring in pulse combustors. 31 refs., 21 figs., 3 tabs.

  1. Trace element concentrations on fine particles in the Ohio River Valley

    Energy Technology Data Exchange (ETDEWEB)

    Tuncel, S.G.; Gordon, G.E.; Olmez, I.; Parrington, J.R.; Shaw, R.W. Jr.; Paur, R.J.

    1986-04-01

    Trace element compositions of airborne particles are important for determining sources and behavior of regional aerosol, as emissions from major sources are characterized by their elemental composition patterns. The authors investigated airborne trace elements in a complex regional environment through application of receptor models. A subset (200) of fine fraction samples in the Ohio River Valley (ORV) and analyzed by X-ray fluorescence (XRF) were reanalyzed by instrumental neutron activation analysis (INAA). The combined data set, XRF plus INAA, was subjected to receptor-model interpretations, including chemical mass balances (CMBs) and factor analysis (FA). Back trajectories of air masses were calculated for each sampling period and used with XRF data to select samples to be analyzed by INAA.

  2. A comparative study of the number and mass of fine particles emitted with diesel fuel and marine gas oil (MGO)

    Science.gov (United States)

    Nabi, Md. Nurun; Brown, Richard J.; Ristovski, Zoran; Hustad, Johan Einar

    2012-09-01

    The current investigation reports on diesel particulate matter emissions, with special interest in fine particles from the combustion of two base fuels. The base fuels selected were diesel fuel and marine gas oil (MGO). The experiments were conducted with a four-stroke, six-cylinder, direct injection diesel engine. The results showed that the fine particle number emissions measured by both SMPS and ELPI were higher with MGO compared to diesel fuel. It was observed that the fine particle number emissions with the two base fuels were quantitatively different but qualitatively similar. The gravimetric (mass basis) measurement also showed higher total particulate matter (TPM) emissions with the MGO. The smoke emissions, which were part of TPM, were also higher for the MGO. No significant changes in the mass flow rate of fuel and the brake-specific fuel consumption (BSFC) were observed between the two base fuels.

  3. Concentrations of fine, ultrafine, and black carbon particles in auto-rickshaws in New Delhi, India

    Science.gov (United States)

    Apte, Joshua, S.; Kirchstetter, Thomas W.; Reich, Alexander, H.; Deshpande, Shyam J.; Kaushik, Geetanjali; Chel, Arvind; Marshall, Julian D.; Nazaroff, William W.

    2011-08-01

    Concentrations of air pollutants from vehicles are elevated along roadways, indicating that human exposure in transportation microenvironments may not be adequately characterized by centrally located monitors. We report results from ˜180 h of real-time measurements of fine particle and black carbon mass concentration (PM 2.5, BC) and ultrafine particle number concentration (PN) inside a common vehicle, the auto-rickshaw, in New Delhi, India. Measured exposure concentrations are much higher in this study (geometric mean for ˜60 trip-averaged concentrations: 190 μg m -3 PM 2.5, 42 μg m -3 BC, 280 × 10 3 particles cm -3; GSD ˜1.3 for all three pollutants) than reported for transportation microenvironments in other megacities. In-vehicle concentrations exceeded simultaneously measured ambient levels by 1.5× for PM 2.5, 3.6× for BC, and 8.4× for PN. Short-duration peak concentrations (averaging time: 10 s), attributable to exhaust plumes of nearby vehicles, were greater than 300 μg m -3 for PM 2.5, 85 μg m -3 for BC, and 650 × 10 3 particles cm -3 for PN. The incremental increase of within-vehicle concentration above ambient levels—which we attribute to in- and near-roadway emission sources—accounted for 30%, 68% and 86% of time-averaged in-vehicle PM 2.5, BC and PN concentrations, respectively. Based on these results, we estimate that one's exposure during a daily commute by auto-rickshaw in Delhi is as least as large as full-day exposures experienced by urban residents of many high-income countries. This study illuminates an environmental health concern that may be common in many populous, low-income cities.

  4. The green synthesis of fine particles of gold using an aqueous extract of Monotheca buxifolia (Flac.)

    Science.gov (United States)

    Anwar, Natasha; Khan, Abbas; Shah, Mohib; Azam, Andaleeb; Zaman, Khair; Parven, Zahida

    2016-12-01

    This study deals with the synthesis and physicochemical investigation of gold nanoparticles using an aqueous extract of Monotheca buxifolia (Flac.). On the treatment of aqueous solution of tetrachloroauric acid with the plant extract, gold nanoparticles were rapidly fabricated. The synthesized particles were characterized by UV-Vis spectrophotometry (UV), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX) and Scanning electron microscopy (SEM). The formation of AuNPs was confirmed by noting the change in color through visual observations as well as via UV-Vis spectroscopy. UV‒Vis spectrum of the aqueous medium containing gold nanoparticles showed an absorption peak at around 540 nm. FTIR was used to identify the chemical composition of gold nanoparticles and Au-capped plant extract. The presence of elemental gold was also confirmed through EDX analysis. SEM analysis of the gold nanoparticles showed that they have a uniform spherical shape with an average size in the range of 70-78 nm. This green system showed to be better capping and stabilizing agent for the fine particles. Further, the antioxidant activity of Monotheca buxifolia (Flac.) extract and Au-capped with the plant extract was also evaluated using FeCl3/K3[Fe(CN)]6 in vitro assay.

  5. Multi-scale comparison of the fine particle removal capacity of urban forests and wetlands

    Science.gov (United States)

    Zhang, Zhenming; Liu, Jiakai; Wu, Yanan; Yan, Guoxin; Zhu, Lijuan; Yu, Xinxiao

    2017-04-01

    As fine particle (FP) pollution is harmful to humans, previous studies have focused on the mechanisms of FP removal by forests. The current study aims to compare the FP removal capacities of urban forests and wetlands on the leaf, canopy, and landscape scales. Water washing and scanning electron microscopy are used to calculate particle accumulation on leaves, and models are used to estimate vegetation collection, sedimentation, and dry deposition. Results showed that, on the leaf scale, forest species are able to accumulate more FP on their leaf surface than aquatic species in wetlands. On the canopy scale, horizontal vegetation collection is the major process involved in FP removal, and the contribution of vertical sedimentation/emission can be ignored. Coniferous tree species also showed stronger FP collection ability than broadleaf species. In the landscape scale, deposition on the forest occurs to a greater extent than that on wetlands, and dry deposition is the major process of FP removal on rain-free days. In conclusion, when planning an urban green system, planting an urban forest should be the first option for FP mitigation.

  6. Cooling of an internal-heated debris bed with fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z.L.; Sehgal, B.R. [Royal Institute of Technology, Div. of Nuclear Power Safety, Stockholm (Sweden)

    2001-07-01

    In this paper, an analytical model on dryout heat flux of ex-vessel debris beds with fines particles under top flooding conditions has been developed. The parametric study is performed on the effect of the stratification of the debris beds on the dryout heat flux. The calculated results show that the stratification configuration of the debris beds with smaller particles and lower porosity layer resting on the top of another layer of the beds has profound effect on the dryout heat flux for the debris beds both with and without a downcomer. The enhancement of the dryout heat flux by the downcomer is significant. The efficiency of the single downcomer on the enhancement of the dryout heat flux is also analyzed. This, in general, agrees well with experimental data. The model is also employed to perform the assessment on the coolability of the ex-vessel debris bed under representative accidental conditions. One conservative case is chosen, and it is found that the downcomer could be efficient measure to cool the debris bed and hence terminate the severe accident. (authors)

  7. Effects of oral administration of titanium dioxide fine-sized particles on plasma glucose in mice.

    Science.gov (United States)

    Gu, Ning; Hu, Hailong; Guo, Qian; Jin, Sanli; Wang, Changlin; Oh, Yuri; Feng, Yujie; Wu, Qiong

    2015-12-01

    Titanium dioxide (TiO2) is an authorized additive used as a food colorant, is composed of nano-sized particles (NP) and fine-sized particles (FP). Previous study reported that oral administration of TiO2 NPs triggers an increase in plasma glucose of mice. However, no previous studies have focused on toxic effects of TiO2 FPs on plasma glucose homeostasis following oral administration. In the current study, mice were orally administered TiO2 FPs greater than 100 nm in size (64 mg/kg body weight per day), and effects on plasma glucose levels examined. Our results showed that titanium levels was not changed in mouse blood, livers and pancreases after mice were orally administered TiO2 FPs. Biochemical analyzes showed that plasma glucose and ROS levels were not affected by TiO2 FPs. Histopathological results showed that TiO2 FPs did not induce pathology changes in organs, especially plasma glucose homeostasis regulation organs, such as pancreas and liver. Western blotting showed that oral administration of TiO2 FPs did not induce insulin resistance (IR) in mouse liver. These results showed that, TiO2 FPs cannot be absorbed via oral administration and affect plasma glucose levels in mice.

  8. Colloidal interactions between Langmuir-Blodgett bitumen films and fine solid particles.

    Science.gov (United States)

    Long, Jun; Zhang, Liyan; Xu, Zhenghe; Masliyah, Jacob H

    2006-10-10

    In oil sand processing, accumulation of surface-active compounds at various interfaces imposes a significant impact on bitumen recovery and bitumen froth cleaning (i.e., froth treatment) by altering the interfacial properties and colloidal interactions among various oil sand components. In the present study, bitumen films were prepared at toluene/water interfaces using a Langmuir-Blodgett (LB) upstroke deposition technique. The surface of the prepared LB bitumen films was found to be hydrophobic, comprised of wormlike aggregates containing a relatively high content of oxygen, sulfur, and nitrogen, indicating an accumulation of surface-active compounds in the films. Using an atomic force microscope, colloidal interactions between the LB bitumen films and fine solids (model silica particles and clay particles chosen directly from an oil sand tailing stream) were measured in industrial plant process water and compared with those measured in simple electrolyte solutions of controlled pH and divalent cation concentrations. The results show a stronger long-range repulsive force and weaker adhesion force in solutions of higher pH and lower divalent cation concentration. In plant process water, a moderate long-range repulsive force and weak adhesion were measured despite its high electrolyte content. These findings provide more insight into the mechanisms of bitumen extraction and froth treatment.

  9. Method for the removal of smut, fine dust and exhaust gas particles, particle catch arrangement for use in this method and use of the particle catch arrangement to generate a static electric field

    NARCIS (Netherlands)

    Ursem, W.N.J.; Marijnissen, J.C.; Roos, R.A.

    2007-01-01

    This inventions provides a method for the removal of smut, fine dust and exhaust gas particles from polluted air comprising providing a particle catch arrangement with a charged surface, the particle catch arrangement being arranged to generate a static electric field, wherein the electric field is

  10. God particle costs hit other science projects

    CERN Document Server

    Henderson, M

    2001-01-01

    The LHC is now running hugely over budget, jeapardising scores of other projects at CERN. The finanicial difficulties come as results from LEP have failed to convince many scientists that the Higgs boson, the particle the LHC is supposed to look for, exists at all. An official from PPARC has already stated that there is no question of additional funding coming from the UK to CERN to help resolve the problem (1 page).

  11. Differential effects of fine and coarse particles on daily emergency cardiovascular hospitalizations in Hong Kong

    Science.gov (United States)

    Qiu, Hong; Yu, Ignatius Tak-sun; Wang, Xiaorong; Tian, Linwei; Tse, Lap Ah; Wong, Tze Wai

    2013-01-01

    Few studies have investigated the relationship of hospital admissions for cardiovascular diseases with fine (PM2.5: particles with an aerodynamic diameter less than 2.5 μm) and coarse particles (PMc: particles with an aerodynamic diameter between 2.5 and 10 μm) simultaneously. We aimed to estimate the differential effects of PM2.5 and PMc on emergency hospital admissions for cardiovascular diseases, after controlling for the gaseous pollutants. We conducted a time series analysis in Hong Kong using daily emergency hospital admissions for cardiovascular diseases, PM2.5 and PMc concentrations from January 2000 to December 2005. PMc concentrations were estimated by subtracting PM2.5 from PM10 measurements. Generalized additive Poisson models allowing overdispersion and autocorrelation were used to examine the effects of PM2.5 and PMc simultaneously, adjusting for time trends, weather conditions, influenza outbreaks, and gaseous pollutants. In two-pollutant model, an interquartile range (IQR) increase in the 2-day moving average (lag01) concentration of PM2.5 and PMc corresponded to 1.86% (95% CI: 0.85%, 2.88%) and -0.16% (95% CI: -1.07%, 0.76%) change of emergency hospital admissions for total circulatory diseases respectively. Results were sensitive to further inclusion of nitrogen dioxide but not of ozone and sulfur dioxide. We did not find any effects of PMc on circulatory hospitalizations independent of PM2.5. In conclusion, we confirmed the stronger and significant adverse effects of PM2.5, but no independent effect of PMc on emergency cardiovascular hospitalizations. The biological mechanisms underlying the differential effects of PM2.5 and PMc on cardiovascular diseases were discussed.

  12. Thermal relaxation of interacting fine magnetic particles - field-cooled and zero-field-cooled magnetization variation

    Energy Technology Data Exchange (ETDEWEB)

    Jing Ju Lu; Hong Yuan Deng; Huei Li Huang E-mail: hlhuang@phys.ntu.edu.tw

    2000-02-01

    Dipole interaction makes average energy barrier of magnetic fine particles for thermal relaxation reduced while the corresponding blocking temperature distribution is a function of both dipolar interaction strength and particle size distribution of the system. Flatness and fast drop-off of the {lambda}-shape behavior of the field-cooled and zero-field-cooled magnetization varies with both dipolar intereaction strength and field level applied.

  13. Relationship between the composition of fine dust particles in the air and lung function in school children

    NARCIS (Netherlands)

    van Schayck, C.P.; Hogervorst, J.G.F.; de Kok, T.M.C.M.; Briede, J.J.; Wesseling, G.J.; Kleinjans, J.C.S.

    2006-01-01

    OBJECTIVE: To determine whether or not there is a relationship between the lung function of school children and the ability of fine dust particles in the air to generate radicals. DESIGN: Descriptive. METHOD: Six primary schools in locations with different traffic volumes were selected in

  14. Relationship between the composition of fine dust particles in the air and lung function in school children

    NARCIS (Netherlands)

    van Schayck, C.P.; Hogervorst, J.G.F.; de Kok, T.M.C.M.; Briede, J.J.; Wesseling, G.J.; Kleinjans, J.C.S.

    2006-01-01

    OBJECTIVE: To determine whether or not there is a relationship between the lung function of school children and the ability of fine dust particles in the air to generate radicals. DESIGN: Descriptive. METHOD: Six primary schools in locations with different traffic volumes were selected in Maastricht

  15. First phase monitoring studies of simulated benthic disturbance delineating movement of fine particles in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    . The travel effects of INDEX plume appears to be localized and confined within and around the disturbed zone (DZ) as resettlement of fine particles from the benthic plume was traced up to 2 km south and 12 to 18 km north of the DZ. The evidence does...

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

    Science.gov (United States)

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

  17. The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

    Energy Technology Data Exchange (ETDEWEB)

    Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

    2003-11-15

    The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

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

    Science.gov (United States)

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

    2011-08-01

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

  19. Science driving facilities for particle physics

    CERN Multimedia

    2011-01-01

    This week, CERN played host to the 10th ICFA (International Committee for Future Accelerators) seminar, which brought together some 200 scientists, government agency representatives and lab directors from around the world to take the pulse of our field. ICFA seminars take place every three years, and this time the emphasis was on science as the driving force for facilities.   The theme of this year’s seminar could not have been more timely. With austerity the global norm, it is more important than ever for science to point the way to the facilities we need, and for the global community to ensure that those facilities are planned at the global level. The LHC is already a machine for the world, and although CERN’s Member States have carried the bulk of the cost, it would not have been possible without contributions from around the globe. In the US, Fermilab’s focus has moved away from the high-energy frontier to the intensity frontier, which is every bit as impor...

  20. Predicting the Fine Particle Fraction of Dry Powder Inhalers Using Artificial Neural Networks.

    Science.gov (United States)

    Muddle, Joanna; Kirton, Stewart B; Parisini, Irene; Muddle, Andrew; Murnane, Darragh; Ali, Jogoth; Brown, Marc; Page, Clive; Forbes, Ben

    2017-01-01

    Dry powder inhalers are increasingly popular for delivering drugs to the lungs for the treatment of respiratory diseases, but are complex products with multivariate performance determinants. Heuristic product development guided by in vitro aerosol performance testing is a costly and time-consuming process. This study investigated the feasibility of using artificial neural networks (ANNs) to predict fine particle fraction (FPF) based on formulation device variables. Thirty-one ANN architectures were evaluated for their ability to predict experimentally determined FPF for a self-consistent dataset containing salmeterol xinafoate and salbutamol sulfate dry powder inhalers (237 experimental observations). Principal component analysis was used to identify inputs that significantly affected FPF. Orthogonal arrays (OAs) were used to design ANN architectures, optimized using the Taguchi method. The primary OA ANN r(2) values ranged between 0.46 and 0.90 and the secondary OA increased the r(2) values (0.53-0.93). The optimum ANN (9-4-1 architecture, average r(2) 0.92 ± 0.02) included active pharmaceutical ingredient, formulation, and device inputs identified by principal component analysis, which reflected the recognized importance and interdependency of these factors for orally inhaled product performance. The Taguchi method was effective at identifying successful architecture with the potential for development as a useful generic inhaler ANN model, although this would require much larger datasets and more variable inputs.

  1. Effects of supersonic fine particle bombarding on thermal cyclic failure lifetime of thermal barrier coating

    Institute of Scientific and Technical Information of China (English)

    CHEN Ya-jun; LIN Xiao-ping; WANG Zhi-ping; WANG Li-jun; JI Zhao-hui; DONG Yun

    2010-01-01

    Thermal barrier coating(TBC)consisting of a NiCoCrAlY bond coat(BC)and a ZrO2-8 wt.%Y2O3 topcoat(TC)was fabricated on the nickel-base supcralloy by air plasma spray(APS).The BC was trea-ted by supersonic fine particle bombarding(SFPB).Thermal cyclic failure and residual stress in thermally grown oxide(TGO)scale were studied by SEM with EDS and ruby fluorescence spectroscopy(RFS).As shown in the results,after treated by SFPB,thickening of TGO was relatively slow,which reduced the level of growth stress.The TBC with SFPB treatment was still remained well undergoing 350 times of thermal cycle.However,after thermal cycle with the same times,the separation of TC was observed in TBC without SFPB treatment.The residual stress analysis by RFS showed that the residual stress of SFPB-treated TBC increased with the increasing number of thermal cycle.The residual stress of conventional TBC reached a value of 650MPa at 350 times of cycle and that of SFPB-treated TBC only reached 532 MPa at 400 times of cycle.The BC with SFPB treatment after 400 times of cycle was analyzed by RFS,the high stress value was not observed in local thickened region of TGO.Thermal cycling resistance of TBC can be improved by the SFPB technology.

  2. Fine particles and oxidant pollution: developing an agenda for cooperative research.

    Science.gov (United States)

    Hidy, G M; Hales, J M; Roth, P M; Scheffe, R

    2000-04-01

    This paper describes a background for the North American Research Strategy for Tropospheric Ozone (NARSTO) cooperative program integrating studies of O3 and PM2.5. It discusses several important aspects for rationalizing NARSTO's trinational investigative approach, including (1) an outlook on the state of knowledge about fine particles in the troposphere and their origins in Canada, Mexico, and the United States; (2) the need for enhancement and strengthening of key field measurements in relation to tropospheric chemistry and a health effects component; and (3) the use of a central theme for advancing air quality modeling using evolving techniques to integrate and guide key process-oriented field campaigns. The importance of organizing a scientific program to acquire "policy-relevant" information is stressed, noting cooperative research directions that address combined PM2.5 and O3 issues, illustrated through exploration of hypothetical pathways of PM2.5 response to choices of O3 and PM precursor emission reductions. The information needed for PM2.5 research is noted to intersect in many cases with those of O3, but diverge in other cases. Accounting for these distinctions is important for developing NARSTO's strategy over the next decade.

  3. Probing the nature of the contact between fine particles by using ultrasound propagation

    Institute of Scientific and Technical Information of China (English)

    Antonio Castellanos; Xiaoping Jia; Carlos Soria-Hoyo; Jose Manuel Valverde

    2011-01-01

    The propagation velocity (vs) of an ultrasonic signal through a granular material depends on the type of interparticle contact.For noncohesive glass beads,a power law behavior vs ασc1/6 for consolidation stresses applied (ρc) above 1 MPa has been measured in previous work.This equation is compatible with Hertz's interaction law between elastic solids.In the present work,we have tested the propagation velocity of ultrasound signals through a sample of fine powder.The tensile strength and compactivity of the powder were previously measured by means of the Seville powder tester (SPT),indicating plastic deformation of the surface asperities in contact for small to moderate consolidation stresses.However,the measurements of ultrasound propagation at high consolidations presented here are compatible with Hertz's law.This finding suggests that for high consolidation stresses,surface asperities are flattened,and it is therefore the elastic deformation of the bulk of the particles that determines the transmission of ultrasonic pulses.

  4. Chemical composition and quantitative relationship between meteorological condition and fine particles in Beijing

    Institute of Scientific and Technical Information of China (English)

    WANG Jing-li; ZHANG Yuan-hang; SHAO Min; Liu Xu-lin; ZENG Li-min; CHENG Cong-lan; XU Xiao-feng

    2004-01-01

    The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM2.5 showed an increasing trend. To understand pollution characteristics of PM2.5 and its relationship with the meteorological conditions in Beijing, a one-year monitoring of PM2.5 mass concentration and correspondent meteorological parameters was performed in Beijing in 2001. The PM2.5 levels in Beijing were very high, the annual average PM2.5 concentration in 2001 was 7 times of the National Ambient Air Quality Standards proposed by US EPA. The major chemical compositions were organics, sulfate, crustals and nitrate. It was found that the mass concentrations of PM2.5 were influenced by meteorological conditions. The correlation between the mass concentrations of PM2.5 and the relative humidity was found. And the correlation became closer at higher relative humidity. And the mass concentrations of PM2.5 were negtive-correlated to wind speeds, but the correlation between the mass concentration of PM2.5 and wind speed was not good at stronger wind.

  5. Many-body dissipative particle dynamics modeling of fluid flow in fine-grained nanoporous shales

    Science.gov (United States)

    Xia, Yidong; Goral, Jan; Huang, Hai; Miskovic, Ilija; Meakin, Paul; Deo, Milind

    2017-05-01

    A many-body dissipative particle dynamics model, namely, MDPD, is applied for simulation of pore-scale, multi-component, multi-phase fluid flows in fine-grained, nanoporous shales. Since this model is able to simultaneously capture the discrete features of fluid molecules in nanometer size pores and continuum fluid dynamics in larger pores, and is relatively easy to parameterize, it has been recognized as being particularly suitable for simulating complex fluid flow in multi-length-scale nanopore networks of shales. A remarkable feature of this work is the integration of a high-resolution FIB-SEM (focused ion beam scanning electron microscopy) digital imaging technique to the MDPD model for providing 3D voxel data that contain the invaluable geometrical and compositional information of shale samples. This is the first time that FIB-SEM is seamlessly linked to a Lagrangian model like MDPD for fluid flow simulation, which offers a robust approach to bridging gaps between the molecular- and continuum-scales, since the relevant spatial and temporal scales are too big for molecular dynamics, and too small for computational fluid dynamics with known constitutive models. Simulations ranging from a number of benchmark problems to a forced two-fluid flow in a Woodford shale sample are presented. Results indicate that this model can be used to deliver reasonable simulations for multi-component, multi-phase fluid flows in arbitrarily complex pore networks in shales.

  6. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques.

    Science.gov (United States)

    Zhu, Yumin; Zhang, Hua; Shao, Liming; He, Pinjing

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.

  7. PREFACE: 8th International Conference on Fine Particle Magnetism (ICFPM2013)

    Science.gov (United States)

    2014-06-01

    The 8th International Conference on Fine Particle Magnetism (ICFPM) was held in Perpignan from 24 to 27 June 2013, and was the continuation of the previous meetings held in Bangor (1996), Rome (1991), Barcelona (1999), Pittsburg (2002), London (2004), Rome (2007) and Uppsala (2010). The next meeting will be organized by Profs. Robert D. Shull, George Hadjipanayis and Cindi Dennis, in 2016 at NIST, Gaithersburg (USA). ICFPM is a small-sized conference focused on the magnetism of nanoparticles. It provides an international forum for discussing the state-of-the-art understanding of physics of these systems, of their properties and the underlying phenomena, as approached from a variety of directions: theory and modelling, experiments on well characterized or model systems (both fabricated and synthetised), as well as experiments on technologically-relevant non-ideal systems. This meeting brought together about 120 participants working on experimental, theoretical and applied topics of the multidisciplinary research areas covered by magnetic nanoparticles, with focused interest on either single-particle or collective phenomena. The technical program of the conference was based on keynote conferences, invited talks, oral contributions and poster sessions, covering the following aspects: . Fabrication, synthesis, characterization . Single particle, surface and finite-size effects on magnetic properties . Magnetization dynamics, micro-wave assisted switching, dynamical coupling . Assemblies, collective effects, self-assembling and nanostructuring . Applications : hyperthermia, drug delivery, magneto-caloric, magneto-resistance, magneto-plasmonics, magnetic particle imaging This ICFPM edition was organized by the group Nanoscale Spin Systems of the laboratory PROMES of the CNRS (UPR8521), and Université de Perpignan Via Domitia. The meeting took place at the Congress Center of the city of Perpignan providing high-quality facilities for the technical program as well for the

  8. Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

    Directory of Open Access Journals (Sweden)

    Chenlong Duan

    2014-01-01

    Full Text Available Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed’s fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm, metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.

  9. Indoor and outdoor concentrations of fine particles, particle-bound PAHs and volatile organic compounds in Kaunas, Lithuania.

    Science.gov (United States)

    Kliucininkas, Linas; Martuzevicius, Dainius; Krugly, Edvinas; Prasauskas, Tadas; Kauneliene, Violeta; Molnar, Peter; Strandberg, Bo

    2011-01-01

    This complex study presents indoor and outdoor levels of air-borne fine particles, particle-bound PAHs and VOCs at two urban locations in the city of Kaunas, Lithuania, and considers possible sources of pollution. Two sampling campaigns were performed in January-February and March-April 2009. The mean outdoor PM(2.5) concentration at Location 1 in winter was 34.5 ± 15.2 µg m(-3) while in spring it was 24.7 ± 12.2 µg m(-3); at Location 2 the corresponding values were 36.7 ± 21.7 and 22.4 ± 19.4 µg m(-3), respectively. In general there was little difference between the PM concentrations at Locations 1 and 2. PM(2.5) concentrations were lower during the spring sampling campaign. These PM concentrations were similar to those in many other European cities; however, the levels of most PAHs analysed were notably higher. The mean sum PAH concentrations at Locations 1 and 2 in the winter campaign were 75.1 ± 32.7 and 32.7 ± 11.8 ng m(-3), respectively. These differences are greater than expected from the difference in traffic intensity at the two sites, suggesting that there is another significant source of PAH emissions at Location 1 in addition to the traffic. The low observed indoor/outdoor (I/O) ratios indicate that PAH emissions at the locations studied arise primarily from outdoor sources. The buildings at both locations have old windows with wooden frames that are fairly permissive in terms of air circulation. VOC concentrations were mostly low and comparable to those reported from Sweden. The mean outdoor concentrations of VOC's were: 0.7 ± 0.2, 3.0 ± 0.8, 0.5 ± 0.2, 3.5 ± 0.3, and 0.2 ± 0.1 µg m(-3), for benzene, toluene, ethylbenzene, sum of m-, p-, o-xylenes, and naphthalene, respectively. Higher concentrations of VOCs were observed during the winter campaign, possibly due to slower dispersion, slower chemical transformations and/or the lengthy "cold start" period required by vehicles in the wintertime. A trajectory analysis showed that air masses

  10. 利用胶质气体泡沫分离细微颗粒%Separation of Fine Particles by Using Colloidal Gas Aphrons

    Institute of Scientific and Technical Information of China (English)

    E.A.Mansur; 王运东; 戴猷元

    2004-01-01

    This paper presents a method of separation of fine particles, of the order of a few microns or less, from aqueous media by flotation using colloidal gas aphrons (CGAs) generated in aqueous solutions. More than 150experiments were conducted to study the effects of surfactant type, surfactant concentration, CGAs flow rate, and particle concentration on the removal efficiency (fine particles of polystyrene were used as a target compound). The results indicate that CGAs, generated from cationic surfactant of hexdecyltrimethyl ammonicum bromide (HTAB)and anionic surfactant of sodium dodecylbenzne sulfonate (SDBS), are an effective method for the separation of fine particles of polystyrene from wastewater. The flotation yields are higher than 97%.

  11. Exposure to fine particulate, black carbon, and particle number concentration in transportation microenvironments

    Science.gov (United States)

    Morales Betancourt, R.; Galvis, B.; Balachandran, S.; Ramos-Bonilla, J. P.; Sarmiento, O. L.; Gallo-Murcia, S. M.; Contreras, Y.

    2017-05-01

    This research determined intake dose of fine particulate matter (PM2.5), equivalent black carbon (eBC), and number of sub-micron particles (Np) for commuters in Bogotá, Colombia. Doses were estimated through measurements of exposure concentration, a surrogate of physical activity, as well as travel times and speeds. Impacts of travel mode, traffic load, and street configuration on dose and exposure were explored. Three road segments were selected because of their different traffic loads and composition, and dissimilar street configuration. The transport modes considered include active modes (walking and cycling) and motorized modes (bus, car, taxi, and motorcycle). Measurements were performed simultaneously in the available modes at each road segment. High average eBC concentrations were observed throughout the campaign, ranging from 20 to 120 μgm-3 . Commuters in motorized modes experienced significantly higher exposure concentrations than pedestrians and bicyclists. The highest average concentrations of PM2.5, eBC , and Np were measured inside the city's Bus Rapid Transit (BRT) system vehicles. Pedestrians and bicycle users in an open street configuration were exposed to the lowest average concentrations of PM2.5 and eBC , six times lower than those experienced by commuters using the BRT in the same street segment. Pedestrians experienced the highest particulate matter intake dose in the road segments studied, despite being exposed to lower concentrations than commuters in motorized modes. Average potential dose of PM2.5 and eBC per unit length traveled were nearly three times higher for pedestrians in a street canyon configuration compared to commuters in public transport. Slower travel speed and elevated inhalation rates dominate PM dose for pedestrians. The presence of dedicated bike lanes on sidewalks has a significant impact on reducing the exposure concentration for bicyclists compared to those riding in mixed traffic lanes. This study proposes a simple

  12. Isotopic composition for source identification of mercury in atmospheric fine particles

    Science.gov (United States)

    Huang, Qiang; Chen, Jiubin; Huang, Weilin; Fu, Pingqing; Guinot, Benjamin; Feng, Xinbin; Shang, Lihai; Wang, Zhuhong; Wang, Zhongwei; Yuan, Shengliu; Cai, Hongming; Wei, Lianfang; Yu, Ben

    2016-09-01

    The usefulness of mercury (Hg) isotopes for tracing the sources and pathways of Hg (and its vectors) in atmospheric fine particles (PM2.5) is uncertain. Here, we measured Hg isotopic compositions in 30 potential source materials and 23 PM2.5 samples collected in four seasons from the megacity Beijing (China) and combined the seasonal variation in both mass-dependent fractionation (represented by the ratio 202Hg / 198Hg, δ202Hg) and mass-independent fractionation of isotopes with odd and even mass numbers (represented by Δ199Hg and Δ200Hg, respectively) with geochemical parameters and meteorological data to identify the sources of PM2.5-Hg and possible atmospheric particulate Hg transformation. All PM2.5 samples were highly enriched in Hg and other heavy metals and displayed wide ranges of both δ202Hg (-2.18 to 0.51 ‰) and Δ199Hg (-0.53 to 0.57 ‰), as well as small positive Δ200Hg (0.02 to 0.17 ‰). The results indicated that the seasonal variation in Hg isotopic composition (and elemental concentrations) was likely derived from variable contributions from anthropogenic sources, with continuous input due to industrial activities (e.g., smelting, cement production and coal combustion) in all seasons, whereas coal combustion dominated in winter and biomass burning mainly found in autumn. The more positive Δ199Hg of PM2.5-Hg in spring and early summer was likely derived from long-range-transported Hg that had undergone extensive photochemical reduction. The study demonstrated that Hg isotopes may be potentially used for tracing the sources of particulate Hg and its vectors in the atmosphere.

  13. Application of mobile sampling to investigate spatial variation in fine particle composition

    Science.gov (United States)

    Li, Hugh Z.; Dallmann, Timothy R.; Gu, Peishi; Presto, Albert A.

    2016-10-01

    Long-term exposure to particulate matter (PM) is a major contributor to air pollution related deaths. Evidence indicates that metals play an important role in harming human health due to their redox potential. We conducted a mobile sampling campaign in 2013 summer and winter in Pittsburgh, PA to characterize spatial variation in PM2.5 mass and composition. Thirty-six sites were chosen based on three stratification variables: traffic density, proximity to point sources, and elevation. We collected filters in three time sessions (morning, afternoon, and overnight) in each season. X-ray fluorescence (XRF) was used to analyze concentrations of 26 elements: Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Cd, Sb, and Pb. Trace elements had a broad range of concentrations from 0 to 300 ng/m3. Comparison of data from mobile sampling filters with stationary monitors suggested that the mobile sampling strategy did not lead to a biased dataset. We developed Land Use Regression (LUR) models to describe spatial variation of PM2.5, Si, S, Cl, K, Ca, Ti, Cr, Fe, Cu, and Zn. Using ArcGIS-10.3 (ESRI, Redlands, CA), we extracted different independent variables related to traffic influence, land-use type, and facility emissions based on the National Emission Inventory (NEI). To validate LUR models, we used regression diagnostics such as leave-one-out cross validation (LOOCV), mean studentized prediction residual (MSPR), and root mean square of studentized residuals (RMS). The number of predictors in final LUR models ranged from 1 to 6. Models had an average R2 of 0.57 (SD = 0.16). Traffic related variables explained the most variability with an average R2 contribution of 0.20 (SD = 0.20). Overall, these results demonstrated significant intra-urban spatial variability of fine particle composition.

  14. Programming of mouse obesity by maternal exposure to concentrated ambient fine particles.

    Science.gov (United States)

    Chen, Minjie; Wang, Xiaoke; Hu, Ziying; Zhou, Huifen; Xu, Yanyi; Qiu, Lianglin; Qin, Xiaobo; Zhang, Yuhao; Ying, Zhekang

    2017-06-23

    Many diseases including obesity may originate through alterations in the early-life environment that interrupts fetal development. Increasing evidence has shown that exposure to ambient fine particles (PM2.5) is associated with abnormal fetal development. However, its long-term metabolic effects on offspring have not been systematically investigated. To determine if maternal exposure to PM2.5 programs offspring obesity, female C57Bl/6j mice were exposed to filtered air (FA) or concentrated ambient PM2.5 (CAP) during pre-conception, pregnancy, and lactation, and the developmental and metabolic responses of offspring were assessed. The growth trajectory of offspring revealed that maternal exposure to CAP significantly decreased offspring birth weight but increased body weight of adult male but not female offspring, and the latter was expressed as increased adiposity. These adult male offspring had increased food intake, but were sensitive to exogenous leptin. Their hypothalamic expression of Socs3 and Pomc, two target genes of leptin, was not changed, and the hypothalamic expression of NPY, an orexigenic peptide that is inhibited by leptin, was significantly increased. These decreases in central anorexigenic signaling were accompanied by reduced plasma leptin and its expression in adipose tissues, the primary source of circulating leptin. In contrast, maternal exposure did not significantly change any of these indexes in adult female offspring. Pyrosequencing demonstrated that the leptin promoter methylation of adipocytes was significantly increased in CAP-exposed male but not female offspring. Our data indicate that maternal exposure to ambient PM2.5 programs obesity in male offspring probably through alterations in the methylation of the promoter region of the leptin gene.

  15. Correlations between urban atmospheric light extinction coefficients and fine particle mass concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Trier, A.; Cabrini, N.; Ferrer, J. [Facultad de Ciencia, Universidad de Santiago de Chile, Santiago 2 (Chile); Olaeta, I. [SESMA, Santiago 1 (Chile)

    1997-07-01

    Total horizontal atmospheric light extinction coefficients as well as particle mass concentrations have been measured in downtown areas of Santiago de Chile, a heavily polluted city. Measurement campaigns were carried out in 1994 in 1995. Extinction measurements were made by a telephotometric technique in four wavelength bands; oscillating mass balance type instruments were used to measure PM2.5 and PM10 mass concentrations. The latter type instrument had not been available heretofore. The extensive continuous PM2.5 measurements are the first for this city. Strong and highly significant statistical correlations were found between extinction coefficients and mass concentrations, especially with the fine respirable or PM2.5 mass concentrations. Angstrom exponents and, in one case, mass extinction coefficients have been estimated. [Spanish] Se ha medido coeficientes atmosfericos totales horizontales de extincion de luz asi como concentraciones de masa de particulas atmosfericas en zonas centricas de Santiago de Chile, una ciudad altamente contaminada. Las campanas de medicion se han hecho en 1994 y en 1995. Las mediciones de extincion se han hecho por un metodo telefotometrico en cuatro bandas espectrales; las concentraciones de masa PM2.5 y PM10 se han medido con instrumentos del tipo de balanzas de masa oscilantes. Tales instrumentos no han estado disponibles durante trabajos anteriores. Las extensas mediciones continuas de concentraciones de masa PM2.5 son las primeras para Santiago de Chile. Se han encontrado fuertes correlaciones estadisticas, altamente significativas, entre coeficientes de extincion y concentraciones de masa, especialmente las concentraciones de particulas finas respirables PM2.5. Se han estimado tambien exponentes de Angstrom y, en un caso, coeficientes masicos de extincion.

  16. Beacons of discovery the worldwide science of particle physics

    CERN Document Server

    International Committee for Future Accelerators (ICFA)

    2011-01-01

    To discover what our world is made of and how it works at the most fundamental level is the challenge of particle physics. The tools of particle physics—experiments at particle accelerators and underground laboratories, together with observations of space—bring opportunities for discovery never before within reach. Thousands of scientists from universities and laboratories around the world collaborate to design, build and use unique detectors and accelerators to explore the fundamental physics of matter, energy, space and time. Together, in a common world-wide program of discovery, they provide a deep understanding of the world around us and countless benefits to society. Beacons of Discovery presents a vision of the global science of particle physics at the dawn of a new light on the mystery and beauty of the universe.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-15

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

  18. Levitation and collection of diamond fine particles in the rf plasma chamber equipped with a hot filament

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, S.; Shimizu, T.; Thomas, H. M.; Morfill, G. E. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Jacob, W. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2011-11-15

    We demonstrate the levitation of diamond fine particles in a H{sub 2} rf plasma chamber equipped with a hot filament and heated electrodes. The levitation conditions should be carefully chosen to compensate the strong thermophoretic forces caused by the filament and the electrodes. This levitation technique with the existence of a hot filament can be applied, e.g., for the efficient growth of diamond layers on seed particles injected and levitated in an rf plasma with reactive gases, e.g., CH{sub 4}/H{sub 2}. Additionally, the method for direct capture of levitated particles on a planar substrate was established, which is useful if it is necessary to analyze the particles after the levitation.

  19. Novel Wire-on-Plate Electrostatic Precipitator (WOP-EP) for Controlling Fine Particle and Nanoparticle Pollution.

    Science.gov (United States)

    Li, Ziyi; Liu, Yingshu; Xing, Yi; Tran, Thi-Minh-Phuong; Le, Thi-Cuc; Tsai, Chuen-Jinn

    2015-07-21

    A new wire-on-plate electrostatic precipitator (WOP-EP), where discharge wires are attached directly on the surface of a dielectric plate, was developed to ease the installation of the wires, minimize particle deposition on the wires, and lower ozone emission while maintaining a high particle collection efficiency. For a lab-scale WOP-EP (width, 50 mm; height, 20 mm; length, 180 mm) tested at the applied voltage of 18 kV, experimental total particle collection efficiencies were found as high as 90.9-99.7 and 98.8-99.9% in the particle size range of 30-1870 nm at the average air velocities of 0.50 m/s (flow rate, 30 L/min; residence time, 0.36 s) and 0.25 m/s (flow rate, 15 L/min; residence time, 0.72 s), respectively. Particle collection efficiencies calculated by numerical models agreed well with the experimental results. The comparison to the traditional wire-in-plate EP showed that, at the same applied voltage, the current WOP-EP emitted 1-2 orders of magnitude lower ozone concentration, had cleaner discharge wires after heavy particle loading in the EP, and recovered high particle collection efficiency after the grounded collection plate was cleaned. It is expected that the current WOP-EP can be scaled up as an efficient air-cleaning device to control fine particle and nanoparticle pollution.

  20. Health impacts due to personal exposure to fine particles caused by insulation of residential buildings in Europe

    Science.gov (United States)

    Gens, Alexandra; Hurley, J. Fintan; Tuomisto, Jouni T.; Friedrich, Rainer

    2014-02-01

    The insulation of residential buildings affects human exposure to fine particles. According to current EU guidelines, insulation is regulated for energy saving reasons. As buildings become tighter, the air exchange rate is reduced and, thus, the indoor concentration of pollutants is increased if there are significant indoor sources. While usually the effects of heat insulation and increase of the air-tightness of buildings on greenhouse gas emissions are highlighted, the negative impacts on human health due to higher indoor concentrations are not addressed. Thus, we investigated these impacts using scenarios in three European countries, i. e. Czech Republic, Switzerland and Greece. The assessment was based on modelling the human exposure to fine particles originating from sources of particles within outdoor and indoor air, including environmental tobacco smoke. Exposure response relationships were derived to link (adverse) health effects to the exposure. Furthermore, probable values for the parameters influencing the infiltration of fine particles into residential buildings were modelled. Results show that the insulation and increase of the air-tightness of residential buildings leads to an overall increase of the mean population exposure - and consequently adverse health effects - in all considered countries (ranging for health effects from 0.4% in Czech Republic to 11.8% in Greece for 100% insulated buildings) due to an accumulation of particles indoors, especially from environmental tobacco smoke. Considering only the emission reductions in outdoor air (omitting changes in infiltration parameters) leads to a decrease of adverse health effects. This study highlights the importance of ensuring a sufficient air exchange rate when insulating buildings, e. g. by prescribing heat ventilation and air conditioning systems in new buildings and information campaigns on good airing practice in renovated buildings. It also shows that assessing policy measures based on the

  1. The burden of lung cancer mortality attributable to fine particles in China.

    Science.gov (United States)

    Guo, Yuming; Zeng, Hongmei; Zheng, Rongshou; Li, Shanshan; Pereira, Gavin; Liu, Qiyong; Chen, Wanqing; Huxley, Rachel

    2017-02-01

    Although studies have examined the associations between fine particles (PM2.5) and lung cancer mortality in US and European countries, the evidence is still limited for China. In addition, no study has provided estimates of spatial variation in lung cancer mortality attributable to PM2.5 in China. In this study, we quantified the associations between lung cancer mortality and PM2.5, using a spatiotemporal model with observed data of lung cancer mortality from 75 communities from the National Cancer Registration of China from 1990 to 2009 and the annual concentrations of PM2.5 at 0.5°×0.5° spatial resolution. We also estimated lung cancer mortality burden attributable to PM2.5 in China, with predicted county level lung cancer deaths in 2005. We found that the PM2.5-lung cancer mortality associations were non-linear, with thresholds of 40μg/m(3) overall, 45μg/m(3) for male, 42μg/m(3) for female, 45μg/m(3) for those aged 30-64years, 48μg/m(3) for those aged 65-74years, and 40μg/m(3) for those aged 75years and more, above which the relative risks were 1.08 (95% CI: 1.07, 1.09), 1.07 (95% CI: 1.05, 1.08), 1.12 (95% CI: 1.1, 1.14), 1.05 (95% CI: 1.04, 1.07), 1.07 (95% CI: 1.06, 1.09), and 1.14 (95% CI: 1.12, 1.16) respectively. There were 51,219 (95% CI: 45,745-56,512) lung cancer deaths attributed to PM2.5 in 2005, with attributable fractions of 13.7% (95% CI: 12.23-15.11%) overall, 10.01% (95% CI: 8.37-11.58%) for men, 18.06% (95% CI: 15.81-20.18%) for women, 8.35% (95% CI: 6.07-10.51%) for those aged 65-74years, 9.73% (95% CI: 7.6-11.75%) for those aged 65-74years, 21.7% (95% CI: 19.27-23.99%) for those aged 75years or more. In conclusion, assuming a causal relation a reduction in exposure levels of PM2.5 below thresholds would avert a substantial number of deaths from lung cancer in China.

  2. Viscous properties of ferrofluids containing both micrometer-size magnetic particles and fine needle-like particles

    Science.gov (United States)

    Ido, Yasushi; Nishida, Hitoshi; Iwamoto, Yuhiro; Yokoyama, Hiroki

    2017-06-01

    Ferrofluids containing both micrometer-size spherical magnetic particles and nanometer-size needle-like nonmagnetic hematite particles were newly produced. Average length of long axis of the needle-like nonmagnetic particles was 194 nm and the aspect ratio was 8.3. Shear stress and viscosity were measured using the rheometer with the additional equipment for viscosity measurements in the presence of magnetic field. When the total volume fraction of particles in the fluid is constant (0.30), there is the specific mixing ratio of the particles to increase viscosity of the fluid drastically in the absence of magnetic field due to the percolation phenomenon. The fluid of the specific mixing ratio shows solid-like behavior even in the absence of magnetic field. Mixing the needle-like nonmagnetic particles causes strong yield stress and strong viscous force in the presence of magnetic field.

  3. Contribution of image analysis to the definition of explosibility of fine particles resulting from waste recycling process

    Science.gov (United States)

    Gente, V.; La Marca, F.

    2007-09-01

    In waste recycling processes, the development of comminution technologies is one of the main actions to improve the quality of recycled products. This involves a rise in fine particles production, which could have some effects on explosibility properties of materials. This paper reports the results of experiments done to examine the explosibility of the fine particles resulting from waste recycling process. Tests have been conducted for the products derived from milling processes operated in different operative conditions. In particular, the comminution tests have been executed varying the milling temperature by refrigerant agents. The materials utilized in explosibility tests were different typologies of plastics coming from waste products (PET, ABS and PP), characterized by size lower than 1 mm. The results of explosibility tests, carried out by mean of a Hartmann Apparatus, have been compared with the data derived from image analysis procedure aimed to measure the morphological characteristics of particles. For each typology of material, the propensity to explode appears to be correlated not only to particle size, but also to morphological properties, linked to the operative condition of the milling process.

  4. Filtration efficiency validation of glass wool during thermal desorption-gas chromatography-mass spectrometer analysis of fine atmospheric particles.

    Science.gov (United States)

    Hao, Liang; Wu, Dapeng; Ding, Kun; Meng, Hu; Yan, Xiaohui; Guan, Yafeng

    2015-02-06

    Thermal desorption-gas chromatography-mass spectrometer (TD-GC-MS) technique has been widely used for analysis of semi-violate organic compounds on atmospheric aerosol. To prevent GC column from being damaged by fine solid particles during thermal desorption process, glass wool as filter mat is indispensible. However, the filtration efficiency has never been validated. In this paper, the most penetrating particle size and the minimum packing thickness of glass wool were calculated based on classical filtration theory. According to the calculation results, packing parameters of glass wool were optimized experimentally using silica particles. It is demonstrated that glass wool with a packing thickness of 30 mm, solidity of 0.039 can effectively block these fine solid particles from penetrating at normal thermal desorption conditions (T=300°C, u=0.4-4 cm/s). Finally, the filtration efficiency of glass wool was further confirmed with real PM2.5 samples. Under the validated filtration condition, TD-GC-MS was applied for the analysis of non-polar organic compounds on real PM2.5 samples, and very good results were obtained.

  5. Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

    Institute of Scientific and Technical Information of China (English)

    NIU; Yuwen; HE; Lingyan; HU; Min; ZHANG; Jing; ZHAO; Yunliang

    2006-01-01

    Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2004. Totally 30 sets of 24 h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal variations and secondary pollution characteristics of fine particles during the sampling periods were discussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respectively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol components in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South China Sea in summer, and the air quality was good. The prevailing wind in winter was from Mainland China to the north, and the polluted air mass led to poor air quality.

  6. Particle Formation from Pulsed Laser Irradiation of SootAggregates studied with scanning mobility particle sizer, transmissionelectron microscope and near-edge x-ray absorption fine structure.

    Energy Technology Data Exchange (ETDEWEB)

    Michelsen, Hope A.; Tivanski, Alexei V.; Gilles, Mary K.; vanPoppel, Laura H.; Dansson, Mark A.; Buseck, Peter R.; Buseck, Peter R.

    2007-02-20

    We investigated the physical and chemical changes induced in soot aggregates exposed to laser radiation using a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope to perform near-edge x-ray absorption fine structure spectroscopy. Laser-induced nanoparticle production was observed at fluences above 0.12 J/cm(2) at 532 nm and 0.22 J/cm(2) at 1064 nm. Our results indicate that new particle formation proceeds via (1) vaporization of small carbon clusters by thermal or photolytic mechanisms, followed by homogeneous nucleation, (2) heterogeneous nucleation of vaporized carbon clusters onto material ablated from primary particles, or (3) both processes.

  7. Particle morphologies and formation mechanisms of fine volcanic ash aerosol collected from the 2006 eruption of Augustine Volcano, Alaska

    Science.gov (United States)

    Rinkleff, P. G.; Cahill, C. F.

    2010-12-01

    Fine volcanic ash aerosol (35-0.09um) erupted in 2006 by Augustine Volcano, southwest of Anchorage, Alaska was collected by a DRUM cascade impactor and analyzed by scanning electron microscopy for individual particle chemistry and morphology. Results of these analyses show ash particles occur as either individual glass shard and mineral phase (plagioclase, magnetite, ilmenite, hornblende, etc.) particles or aggregates thereof. Individual glass shard ash particles are angular, uniformly-sized, consist of calc-alkaline whole-rock elements (Si, Al, Fe, Na, and Ca) and are not collocated on the sample media with non-silicate, Cl and S bearing sea salt particles. Aggregate particles occur as two types: pure ash aggregates and sea salt-cored aggregates. Pure ash aggregates are made up of only ash particles and contain no other constituents. Sea salt-cored aggregates are ash particles commingled with sea salts. Determining the formation processes of the different ash particle types need further investigation but some possibilities are proposed here. Individual ash particles may exist when the ambient air is generally dry, little electrical charge exists on ash particles, the eruptive cloud is generally dry, or the number of individual particles exceeds the scavenging capacity of the water droplets present. Another possibility is that ash aggregates may break apart as relative humidity drops over time and causes ash-laden water droplets to evaporate and subsequently break apart. Pure ash aggregates may form when the ambient air and plume is relatively dry but the ash has a significant charge to cause ash to aggregate. Or they could form during long-range transport when turbulent or Brownian motion can cause ash particles to collide and coagulate. Pure ash aggregates could also form as a result of water droplet scavenging and subsequent evaporation of water droplets, leaving behind only ash. In this case, droplets would not have interacted with a sea salt

  8. Using monosaccharide anhydrides to estimate the impact of wood combustion on fine particles in the Helsinki Metropolitan Area

    Energy Technology Data Exchange (ETDEWEB)

    Saarnio, K.; Saarikoski, S. [Finnish Meteorological Institute, Helsinki (Finland); Niemi, J.V. [HSY Helsinki Region Environmental Services Authority, Helsinki (Finland)

    2012-11-01

    The spatiotemporal variation of ambient particles under the influence of biomass burning emissions was studied in the Helsinki Metropolitan Area (HMA) in selected periods during 2005-2009. Monosaccharide anhydrides (MAs; levoglucosan, mannosan and galactosan), commonly known biomass burning tracers, were used to estimate the wood combustion contribution to local particulate matter (PM) concentration levels at three urban background sites close to the city centre, and at three suburban sites influenced by local small-scale wood combustion. In the cold season (October-March), the mean MAs concentrations were 115-225 ng m{sup -3} and 83-98 ng m{sup -} {sup 3}at the suburban and urban sites, respectively. In the warm season, the mean MAs concentrations were low (19-78 ng m{sup -3}), excluding open land fire smoke episodes (222-378 ng m{sup -}3{sup )}. Regionally distributed wood combustion particles raised the levels over the whole HMA while particles from local wood combustion sources raised the level at suburban sites only. The estimated average contribution of wood combustion to fine particles (PM{sub 2.5}) ranged from 18% to 29% at the urban sites and from 31% to 66% at the suburban sites in the cold season. The PM measurements from ambient air and combustion experiments showed that the proportions of the three MAs can be utilised to separate the wildfire particles from residential wood combustion particles. (orig.)

  9. A study of ambient fine particles at Tianjin International Airport, China.

    Science.gov (United States)

    Ren, Jianlin; Liu, Junjie; Li, Fei; Cao, Xiaodong; Ren, Shengxiong; Xu, Bin; Zhu, Yifang

    2016-06-15

    The total count number concentration of particles from 10 to 1000nm, particle size distribution, and PM2.5 (aerodynamic diameter≤2.5μm) mass concentration were measured on a parking apron next to the runway at Tianjin International Airport in China. The data were collected 250, 270, 300, 350, and 400m from the runway. Wind direction and wind speed played important roles in determining the characteristics of the atmospheric particles. An inverted U-shaped relationship was observed between the measured particle number concentration and wind speed, with an average peak concentration of 2.2×10(5)particles/cm(3) at wind speeds of approximately 4-5m/s. The atmospheric particle number concentration was affected mainly by aircraft takeoffs and landings, and the PM2.5 mass concentration was affected mainly by the relative humidity (RH) of the atmosphere. Ultrafine particles (UFPs, diameter<100nm), with the highest number concentration at a particle size of approximately 16nm, dominated the measured particle size distributions. The calculated particle emission index values for aircraft takeoff and landing were nearly the same, with mean values of 7.5×10(15)particles/(kg fuel) and 7.6×10(15)particles/(kg fuel), respectively. The particle emission rate for one aircraft during takeoff is two orders of magnitude higher than for all gasoline-powered passenger vehicles in Tianjin combined. The particle number concentrations remained much higher than the background concentrations even beyond 400m from the runway.

  10. The 2005 Study of Organic Aerosols at Riverside (SOAR-1: instrumental intercomparisons and fine particle composition

    Directory of Open Access Journals (Sweden)

    K. S. Docherty

    2011-12-01

    Full Text Available Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR to investigate the chemical composition and potential sources of fine particles (PMf in the inland region of Southern California. In this paper, we briefly summarize the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July–15 August, provide detailed intercomparisons of high-resolution aerosol mass spectrometer (HR-AMS measurements against complementary measurements, and report the average composition of PMf including the composition of the organic fraction measured by the HR-AMS. Daily meteorology and gas-phase species concentrations were highly consistent, displaying clear diurnal cycles and weekday/weekend contrast. HR-AMS measurements of non-refractory submicron (NR-PM1 mass are consistent and highly correlated with those from a filter dynamics measurement system tapered-element oscillating microbalance (TEOM, while the correlation between HR-AMS and heated TEOM measurements is lower due to loss of high volatility species including ammonium nitrate from the heated TEOM. Speciated HR-AMS measurements are also consistent with complementary measurements as well as with measurements from a collocated compact AMS while HR-AMS OC is similar to standard semi-continuous Sunset measurements within the combined uncertainties of both instruments. A correction intended to account for the loss of semi-volatile OC from the Sunset, however, yields measurements ~30% higher than either HR-AMS or standard Sunset measurements. On average, organic aerosol (OA was the single largest component of PMf. OA composition was investigated using both elemental analysis and positive matrix factorization (PMF of HR-AMS OA spectra. Oxygen is the main heteroatom during SOAR-1, with O/C exhibiting a diurnal minimum of 0.28 during the morning

  11. The 2005 Study of Organic Aerosols at Riverside (SOAR-1: instrumental intercomparisons and fine particle composition

    Directory of Open Access Journals (Sweden)

    K. S. Docherty

    2011-02-01

    Full Text Available Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR to investigate sources and chemical composition of fine particles (PMf in the inland region of Southern California. This paper briefly summarizes the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July–15 August and provides detailed intercomparisons of complementary measurements and average PMf composition during this period. Daily meteorology and gas-phase species concentrations were highly repetitive with meteorological and gas-phase species concentrations displaying clear diurnal cycles and weekday/weekend contrast, with organic aerosol (OA being the single largest component contributing approximately one-third of PMf mass. In contrast with historical characterizations of OA in the region, several independent source apportionment efforts attributed the vast majority (~80% of OA mass during SOAR-1 to secondary organic aerosol (SOA. Given the collocation of complementary aerosol measurements combined with a dominance of SOA during SOAR-1, this paper presents new results on intercomparisons among several complementary measurements and on PMf composition during this period. Total non-refractory submicron (NR-PM1 measurements from a high-resolution aerosol mass spectrometer (HR-AMS are compared with measurements by tapered element oscillating microbalances (TEOM including a filter dynamics measurement system (TEOMFDMS. NR-PM1 is highly correlated with PM2.5 TEOMFDMS measurements and accounts for the bulk of PM2.5 mass with the remainder contributed primarily by refractory material. In contrast, measurements from a heated TEOM show substantial losses of semi-volatile material, including ammonium nitrate and semi-volatile organic material. Speciated HR-AMS measurements are

  12. Effect of shot peening using ultra-fine particles on fatigue properties of 5056 aluminum alloy under rotating bending

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Shoichi, E-mail: kikuchi@mech.kobe-u.ac.jp [Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe-shi, Hyogo 657-8501 (Japan); Nakamura, Yuki [Department of Mechanical Engineering, National Institute of Technology, Toyota College, 2-1 Eisei-cho, Toyota-shi, Aichi 471-8525 (Japan); Nambu, Koichiro [Department of Mechanical Engineering, National Institute of Technology, Suzuka College, Shiroko-cho, Suzuka-shi, Mie 510-0294 (Japan); Ando, Masafumi [Innovation Team, IKK SHOT Co. Ltd., 412-4, Nunowari, Minami-Shibata-machi, Tokai-shi, Aichi 476-0001 (Japan)

    2016-01-15

    Shot peening using particles 10 μm in diameter (ultra-fine particle peening: Ultra-FPP) was introduced to improve the fatigue properties of 5056 aluminum alloy. The surface microstructures of the Ultra-FPP treated specimens were characterized using a micro-Vickers hardness tester, scanning electron microscopy (SEM), X-ray diffraction (XRD), non-contact scanning white light interferometry, and electron backscatter diffraction (EBSD). The Ultra-FPP treated specimen had higher hardness than the conventional FPP treated specimen with a short nozzle distance due to the high velocity of the ultra-fine particles. Furthermore, the surface hardness of the Ultra-FPP treated specimen tended to increase as the peening time decreased. Fatigue tests were performed in air at room temperature using a cantilever-type rotating bending fatigue testing machine. It was found that the fatigue life of the Ultra-FPP treated specimen tended to increase with decreasing peening time. Mainly, the Ultra-FPP improved the fatigue properties of 5056 aluminum alloy in the very high cycle regime of more than 10{sup 7} cycles compared with the un-peened specimens. This is because the release of the compressive residual stress is small during fatigue tests at low stress amplitudes.

  13. Heavy metal pollution in sediment from Sisimiut, Greenland. Adsorption to organic matter and fine particles

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Villumsen, Arne

    2006-01-01

    . The pollution could be linked to human activities in Sisimiut, a link that have not been investigated previously in Greenland. Except from the most polluted samples there was good correlation between heavy metal concentration and organic matter. Also some relation between fine fraction and heavy metal...

  14. The effect of the presence of fine YSZ particles on the performance of porous nickel electrodes

    NARCIS (Netherlands)

    Boer, de B.; Gonzalez, M.; Bouwmeester, H.J.M.; Verweij, H.

    2000-01-01

    The electrochemical performance of a porous nickel electrode with its surface modified by deposition with fine yttria-stabilised zirconia (YSZ) powder is compared with that of the ‘bare’ electrode. Image analysis of the electrode microstructure yields values for the triple phase boundary (TPB) lengt

  15. Enhancement of CO2 Absorption under Taylor Flow in the Presence of Fine Particles

    Institute of Scientific and Technical Information of China (English)

    CAI Wangfeng; ZHANG Jiao; ZHANG Xubin; WANG Yan; QI Xiangjuan

    2013-01-01

    The physical absorption of CO2 in water containing different types of particles was studied in a microchannel operated under Taylor flow.The maximum enhancement factors of 1.43-2.15 were measured for activated carbon(AcC)particles.The analysis shows that the enhancement effect can be attributed to the shuttle mechanism.Considering the separate contributions of mass transfer from bubble cap and liquid film,a heterogeneous enhancement model is developed.According to this model,the enhancement factors ECap,EFilm and Eov are mainly determined by mass transfer coefficient KL(KLCap and KL Film),adsorptive capacity of particles m,and coverage fraction of particles at gas-liquid interface ζ.With,both effects of particle-to-interface adhesion and apparent viscosity included,the model predicts the enhancement effect of AcC particles reasonably well.

  16. Study on the daytime OH radical and implication for its relationship with fine particles over megacity of Shanghai, China

    Science.gov (United States)

    Nan, Jialiang; Wang, Shanshan; Guo, Yanlin; Xiang, Yajing; Zhou, Bin

    2017-04-01

    To investigate on the daytime OH and its implication to fine particle, the long-path differential optical absorption spectroscopy (LP-DOAS) system was employed to observe the main OH precursors of O3, HCHO and HONO, as well as NO2 and NO3 radical from April to August 2013 over Shanghai, China. The main OH production paths from HONO, HCHO and O3 were estimated to be occupied around 57.6%, 30.5% and 11.9% during daytime. The daytime OH radical concentration under steady-state was averaged at 1.02 × 107 molec cm-3, which was significantly impacted by the photolytic processes. The relationship between photolysis frequency j(O1D) and OH radical suggests that heavy fine particle loads can make the photolytic reactions less efficiently and decrease the OH production and concentration. Utilizing CO as the indicator, the part of PM2.5 mass related to primary emitted sources was found less impacted by the OH levels. The contribution of secondary organic aerosol with metrics of O3 was enhanced with the increases of the OH levels, while secondary inorganic part of PM2.5 was favor of the condition that smaller OH concentrations that 5 × 105-5 × 106 molec cm-3. Meantime, a simplified multivariate model was employed to evaluate the influences of OH levels on different parts of fine particles related to different emission and sources. Normalized by solar radiation, this part of OH unrelated to radiation was found to be inversely related to the PM2.5, which indicates the self-cleansing capability of the atmosphere.

  17. Effect of fine solid particles on absorption rate of gaseous CO2

    Institute of Scientific and Technical Information of China (English)

    Sumin LU; Youguang MA; Shuhua SHEN; Chunying ZHU

    2008-01-01

    The influence of the properties of solid particles in slurry on the absorption of CO2 in the slurry was inves-tigated in a stirred thermostatic reactor. The absorption experiments were carried out in three different slurries con-sisting of water, cyclohexane and soybean oil, respectively, and three kinds of solid particles (active carbon, active alu-mina and silica gel) were incorporated into each of the above mentioned slurries separately. The experimental results show that the active carbon particles could enhance the absorption rate of gaseous CO2 in the aqueous slurry, while in the cyclohexane slurry, active carbon particles indi-cated no the absorption enhancement effect. However, it was observed that the active alumina and silica gel particles could enhance the absorption rate of CO2 in the cyclohex-ane slurry. These phenomena indicate that the solid part-icles, which could enhance the gaseous CO2 absorption rate, should possess two properties simultaneously, i.e. they rejected the solvent and had higher adsorption capacity for the solute. The experimental results also show that, as for those solid particles which could enhance the gas absorption rate, the enhancement increased quickly with the increase of solid concentration in slurry at first, and then reached a constant value gradually. It was also found that the enhancement factor was related to the coverage fraction of solid particles on the gas-liquid interface, and due to the reduction of surface fraction with increasing stirred speed, the enhancement factor decreased.

  18. Formation and emission of fine particles from two coal-fired power plants

    DEFF Research Database (Denmark)

    Nielsen, M.T.; Livbjerg, H.; Fogh, C.L.

    2002-01-01

    , and Fe under reducing conditions. Several other ash-contained elements, e.g., P, Ba, Co, Cu, Mn, Ni, Ph, V, and Zn, are partly vaporized in the boiler and enrich the small particles when they condense during cooling of the flue gas. Due to the higher penetration of the small particles through the filter...

  19. High viscosity gas fluidization of fine particles: An extended window of quasihomogeneous flow.

    Science.gov (United States)

    Valverde, Jose Manuel; Castellanos, Antonio

    2006-08-01

    We explore the role of gas viscosity in the behavior of gas-fluidized beds of fine powders by means of experimental measurements using nitrogen and neon as fluidizing gases, and theoretical considerations. The existence of a nonbubbling fluidlike regime has been recently observed in beds of fine powders fluidized with nitrogen. Our experiments with neon reveal a discontinuous transition from heterogeneous fluidization to a highly expanded homogeneous fluidization state. We point out that increasing gas viscosity enhances the coherence of agglomerate swarms, which promotes a local void-splitting mechanism, thus improving the uniformity of fluidization. Our theoretical analysis predicts that further increase of gas viscosity would produce a full suppression of the bubbling regime, i.e., the uniformly fluidized bed would undergo a direct transition to a turbulent regime as seen in beds of nanoparticles fluidized by nitrogen and in liquid-fluidized beds of moderate-density beads.

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

    OpenAIRE

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

    2006-01-01

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

  1. Formation of Cube Texture in Nominally Pure Aluminum With Fine Particle Dispersion

    OpenAIRE

    Saimoto, S.; Li, Jian; Langelaan, G.; Diak, B. J.; Shimizu, J

    1996-01-01

    An X-ray method to observe in-situ cube grain growth during recrystallization has been devised using a hot stage to measure the growth kinetics. Complementary studies, using electron channelling contrast, electron backscattered pattern and X-ray textural analysis, revealed that specific thermal-mechanical history can precipitate out Fe solutes such that the matrix is sufficiently pure to undergo continuous recrystallization even though a fine distribution of precipitate are initially formed. ...

  2. Impacts of Roadway Emissions on Urban Fine Particle Exposures: the Nairobi Area Traffic Contribution to Air Pollution (NATCAP) Study

    Science.gov (United States)

    Gatari, Michael; Ngo, Nicole; Ndiba, Peter; Kinney, Patrick

    2010-05-01

    Air quality is a serious and worsening problem in the rapidly growing cities of sub-Saharan Africa (SSA), due to rapid urbanization, growing vehicle fleets, changing life styles, limited road infrastructure and land use planning, and high per-vehicle emissions. However, the absence of ambient monitoring data, and particularly urban roadside concentrations of particulate matter in SSA cities, severely limits our ability to assess the real extent of air quality problems. Emitted fine particles by on-road vehicles may be particularly important in SSA cities because large concentrations of poorly maintained vehicles operate in close proximity to commercial and other activities of low-income urban residents. This scenario provokes major air quality concerns and its investigation should be of priority interest to policy makers, city planners and managers, and the affected population. As part of collaboration between Columbia University and the University of Nairobi, a PM2.5 air monitoring study was carried out over two weeks in July 2009. The objectives of the study were 1) to assess average daytime PM2.5 concentrations on a range of Nairobi streets that represent important hot-spots in terms of the joint distribution of traffic, commercial, and resident pedestrian activities, 2) to relate those concentrations to motor vehicle counts, 3) to compare urban street concentrations to urban and rural background levels, and 4) to assess vertical and horizontal dispersion of PM2.5 near roadways. Portable, battery-operated PM2.5 samplers were carried by field teams at each of the five sites (three urban, one commuter highway, and one rural site), each of which operated from 7 AM to 7 PM during 10 weekdays in July 2009. Urban background monitoring took place on a rooftop at the University of Nairobi. Preliminary findings suggest highly elevated PM2.5 concentrations at the urban sites where the greatest pedestrian traffic was observed. These findings underscore the need for air

  3. Dynamics of fine particles during impingement of jets on a body with a needle

    Science.gov (United States)

    Alkhimov*, A. P.; Bedarev, I. A.; Fedorov, A. V.

    2013-07-01

    Numerical simulation of the impingement of a jet of a two-phase mixture of a gas with submicron metal particles on an obstacle with a needle located in front of it is carried out. The structure of a separated flow formed on impingement of a supersonic jet on a body with a needle has been studied. A comparison of various approximations for the law of resistance of spherical particles is made. It is shown that particles whose size exceeds 5 μm practically have a rectilinear trajectory and velocity sufficient for cold gas-dynamical deposition, whereas particles of diameter less than 0.2 μm envelope the separation zone being formed near the needle, and their velocity is much smaller than the critical one.

  4. Evaluation of correlating factors between {sup 238}U concentration measured in fine and course atmospheric particles

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Claudia Marques; Jacomino, Vanusa Maria Feliciano; Barreto, Alberto Avelar; Dias, Vagner Silva, E-mail: cmp@cdtn.b, E-mail: vmfj@cdtn.b, E-mail: aab@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Dias, Fabiana Ferrari, E-mail: fdias@cnen.gov.b [Brazilian Nuclear Energy Commission (CNEN-/MG), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas (LAPOC)

    2009-07-01

    Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 mum aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM{sub 10}), defined as those particles with less than 10 mum aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM{sub 10}, PI{sub 2.5} and PI{sub 1}, as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report {sup 238}U activity concentration results. (author)

  5. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2002-08-15

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO2 control, NOx control, and inorganic fine particle and toxic metal emissions will be determined. Previous research has yielded data on trace metal partitioning for MSS by itself, with natural gas assist, for coal plus MSS combustion together, and for coal alone. We have re-evaluated the inhalation health effects of ash aerosol from combustion of MSS both by itself and also together with coal. We have concluded that ash from the co-combustion of MSS and coal is very much worse from an inhalation health point of view, than ash from either MSS by itself or coal by itself. The reason is that ZnO is not the ''bad actor'' as had been suspected before, but the culprit is, rather, sulfated Zn. The MSS supplies the Zn and the coal supplies the sulfur, and so it is the combination of coal and MSS that makes that process environmentally bad. If MSS is to be burned, it should be burned without coal, in the absence of sulfur.

  6. Development of fine-celled bio-fiber composite foams using physical blowing agents and nano-particles

    Science.gov (United States)

    Guo, Gangjian

    As one of eco-friendly bio-fibers, wood-fiber has been incorporated in plastics to make wood-fiber/plastic composites (WPC) with an increased stiffness, durability and lowered cost. However, these improvements are usually accompanied by loss in the ductility and impact strength of the composites. These shortcomings can be significantly improved by incorporating a fine-cell foam structure in the composites. This thesis presents the development of the foaming technology for the manufacture of fine-cell WPC foams with environmentally benign physical blowing agents (PBAs), and focuses on the elucidation of the fundamental foaming mechanisms and the related issues involved. One critical issue comes from the volatiles evolved from the wood-fiber during high temperature processing. The volatiles, as a blowing agent, can contribute to the foaming process. However, they lead to gross deterioration of the cell structure of WPC foams. The presence of volatiles makes foaming of WPC "a poorly understood black art". With the use of PBAs, a strategy of lowering processing temperature becomes feasible, to suppress the generation of volatiles. A series of PBA-based experiments were designed using a statistical design of experiments (DOE) technique, and were performed to establish the relationship of processing and material variables with the structure of WPC foams. Fundamental foaming behaviors for two different PBAs and two different polymer systems were identified. WPC foams with a fine-cell morphology and a desired density were successfully obtained at the optimized conditions. Another limitation for the wider application of WPC is their flammability. Innovative use of a small amount of nano-clay in WPC significantly improved the flame-retarding property of WPC, and the key issue was to achieve a high degree of exfoliation of nano-particles in the polymer matrix, to achieve a desired flammability reduction. The synergistic effects of nano-particles in foaming of WPC were

  7. 超细颗粒卤化银的制备与稳定性%PREPARATION OF ULTRA-FINE SILVER HALIDE PARTICLES AND THEIR STABILITY

    Institute of Scientific and Technical Information of China (English)

    崔兴品; 岳军

    1999-01-01

    With gelatin or gelatin+PVA as colloid protective medium and under proper reactive condition, ultra-fine silver iodobromide particles with average diameter of about 20 nm and better monodispersity were prepared by direct reaction of silver nitrate with mixture of potassium bromide and potassium iodide. According to TEM data, it was discovered that gelatin+PVA showed stronger colloid protective power for these ultra-fine particles, which restrained particles' coalescence and growth effectively during physical and chemical ripening, so that there was not observable change of particle size and monodispersity to be found. In the case of only gelatin as colloid protective medium to prepare ultra-fine silver iodobromide particles, particles'stability in the process of physical ripening depended on the ratio of gelatin amount to silver content as the preparing reaction. It appears that there exists a critical ratio of gelatin amount to silver content for particles′ stability. When experimental ratio of gelatin amount to silver content in the reaction was over this critical ratio, gelatin can protect ultra-fine particles against coalescence and growth to a considerable degree. On the contrary, the particle size beacme significantly large in the process of physical ripening due to decrease of gelatin protective power if the experimental ratio was lower than this critical ratio.

  8. Inhalation exposure to nanosized and fine TiO2 particles inhibits features of allergic asthma in a murine model

    Directory of Open Access Journals (Sweden)

    Wolff Henrik

    2010-11-01

    Full Text Available Abstract Background Nanotechnology and engineered nanomaterials (ENM are here to stay. Recent evidence suggests that exposure to environmental particulate matter exacerbates symptoms of asthma. In the present study we investigated the modulatory effects of titanium dioxide particle exposure in an experimental allergic asthma. Methods Nonallergic (healthy and ovalbumin-sensitized (asthmatic mice were exposed via inhalation to two different sizes of titanium dioxide particles, nanosized (nTiO2 and fine (fTiO2, for 2 hours a day, three days a week, for four weeks at a concentration of 10 mg/m3. Different endpoints were analysed to evaluate the immunological status of the mice. Results Healthy mice elicited pulmonary neutrophilia accompanied by significantly increased chemokine CXCL5 expression when exposed to nTiO2. Surprisingly, allergic pulmonary inflammation was dramatically suppressed in asthmatic mice which were exposed to nTiO2 or fTiO2 particles - i.e. the levels of leucocytes, cytokines, chemokines and antibodies characteristic to allergic asthma were substantially decreased. Conclusions Our results suggest that repeated airway exposure to TiO2 particles modulates the airway inflammation depending on the immunological status of the exposed mice.

  9. Distributed Lag Analyses of Daily Hospital Admissions and Source-Apportioned Fine Particle Air Pollution

    OpenAIRE

    2010-01-01

    Background Past time-series studies of the health effects of fine particulate matter [aerodynamic diameter ≤ 2.5 μm (PM2.5)] have used chemically nonspecific PM2.5 mass. However, PM2.5 is known to vary in chemical composition with source, and health impacts may vary accordingly. Objective We tested the association between source-specific daily PM2.5 mass and hospital admissions in a time-series investigation that considered both single-lag and distributed-lag models. Methods Daily PM2.5 speci...

  10. Advection, dispersion, and filtration of fine particles within emergent vegetation of the Florida Everglades

    Science.gov (United States)

    Huang, Y.H.; Saiers, J.E.; Harvey, J.W.; Noe, G.B.; Mylon, S.

    2008-01-01

    The movement of particulate matter within wetland surface waters affects nutrient cycling, contaminant mobility, and the evolution of the wetland landscape. Despite the importance of particle transport in influencing wetland form and function, there are few data sets that illuminate, in a quantitative way, the transport behavior of particulate matter within surface waters containing emergent vegetation. We report observations from experiments on the transport of 1 ??m latex microspheres at a wetland field site located in Water Conservation Area 3A of the Florida Everglades. The experiments involved line source injections of particles inside two 4.8-m-long surface water flumes constructed within a transition zone between an Eleocharis slough and Cladium jamaicense ridge and within a Cladium jamaicense ridge. We compared the measurements of particle transport to calculations of two-dimensional advection-dispersion model that accounted for a linear increase in water velocities with elevation above the ground surface. The results of this analysis revealed that particle spreading by longitudinal and vertical dispersion was substantially greater in the ridge than within the transition zone and that particle capture by aquatic vegetation lowered surface water particle concentrations and, at least for the timescale of our experiments, could be represented as an irreversible, first-order kinetics process. We found generally good agreement between our field-based estimates of particle dispersion and water velocity and estimates determined from published theory, suggesting that the advective-dispersive transport of particulate matter within complex wetland environments can be approximated on the basis of measurable properties of the flow and aquatic vegetation. Copyright 2008 by the American Geophysical Union.

  11. Capture Efficiency of Cooking-Related Fine and Ultrafine Particles by Residential Exhaust Hoods

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa M.; Delp, William W.

    2014-06-05

    Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.

  12. Melt Adsorption as a Manufacturing Method for Fine Particles of Wax Matrices without Any Agglomerates.

    Science.gov (United States)

    Shiino, Kai; Fujinami, Yukari; Kimura, Shin-Ichiro; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2017-01-01

    We have focused on melt adsorption as manufacture method of wax matrices to control particles size of granules more easily than melt granulation. The purpose of present study was to investigate the possibility of identifying a hydrophobic material with a low melting point, currently used as a meltable binder of melt granulation, to apply as a novel carrier in melt adsorption. Glyceryl monostearate (GM) and stearic acid (SA) were selected as candidate hydrophobic materials with low melting points. Neusilin US2 (US2), with a particle diameter of around 100 µm was selected as a surface adsorbent, while dibasic calcium phosphate dihydrate (DCPD), was used as a non-adsorbent control to prepare melting granules as a standard for comparison. We prepared granules containing ibuprofen (IBU) by melt adsorption or melt granulation and evaluated the particle size, physical properties and crystallinity of granules. Compared with melt granulation using DCPD, melt adsorption can be performed over a wide range of 14 to 70% for the ratio of molten components. Moreover, the particle size; d50 of obtained granules was 100-200 µm, and these physical properties showed good flowability and roundness. The process of melt adsorption did not affect the crystalline form of IBU. Therefore, the present study has demonstrated for the first time that melt adsorption using a hydrophobic material, GM or SA, has the potential capability to control the particle size of granules and offers the possibility of application as a novel controlled release technique.

  13. Fine ambient particles induce oxidative stress and metal binding genes in human alveolar machrophages

    Science.gov (United States)

    Exposure to ambient pollutant particles (APP) increased respiratory morbidity and mortality. The alveolar macrophages (AMs) are one cell type in the lung directly exposed to APP. Upon contact with APP, AMs are activated and produce reactive oxygen species, but the scope ofthis ox...

  14. Estimates of HVAC filtration efficiency for fine and ultrafine particles of outdoor origin

    Science.gov (United States)

    Azimi, Parham; Zhao, Dan; Stephens, Brent

    2014-12-01

    This work uses 194 outdoor particle size distributions (PSDs) from the literature to estimate single-pass heating, ventilating, and air-conditioning (HVAC) filter removal efficiencies for PM2.5 and ultrafine particles (UFPs: Standard 52.2 does not explicitly account for UFP or PM2.5 removal efficiency, estimates of filtration efficiency for both size fractions increased with increasing MERV. Our results also indicate that outdoor PSD characteristics and assumptions for particle density and typical size-resolved infiltration factors (in the absence of HVAC filtration) do not drastically impact estimates of HVAC filter removal efficiencies for PM2.5. The impact of these factors is greater for UFPs; however, they are also somewhat predictable. Despite these findings, our results also suggest that MERV alone cannot always be used to predict UFP or PM2.5 removal efficiency given the various size-resolved removal efficiencies of different makes and models, particularly for MERV 7 and MERV 12 filters. This information improves knowledge of how the MERV designation relates to PM2.5 and UFP removal efficiency for indoor particles of outdoor origin. Results can be used to simplify indoor air quality modeling efforts and inform standards and guidelines.

  15. Coarse and fine particles but not ultrafine particles in urban air trigger hospital admission for asthma in children

    DEFF Research Database (Denmark)

    Iskandar, Amne; Andersen, Zorana Jovanovic; Bønnelykke, Klaus;

    2012-01-01

    BackgroundShort-term exposure to air pollution can trigger hospital admissions for asthma in children, but it is not known which components of air pollution are most important. There are no available studies on the particular effect of ultrafine particles (UFPs) on paediatric admissions for asthma......(x)) or nitrogen dioxide (NO(2)); and (2) infants are more susceptible to the effects of exposure to air pollution than older children.MethodDaily counts of admissions for asthma in children aged 0-18 years to hospitals located within a 15 km radius of the central fixed background urban air pollution measurement...... station in Copenhagen between 2001 and 2008 were extracted from the Danish National Patient Registry. A time-stratified case crossover design was applied and data were analysed using conditional logistic regression to estimate the effect of air pollution on asthma admissions.ResultsA significant...

  16. Performance analysis of a new positron camera geometry for high speed, fine particle tracking

    Science.gov (United States)

    Sovechles, J. M.; Boucher, D.; Pax, R.; Leadbeater, T.; Sasmito, A. P.; Waters, K. E.

    2017-09-01

    A new positron camera arrangement was assembled using 16 ECAT951 modular detector blocks. A closely packed, cross pattern arrangement was selected to produce a highly sensitive cylindrical region for tracking particles with low activities and high speeds. To determine the capabilities of this system a comprehensive analysis of the tracking performance was conducted to determine the 3D location error and location frequency as a function of tracer activity and speed. The 3D error was found to range from 0.54 mm for a stationary particle, consistent for all tracer activities, up to 4.33 mm for a tracer with an activity of 3 MBq and a speed of 4 m · s-1. For lower activity tracers (sensitive to increases in speed, increasing to 28 mm (at 4 m · s-1), indicating that at these conditions a reliable trajectory is not possible. These results expanded on, but correlated well with, previous literature that only contained location errors for tracer speeds up to 1.5 m · s-1. The camera was also used to track directly activated mineral particles inside a two-inch hydrocyclone and a 142 mm diameter flotation cell. A detailed trajectory, inside the hydrocyclone, of a  -212  +  106 µm (10-1 MBq) quartz particle displayed the expected spiralling motion towards the apex. This was the first time a mineral particle of this size had been successfully traced within a hydrocyclone, however more work is required to develop detailed velocity fields.

  17. NEXAFS microscopy studies of the association of hydrocarbon thin films with fine clay particles

    Energy Technology Data Exchange (ETDEWEB)

    Covelli, Danielle [Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N 5C9 (Canada); Hernandez-Cruz, Daniel [Brockhouse Institute for Material Research, McMaster University, Hamilton, ON, L8S 4M1 (Canada); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Haines, Brian M. [Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N 5C9 (Canada); Munoz, Vincente; Omotoso, Oladipo; Mikula, Randy [CANMET Energy Technology Centre Natural Resources Canada, Devon, AB, T9G 1A8 (Canada); Urquhart, Stephen [Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N 5C9 (Canada)], E-mail: stephen.urquhart@usask.ca

    2009-06-15

    The nature of organic species associated with clay minerals plays a significant role in several processes, from hydrocarbon recovery in oil sands to contaminated soil remediation and water treatment. In this work, we address the use of scanning transmission X-ray microscopy (STXM) in conjunction with near edge X-ray absorption fine structure (NEXAFS) spectroscopy to study the microstructure and chemistry of organic-clay associations in situ. A model system based on methylene blue and illite is used to explore the sensitivity of NEXAFS microscopy to these interactions, and to identify and resolve experimental challenges in these measurements. We find that sample contamination from X-ray induced photodeposition is a significant problem in STXM microscopy, but also that this problem can be substantially reduced with a liquid nitrogen cooled anticontaminator. With appropriate sample preparation and experimental procedures, we find that STXM microscopy is sensitive to thin carbon adsorbates on clay surfaces.

  18. Formation of fine particles in co-combustion of coal and solid recovered fuel in a pulverized coal-fired power station

    DEFF Research Database (Denmark)

    Wu, Hao; Pedersen, Anne Juul; Glarborg, Peter

    2011-01-01

    Fine particles formed from combustion of a bituminous coal and co-combustion of coal with 7 th% (thermal percentage) solid recovered fuel (SRF) in a pulverized coal-fired power plant were sampled and characterized in this study. The particles from dedicated coal combustion and co-combustion both...... appear to be an important formation mechanism. The elemental composition of the particles from coal combustion showed that S and Ca were significantly enriched in ultrafine particles and P was also enriched considerably. However, compared with supermicron particles, the contents of Al, Si and K were...

  19. Compositions of coarse and fine particles in martian soils at gale: A window into the production of soils

    Science.gov (United States)

    Cousin, A.; Meslin, P. Y.; Wiens, R. C.; Rapin, W.; Mangold, N.; Fabre, C.; Gasnault, O.; Forni, O.; Tokar, R.; Ollila, A.; Schröder, S.; Lasue, J.; Maurice, S.; Sautter, V.; Newsom, H.; Vaniman, D.; Le Mouélic, S.; Dyar, D.; Berger, G.; Blaney, D.; Nachon, M.; Dromart, G.; Lanza, N.; Clark, B.; Clegg, S.; Goetz, W.; Berger, J.; Barraclough, B.; Delapp, D.

    2015-03-01

    The ChemCam instrument onboard the Curiosity rover provides for the first time an opportunity to study martian soils at a sub-millimeter resolution. In this work, we analyzed 24 soil targets probed by ChemCam during the first 250 sols on Mars. Using the depth profile capability of the ChemCam LIBS (Laser-Induced Breakdown Spectroscopy) technique, we found that 45% of the soils contained coarse grains (>500 μm). Three distinct clusters have been detected: Cluster 1 shows a low SiO2 content; Cluster 2 corresponds to coarse grains with a felsic composition, whereas Cluster 3 presents a typical basaltic composition. Coarse grains from Cluster 2 have been mostly observed exposed in the vicinity of the landing site, whereas coarse grains from Clusters 1 and 3 have been detected mostly buried, and were found all along the rover traverse. The possible origin of these coarse grains was investigated. Felsic (Cluster 2) coarse grains have the same origin as the felsic rocks encountered near the landing site, whereas the origin of the coarse grains from Clusters 1 and 3 seems to be more global. Fine-grained soils (particle size < laser beam diameter which is between 300 and 500 μm) show a homogeneous composition all along the traverse, different from the composition of the rocks encountered at Gale. Although they contain a certain amount of hydrated amorphous component depleted in SiO2, possibly present as a surface coating, their overall chemical homogeneity and their close-to-basaltic composition suggest limited, or isochemical alteration, and a limited interaction with liquid water. Fine particles and coarse grains from Cluster 1 have a similar composition, and the former could derive from weathering of the latter. Overall martian soils have a bulk composition between that of fine particles and coarse grains. This work shows that the ChemCam instrument provides a means to study the variability of soil composition at a scale not achievable by bulk chemical analyses.

  20. The heavy metal partition in size-fractions of the fine particles in agricultural soils contaminated by waste water and smelter dust

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibo, E-mail: hbzhang@yic.ac.cn [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Luo, Yongming, E-mail: ymluo@yic.ac.cn [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Makino, Tomoyuki [National Institute for Agro-Environmental Sciences, Tsukuba 3058604 (Japan); Wu, Longhua [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Nanzyo, Masami [Tohoku University, Sendai 9808576 (Japan)

    2013-03-15

    Highlights: ► A continuous flow ultra-centrifugation method has been developed to obtain fine particles from polluted agricultural soil. ► Pollution source affected the heavy metal fractionation in size-fractions by changing soil particle properties. ► The iron oxides affected the distribution of lead species more than other metals in the smelter dust polluted particles. -- Abstract: The partitioning of pollutant in the size-fractions of fine particles is particularly important to its migration and bioavailability in soil environment. However, the impact of pollution sources on the partitioning was seldom addressed in the previous studies. In this study, the method of continuous flow ultra-centrifugation was developed to separate three size fractions (<1 μm, <0.6 μm and <0.2 μm) of the submicron particles from the soil polluted by wastewater and smelter dust respectively. The mineralogy and physicochemical properties of each size-fraction were characterized by X-ray diffraction, transmission electron microscope etc. Total content of the polluted metals and their chemical speciation were measured. A higher enrichment factor of the metals in the fractions of <1 μm or less were observed in the soil contaminated by wastewater than by smelter dust. The organic substance in the wastewater and calcite from lime application were assumed to play an important role in the metal accumulation in the fine particles of the wastewater polluted soil. While the metal accumulation in the fine particles of the smelter dust polluted soil is mainly associated with Mn oxides. Cadmium speciation in both soils is dominated by dilute acid soluble form and lead speciation in the smelter dust polluted soil is dominated by reducible form in all particles. This implied that the polluted soils might be a high risk to human health and ecosystem due to the high bioaccessblity of the metals as well as the mobility of the fine particles in soil.

  1. Sources of organic compounds in fine soil and sand particles during winter in the metropolitan area of Riyadh, Saudi Arabia.

    Science.gov (United States)

    Rushdi, Ahmed I; Al-Mutlaq, Khalid; Simoneit, Bernd R T

    2005-11-01

    Major advances have been made in molecular marker analysis to distinguish between natural and anthropogenic organic matter inputs to the atmosphere. Resuspension of soil and sand by wind is one of the major mechanisms that produces particle dusts in the atmosphere. Soil and sand samples from the Riyadh area were collected in winter 2002, sieved to remove coarse particles and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The total extracts were analyzed by gas chromatography-mass spectrometry in order to characterize the contents and identify the potential sources of the organic components. The major organic compounds of these extracts were derived from natural biogenic and anthropogenic sources. Organic compounds from natural sources, mainly vegetation, were major in samples from outside the city of Riyadh and included n-alkanes, n-alkanoic acids, n- alkanols, methyl alkanoates, and sterols. Anthropogenic inputs were significant in the fine particles of soil and sand samples collected from populated areas of the city. They consisted mainly of n-alkanes, hopanes, UCM (from vehicular emissions), and plasticizers (from discarded plastics, e.g., shopping bags). Carbohydrates had high concentrations in all samples and indicate sources from decomposed cellulose fibers and/or the presence of viable microbiota such as bacteria and fungi.

  2. Study on Metallized Reduction and Magnetic Separation of Iron from Fine Particles of High Iron Bauxite Ore

    Science.gov (United States)

    Liu, Zheng-Gen; Chu, Man-Sheng; Wang, Zheng; Zhao, Wei; Tang, Jue

    2017-01-01

    High iron bauxite ore is a typical unmanageable polyparagenetic resource and owns high comprehensive utilization value. Separation of iron from fine particles of high iron bauxite ore by the process of metallized reduction and magnetic dressing was researched systemically. The effect of magnetic field intensity, reduction temperature, reduction time, mole ratio of fixed carbon to reducible oxygen (FC/O) and ore particles size on separation indexes was researched. The results show that, with the conditions of reduction temperature of 1,400 °C, reduction time of 180 min, FC/O of 2.0, ore particle size of -2.0 mm and magnetic field intensity of 40 KA/m, about 89.24 % of the iron could be removed from high iron bauxite ore as metallic iron. Meanwhile, 86.09 % of the aluminum is stayed in non-magnetic fraction as alumina. However, the formation of hercynite (FeAl2O4) limits the reduction rate of iron oxides to metallic iron. The lower reduction conditions and higher recovery ratio of iron could be achieved with adopting ore-coal composite agglomerates or adding catalyst.

  3. 路博润收购Particle Sciences

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    路博润企业在其官网宣布收购Particle Sciences,后者是领先的合同药物研发生产机构,提供复杂药品交付方案从构思、分析到制定的综合型服务。其总部位于宾夕法尼亚州伯利恒。此次收购进一步拓展了路博润Life Sciences的制药研发能力,由此可为市场提供不同剂型药物传输解决方案。路博润Life Sciences副总裁兼总经理Deb Langer说:"在Particle Sciences之外近期我们还收购了Vesta,这样,就能为客户提供一套完整的解决方案,这也是目前行业内最全面的解决方案之一。此外,有了Particle Sciences的加入,我们得以从核心聚合物化学转入新型可移植皮肤药物传输系统的定制化解决方案。"近年来,路博润Life Sciences凭借其创新产品、先进装置以及并购联合获得了显著发展。Vesta先进的制药技术、

  4. Flocculation of fine fluorite particles with Corynebacterium xerosis and commercial long chain polymers

    Directory of Open Access Journals (Sweden)

    Rigo Lisandra N.

    2002-01-01

    Full Text Available This work aimed to study, comparatively, the flocculation of fluorite particles with Corynebacterium xerosis cells and three commercial long chain polymers. Best flocculation results were obtained with cells of C. xerosis and with an anionic polyacrylamide. Both were effective in solids removal and water clarification, although flocculation with C. xerosis cells requires a higher dosage of reagent per mass unit of processed ore.

  5. Analysis on thermophoretic deposit of fine particle on water wall of 10 MW high temperature gas-cooled reactor

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tao; YANG Rui-Chang; JIA Dou-Nan

    2005-01-01

    The water wall is an important part of the passive natural circulation residual heat removal system in a high temperature gas-cooled reactor. The maximum temperatures of the pressure shell and the water wall are calculated using annular vertical closed cavity model. Fine particles can deposit on the water wall due to the thermophore sis effect. This deposit can affect heat transfer. The thermophoretic deposit efficiency is calculated by using Batch and Shen's formula fitted for both laminar flow and turbulent flow. The calculated results indicate that natural convection is turbulent in the closed cavity. The transient thermophoretic deposit efficiency rises with the increase of the pressure shell's temperature. Its maximum value is 14%.

  6. An investigation into the effect of fine lactose particles on the fluidization behaviour and aerosolization performance of carrier-based dry powder inhaler formulations.

    Science.gov (United States)

    Kinnunen, Hanne; Hebbink, Gerald; Peters, Harry; Shur, Jagdeep; Price, Robert

    2014-08-01

    The effect of milled and micronized lactose fines on the fluidization and in vitro aerosolization properties of dry powder inhaler (DPI) formulations was investigated, and the suitability of static and dynamic methods for characterizing general powder flow properties of these blends was assessed. Lactose carrier pre-blends were prepared by adding different lactose fines (Lactohale® (LH) 300, 230 and 210) with coarse carrier lactose (Lactohale100) at 2.5, 5, 10 and 20 wt% concentrations. Powder flow properties of lactose pre-blends were characterized using the Freeman Technology FT4 and Schulze RST-XS ring shear tester. A strong correlation was found between the basic flow energy (BFENorm) measured using the Freeman FT4 Rheometer and the flowability number (ffc) measured on Schulze RST-XS. These data indicate that both static and dynamic methods are suitable for characterizing general powder flow properties of lactose carriers. Increasing concentration of fines corresponded with an increase in the normalized fluidization energy (FENorm). The inclusion of fine particles of lactose resulted in a significant (p lactose containing up to 10 wt% LH300. A similar trend was found for the milled lactose grades LH230 and LH210. However, the increase in FENorm upon addition of milled fines only corresponded to a very slight improvement in the performance. These data suggest that whilst the fluidization energy correlated with fine particle delivery, this relationship is specific to lactose grades of similar particle size.

  7. Intraurban Variation of Fine Particle Elemental Concentrations in New York City.

    Science.gov (United States)

    Ito, Kazuhiko; Johnson, Sarah; Kheirbek, Iyad; Clougherty, Jane; Pezeshki, Grant; Ross, Zev; Eisl, Holger; Matte, Thomas D

    2016-07-19

    Few past studies have collected and analyzed within-city variation of fine particulate matter (PM2.5) elements. We developed land-use regression (LUR) models to characterize spatial variation of 15 PM2.5 elements collected at 150 street-level locations in New York City during December 2008-November 2009: aluminum, bromine, calcium, copper, iron, potassium, manganese, sodium, nickel, lead, sulfur, silicon, titanium, vanadium, and zinc. Summer- and winter-only data available at 99 locations in the subsequent 3 years, up to November 2012, were analyzed to examine variation of LUR results across years. Spatial variation of each element was modeled in LUR including six major emission indicators: boilers burning residual oil; traffic density; industrial structures; construction/demolition (these four indicators in buffers of 50 to 1000 m), commercial cooking based on a dispersion model; and ship traffic based on inverse distance to navigation path weighted by associated port berth volume. All the elements except sodium were associated with at least one source, with R(2) ranging from 0.2 to 0.8. Strong source-element associations, persistent across years, were found for residual oil burning (nickel, zinc), near-road traffic (copper, iron, and titanium), and ship traffic (vanadium). These emission source indicators were also significant and consistent predictors of PM2.5 concentrations across years.

  8. The ozonolysis of primary aliphatic amines in single and multicomponent fine particles

    Directory of Open Access Journals (Sweden)

    J. Zahardis

    2007-10-01

    Full Text Available The oxidative processing by ozone of the particulate amines octadecylamine (ODA and hexadecylamine (HDA is reported. Ozonolysis of these amines resulted in strong NO2 and NO3 ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitro alkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3(HNO3. For ozonized mixed particles containing ODA or HDA + oleic acid (OL, with pO3≥3×10−7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines and stabilized Criegee intermediates (SCI or secondary ozonides (for amides from the fatty acid. The routes to amides via SCI and/or secondary ozonides was shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s. This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g. NO2, NO3, formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

  9. Availability and bioaccessibility of metals in fine particles of some urban soils.

    Science.gov (United States)

    Madrid, F; Biasioli, M; Ajmone-Marsan, F

    2008-07-01

    Metals in urban soils might be transferred to humans via ingestion, dermal contact, or breathing, especially to children due to the "hand to mouth" activity during outdoor activities in playground and recreational areas. This involuntary soil ingestion depends on soil adherence to skin; it is known that the adhesion process tends to exclude particles greater than 50 microm, so the fraction below this diameter would be the most dangerous for health. The aim of this work was to study the "availability", estimated by the EDTA extraction, and "oral bioaccessibility", estimated by the Simple Bioaccessibility Extraction Test (SBET), of several metals in urban soils of two European cities (Sevilla and Torino), as related to the soil particle size distribution. Torino and Sevilla showed different levels of metal contents, availability, and bioaccessibility. In Torino, the finer particles showed metal enrichment of Cu, Zn, and, to a lesser extent, Pb, whereas in Sevilla, all of the studied metals showed this enrichment compared to the whole soils. The whole soil cannot be used as a good general indicator of the bioaccessibility of metals in the finest fractions of the soil. Metal availability was higher in the clay fraction (soils in both cities, and principal component analysis shows that availability is especially due to this fraction. In contrast, Cu and Pb bioaccessibility in the clay fraction seems to be slightly lower than, or comparable to, all of the other fractions and the whole soil. Bioaccessibility of Cr and Ni is clearly greater in the coarser fractions of Sevilla than those of Torino, despite the considerably greater total contents of both metals in the latter city. Adsorbed metal forms are assumed to be preferentially responsible for metals released by EDTA. A different origin is attributed to bioaccessible metal forms. Anthropic influence seems more important in determining metal availability and bioaccessibility in urban soils of both cities than the

  10. Spatial variability of fine and coarse particle composition and sources in Cyprus

    Science.gov (United States)

    Achilleos, Souzana; Wolfson, Jack M.; Ferguson, Stephen T.; Kang, Choong-Min; Hadjimitsis, Diofantos G.; Hadjicharalambous, Marios; Achilleos, Constantia; Christodoulou, Andri; Nisanzti, Argyro; Papoutsa, Christiana; Themistocleous, Kyriacos; Athanasatos, Spyros; Perdikou, Skevi; Koutrakis, Petros

    2016-03-01

    Southern and Eastern European countries exceed WHO and EU air quality standards very often, and are influenced by both local and external sources from Europe, Asia and Africa. However, there are limited data on particle composition and source profiles. We collected PM2.5 and PM10 samples (particulate matter with aerodynamic diameter less than 2.5 and 10 μm, respectively) in four cities in Cyprus using Harvard Impactors. Measurements were conducted between January 2012 and January 2013. We analyzed these samples for mass concentration and chemical composition, and conducted a source apportionment analysis using Positive Matrix Factorization (PMF). All sites complied with PM2.5 and PM10 WHO daily standards for most of the days. As in other Eastern European countries, we found higher sulfate contribution and less organic carbon than in the Western and central Europe. For PM2.5, seven source types were identified including regional sulfur, traffic emissions, biomass, re-suspended soil, oil combustion, road dust, and sea salt. In all four sites, regional sulfur was the predominant source (> 30%). High inter-site correlations were observed for both PM2.5 component concentrations and source contributions, may be because a large fraction of PM2.5 is transported. Finally, for PM10 -2.5 (coarse particles with aerodynamic diameter between 2.5 and 10 μm) three sources were identified, which include road dust, soil, and sea salt. Significant inter-site correlations were also observed for coarse particles. All dust storm samples, except one, had PM levels below the daily standard. However, mineral dust, defined as the total mass of crustal metal oxides, increased up to ten times during the dust events.

  11. Comprehensive characterization of ambient nanoparticles collected near an industrial science park: Particle size distributions and relationships with environmental factors

    Institute of Scientific and Technical Information of China (English)

    Yuhjeen Huang; Lingyen Hsu; Yunghsun Chang

    2011-01-01

    We investigated the characteristics of ambient particles and their relationships with various environmental factors,including gaseous pollutants (CH4,non-methane hydrocarbons (NMHC),total hydrocarbons (THC),NOx,CO,SO2),meteorological parameters (humidity,temperature),and time (day/night,workday/weekend).We used an electrical low-pressure cascade impactor to measure the number and size distributions of ambient particles (0.007-10 μm) that were collected approximately 1 km northwest of Hsinchu Science Park in Talwan between February and May 2007.The number concentrations of particles were enhanced through photochemical reactions during the day.In addition,high traffic flow during workdays increased the formation of particulates.Except for SO2,all of the gaseous pollutants we studied (CH4,NMHC,THC,NOx,CO) correlated positively with the total number concentrations of ambient particles during daytime,indicating that they might contribute to the particulate burden.The poorer relationship between the SO2 level and the total number concentration of particles suggests that SO2 might participate indirectly in the nucleation process during particle formation,The high enrichment factors for Zn,Pb,Cu,and Mn,which mostly comprised the ultrafine particles (diameter:< 0.1 μm) and fine particles (diameter:0.1-1 μm),presumably arose from emissions from traffic and high technology factories.Heterogeneous reactions on solid particles might play a role in the removal of SOx and NOx from the atmosphere.Sulfides and nitrides can further react with these local pollutants,forming specific Cu-containing compounds:CuO (39%),CuSO4 (34%),and Cu(NO3)2 (27%),within the ambient particles in this industrial area.

  12. HONO and Inorganic Fine Particle Composition in Typical Monsoon Region with Intensive Anthropogenic Emission: In-situ Observations and Source Identification.

    Science.gov (United States)

    Xie, Y.; Nie, W.; Ding, A.; Huang, X.

    2015-12-01

    Yangtze River Delta (YRD) is one of the most typical monsoon area with probably the most largest population intensity in the world. With sharply economic development and the large anthropogenic emissions, fine particle pollution have been one of the major air quality problem and may further have impact on the climate system. Though a lot of control policy (sulfur emission have been decreasing from 2007) have been conducted in the region, studies showed the sulfate in fine particles still take major fraction as the nitrate from nitrogen oxides increased significantly. In this study, the role of inorganic chemical compositions in fine particles was investigated with two years in-situ observation. Sulfate and Nitrate contribute to fine particle mass equally in general, but sulfate contributes more during summer and nitrate played more important role in winter. Using lagrangian dispersion backward modeling and source contribution clustering method, the impact of airmass coming from different source region (industrial, dust, biogenic emissions, etc) on fine particle inorganic compositions were discussed. Furthermore, we found two unique cases showing in-situ implications for sulfate formation by nitrogen dioxide oxidation mechanisms. It was showed that the mixing of anthropogenic pollutants with long-range transported mineral dust and biomass burning plume would enhance the sulfate formation by different chemistry mechanisms. This study focus on the complex aspects of fine particle formation in airmasses from different source regions: . It highlights the effect of NOx in enhancing the atmospheric oxidization capacity and indicates a potentially very important impact of increasing NOx on air pollution formation and regional climate change in East Asia.

  13. [Pollutions of indoor fine particles in four types of public places and the influencing factors].

    Science.gov (United States)

    Liu, Bo; Deng, Fu-rong; Guo, Xin-biao; Yang, Dong-mei; Teng, Xiu-quan; Zheng, Xu; Gao, Jing; Dong, Jing; Wu, Shao-wei

    2009-08-01

    To study the levels of pollutions caused by fine particulate matter (PM(2.5)) in the public places and investigate the possible influencing factors. A total of 20 public places in four types such as rest room in bath center, restaurant, karaoke bars and cyber cafe in Tongzhou district in Beijing were chosen in this study; indoor and outdoor PM(2.5) was monitored by TSI sidepak AM510. Data under varying conditions were collected and analyzed, such as doors or windows or mechanical ventilation devices being opened, rooms cramped with people and smoking. The average concentration of indoor PM(2.5) in 20 public places was (334.6 +/- 386.3) microg/m(3), ranging from 6 microg/m(3) to 1956 microg/m(3); while in bath center, restaurant, karaoke bars and cyber cafe were (116.9 +/- 100.1)microg/m(3), (317.9 +/- 235.3) microg/m(3), (750.6 +/- 521.6)microg/m(3) and (157.5 +/- 98.5) microg/m(3) respectively. The concentrations of PM(2.5) in restaurant (compared with bath center: Z = -10.785, P 1.5) points; r = 0.667, F = 14.442, P 1.556, t = 3.760, P = 0.007] when ventilation (score > 2) was relatively good. The number of smokers per cube meters (14.7 x 10(-3)) became the major influence factor when the ventilation score

  14. Surface area of particle administered versus mass in determining the pulmonary toxicity of ultrafine and fine carbon black: comparison to ultrafine titanium dioxide

    Directory of Open Access Journals (Sweden)

    Sager Tina M

    2009-05-01

    Full Text Available Abstract Background Nanoparticles are characterized by having a high surface area per mass. Particulate surface area has been reported to play an important role in determining the biological activity of nanoparticles. However, recent reports have questioned this relationship. This study was conducted to determine whether mass of particles or surface area of particles is the more appropriate dose metric for pulmonary toxicity studies. In this study, rats were exposed by intratracheal instillation to various doses of ultrafine and fine carbon black. At 1, 7, or 42 days post-exposure, inflammatory and cytotoxic potential of each particle type was compared on both a mass dosage (mg/rat as well as an equal surface area dosage (cm2 of particles per cm2 of alveolar epithelium. In an additional study, the pulmonary responses to instillation of ultrafine carbon black were compared to equivalent particle surface area doses of ultrafine titanium dioxide. Results Ultrafine carbon black particles caused a dose dependent but transient inflammatory and cytotoxic response. On a mass basis, these responses were significantly (65 fold greater than those for fine sized carbon black. However, when doses were equalized based on surface area of particles given, the ultrafine carbon black particles were only slightly (non-significantly more inflammogenic and cytotoxic compared to the fine sized carbon black. At one day post-exposure, inflammatory potencies of the ultrafine carbon black and ultrafine titanium dioxide particles were similar. However, while the pulmonary reaction to ultrafine carbon black resolved with time, the inflammatory effects of ultrafine titanium dioxide were more persistent over a 42 day post-exposure period. Conclusion These results indicate that for low toxicity low solubility materials, surface area of particles administered rather than mass burden of particles may be a more appropriate dose metric for pulmonary toxicity studies. In addition

  15. Fine-Tuning Two-Particle Interferometry Effects from Opacity and Temperature Gradients in the Source

    CERN Document Server

    Tomasik, Boris; Tomasik, Boris; Heinz, Ulrich

    1998-01-01

    A comprehensive model study of Bose-Einstein correlation radii in heavy ion collisions is presented. The starting point is a longitudinally and transversally expanding fireball, represented at freeze-out by an azimuthally symmetric emission function. The freeze-out temperature is allowed to feature transverse and temporal gradients. Their effects on the correlation radii are studied. In particular, we evaluate numerically their dependence on the transverse mass of the particle pairs and check a recent suggestion, based on analytical approximations, that for certain reasonable source parameters all three correlation radii satisfy simultaneously a 1/\\sqrt{M_\\perp} scaling. We also investigate quantitatively how the correlation radii are affected if the source becomes ``opaque''. We find a strong sensitivity to opaqueness for the temporal radius parameter R_0 in the YKP parametrization. A qualitative comparison with preliminary data from 158 A GeV/c Pb+Pb collisions at CERN indicates that the source is not opaqu...

  16. Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

    1997-03-01

    The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

  17. Influences of fireworks on chemical characteristics of atmospheric fine and coarse particles during Taiwan's Lantern Festival

    Science.gov (United States)

    Tsai, Hsieh-Hung; Chien, Li-Hsing; Yuan, Chung-Shin; Lin, Yuan-Chung; Jen, Yi-Hsiu; Ie, Iau-Ren

    2012-12-01

    In recent years, the celebration activities of various folk-custom festivals have been getting more and more attention from the citizens in Taiwan. Festivities throughout the whole island are traditionally accompanied by loud and brightly colored firework displays. Among these activities, the firework displays during Taiwan's Lantern Festival in Kaohsiung harbor is one of the largest festivals in Taiwan each year. Therefore, it is of importance to investigate the influence of fireworks displays on the ambient air quality during the Taiwan's Lantern Festival. Field measurements of atmospheric particulate matter (PM) were conducted on February 9th-11th, 2009 during Taiwan's Lantern Festival in Kaohsiung City. Moreover, three kinds of fireworks powders obtained from the same manufacturing factory producing Kaohsiung Lantern Festival fireworks were burned in a self-designed combustion chamber to determine the physicochemical properties of the fireworks' particles and to establish the source profile of firework burning. Several metallic elements of PM during the firework display periods were notably higher than those during the non-firework periods. The concentrations of Mg, K, Pb, and Sr in PM2.5 during the firework periods were 10 times higher than those during the non-firework periods. Additionally, the Cl-/Na+ ratio was approximately 3 during the firework display periods as Cl- came from the chlorine content of the firework powder. Moreover, the OC/EC ratio increased up to 2.8. Results obtained from PCA and CMB receptor modeling showed that major sources of atmospheric particles during the firework display periods in Kaohsiung harbor were fireworks, vehicular exhausts, soil dusts and marine sprays. Particularly, on February 10th, the firework displays contributed approximately 25.2% and 16.6% of PM10 at two downwind sampling sites, respectively.

  18. The heavy metal partition in size-fractions of the fine particles in agricultural soils contaminated by waste water and smelter dust.

    Science.gov (United States)

    Zhang, Haibo; Luo, Yongming; Makino, Tomoyuki; Wu, Longhua; Nanzyo, Masami

    2013-03-15

    The partitioning of pollutant in the size-fractions of fine particles is particularly important to its migration and bioavailability in soil environment. However, the impact of pollution sources on the partitioning was seldom addressed in the previous studies. In this study, the method of continuous flow ultra-centrifugation was developed to separate three size fractions (dust respectively. The mineralogy and physicochemical properties of each size-fraction were characterized by X-ray diffraction, transmission electron microscope etc. Total content of the polluted metals and their chemical speciation were measured. A higher enrichment factor of the metals in the fractions of dust. The organic substance in the wastewater and calcite from lime application were assumed to play an important role in the metal accumulation in the fine particles of the wastewater polluted soil. While the metal accumulation in the fine particles of the smelter dust polluted soil is mainly associated with Mn oxides. Cadmium speciation in both soils is dominated by dilute acid soluble form and lead speciation in the smelter dust polluted soil is dominated by reducible form in all particles. This implied that the polluted soils might be a high risk to human health and ecosystem due to the high bioaccessibility of the metals as well as the mobility of the fine particles in soil.

  19. Impact of aerosol-meteorology interactions on fine particle pollution during China’s severe haze episode in January 2013

    Science.gov (United States)

    Wang, Jiandong; Wang, Shuxiao; Jiang, Jingkun; Ding, Aijun; Zheng, Mei; Zhao, Bin; Wong, David C.; Zhou, Wei; Zheng, Guangjie; Wang, Long; Pleim, Jonathan E.; Hao, Jiming

    2014-09-01

    In January 2013, a severe regional haze occurred over the North China Plain. An online-coupled meteorology-chemistry model was employed to simulate the impacts of aerosol-meteorology interactions on fine particles (PM2.5) pollution during this haze episode. The response of PM2.5 to meteorology change constituted a feedback loop whereby planetary boundary layer (PBL) dynamics amplified the initial perturbation of PM2.5. High PM2.5 concentrations caused a decrease of surface solar radiation. The maximal decrease in daily average solar radiation reached 53% in Beijing, thereby leading to a more stable PBL. The peak PBL height in Beijing decreased from 690 m to 590 m when the aerosol extinction was considered. Enhanced PBL stability suppressed the dispersion of air pollutants, and resulted in higher PM2.5 concentrations. The maximal increase of PM2.5 concentrations reached 140 μg m-3 in Beijing. During most PM2.5 episodes, primary and secondary particles increased simultaneously. These results imply that the aerosol-radiation interactions played an important role in the haze episode in January 2013.

  20. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

    Science.gov (United States)

    Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng

    2014-01-01

    Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm) and M. galloprovincialis (shell height: 4.43 ± 0.98 cm) was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1) • d(-1), respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P aquaculture wastewater, and simultaneously yield value-added biological products.

  1. On the role of the fine structure constant in the alpha/beta rule for calculation of particle masses

    Energy Technology Data Exchange (ETDEWEB)

    Greulich, Karl Otto [Fritz Lipmann Institut, Beutenbergstr.11, 07745 Jena (Germany)

    2016-07-01

    The masses of essentially all elementary particles are given almost exactly by the α/β rule (K.O.Greulich, Spring meeting 2014 German Phys Society T 99.4), i.e. particle masses depend on the fine structure (Sommerfeld constant α 1/137). This is somewhat surprising since alpha is rather known as a spectroscopic constant than as a mass ratio. One key to understand this is the observation that the Bohr energy is exactly the 1/α-fold of the ionization energy of the hydrogen atom (Rydberg energy, 13.6 eV). Thereby the Bohr energy is the de Broglie energy of the electron in the ground state (on the Bohr radius). A second mass or energy ratio, the ratio between the energy at rest of the electron and the Bohr energy can be derived analytically to be α{sup -2}. Both results together suggest a general dependence of rest energies or rest masses on α. Simply by the hypothesis that this observation can be extrapolated to higher values of n, the α/β rule follows immediately. Only the beta (1 or 1836.12) term has to be added empirically.

  2. The influence of nano-scale second-phase particles on deformation of fine grained calcite mylonites

    Science.gov (United States)

    Herwegh, Marco; Kunze, Karsten

    2002-09-01

    Grey and white carbonate mylonites were collected along thrust planes of the Helvetic Alps. They are characterised by very small grain sizes and non-random grain shape (SPO) and crystallographic preferred orientation (CPO). Presumably they deformed in the field of grain size sensitive flow by recrystallisation accommodated intracrystalline deformation in combination with granular flow. Both mylonites show a similar mean grain size, but in the grey mylonites the grain size range is larger, the grain shapes are more elongate and the dynamically recrystallised calcite grains are more often twinned. Grey mylonites have an oblique CPO, while the CPO in white mylonites is symmetric with respect to the shear plane. Combustion analysis and TEM investigations revealed that grey mylonites contain a higher amount of highly structured kerogens with particle sizes of a few tens of nanometers, which are finely dispersed at the grain boundaries. During deformation of the rock, nano-scale particles reduced the migration velocity of grain boundaries by Zener drag resulting in slower recrystallisation rates of the calcite aggregate. In the grey mylonites, more strain increments were accommodated by individual grains before they became refreshed by dynamic recrystallisation than in white mylonites, where grain boundary migration was less hindered and recrystallisation cycles were faster. Consequently, grey mylonites represent 'deformation' microfabrics while white mylonites are characterised by 'recrystallisation' microfabrics. Field geologists must utilise this different deformation behavior when applying the obliquity in CPO and SPO of the respective mylonites as reliable shear sense indicators.

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

    Science.gov (United States)

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

    2015-02-01

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

  4. Effect of feeding fine maize particles on the reticular pH, milk yield and composition of dairy cows.

    Science.gov (United States)

    De Nardi, R; Marchesini, G; Stefani, A-L; Barberio, A; Andrighetto, I; Segato, S

    2014-06-01

    The particle size of cereal grains has been found to modulate the rate of passage from the rumen and the digestibility of starch and neutral detergent fibre (NDF), but few studies have examined its impact on reticular pH. The study aimed to evaluate the effect of feeding finely ground maize on the risk of ruminal acidosis, milk yield and composition. Twelve Holstein-Friesian cows were assigned to one of two experimental groups and fed according to a cross-over design. Diets were isoenergetic and isonitrogenous and were characterised by the same NDF and ADF, differing only in maize particle size. In the control diet (Ct), the maize meal was ground to 1.0 mm, whereas in the experimental diet, it was finely ground (Fg) to 0.5 mm. The pH and temperature of the reticulum were continuously measured in eight cows throughout the trial using indwelling sensors. Dry matter intake was higher in cows offered Fg diet than in Ct (19.0 vs. 20.3 kg/day; p = 0.067). However, milk yield (p = 0.855) and the 3.5% fat-corrected milk (FCM) (p = 0.724) did not show any differences between the diets. Casein (2.48 vs. 2.57%; p = 0.035) and crude protein (CP) (3.18 vs. 3.31%; p = 0.021) resulted higher in Fg. Similarly, starch digestibility increased in animals offered Fg diet versus Ct (0.94 vs. 0.98; p = 0.078). Among the reticular parameters, the Fg-fed cows spent a significantly higher time below the 5.5 pH threshold (15 vs. 61 min/day; p = 0.047) and had an average daily variation in reticular pH characterised by a lower nadir pH (5.95 vs. 5.72; p < 0.001) and a higher pH range (0.79 vs. 0.94; p = 0.003). In this study, grain particle size affected the risk of the onset of ruminal acidosis. Therefore, it should be carefully considered when formulating rations. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

  5. Origins of n-alkanes, carbonyl compounds and molecular biomarkers in atmospheric fine and coarse particles of Athens, Greece.

    Science.gov (United States)

    Andreou, G; Rapsomanikis, S

    2009-10-15

    The abundance and origin of aliphatic hydrocarbons, carbonyl compounds and molecular biomarkers found in the aliphatic fraction of PM(10-2.5) and PM(2.5) in the centre of Athens Greece are discussed in an attempt to reveal seasonal air pollution characteristics of the conurbation. Each extract was fractionated into individual compound classes and was analyzed using gas chromatography coupled to mass spectrometry. Normal alkanes, ranging from C(14) to C(35), were abundant in PM(10-2.5) and PM(2.5) samples during both sampling campaigns. The daily concentration of total n-alkanes was up to 438 ng m(-3) for PM(10-2.5) and up to 511 ng m(-3) for PM(2.5). Additionally, gaseous concentrations of n-alkanes were calculated, revealing that the relative proportions between gaseous and particle phases of individual compounds may differ significantly between summer and late winter. Normal alkanals and alkan-2-ones were only detected in the fine fraction of particulate matter and their concentrations were much lower than the n-alkane concentrations. Several geochemical parameters were used to qualitatively reconcile the sources of organic aerosol. The carbon preference index (CPI) of the coarse particles in August had the highest value, while in March the leaf wax contribution decreased significantly and the CPI value was very close to unity for both sites. Maximum concentrations of carbonyl compounds were reported in the range of C(15)-C(20), demonstrating that they were formed from anthropogenic activity or from atmospheric oxidative processes. 6, 10, 14-trimethylpentadecan-2-one, a marker of biogenic input, was also detected in our samples. Molecular biomarker compounds confirmed that ca. 60% of the aliphatic fraction on the sampled atmospheric particles originated from petroleum and not from any contemporary biogenic sources. Pristane and phytane were detected in the fine fraction with their presence indicating sources of fossil fuel in the range of C(16)-C(20). At all

  6. Free and combined amino compounds in atmospheric fine particles (PM 2.5) and fog waters from Northern California

    Science.gov (United States)

    Zhang, Qi; Anastasio, Cort

    Atmospheric fine particles (PM 2.5) collected during August 1997-July 1998 and wintertime fog waters collected during 1997-1999 at Davis, California were analyzed for free and combined amino compounds. In both PM 2.5 and fog waters, the average concentrations of combined amino compounds (CAC, e.g., proteins and peptides) were generally 4-5 times higher than those of free amino compounds (FAC, i.e., amino acids and alkyl amines). Concentrations of total amino compounds (TAC=FAC+CAC) ranged from 1260 to 3650 pmol m -3 air in PM 2.5, and from 1620 to 5880 pmol m -3 air in fog waters. Average values (±1 σ) were 2500±879 and 3400±1430 pmol m -3 air, respectively. Concentrations of amino compounds in PM 2.5 varied seasonally, with a peak during late winter and early spring. Ornithine was a major FAC component in both PM 2.5 and fog waters (typically accounting for ˜20% of FAC), but these sample types otherwise had fairly different FAC distributions. FAC in PM 2.5 were enriched in protein-type amino species such as glycine/threonine, serine and alanine, while fog water FAC had significantly higher levels of non-protein species such as methylamine, γ-aminobutyric acid and ethanolamine. The compositions of CAC in PM 2.5 and fogs were fairly similar and were mainly protein-type. Mass concentrations of TAC in PM 2.5 and fog waters were, on average, 302 and 399 ng m -3 air, respectively. Amino compounds were an important component of the organic carbon pool for both fog and particles, with TAC accounting for an average of 13% of the dissolved organic carbon in fog waters and ˜10% of the water-soluble organic carbon in PM 2.5. At these levels amino compounds likely play important roles in the chemistry of fog drops and fine particles, for example by influencing their buffering capacity and basicity.

  7. Cardiovascular effects of sub-daily levels of ambient fine particles: a systematic review

    Directory of Open Access Journals (Sweden)

    Perron Stéphane

    2010-06-01

    Full Text Available Abstract Background While the effects of daily fine particulate exposure (PM have been well reviewed, the epidemiological and physiological evidence of cardiovascular effects associated to sub-daily exposures has not. We performed a theoretical model-driven systematic non-meta-analytical literature review to document the association between PM sub-daily exposures (≤6 hours and arrhythmia, ischemia and myocardial infarction (MI as well as the likely mechanisms by which sub-daily PM exposures might induce these acute cardiovascular effects. This review was motivated by the assessment of the risk of exposure to elevated sub-daily levels of PM during fireworks displays. Methods Medline and Elsevier's EMBase were consulted for the years 1996-2008. Search keywords covered potential cardiovascular effects, the pollutant of interest and the short duration of the exposure. Only epidemiological and experimental studies of adult humans (age > 18 yrs published in English were reviewed. Information on design, population and PM exposure characteristics, and presence of an association with selected cardiovascular effects or physiological assessments was extracted from retrieved articles. Results Of 231 articles identified, 49 were reviewed. Of these, 17 addressed the relationship between sub-daily exposures to PM and cardiovascular effects: five assessed ST-segment depression indicating ischemia, eight assessed arrhythmia or fibrillation and five considered MI. Epidemiologic studies suggest that exposure to sub-daily levels of PM is associated with MI and ischemic events in the elderly. Epidemiological studies of sub-daily exposures suggest a plausible biological mechanism involving the autonomic nervous system while experimental studies suggest that vasomotor dysfunction may also relate to the occurrence of MI and ischemic events. Conclusions Future studies should clarify associations between cardiovascular effects of sub-daily PM exposure with PM size

  8. Sources and Chemical Composition of Atmospheric Fine Particles in Rabigh, Saudi Arabia

    Science.gov (United States)

    Nayebare, S. R.; Aburizaiza, O. S.; Siddique, A.; Hussain, M. M.; Zeb, J.; Khwaja, H. A.

    2014-12-01

    Air pollution research in Saudi Arabia and the whole of Middle East is at its inception, making air pollution in the region a significant problem. This study presents the first detailed data on fine particulate matter (PM2.5) concentrations of Black Carbon (BC), ions, and trace metals at Rabigh, Saudi Arabia, and assesses their sources. Results showed several characteristic aspects of air pollution at Rabigh. Daily levels of PM2.5 and BC showed significant temporal variability ranging from 12.2 - 75.9 µg/m3 and 0.39 - 1.31 µg/m3, respectively. More than 90% of the time, the daily PM2.5 exceeded the 24 h WHO guideline of 20 µg/m3. Sulfate, NO3-, and NH4+ dominated the identifiable components. Trace metals with significantly higher concentrations included Si, S, Ca, Al, Fe, Na, Cl, Mg, K, and Ti, with average concentrations of 3.1, 2.2, 1.6, 1.2, 1.1, 0.7, 0.7, 0.5, 0.4 and 0.1 µg/m3, respectively. Based on the Air Quality Index (AQI), there were 44% days of moderate air quality, 33% days of unhealthy air quality for sensitive groups, and 23% days of unhealthy air quality throughout the study period. Two categories of aerosol trace metal sources were defined: anthropogenic (S, V, Cr, Ni, Cu, Zn, Br, Cd, Sb, and Pb) and naturally derived elements (Si, Al, and Fe). The extent of anthropogenic contribution was estimated by the degree of enrichment of these elements compared to the crustal composition. Soil resuspension and/or mobilization is an important source of "natural" elements, while "anthropogenic" elements originate primarily from fossil fuel combustion and industries. Ni and V correlated strongly pointing to combustion of heavy fuel oil as the likely source. A positive matrix factorization (PMF) was used to obtain information about possible sources. Our study highlights the need for stringent laws on PM2.5 emission control to protect human health and the environment.

  9. Fine Particle Pollution, Alanine Transaminase, and Liver Cancer: A Taiwanese Prospective Cohort Study (REVEAL-HBV).

    Science.gov (United States)

    Pan, Wen-Chi; Wu, Chih-Da; Chen, Mu-Jean; Huang, Yen-Tsung; Chen, Chien-Jen; Su, Huey-Jen; Yang, Hwai-I

    2016-03-01

    Exposure to fine particulate matter (PM2.5) may promote hepatic tumorgenesis through low-grade inflammation. Therefore, we assessed the association of long-term exposure levels of PM2.5 and subsequent risk of hepatocellular carcinoma (HCC) and investigated the mediation effect of inflammation as represented by alanine aminotransferase (ALT) on this association. Between 1991 and 1992, we recruited 23 820 participants in Taiwan with no history of HCC. Case patients of HCC were ascertained through computerized data linkage with the National Cancer Registry and death certification systems. Participants' exposures to PM2.5 were based on a four-year average retrieved from stationary monitoring sites. Cox proportional hazards models were used to assess the association between PM2.5 exposure and HCC incidence. Mediation effects of ALT on PM2.5-associated HCC incidence were estimated. A total of 464 HCC cases were newly diagnosed with a median follow-up of 16.9 years. Statistically significantly increasing trends between PM2.5 exposures and ALT were observed on the Main Island and Penghu Islets. The adjusted hazard ratio (HR) for HCC on the Penghu Islets was 1.22 (95% confidence interval [CI] = 1.02 to 1.47) per PM2.5 interquartile range (IQR) increment (0.73 µg/m(3)) exposure. We also found a positive association between PM2.5 exposure (per IQR increment, 13.1 µg/m(3)) and HCC incidence on the Main Island. Furthermore, ALT had a statistically significant mediation effect on PM2.5-associated HCC incidence (HR = 1.17, 95% CI = 1.02 to1.52 on the Main Island; HR = 1.04, 95% CI = 1.03 to 1.07 on the Penghu Islets) per PM2.5 IQR increment. Long-term PM2.5 exposure increased the risk for liver cancer, and chronic inflammation of the liver may underlie the pathogenesis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. [Comparison of Monitoring Methods of Organic Carbon and Element Carbon in Atmospheric Fine Particles].

    Science.gov (United States)

    Pang, Bo; Ji, Dong-sheng; Liu, Zi-rui; Zhu, Bin; Wang, Yue-si

    2016-04-15

    Accurate measurement of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particulate is an important scientific basis for studying the formation and source apportionment of carbonaceous aerosol. The selection of different analysis programs will lead to difference in the OC and EC concentrations, and further result in the misjudgment of the results. The OC and EC concentrations observed using three temperature protocols including RT-Quartz ( R) , NIOSH 5040 (N) and Fast-TC (F) were compared and analyzed in combination with the degree of air pollution in Beijing. The results showed that there was no significant difference in the TC (TC = OC + EC), OC and EC concentrations observed using R, N and F protocols and certain deviation was found among the TC (TC = OC + EC) , OC and EC concentrations. For TC, the results observed using R protocol were 5% lower than those using N protocol; hut 1% higher than those using F protocol. For OC, the results obtained using R were 9% lower than those using N protocol and 1% higher than those using F protocol. For EC, the results obtained using R were 20% higher than those using N protocol and 11% lower than those using F protocol. The variation coefficients for TC, OC and EC obtained based on R protocol were less than the other two temperature protocols under different air quality degrees. The slopes of regression curves of TC, OC and EC between on-line analysis using R protocol and off-line analysis were 1.21,1. 14 and 1.35, respectively. The correlation coefficients of TC, OC and EC were 0.99, 0.99 and 0.98, respectively. In contrast with the Black carbon ( BC) concentrations monitored by multi-angle absorption spectrophotometer (MAAP), the EC concentrations measured by on-line OC/EC analyzer using R protocol were obviously lower. When the BC concentrations were less than or equal to 8 gg*m3, the EC/BC ratio was 0.39. While the EC/BC ratio was 0.88, when the BC concentrations were greater than 8 ggm3. The variation

  11. Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A campaign

    Science.gov (United States)

    Xu, Xuezhe; Zhao, Weixiong; Zhang, Qilei; Wang, Shuo; Fang, Bo; Chen, Weidong; Venables, Dean S.; Wang, Xinfeng; Pu, Wei; Wang, Xin; Gao, Xiaoming; Zhang, Weijun

    2016-05-01

    The optical properties and chemical composition of PM1.0 particles in a suburban environment (Huairou) near the megacity of Beijing were measured during the HOPE-J3A (Haze Observation Project Especially for Jing-Jin-Ji Area) field campaign. The campaign covered the period November 2014 to January 2015 during the winter coal heating season. The average values and standard deviations of the extinction, scattering, absorption coefficients, and the aerosol single scattering albedo (SSA) at λ = 470 nm during the measurement period were 201 ± 240, 164 ± 202, 37 ± 43 Mm-1, and 0.80 ± 0.08, respectively. The average values for the real and imaginary components of the effective complex refractive index (CRI) over the campaign were 1.40 ± 0.06 and 0.03 ± 0.02, while the average mass scattering and absorption efficiencies (MSEs and MAEs) of PM1.0 were 3.6 and 0.7 m2 g-1, respectively. Highly time-resolved air pollution episodes clearly show the dramatic evolution of the PM1.0 size distribution, extensive optical properties (extinction, scattering, and absorption coefficients), and intensive optical properties (SSA and CRI) during haze formation, development, and decline. Time periods were classified into three different pollution levels (clear, slightly polluted, and polluted) for further analysis. It was found that (1) the relative contributions of organic and inorganic species to observed aerosol composition changed significantly from clear to polluted days: the organic mass fraction decreased from 50 to 43 % while the proportion of sulfates, nitrates, and ammonium increased strongly from 34 to 44 %. (2) Chemical apportionment of extinction, calculated using the IMPROVE algorithm, tended to underestimate the extinction compared to measurements. Agreement with measurements was improved by modifying the parameters to account for enhanced absorption by elemental carbon (EC). Organic mass was the largest contributor (52 %) to the total extinction of PM1.0, while EC

  12. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

    Directory of Open Access Journals (Sweden)

    Yi Zhou

    Full Text Available Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm and M. galloprovincialis (shell height: 4.43 ± 0.98 cm was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1 • d(-1, respectively. The total solid suspension (TSS deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P < 0.001. Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P < 0.05. It was suggested that the filter feeders C. gigas and M. galloprovincialis had considerable potential to filter and accelerate the deposition of suspended particles from industrial aquaculture wastewater, and simultaneously yield value-added biological products.

  13. Titanium dioxide (TiO2) fine particle capture and BVOC emissions of Betula pendula and Betula pubescens at different wind speeds

    Science.gov (United States)

    Räsänen, Janne V.; Leskinen, Jari T. T.; Holopainen, Toini; Joutsensaari, Jorma; Pasanen, Pertti; Kivimäenpää, Minna

    2017-03-01

    Trees are known to affect air quality by capturing a remarkable amount of particles from the atmosphere. However, the significance of trees in removing very fine particles (diameter less than 0.5 μm) is not well understood. We determined particle capture efficiency (Cp) of two birch species: Betula pendula and Betula pubescens by using inert titanium dioxide fine particles (TiO2, geometric mean diameter 0.270 μm) at three wind speeds (1, 3 and 6 ms-1) in a wind tunnel. Capture efficiencies were determined by measuring densities of TiO2 particles on leaf surfaces by scanning electron microscopy. In addition, the particle intake into an inner structure of leaves was studied by transmission electron microscopy. The effects of fine particle exposure and wind speed on emission rates of biogenic volatile organic compounds (BVOCs) were measured. Particles were captured (Cp) equally efficiently on foliage of B. pendula (0.0026 ± 0.0005) % and B. pubescens (0.0025 ± 0.0006) %. Increasing wind speed significantly decreased Cp. Increasing wind speed increased deposition velocity (Vg) on B. pendula but not on B. pubescens. Particles were deposited more efficiently on the underside of B. pendula leaves, whereas deposition was similar on the upper and under sides of B. pubescens leaves. TiO2 particles were found inside three of five B. pendula leaves exposed to particles at a wind speed of 1 ms-1 indicating that particles can penetrate into the plant structure. Emission rates of several mono-, homo- and sesquiterpenes were highest at a wind speed of 3 ms-1 in B. pendula. In B. pubescens, emission rates of a few monoterpenes and nonanal decreased linearly with wind speed, but emission rates of sesquiterpenes were lowest at 3 ms-1 and increased at 6 ms-1. Emission rates of a few green leaf volatile compounds increased with increasing wind speed in both species. The results of this study suggest that the surface structure of trees is less important for capturing particles with

  14. Characterization of Fine Airborne Particulate Collected in Tokyo and Major Atmospheric Emission Sources by Using Single Particle Measurement of SEM-EDX

    Science.gov (United States)

    Sato, K.; Iijima, A.; Furuta, N.

    2008-12-01

    In our long-term monitoring of size-classified Airborne Particulate Matter (APM) in Tokyo since 1995, it had been demonstrated that toxic elements such as As, Se, Cd, Sb and Pb were extremely enriched in fine APM (PM2.5). However, in that study, total sampled APM on a filter was digested with acids, and thus only averaged elemental composition in fine APM could be obtained. One of the effective methods to determine the origin of APM is single particle measurement by using SEM-EDX. By using characteristic shapes observed by SEM and marker elements contained in APM measured by EDX, detailed information for source identification can be obtained. In this study, fine APM (PM2.5) was collected at various locations such as roadside, diesel vehicle exhaust, a heavy oil combustion plant and a waste incineration plant as well as ambient atmosphere in Tokyo, and characteristics of fine particles that will be utilized for identification of emission sources are elucidated. Fine particles can be classified into 3 main characteristic shape groups; edge-shaped, cotton-like and spherical. Shape of particles collected in a heavy oil combustion plant and a waste incineration plant was mostly spherical, and these particles may be associated with thermal process. Diesel exhaust particles were predominantly cotton-like which may consist of coagulated nano-sized particles. Most of brake abrasion dusts were edge-shaped, which may be associated with mechanical abrasion of brake pads. In the elemental analysis of fine particles, high concentrations of Sb, Cu, Ti and Ba were detected in brake abrasion dusts. Since these elements are major constituents of brake pads, these can be used for marker elements of brake abrasion dusts. High concentration of C was detected in diesel exhaust particles and oil combustion particles, and thus C can be used for marker elements of their origin. Furthermore, high concentrations of C, Ca and K were detected in fly ash from a waste incineration plant, which

  15. JPRS Report, Science & Technology, Japan, Fine Ceramics Industry Basic Issues Forum

    Science.gov (United States)

    2007-11-02

    substrate material, and phosphates for use as bioceramic materials; and such structural materials as zirconia, silicon 26 carbide, and silicon nitride. R&D...communications equipment, and for bioceramics materials in the medical equipment field. And while R&D has yet to get underway, it is hoped that fine ceramics...Lion Corporation Bioceramic dental crowns Ishihara Pharmaceuticals Aluminum titanate machinable

  16. A Voxel-Based Morphometry Study Reveals Local Brain Structural Alterations associated With Ambient Fine Particles in older women

    Directory of Open Access Journals (Sweden)

    Ramon Casanova

    2016-10-01

    Full Text Available Objective: Exposure to ambient fine particulate matter (PM2.5: PM with aerodynamic diameters <2.5µm has been linked with cognitive deficits in older adults. Using fine-grained voxel-wise analyses, we examined whether PM2.5 exposure also affects brain structure.Methods: Brain MRI data were obtained from 1,365 women (aged 71-89 in the Women’s Health Initiative Memory Study and local brain volumes were estimated using RAVENS (regional analysis of volumes in normalized space. Based on geocoded residential locations and air monitoring data from the U.S. Environmental Protection Agency, we employed a spatiotemporal model to estimate long-term (3-year average exposure to ambient PM2.5 preceding MRI scans. Voxel-wise linear regression models were fit separately to gray matter (GM and white matter (WM maps to analyze associations between brain structure and PM2.5 exposure, with adjustment for potential confounders. Results: Increased PM2.5 exposure was associated with smaller volumes in both cortical GM and subcortical WM areas. For GM, associations were clustered in the bilateral superior, middle, and medial frontal gyri. For WM, the largest clusters were in the frontal lobe, with smaller clusters in the temporal, parietal, and occipital lobes. No statistically significant associations were observed between PM2.5 exposure and hippocampal volumes. Conclusions: Long-term PM2.5 exposures may accelerate loss of both GM and WM in older women. While our previous work linked WM decreased volumes to PM2.5 air pollution, this is the first neuroimaging study reporting associations between air pollution exposure and smaller volumes of cortical GM. Our data support the hypothesized synaptic neurotoxicity of airborne particles.

  17. Response of spontaneously hypertensive rats to inhalation of fine and ultrafine particles from traffic: experimental controlled study

    Directory of Open Access Journals (Sweden)

    Dormans Jan AMA

    2006-05-01

    Full Text Available Abstract Background Many epidemiological studies have shown that mass concentrations of ambient particulate matter (PM are associated with adverse health effects in the human population. Since PM is still a very crude measure, this experimental study has explored the role of two distinct size fractions: ultrafine (3 to 3613 μg/m3 for fCAP and from 269μg/m3 to 556 μg/m3 for u+fCAP. Results Ammonium, nitrate, and sulphate ions accounted for 56 ± 16% of the total fCAP mass concentrations, but only 17 ± 6% of the u+fCAP mass concentrations. Unambiguous particle uptake in alveolar macrophages was only seen after u+fCAP exposures. Neither fCAP nor u+fCAP induced significant changes of cytotoxicity or inflammation in the lung. However, markers of oxidative stress (heme oxygenase-1 and malondialdehyde were affected by both fCAP and u+fCAP exposure, although not always significantly. Additional analysis revealed heme oxygenase-1 (HO-1 levels that followed a nonmonotonic function with an optimum at around 600 μg/m3 for fCAP. As a systemic response, exposure to u+fCAP and fCAP resulted in significant decreases of the white blood cell concentrations. Conclusion Minor pulmonary and systemic effects are observed after both fine and ultrafine + fine PM exposure. These effects do not linearly correlate with the CAP mass. A greater component of traffic CAP and/or a larger proportion ultrafine PM does not strengthen the absolute effects.

  18. Classification mechanism of the chute, a liquid-phase remover of fines in the micrometre range from a batch of porous particles

    NARCIS (Netherlands)

    Jonker, G.H.; Hoffmann, A.C; Beenackers, A.A C M

    1997-01-01

    A simple and effective classification method, the 'chute', has been developed for the liquid-phase removal of fines from a batch of porous (catalyst) particles in the micrometre range. The chute is a continuous sedimentation fractionator, working in the gravitational field. Equations based an the se

  19. Metallic nickel nano- and fine particles induce JB6 cell apoptosis through a caspase-8/AIF mediated cytochrome c-independent pathway

    Directory of Open Access Journals (Sweden)

    Castranova Vincent

    2009-04-01

    Full Text Available Abstract Background Carcinogenicity of nickel compounds has been well documented. However, the carcinogenic effect of metallic nickel is still unclear. The present study investigates metallic nickel nano- and fine particle-induced apoptosis and the signal pathways involved in this process in JB6 cells. The data obtained from this study will be of benefit for elucidating the pathological and carcinogenic potential of metallic nickel particles. Results Using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay, we found that metallic nickel nanoparticles exhibited higher cytotoxicity than fine particles. Both metallic nickel nano- and fine particles induced JB6 cell apoptosis. Metallic nickel nanoparticles produced higher apoptotic induction than fine particles. Western-blot analysis showed an activation of proapoptotic factors including Fas (CD95, Fas-associated protein with death domain (FADD, caspase-8, death receptor 3 (DR3 and BID in apoptotic cells induced by metallic nickel particles. Immunoprecipitation (IP western blot analysis demonstrated the formation of the Fas-related death-inducing signaling complex (DISC in the apoptotic process. Furthermore, lamin A and beta-actin were cleaved. Moreover, we found that apoptosis-inducing factor (AIF was up-regulated and released from mitochondria to cytoplasm. Interestingly, although an up-regulation of cytochrome c was detected in the mitochondria of metallic nickel particle-treated cells, no cytochrome c release from mitochondria to cytoplasm was found. In addition, activation of antiapoptotic factors including phospho-Akt (protein kinase B and Bcl-2 was detected. Further studies demonstrated that metallic nickel particles caused no significant changes in the mitochondrial membrane permeability after 24 h treatment. Conclusion In this study, metallic nickel nanoparticles caused higher cytotoxicity and apoptotic induction than fine particles in JB6 cells. Apoptotic cell death

  20. Public health risks of prolonged fine particle events associated with stagnation and air quality index based on fine particle matter with a diameter <2.5 μm in the Kaoping region of Taiwan

    Science.gov (United States)

    Lai, Li-Wei

    2016-12-01

    The increasing frequency of droughts in tropical and sub-tropical areas since 1970 due to climate change requires a better understanding of the relationship between public health and long-duration fine particle events (FPE; defined as a day with an average PM2.5 ≥ 35.5 μg/m3) associated with rainfall and wind speed. In the Kaoping region of Taiwan, 94.46 % of the daily average PM2.5 in winter exceeds the limit established by 2005 World Health Organization (WHO) guidelines. This study investigated the differences in winter weather characteristics and health effects between non-FPE and FPE days, and the performance of air quality indexes on FPE days. Z-statistics for one-tailed tests, multiplicative decomposition models, logarithmic regression, and product-moment correlations were used for the analysis. The results indicate that mean wind speeds, rainfall hours, and air temperature were significantly decreased on FPE days. Daily mean PM2.5 concentrations were positively correlated to the duration of FPE days. The duration of FPE days was positively related to the length of drought ( r = 0.97, P 15 years experienced the largest average reduction in asthma admissions on lag-days. Compared to the pollutant standard index (PSI) and revised air quality index (RAQI), the PM2.5 index is more representative and sensitive to changes in PM2.5 concentrations.

  1. Endotoxin in fine (PM 2.5) and coarse (PM 2.5-10) particle mass of ambient aerosols. A temporo-spatial analysis

    Science.gov (United States)

    Heinrich, Joachim; Pitz, Mike; Bischof, Wolfgang; Krug, Norbert; Borm, Paul J. A.

    Objectives: We collected fine (PM 2.5) and coarse (PM 2.5-10) particulate matter fractions in two areas ˜80 km apart and measured soluble endotoxin concentrations in both particle fractions. Here we report on temporo-spatial variation of endotoxin content in the collected particles. Methods: Dichotomous Anderson samplers were used to collect 21 weekly samples of PM 2.5 and PM 2.5-10 in both towns from January to June 2002. Each Teflon filter was water extracted and endotoxin was measured by a chromogenic Limulus Amoebocyte Lysate method. Endotoxin concentrations were expressed per mg of fine or mg of coarse mass and per sampled air volume (m 3). Results: For both cities, the mean endotoxin content in PM 2.5 was 1.2 EU mg -1; however the endotoxin content in the coarse fraction was ˜10 times higher compared to the fine mass fractions. Although endotoxin content is highly variable over time, a good correlation was observed between the two town sites for both fine ( r=0.85) and coarse PM ( r=0.88). The fluctuations of weekly endotoxin means were high in both areas suggesting a strong temporal dependence on particle source and composition. The endotoxin content in particles collected during May and June were two to four times higher than concentrations measured during the winter and early spring weeks. Conclusions: Ambient airborne endotoxin concentrations were detected in coarse and fine particle fraction, but 10-fold higher in the coarse PM. The strong seasonality and the week to week fluctuation of endotoxin content in PM indicate different biologic PM properties which might affect results of time series studies on short-term effects as well as in vitro studies and human exposure studies.

  2. Investigating the sources and atmospheric processing of fine particles from Asia and the Northwestern United States measured during INTEX B

    Directory of Open Access Journals (Sweden)

    R. E. Peltier

    2007-11-01

    Full Text Available During the National Aeronautics and Space Administration (NASA Intercontinental Chemical Transport Experiment, Phase B (INTEX-B, in the spring of 2006, airborne measurements were made in the United States Pacific Northwest of the major inorganic ions and the water-soluble organic carbon (WSOC of submicron (PM1.0 aerosol. An atmospheric trajectory (Hysplit and a Lagrangian particle dispersion model (Flexpart quantifying source contributions for carbon monoxide (CO was used to segregate air masses into those of primarily Asian influence (>75% Asian CO or North American influence (>75% North American CO. Of the measured compounds, fine particle mass mostly consisted of water-soluble organic carbon and sulfate, with highest median WSOC and sulfate concentrations in North American air masses. The fraction of WSOC to sulfate was significantly lower than one at altitudes above 3 km, opposite to what has been observed closer to Asia and in the northeastern United States, where organic components were at higher concentrations than sulfate in the free troposphere. The observations could be explained by loss of sulfate and organic aerosol due to precipitation scavenging, with reformation of mainly sulfate during advection from Asia to North America. WSOC sources were investigated by multivariate linear regression analyses of WSOC and volatile organic compounds (VOCs. In Asian air masses, of the WSOC variability that could be explained (49%, most were related to fossil fuel combustion VOCs, compared to North American air masses, where 75% of the WSOC variability was explained through a nearly equal combination of fossil fuel combustion and biogenic VOCs. Distinct WSOC plumes encountered during the experiment were also studied. A plume observed near the California Central Valley at 0.6 km altitude was related to both fossil fuel combustion and biogenic VOCs. Another Central Valley plume observed over Nevada at 3 to 5 km, in a region of cloud

  3. Temperature- and pH-Responsive Benzoboroxole-Based Polymers for Flocculation and Enhanced Dewatering of Fine Particle Suspensions.

    Science.gov (United States)

    Lu, Han; Wang, Yinan; Li, Lin; Kotsuchibashi, Yohei; Narain, Ravin; Zeng, Hongbo

    2015-12-16

    Random copolymers based on N-isopropylacrylamide (NIPAAm) containing 2-aminoethyl methacrylamide hydrochloride (AEMA) and 5-methacrylamido-1,2-benzoboroxole (MAAmBo) were synthesized and subsequently evaluated for their performance in solid-liquid separation at various pH and temperatures. The strong interactions between benzoboroxole residues and kaolin hydroxyl groups were evaluated for the first time in the flocculation of fine particle suspensions. The lower critical solution temperatures (LCSTs) of PAMN decreases because of the hydrophobic nature of the benzoboroxole moieties, resulting in strong hydrophobic interaction at temperatures higher than the LCSTs. Temperature and pH responsive polymer, P(AEMA51-st-MAAmBo76-st-NIPAM381) (denoted as PAMN) shows the ability to induce fastest settling at a low dosage of 25 ppm and under the condition of pH 9 and 50 °C. The accelerated settling rate is considered to be due to the strong adhesion of benzoboroxole residues to the kaolin hydroxyl groups, the electrical double layer force, and the hydrophobic force. During condensation phase, increasing the pH of sediment to pH 11 could attain the most compact structure. Random copolymers containing benzoboroxole groups act as dispersants (due to pH-responsive character) rather than flocculants at pH 11, providing repulsive force that enables particles to rearrange their position and consolidate well. Through a two-step solid-liquid separation including settling phase and consolidation phase, rapid settling and compact sediment are feasible simultaneously.

  4. In vitro and in vivo evaluation of the toxicities induced by metallic nickel nano and fine particles.

    Science.gov (United States)

    Magaye, Ruth; Gu, Yuanliang; Wang, Yafei; Su, Hong; Zhou, Qi; Mao, Guochuan; Shi, Hongbo; Yue, Xia; Zou, Baobo; Xu, Jin; Zhao, Jinshun

    2016-06-01

    Nickel nanoparticles (Ni NPs) have been applied in various fields along with the rapid development of nanotechnology. However, the potential adverse health effects of the Ni NPs are unclear. To investigate the cyto- and genotoxicity and compare the differences between the Ni NPs and the nickel fine particles (Ni FPs), Sprague-Dawley (SD) rats and A549 cells were treated with different doses of Ni NPs or FPs. Intra-tracheal instillation of Ni NPs and FPs caused acute toxicity in the lungs, liver and kidneys of the SD rats. Even though the histology of the lungs showed hyperplastic changes and the protein expression of HO-1 and Nrf2 detected by western blot showed lung burden overload, no significant increase was observed to the expression level of oncoprotein C-myc. The results from cell titer-Glo assay and comet assay indicated that Ni NPs were more potent in causing cell toxicity and genotoxicity in vitro than Ni FPs. In addition, Ni NPs increased the expression of C-myc in vitro, but these increases may not have been due to oxidative stress since no significant dose-dependent changes were seen in HO-1 and Nrf2 expressions. Although Ni NPs have the potential to cause DNA damage in A549 cells in vitro, the molecular mechanisms that led to these changes and their tumorigenic potential is still debatable. In short, Ni NPs were more potent in causing cell toxicity and genotoxicity in vitro than Ni FPs, and intra-tracheal instillation of Ni NPs and FPs caused toxicity in organs of the SD rats, while it showed similar to the effects for both particle types. These results suggested that both Ni NPs and FPs have the potential to be harmful to human health, and Ni NPs may have higher cyto- and genotoxic effects than Ni FPs under the same treatment dose.

  5. The Physical and Chemical Properties of Fine Carbon Particles-Pinewood Resin Blends and Their Possible Utilization

    Directory of Open Access Journals (Sweden)

    Aviwe Melapi

    2015-01-01

    Full Text Available The application of biomass gasification technology is very important in the sense that it helps to relieve the dwindling supply of natural gas from fossil fuels, and the desired product of its gasification process is syngas. This syngas is a mixture of CO and H2; however, by-products such as char, tar, soot, ash, and condensates are also produced. This study, therefore, investigated selected by-products recovered from the gasification process of pinewood chips with specific reference to their potential application in other areas when used as blends. Three samples of the gasification by-products were obtained from a downdraft biomass gasifier system and were characterized in terms of chemical and physical properties. FTIR analysis confirmed similar spectra in all char-resin blends. For fine carbon particles- (soot- resin blends, almost the same functional groups as observed in char-resin blends appeared. In bomb calorimeter measurements, 70% resin/30% char blends gave highest calorific value, followed by 50% resin/50% soot blends with values of 35.23 MJ/kg and 34.75 MJ/kg consecutively. Provided these by-products meet certain criteria, they could be used in other areas such as varnishes, water purification, and wind turbine blades.

  6. Element determination of fine particles in environmental aerosols using PIXE; Determinacion elemental de paticulas finas en aerosoles ambientales usando PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Garcia O, B. [ITT, 50000 Toluca (Mexico); Aldape U, F. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: gaolivab@gmail.com

    2007-07-01

    The Mexico city is classified as one of the more populated cities of the world which presents a decrease in the air quality and that gives place to a severe problematic in atmospheric pollution. To cooperate in the solution of this problem it is necessary to carry out studies that allow a better knowledge of the atmosphere of the city. This study presents the results of a monitoring campaign of fine particle carried out from September 21 to December 12, 2001 in three sites of the Mexico City center area. The samples were collected every third day with a collector type unit of heaped filters (Gent). The analysis of these samples was carried out in the 2 MV accelerator of the National Institute of Nuclear Research (ININ) applying the PIXE technique and with this analysis its were identified in the samples approximately 15 elements in each one of the 3 sites and was calculated the concentration in that its were present. With these results a database was created and by means of it mathematical treatment the Enrichment factor (FE), the time series of each element and the multiple correlation matrix were evaluated. The obtained results showed that the Civil Registration site (Salto del Agua) it was the more polluted coinciding that to a bigger concentration of activities a bigger increase in the pollution is generated. (Author)

  7. Fine particles in homes of predominantly low-income families with children and smokers: Key physical and behavioral determinants to inform indoor-air-quality interventions

    Science.gov (United States)

    Bellettiere, John; Hughes, Suzanne C.; Nguyen, Benjamin; Berardi, Vincent; Liles, Sandy; Obayashi, Saori; Hofstetter, C. Richard; Blumberg, Elaine; Hovell, Melbourne F.

    2017-01-01

    Children are at risk for adverse health outcomes from occupant-controllable indoor airborne contaminants in their homes. Data are needed to design residential interventions for reducing low-income children's pollutant exposure. Using customized air quality monitors, we continuously measured fine particle counts (0.5 to 2.5 microns) over a week in living areas of predominantly low-income households in San Diego, California, with at least one child (under age 14) and at least one cigarette smoker. We performed retrospective interviews on home characteristics, and particle source and ventilation activities occurring during the week of monitoring. We explored the relationship between weekly mean particle counts and interview responses using graphical visualization and multivariable linear regression (base sample n = 262; complete cases n = 193). We found associations of higher weekly mean particle counts with reports of indoor smoking of cigarettes or marijuana, as well as with frying food, using candles or incense, and house cleaning. Lower particle levels were associated with larger homes. We did not observe an association between lower mean particle counts and reports of opening windows, using kitchen exhaust fans, or other ventilation activities. Our findings about sources of fine airborne particles and their mitigation can inform future studies that investigate more effective feedback on residential indoor-air-quality and better strategies for reducing occupant exposures. PMID:28545099

  8. Fine structure of histograms of alpha-activity measurements depends on direction of alpha particles flow and the Earth rotation: experiments with collimators

    CERN Document Server

    Shnoll, S E; Berulis, I I; Udaltsova, N V; Rubinstein, I A; Shnoll, Simon E.; Zenchenko, Konstantin I.; Berulis, Iosas I.; Udaltsova, Natalia V.; Rubinstein, Ilia A.

    2004-01-01

    The fine structure of histograms of measurements of 239Pu alpha-activity varies periodically, and the period of these variations is equal to sidereal day (1436 minutes). The periodicity is not observed in the experiments with collimator that restricts the alpha particles flow to be oriented to the Polar Star. Based on this study and other independent data, such as measurements conducted by the Arctic expedition, and similarity of the histograms in processes observed at different locations at the same local time, the conclusion was made, that the fine structure of statistical distributions of the observed processes depends on the celestial sphere.

  9. Evidence-based creativity: Working between art and science in the field of fine dining.

    Science.gov (United States)

    Borkenhagen, Chad

    2017-08-01

    This article examines how scientific knowledge drives creativity in the small but influential culinary movement of 'modernist cuisine'. Originating in the mid-1990s, modernist cuisine began with a small group of avant-garde chefs using science to produce wildly innovative culinary creations. Since then, many of the movement's innovations, as well as its more general 'science-based' approach to cooking, have gained adoption among a diverse range of culinary professionals. But while science has enabled modernist chefs to produce a wide array of innovations and refinements, the group's embrace of scientific values poses a potential threat to the subjective, intuition-driven logic of culinary creativity. Using data gathered through interviews and participant observation, I describe how modernist chefs navigate the potential challenges of using science in a creative field. I find that advocates of modernist cuisine address these challenges by adopting two separate rhetorical repertoires - one emphasizing science-based cooking's advantages over traditional methods, and another that minimizes the differences between these approaches. Observing the strategic deployment of these repertoires illustrates the challenges to incorporating science into creative fields and reveals a complex and nuanced relationship between objectivity, evidence, and aesthetic judgement.

  10. Monitoring of Pollution of Air Fine Particles (PM2.5) and Study on Their Genetic Toxicity

    Institute of Scientific and Technical Information of China (English)

    DONG-QUN XU; WEN-LI ZHANG

    2004-01-01

    To compare PM2.5 pollation level between the city of coal-fuel pollution (Taiyuan) and the city of pollution mixed with coal fuels and vehicle exhausts (Beijing), to analyze the concentration of B[a]p and Pb in the pollutants, and to study the DNA damage by PM2.5. Methods Air fine particles (PM2.5) were collected in Beijing and Taiyuan by means of the filter membrane method, the concentration of B[a]p and Pb were analyzed by high performance liquid chromatography and atomic absorption spectroscopy respectveily, and the damage of DNA by PM2.5 was detected by single cell gel-electrophoresis (SCGE) using the human lung epithelial cells (A549) as target cells. Results The concentration of PM2.5 in the winter of Beijing was 0.028-0.436 mg/m3, and that in Taiyuan was 0.132-0.681 mg/m3. The concentration of B[a]p was 0.104 and 0.156 μg/mg on PM2.5 of Beijing and Taiyuan, respectively, whereas the concentration of Pb was 1.094 and 1.137 μg/mg on PM2.5 of Beijing and Taiyuan, respectively. Exposure to PM2.5 at the concentrations of 5, 50, and 200 μg/mL for 12 h and 24 h caused DNA damage of the human alveolar epithelium, and the ratios of the tailing and length of the tail were all significantly different from those of the negative control group (P<0.05), and indicated a dose-response relationship. Conclusion PM2.5 has certain genetic toxicity.

  11. Determinants of fine particle (PM{sub 2.5}) personal exposure levels in transport microenvironments, London, UK

    Energy Technology Data Exchange (ETDEWEB)

    Adams, H.S.; Nieuwenhuijsen, M.J.; Colville, R.N. [Imperial Coll. of Science, Technology and Medicine, TH Huxley School of Environment, Earth Sciences and Engineering, London (United Kingdom)

    2001-07-01

    A series of field studies were carried out in London, UK, during 1999-2000 in which over 400 fine particle (PM{sub 2.5}) personal exposure level measurements were taken for journeys in bicycle, bus, car and underground rail transport microenvironments. This was the first comprehensive PM{sub 2.5} personal exposure study of transport users. Both a fixed-route multi-transport mode study and a study of cyclists' commuter journeys were undertaken. Subsequent to these field studies regression modelling of possible influencing factors of these exposure levels was carried out. Meteorological variables, traffic density, mode and route were considered; the relationships of personal exposure levels with fixed site monitor (FSM) concentrations, and of the FSM concentrations with the potential predictor variables, were also investigated. This analysis of the determinants of transport user exposure to PM{sub 2.5} in London, UK, showed that wind speed had a significant influence on personal exposure levels, though explained only up to 20% of the variability of road transport user exposure levels. The occurrence of higher wind speeds was strongly associated with a decrease in personal exposure levels; a 1.5-2.0 fold difference in exposure level concentrations was estimated between the 10th and 90th percentiles of wind speed. Route was a significant factor, whilst mode was not a significant factor in the street microenvironment (between bicycle, bus and car modes); models incorporating route and mode, as well as wind speed, explained approximately 35% of the variability in PM{sub 2.5} exposure levels. Personal exposure levels were reasonably correlated with urban background FSM concentrations, for fixed-route road mode (bicycle, bus and car) exposure level concentrations, r=0.27 (p<0.01) and for commuter cyclists' exposure level concentrations r=0.58 (p<0.01). (Author)

  12. A Voxel-Based Morphometry Study Reveals Local Brain Structural Alterations Associated with Ambient Fine Particles in Older Women

    Science.gov (United States)

    Casanova, Ramon; Wang, Xinhui; Reyes, Jeanette; Akita, Yasuyuki; Serre, Marc L.; Vizuete, William; Chui, Helena C.; Driscoll, Ira; Resnick, Susan M.; Espeland, Mark A.; Chen, Jiu-Chiuan; Wassertheil-Smoller, Sylvia; Goodwin, Mimi; DeNise, Richard; Lipton, Michael; Hannigan, James; Carpini, Anthony; Noble, David; Guzman, Wilton; Kotchen, Jane Morley; Goveas, Joseph; Kerwin, Diana; Ulmer, John; Censky, Steve; Flinton, Troy; Matusewic, Tracy; Prost, Robert; Stefanick, Marcia L.; Swope, Sue; Sawyer-Glover, Anne Marie; Hartley, Susan; Jackson, Rebecca; Hallarn, Rose; Kennedy, Bonnie; Bolognone, Jill; Casimir, Lindsay; Kochis, Amanda; Robbins, John; Zaragoza, Sophia; Carter, Cameron; Ryan, John; Macias, Denise; Sonico, Jerry; Nathan, Lauren; Voigt, Barbara; Villablanca, Pablo; Nyborg, Glen; Godinez, Sergio; Perrymann, Adele; Limacher, Marian; Anderson, Sheila; Toombs, Mary Ellen; Bennett, Jeffrey; Jones, Kevin; Brum, Sandy; Chatfield, Shane; Vantrees, Kevin; Robinson, Jennifer; Wilson, Candy; Koch, Kevin; Hart, Suzette; Carroll, Jennifer; Cherrico, Mary; Ockene, Judith; Churchill, Linda; Fellows, Douglas; Serio, Anthony; Jackson, Sharon; Spavich, Deidre; Margolis, Karen; Bjerk, Cindy; Truwitt, Chip; Peitso, Margaret; Camcrena, Alexa; Grim, Richard; Levin, Julie; Perron, Mary; Brunner, Robert; Golding, Ross; Pansky, Leslie; Arguello, Sandie; Hammons, Jane; Peterson, Nikki; Murphy, Carol; Morgan, Maggie; Castillo, Mauricio; Beckman, Thomas; Huang, Benjamin; Kuller, Lewis; McHugh, Pat; Meltzer, Carolyn; Davis, Denise; Davis, Joyce; Kost, Piera; Lucas, Kim; Potter, Tom; Tarr, Lee; Shumaker, Sally; Espeland, Mark; Coker, Laura; Williamson, Jeff; Felton, Debbie; Gleiser, LeeAnn; Rapp, Steve; Legault, Claudine; Dailey, Maggie; Casanova, Ramon; Robertson, Julia; Hogan, Patricia; Gaussoin, Sarah; Nance, Pam; Summerville, Cheryl; Peral, Ricardo; Tan, Josh; Bryan, Nick; Davatzikos, Christos; Desiderio, Lisa; Buckholtz, Neil; Molchan, Susan; Resnick, Susan; Rossouw, Jacques; Pottern, Linda

    2016-01-01

    Objective: Exposure to ambient fine particulate matter (PM2.5: PM with aerodynamic diameters voxel-wise analyses, we examined whether PM2.5 exposure also affects brain structure. Methods: Brain MRI data were obtained from 1365 women (aged 71–89) in the Women's Health Initiative Memory Study and local brain volumes were estimated using RAVENS (regional analysis of volumes in normalized space). Based on geocoded residential locations and air monitoring data from the U.S. Environmental Protection Agency, we employed a spatiotemporal model to estimate long-term (3-year average) exposure to ambient PM2.5 preceding MRI scans. Voxel-wise linear regression models were fit separately to gray matter (GM) and white matter (WM) maps to analyze associations between brain structure and PM2.5 exposure, with adjustment for potential confounders. Results: Increased PM2.5 exposure was associated with smaller volumes in both cortical GM and subcortical WM areas. For GM, associations were clustered in the bilateral superior, middle, and medial frontal gyri. For WM, the largest clusters were in the frontal lobe, with smaller clusters in the temporal, parietal, and occipital lobes. No statistically significant associations were observed between PM2.5 exposure and hippocampal volumes. Conclusions: Long-term PM2.5 exposures may accelerate loss of both GM and WM in older women. While our previous work linked smaller WM volumes to PM2.5, this is the first neuroimaging study reporting associations between air pollution exposure and smaller volumes of cortical GM. Our data support the hypothesized synaptic neurotoxicity of airborne particles.

  13. Investigating the sources and atmospheric processing of fine particles from Asia and the Northwestern United States measured during INTEX B

    Directory of Open Access Journals (Sweden)

    E. Apel

    2008-03-01

    Full Text Available During the National Aeronautics and Space Administration (NASA Intercontinental Chemical Transport Experiment, Phase B (INTEX-B, in the spring of 2006, airborne measurements were made in the United States Pacific Northwest of the major inorganic ions and the water-soluble organic carbon (WSOC of submicron (PM1.0 aerosol. An atmospheric trajectory (HYSPLIT and a Lagrangian particle dispersion model (Flexpart quantifying source contributions for carbon monoxide (CO were used to segregate air masses into those of primarily Asian influence (>75% Asian CO or North American influence (>75% North American CO. Of the measured compounds, fine particle mass mostly consisted of water-soluble organic carbon and sulfate, with median sulfate and WSOC concentrations in two to four times higher, respectively, in North American air masses versus transported Asian air masses. The fraction of WSOC to sulfate in transported Asian air masses was significantly lower than one at altitudes above 3 km due to depleted organic aerosol, opposite to what has been observed closer to Asia and in the northeastern United States, where organic components were at higher concentrations than sulfate in the free troposphere. The observations could be explained by loss of sulfate and organic aerosol by precipitation scavenging, with reformation of mainly sulfate during advection from Asia to North America. In contrast to free tropospheric measurements, for all air masses below approximately 2 km altitude median WSOC-sulfate ratios were consistently between one and two. WSOC sources were investigated by multivariate linear regression analyses of WSOC and volatile organic compounds (VOCs. In Asian air masses, of the WSOC variability that could be explained (49%, most was related to fossil fuel combustion VOCs, compared to North American air masses, where 75% of the WSOC variability was explained through a nearly equal combination of fossil fuel combustion and biogenic VOCs

  14. On the Power of Fine Arts Pictorial Imagery in Science Education

    Science.gov (United States)

    Galili, Igal

    2013-01-01

    The paper describes and illustrates the potential of using pictorial artistic images in supporting teaching scientific concepts and the nature of science. In the first part, the case of Giotto's fresco of stigmatization of St. Francis is described within the interpretation of relationship between the figures as between an object and its…

  15. Accelerating science and innovation societal benefits of European research in Particle Physics

    CERN Multimedia

    Radford, Tim; Jakobsson, Camilla; Marsollier, Arnaud; Mexner, Vanessa; O'Connor, Terry

    2013-01-01

    The story so far. Collaborative research in particle physics. The lesson for Europe: co-operation pays. Medicine and life sciences. The body of knowledge: particles harnessed for health. Energy and the environment. Think big: save energy and clean up the planet. Communication and new technologies. The powerhouse of invention. Society and skills. Power to the people. The European Strategy for Particle Physics. Update 2013.

  16. A new approach to the combination of IBA techniques and wind back trajectory data to determine source contributions to long range transport of fine particle air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, David D., E-mail: dcz@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Crawford, Jagoda; Stelcer, Eduard; Atanacio, Armand [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2012-02-15

    A new approach to link HYSPLIT back trajectories to the source of fine particle pollution as characterised by standard IBA techniques is discussed. The example of the long range transport of desert dust from inland Australia across the eastern coast is used to show that over a 10-year period extreme soil events originated from major agricultural regions some 30% of the time and that dust from known deserts are not always the problem.

  17. Parameter and model uncertainty in a life-table model for fine particles (PM2.5: a statistical modeling study

    Directory of Open Access Journals (Sweden)

    Jantunen Matti J

    2007-08-01

    Full Text Available Abstract Background The estimation of health impacts involves often uncertain input variables and assumptions which have to be incorporated into the model structure. These uncertainties may have significant effects on the results obtained with model, and, thus, on decision making. Fine particles (PM2.5 are believed to cause major health impacts, and, consequently, uncertainties in their health impact assessment have clear relevance to policy-making. We studied the effects of various uncertain input variables by building a life-table model for fine particles. Methods Life-expectancy of the Helsinki metropolitan area population and the change in life-expectancy due to fine particle exposures were predicted using a life-table model. A number of parameter and model uncertainties were estimated. Sensitivity analysis for input variables was performed by calculating rank-order correlations between input and output variables. The studied model uncertainties were (i plausibility of mortality outcomes and (ii lag, and parameter uncertainties (iii exposure-response coefficients for different mortality outcomes, and (iv exposure estimates for different age groups. The monetary value of the years-of-life-lost and the relative importance of the uncertainties related to monetary valuation were predicted to compare the relative importance of the monetary valuation on the health effect uncertainties. Results The magnitude of the health effects costs depended mostly on discount rate, exposure-response coefficient, and plausibility of the cardiopulmonary mortality. Other mortality outcomes (lung cancer, other non-accidental and infant mortality and lag had only minor impact on the output. The results highlight the importance of the uncertainties associated with cardiopulmonary mortality in the fine particle impact assessment when compared with other uncertainties. Conclusion When estimating life-expectancy, the estimates used for cardiopulmonary exposure

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

    CERN Document Server

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

    2001-01-01

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

  19. Arterial blood pressure responses to short-term exposure to fine and ultrafine particles from indoor sources - A randomized sham-controlled exposure study of healthy volunteers.

    Science.gov (United States)

    Soppa, Vanessa J; Schins, Roel P F; Hennig, Frauke; Nieuwenhuijsen, Mark J; Hellack, Bryan; Quass, Ulrich; Kaminski, Heinz; Sasse, Birgitta; Shinnawi, Samir; Kuhlbusch, Thomas A J; Hoffmann, Barbara

    2017-10-01

    Particulate air pollution is linked to adverse cardiovascular effects. The aim of the study was to investigate the effect of short-term exposure to indoor particles on blood pressure (BP). We analyzed the association of particle emissions from indoor sources (candle burning, toasting bread, frying sausages) with BP changes in 54 healthy volunteers in a randomized cross-over controlled exposure study. Particle mass concentration (PMC), size-specific particle number concentration (PNC) and lung-deposited particle surface area concentration (PSC) were measured during the 2h exposure. Systolic and diastolic blood pressure were measured before, during, directly, 2, 4 and 24h after exposure. We performed multiple mixed linear regression analyses of different particle metrics and BP. BP significantly increased with increasing PMC, PSC and PNC resulting from toasting bread. For example, an increase per 10µg/m(3) PM10 and PM2.5, systolic BP increased at all time points with largest changes 1h after exposure initiation of 1.5mmHg (95%-CI: 1.1; 1.9) and of 2.2mmHg (95%-CI: 1.3; 3.1), respectively. Our study suggests an association of short-term exposure to fine and ultrafine particles emitted from toasting bread with increases in BP. Particles emitted from frying sausages and candle burning did not consistently affect BP. Copyright © 2017. Published by Elsevier Inc.

  20. B-vitamin Supplementation Mitigates Effects of Fine Particles on Cardiac Autonomic Dysfunction and Inflammation: A Pilot Human Intervention Trial

    Science.gov (United States)

    Zhong, Jia; Trevisi, Letizia; Urch, Bruce; Lin, Xinyi; Speck, Mary; Coull, Brent A.; Liss, Gary; Thompson, Aaron; Wu, Shaowei; Wilson, Ander; Koutrakis, Petros; Silverman, Frances; Gold, Diane R.; Baccarelli, Andrea A.

    2017-04-01

    Ambient fine particle (PM2.5) pollution triggers acute cardiovascular events. Individual-level preventions are proposed to complement regulation in reducing the global burden of PM2.5-induced cardiovascular diseases. We determine whether B vitamin supplementation mitigates PM2.5 effects on cardiac autonomic dysfunction and inflammation in a single-blind placebo-controlled crossover pilot trial. Ten healthy adults received two-hour controlled-exposure-experiment to sham under placebo, PM2.5 (250 μg/m3) under placebo, and PM2.5 (250 μg/m3) under B-vitamin supplementation (2.5 mg/d folic acid, 50 mg/d vitamin B6, and 1 mg/d vitamin B12), respectively. At pre-, post-, 24 h-post-exposure, we measured resting heart rate (HR) and heart rate variability (HRV) with electrocardiogram, and white blood cell (WBC) counts with hematology analyzer. Compared to sham, PM2.5 exposure increased HR (3.8 bpm, 95% CI: 0.3, 7.4; P = 0.04), total WBC count (11.5%, 95% CI: 0.3%, 24.0%; P = 0.04), lymphocyte count (12.9%, 95% CI: 4.4%, 22.1%; P = 0.005), and reduced low-frequency power (57.5%, 95% CI: 2.5%, 81.5%; P = 0.04). B-vitamin supplementation attenuated PM2.5 effect on HR by 150% (P = 0.003), low-frequency power by 90% (P = 0.01), total WBC count by 139% (P = 0.006), and lymphocyte count by 106% (P = 0.02). In healthy adults, two-hour PM2.5 exposure substantially increases HR, reduces HRV, and increases WBC. These effects are reduced by B vitamin supplementation.

  1. Particle Accelerator Applications: Ion and Electron Irradiation in Materials Science, Biology and Medicine

    Science.gov (United States)

    Rodríguez-Fernández, Luis

    2010-09-01

    Although the developments of particle accelerators are devoted to basic study of matter constituents, since the beginning these machines have been applied with different purposes in many areas also. Today particle accelerators are essential instruments for science and technology. This work presents an overview of the main application for direct particle irradiation with accelerator in material science, biology and medicine. They are used for material synthesis by ion implantation and charged particle irradiation; to make coatings and micromachining; to characterize broad kind of samples by ion beam analysis techniques; as mass spectrometers for atomic isotopes determination. In biomedicine the accelerators are applied for the study of effects by charged particles on cells. In medicine the radiotherapy by electron irradiation is widely used, while hadrontherapy is still under development. Also, they are necessary for short life radioisotopes production required in radiodiagnostic.

  2. Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

    Science.gov (United States)

    Vara-Vela, A.; Andrade, M. F.; Kumar, P.; Ynoue, R. Y.; Muñoz, A. G.

    2016-01-01

    The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤ 2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August-6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40-50 % of the total PM10 (i.e. those ≤ 10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the

  3. Mineral-vegetal co-milling: An effective process to improve lignocellulosic biomass fine milling and to increase interweaving between mixed particles.

    Science.gov (United States)

    Motte, J-C; Delenne, J-Y; Rouau, X; Mayer-Laigle, C

    2015-09-01

    Fine-milling is a crucial objective for lignocellulosic biomass valorization. Co-milling appears to be a promising technique to improve its efficiency. However, the mechanisms occurring while co-milling remain poorly understood. In this study, an experimental work was performed to produce co-milled powders from both lignocellulosic (wheat, straw or pine sawdust) and mineral materials (limestone, quartzite or tile) with very contrasted physicochemical properties. The main consequences of co-milling were studied for both materials. A two-component mixing law for the prediction of the blend properties was proposed (particle sizes and true densities) to highlight the gain of this single processing step compared to separate milling and mixing. The predicted values were compared with experimental data for co-milled powders at 7 biomass contents from 0% to 100%. In all cases, co-milling leads to a reduction in particle size of lignocellulosic materials and create strong interweaving with mineral particles.

  4. Proceedings of the 45. annual conference of metallurgists of CIM : interfacial phenomena in fine particle technology : the 6. UBC-McGill-UA international symposium on fundamentals of mineral processing in honor of Professor Janusz S. Laskowski

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Liu, Q. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering] (eds.)

    2006-07-01

    This conference, organized by the Mineral Sciences and Engineering Section of the Metallurgical Society of CIM acknowledged that strong economic growth is the driving force behind record high productivity in the mining industry. The industry must strive to meet the higher demand for raw materials while facing the challenge of stringent environmental constraints. The continuing success of the mining industry will depend on efficient and environmentally sound mineral processing, particularly since the industry has been forced to exploit more complex forms of minerals given the gradual depletion of high-grade mineral resources. In addition to shortages in qualified personnel in mineral processing, the industry is currently facing a general reduction in basic research and training programs, resulting in deficiencies in technologies needed to process complex ores. World experts in mineral processing participated at this conference to share their novel research in fine particle processing, applications of atomic force microscopy, flotation research, particle interactions in mineral processing, flotation froths, grinding, rheology and sulphide flotation chemistry. The sessions of the conference were entitled: atomic force microscopy in flotation research particulate interactions; flotation froths, flocculation and dewatering; grinding and rheology surfactants; flotation froths, particle-bubble interactions; sulphide flotation; and, general flotation froths. The conference featured 37 presentations, of which 6 have been catalogued separately for inclusion in this database. refs., tabs., figs.

  5. Inter-comparison of Seasonal Variation, Chemical Characteristics, and Source Identification of Atmospheric Fine Particles on Both Sides of the Taiwan Strait

    Science.gov (United States)

    Li, Tsung-Chang; Yuan, Chung-Shin; Huang, Hu-Ching; Lee, Chon-Lin; Wu, Shui-Ping; Tong, Chuan

    2016-01-01

    The spatiotemporal distribution and chemical composition of atmospheric fine particles in areas around the Taiwan Strait were firstly investigated. Fine particles (PM2.5) were simultaneously collected at two sites on the west-side, one site at an offshore island, and three sites on the east-side of the Taiwan Strait in 2013–2014. Field sampling results indicated that the average PM2.5 concentrations at the west-side sampling sites were generally higher than those at the east-side sampling sites. In terms of chemical composition, the most abundant water-soluble ionic species of PM2.5 were SO42−, NO3−, and NH4+, while natural crustal elements dominated the metallic content of PM2.5, and the most abundant anthropogenic metals of PM2.5 were Pb, Ni and Zn. Moreover, high OC/EC ratios of PM2.5 were commonly observed at the west-side sampling sites, which are located at the downwind of major stationary sources. Results from CMB receptor modeling showed that the major sources of PM2.5 were anthropogenic sources and secondary aerosols at the both sides, and natural sources dominated PM2.5 at the offshore site. A consistent decrease of secondary sulfate and nitrate contribution to PM2.5 suggested the transportation of aged particles from the west-side to the east-side of the Taiwan Strait. PMID:26973085

  6. A parallelized particle tracing code for CFD simulations in Earth Sciences

    OpenAIRE

    Vlad Constantin Manea; Marina Manea; Mihai Pomeran; Lucian Besutiu; Luminita Zlagnean

    2012-01-01

    The problem of convective flows in a highly viscous fluid represents a common research direction in Earth Sciences. In order to trace the convective motion of the fluid material, a source of passive particles (or tracers) that flow at a local convection velocity and do not affect the pattern of flow is commonly used. It is presented a parallelized tracer code that uses passive and weightless particles with their position computed from their displacement during a small time interval at the vel...

  7. Integrated Science Investigation of the Sun (ISIS): Design of the Energetic Particle Investigation

    Science.gov (United States)

    McComas, D. J.; Alexander, N.; Angold, N.; Bale, S.; Beebe, C.; Birdwell, B.; Boyle, M.; Burgum, J. M.; Burnham, J. A.; Christian, E. R.; Cook, W. R.; Cooper, S. A.; Cummings, A. C.; Davis, A. J.; Desai, M. I.; Dickinson, J.; Dirks, G.; Do, D. H.; Fox, N.; Giacalone, J.; Gold, R. E.; Gurnee, R. S.; Hayes, J. R.; Hill, M. E.; Kasper, J. C.; Kecman, B.; Klemic, J.; Krimigis, S. M.; Labrador, A. W.; Layman, R. S.; Leske, R. A.; Livi, S.; Matthaeus, W. H.; McNutt, R. L.; Mewaldt, R. A.; Mitchell, D. G.; Nelson, K. S.; Parker, C.; Rankin, J. S.; Roelof, E. C.; Schwadron, N. A.; Seifert, H.; Shuman, S.; Stokes, M. R.; Stone, E. C.; Vandegriff, J. D.; Velli, M.; von Rosenvinge, T. T.; Weidner, S. E.; Wiedenbeck, M. E.; Wilson, P.

    2016-12-01

    The Integrated Science Investigation of the Sun (ISIS) is a complete science investigation on the Solar Probe Plus (SPP) mission, which flies to within nine solar radii of the Sun's surface. ISIS comprises a two-instrument suite to measure energetic particles over a very broad energy range, as well as coordinated management, science operations, data processing, and scientific analysis. Together, ISIS observations allow us to explore the mechanisms of energetic particles dynamics, including their: (1) Origins—defining the seed populations and physical conditions necessary for energetic particle acceleration; (2) Acceleration—determining the roles of shocks, reconnection, waves, and turbulence in accelerating energetic particles; and (3) Transport—revealing how energetic particles propagate from the corona out into the heliosphere. The two ISIS Energetic Particle Instruments measure lower (EPI-Lo) and higher (EPI-Hi) energy particles. EPI-Lo measures ions and ion composition from ˜20 keV/nucleon-15 MeV total energy and electrons from ˜25-1000 keV. EPI-Hi measures ions from ˜1-200 MeV/nucleon and electrons from ˜0.5-6 MeV. EPI-Lo comprises 80 tiny apertures with fields-of-view (FOVs) that sample over nearly a complete hemisphere, while EPI-Hi combines three telescopes that together provide five large-FOV apertures. ISIS observes continuously inside of 0.25 AU with a high data collection rate and burst data (EPI-Lo) coordinated with the rest of the SPP payload; outside of 0.25 AU, ISIS runs in low-rate science mode whenever feasible to capture as complete a record as possible of the solar energetic particle environment and provide calibration and continuity for measurements closer in to the Sun. The ISIS Science Operations Center plans and executes commanding, receives and analyzes all ISIS data, and coordinates science observations and analyses with the rest of the SPP science investigations. Together, ISIS' unique observations on SPP will enable the

  8. God particles in the perspective of The AlQuran Surah Yunus: 61 and modern science

    Science.gov (United States)

    Jumini, Sri

    2017-01-01

    The Qur'an is the book of Allah revealed to guide human beings, settting the rules of life to enable them to achieve happiness in this world and hereafter. The Qur'an has mentioned various scientific nature detailly and accurately so we are able to find new knowledge which is previously unknown by human being. One was about the God particle (Higgs Boson). This article aims to provide a deeper understanding of the concept of the Higgs Boson, the Higgs Boson explained this concept in detail relatated to 1) Perspective of science 2) Perspective of Al-Qur'an 3) Development of technology or science and technology. This study is a qualitative research using library research (library research) that examines and analyzes the books relating directly or indirectly. The results of the analysis states that 1) The concept of the Higgs Boson particle in terms of basic science is also the reason why almost all elementary particles have a greater mass, 2) The concept of the Higgs Boson in the Qur'an is implied from the results of the comparison interpretation of the commentators in Surah Yunus paragraph 61 related to Atom concepts and smaller particles theory of (Higgs Boson), interpretation of Al-Maraghi, and Al-Misbah. 3) The concept of the Higgs Boson in science and technology provide the most advance technology and it is the greatest achievement in the world of science and technology.

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

    OpenAIRE

    Garcìa Lòpez, Natxo

    2017-01-01

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

  10. Evaluation of the degree of mixing of combinations of dry syrup, powder, and fine granule products in consideration of particle size distribution using near infrared spectrometry.

    Science.gov (United States)

    Yamamoto, Yoshihisa; Suzuki, Toyofumi; Matsumoto, Mika; Ohtani, Michiteru; Hayano, Shuichi; Fukami, Toshiro; Tomono, Kazuo

    2012-01-01

    We used near infrared (NIR) spectroscopy to evaluate the degree of mixing of blended dry syrup (DS) products whose particle sizes are not specified in the Revised 16th Edition of the Japanese Pharmacopoeia, and also evaluated the degree of mixing when powder products or fine granule products were added to DS products. The data obtained were used to investigate the relationship between the particle size distributions of the products studied and the degree of mixing. We found that the particle size distribution characteristics of the 15 DS products studied can be broadly classified into 5 types. Combinations of frequently prescribed products were selected to represent 4 of the 5 particle size distribution types and were blended with a mortar and pestle. The coefficient of variation (CV) decreased as the percent mass of Asverin® Dry Syrup 2% (Asverin-DS) increased in blends of Periactin® Powder 1% (Periactin) and Asverin-DS, indicating an improved degree of mixing (uniformity). In contrast, in blends of Periactin and Mucodyne® DS 33.3%, mixing a combination at a 1:1 mass ratio 40 times resulted in a CV of 20%. Other mixing frequencies and mass ratios resulted in a CV by 50% to 70%, indicating a very poor degree of mixing (poor uniformity). These results suggest that when combining different DSs, or a DS with a powder or fine granule product, the blending obtained with a mortar and pestle improves as the particle size distributions of the components approach each other and as the ranges of the distributions narrow.

  11. An extended particle swarm optimization algorithm based on coarse-grained and fine-grained criteria and its application

    Institute of Scientific and Technical Information of China (English)

    LI Xing-mei; ZHANG Li-hui; QI Jian-xun; ZHANG Su-fang

    2008-01-01

    In order to study the problem that particle swarm optimization (PSO) algorithm can easily trap into local mechanism when analyzing the high dimensional complex optimization problems, the optimization calculation using the information in the iterative process of more particles was analyzed and the optimal system of particle swarm algorithm was improved. The extended particle swarm optimization algorithm (EPSO) was proposed. The coarse-grained and free-grained criteria that can control the selection were given to ensure the convergence of the algorithm. The two criteria considered the parameter selection mechanism under the situation of random probability. By adopting MATLAB7.1, the extended particle swarm optimization algorithm was demonstrated in the resource leveling of power project scheduling. EPSO was compared with genetic algorithm (GA) and common PSO, the result indicates that the variance of the objective function of resource leveling is decreased by 7.9%, 18.2%, respectively, certifying thee effectiveness and stronger global convergence ability of the EPSO.

  12. Behavior of HVOF WC-10Co4Cr Coatings with Different Carbide Size in Fine and Coarse Particle Abrasion

    Science.gov (United States)

    Ghabchi, Arash; Varis, Tommi; Turunen, Erja; Suhonen, Tomi; Liu, Xuwen; Hannula, S.-P.

    2010-01-01

    A modified ASTM G 65 rubber wheel test was employed in wet and dry conditions using 220 nm titania particles and 368 μm sand particles, respectively. Both tests were conducted on WC-CoCr coatings produced with two powders with different carbide grain sizes (conventional and sub-micron) to address the effect of carbide size and abrasive medium characteristics on the wear performance. The same spot before and after the wet abrasion wear testing was analyzed in detail using SEM to visualize wear mechanisms. It was shown that the wear mechanism depends on the relative size of the carbide and abrasive particles. Wear mechanisms in dry sand abrasion were studied by analyzing the single scratches formed by individual abrasive particles. Interaction of surface open porosity with moving abrasive particles causes formation of single scratches. By tailoring the carbide size, the wear performance can be improved.

  13. The formation of ultra-fine particles during ozone-initiated oxidations with terpenes emitted from natural paint

    Energy Technology Data Exchange (ETDEWEB)

    Lamorena, Rheo B. [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-Dong, Yuseong-Gu, Daejeon 305-701 (Korea, Republic of); Jung, Sang-Guen [Environment and Process Technology Division, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Bae, Gwi-Nam [Environment and Process Technology Division, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Lee, Woojin [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-Dong, Yuseong-Gu, Daejeon 305-701 (Korea, Republic of)]. E-mail: woojin_lee@kaist.ac.kr

    2007-03-06

    The formation of secondary products during the ozone-initiated oxidations with biogenic VOCs emitted from natural paint was investigated in this study. Mass spectrometry and infrared spectroscopy measurements have shown that the major components of gas-phase chemicals emitted from natural paint are monoterpenes including {alpha}- and {beta}-pinenes, camphene, p-cymene, and limonene. A significant formation of gaseous carbonyl products and nano-sized particles (4.4-168 nm) was observed in the presence of ozone. Carboxylic acids were also observed to form during the reactions (i.e. formic acid at 0.170 ppm and acetic acid at 0.260 ppm). The formation of particles increased as the volume of paint introduced into a reaction chamber increased. A secondary increase in the particle number concentration was observed after 440 min, which suggests further partitioning of oxidation products (i.e. carboxylic acids) into the particles previously existing in the reaction chamber. The growth of particles increased as the mean particle diameter and particle mass concentrations increased during the reaction. The experimental results obtained in this study may provide insight into the potential exposure of occupants to irritating chemical compounds formed during the oxidations of biogenic VOCs emitted from natural paint in indoor environments.

  14. Influence of Particle Theory Conceptions on Pre-Service Science Teachers' Understanding of Osmosis and Diffusion

    Science.gov (United States)

    AlHarbi, Nawaf N. S.; Treagust, David F.; Chandrasegaran, A. L.; Won, Mihye

    2015-01-01

    This study investigated the understanding of diffusion, osmosis and particle theory of matter concepts among 192 pre-service science teachers in Saudi Arabia using a 17-item two-tier multiple-choice diagnostic test. The data analysis showed that the pre-service teachers' understanding of osmosis and diffusion concepts was mildly correlated with…

  15. Particle Physics as a way to bring different cultures to work together in Science

    CERN Document Server

    Mikenberg, G

    2016-01-01

    Science has traditionally played an important role in sharing knowledge among people. Particle Physics, with its large experiments, has shown that one not only can share the knowledge among different cultures, but that one can also work together to achieve this knowledge. The present article gives a few examples where this has been possible among people that are sometimes in conflict situations.

  16. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy for mapping nano-scale distribution of organic carbon forms in soil: Application to black carbon particles

    Science.gov (United States)

    Lehmann, Johannes; Liang, Biqing; Solomon, Dawit; Lerotic, Mirna; LuizãO, Flavio; Kinyangi, James; SchäFer, Thorsten; Wirick, Sue; Jacobsen, Chris

    2005-03-01

    Small-scale heterogeneity of organic carbon (C) forms in soils is poorly quantified since appropriate analytical techniques were not available up to now. Specifically, tools for the identification of functional groups on the surface of micrometer-sized black C particles were not available up to now. Scanning Transmission X-ray Microscopy (STXM) using synchrotron radiation was used in conjunction with Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy to investigate nano-scale distribution (50-nm resolution) of C forms in black C particles and compared to synchrotron-based FTIR spectroscopy. A new embedding technique was developed that did not build on a C-based embedding medium and did not pose the risk of heat damage to the sample. Elemental sulfur (S) was melted to 220°C until it polymerized and quenched with liquid N2 to obtain a very viscous plastic S in which the black C could be embedded until it hardened to a noncrystalline state and was ultrasectioned. Principal component and cluster analysis followed by singular value decomposition was able to resolve distinct areas in a black carbon particle. The core of the studied biomass-derived black C particles was highly aromatic even after thousands of years of exposure in soil and resembled the spectral characteristics of fresh charcoal. Surrounding this core and on the surface of the black C particle, however, much larger proportions of carboxylic and phenolic C forms were identified that were spatially and structurally distinct from the core of the particle. Cluster analysis provided evidence for both oxidation of the black C particle itself as well as adsorption of non-black C. NEXAFS spectroscopy has great potential to allow new insight into black C properties with important implications for biogeochemical cycles such as mineralization of black C in soils and sediments, and adsorption of C, nutrients, and pollutants as well as transport in the geosphere, hydrosphere, and atmosphere.

  17. Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 year study

    Science.gov (United States)

    Cusack, M.; Pérez, N.; Pey, J.; Alastuey, A.; Querol, X.

    2013-05-01

    The chemical composition and sources of ambient fine particulate matter (PM1) over a period of 2.5 years for a regional background site in the western Mediterranean are presented in this work. Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. The mean PM1 concentration for the measurement period was 8.9 μg m-3, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μg m-3 respectively). Six sources were identified in PM1 by Positive Matrix Factorisation (PMF): secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. Typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source were recorded in January, April and October, which were attributed to the occurrence of the aforementioned pollution episodes and local biomass burning emission sources, which include agriculture and domestic heating systems. Average particle number concentrations (N9-825 nm) from 5/11/2010 to 01/06/2011 and from 15/10/2011 to 18/12/2011 reached 3097 cm-3. Five emission sources of particle of sub-micron particles were determined by Principal Component Analysis (PCA); industrial + traffic + biomass

  18. Oxide Particle Growth During Friction Stir Welding of Fine Grain MA956 Oxide Dispersion-Strengthened Steel

    Science.gov (United States)

    Baker, Brad W.; Knipling, Keith E.; Brewer, Luke N.

    2017-03-01

    Friction stir welding of an aluminum-containing oxide dispersion-strengthened steel causes significant oxide particle growth visible at both the nano- and microscales. Quantitative stereology of scanning electron images, small-angle X-ray scattering, energy-dispersive X-ray spectroscopy, and atom-probe tomography is used to quantify the degree of particle coarsening as a function of welding parameters. Results show the dispersed oxides are significantly coarsened in the stir zone due to a proposed combination of agglomeration, Ostwald ripening, and phase transformation within the Al2O3-Y2O3 system. This oxide particle coarsening effectively removes all strengthening contribution of the original oxide particles, as confirmed by uniaxial tensile tests and microhardness measurements.

  19. Oxide Particle Growth During Friction Stir Welding of Fine Grain MA956 Oxide Dispersion-Strengthened Steel

    Science.gov (United States)

    Baker, Brad W.; Knipling, Keith E.; Brewer, Luke N.

    2017-01-01

    Friction stir welding of an aluminum-containing oxide dispersion-strengthened steel causes significant oxide particle growth visible at both the nano- and microscales. Quantitative stereology of scanning electron images, small-angle X-ray scattering, energy-dispersive X-ray spectroscopy, and atom-probe tomography is used to quantify the degree of particle coarsening as a function of welding parameters. Results show the dispersed oxides are significantly coarsened in the stir zone due to a proposed combination of agglomeration, Ostwald ripening, and phase transformation within the Al2O3-Y2O3 system. This oxide particle coarsening effectively removes all strengthening contribution of the original oxide particles, as confirmed by uniaxial tensile tests and microhardness measurements.

  20. Photocatalytic H2 Evolution Using Different Commercial TiO2 Catalysts Deposited with Finely Size-Tailored Au Nanoparticles: Critical Dependence on Au Particle Size

    Directory of Open Access Journals (Sweden)

    Ákos Kmetykó

    2014-11-01

    Full Text Available One weight percent of differently sized Au nanoparticles were deposited on two commercially available TiO2 photocatalysts: Aeroxide P25 and Kronos Vlp7000. The primary objective was to investigate the influence of the noble metal particle size and the deposition method on the photocatalytic activity. The developed synthesis method involves a simple approach for the preparation of finely-tuned Au particles through variation of the concentration of the stabilizing agent. Au was deposited on the TiO2 surface by photo- or chemical reduction, using trisodium citrate as a size-tailoring agent. The Au-TiO2 composites were synthetized by in situ reduction or by mixing the titania suspension with a previously prepared gold sol. The H2 production activities of the samples were studied in aqueous TiO2 suspensions irradiated with near-UV light in the absence of dissolved O2, with oxalic acid or methanol as the sacrificial agent. The H2 evolution rates proved to be strongly dependent on Au particle size: the highest H2 production rate was achieved when the Au particles measured ~6 nm.

  1. Photocatalytic H2 Evolution Using Different Commercial TiO2 Catalysts Deposited with Finely Size-Tailored Au Nanoparticles: Critical Dependence on Au Particle Size

    Science.gov (United States)

    Kmetykó, Ákos; Mogyorósi, Károly; Pusztai, Péter; Radu, Teodora; Kónya, Zoltán; Dombi, András; Hernádi, Klára

    2014-01-01

    One weight percent of differently sized Au nanoparticles were deposited on two commercially available TiO2 photocatalysts: Aeroxide P25 and Kronos Vlp7000. The primary objective was to investigate the influence of the noble metal particle size and the deposition method on the photocatalytic activity. The developed synthesis method involves a simple approach for the preparation of finely-tuned Au particles through variation of the concentration of the stabilizing agent. Au was deposited on the TiO2 surface by photo- or chemical reduction, using trisodium citrate as a size-tailoring agent. The Au-TiO2 composites were synthetized by in situ reduction or by mixing the titania suspension with a previously prepared gold sol. The H2 production activities of the samples were studied in aqueous TiO2 suspensions irradiated with near-UV light in the absence of dissolved O2, with oxalic acid or methanol as the sacrificial agent. The H2 evolution rates proved to be strongly dependent on Au particle size: the highest H2 production rate was achieved when the Au particles measured ~6 nm. PMID:28788264

  2. Photocatalytic H₂ Evolution Using Different Commercial TiO₂ Catalysts Deposited with Finely Size-Tailored Au Nanoparticles: Critical Dependence on Au Particle Size.

    Science.gov (United States)

    Kmetykó, Ákos; Mogyorósi, Károly; Pusztai, Péter; Radu, Teodora; Kónya, Zoltán; Dombi, András; Hernádi, Klára

    2014-11-26

    One weight percent of differently sized Au nanoparticles were deposited on two commercially available TiO₂ photocatalysts: Aeroxide P25 and Kronos Vlp7000. The primary objective was to investigate the influence of the noble metal particle size and the deposition method on the photocatalytic activity. The developed synthesis method involves a simple approach for the preparation of finely-tuned Au particles through variation of the concentration of the stabilizing agent. Au was deposited on the TiO₂ surface by photo- or chemical reduction, using trisodium citrate as a size-tailoring agent. The Au-TiO₂ composites were synthetized by in situ reduction or by mixing the titania suspension with a previously prepared gold sol. The H₂ production activities of the samples were studied in aqueous TiO₂ suspensions irradiated with near-UV light in the absence of dissolved O₂, with oxalic acid or methanol as the sacrificial agent. The H₂ evolution rates proved to be strongly dependent on Au particle size: the highest H₂ production rate was achieved when the Au particles measured ~6 nm.

  3. An Evaluation of the Particle Physics Masterclass as a Context for Student Learning about the Nature of Science

    Science.gov (United States)

    Wadness, Michael J.

    2010-01-01

    This dissertation addresses the research question: To what extent do secondary school science students attending the U.S. Particle Physics Masterclass change their view of the nature of science (NOS)? The U.S. Particle Physics Masterclass is a physics outreach program run by QuarkNet, a national organization of secondary school physics teachers…

  4. Risk assessment strategies for nanoscale and fine-sized titanium dioxide particles: Recognizing hazard and exposure issues.

    Science.gov (United States)

    Warheit, David B; Donner, E Maria

    2015-11-01

    The basic tenets for assessing health risks posed by nanoparticles (NP) requires documentation of hazards and the corresponding exposures that may occur. Accordingly, this review describes the range and types of potential human exposures that may result from interactions with titanium dioxide (TiO2) particles or NP - either in the occupational/workplace environment, or in consumer products, including food materials and cosmetics. Each of those applications has a predominant route of exposure. Very little is known about the human impact potential from environmental exposures to NP - thus this particular issue will not be discussed further. In the workplace or occupational setting inhalation exposure predominates. Experimental toxicity studies demonstrate low hazards in particle-exposed rats. Only at chronic overload exposures do rats develop forms of lung pathology. These findings are not supported by multiple epidemiology studies in heavily-exposed TiO2 workers which demonstrate a lack of correlation between chronic particle exposures and adverse health outcomes including lung cancer and noncancerous chronic respiratory effects. Cosmetics and sunscreens represent the major application of dermal exposures to TiO2 particles. Experimental dermal studies indicate a lack of penetration of particles beyond the epidermis with no consequent health risks. Oral exposures to ingested TiO2 particles in food occur via passage through the gastrointestinal tract (GIT), with studies indicating negligible uptake of particles into the bloodstream of humans or rats with subsequent excretion through the feces. In addition, standardized guideline-mandated subchronic oral toxicity studies in rats demonstrate very low toxicity effects with NOAELs of >1000 mg/kg bw/day. Additional issues which are summarized in detail in this review are: 1) Methodologies for implementing the Nano Risk Framework - a process for ensuring the responsible development of products containing nanoscale

  5. Size-resolved measurements of brown carbon and estimates of their contribution to ambient fine particle light absorption based on water and methanol extracts

    Science.gov (United States)

    Liu, J.; Bergin, M.; Guo, H.; King, L.; Kotra, N.; Edgerton, E.; Weber, R. J.

    2013-07-01

    Light absorbing organic carbon, often termed brown carbon, has the potential to significantly contribute to the visible light absorption budget, particularly at shorter wavelengths. Currently, the relative contributions of particulate brown carbon to light absorption, as well as the sources of brown carbon are poorly understood. With this in mind field measurements were made at both urban (Atlanta), and rural (Yorkville) sites in Georgia. Measurements in Atlanta were made at both a central site and a road side site adjacent to a main highway near the city center. Fine particle brown carbon optical absorption is estimated based on Mie calculations using direct size resolved measurements of chromophores in filter extracts. Size-resolved atmospheric aerosol samples were collected using a cascade impactor and analyzed for water-soluble organic carbon (WSOC), organic and elemental carbon (OC and EC), and solution light absorption spectra of water and methanol extracts. Methanol extracts were more light-absorbing than water extracts for all size ranges and wavelengths. Absorption refractive indices of the organic extracts were calculated from solution measurements for a range of wavelengths and used with Mie theory to predict the light absorption by fine particles comprised of these components, under the assumption that brown carbon and other aerosol components were externally mixed. For all three sites, chromophores were predominately in the accumulation mode with an aerodynamic mean diameter of 0.5 μm, an optically effective size range resulting in predicted particle light absorption being a factor of 2 higher than bulk solution absorption. Fine particle absorption was also measured with a Multi-Angle Absorption Photometer (MAAP) and seven-wavelength Aethalometer. Scattering-corrected aethalometer and MAAP absorption were in good agreement at 670 nm and Mie-estimated absorption based on size-resolved EC data were within 30% of these optical instruments. When applied

  6. Size-resolved measurements of brown carbon and estimates of their contribution to ambient fine particle light absorption based on water and methanol extracts

    Directory of Open Access Journals (Sweden)

    J. Liu

    2013-07-01

    Full Text Available Light absorbing organic carbon, often termed brown carbon, has the potential to significantly contribute to the visible light absorption budget, particularly at shorter wavelengths. Currently, the relative contributions of particulate brown carbon to light absorption, as well as the sources of brown carbon are poorly understood. With this in mind field measurements were made at both urban (Atlanta, and rural (Yorkville sites in Georgia. Measurements in Atlanta were made at both a central site and a road side site adjacent to a main highway near the city center. Fine particle brown carbon optical absorption is estimated based on Mie calculations using direct size resolved measurements of chromophores in filter extracts. Size-resolved atmospheric aerosol samples were collected using a cascade impactor and analyzed for water-soluble organic carbon (WSOC, organic and elemental carbon (OC and EC, and solution light absorption spectra of water and methanol extracts. Methanol extracts were more light-absorbing than water extracts for all size ranges and wavelengths. Absorption refractive indices of the organic extracts were calculated from solution measurements for a range of wavelengths and used with Mie theory to predict the light absorption by fine particles comprised of these components, under the assumption that brown carbon and other aerosol components were externally mixed. For all three sites, chromophores were predominately in the accumulation mode with an aerodynamic mean diameter of 0.5 μm, an optically effective size range resulting in predicted particle light absorption being a factor of 2 higher than bulk solution absorption. Fine particle absorption was also measured with a Multi-Angle Absorption Photometer (MAAP and seven-wavelength Aethalometer. Scattering-corrected aethalometer and MAAP absorption were in good agreement at 670 nm and Mie-estimated absorption based on size-resolved EC data were within 30% of these optical instruments

  7. Mechanical Particle Coating Using Polymethacrylate Nanoparticle Agglomerates for the Preparation of Controlled Release Fine Particles: the Relationship between Coating Performance and the Characteristics of Various Polymethacrylates.

    Science.gov (United States)

    Kondo, Keita; Kato, Shinsuke; Niwa, Toshiyuki

    2017-09-09

    We aimed to understand the factors controlling mechanical particle coating using polymethacrylate. The relationship between coating performance and the characteristics of polymethacrylate powders was investigated. First, theophylline crystals were treated using a mechanical powder processor to obtain theophylline spheres (spray freeze drying to produce colloidal agglomerates. Finally, mechanical particle coating was performed by mixing theophylline spheres and polymethacrylate agglomerates using the processor. The agglomerates were broken under mechanical stress to coat the spheres effectively. The coating performance of polymethacrylate agglomerates tended to increase as their pulverization progressed. Differences in the grindability of the agglomerates were attributed to differences in particle structure, resulting from consolidation between colloidal particles. High-grindability agglomerates exhibited higher pulverization as their glass transition temperature (Tg) increased and the further pulverization promoted coating. We therefore conclude that the minimization of polymethacrylate powder by pulverization is an important factor in mechanical particle coating using polymethacrylate with low deformability. Meanwhile, when product temperature during coating approaches Tg of polymer, polymethacrylate was soften to show high coating performance by plastic deformation. The effective coating by this mechanism may be accomplished by adjusting the temperature in the processor to the Tg. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Surface Modification of Fine Particle by Plasma Grafting in a Circulating Fluidized Bed Reactor under Reduced Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sounghee [Woosuk University, Jinchon (Korea, Republic of)

    2015-10-15

    A plasma surface modification of powders has been carried out in a circulating fluidized bed reactor under reduced pressure. Polystyrene (PS) particles treated by plasma are grafted with polyethylene glycol (PEG) on the surface. The virgin, plasma-treated and grafted powders were characterized by DPPH method, FTIR, SEM and contact angle meter. The plasma-treated PS powders have well formed peroxide on the surface, By PEG grafting polymerization, PEG is well grafted and dispersed on the surface of the plasma-treated PS powders. The PEG-g-PS particle was successfully synthesized using the plasma circulating fluidized bed reactor under reduced pressure.

  9. Introduction of a Population Balance Based Design Problem in a Particle Science and Technology Course for Chemical Engineers

    Science.gov (United States)

    Ehrman, Sheryl H.; Castellanos, Patricia; Dwivedi, Vivek; Diemer, R. Bertrum

    2007-01-01

    A particle technology design problem incorporating population balance modeling was developed and assigned to senior and first-year graduate students in a Particle Science and Technology course. The problem focused on particle collection, with a pipeline agglomerator, Cyclone, and baghouse comprising the collection system. The problem was developed…

  10. 77 FR 65310 - Additional Air Quality Designations for the 2006 24-Hour Fine Particle National Ambient Air...

    Science.gov (United States)

    2012-10-26

    ... Ambient Air Quality Standards AGENCY: Environmental Protection Agency (EPA). ACTION: Supplemental... particle (PM 2.5 ) national ambient air quality standards (NAAQS) air quality designations for the Ak-Chin... Federal Register NAAQS National Ambient Air Quality Standards NTTAA National Technology...

  11. Particle deposition in a child respiratory tract model: in vivo regional deposition of fine and ultrafine aerosols in baboons.

    Science.gov (United States)

    Albuquerque-Silva, Iolanda; Vecellio, Laurent; Durand, Marc; Avet, John; Le Pennec, Déborah; de Monte, Michèle; Montharu, Jérôme; Diot, Patrice; Cottier, Michèle; Dubois, Francis; Pourchez, Jérémie

    2014-01-01

    To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region) of radioactive polydisperse aerosols ([d16-d84], equal to [0.15 µm-0.5 µm], [0.25 µm-1 µm], or [1 µm-9 µm]). Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm-9 µm] aerosol (72% ± 17%). The [0.15 µm-0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84% ± 4%). Airborne particles in the range of [0.25 µm-1 µm] showed an intermediate deposition pattern, with 49% ± 8% in the extrathoracic region and 51% ± 8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm-9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes.

  12. Particle deposition in a child respiratory tract model: in vivo regional deposition of fine and ultrafine aerosols in baboons.

    Directory of Open Access Journals (Sweden)

    Iolanda Albuquerque-Silva

    Full Text Available To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region of radioactive polydisperse aerosols ([d16-d84], equal to [0.15 µm-0.5 µm], [0.25 µm-1 µm], or [1 µm-9 µm]. Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm-9 µm] aerosol (72% ± 17%. The [0.15 µm-0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84% ± 4%. Airborne particles in the range of [0.25 µm-1 µm] showed an intermediate deposition pattern, with 49% ± 8% in the extrathoracic region and 51% ± 8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm-9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes.

  13. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house.

    Science.gov (United States)

    Singer, B C; Delp, W W; Black, D R; Walker, I S

    2016-12-05

    This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM2.5 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

  14. Ultrafine and fine particle formation in a naturally ventilated office as a result of reactions between ozone and scented products

    DEFF Research Database (Denmark)

    Toftum, Jørn; Dijken, F. v.

    2003-01-01

    occurring in such offices, air fresheners or scented cleaners may react with ozone to form secondary organic aerosols (SOA). The tested air fresheners were relatively small sources of SOA with detectable increases occurring only in the ultrafine particle number concentration. With the cleaner, also...

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

    Science.gov (United States)

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

  16. Determination of time- and size-dependent fine particle emission with varied oil heating in an experimental kitchen.

    Science.gov (United States)

    Li, Shuangde; Gao, Jiajia; He, Yiqing; Cao, Liuxu; Li, Ang; Mo, Shengpeng; Chen, Yunfa; Cao, Yaqun

    2017-01-01

    Particulate matter (PM) from cooking has caused seriously indoor air pollutant and aroused risk to human health. It is urged to get deep knowledge of their spatial-temporal distribution of source emission characteristics, especially ultrafine particles (UFPcooking oils are auto dipped water to simulate cooking fume under heating to 265°C to investigate PM emission and decay features between 0.03 and 10μm size dimension by electrical low pressure impactor (ELPI) without ventilation. Rapeseed and sunflower produced high PM2.5 around 6.1mg/m(3), in comparison with those of soybean and corn (5.87 and 4.65mg/m(3), respectively) at peak emission time between 340 and 460sec since heating oil, but with the same level of particle numbers 6-9×10(5)/cm(3). Mean values of PM1.0/PM2.5 and PM2.5/PM10 at peak emission time are around 0.51-0.66 and 0.23-0.29. After 15min naturally deposition, decay rates of PM1.0, PM2.5 and PM10 are 13.3%-29.8%, 20.1%-33.9% and 41.2%-54.7%, which manifest that PM1.0 is quite hard to decay than larger particles, PM2.5 and PM10. The majority of the particle emission locates at 43nm with the largest decay rate at 75%, and shifts to a larger size between 137 and 655nm after 15min decay. The decay rates of the particles are sensitive to the oil type. Copyright © 2016. Published by Elsevier B.V.

  17. Vertical profiles of fine and coarse aerosol particles over Cyprus: Comparison between in-situ drone measurements and remote sensing observations

    Science.gov (United States)

    Mamali, Dimitra; Marinou, Eleni; Pikridas, Michael; Kottas, Michael; Binietoglou, Ioannis; Kokkalis, Panagiotis; Tsekeri, Aleksandra; Amiridis, Vasilis; Sciare, Jean; Keleshis, Christos; Engelmann, Ronny; Ansmann, Albert; Russchenberg, Herman W. J.; Biskos, George

    2017-04-01

    Vertical profiles of the aerosol mass concentration derived from light detection and ranging (lidar) measurements were compared to airborne dried optical particle counter (OPC MetOne; Model 212) measurements during the INUIT-BACCHUS-ACTRIS campaign. The campaign took place in April 2016 and its main focus was the study of aerosol dust particles. During the campaign the NOA Polly-XT Raman lidar located at Nicosia (35.08° N, 33.22° E) was providing round-the-clock vertical profiles of aerosol optical properties. In addition, an unmanned aerial vehicle (UAV) carrying an OPC flew on 7 days during the first morning hours. The flights were performed at Orounda (35.1018° N, 33.0944° E) reaching altitudes of 2.5 km a.s.l, which allows comparison with a good fraction of the recorded lidar data. The polarization lidar photometer networking method (POLIPHON) was used for the estimation of the fine (non-dust) and coarse (dust) mode aerosol mass concentration profiles. This method uses as input the particle backscatter coefficient and the particle depolarization profiles of the lidar at 532 nm wavelength and derives the aerosol mass concentration. The first step in this approach makes use of the lidar observations to separate the backscatter and extinction contributions of the weakly depolarizing non-dust aerosol components from the contributions of the strongly depolarizing dust particles, under the assumption of an externally mixed two-component aerosol. In the second step, sun photometer retrievals of the fine and the coarse modes aerosol optical thickness (AOT) and volume concentration are used to calculate the associated concentrations from the extinction coefficients retrieved from the lidar. The estimated aerosol volume concentrations were converted into mass concentration with an assumption for the bulk aerosol density, and compared with the OPC measurements. The first results show agreement within the experimental uncertainty. This project received funding from the

  18. Ice nucleation properties of fine ash particles from the Eyjafjallajökull eruption in April 2010

    Directory of Open Access Journals (Sweden)

    I. Steinke

    2011-12-01

    Full Text Available During the eruption of the Eyjafjallajökull volcano in the south of Iceland in April/May 2010, about 40 Tg of ash mass were emitted into the atmosphere. It was unclear whether volcanic ash particles with d < 10 μm facilitate the glaciation of clouds. Thus, ice nucleation properties of volcanic ash particles were investigated in AIDA (Aerosol Interaction and Dynamics in the Atmosphere cloud chamber experiments simulating atmospherically relevant conditions. The ash sample that was used for our experiments had been collected at a distance of 58 km from the Eyjafjallajökull during the eruption period in April 2010. The temperature range covered by our ice nucleation experiments extended from 219 to 264 K, and both ice nucleation via immersion freezing and deposition nucleation could be observed. Immersion freezing was first observed at 252 K, whereas the deposition nucleation onset lay at 242 K and RHice =126%. About 0.1% of the volcanic ash particles were active as immersion freezing nuclei at a temperature of 249 K. For deposition nucleation, an ice fraction of 0.1% was observed at around 233 K and RHice =116%. Taking ice-active surface site densities as a measure for the ice nucleation efficiency, volcanic ash particles are similarly efficient ice nuclei in immersion freezing mode (ns,imm ~ 109 m−2 at 247 K compared to certain mineral dusts. For deposition nucleation, the observed ice-active surface site densities ns,dep were found to be 1011 m−2 at 224 K and RHice =116%. Thus, volcanic ash particles initiate deposition nucleation more efficiently than Asian and Saharan dust but appear to be poorer ice nuclei than ATD particles. Based on the experimental data, we have derived ice-active surface site densities as a function of temperature for immersion freezing and of relative humidity over ice and temperature for

  19. The relationship between aerosol particles chemical composition and optical properties to identify the biomass burning contribution to fine particles concentration: a case study for São Paulo city, Brazil.

    Science.gov (United States)

    de Miranda, Regina Maura; Lopes, Fabio; do Rosário, Nilton Évora; Yamasoe, Marcia Akemi; Landulfo, Eduardo; de Fatima Andrade, Maria

    2016-12-01

    The air quality in the Metropolitan Area of São Paulo (MASP) is primarily determined by the local pollution source contribution, mainly the vehicular fleet, but there is a concern about the role of remote sources to the fine mode particles (PM2.5) concentration and composition. One of the most important remote sources of atmospheric aerosol is the biomass burning emissions from São Paulo state's inland and from the central and north portions of Brazil. This study presents a synergy of different measurements of atmospheric aerosol chemistry and optical properties in the MASP in order to show how they can be used as a tool to identify particles from local and remote sources. For the clear identification of the local and remote source contribution, aerosol properties measurements at surface level were combined with vertical profiles information. Over 15 days in the austral winter of 2012, particulate matter (PM) was collected using a cascade impactor and a Partisol sampler in São Paulo City. Mass concentrations were determined by gravimetry, black carbon concentrations by reflectance, and trace element concentrations by X-ray fluorescence. Aerosol optical properties were studied using a multifilter rotating shadowband radiometer (MFRSR), a Lidar system and satellite data. Optical properties, concentrations, size distributions, and elemental composition of atmospheric particles were strongly related and varied according to meteorological conditions. During the sampling period, PM mean mass concentrations were 17.4 ± 10.1 and 15.3 ± 6.9 μg/m(3) for the fine and coarse fractions, respectively. The mean aerosol optical depths at 415 nm and Ångström exponent (AE) over the whole period were 0.29 ± 0.14 and 1.35 ± 0.11, respectively. Lidar ratios reached values of 75 sr. The analyses of the impacts of an event of biomass burning smoke transport to the São Paulo city revealed significant changing on local aerosol concentrations and optical parameters

  20. Science education reform in an elementary school: An investigation of collaboration and inquiry in a school with an emphasis on language arts and fine arts

    Science.gov (United States)

    Martini, Mariana

    This investigation was framed within the science education reform, which proposes to change the way science is taught and promotes the implementation of inquiry-based teaching approaches. The implementation of inquiry science teaching represents a move away from traditional didactic teaching styles, a transition that requires change in the assumptions underlying the philosophy of traditional science instruction. Another theme in the reform literature is the establishment of collaboration between teachers and researchers or scientists as a way to implement reform practices. Situated within this reform climate, this research aimed to investigate science education at an elementary school with a history of implementing reform ideas in the areas of language arts and fine arts. I employed an ethnographic methodology to examine the nature of a teacher-researcher relationship in the context of the school's culture and teachers' practices. The findings indicate that change was not pervasive. Reform ideas were implemented only in the areas of language arts and fine arts. Situated within a district that promoted an accountability climate, the school disregarded science education and opposed the use of constructivist-based pedagogies, and did not have a strong science program. Since science was not tested, teachers spent little (if any) time teaching science. All participants firmly perceived the existence of several barriers to the implementation of inquiry: (a) lack of time: teachers spent excessive time to prepare students for tests, (b) nature of science teaching: materials and set preparation, (c) lack of content knowledge, (d) lack of pedagogical content knowledge, and (e) lack of opportunities to develop professional knowledge. In spite of the barriers, the school had two assets: an outdoor facility and two enthusiastic teachers who were lead science teachers, in spite of the their lack of content and pedagogical science knowledge. Collaboration between the researcher

  1. Quantum-mechanical relaxation model for characterization of fine particles magnetic dynamics in an external magnetic field

    Science.gov (United States)

    Mischenko, I.; Chuev, M.

    2016-12-01

    Principal difference of magnetic nanoparticles from the bulk matter which cannot be ignored when constructing upon them combined metamaterials and modern devices is the essential influence on their behavior thermal fluctuations of the environment. These disturbances lead to specific distributions of the particles characteristics and to stochastic reorientations of their magnetic moments. On the basis of quantum-mechanical representation of the particle possessing intrinsic magnetic anisotropy and being placed onto the external magnetic field we developed general approach to describe equilibrium magnetization curves and relaxation Mössbauer spectra of magnetic nanoparticles for diagnostics of magnetic nanomaterials in the whole temperature or external field ranges. This approach has universal character and may be applied not only to the systems under thermal equilibrium, but may in principle describe macroscopic dynamical phenomena such as magnetization reversal.

  2. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Black, Douglas R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-12-01

    This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration produced indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM2.55 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5. Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

  3. The Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) on the New Horizons Mission

    CERN Document Server

    McNutt, Ralph L; Gurnee, Reid S; Hill, Matthew E; Cooper, Kim A; Andrews, G Bruce; Keath, Edwin P; Krimigis, Stamatios M; Mitchell, Donald G; Tossman, Barry; Bagenal, Fran; Boldt, John D; Bradley, Walter; Devereux, William S; Ho, George C; Jaskulek, Stephen E; LeFevere, Thomas W; Malcom, Horace; Marcus, Geoffrey A; Hayes, John R; Moore, G Ty; Williams, Bruce D; Wilson, Paul; Brown, L E; Kusterer, M; Vandegriff, J

    2007-01-01

    The Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) comprises the hardware and accompanying science investigation on the New Horizons spacecraft to measure pick-up ions from Pluto's outgassing atmosphere. To the extent that Pluto retains its characteristics similar to those of a "heavy comet" as detected in stellar occultations since the early 1980s, these measurements will characterize the neutral atmosphere of Pluto while providing a consistency check on the atmospheric escape rate at the encounter epoch with that deduced from the atmospheric structure at lower altitudes by the ALICE, REX, and SWAP experiments on New Horizons. In addition, PEPSSI will characterize any extended ionosphere and solar wind interaction while also characterizing the energetic particle environment of Pluto, Charon, and their associated system. First proposed for development for the Pluto Express mission in September 1993, what became the PEPSSI instrument went through a number of development stages to meet the...

  4. Precipitated calcium carbonate (PCC - cellulose composite fillers: Effects of PCC particle structure on the production and properties of uncoated fine paper

    Directory of Open Access Journals (Sweden)

    Paulapuro, H.

    2007-02-01

    Full Text Available This work examines the precipitation of PCC – pulp composite fillers with varying crystal habits and their effects on the papermaking properties of printing and writing paper. Colloidal (c-PCC, rhombohedral (r-PCC, and scalenohedral types (s-PCC of composite PCCs were produced and compared with commercial reference PCCs. Scanning electron micros-copy showed the c-PCC to be a high-surface-area nano-structured PCC. The rhombohedral composite was formed in clusters like a spider-web structure. Under similar experimental conditions, composite PCC was formed as individual ellipsoidal crystals and some of the particles had malformed structure, in contrast to the structured reference s-PCC. The co-precipitation and the structure of PCC significantly influence the forming, consolidation, and properties of paper, as well as its perform-ance in printing.Composite c-PCC showed the highest retention during forming. At higher filler contents, dewatering was reduced significantly with handsheets containing s- and r-PCC composite fillers. Colloidal composite hand-sheets showed the lowest tensile index and internal bond strength, while the rhombohedral composite gave the highest z-directional bond strength. Compared with the traditional reference samples containing commercial PCCs, paper with s- and r-composites had significantly higher density but similar light scattering ability. Addition of fibrillar fines to fine paper increased print rub fastness significantly in both laser and inkjet printed samples.

  5. Influence of fine process particles enriched with metals and metalloids on Lactuca sativa L. leaf fatty acid composition following air and/or soil-plant field exposure.

    Science.gov (United States)

    Schreck, Eva; Laplanche, Christophe; Le Guédard, Marina; Bessoule, Jean-Jacques; Austruy, Annabelle; Xiong, Tiantian; Foucault, Yann; Dumat, Camille

    2013-08-01

    We investigate the effect of both foliar and root uptake of a mixture of metal(loid)s on the fatty acid composition of plant leaves. Our objectives are to determine whether both contamination pathways have a similar effect and whether they interact. Lactuca sativa L. were exposed to fine process particles enriched with metal(loid)s in an industrial area. Data from a first experiment were used to conduct an exploratory statistical analysis which findings were successfully cross-validated by using the data from a second one. Both foliar and root pathways impact plant leaf fatty acid composition and do not interact. Z index (dimensionless quantity), weighted product of fatty acid concentration ratios was built up from the statistical analyses. It provides new insights on the mechanisms involved in metal uptake and phytotoxicity. Plant leaf fatty acid composition is a robust and fruitful approach to detect and understand the effects of metal(loid) contamination on plants.

  6. 回水中的微细粒矿物资源化利用%THE RESOURCE UTILIZATION OF TINY-FINE-PARTICLE MINERAL IN THE WATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    孙立; 邓政斌

    2012-01-01

    The about 25 % of lead and zinc in suspension ultra-fine particles produced from water treatment system during mineral processing of a kind of complex refractory lead-zinc ore is recovered by the approach of mixing certain ratio of lead sulfide concentrate, thus the metal mineral resource utilization of lead and zinc is further improved.%云南某复杂难选铅锌矿水处理系统中的悬浮微细粒中铅锌之和为25%左右,采用按一定配比混入硫化铅精矿的方法进行回收,铅锌金属资源化利用程度进一步提高.

  7. Source identification and seasonal variation of polycyclic aromatic hydrocarbons associated with atmospheric fine and coarse particles in the Metropolitan Area of Porto Alegre, RS, Brazil

    Science.gov (United States)

    Teixeira, Elba Calesso; Agudelo-Castañeda, Dayana M.; Fachel, Jandyra Maria Guimarães; Leal, Karen Alam; Garcia, Karine de Oliveira; Wiegand, Flavio

    2012-11-01

    The purpose of the present study was to evaluate the polycyclic aromatic hydrocarbons (PAHs) in fine (PM2.5) and coarse particles (PM2.5-10) in an urban and industrial area in the Metropolitan Area of Porto Alegre (MAPA), Brazil. Sixteen U.S. Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs) were measured. Filters containing ambient air particulate were extracted with dichloromethane using Soxhlet. Extracts were later analyzed, for determining PAH concentrations, using a gaseous chromatograph coupled with a mass spectrometer (GC-MS). The polycyclic aromatic hydrocarbons (PAHs) were more concentrated in PM2.5 with an average of 70% of total PAHs in the MAPA. The target PAH apportionment among the main emission sources was carried out by diagnostic PAH concentration ratios, and principal component analysis (PCA). PAHs with higher molecular weight showed higher percentages in the fine particles in the MAPA. Based on the diagnostic ratios and PCA analysis, it may be concluded that the major contribution of PAHs was from vehicular sources (diesel and gasoline), especially in the PM2.5 fraction, as well as coal and wood burning. The winter/summer ratio in the PM2.5 and PM2.5-10 fractions in the MAPA was 3.1 and 1.8, respectively, revealing the seasonal variation of PAHs in the two fractions. The estimated toxicity equivalent factor (TEF), used to assess the contribution of the carcinogenic potency, confirms a significant presence of the moderately active carcinogenic PAHs BaP and DahA in the samples collected in the MAPA.

  8. Effect of selective catalytic reduction (SCR) on fine particle emission from two coal-fired power plants in China

    Science.gov (United States)

    Li, Zhen; Jiang, Jingkun; Ma, Zizhen; Wang, Shuxiao; Duan, Lei

    2015-11-01

    Nitrogen oxides (NOx) emission abatement of coal-fired power plants (CFPPs) requires large-scaled installation of selective catalytic reduction (SCR), which would reduce secondary fine particulate matter (PM2.5) (by reducing nitrate aerosol) in the atmosphere. However, our field measurement of two CFPPs equipped with SCR indicates a significant increase of SO42- and NH4+ emission in primary PM2.5, due to catalytic enhancement of SO2 oxidation to SO3 and introducing of NH3 as reducing agent. The subsequent formation of (NH4)2SO4 or NH4HSO4 aerosol is commonly concentrated in sub-micrometer particulate matter (PM1) with a bimodal pattern. The measurement at the inlet of stack also showed doubled primary PM2.5 emission by SCR operation. This effect should therefore be considered when updating emission inventory of CFPPs. By rough estimation, the enhanced primary PM2.5 emission from CFPPs by SCR operation would offset 12% of the ambient PM2.5 concentration reduction in cities as the benefit of national NOx emission abatement, which should draw attention of policy-makers for air pollution control.

  9. Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 yr study

    Science.gov (United States)

    Cusack, M.; Pérez, N.; Pey, J.; Alastuey, A.; Querol, X.

    2013-02-01

    The chemical composition and sources of ambient fine particulate matter (PM1) over a period of 2.5 yr for a regional background site in the western Mediterranean are presented in this work. Major components (such as SO12-, NO3-, NH4+, organic and elemental carbon) and trace elements were analysed and the emission sources affecting PM1 were determined using Positive Matrix Factorisation (PMF). Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. Sources of sub-micron particles were determined by Principal Component Analysis (PCA). The mean PM1 concentration for the measurement period was 8.9 μg m-3, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μg m-3). A clear seasonal variation was recorded with higher PM1 concentrations in summer (11.2 μg m-3) compared to winter (6.6 μg m-3). This summer increase was due to elevated levels of sulphate and OM. Six sources were identified by PMF: secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. The daily variations of these sources were also determined, whereby the typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source

  10. Speculative Physics: the Ontology of Theory and Experiment in High Energy Particle Physics and Science Fiction

    CERN Document Server

    Lee, Clarissa Ai Ling

    2014-01-01

    The dissertation brings together approaches across the fields of physics, critical theory, literary studies, philosophy of physics, sociology of science, and history of science to synthesize a hybrid approach for instigating more rigorous and intense cross-disciplinary interrogations between the sciences and the humanities. There are two levels of conversations going on in the dissertation; at the first level, the discussion is centered on a critical historiography and philosophical implications of the discovery Higgs boson in relation to its position at the intersection of old (current) and the potential for new possibilities in quantum physics; I then position my findings on the Higgs boson in connection to the double-slit experiment that represents foundational inquiries into quantum physics, to demonstrate the bridge between fundamental physics and high energy particle physics. The conceptualization of the variants of the double-slit experiment informs the aforementioned critical comparisons. At the secon...

  11. Using multiple continuous fine particle monitors to characterize tobacco, incense, candle, cooking, wood burning, and vehicular sources in indoor, outdoor, and in-transit settings

    Science.gov (United States)

    Ott, Wayne R.; Siegmann, Hans C.

    This study employed two continuous particle monitors operating on different measurement principles to measure concentrations simultaneously from common combustion sources in indoor, outdoor, and in-transit settings. The pair of instruments use (a) photo-charging (PC) operating on the principle ionization of fine particles that responds to surface particulate polycyclic aromatic hydrocarbons (PPAHs), and (b) diffusion charging (DC) calibrated to measure the active surface area of fine particles. The sources studied included: (1) secondhand smoke (cigarettes, cigars, and pipes), (2) incense (stick and cone), (3) candles used as food warmers, (4) cooking (toasting bread and frying meat), (5) fireplaces and ambient wood smoke, and (6) in-vehicle exposures traveling on California arterials and interstate highways. The ratio of the PC to the DC readings, or the PC/DC ratio, was found to be different for major categories of sources. Cooking, burning toast, and using a "canned heat" food warmer gave PC/DC ratios close to zero. Controlled experiments with 10 cigarettes averaged 0.15 ng mm -2 (ranging from 0.11 to 0.19 ng mm -2), which was similar to the PC/DC ratio for a cigar, although a pipe was slightly lower (0.09 ng mm -2). Large incense sticks had PC/DC ratios similar to those of cigarettes and cigars. The PC/DC ratios for ambient wood smoke averaged 0.29 ng mm -2 on 6 dates, or about twice those of cigarettes and cigars, reflecting a higher ratio of PAH to active surface area. The smoke from two artificial logs in a residential fireplace had a PC/DC ratio of 0.33-0.35 ng mm -2. The emissions from candles were found to vary, depending on how the candles were burned. If the candle flickered and generated soot, a higher PC/DC ratio resulted than if the candle burned uniformly in still air. Inserting piece of metal into the candle's flame caused high PPAH emissions with a record PC/DC reading of 1.8 ng mm -2. In-vehicle exposures measured on 43- and 50-min drives on a

  12. Gas/aerosol-ash interaction in volcanic plumes: New insights from surface analyses of fine ash particles

    Science.gov (United States)

    Delmelle, Pierre; Lambert, Mathieu; Dufrêne, Yves; Gerin, Patrick; Óskarsson, Niels

    2007-07-01

    The reactions occurring between gases/aerosols and silicate ash particles in volcanic eruption plumes remain poorly understood, despite the fact that they are at the origin of a range of volcanic, environmental, atmospheric and health effects. In this study, we apply X-ray photoelectron spectroscopy (XPS), a surface-sensitive technique, to determine the chemical composition of the near-surface region (2-10 nm) of nine ash samples collected from eight volcanoes. In addition, atomic force microscopy (AFM) is used to image the nanometer-scale surface structure of individual ash particles isolated from three samples. We demonstrate that rapid acid dissolution of ash occurs within eruption plumes. This process is favoured by the presence of fluoride and is believed to supply the cations involved in the deposition of sulphate and halide salts onto ash. AFM imaging also has permitted the detection of extremely thin (< 10 nm) coatings on the surface of ash. This material is probably composed of soluble sulphate and halide salts mixed with sparingly soluble fluoride compounds. The surface approach developed here offers promising aspects for better appraising the role of gas/aerosol-ash interaction in dictating the ability of ash to act as sinks for various volcanic and atmospheric chemical species as well as sources for others.

  13. Observations of residual submicron fine aerosol particles related to cloud and fog processing during a major pollution event in Beijing

    Science.gov (United States)

    Li, Zhengqiang; Eck, Tom; Zhang, Ying; Zhang, Yuhuan; Li, Donghui; Li, Li; Xu, Hua; Hou, Weizhen; Lv, Yang; Goloub, Philippe; Gu, Xingfa

    2014-04-01

    Residual aerosols, the particles left behind after droplet evaporation, are important tracers for aerosols processed by cloud and/or fog. Based on ground-based CIMEL sun-sky radiometer measurements during an extreme winter pollution event in Beijing, we present observations of the decrease of residual aerosol with dissipation of cloud and an unusual case of residual aerosol increase after partial dissipation of fog. This unusual increase might be an important mechanism for the haze growth in polluted regions. The aerosol single scattering albedo is found to increase with the increase of residual aerosol. We also find that residual aerosol dominated cases with significant water content gain can occur in a short time (e.g. one hour) with the increase of aerosol volume size and decrease of particle number. A lognormal residual aerosol size distribution model is proposed based on sun-sky radiometer measurements with center peak radius at 0.44 micron and geometric standard deviation of about 1.49.

  14. Genotoxicity, inflammation and physico-chemical properties of fine particle samples from an incineration energy plant and urban air

    DEFF Research Database (Denmark)

    Sharma, Anoop Kumar; Jensen, Keld Alstrup; Rank, Jette

    2007-01-01

    Airborne particulate matter (PM) was sampled by use of an electrostatic sampler in an oven hall and a receiving hall in a waste-incineration energy plant, and from urban air in a heavy-traffic street and from background air in Copenhagen. PM was sampled for 1-2 weeks, four samples at each site...... by the comet assay - were determined after 24-h incubations with human A549 lung epithelial cells. The PM2.5 concentration was about twofold greater in the oven hall than in the receiving hall. The particle size distribution in the receiving hall was similar to that in street air (maximum mode at about 25 nm...... from all four sites caused similar levels of DNA damage in A549 cells; only the oven hall samples gave results that were statistically significantly different from those obtained with street-air samples. The receiving hall and the urban air samples were similarly inflammatory (relative IL-8 m...

  15. Trace metals in atmospheric fine particles in one industrial urban city: spatial variations, sources, and health implications.

    Science.gov (United States)

    Zhou, Shengzhen; Yuan, Qi; Li, Weijun; Lu, Yaling; Zhang, Yangmei; Wang, Wenxing

    2014-01-01

    Trace metals in PM2.5 were measured at one industrial site and one urban site during September, 2010 in Ji'nan, eastern China. Individual aerosol particles and PM2.5 samples were collected concurrently at both sites. Mass concentrations of eleven trace metals (i.e., Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, and Pb) and one metalloid (i.e., As) were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The result shows that mass concentrations of PM2.5 (130 microg/m3) and trace metals (4.03 microg/m3) at the industrial site were 1.3 times and 1.7 times higher than those at the urban site, respectively, indicating that industrial activities nearby the city can emit trace metals into the surrounding atmosphere. Fe concentrations were the highest among all the measured trace metals at both sites, with concentrations of 1.04 microg/m 3 at the urban site and 2.41 microg/m3 at the industrial site, respectively. In addition, Pb showed the highest enrichment factors at both sites, suggesting the emissions from anthropogenic activities existed around the city. Correlation coefficient analysis and principal component analysis revealed that Cu, Fe, Mn, Pb, and Zn were originated from vehicular traffic and industrial emissions at both sites; As, Cr, and part of Pb from coal-fired power plant; Ba and Ti from natural soil. Based on the transmission electron microscopy analysis, we found that most of the trace metals were internally mixed with secondary sulfate/organic particles. These internally mixed trace metals in the urban air may have different toxic abilities compared with externally mixed trace metals.

  16. Pulmonary toxicity of inhaled nanoscale and fine zinc oxide particles: mass and surface area as an exposure metric.

    Science.gov (United States)

    Ho, Meng; Wu, Kuen-Yuh; Chein, Hung-Min; Chen, Lung-Chi; Cheng, Tsun-Jen

    2011-12-01

    The total surface area is known to be an effective exposure metric for predicting the lung toxicity of low solubility nanoparticles (NPs). However, if NPs are dissolved quickly enough in the lungs, the mass may be correlated with the toxicity. Recent studies have found that the toxicity of zinc oxide (ZnO) NPs was caused by the release of zinc ions. Thus, we hypothesized that mass could be used as an exposure metric for the toxicity of ZnO NPs. Healthy Sprague-Dawley rats were exposed to a low, moderate, or high dose of 35 and 250 nm ZnO particles or filtered air. Bronchoalveolar lavage fluid was collected to determine lung inflammation, injury and oxidative stress. The lung inflammation induced by ZnO particles according to different concentration metrics, including number, mass and surface area, was compared. The mass concentration was significantly correlated with the percentage of neutrophils (R(2) = 0.84), number of neutrophils (R(2) = 0.84) and total cells (R(2) = 0.73). Similarly, surface area concentration was significantly correlated with the percentage of neutrophils (R(2) = 0.94), number of neutrophils (R(2) = 0.81) and total cells (R(2) = 0.76). There was no correlation between the number and lung inflammation. We found that both mass and surface area were effective as metrics for the toxicity of ZnO NPs, although only surface area was previously indicated to be an effective metric. Our results are also consistent with recent study results that ZnO NPs and released zinc ions may play a role mediating the toxicity of NPs.

  17. Approach for simultaneous measurement of two-dimensional angular distribution of charged particles. III. Fine focusing of wide-angle beams in multiple lens systems

    Science.gov (United States)

    Matsuda, Hiroyuki; Daimon, Hiroshi; Tóth, László; Matsui, Fumihiko

    2007-04-01

    This paper provides a way of focusing wide-angle charged-particle beams in multiple lens systems. In previous papers [H. Matsuda , Phys. Rev. E 71, 066503 (2005); 74, 036501 (2006)], it was shown that an ellipsoidal mesh, combined with electrostatic lenses, enables correction of spherical aberration over wide acceptance angles up to ±60° . In this paper, practical situations where ordinary electron lenses are arranged behind the wide-angle electrostatic lenses are taken into account using ray tracing calculation. For practical realization of the wide-angle lens systems, the acceptance angle is set to ±50° . We note that the output beams of the wide-angle electrostatic lenses have somewhat large divergence angles which cause unacceptable or non-negligible spherical aberration in additional lenses. A solution to this problem is presented showing that lens combinations to cancel spherical aberration are available, whereby wide-angle charged-particle beams can be finely focused with considerably reduced divergence angles less than ±5° .

  18. Magnetic behavior of bulk and fine particles of RCr{sub 2}Si{sub 2}C (R = La, Ce) compounds: possible magnetic ordering from Cr

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, K; Iyer, Kartik K; Sampathkumaran, E V, E-mail: sampath@mailhost.tifr.res.i [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

    2010-07-28

    The magnetic behavior of the quaternary compounds, RCr{sub 2}Si{sub 2}C (R = La, Ce), has been investigated by magnetization (M) and heat-capacity (C) measurements (1.8-300 K) in the bulk polycrystals and nano forms (<1 {mu}m) obtained by high-energy balling. Our finding is that Cr appears to exhibit magnetic ordering of an itinerant type at low temperatures (<20 K) in the bulk form, as inferred from a combined look at all the data. The magnetic ordering gets gradually suppressed with increasing milling time. Evidence for a mixed-valence state of Ce for the bulk form is obtained from the tendency of magnetic susceptibility to exhibit a maximum above 300 K. However, this feature vanishes in the nano form, which exhibits a Curie-Weiss behavior above 200 K as though Ce tends towards trivalency in these fine particles; in addition, there is a weak upturn in C/T below 10 K in the bulk, which becomes very prominent in the milled Ce-based specimens at lower temperatures, as though heavy-fermion behavior gets stronger in smaller particles.

  19. Seasonal variations of ultra-fine and submicron aerosols in Taipei, Taiwan: implications for particle formation processes in a subtropical urban area

    Science.gov (United States)

    Cheung, H. C.; Chou, C. C.-K.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Lee, C. S. L.

    2016-02-01

    The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultra-fine particles (UFPs, d ≤ 100 nm) and submicron particles (PM1, d ≤ 1 µm) in an east Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at TARO (Taipei Aerosol and Radiation Observatory), an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC) and the particle number size distribution (PSD) with size range of 4-736 nm. The results indicated that the mass concentration of PM1 was elevated during cold seasons with a peak level of 18.5 µg m-3 in spring, whereas the highest concentration of UFPs was measured in summertime with a mean of 1.64 µg m-3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents of PM1. The seasonal median of total PNCs ranged from 13.9 × 103 cm-3 in autumn to 19.4 × 103 cm-3 in spring. Median concentrations for respective size distribution modes peaked in different seasons. The nucleation-mode PNC (N4 - 25) peaked at 11.6 × 103 cm-3 in winter, whereas the Aitken-mode (N25 - 100) and accumulation-mode (N100 - 736) PNC exhibited summer maxima at 6.0 × 103 and 3.1 × 103 cm-3, respectively. The change in PSD during summertime was attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributed to the growth of aerosol particles in the atmosphere. In addition, clear photochemical production of particles was observed, mostly in the summer season, which was characterized by average particle growth and formation rates of 4.0 ± 1.1 nm h-1 and 1.4 ± 0.8 cm-3 s-1

  20. Size-resolved measurements of brown carbon in water and methanol extracts and estimates of their contribution to ambient fine-particle light absorption

    Science.gov (United States)

    Liu, J.; Bergin, M.; Guo, H.; King, L.; Kotra, N.; Edgerton, E.; Weber, R. J.

    2013-12-01

    Light absorbing organic carbon, often called brown carbon, has the potential to significantly contribute to the visible light-absorption budget, particularly at shorter wavelengths. Currently, the relative contributions of particulate brown carbon to light absorption, as well as the sources of brown carbon, are poorly understood. With this in mind size-resolved direct measurements of brown carbon were made at both urban (Atlanta), and rural (Yorkville) sites in Georgia. Measurements in Atlanta were made at both a representative urban site and a road-side site adjacent to a main highway. Fine particle absorption was measured with a multi-angle absorption photometer (MAAP) and seven-wavelength Aethalometer, and brown carbon absorption was estimated based on Mie calculations using direct size-resolved measurements of chromophores in solvents. Size-resolved samples were collected using a cascade impactor and analyzed for water-soluble organic carbon (WSOC), organic and elemental carbon (OC and EC), and solution light-absorption spectra of water and methanol extracts. Methanol extracts were more light-absorbing than water extracts for all size ranges and wavelengths. Absorption refractive indices of the organic extracts were calculated from solution measurements for a range of wavelengths and used with Mie theory to predict the light absorption by fine particles comprised of these components, under the assumption that brown carbon and other aerosol components were externally mixed. For all three sites, chromophores were predominately in the accumulation mode with an aerodynamic mean diameter of 0.5 μm, an optically effective size range resulting in predicted particle light absorption being a factor of 2 higher than bulk solution absorption. Mie-predicted brown carbon absorption at 350 nm contributed a significant fraction (20 to 40%) relative to total light absorption, with the highest contributions at the rural site where organic to elemental carbon ratios were

  1. Ozone and fine particle in the western Yangtze River Delta: an overview of 1-yr data at the SORPES station

    Directory of Open Access Journals (Sweden)

    A. J. Ding

    2013-01-01

    Full Text Available This work presents an overview of 1-yr measurements of ozone (O3 and fine particular matter (PM2.5 and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES, in the western part of the Yangtze River Delta (YRD in East China. O3 and PM2.5 showed distinguished seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and also indicates a substantial formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1-yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e. along the Nanjing-Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the middle-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region, especially for the burning episode days. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving

  2. Genotoxicity, inflammation and physico-chemical properties of fine particle samples from an incineration energy plant and urban air.

    Science.gov (United States)

    Sharma, Anoop Kumar; Jensen, Keld Alstrup; Rank, Jette; White, Paul A; Lundstedt, Staffan; Gagne, Remi; Jacobsen, Nicklas R; Kristiansen, Jesper; Vogel, Ulla; Wallin, Håkan

    2007-10-04

    Airborne particulate matter (PM) was sampled by use of an electrostatic sampler in an oven hall and a receiving hall in a waste-incineration energy plant, and from urban air in a heavy-traffic street and from background air in Copenhagen. PM was sampled for 1-2 weeks, four samples at each site. The samples were extracted and examined for mutagenicity in Salmonella typhimurium strains TA98, YG1041 and YG5161, for content of inorganic elements and for the presence of eight polycyclic aromatic hydrocarbons. The induction of IL-6 and IL-8 mRNA expression and the presence of DNA damage - tested by the comet assay - were determined after 24-h incubations with human A549 lung epithelial cells. The PM(2.5) concentration was about twofold greater in the oven hall than in the receiving hall. The particle size distribution in the receiving hall was similar to that in street air (maximum mode at about 25nm), but the distribution was completely different in the oven hall (maximum mode at about 150nm). Also chemically, the samples from the oven hall were highly different from the other samples. PM extracts from the receiving hall, street and background air were more mutagenic than the PM extracts from the oven hall. PM from all four sites caused similar levels of DNA damage in A549 cells; only the oven hall samples gave results that were statistically significantly different from those obtained with street-air samples. The receiving hall and the urban air samples were similarly inflammatory (relative IL-8 mRNA expression), whereas the oven hall did not cause a statistically significant increase in IL-8 mRNA expression. A principal component analysis separated the oven hall and the receiving hall by the first principal component. These two sites were separated from street and background air with the second principal component. Several clusters of constituents were identified. One cluster consisted of all the polycyclic aromatic hydrocarbons (PAH), several groups of metals and one

  3. Concentrations and solubility of trace elements in fine particles at a mountain site, southern China: regional sources and cloud processing

    Science.gov (United States)

    Li, T.; Wang, Y.; Li, W. J.; Chen, J. M.; Wang, T.; Wang, W. X.

    2015-08-01

    The concentrations and solubility of twelve trace elements in PM2.5 at Mt. Lushan, southern China, were investigated during the summer of 2011 and the spring of 2012. The average PM2.5 mass was 55.2 ± 20.1 μg m-3 during the observation period. Temporal variations of all trace elements including total and water-soluble fractions with several dust storm spikes in total fractions of Al and Fe were observed. The enrichment factor (EF) values were 1 order of magnitude higher for the water-soluble fractions versus the total fractions of trace elements. Four major emission sources, namely nonferrous metal mining and smelting (for Cr, As, Ba and parts of Zn), coal combustion (for Pb, Zn, Se, Cu and Mn), crustal materials (for Al and Fe) and municipal solid waste incineration (for Cd and Mo), were classified by principal component analysis (PCA). Trajectory cluster analysis and the potential source contribution function (PSCF) consistently identified the Yangtze River delta (YRD), the Pearl River delta (PRD), and the neighbouring provinces of Mt. Lushan as the major source regions and transport pathways for anthropogenic elements. Northern China was identified as a major source region for crustal elements. It should be noted that apart from the YRD, the area around Mt. Lushan has become the most significant contributor to the solubility of most trace elements. Element solubility can be partially determined by emission sources. However, enhanced solubility of trace elements corresponding to increased concentrations of sulfate after the occurrence of cloud events indicated significant effects of cloud processing on aerosol element dissolution. Metal particles mixed with sulfate in cloud droplet residues were further investigated through transmission electron microscopy (TEM) analysis. Irreversible alteration of particle morphology by cloud processing was confirmed to be highly responsible for the enhancement of trace element solubility. The findings from this study imply an

  4. A pilot study to assess ground-level ambient air concentrations of fine particles and carbon monoxide in urban Guatemala.

    Science.gov (United States)

    Shendell, Derek G; Naeher, Luke P

    2002-11-01

    Ambient concentrations and the elemental composition of particles less than 2.5 microm in diameter (PM2.5), as well as carbon monoxide (CO) concentrations, were measured at ground-level in three Guatemalan cities in summer 1997: Guatemala City, Quetzaltenango, and Antigua. This pilot study also included quantitative and qualitative characterizations of microenvironment conditions, e.g., local meteorology, reported elsewhere. The nondestructive X-ray fluorescence elemental analysis (XRF) of Teflon filters was conducted. The highest integrated average PM2.5. concentrations in an area (zona) of Guatemala City and Quetzaltenango were 150 microg m(-3) (zona 12) and 120 microg m(-3) (zona 2), respectively. The reported integrated average PM2.5 concentration for Antigua was 5 microg m(-3). The highest observed half-hour and monitoring period average CO concentrations in Guatemala City were 10.9 ppm (zona 8) and 7.2 ppm (zonas 8 and 10), respectively. The average monitoring period CO concentration in Antigua was 2.6 ppm. Lead and bromine concentrations were negligible, indicative of the transition to unleaded fuel use in cars and motorcycles. The XRF results suggested sources of air pollution in Guatemala, where relative rankings varied by city and by zonas within each city, were fossil fuel combustion emitting hydrocarbons, combustion of sulfurous conventional fuels, soil/roadway dust, farm/agricultural dust, and vehicles (evaportion of gas, parts' wear).

  5. Concentration, origin and health hazard from fine particle-bound PAH at three characteristic sites in Southern Poland.

    Science.gov (United States)

    Rogula-Kozłowska, Wioletta; Kozielska, Barbara; Klejnowski, Krzysztof

    2013-09-01

    Suspended particles with the aerodynamic diameters not greater than 2.5 μm (PM2.5) and 1 μm (PM1, sub-fraction of PM2.5) were sampled at three sites: an urban background site, rural background site, and urban traffic site in southern Poland. In total, there were 240 samples taken within 02.08.2009-27.12.2010. Fifteen polycyclic aromatic hydrocarbons (PAH) were determined in each dust fraction. The averages of the concentration of total PAH (ΣPAH) and of particular PAH, as well as the share of carcinogenic PAH in total PAH (ΣPAHcarc/ΣPAH), carcinogenic equivalent, mutagenic equivalent, and TCDD-toxic equivalent appeared high compared to other areas in the world. Their high values express the significance of health hazard from PM and PM-bound PAH in southern Poland. The diagnostic ratios suggest that PM-bound PAH originate from municipal (PM1-2.5) and vehicular (PM1) combustion.

  6. Impact of the composition of combustion generated fine particles on epithelial cell toxicity: influences of metals on metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Okeson, C.D.; Riley, M.R.; Fernandez, A.; Wendt, J.O.L. [University of Arizona, Tucson, AZ (USA). Dept. of Agriculture & Biosystems Engineering

    2003-06-01

    Inhaled airborne particulate matter (PM) represents a potentially significant health hazard to humans. PM generated from the combustion of fuel oils and coals contain a number of water-soluble transition metals including Fe, V, and Zn. The authors evaluated the impact of PM types with varying composition collected from the combustion of oils and coals on the health and metabolism of lung cell cultures. Three colorimetric assays (sulforhodamine B (SRB), Janus green, and MTT) were adapted to quantify the impact of PM on rat lung alveolar type 11 epithelial cells (RLE-6TN cells). The PM toxicity metrics evaluated were inhibition of cell proliferation (SRB and Janus green) and inhibition of cellular metabolism (MTT). Cell proliferation is inhibited in a consistent dose-dependent manner by PM concentrations from 25 to 250 {mu}g/ml. At a level of 100 {mu}g/ml, oil-derived PM diminishes cell metabolism by as much as 40% relative to controls; the degree of inhibition is strongly dependent on PM particle size and metal content. Conversely, coal-derived PM at the same dosage diminishes cell metabolism by no more than 20% relative to controls. All three assays provide highly repeatable results and consistent toxicity rankings of the PMs evaluated. Overall, metabolic inhibition as measured by the MTT assay was deemed the most appropriate metric for PM toxicity, primarily due to its applicability with in vivo-like confluent cell monolayers.

  7. Imaging the fine-scale structure of the cellular actin cytoskeleton by Single Particle Tracking and Atomic Force Microscopy

    Science.gov (United States)

    Mustata, Gina-Mirela

    It has been proposed that diffusion in the plasma membrane of eukaryotic cells it is compartmentalized due to the interaction with the underlying actin-based membrane skeleton that comes into close proximity to the lipid bilayer. The cytoskeleton is a dynamic structure that maintains cell shape, enables cell motion, and plays important roles in both intra-cellular transport and cellular division. We show here the evidence of plasma membrane compartmentalization using Single Particle Tracking (SPT) and Atomic Force Microscopy (AFM) imaging. SPT of Quantum dot labeled lipid in the plasma membrane of live normal rat kidney cells show compartments ranging from 325 nm to 391 nm depending on the sampling time. Using AFM imaging of live NRK cell in the presence of phalloidin, the membrane compartmentalization it is visible with the average size of the compartments of 325 +/- 10 nm (the main peak is centered at 260 nm). Further, the underlying membrane skeleton in fixed cells was directly imaged after partial removal of the plasma membrane to reveal size of the membrane skeleton meshwork of 339 +/- 10 nm. A new method of measuring the characteristics of the actin meshwork was proposed. Probing the local compliance of the plasma membrane through the deflection of a soft AFM cantilever we can expect that the stiffness of the membrane will be higher at locations directly above a cortical actin. This new method provided information about the structure of the skeletal meshwork of neuronal cell body predicting an average compartment size of about 132 nm. This was confirmed through SPT of QD-lipid incorporated into the neuronal cell membrane.

  8. Impact of the composition of combustion generated fine particles on epithelial cell toxicity: influences of metals on metabolism.

    Science.gov (United States)

    Okeson, Carl D; Riley, Mark R; Fernandez, Art; Wendt, Jost O L

    2003-06-01

    Inhaled airborne particulate matter (PM) represents a potentially significant health hazard to humans. Exposure to PM strongly correlates with pulmonary inflammation and incidences of severe respiratory distress, including increased hospital admissions for breathing disorders, asthma, emphysema, and chronic bronchitis. PM generated from the combustion of fuel oils and coals contain a number of water-soluble transition metals including Fe, V, and Zn. We have evaluated the impact of PM types with varying composition collected from the combustion of oils and coals on the health and metabolism of lung cell cultures. Three colorimetric assays (sulforhodamine B (SRB), Janus green, and MTT) have been adapted to quantify the impact of PM on rat lung alveolar type II epithelial cells (RLE-6TN cells). The PM toxicity metrics evaluated were inhibition of cell proliferation (SRB and Janus green) and inhibition of cellular metabolism (MTT). Cell proliferation is inhibited in a consistent dose-dependent manner by PM concentrations from 25 to 250 microg/ml. At a level of 100 microg/ml, oil-derived PM diminishes cell metabolism by as much as 40% relative to controls; the degree of inhibition is strongly dependent on PM particle size and metal content. Conversely, coal-derived PM at the same dosage diminishes cell metabolism by no more than 20% relative to controls. All three assays provide highly repeatable results and consistent toxicity rankings of the PMs evaluated. Overall, metabolic inhibition as measured by the MTT assay was deemed the most appropriate metric for PM toxicity, primarily due to its applicability with in vivo-like confluent cell monolayers.

  9. Measurements of energetic particle radiation in transit to Mars on the Mars Science Laboratory.

    Science.gov (United States)

    Zeitlin, C; Hassler, D M; Cucinotta, F A; Ehresmann, B; Wimmer-Schweingruber, R F; Brinza, D E; Kang, S; Weigle, G; Böttcher, S; Böhm, E; Burmeister, S; Guo, J; Köhler, J; Martin, C; Posner, A; Rafkin, S; Reitz, G

    2013-05-31

    The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011, and for most of the 253-day, 560-million-kilometer cruise to Mars, the Radiation Assessment Detector made detailed measurements of the energetic particle radiation environment inside the spacecraft. These data provide insights into the radiation hazards that would be associated with a human mission to Mars. We report measurements of the radiation dose, dose equivalent, and linear energy transfer spectra. The dose equivalent for even the shortest round-trip with current propulsion systems and comparable shielding is found to be 0.66 ± 0.12 sievert.

  10. Transport, biomass burning, and in-situ formation contribute to fine particle concentrations at a remote site near Grand Teton National Park

    Science.gov (United States)

    Schurman, M. I.; Lee, T.; Desyaterik, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L.

    2015-07-01

    Ecosystem health and visibility degradation due to fine-mode atmospheric particles have been documented in remote areas and motivate particle characterization that can inform mitigation strategies. This study explores submicron (PM1) particle size, composition, and source apportionment at Grand Teton National Park using High-Resolution Time-of-Flight Aerosol Mass Spectrometer data with Positive Matrix Factorization and MODIS fire information. Particulate mass averages 2.08 μg/m3 (max = 21.91 μg/m3) of which 75.0% is organic; PMF-derived Low-Volatility Oxygenated Organic Aerosol (LV-OOA) averages 61.1% of PM1 (or 1.05 μg/m3), with sporadic but higher-concentration biomass burning (BBOA) events contributing another 13.9%. Sulfate (12.5%), ammonium (8.7%), and nitrate (3.8%) are generally low in mass. Ammonium and sulfate have correlated time-series and association with transport from northern Utah and the Snake River Valley. A regionally disperse and/or in situ photochemical LV-OOA source is suggested by 1) afternoon concentration enhancement not correlated with upslope winds, anthropogenic NOx, or ammonium sulfate, 2) smaller particle size, higher polydispersity, and lower levels of oxidation during the day and in comparison to a biomass burning plume inferred to have traveled ∼480 km, and 3) lower degree of oxidation than is usually observed in transported urban plumes and alpine sites with transported anthropogenic OA. CHN fragment spectra suggest organic nitrogen in the form of nitriles and/or pyridines during the day, with the addition of amine fragments at night. Fires near Boise, ID may be the source of a high-concentration biomass-burning event on August 15-16, 2011 associated with SW winds (upslope from the Snake River Valley) and increased sulfate, ammonium, nitrate, and CHN and CHON fragments (nominally, amines and organonitrates). Comparison to limited historical data suggests that the amounts and sources of organics and inorganics presented here

  11. Regular Changes in the Fine Structure of Histograms Revealed in the Experiments with Collimators which Isolate Beams of Alpha-Particles Flying at Certain Directions

    Directory of Open Access Journals (Sweden)

    Shnoll S. E.

    2009-04-01

    Full Text Available As was shown in the works of 1951–1983, the fine structure of distributions of the re- sults of measurements of processes of diverse nature is not casual. The changes in the shape of histograms corresponding to the distributions were called “macroscopic fluctu- ations”. The universal character of the phenomenon and its independence of the nature of the process studied were demonstrated for various processes: biochemical and chem- ical reactions, movement of latex particles in the electric field, proton transverse relax- ation in the inhomogeneous magnetic field, discharge in the neon-tube RC-generator and radioactive decay of various - and -isotopes. Since 1982, the main object chosen to study macroscopic fluctuations has been -decay. The choice was based on the pro- cess being a priori independent of trivial factors and the possibility to conduct continu- ous long-term automatic measurements while storing the results in a computer archive (database. Started in 1982, these measurements have been carrying on, as unceasingly as possible, until now. Since July 2000, the measurements are conducted using devices designed by one of the coauthors of this review, I. A. Rubinstein. Application of these devices (especially, detectors with collimators which isolate beams of -particles fly- ing at certain directions, along with the use of Edwin Pozharsky’s computer program, which eases histogram comparing by the expert, has allowed us to reveal a number of fundamentally new regularities. In the review, we describe these regularities, device constructions, and the methods of measurement and analysis of the results obtained.

  12. Space science applications for conducting polymer particles: synthetic mimics for cosmic dust and micrometeorites.

    Science.gov (United States)

    Fielding, Lee A; Hillier, Jon K; Burchell, Mark J; Armes, Steven P

    2015-12-11

    Over the last decade or so, a range of polypyrrole-based particles have been designed and evaluated for space science applications. This electrically conductive polymer enables such particles to efficiently acquire surface charge, which in turn allows their acceleration up to the hypervelocity regime (>1 km s(-1)) using a Van de Graaff accelerator. Either organic latex (e.g. polystyrene or poly(methyl methacrylate)) or various inorganic materials (such as silica, olivine or pyrrhotite) can be coated with polypyrrole; these core-shell particles are useful mimics for understanding the hypervelocity impact ionisation behaviour of micro-meteorites (a.k.a. cosmic dust). Impacts on metal targets at relatively low hypervelocities (10 km s(-1)) generate predominately atomic species, since many more chemical bonds are cleaved if the particles impinge with higher kinetic energy. Such fundamental studies are relevant to the calibration of the cosmic dust analyser (CDA) onboard the Cassini spacecraft, which was designed to determine the chemical composition of Saturn's dust rings. Inspired by volcanism observed for one of the Jupiter's moons (Io), polypyrrole-coated sulfur-rich latexes have also been designed to help space scientists understand ionisation spectra originating from sulfur-rich dust particles. Finally, relatively large (20 μm diameter) polypyrrole-coated polystyrene latexes have proven to be useful for understanding the extent of thermal ablation of organic projectiles when fired at ultralow density aerogel targets at up to 6.1 km s(-1) using a Light Gas Gun. In this case, the sacrificial polypyrrole overlayer simply provides a sensitive spectroscopic signature (rather than a conductive overlayer), and the scientific findings have important implications for the detection of organic dust grains during the Stardust space mission.

  13. Thermally assisted mechanical dewatering (TAMD) of suspensions of fine particles: analysis of the influence of the operating conditions using the response surface methodology.

    Science.gov (United States)

    Mahmoud, Akrama; Fernandez, Aurora; Chituchi, Toma-Mihai; Arlabosse, Patricia

    2008-08-01

    Thermally assisted mechanical dewatering (TAMD) is a new process for energy-efficient liquid/solids separation which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions (temperature dewatering parameter and an excellent indicator of the extent of TAMD. In this study, a two-factor central composite rotatable design was used to establish the optimum conditions for the TAMD of suspensions of fine particles. Significant regression models, describing changes on final dry solids content with respect to independent variables, were established with regression coefficients (usually called determination coefficients), R(2), greater than 80%. Experiments were carried out on a laboratory filtration/compression cell, firstly on different compressible materials: synthetic mineral suspensions such as talc and synthetic organic suspensions such as cellulose, and then on industrial materials, such as bentonite sludge provided by Soletanche Bachy Company. Experiment showed that the extent of TAMD for a given material is particularly dependent on their physical and chemical properties but also on processing parameters.

  14. PREFACE: 1st Conference on Light and Particle Beams in Materials Science 2013 (LPBMS2013)

    Science.gov (United States)

    Kumai, Reiji; Murakami, Youichi

    2014-04-01

    From 29-31 August 2013, the 1st International Conference on Light and Particle Beams in Materials Science, LPBMS 2013, took place in the Tsukuba International Congress Center in the city of Tsukuba, Japan. The conference was a continuation of the international series Synchrotron Radiation in Materials Science (SRMS), which started in 1994. The last one, SRMS-7, was held in Oxford UK 11-14 July 2010, where the International Advisory Committee (IAC) recommended the conference be enlarged to incorporate Materials Research from Neutron, Muon, and Slow Positron Sources, as well as the science emerging from Synchrotron Light Sources. The conference brought together contributions from academics and industrial researchers with a diverse background and experience from the physics, chemistry and engineering communities. The topics covered in the LPBMS2013 include strongly correlated electron systems, magnetism and magnetic materials, soft matter, interface and surface defects, catalysts, biomaterials, and ceramics. In the 3-day scientific program, the conference consisted of 9 plenary talks, 33 invited talks, 20 oral presentations, and 126 poster presentations. We are pleased to publish the proceedings of the LPBMS2013 in this volume of Journal of Physics: Conference Series. This volume contains 58 papers representing the work that was presented and discussed at the conference. We hope that this volume will promote further development of this interdisciplinary materials research emerging from synchrotron light, neutron, muon, and slow positron sciences. Finally, we would like to thank the International Advisory Committee (Chair: Professor G N Greaves), sponsors, all the participants and contributors for making possible this international meeting of researchers. Reiji Kumai & Youichi Murakami Conference photograph Details of the program and organizing committees are available in the pdf

  15. Inorganic ions in ambient fine particles over a National Park in central India: Seasonality, dependencies between SO42-, NO3-, and NH4+, and neutralization of aerosol acidity

    Science.gov (United States)

    Kumar, Samresh; Sunder Raman, Ramya

    2016-10-01

    Twelve hour integrated ambient fine particles (PM2.5) were collected over an Van Vihar National Park (VVNP), in Bhopal, Central India. Samples were collected on filter substrates every-other-day for two years (2012 and 2013). In addition to PM2.5 mass concentration, water soluble inorganic ions (WSIIs) were also measured. Further, on-site meteorological parameters including temperature, wind speed, wind direction, relative humidity, rainfall and atmospheric pressure were recorded. During 2012, the average PM2.5 concentration was 40 ± 31 μgm-3 while during 2013 it was 48 ± 50 μgm-3. Further, in about 20% of the samples the 12 h integrated fine PM mass exceeded the daily (24 h) average standards (60 μgm-3). This observation suggests that the PM2.5 mass concentration at the study site is likely to be in violation of the National Ambient Air Quality Standard (NAAQS), India. During the study period the sum of three major ions (SO42-, NO3-, and NH4+) accounted for 19.4% of PM2.5 mass on average. Air parcel back trajectory ensembles revealed that emissions from thermal power plants were likely to be the main regional source of particulate SO42- and NO3- measured over VVNP. Further, local traffic activities appeared to have no significant impact on the concentrations of PM2.5 and its WSIIs constituents, as revealed by a day-of-the-week analysis. PM2.5 mass, SO42-, NO3-, and NH4+ showed a pronounced seasonal trend with winter (Jan, Feb) and post-monsoon (Oct, Nov, Dec) highs and pre-monsoon (Mar, Apr, May) and monsoon (Jun, Jul, Aug, Sep) lows, during both 2012 and 2013. Further, when the sum of SO42- and NO3- constituted greater than 90% of water soluble inorganic anions by mass, they were linearly dependent on one another and moderately anti-correlated (r2 = 0.60). The molar ratios of NH4+ and non-sea salt SO42- were examined to understand the aerosol neutralization mechanisms and particulate NO3- formation. An assessment of these ratios and subsequent analyses

  16. Removal of fine particles in wet flue gas desulphurization system by heterogeneous condensation%湿法脱硫系统中应用蒸汽相变技术脱除细颗粒

    Institute of Scientific and Technical Information of China (English)

    鲍静静; 杨林军; 颜金培; 刘锦辉; 宋士娟

    2009-01-01

    通过在脱硫塔进口烟气、塔内脱硫液进口上方添加适量蒸汽等措施,在湿法烟气脱硫(WFGD)系统中进行了利用蒸汽相变原理高效脱除细颗粒的试验研究.考察了采用CaCO_3, Na_2CO_3, NH_3·H_2O等3种不同脱硫剂时,WFGD系统对细颗粒的脱除性能及其脱硫剂、蒸汽添加量、液气比(体积比)、脱硫塔进口气液温差等的影响,并进行了添加蒸汽和喷雾化水的对比试验.结果表明,由于形成无机盐气溶胶细颗粒,采用CaCO_3, NH_3·H_2O脱硫剂时,WFGD系统对细颗粒的脱除效果明显差于Na_2CO_3脱硫剂;在WFGD系统中应用蒸汽相变原理可显著促进细颗粒的脱除,在蒸汽添加量为0.05 kg/m~3时,细颗粒数浓度脱除效率可增至60%~70%以上;液气比的影响与脱硫塔内是否存在蒸汽相变有关;提高脱硫塔进口气液温差有利于细颗粒脱除;烟气温度较高时,利用雾化液滴的蒸发替代添加蒸汽也能显著促进细颗粒的脱除.%A novel process to remove fine particles with high efficiency by heterogeneous condensation in a wet flue gas desulphurization (WFGD) system is presented. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO_2 absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the scrubbing liquid inlet of the scrubber, respectively. The condensational grown droplets were then removed by the scrubbing liquid and a high-efficiency demister. The results show that the effectiveness of the WFGD system for removal of fine particles is related to the SO_2 absorbent employed. When using CaCO_3 and NH_3 · H_2O to remove SO_2 from flue gas, the fine particle removal efficiencies are lower than those using Na_2CO_3 and water as result of the formation of aerosol particles in the limestone and ammonia-based FGD processes. The performance of the WFGD system for removal of fine particles is significantly

  17. Knock Resistance and Fine Particle Emissions for Several Biomass-Derived Oxygenates in a Direct-Injection Spark-Ignition Engine

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliff, Matthew A.; Burton, Jonathan; Sindler, Petr; Christensen, Earl; Fouts, Lisa; Chupka, Gina M.; McCormick, Robert L.

    2016-04-01

    Several high octane number oxygenates that could be derived from biomass were blended with gasoline and examined for performance properties and their impact on knock resistance and fine particle emissions in a single cylinder direct-injection spark-ignition engine. The oxygenates included ethanol, isobutanol, anisole, 4-methylanisole, 2-phenylethanol, 2,5-dimethyl furan, and 2,4-xylenol. These were blended into a summertime blendstock for oxygenate blending at levels ranging from 10 to 50 percent by volume. The base gasoline, its blends with p-xylene and p-cymene, and high-octane racing gasoline were tested as controls. Relevant gasoline properties including research octane number (RON), motor octane number, distillation curve, and vapor pressure were measured. Detailed hydrocarbon analysis was used to estimate heat of vaporization and particulate matter index (PMI). Experiments were conducted to measure knock-limited spark advance and particulate matter (PM) emissions. The results show a range of knock resistances that correlate well with RON. Molecules with relatively low boiling point and high vapor pressure had little effect on PM emissions. In contrast, the aromatic oxygenates caused significant increases in PM emissions (factors of 2 to 5) relative to the base gasoline. Thus, any effect of their oxygen atom on increasing local air-fuel ratio was outweighed by their low vapor pressure and high double-bond equivalent values. For most fuels and oxygenate blend components, PMI was a good predictor of PM emissions. However, the high boiling point, low vapor pressure oxygenates 2-phenylethanol and 2,4-xylenol produced lower PM emissions than predicted by PMI. This was likely because they did not fully evaporate and combust, and instead were swept into the lube oil.

  18. Effect of particle size on the flux pinning properties of YBa2Cu3O7-δ thin films containing fine Y2O3 nanoprecipitates

    Science.gov (United States)

    Yamasaki, H.

    2016-06-01

    The magnetic-field angle dependence of the critical current density, J c(H, θ), was measured at various temperatures in co-evaporated YBa2Cu3O7-δ (YBCO) thin films. The YBCO films showed volcano-shaped J c(θ) peaks around H//ab, and J c(θ) peaks around H//c were not observed. Film A, deposited at a lower temperature than the commercial standard film B, showed lower J c values at high temperatures (T ≥ 60 K) compared with film B, although film A showed higher J c at T = 20 K. Plan-view transmission electron microscope observations revealed that films A and B contained a high density of fine Y2O3 nanoprecipitates. The modes in the distribution of their cross-sectional areas are 10-20 nm2 in film A and 20-30 nm2 in film B. Because of the smaller particle size, film A showed lower J c at high temperatures owing to the smaller elementary pinning force, f p, but showed higher J c at 20 K where the temperature-dependent coherence length ξ ab (T) was short (˜2 nm) and comparable with the radius of Y2O3 nanoparticles. Film A showed anisotropic scaling behavior at T = 70-80 K, and the T dependence of J c followed ˜(1 - T/T c) m (1 + T/T c)2 (m ≈ 2.5), which was expected from a simple flux-pinning model.

  19. Fine particles (PM2.5) at a CAWNET background site in Central China: Chemical compositions, seasonal variations and regional pollution events

    Science.gov (United States)

    Zhang, Fan; Cheng, Hai-rong; Wang, Zu-wu; Lv, Xiao-pu; Zhu, Zhong-min; Zhang, Gan; Wang, Xin-ming

    2014-04-01

    Fine particle (PM2.5) samples were collected at Jinsha (JSH), a regional background China Atmosphere Watch Network (CAWNET) site in Central China from March 2012 to March 2013. The mass concentrations of water-soluble inorganic ions (WSIIs), organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured. The average PM2.5 mass concentration was 48.7 ± 26.9 μg m-3, exceeding the Chinese National Ambient Air Quality Standards (NAAQS) (35 μg m-3), implying that PM2.5 is a pollutant of regional concern in Central China. The average concentrations of total WSIIs, OC and EC were 26.1 ± 18.8, 7.5 ± 3.5 and 0.7 ± 0.5 μg m-3, accounting for 53.5%, 15.1% and 1.5% of the PM2.5 concentrations at JSH, respectively. Clear seasonal variations in PM2.5 and the levels of its main chemical species were observed in the following order: winter > autumn > spring > summer. Backward air trajectory analysis and potential source contribution function (PSCF) analysis implied that the areas north and northeast of JSH contributed significantly to the levels of SO42-, NO3-, NH4+ and OC, while sandstorms originating from Mongolia and traveling across Northwest China may have contributed significantly to the levels of Na+, Ca2+, and Mg2+ in PM2.5 at JSH. Two pollution events, related to regional biomass burning and haze, respectively, were recorded at JSH during the sampling campaign.

  20. PROBA-V Energetic Particle Telescope instrument and its early science results

    Science.gov (United States)

    Cyamukungu, Mathias; O'Brien, Paul; Benck, Sylvie; Evans, Hugh; Nieminen, Petteri; Mazur, Joseph; Daly, Eamonn; Borisov, Stanislav

    The Energetic Particle Telescope (EPT) is a science-class instrument designed to measure contamination-free spectra of electrons (0.5 - 10 MeV), protons (9 - 300 MeV) and He-ions (38 - 1200 MeV) within a 52 deg. Field Of View (FOV) angle and a 149 cm(2) sr aperture geometrical factor. The instrument is modular and it can be in-flight configured so as to provide up to 19 energy channels per particle type. The EPT dimensions are 210 mm x 162 mm x 128 mm, the total mass is 4.6 kgs and its power consumption amounts to 5.6 Watts. The satellite PROBA-V was launched on the 7th May 2013 onto a sun-synchronous circular Low Earth Orbit at 820 km altitude and 98.7 deg. inclination. Its local time at descending node is 10:30. The EPT has been accommodated onto the S/C so as to get its boresight oriented Eastwards during local night time and Westwards during local day time. However, the East/West orientation has been modified during the commissioning phase to allow measurements of Pitch Angle Distribution (PAD). The latters were part of a plan aimed at validating the EPT hardware and the data analysis software. The EPT is currently acquiring data that are used for (i) cross-validation of radiation monitors or spectrometers, (ii) cross-validation of space radiation models, (iii) development of steady-state electron and proton flux models and (iv) space weather studies. The EPT validation results along with early results of the ongoing science studies are presented in this paper.

  1. Dust Aerosol Particle Size at the Mars Science Laboratory Landing Site

    Science.gov (United States)

    Vicente-Retortillo, Alvaro; Martínez, Germán; Renno, Nilton; Lemmon, Mark; de la Torre-Juárez, Manuel

    2017-04-01

    We have developed a new methodology to retrieve dust aerosol particle size from Mars Science Laboratory (MSL) observations [1]. We use photodiode output currents measured by the Rover Environmental Monitoring Station (REMS) UV sensor (UVS), ancillary data records (ADR) containing the geometry of the rover and the Sun, and values of the atmospheric opacity retrieved from Mastcam measurements. In particular, we analyze REMS UVS measurements when the Sun is blocked by the masthead and the mast of the rover since the behavior of the output currents during these shadow events depends on the dust phase function, which depends on particle size. The retrieved dust effective radii show a significant seasonal variability, ranging from 0.6 μm during the low opacity season (Ls = 60° - 140°) to 2 μm during the high opacity season (Ls = 180° - 360°). The relationship between atmospheric opacity and dust particle size indicates that dust-lifting events originate at various distances from Gale Crater. The external origin of high dust content events is consistent with the strong and persistent northerly and northwesterly winds at Gale Crater during the perihelion season centered around Ls = 270° [2]. From an interannual perspective, the general behavior of the particle size evolution in MY 31-32 is similar to that in MY 32-33, although some differences are noted. During the low opacity season (Ls = 60° - 140°), the retrieved dust effective radii in MY 33 are significantly lower than in MY 32. A larger contribution of water ice clouds to the total atmospheric opacity during the aphelion season of MY 33 can partially explain such a departure. Differences during the perihelion season are caused by interannual variability of enhanced opacity events. The determination of dust aerosol particle size is important to improve the accuracy of models in simulating the UV environment at the surface [3] and in predicting heating rates, which affect the atmospheric thermal and dynamical

  2. Analysis of Hazards and Countermeasures forPrevention and Control of Atmospheric Fine Particles Pollution%浅谈大气细颗粒物污染的危害及防治对策

    Institute of Scientific and Technical Information of China (English)

    刘巍巍

    2014-01-01

    Along with the rapid economic developmentand the increase of population ,the pollution discharge of industrial and mining enterprises has continuouslyincreased the burden of the atmospheric environment and aggravated the atmospheric fine particle pollution .This article analyzes the influences of atmospheric fine particles pollution on people's health and the causes ,and puts forward the control measures .%指出了随着经济的快速发展,工矿企业的污染排放增加了大气环境的负担,使得城市大气细颗粒物污染逐渐严重。就大气细颗粒物污染的产生及对人们健康的影响进行了分析,并提出了相应的治理措施。

  3. Decomposition of organic carbon in fine soil particles is likely more sensitive to warming than in coarse particles: an incubation study with temperate grassland and forest soils in northern China.

    Science.gov (United States)

    Ding, Fan; Huang, Yao; Sun, Wenjuan; Jiang, Guangfu; Chen, Yue

    2014-01-01

    It is widely recognized that global warming promotes soil organic carbon (SOC) decomposition, and soils thus emit more CO2 into the atmosphere because of the warming; however, the response of SOC decomposition to this warming in different soil textures is unclear. This lack of knowledge limits our projection of SOC turnover and CO2 emission from soils after future warming. To investigate the CO2 emission from soils with different textures, we conducted a 107-day incubation experiment. The soils were sampled from temperate forest and grassland in northern China. The incubation was conducted over three short-term cycles of changing temperature from 5°C to 30°C, with an interval of 5°C. Our results indicated that CO2 emissions from sand (>50 µm), silt (2-50 µm), and clay (soils. The temperature sensitivity of the CO2 emission from soil particles, which is expressed as Q10, decreased in the order clay>silt>sand. Our study also found that nitrogen availability in the soil facilitated the temperature dependence of SOC decomposition. A further analysis of the incubation data indicated a power-law decrease of Q10 with increasing temperature. Our results suggested that the decomposition of organic carbon in fine-textured soils that are rich in clay or silt could be more sensitive to warming than those in coarse sandy soils and that SOC might be more vulnerable in boreal and temperate regions than in subtropical and tropical regions under future warming.

  4. 细粒含量对粗粒土蠕变特性影响的试验研究%Experimental Research on Influence of Content of Fine Particles on Creep Properties of Coarse-grained Soil

    Institute of Scientific and Technical Information of China (English)

    王瑞甫

    2014-01-01

    粗粒土的蠕变特性是影响路堤本体长期沉降的重要性质。利用单轴压缩蠕变试验,并基于与试验结果相符的H-K蠕变模型,探讨细颗粒含量与蠕变参数之间的关系,分析砂质板岩粗粒土中细颗粒含量对其蠕变特性的影响规律。分析结果表明:细颗粒含量是影响粗粒土蠕变特性的重要因素;使用细颗粒含量为30%的粗粒土填料可控制路堤长期沉降。%The creep properties of coarse-grained soil are important properties affecting long-term settlement of embankments. This paper probes into the relationship between content of fine particles and creep parameters by means of uniaxial compression creep test and based on the H-k creep model compliant with test results, and analyzes the laws of influences of content of fine particles in coarse-grained soil of sandy slate. The analysis results show that the content of fine particles is an important factor affecting creep properties of coarse-grained soil;and use of coarse-grained soil fill with 30% content of fine particles can control long-term settlement of embankments.

  5. Science Results from Colorado Student Space Weather Experiment (CSSWE): Energetic Particle Distribution in Near Earth Environment

    Science.gov (United States)

    Li, Xinlin

    2013-04-01

    The Colorado Student Space Weather Experiment (CSSWE) is a 3-unit (10cm x 10cm x 30cm) CubeSat mission funded by the National Science Foundation, launched into a low-Earth, polar orbit on 13 September 2012 as a secondary payload under NASA's Educational Launch of Nanosatellites (ELaNa) program. The science objectives of CSSWE are to investigate the relationship of the location, magnitude, and frequency of solar flares to the timing, duration, and energy spectrum of solar energetic particles reaching Earth, and to determine the precipitation loss and the evolution of the energy spectrum of trapped radiation belt electrons. CSSWE contains a single science payload, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), which is a miniaturization of the Relativistic Electron and Proton Telescope (REPT) built at the Laboratory for Atmospheric and Space Physics for NASA/Van Allen Probes mission, which consists of two identical spacecraft, launched 30 August 2012, that traverse the heart of the radiation belts in a low inclination orbit. CSSWE's REPTile is designed to measure the directional differential flux of protons ranging from 10 to 40 MeV and electrons from 0.5 to >3.3 MeV. The commissioning phase was completed and REPTile was activated on 4 October 2012. The data are very clean, far exceeding expectations! A number of engineering challenges had to be overcome to achieve such clean measurements under the mass and power limits of a CubeSat. The CSSWE is also an ideal class project, providing training for the next generation of engineers and scientists over the full life-cycle of a satellite project.

  6. Impact property on fine particles from coal combustion in wet flue gas desulfurization process%湿法脱硫烟气中细颗粒物的变化特性

    Institute of Scientific and Technical Information of China (English)

    颜金培; 杨林军; 鲍静静

    2011-01-01

    Fine particles in flue gas before and after WFGD ( wet flue gas desulfurization) were sampled and measured by ELPI (electrical low pressure impactor). Fine particle concentrations and size distributions characteristics were obtained. And the microstructure and major element concentrations of particles were analyzed by SEM ( scanning electron microscopy) and EDS ( energy disperse spectroscopy), respectively. The results show that the removal efficiency of fine particles by WFGD is extremely low using NaOH and CaCO3 desulfurization, but particle number concentration has an obvious increase after ammonia desulfurization. Particles morphology structure and element contents have a great change after WFGD. The surfaces of fine particles from coal-fired may adsorb small particles to form roughness and aggregate structure. But it can be enwrapped by desulfurization reaction products to form a dense irregular block-like structure after CaCO3 desulfurization process. And fine particles are mostly of cube or prism crystal structure after ammonia desulfurization. The main elements of fine particles before WFGD are O, A1 and Si, however, the element content of S in particles is significantly increased after desulfurization, which increases from 1.33% to 10. 01%,19. 96% and 46. 64% after NaOH, CaCO3 and NH3 desulfurization respectively.%采用ELPI(电称低压冲击器)对WFGD(湿法烟气脱硫)前后烟气中的细颗粒进行采样分析,获得细颗粒浓度与粒径分布特性.对脱硫前后细颗粒形貌和主要元素进行SEM(扫描电镜)和EDS(能量色谱仪)分析.结果表明,NaOH和CaCO3脱硫后,WFGD系统对细颗粒脱除效率很低;氨法脱硫后WFGD出口颗粒数浓度明显增加;脱硫前后,细颗粒的形貌特征和元素组分会发生很大变化,洗涤前燃煤细颗粒表面容易吸附小颗粒而形成表面粗糙的团聚体结构;CaCO3脱硫后,细颗粒容易被脱硫反应产物连结或包裹而形成致密的不规则块状或

  7. Numerical simulation of fine particles dispersion in urban street canyon based on DPM model%街道峡谷内细微颗粒物扩散特性的DPM数值模拟

    Institute of Scientific and Technical Information of China (English)

    付志民; 孙在; 杨文俊; 谢小芳

    2011-01-01

    Based on the discrete phase model (DPM), a simulation was carried out to study fine particles dispersion and their concentration in different kinds of typical street canyon. In the simulation, a standard k-E two-equation model was used as turbulence model. The numerical results indicated that due to urban wind flow, the air in the street canyon presented vortex flow, dispersion and distribution of fine particles were changed. The concentration showed 'climbing wall effect'. The aspect ratio of street canyon had crucial effect on fine particle concentration distribution. Moreover, the concentration in street canyon with stepped-up notch configuration is lower than others.%应用离散相模型(DPM)对城市中典型的街道峡谷内细微颗粒污染物浓度场进行了模拟,计算湍流模型选择标准k-E双方程模型.计算结果表明,城市风场作用于街谷内导致涡旋流动,进而影响颗粒物的扩散分布.背风侧壁面颗粒物的浓度场呈现明显的“爬墙效应”.不同几何结构影响颗粒物的浓度场,递增型街谷模型更有利于颗粒污染物的扩散.

  8. Pre-Service Chemistry Teachers' Pedagogical Content Knowledge of the Nature of Science in the Particle Nature of Matter

    Science.gov (United States)

    Bektas, Oktay; Ekiz, Betul; Tuysuz, Mustafa; Kutucu, Elif Selcan; Tarkin, Aysegul; Uzuntiryaki-Kondakci, Esen

    2013-01-01

    This study investigated pre-service chemistry teachers' pedagogical content knowledge of the nature of science (NOS) in the content of the particle nature of matter. Qualitative research design was utilized. Data were collected from seven pre-service chemistry teachers (PCTs) by using open-ended questions, interviews, observations, lesson plans,…

  9. Fine coal particles separation by air-solid magnetic fluidization%气固磁场流态化分选细粒煤

    Institute of Scientific and Technical Information of China (English)

    宋树磊; 赵跃民; 骆振福; 唐利刚; 杨旭亮

    2012-01-01

    利用研制的横流式气固磁稳定流化床,以0.074~0.045 mm粒级磁铁矿粉和磁珠作为高密度和低密度分选介质,对6.0~0.5 mm细粒煤进行连续分选试验。结果表明:当处于稳定流化时,磁场气固流化床比普通气固流化床具有更宽的稳定操作气速范围;外加磁场使磁性颗粒沿磁力线形成平行磁链,增大了床层空隙率,形成了分布均匀的通道,气体通过时不会产生气泡,由此形成了稳定的散式气固磁场流化床;高密度分选和低密度分选的可能偏差分别为0.085,0.075 g/cm3。%Continuous separation tests of fine coal particles of 6. 0-0. 5 mm were done by a crossflow air-solid magneti- cally stabilized fluidized bed ( MSFB ), which used 0. 074-0. 045 mm magnetite powder and magnetite beads as medi- um of high and low density separation respectively. The results show that the range of steadily operational air velocity in air-solid magnetically fluidized beds is broader than that in standard air-solid fluidized beds when they are at stable fluidization. External magnetic field compels the magnetic grains to form parallel magnetic chains following the magnet- ic induction lines, which enlarge the bed voidage and form the uniform air channels. Air bubbles cannot be produced when the air flows through the channels, thus stable and particulate air-solid magnetically fluidized beds coming into being. The possible deviation of high and low density separation are 0. 085 and 0. 075 g/cm3 respectively.

  10. Regulating Drug Release Behavior and Kinetics from Matrix Tablets Based on Fine Particle-Sized Ethyl Cellulose Ether Derivatives: An In Vitro and In Vivo Evaluation

    Directory of Open Access Journals (Sweden)

    Kifayat Ullah Shah

    2012-01-01

    Full Text Available The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4 using PharmaTest dissolution apparatus at constant temperature of 37∘C±0.1. Similarity factor 2 was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including max, max and AUC0- were compared which showed an optimized max and max (<0.05. A good correlation was obtained between in vitro

  11. Emission factors of fine particles, carbonaceous aerosols and traces gases from road vehicles: Recent tests in an urban tunnel in the Pearl River Delta, China

    Science.gov (United States)

    Zhang, Yanli; Wang, Xinming; Li, Guanghui; Yang, Weiqiang; Huang, Zhonghui; Zhang, Zhou; Huang, Xinyu; Deng, Wei; Liu, Tengyu; Huang, Zuzhao; Zhang, Zhanyi

    2015-12-01

    Motor vehicles contribute primarily and secondarily to air quality problems due to fine particle (PM2.5) and ozone (O3) pollution in China's megacities. Characterizing vehicle emission with the rapid change of vehicle numbers and fleet compositions is vital for both bottom-up emission survey and top-down source apportioning. To obtain emission factors (EFs) of PM2.5, carbonaceous aerosols and trace gases for road vehicles, in urban Guangzhou we conducted a field campaign in 2014 in the Zhujiang Tunnel, a heavily burdened tunnel with about 40,000 motor vehicles passing through each of its two separated bores per day. PM2.5 and volatile organic compounds (VOCs) were sampled for offline analysis while trace gases including SO2, NOx and CO were measured online and in situ. An eddy covariance system with an integrated 3-D sonic anemometer was also adopted to measure CO2 and winds inside the tunnel. We recorded an average fleet composition of 61% light-duty gasoline vehicles (LDVs) + 12% heavy-duty diesel vehicles (HDVs) + 27% liquefied petroleum gas vehicles (LPGVs), and EFs of 82.7 ± 28.3, 19.3 ± 4.7 and 13.3 ± 3.3 mg veh-1 km-1, respectively, for PM2.5, organic carbon (OC) and elemental carbon (EC). These EFs were respectively 23.4%, 18.3% and 72.3% lower when compared to that measured in the same tunnel in 2004. EFs of PM2.5, OC and EC were higher at night time (148 ± 126, 29 ± 24 and 21 ± 18 mg veh-1 km-1, respectively) due to significantly elevated fractions of HDVs in the traffic fleets. An average ratio of OC to EC 1.45 from this tunnel study was much higher than that of ∼0.5 in previous tunnel studies. The EFs of SO2, NOx, CO, CO2 and NMHCs for road traffic were also obtained from our tunnel tests, and they were 20.7 ± 2.9, (1.29 ± 0.2)E+03, (3.10 ± 0.68)E+03, (3.90 ± 0.49)E+05, and 448 ± 39 mg veh-1 km-1, respectively.

  12. The elemental composition and origin of fine ambient particles in the largest Polish conurbation: first results from the short-term winter campaign

    Science.gov (United States)

    Majewski, Grzegorz; Rogula-Kozłowska, Wioletta

    2016-07-01

    Diurnal (24-h) samples of fine particulate matter (PM2.5, ambient particles with an aerodynamic diameter not greater than 2.5 μm) and soil samples were collected in an urban area in Warsaw, in winter. The samples were analysed for 24 elements with an Epsilon 5 spectrometer (PANalytical). The results were then arranged and compared with the results of research conducted earlier in Poland and other parts of the world. Afterwards, sources of ambient PM2.5 were identified and the share of each in the concentration of PM2.5 was evaluated by means of enrichment factor (EF) analysis, principal component analysis (PCA) and multi-linear regression analysis (MLRA). The results were interpreted using a detailed analysis of correlations between diurnal concentrations of PM2.5, PM2.5-elements, and of changes in meteorological conditions. The winter average ambient concentration of PM2.5 in Warsaw, was 10.7 ± 7.5 μg/m3 and was much lower than in the other sites in Poland. In Warsaw, regardless of the concentration of PM2.5, the concentrations of certain PM2.5-bound elements, mainly toxic, were high, e.g. the average ambient concentrations of PM2.5-bound Se, As, Co, V, Cd and Ni were 12.7 ± 30.5, 10.6 ± 34.4, 9.4 ± 13.7, 15.1 ± 32.7, 9.6 ± 22.2 and 3.5 ± 5.0 ng/m3, respectively. The elemental composition and concentrations of PM2.5 appeared to be influenced mainly by the anthropogenic emissions (energy production based on coal and biomass combustion, whose mean contribution to the concentration of PM2.5 was 18.4 %, and energy production based on oil combustion with a contribution of 9.9 % in PM2.5). A mixture of soil matter and road dust was also identified in PM2.5 (8 %). The mean contribution of traffic (exhaust) emissions to the concentration of PM2.5 in an urban area, selected as representative of the Warsaw conurbation, was assessed at 15.4 %.

  13. Regulating drug release behavior and kinetics from matrix tablets based on fine particle-sized ethyl cellulose ether derivatives: an in vitro and in vivo evaluation.

    Science.gov (United States)

    Shah, Kifayat Ullah; Khan, Gul Majid

    2012-01-01

    The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC) and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P) ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP) as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4) using PharmaTest dissolution apparatus at constant temperature of 37 °C ± 0.1. Similarity factor f(2) was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including C(max⁡), T(max⁡) and AUC(0-t) were compared which showed an optimized C(max⁡) and T(max⁡) (P < 0.05). A good correlation was obtained

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

    Institute of Scientific and Technical Information of China (English)

    王志兵; 李凯; 汪稔; 胡明鉴

    2016-01-01

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

  15. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Directory of Open Access Journals (Sweden)

    H. Kouyoumdjian

    2006-01-01

    Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

  16. Comparison of acute oxidative stress on rat lung induced by nano and fine-scale, soluble and insoluble metal oxide particles: NiO and TiO2.

    Science.gov (United States)

    Horie, Masanori; Fukui, Hiroko; Endoh, Shigehisa; Maru, Junko; Miyauchi, Arisa; Shichiri, Mototada; Fujita, Katsuhide; Niki, Etsuo; Hagihara, Yoshihisa; Yoshida, Yasukazu; Morimoto, Yasuo; Iwahashi, Hitoshi

    2012-06-01

    The aim of the present study is to understand the association between metal ion release from nickel oxide (NiO) nanoparticles and induction of oxidative stress in the lung. NiO nanoparticles have cytotoxic activity through nickel ion release and subsequent oxidative stress. However, the interaction of oxidative stress and nickel ion release in vivo is still unclear. In the present study, we examined the effect of metal ion release on oxidative stress induced by NiO nanoparticles. Additionally, nano and fine TiO(2) particles as insoluble particles were also examined. Rat lung was exposed to NiO and TiO(2) nanoparticles by intratracheal instillation. The NiO nanoparticles released Ni(2+) in dispersion. Bronchoalveolar lavage fluid (BALF) was collected at 1, 24, 72 h and 1 week after instillation. The lactate dehydrogenase (LDH) and HO-1 levels were elevated at 24 and 72 h after instillation in the animals exposed to the NiO nanoparticles. On the other hand, total hydroxyoctadecadienoic acid (tHODE), which is an oxidative product of linoleic acid, as well as SP-D and α-tochopherol levels were increased at 72 h and 1 week after instillation. Fine NiO particles, and nano and fine TiO(2) particles did not show lung injury or oxidative stress from 1 h to 1 week after instillation. These results suggest that Ni(2+) release is involved in the induction of oxidative stress by NiO nanoparticles in the lung. Ni(2+) release from NiO nanoparticles is an important factor inoxidative stress-related toxicity, not only in vitro but also in vivo.

  17. Nanomedical science and laser-driven particle acceleration: promising approaches in the prethermal regime

    Science.gov (United States)

    Gauduel, Y. A.

    2017-05-01

    A major challenge of spatio-temporal radiation biomedicine concerns the understanding of biophysical events triggered by an initial energy deposition inside confined ionization tracks. This contribution deals with an interdisciplinary approach that concerns cutting-edge advances in real-time radiation events, considering the potentialities of innovating strategies based on ultrafast laser science, from femtosecond photon sources to advanced techniques of ultrafast TW laser-plasma accelerator. Recent advances of powerful TW laser sources ( 1019 W cm-2) and laser-plasma interactions providing ultra-short relativistic particle beams in the energy domain 5-200 MeV open promising opportunities for the development of high energy radiation femtochemistry (HERF) in the prethermal regime of secondary low-energy electrons and for the real-time imaging of radiation-induced biomolecular alterations at the nanoscopic scale. New developments would permit to correlate early radiation events triggered by ultrashort radiation sources with a molecular approach of Relative Biological Effectiveness (RBE). These emerging research developments are crucial to understand simultaneously, at the sub-picosecond and nanometric scales, the early consequences of ultra-short-pulsed radiation on biomolecular environments or integrated biological entities. This innovating approach would be applied to biomedical relevant concepts such as the emerging domain of real-time nanodosimetry for targeted pro-drug activation and pulsed radio-chimiotherapy of cancers.

  18. Anne Fine

    Directory of Open Access Journals (Sweden)

    Philip Gaydon

    2015-04-01

    Full Text Available An interview with Anne Fine with an introduction and aside on the role of children’s literature in our lives and development, and our adult perceptions of the suitability of childhood reading material.Since graduating from Warwick in 1968 with a BA in Politics and History, Anne Fine has written over fifty books for children and eight for adults, won the Carnegie Medal twice (for Goggle-Eyes in 1989 and Flour Babies in 1992, been a highly commended runner-up three times (for Bill’s New Frock in 1989, The Tulip Touch in 1996, and Up on Cloud Nine in 2002, been shortlisted for the Hans Christian Andersen Award (the highest recognition available to a writer or illustrator of children’s books, 1998, undertaken the positon of Children’s Laureate (2001-2003, and been awarded an OBE for her services to literature (2003. Warwick presented Fine with an Honorary Doctorate in 2005.Philip Gaydon’s interview with Anne Fine was recorded as part of the ‘Voices of the University’ oral history project, co-ordinated by Warwick’s Institute of Advanced Study.

  19. Feynman Diagrams as Metaphors: Borrowing the Particle Physicist's Imagery for Science Communication Purposes

    Science.gov (United States)

    Pascolini, A.; Pietroni, M.

    2002-01-01

    We report on an educational project in particle physics based on Feynman diagrams. By dropping the mathematical aspect of the method and keeping just the iconic one, it is possible to convey many different concepts from the world of elementary particles, such as antimatter, conservation laws, particle creation and destruction, real and virtual…

  20. Preparation of Ni-Cr overlay weld alloy with finely dispersed NbC particles from (Ni-Cr)/NbC composite powder. Fukugo funmatsu wo mochiita bisai NbC ryushi bunsan Ni-Cr nikumori gokin no sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, T.; Takatani, Y. (Hyogo Prefectural Inst. of Industrial Research, Hyogo (Japan)); Harada, Y.; Nagai, K. (Tocalo Co. Ltd., Kobe (Japan))

    1992-11-20

    In previous studies, Ni-Cr overlay alloy containing NbC particles, formed by the plasma powder welding process, was found to exhibit excellent wear and corrosion resistances. However, any overlay alloy with dispersed NbC particles having a diameter below a few micron, has not been yet obtained. In this study, a composite powder was prepared by compounding 40 vol.% of NbC powder having an average grain diameter of 1.3 [mu]m into Ni-50 mass% Cr alloy powder, and then mixing, granulating and sintering. Plasma powder weddings were carried out on a mild steel plate using this complex powder, and the effect of plasma arc current on melting of complex powder particles and dispersion behavior of NbC particles was studied by structure observation and X-ray diffractometry. As a result, it was clarified that by selecting the proper plasma arc current and controlling the heat input, uniform dispersion of fine NbC particles having a diameter of a few micron into the matrix was possible. 18 refs., 8 figs., 3 tabs.

  1. 锡石颗粒与氢气泡间的碰撞粘附行为%Collision and attachment behavior between fine cassiterite particles and H2 bubbles

    Institute of Scientific and Technical Information of China (English)

    任浏祎; 张一敏; 覃文庆; 包申旭; 王军

    2014-01-01

    Particle-bubble interaction during electro-flotation of cassiterite was investigated by determining the recovery of cassiterite and the collision mechanism of cassiterite particle and H2 bubble. Flotation tests at different conditions were conducted in a single bubble flotation cell. The recovery of cassiterite was found to be affected by cassiterite particle and bubble size. A matching range, in which the best recovery can be obtained, was found between particle and bubble size. Collision, attachment, and detachment of the particle-bubble were observed and captured by a high-speed camera. Particle-bubble collision and attachment were analyzed with the use of particle-bubble interaction theory to obtain the experimental results. An attachment model was introduced and verified through the photos captured by the high-speed camera. A bridge role was observed between the bubbles and particles. Particle-bubble interaction was found to be affected by bubble size and particle size, which significantly influenced not only the collision and attachment behavior of the particles and bubbles but also the flotation recovery of fine cassiterite particles.%运用回收率和细粒锡石-气泡间的碰撞机制研究颗粒-气泡间的相互作用。用单泡浮选管进行浮选实验,考查不同条件下细粒锡石的浮选行为。结果表明,浮选回收率受颗粒和气泡尺寸的影响很大,在浮选回收率最高时,颗粒和气泡间存在一个最佳的匹配范围。运用高速摄影仪观察并捕捉颗粒-气泡间的碰撞、粘附、脱附过程,在已有理论的基础上,分析颗粒-气泡间的碰撞-粘附现象并解释浮选实验结果,通过捕捉图片证明颗粒-气泡间的粘附模型,发现颗粒-气泡间的桥连作用。锡石、气泡尺寸的大小影响锡石-气泡间的相互作用,这不仅影响锡石-气泡间的碰撞粘附行为,并最终影响细粒锡石的浮选回收率。

  2. High time-resolved elemental components in fine and coarse particles in the Pearl River Delta region of Southern China: Dynamic variations and effects of meteorology.

    Science.gov (United States)

    Zhou, Shengzhen; Davy, Perry K; Wang, Xuemei; Cohen, Jason Blake; Liang, Jiaquan; Huang, Minjuan; Fan, Qi; Chen, Weihua; Chang, Ming; Ancelet, Travis; Trompetter, William J

    2016-12-01

    Hourly-resolved PM2.5 and PM10-2.5 samples were collected in the industrial city Foshan in the Pearl River Delta region, China. The samples were subsequently analyzed for elemental components and black carbon (BC). A key purpose of the study was to understand the composition of particulate matter (PM) at high-time resolution in a polluted urban atmosphere to identify key components contributing to extreme PM concentration events and examine the diurnal chemical concentration patterns for air quality management purposes. It was found that BC and S concentrations dominated in the fine mode, while elements with mostly crustal and oceanic origins such as Si, Ca, Al and Cl were found in the coarse size fraction. Most of the elements showed strong diurnal variations. S did not show clear diurnal variations, suggesting regional rather than local origin. Based on empirical orthogonal functions (EOF) method, 3 forcing factors were identified contributing to the extreme events of PM2.5 and selected elements, i.e., urban direct emissions, wet deposition and a combination of coarse mode sources. Conditional probability functions (CPF) were performed using wind profiles and elemental concentrations. The CPF results showed that BC and elemental Cl, K, Fe, Cu and Zn in the fine mode were mostly from the northwest, indicating that industrial emissions and combustion were the main sources. For elements in the coarse mode, Si, Al, K, Ca, Fe and Ti showed similar patterns, suggesting same sources such as local soil dust/construction activities. Coarse elemental Cl was mostly from the south and southeast, implying the influence of marine aerosol sources. For other trace elements, we found vanadium (V) in fine PM was mainly from the sources located to the southeast of the measuring site. Combined with CPF results of S and V in fine PM, we concluded shipping emissions were likely an important elemental emission source.

  3. Waste Utilization as Fine Coconut Fiber for Core and Wood Waste Bayur to The Face Layer of The Physical and Mechanical Properties of Particle Board Produced

    Directory of Open Access Journals (Sweden)

    Sahadi Didi Ismanto

    2014-01-01

    Full Text Available This study aims to determine the effect of wood particle bayur comparison to the outer layer of coconut husk particle board smooth the physical and mechanical properties of the resulting particle board . The design used was completely randomized design ( CRD with 5 treatments with 3 replications for each treatment used is the use of wood particles bayur as the outer layer of particle board and refined coconut fiber as a core that is 80 % : 20 % , 70 % : 30 % , 60 % : 40 % , 50 % : 50 % , 40 % : 60 % observational data physical and mechanical properties were analyzed using analysis of variance if significantly different then performed with a further test of Duncan's New Multiple Range Test ( DMNRT at the 5% significance level . Observations made on the physical properties of particle board include : water content , water absorption and thickness expansion. The mechanical properties of particle board : strength broken , the pressure parallel and bonding strength. Based on the research that has been carried out showed that the utilization of wood waste bayur as the outer layer of particle board on a percentage varying significantly different effect on strength broken , water content , water absorption , expansion of thick , strength pressure bonding parallel to the internal surface . The results show the percentage of particle board with wood bayur with delicate coconut husk ( 40:60 is the best board with a water content of 6.11% , water absorption 20.56 % 10.93 % thicker expansion, density of 0.84 % , bonding strength of 56.90 kg / cm 2 pressure and parallel fiber determination 146.65 kg /cm 2.

  4. An evaluation of the particle physics Masterclass as a context for student learning about the nature of science

    Science.gov (United States)

    Wadness, Michael J.

    This dissertation addresses the research question: To what extent do secondary school science students attending the U.S. Particle Physics Masterclass change their view of the nature of science (NOS)? The U.S. Particle Physics Masterclass is a physics outreach program run by QuarkNet, a national organization of secondary school physics teachers and particle physicists partially funded by the National Science Foundation and the Department of Energy. The Masterclass is a one-day event in which high school physics students gather at a local research institution to learn about particle physics and the scientific enterprise. Student activities include introductory lectures in particle physics, laboratory tours, data analysis, and the discussion of their findings in a conference-like atmosphere. Although the Masterclass has been previously evaluated for students' learning of particle physics content, it was unknown if students' understanding of NOS changed after attending the Masterclass. This research concerns the problem of science literacy, specifically students' understanding of the nature of science (NOS). Previous research suggests that students do not implicitly acquire a sufficient understanding of NOS through the instruction of science content or through inquiry investigations. The literature suggests that sufficient understanding of NOS will only be successful if it is explicitly taught within a context. Unfortunately, research also suggests that many teachers do not include explicit instruction of NOS due various reasons that include a lack of time, understanding, and resources. Therefore, a need presents itself for curriculum extension programs in which explicit learning of NOS may occur. Due to the Masterclass explicitly including NOS within its introductory presentations, it was hypothesized that the remaining Masterclass activities may provide a context for student learning of NOS. The design of this study was a mixed methodology utilizing repeated

  5. Experimental study on promotion of coal combustion fine particles acoustic agglomeration removal by using wetting agents%润湿剂促进燃煤细颗粒声波团聚脱除的实验研究

    Institute of Scientific and Technical Information of China (English)

    颜金培; 陈立奇; 杨林军

    2014-01-01

    在声波团聚室中研究了润湿剂液滴与细颗粒碰撞团聚脱除特性,提出了一种利用润湿剂促进细颗粒在声波场中捕集的新方法。结果表明,不同润湿剂溶液对细颗粒在声波场中的团聚脱除效果存在较大差异,采用 JFC 和 FS-310润湿剂溶液时,细颗粒分级脱除效率与采用水时的分级脱除效率相近。而 SDS 和 Silanol w22溶液,则可有效提高细颗粒在各粒径段的分级脱除效率。细颗粒在声波场中的脱除效率与润湿剂润湿性能具有很好的相关性,随润湿剂对细颗粒相对接触角增大而降低,在声压级为150 dB 时,相对接触角由83°降低到0°,细颗粒脱除效率提高了18%,在无声场作用下,脱除效率仅提高了5%。细颗粒脱除效率随声压级的增大而提高,在低声压级条件下,添加润湿剂可有效提高细颗粒脱除效率,声压级在130 dB时,添加 SDS 溶液液滴后细颗粒脱除效率比声场单独作用时的脱除效率提高了25%。表明添加润湿剂可有效提高细颗粒在声波场中的团聚脱除效率,实现在低声压级条件下,获得高的细颗粒脱除效率。%The characteristics of agglomeration removal between wetting agent droplets and fine particles wereinvestigated in an acoustic agglomeration chamber. A novel technique using wetting agents to promote the fine particle capture by acoustic agglomeration was presented. The experimental results show that the type of wetting agent has a significant effect on the acoustic agglomeration of fine particles. The particle stage removal efficiencies using JFC and FS-310 are similar to that using plain water droplets, but the removal efficiencies bySDS and Silanol w 22 are much higher than that using water droplets. Fine particle removal efficiency in the acoustic field correlates well with the wettability of wetting agents, which decreases with increasing the relativecontact angle of wetting agents

  6. Charged particle spectra measured during the transit to Mars with the Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    Science.gov (United States)

    Ehresmann, Bent; Hassler, Donald M.; Zeitlin, Cary; Guo, Jingnan; Köhler, Jan; Wimmer-Schweingruber, Robert F.; Appel, Jan K.; Brinza, David E.; Rafkin, Scot C. R.; Böttcher, Stephan I.; Burmeister, Sönke; Lohf, Henning; Martin, Cesar; Böhm, Eckart; Matthiä, Daniel; Reitz, Günther

    2016-08-01

    The Mars Science Laboratory (MSL) started its 253-day cruise to Mars on November 26, 2011. During cruise the Radiation Assessment Detector (RAD), situated on board the Curiosity rover, conducted measurements of the energetic-particle radiation environment inside the spacecraft. This environment consists mainly of galactic cosmic rays (GCRs), as well as secondary particles created by interactions of these GCRs with the spacecraft. The RAD measurements can serve as a proxy for the radiation environment a human crew would encounter during a transit to Mars, for a given part of the solar cycle, assuming that a crewed vehicle would have comparable shielding. The measurements of radiological quantities made by RAD are important in themselves, and, the same data set allow for detailed analysis of GCR-induced particle spectra inside the spacecraft. This provides important inputs for the evaluation of current transport models used to model the free-space (and spacecraft) radiation environment for different spacecraft shielding and different times in the solar cycle. Changes in these conditions can lead to significantly different radiation fields and, thus, potential health risks, emphasizing the need for validated transport codes. Here, we present the first measurements of charged particle fluxes inside a spacecraft during the transit from Earth to Mars. Using data obtained during the last two month of the cruise to Mars (June 11-July 14, 2012), we have derived detailed energy spectra for low-Z particles stopping in the instrument's detectors, as well as integral fluxes for penetrating particles with higher energies. Furthermore, we analyze the temporal changes in measured proton fluxes during quiet solar periods (i.e., when no solar energetic particle events occurred) over the duration of the transit (December 9, 2011-July 14, 2012) and correlate them with changing heliospheric conditions.

  7. Charged particle spectra measured during the transit to Mars with the Mars Science Laboratory Radiation Assessment Detector (MSL/RAD).

    Science.gov (United States)

    Ehresmann, Bent; Hassler, Donald M; Zeitlin, Cary; Guo, Jingnan; Köhler, Jan; Wimmer-Schweingruber, Robert F; Appel, Jan K; Brinza, David E; Rafkin, Scot C R; Böttcher, Stephan I; Burmeister, Sönke; Lohf, Henning; Martin, Cesar; Böhm, Eckart; Matthiä, Daniel; Reitz, Günther

    2016-08-01

    The Mars Science Laboratory (MSL) started its 253-day cruise to Mars on November 26, 2011. During cruise the Radiation Assessment Detector (RAD), situated on board the Curiosity rover, conducted measurements of the energetic-particle radiation environment inside the spacecraft. This environment consists mainly of galactic cosmic rays (GCRs), as well as secondary particles created by interactions of these GCRs with the spacecraft. The RAD measurements can serve as a proxy for the radiation environment a human crew would encounter during a transit to Mars, for a given part of the solar cycle, assuming that a crewed vehicle would have comparable shielding. The measurements of radiological quantities made by RAD are important in themselves, and, the same data set allow for detailed analysis of GCR-induced particle spectra inside the spacecraft. This provides important inputs for the evaluation of current transport models used to model the free-space (and spacecraft) radiation environment for different spacecraft shielding and different times in the solar cycle. Changes in these conditions can lead to significantly different radiation fields and, thus, potential health risks, emphasizing the need for validated transport codes. Here, we present the first measurements of charged particle fluxes inside a spacecraft during the transit from Earth to Mars. Using data obtained during the last two month of the cruise to Mars (June 11-July 14, 2012), we have derived detailed energy spectra for low-Z particles stopping in the instrument's detectors, as well as integral fluxes for penetrating particles with higher energies. Furthermore, we analyze the temporal changes in measured proton fluxes during quiet solar periods (i.e., when no solar energetic particle events occurred) over the duration of the transit (December 9, 2011-July 14, 2012) and correlate them with changing heliospheric conditions.

  8. Indirect estimation of absorption properties for fine aerosol particles using AATSR observations: a case study of wildfires in Russia in 2010

    Science.gov (United States)

    Rodriguez, E.; Kolmonen, P.; Virtanen, T. H.; Sogacheva, L.; Sundstrom, A.-M.; de Leeuw, G.

    2015-08-01

    The Advanced Along-Track Scanning Radiometer (AATSR) on board the ENVISAT satellite is used to study aerosol properties. The retrieval of aerosol properties from satellite data is based on the optimized fit of simulated and measured reflectances at the top of the atmosphere (TOA). The simulations are made using a radiative transfer model with a variety of representative aerosol properties. The retrieval process utilizes a combination of four aerosol components, each of which is defined by their (lognormal) size distribution and a complex refractive index: a weakly and a strongly absorbing fine-mode component, coarse mode sea salt aerosol and coarse mode desert dust aerosol). These components are externally mixed to provide the aerosol model which in turn is used to calculate the aerosol optical depth (AOD). In the AATSR aerosol retrieval algorithm, the mixing of these components is decided by minimizing the error function given by the sum of the differences between measured and calculated path radiances at 3-4 wavelengths, where the path radiances are varied by varying the aerosol component mixing ratios. The continuous variation of the fine-mode components allows for the continuous variation of the fine-mode aerosol absorption. Assuming that the correct aerosol model (i.e. the correct mixing fractions of the four components) is selected during the retrieval process, also other aerosol properties could be computed such as the single scattering albedo (SSA). Implications of this assumption regarding the ratio of the weakly/strongly absorbing fine-mode fraction are investigated in this paper by evaluating the validity of the SSA thus obtained. The SSA is indirectly estimated for aerosol plumes with moderate-to-high AOD resulting from wildfires in Russia in the summer of 2010. Together with the AOD, the SSA provides the aerosol absorbing optical depth (AAOD). The results are compared with AERONET data, i.e. AOD level 2.0 and SSA and AAOD inversion products. The RMSE

  9. From art to science: the functional damage due to thumb osteoarthritis finely described by Velazquez 300 years before its clinical description.

    Science.gov (United States)

    Villafañe, J H; Cantero-Tellez, R; Negrini, S; Berjano, P

    2017-09-21

    Velazquez showed to know the entity of thumb osteoarthritis by finely describing it in one of his paintings. The concepts of anatomical damage, loss of strenght, and functional impairment are transmitted to the observer.

  10. Synthesis and photocatalytic application of α-Fe2O3/ZnO fine particles prepared by two-step chemical method

    Directory of Open Access Journals (Sweden)

    Patij Shah

    2013-06-01

    Full Text Available Composite iron oxide-Zinc oxide (α-Fe2O3/ZnO was synthesized by two-step method: in the first one step uniform α-Fe2O3 particles were prepared through a hydrolysis process of ferric chloride at 80 °C. In the second step, the ZnO particles were included in the α-Fe2O3 particles by a zinc acetate [Zn(Ac2·2H2O] assisted hydrothermal method at low temperature (90°C±C. The α-Fe2O3 and ZnO phases were identified by XRD, energy dispersive X-ray analysis (EDX. The photoreactivities of α-Fe2O3/ZnO nanoparticles under UV irradiation were quantified by the degradation of formaldehyde.

  11. 不同絮凝剂对微细粒赤铁矿、石英的絮凝行为研究%Study on flocculation behaviors &mechanism of different flocculating agents of fine hematite and quartz particle

    Institute of Scientific and Technical Information of China (English)

    张晋霞; 牛福生

    2016-01-01

    通过单矿物沉降实验,考查了不同絮凝剂的种类、搅拌强度对赤铁矿、石英的絮凝行为影响规律.结果表明,4种絮凝剂剂对赤铁矿絮凝效果由强至弱的顺序为:苛化玉米淀粉>羧甲基纤维素钠>十二烷基磺酸钠>聚丙烯酰胺.在一定范围内增强搅拌强度有利于微细粒颗粒的絮凝,但超过某一临界值后絮凝效果变差.Zeta电位测定表明,随着淀粉用量的增加,赤铁矿的电位逐渐增大,降低了颗粒间的静电斥力,促进淀粉在赤铁矿表面的吸附.%The influences of flocculant types ,stirring intensity on flocculation behaviors of fine hematite and quartz particle were studied by sedimentation experiments .The results shows that four kinds of flocculants in the same concentration ,the order of fine hematite was corn starch > sodium carboxymethyl cellulose > sodium dodecylsulphate > polyacrylamide .The hematite and quartz particles can be better flocculated with the increase of stirring speed in a range ,but the flocculation effect becomes worse when the stirring speed exceed a critical value .The analyse of the zeta potentials show that starch can be adsorbed onto hematite minerals which increased the zeta potential of the hematite and lowed electrostatic repulsion of between the particles .

  12. Which fine-tuning arguments are fine?

    CERN Document Server

    Grinbaum, Alexei

    2009-01-01

    The argument from naturalness is widely employed in contemporary quantum field theory. Essentially a formalized aesthetic criterion, it received a meaning in the debate on the Higgs mechanism, which goes beyond aesthetics. We follow the history of technical definitions of fine tuning at the scale of electroweak symmetry breaking. It is argued that they give rise to a special interpretation of probability, which we call Gedankenfrequency. By extension of its original meaning, the argument from naturalness is used to compare different models beyond the Standard Model. We show that in this case naturalness cannot be defined objectively. Rather, it functions as socio-historical heuristics in particle physics and it contributes to the advent of a probabilistic version of Popper's falsificationism.

  13. Photographic science advances in nano-particles J-aggregates dye sensitization and organic devices

    CERN Document Server

    Tani, Tadaaki

    2011-01-01

    This book provides a guide to modern developments in photographic science and their possible applications to new and exciting areas, including nano-technology, solar cells, and organic semiconductors.

  14. Small Particles in Cirrus (SPartICus) and Storm Peak Lab Validation Experiment (StormVEx) Science Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Mace, Gerald [Univ. of Utah, Salt Lake City, UT (United States)

    2016-10-28

    The Small Particles in Cirrus (SPartICus) campaign took place from January through June, 2011 and the Storm Peak Lab Cloud Property Validation Experiment (StormVEx) took place from November, 2011 through April, 2012. The PI of this project, Dr. Gerald Mace, had the privilege to be the lead on both of these campaigns. The essence of the project that we report on here was to conduct preliminary work that was necessary to bring the field data sets to a point where they could be used for their intended science purposes

  15. Production of De-asphalted Oil and Fine Asphalt Particles by Supercritical Extraction%超临界流体萃取制备脱沥青油与沥青微粒

    Institute of Scientific and Technical Information of China (English)

    赵锁奇; 许志明; 王仁安

    2003-01-01

    A continuous three-stage supercritical fluid extraction (SFE) process with a capacity of 1.0 kg·h-1 was setup to extract petroleum residue by pentane to obtain more oil for further upgrading. A discharging system integrated to the bottom of the extractor was used to recover solvent as gas while asphalt was obtained as fine particles. The influence of operating conditions on the yield and quality of extracts, i.e., deasphalted oil (DAO) and resin, was studied in the range of temperature 150-220℃, pressure of 4.0-6.0 MPa and the mass ratio of solvent to oil feed (S/O) 2.5-5.0. The particle size distribution, apparent forms and the packing density, which vary with operating pressure, were measured. The particle structures were observed by SEM as well. With the modification to conventional processes, furnace can be eliminated for solvent recovery from asphalt phase, so as to reduce energy consumption.

  16. Fluidized-bed gasification of biomass: Conversion of fine carabon particles in the freeboard; Biomassevergasung in der Wirbelschicht: Umsatz von feinen Kohlenstoffpartikeln im Freeboard

    Energy Technology Data Exchange (ETDEWEB)

    Miccio, F. [Ist. Ricerche sulla Combustione-CNR, Napoli (Italy); Moersch, O.; Spliethoff, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    1998-09-01

    The conversion of carbon particles in gasification processes was investigated in a fluidized-bed reactor of the Institute of Chemical Engineering and Steam Boiler Technology of Stuttgart University. This reactor is heated electrically to process temperature, and freeboard coal particles can be sampled using an isokinetic probe. The fuel used in the experiments consisted of beech wood chips. The temperature and air rating, i.e. the main parameters of the process, were varied in order to investigate their influence on product gas quality and carbon conversion. The conversion rate is influenced to a significant extent by grain disintegration and discharge of carbon particles. In gasification conditions, a further conversion process takes place in the freeboard. (orig.) [Deutsch] In dieser Arbeit wird die Umsetzung von Kohlenstoffpartikeln unter Vergasungsbedingungen untersucht. Die Versuche wurden an einem Wirbelschichtreaktor des Instituts fuer Verfahrenstechnik und Dampfkesselwesen der Universitaet Stuttgart durchgefuehrt. Dieser Reaktor wird elektrisch auf Prozesstemperatur beheizt. Mit Hilfe einer isokinetischen Sonde koennen Proben von Kohlenstoffpartikeln im Freeboard genommen werden. Als Brennstoff wurden zerkleinerte Buchenholz-Hackschnitzel eingesetzt. Variiert wurden als Hauptparameter des Prozesses Temperatur und Luftzahl. Untersucht wurde der Einfluss dieser Parameter auf die Qualitaet des Produktgases und die Umsetzung des Kohlenstoffes. Kornzersetzungs- und Austragsvorgaenge von Kohlenstoffpartikeln spielen eine wichtige Rolle fuer den Kohlenstoffumsatz. Unter Vergasungsbedingungen findet im Freeboard eine weitere Umsetzung der Partikel statt. (orig.)

  17. Single particle counting diagnostic system for measuring fine particulates at high number densities in research and industrial applications. Final report summarizing instrument development, validation and operating instructions

    Energy Technology Data Exchange (ETDEWEB)

    Holve, D.J.

    1983-10-01

    Optical methods for particle size distribution measurements in practical high temperature environments have achieved feasibility and offer significant advantages over conventional sampling methods. The present report describes a mobile electro-optical system which has been designed for general use in a wide range of research and industrial environments. Specific features of this system include a method of providing in situ alignment and incorporation of an extinction measurement for application to optically thick aerosol flows. The instrument has demonstrated capability for measuring individual particles in the size range 0.25 to 100 microns at number densities up to 10/sup 12//m/sup 3/. In addition to demonstration of the system's wide dynamic range, we show the utility of the in situ alignment method in hot (1100 K) turbulent flows where beam steering can be a problem. As an example of the instrument's application, number and mass frequency distribution measurements of flyash and pulverized coal obtained in an atmospheric combustion exhaust simulator show that the raw pulverized coal contains large numbers of submicron particles similar to the flyash formed after combustion.

  18. Fine Particle Size Moving and It′s Effective on Debris Flow Initiation%细颗粒迁移在泥石流形成过程中的作用

    Institute of Scientific and Technical Information of China (English)

    庄建琦; 崔鹏; 胡凯衡; 陈晓清

    2015-01-01

    针对松散物质异常丰富孕灾环境条件下泥石流的形成过程和泥沙来源,设计了人工降雨条件下泥石流形成试验,主要获得以下结果:1.震后孕灾环境条件下泥石流的形成首先需要细颗粒的起动,然后夹杂大颗粒运动,径流量快速增加,并伴随着沟道堵塞-溃决现象,形成阵性泥石流;此后随着细颗粒的迁移,沟道粗化现象严重,泥石流现象逐渐消失。2.坡面首先对降雨开始响应,发生崩塌形成堰塞体,对沟道侵蚀产生较大影响,并伴随着坝体松散物质溃决向下游迁移。3.泥石流的泥沙主要来源于沟道中下游,其次是沟道中上游和源头坡面,三处的泥沙来源占到70%以上。4.土体对降雨的响应明显,孔隙水压力和含水量在不同时间段和不同部位变化曲线具有明显差异,并出现一定的波动特征,其不仅受到降雨的影响,同时对土体细颗粒含量和土体结构也有明显响应。5.细颗粒在泥石流的形成过程中扮演者非常重要的角色,其位移和汇集均对流域地形的演化和泥石流的形成产生影响。在泥石流形成预报时,应考虑土体细颗粒含量,不同的细颗粒含量其泥石流起动时临界含水量和孔隙水压力差异较大。%Designing the experiment on debris flow formation process at artificial rainfall at the conditions of the loose material unusually rich for studying the debris flow formation process. The main results showed:1. The fine particles moving first for the initiation of debris flow,and then mixed with the large particle and runoff increased sharply,along with channel block-outburst phenomenon;the debris flow phenomena gradually disappeared with the fine particles migration off and the channel rough serious. 2. The slop failure and moving at the rainstorm,the fail-ure material deposited in channel and formed the dams which effect the erosion and deposits of the channel

  19. Discrete-element modelling and smoothed particle hydrodynamics: potential in the environmental sciences.

    Science.gov (United States)

    Cleary, Paul W; Prakash, Mahesh

    2004-09-15

    Particle-based simulation methods, such as the discrete-element method and smoothed particle hydrodynamics, have specific advantages in modelling complex three-dimensional (3D) environmental fluid and particulate flows. The theory of both these methods and their relative advantages compared with traditional methods will be discussed. Examples of 3D flows on realistic topography illustrate the environmental application of these methods. These include the flooding of a river valley as a result of a dam collapse, coastal inundation by a tsunami, volcanic lava flow and landslides. Issues related to validation and quality data availability are also discussed.

  20. Influence of fine sediment on the fluidity of debris flows

    OpenAIRE

    HOTTA, Norifumi; Kaneko, Takahiro; Iwata, Tomoyuki; Nishimoto, Haruo

    2013-01-01

    Debris flows include a great diversity of grain sizes with inherent features such as inverse grading, particle size segregation, and liquefaction of fine sediment. The liquefaction of fine sediment affects the fluidity of debris flows, although the behavior and influence of fine sediment in debris flows have not been examined sufficiently. This study used flume tests to detect the effect of fine sediment on the fluidity of laboratory debris flows consisting of particles with various diameters...

  1. A new kind of Big Science Smashing particles and counting birds

    CERN Multimedia

    Hirsh, Aaron

    2009-01-01

    Next summer, the Large Hadron Collider, Europe's $9 billion investment in particle physics, will take a handful of ions, hurt them through 17 miles of circular tunnel and smash them together so hard they will shatter into the finest atomic shards anyone has ever observed. (1 page)

  2. Science and engineering of nanodiamond particle surfaces for biological applications (Review).

    Science.gov (United States)

    Shenderova, Olga A; McGuire, Gary E

    2015-09-05

    Diamond has outstanding bulk properties such as super hardness, chemical inertness, biocompatibility, luminescence, to name just a few. In the nanoworld, in order to exploit these outstanding bulk properties, the surfaces of nanodiamond (ND) particles must be accordingly engineered for specific applications. Modification of functional groups on the ND's surface and the corresponding electrostatic properties determine their colloidal stability in solvents, formation of photonic crystals, controlled adsorption and release of cargo molecules, conjugation with biomolecules and polymers, and cellular uptake. The optical activity of the luminescent color centers in NDs depends on their proximity to the ND's surface and surface termination. In order to engineer the ND surface, a fundamental understanding of the specific structural features and sp(3)-sp(2) phase transformations on the surface of ND particles is required. In the case of ND particles produced by detonation of carbon containing explosives (detonation ND), it should also be taken into account that its structure depends on the synthesis parameters and subsequent processing. Thus, for development of a strategy of surface modification of detonation ND, it is imperative to know details of its production. In this review, the authors discuss ND particles structure, strategies for surface modification, electrokinetic properties of NDs in suspensions, and conclude with a brief overview of the relevant bioapplications.

  3. The Effects of Toxic Particles in Human Lung Cells - Research Area 8. Life Sciences

    Science.gov (United States)

    2016-01-05

    over 300 commercial products including sunscreen, stain- resistant clothing, tires, refrigerators, washing machines and sports equipment. The military is...prompted the use of other metal alloys comprised of nickel, cobalt and tungsten. Cobalt and nickel exhibit strong corrosion and erosion resistance ...achieved by passing the prescreened (ឝ um) particles through successive filtration steps using vacuum and Anatop filters. After several such repeats

  4. In-depth compositional analysis of water-soluble and -insoluble organic substances in fine (PM2.5) airborne particles using ultra-high-resolution 15T FT-ICR MS and GC×GC-TOFMS.

    Science.gov (United States)

    Choi, Jung Hoon; Ryu, Jijeong; Jeon, Sodam; Seo, Jungju; Yang, Yung-Hun; Pack, Seung Pil; Choung, Sungwook; Jang, Kyoung-Soon

    2017-03-05

    Airborne particulate matter consisting of ionic species, salts, heavy metals and carbonaceous material is one of the most serious environmental pollutants owing to its impacts on the environment and human health. Although elemental and organic carbon compounds are known to be major components of aerosols, information on the elemental composition of particulate matter remains limited because of the broad range of compounds involved and the limits of analytical instruments. In this study, we investigated water-soluble and -insoluble organic compounds in fine (PM2.5) airborne particles collected during winter in Korea to better understand the elemental compositions and distributions of these compounds. To collect ultra-high-resolution mass profiles, we analyzed water-soluble and -insoluble organic compounds, extracted with water and dichloromethane, respectively, using an ultra-high-resolution 15 T Fourier transform ion cyclotron resonance (15T FT-ICR) mass spectrometer in positive ion mode (via both electrospray ionization [ESI] and atmospheric pressure photoionization [APPI] for water-extracts and via APPI for dichloromethane-extracts). In conjunction with the FT-ICR mass spectrometry (MS) data, subsequent two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) data were used to identify potentially hazardous organic components, such as polycyclic aromatic hydrocarbons. This analysis provided information on the sources of ambient particles collected during winter season and partial evidence of contributions to the acidity of organic content in PM2.5 particles. The compositional and structural features of water-soluble and -insoluble organic compounds from PM2.5 particles are important for understanding the potential impacts of aerosol-carried organic substances on human health and global ecosystems in future toxicological studies.

  5. Fine particle exposure of prescribed fire workers in the Southeastern United States and a comparison of several particulate matter sampling methods.

    Energy Technology Data Exchange (ETDEWEB)

    Yanosky, Jeffrey, David

    2001-07-01

    Personal exposure concentrations of particles with aerodynamic diameter <2.5 μm (PM2.5) of prescribed fire workers were measured at two locations in the southeastern United States. Non-impacted ambient concentrations were measured as an estimate of background concentrations during burn activities. Four sampling method comparison studies were designed and performed to compare the FRM with 1) other gravimetric PM2.5 sampling methods in ambient air, 2) optical PM2.5 sampling methods in indoor air, 3) an optical sampling method (Grimm) for particles with aerodynamic diameter <10 μm (PM10) in ambient air, and 4) a gravimetric PM2.5 sampling method downwind of prescribed fires. The gravimetric PM2.5 sampling methods agreed well in ambient air (R2>0.96 for all) except for the MiniVol, the optical PM2.5 sampling methods agree less well in indoor air,(R2>0.592), the Grimm optical PM10 method agrees well in ambient air(R2>0.944 for all), and the personal method agrees well (n=9, R2=0.994) downwind of prescribed fires.

  6. Fine particle exposure of prescribed fire workers in the Southeastern United States and a comparison of several particulate matter sampling methods.

    Energy Technology Data Exchange (ETDEWEB)

    Yanosky, Jeffrey, David

    2001-07-01

    Personal exposure concentrations of particles with aerodynamic diameter <2.5 μm (PM2.5) of prescribed fire workers were measured at two locations in the southeastern United States. Non-impacted ambient concentrations were measured as an estimate of background concentrations during burn activities. Four sampling method comparison studies were designed and performed to compare the FRM with 1) other gravimetric PM2.5 sampling methods in ambient air, 2) optical PM2.5 sampling methods in indoor air, 3) an optical sampling method (Grimm) for particles with aerodynamic diameter <10 μm (PM10) in ambient air, and 4) a gravimetric PM2.5 sampling method downwind of prescribed fires. The gravimetric PM2.5 sampling methods agreed well in ambient air (R2>0.96 for all) except for the MiniVol, the optical PM2.5 sampling methods agree less well in indoor air,(R2>0.592), the Grimm optical PM10 method agrees well in ambient air(R2>0.944 for all), and the personal method agrees well (n=9, R2=0.994) downwind of prescribed fires.

  7. Raman microspectroscopy of exhaled breath condensate and urine in workers exposed to fine and nano TiO2 particles: a cross-sectional study.

    Science.gov (United States)

    Pelclova, Daniela; Barosova, Hana; Kukutschova, Jana; Zdimal, Vladimir; Navratil, Tomas; Fenclova, Zdenka; Vlckova, Stepanka; Schwarz, Jaroslav; Zikova, Nadezda; Kacer, Petr; Komarc, Martin; Belacek, Jaroslav; Zakharov, Sergey

    2015-07-14

    The health effects of engineered nanoparticles in humans are not well-understood; however experimental data support the theory of oxidative stress promoting fibrogenesis and carcinogenicity. The aim of this study was to detect TiO2 particles in exhaled breath condensate (EBC) and urine samples to ascertain their presence and potential persistence and excretion in urine.EBC and urine samples were collected from 20 workers exposed to TiO2 aerosol; among them, 16 had a higher risk level of exposure (production workers) and four had medium risk level (research workers); in addition to 20 controls. Titanium levels in EBC and urine were analysed using the inductively coupled plasma mass spectrometry (ICP-MS) method. A Raman microspectroscopic analysis was performed in EBC and urine to identify the phase composition of TiO2 particles observed. Aerosol exposure in the workplaces was measured using SMPS and APS spectrometers and P-TRAK and DustTRAK DRX monitors.The median concentration of TiO2 aerosol was 1.98 × 10(4) particles cm(-3), the interquartile range (IQR) was 1.50 × 10(4) - 3.01 × 10(4) particles cm(-3) and the median mass concentration was 0.65 mg m(-3) (IQR 0.46-.0.83 mg m(-3)); 70-82% of the particles were smaller than 100 nm in diameter. In any part of the plant, the median TiO2 air concentration did not exceed the national airborne exposure limit of 10 mg m(-3) for inert dust. Particles of rutile and/or anatase were found in the EBC of exposed workers in 8/20 (40%) of the pre-shift and 14/20 (70%) of the post-shift samples. In the urine of workers, TiO2 particles were detected in 2/20 post-shift urine samples only. The mean concentration of titanium in the EBC in production workers was 24.1 ± 1.8 µg/l. In the research workers the values were below the limit of quantitation; LOQ = 4.0 ± 0.2 µg/l), as well as in the controls. In the urine samples of all of the subjects, titanium was under the limit of detection (LOD = 1

  8. LABORATARY RESEARCH ON FINE PARTICLES MIGRATION OF HIGH CLAY DREDGER FILL IN CONSOLIDATION PROCESS%高黏性吹填土固结过程中细颗粒迁移规律研究

    Institute of Scientific and Technical Information of China (English)

    宋晶; 王清; 张鹏; 江小亮

    2012-01-01

    In the process of vacuum preloading consolidation, soft foundation is consolidated by powerful vacuum suction. A kind of soft clay has many fine particles that would be flowed to drain pipes with vacuum. The plastic pipes would be surrounded with clay. Then they would be formed with mud membrane. Through laboratory test, the course of drainage consolidation is simulated. It is aimed that the laws of particle migration can be resolved with the proposed approach. Test results confirm that the consolidation conditions affect the fine particle migration phenomenon. At the gravitational compaction consolidation stage, the fine particles are influenced by boundary conditions and seepage paths. However, at the pressure consolidation stage, the fine particles are influenced by the additional loading generated vertical pressure. Therefore, the tendency of particle migration is no more than weak. And The distribution of fine particles is changed from vertical gershgorim band to horizontal gershgorim band. Furthermore, the mass ratio of silt and clay is primary defined as aggregate clay ratio. It reflects the status of migration process. The "aggregate clay ratio" is considered as the indicator of migration. Data analysis results show that the indicator can effectively reflect the degree of consolidation. With the continuing process of consolidation drainage, the "aggregate clay ratio" is increasing gradually. It reflects indirectly the strength of high clay dredger fill. In the consolidation process, "aggregate clay ratio" is increased as the drainage velocity is changed lower.%软土地基在真空预压过程中,受强大的真空吸力作用,产生固结压密.其中一类软土黏粒含量较大,排水固结过程中产生细颗粒迁移现象,令土体固结的同时细颗粒也积聚在排水板四周,形成泥膜,造成后期排水通道堵塞,降低了固结效率.本研究采用室内试验模拟吹填土排水固结过程,监测颗粒分布情况,探讨细颗粒

  9. Fluidized reduction of oxides on fine metal powders without sintering

    Science.gov (United States)

    Hayashi, T.

    1985-01-01

    In the process of reducing extremely fine metal particles (av. particle size or = 1000 angstroms) covered with an oxide layer, the metal particles are fluidized by a gas flow contg. H, heated, and reduced. The method uniformly and easily reduces surface oxide layers of the extremely fine metal particles without causing sintering. The metal particles are useful for magnetic recording materials, conductive paste, powder metallurgy materials, chem. reagents, and catalysts.

  10. Chemical partitioning of fine particle-bound metals on haze-fog and non-haze-fog days in Nanjing, China and its contribution to human health risks

    Science.gov (United States)

    Li, Huiming; Wu, Hongfei; Wang, Qin'geng; Yang, Meng; Li, Fengying; Sun, Yixuan; Qian, Xin; Wang, Jinhua; Wang, Cheng

    2017-01-01

    Information on chemical partitioning and associated risk of airborne metals, particularly during a haze-fog episode, is limited. Fine particulate matter (PM2.5) was collected during a severe haze-fog event in winter and non-haze-fog periods in summer and fall from an urban region of a typical Chinese mega-city, Nanjing. The particulate-bound metals (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sr, Ti, V, and Zn) were chemically fractionated in a four-step sequential extraction procedure and human health risk was assessed. During the haze-fog episode, PM2.5 was extremely elevated with a mean concentration of 281 μg/m3 (range: 77-431 μg/m3), whereas the mean PM2.5 concentrations in summer and fall periods were 86 μg/m3 (range: 66-111 μg/m3) and 77 μg/m3 (range: 42-131 μg/m3), respectively. All elements had significantly higher concentrations and many metals exceeded relevant limits on haze-fog days. K, Na, Sr, Zn, Mo, Ca, Cd, Mg, Mn, Cu, Ba, Cr and As all showed relatively high proportions of the soluble and exchangeable fraction and strong bio-accessible potential. High temperature and humidity may increase the bio-accessible fraction of many airborne metals. The hazard index for potential toxic metals was 0.115, which was lower than the safe limit (1). However, the combined carcinogenic risk was 1.32 × 10- 6 for children and 5.29 × 10- 6 for adults, with both values being higher than the precautionary criterion (10- 6). Results of this study provide information for the behavior and risk mitigation of airborne metals.

  11. Assessment of the effect of population and diary sampling methods on estimation of school-age children exposure to fine particles.

    Science.gov (United States)

    Che, W W; Frey, H Christopher; Lau, Alexis K H

    2014-12-01

    Population and diary sampling methods are employed in exposure models to sample simulated individuals and their daily activity on each simulation day. Different sampling methods may lead to variations in estimated human exposure. In this study, two population sampling methods (stratified-random and random-random) and three diary sampling methods (random resampling, diversity and autocorrelation, and Markov-chain cluster [MCC]) are evaluated. Their impacts on estimated children's exposure to ambient fine particulate matter (PM2.5 ) are quantified via case studies for children in Wake County, NC for July 2002. The estimated mean daily average exposure is 12.9 μg/m(3) for simulated children using the stratified population sampling method, and 12.2 μg/m(3) using the random sampling method. These minor differences are caused by the random sampling among ages within census tracts. Among the three diary sampling methods, there are differences in the estimated number of individuals with multiple days of exposures exceeding a benchmark of concern of 25 μg/m(3) due to differences in how multiday longitudinal diaries are estimated. The MCC method is relatively more conservative. In case studies evaluated here, the MCC method led to 10% higher estimation of the number of individuals with repeated exposures exceeding the benchmark. The comparisons help to identify and contrast the capabilities of each method and to offer insight regarding implications of method choice. Exposure simulation results are robust to the two population sampling methods evaluated, and are sensitive to the choice of method for simulating longitudinal diaries, particularly when analyzing results for specific microenvironments or for exposures exceeding a benchmark of concern.

  12. Heterogeneities in inflammatory and cytotoxic responses of RAW 264.7 macrophage cell line to urban air coarse, fine, and ultrafine particles from six European sampling campaigns

    Energy Technology Data Exchange (ETDEWEB)

    Jalava, P.I.; Salonen, R.O.; Pennanen, A.S.; Sillanpaa, M.; Halinen, A.I.; Happo, M.S.; Hillamo, R.; Brunekreef, B.; Katsouyanni, K.; Sunyer, J.; Hirvonen, M.R. [National Public Health Institute, Kuopio (Finland). Dept. for Environmental Health

    2007-03-15

    We investigated the cytotoxic and inflammatory activities of size-segregated particulate samples (particulate matter, PM) from contrasting air pollution situations in Europe. Coarse (PM10-2.5), fine (PM2.5-0.2), and ultrafine (PM0.2) particulate samples were collected with a modified Harvard high-volume cascade impactor (HVCI). Mouse RAW 264.7 macrophages were exposed to the samples for 24 h. Selected inflammatory mediators, nitric oxide (NO) and cytokines (tumor necrosis factor alpha (TNF alpha), interleukin 6 (IL-6), macrophage inflammatory protein-2 (MIP-2)), were measured together with cytotoxicity (MTT test), and analysis of apoptosis and cell cycle (propidium iodide staining). The PM10-2.5 samples had a much higher inflammatory activity than the PM2.5-0.2 and PM0.2 samples, but the PM2.5-0.2 samples showed the largest differences in inflammatory activity, and the PM0.2 samples in cytotoxicity, between the sampling campaigns. The PM2.5-0.2 samples from traffic environments in springtime Barcelona and summertime Athens had the highest inflammatory activities, which may be related to the high photochemical activity in the atmosphere during the sampling campaigns. The PM0.2 sample from wintertime Prague with proven impacts from local coal and biomass combustion had very high cytotoxic and apoptotic activities and caused a distinct cell cycle arrest. Thus, particulate size, sources, and atmospheric transformation processes affect the toxicity profile of urban air particulate matter. These factors may explain some of the heterogeneity observed in particulate exposure-response relationships of human health effects in epidemiological studies.

  13. Vascular and lung function related to ultrafine and fine particles exposure assessed by personal and indoor monitoring: a cross-sectional study

    DEFF Research Database (Denmark)

    Olsen, Yulia; Karottki, Dorina Gabriela; Jensen, Ditte Marie

    2014-01-01

    -related effects. Methods: Associations between vascular and lung function, inflammation markers and exposure in terms of particle number concentration (PNC; d = 10-300 nm) were studied in a cross-sectional design with personal and home indoor monitoring in the Western Copenhagen Area, Denmark. During 48-h, PNC...... and PM2.5 were monitored in living rooms of 60 homes with 81 non-smoking subjects (30-75 years old), 59 of whom carried personal monitors both when at home and away from home. We measured lung function in terms of the FEV1/FVC ratio, microvascular function (MVF) and pulse amplitude by digital artery...... tonometry, blood pressure and biomarkers of inflammation including C-reactive protein, and leukocyte counts with subdivision in neutrophils, eosinophils, monocytes, and lymphocytes in blood. Results: PNC from personal and stationary home monitoring showed weak correlation (r = 0.15, p = 0.24). Personal UFP...

  14. Feasibility of using low-cost portable particle monitors for measurement of fine and coarse particulate matter in urban ambient air.

    Science.gov (United States)

    Han, Inkyu; Symanski, Elaine; Stock, Thomas H

    2017-03-01

    Exposure to ambient particulate matter (PM) is known as a significant risk factor for mortality and morbidity due to cardiorespiratory causes. Owing to increased interest in assessing personal and community exposures to PM, we evaluated the feasibility of employing a low-cost portable direct-reading instrument for measurement of ambient air PM exposure. A Dylos DC 1700 PM sensor was collocated with a Grimm 11-R in an urban residential area of Houston Texas. The 1-min averages of particle number concentrations for sizes between 0.5 and 2.5 µm (small size) and sizes larger than 2.5 µm (large size) from a DC 1700 were compared with the 1-min averages of PM2.5 (aerodynamic size less than 2.5 µm) and coarse PM (aerodynamic size between 2.5 and 10 µm) concentrations from a Grimm 11-R. We used a linear regression equation to convert DC 1700 number concentrations to mass concentrations, utilizing measurements from the Grimm 11-R. The estimated average DC 1700 PM2.5 concentration (13.2 ± 13.7 µg/m(3)) was similar to the average measured Grimm 11-R PM2.5 concentration (11.3 ± 15.1 µg/m(3)). The overall correlation (r(2)) for PM2.5 between the DC 1700 and Grimm 11-R was 0.778. The estimated average coarse PM concentration from the DC 1700 (5.6 ± 12.1 µg/m(3)) was also similar to that measured with the Grimm 11-R (4.8 ± 16.5 µg/m(3)) with an r(2) of 0.481. The effects of relative humidity and particle size on the association between the DC 1700 and the Grimm 11-R results were also examined. The calculated PM mass concentrations from the DC 1700 were close to those measured with the Grimm 11-R when relative humidity was less than 60% for both PM2.5 and coarse PM. Particle size distribution was more important for the association of coarse PM between the DC 1700 and Grimm 11-R than it was for PM2.5. The performance of a low-cost particulate matter (PM) sensor was evaluated in an urban residential area. Both PM2.5 and coarse PM (PM10-2.5) mass concentrations were

  15. The role of nuclear particle physics in European science and education

    CERN Multimedia

    1970-01-01

    In conjunction with the formal papers presented at the session of the CERN Council reported earlier in this issue, a booklet entitled 'The European 300 GeV Accelerator Programme' (more colloquially known as 'the white book') has been prepared. It aims to present the 300 GeV project and its background in a more general way. We reproduce here the opening chapter which puts the research at CERN and related Laboratories in Europe in the context of European science and education.

  16. Cake properties in ultrafiltration of TiO2 fine particles combined with HA: in situ measurement of cake thickness by fluid dynamic gauging and CFD calculation of imposed shear stress for cake controlling.

    Science.gov (United States)

    Du, Xing; Qu, Fangshu; Liang, Heng; Li, Kai; Chang, Haiqing; Li, Guibai

    2016-05-01

    In this study, the cake buildup of TiO2 fine particles in the presence of humid acid (HA) and cake layer controlling during ultrafiltration (UF) were investigated. Specifically, we measured the cake thickness using fluid dynamic gauging (FDG) method under various solution conditions, including TiO2 concentration (0.1-0.5 g/L), HA concentration (0-5 mg/L, total organic carbon (TOC)), and pH values (e.g., 4, 6 and 10), and calculated the shear stress distribution induced by stirring using computational fluid dynamics (CFD) to analyze the cake layer controlling conditions, including the operation flux (50-200 L m(-2) h(-1)) and TiO2 concentration (0.1-0.5 g/L). It was found that lower TiO2/HA concentration ratio could lead to exceedingly severe membrane fouling because of the formation of a relatively denser cake layer by filling the voids of cake layer with HA, and pH was essential for cake layer formation owing to the net repulsion between particles. Additionally, it was observed that shear stress was rewarding for mitigating cake growth under lower operation flux as a result of sufficient back-transport forces, and exhibited an excellent performance on cake layer controlling in lower TiO2 concentrations due to slight interaction forces on the vicinity of membrane.

  17. 浆料系统内上升气泡周围微细颗粒浓度分布和附着效率的理论研究%Theoretical Approach to Concentration Distribution and Adhesion Efficiency of Fine Particles Around a Rising Bubble in Slurry Systems

    Institute of Scientific and Technical Information of China (English)

    蔡旺锋; 许春建; 周明

    2002-01-01

    Quantitative prediction of distribution function and adhesion efficiency of particles around a risingbubble in slurry systems is presented in this work. By solving the convection-diffusion equation (Fokker-Planckequation), the influence of Brownian diffusivity of fine particles on concentration distribution and adhesion efficiencyis demonstrated with the hydrodynamic force and van der Waals attractive potential between particles and bubbleconsidered. It is found that two kinds of mechanism dominate the adhesion process of particles on bubble accordingaddition, the viscosity ratio of bubble to the suspending fluid was found to have obvious influence on particleadhesion.

  18. Laboratory Investigations in Support of Carbon Dioxide-in-Water Emulsions Stabilized by Fine Particles for Ocean and Geologic Sequestration of Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Dan Golomb; Eugene Barry; David Ryan

    2006-07-08

    This semi-annual progress report includes our latest research on deep ocean sequestration of CO{sub 2}-in-Water (C/W) emulsions stabilized by pulverized limestone (CaCO{sub 3}). We describe a practical system that could be employed for the release of a dense C/W emulsion. The heart of the system is a Kenics-type static mixer. The testing and evaluation of a static mixer in the NETL High-Pressure Water Tunnel Facility was described in the previous semi-annual report. The release system could be deployed from a floating platform over the open ocean, or at the end of an off-shore pipe laying on the continental slope. Because the emulsion is much denser than ambient seawater, modeling shows that upon release the plume will sink much deeper from the injection point, increasing the sequestration time for CO{sub 2}. When released in the open ocean, a plume containing the output of a 500 MW{sub el} coal-fired power plant will typically sink hundreds of meters below the injection point. When released from a pipe on the continental shelf, the plume will sink about twice as much because of the limited entrainment of ambient seawater when the plume flows along the sloping seabed. Furthermore, the plume is slightly alkaline, not acidic. The disadvantage is that the creation of the emulsion requires significant amounts of pulverized limestone, on the order of 0.5-0.75 weight ratio of limestone to CO{sub 2}. While pulverized limestone with particle size appropriate for creating C/W emulsions can be purchased for $38 per ton, it is shown in this report that it may be more economic to purchase raw limestone from quarries and pulverize it in situ using grinding mills. In this case the major cost elements are the capital and operating costs of the grinding mills, resulting in a total cost of about $11 per ton of pulverized limestone, including the cost of raw material and shipping. Because we need approximately 0.75 ton of pulverized limestone per ton of liquid CO2 to create a stable

  19. Brownian agents and active particles collective dynamics in the natural and social sciences

    CERN Document Server

    Schweitzer, Frank

    2007-01-01

    ""This book lays out a vision for a coherent framework for understanding complex systems"" (from the foreword by J. Doyne Farmer). By developing the genuine idea of Brownian agents, the author combines concepts from informatics, such as multiagent systems, with approaches of statistical many-particle physics. This way, an efficient method for computer simulations of complex systems is developed which is also accessible to analytical investigations and quantitative predictions. The book demonstrates that Brownian agent models can be successfully applied in many different contexts, ranging from

  20. Hypersensitivity of prediabetic JCR:LA-cp rats to fine airborne combustion particle-induced direct and noradrenergic-mediated vascular contraction.

    Science.gov (United States)

    Proctor, Spencer D; Dreher, Kevin L; Kelly, Sandra E; Russell, James C

    2006-04-01

    Particulate matter with mean aerodynamic diameter JCR:LA-cp rat. Residual oil fly ash leachate (ROFA-L) was studied using aortic rings from young-adult, obese, insulin-resistant rats and lean normal rats in vitro. Contractile response to phenylephrine and relaxant response to acetylcholine were determined in the presence and absence of L-NAME (N(G)-nitro-L-arginine methyl ester). In a separate series of studies, the direct contractile effects of ROFA-L on repeated exposure were determined. ROFA-L (12.5 microg ml(-1)) increased phenylephrine-mediated contraction in obese (p < 0.05), but not in lean rat aortae, with the effect being exacerbated by L-NAME, and it reduced acetylcholine-mediated relaxation of both obese and lean aortae (p < 0.0001). Initial exposure of aortae to ROFA-L caused a small contractile response (<0.05 g), which was markedly greater on second exposure in the obese (approximately 0.6 g, p < 0.0001) aortae but marginal in lean (approximately 0.1 g) aortae. Our data demonstrate that bioavailable constituents of oil combustion particles enhance noradrenergic-mediated vascular contraction, impair endothelium-mediated relaxation, and induce direct vasocontraction in prediabetic rats. These observations provide the first direct evidence of the causal properties of PM(2.5) and identify the pathophysiological role of the early prediabetic state in susceptibility to environmentally induced cardiovascular disease. These are important implications for public health and public policy.

  1. Kinetic study of phytotoxicity induced by foliar lead uptake for vegetables exposed to fine particles and implications for sustainable urban agriculture.

    Science.gov (United States)

    Xiong, TianTian; Austruy, Annabelle; Pierart, Antoine; Shahid, Muhammad; Schreck, Eva; Mombo, Stéphane; Dumat, Camille

    2016-08-01

    At the global scale, foliar metal transfer occurs for consumed vegetables cultivated in numerous urban or industrial areas with a polluted atmosphere. However, the kinetics of metal uptake, translocation and involved phytotoxicity was never jointly studied with vegetables exposed to micronic and sub-micronic particles (PM). Different leafy vegetables (lettuces and cabbages) cultivated in RHIZOtest® devices were, therefore, exposed in a greenhouse for 5, 10 and 15days to various PbO PM doses. The kinetics of transfer and phytotoxicity was assessed in relation to lead concentration and exposure duration. A significant Pb accumulation in leaves (up to 7392mg/kg dry weight (DW) in lettuce) with translocation to roots was observed. Lead foliar exposure resulted in significant phytotoxicity, lipid composition change, a decrease of plant shoot growth (up to 68.2% in lettuce) and net photosynthesis (up to 58% in lettuce). The phytotoxicity results indicated plant adaptation to Pb and a higher sensitivity of lettuce in comparison with cabbage. Air quality needs, therefore, to be considered for the health and quality of vegetables grown in polluted areas, such as certain megacities (in China, Pakistan, Europe, etc.) and furthermore, to assess the health risks associated with their consumption.

  2. Molecular characterisation of organic material in air fine particles (PM10) using conventional and reactive pyrolysis-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Fabbri, Daniele; Prati, Silvia; Vassura, Ivano

    2002-04-01

    Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was applied to study the composition of organic constituents in air particulate matter (PM10) collected inside an industrial area. A few milligrams of sampling filters containing air particles were pyrolysed at 700 degrees C directly (conventional) or after the addition of a derivatising reagent (tetramethylammonium hydroxide, TMAH, for pyrolysis-methylation; hexamethyldisilazane, HMDS, for pyrolysis-silylation). Py-GC-MS was also applied to synthetic polymers (poly(styrene-co-isoprene), polylimonene and polypinene) and vegetation samples (coniferous pollen, bark and resin) to identify markers indicative of possible precursors. Pyrolysates of PM10 showed the same suite of compounds in all the four seasons, dominated by hydrocarbons like styrene, limonene and clusters of isomeric alkenes with 14, 15 and 16 carbon atoms. Pyrolysis products of natural origin, including furaldehyde, benzeneacetonitrile, dehydroabietin and other diterpenoids were found, while no specific markers of synthetic rubbers were detected. The principal products released from reactive pyrolysis of PM10 were methyl or trimethylsilyl (TMS) derivatives of 1,6-anhydroglucose (levoglucosan), fatty acids, dehydroabietic acid and other resin acids along with hydroxy (di)carboxylic acids. Possible sources of the detected products (e.g. pine forest, biomass combustion) are discussed.

  3. ChemCam analysis of Martian fine dust

    Science.gov (United States)

    Lasue, Jeremie; Mangold, Nicolas; Cousin, Agnes; Meslin, Pierre-Yves; Wiens, Roger; Gasnault, Olivier; Rapin, William; Schroder, Susanne; Ollila, Ann; Fabre, Cécile; Berger, Gilles; Le Mouélic, Stéphane; Dehouck, Erwin; Forni, Olivier; Maurice, Sylvestre; Anderson, Ryan; Bridges, Nathan; Clark, Benton; Clegg, Samuel; d'Uston, Claude; Goetz, Walter; Johnson, Jeffrey R.; Lanza, Nina; Madsen, Morten; Melikechi, Noureddine; Newsom, Horton; Sautter, Violaine; Martin-Torres, Javier; Zorzano, Maria-Paz; MSL Science Team

    2016-10-01

    In this work, we examine the chemical composition of dust observed by the Chemistry Camera (ChemCam) instrument onboard the Mars Science Laboratory (MSL) rover at Gale Crater. The Laser Induced Breakdown Spectroscopy technique analyses samples without preparation, which allows detection of the elemental composition of surface deposits. Mars aeolian fine dust (soils encountered at Gale crater. The composition is also similar to the soils and fine dust measured by APXS for the elements common to both instruments. The minor elements quantified by ChemCam (Ba, Sr, Rb, Li, Mn, Cr) are within the range of soil surveys, but we see a higher concentration of Li than in other types of remotely characterized targets. Sulfur is possibly detected at the ChemCam limit of detection. Hydrogen is clearly identified, indicating that this fine dust is a contributor to the H content of the martian soils, as also detected by the SAM and CheMin instruments, and provides constraints as to which fraction of the Martian surface is hydrated and altered. In conclusion, the finest fraction of dust particles on the surface of Mars contains hydrated components mixed intimately within the fine aeolian dust fraction, suggesting that this dust likely originates from mechanical weathering of altered grains.

  4. An investigation of upland erosion and sources of fine-sediment using aerial and terrestrial LiDAR, mineralogy, geochemistry, and particle-size, Humbug Creek and Malakoff Diggings State Historic Park, California

    Science.gov (United States)

    Curtis, J.; Alpers, C. N.; Howle, J.; Monohan, C.; Ward, J.; Bailey, T. L.; Walck, C.

    2015-12-01

    One of the largest hydraulic mines (1.6 km2) is located in California's Sierra Nevada within the Humbug Creek watershed and Malakoff Diggins State Historic Park (MDSHP). Previous work indicates typical annual discharge from Humbug Creek of > 500,000 kg of sediment and > 100 g of mercury. This study uses photogrammetry and repeat high-resolution topographic surveys to quantify erosion rates and geomorphic processes, and sediment "fingerprinting" to quantify contributions of fine-sediment sources. The headwaters of Humbug Creek are underlain by volcanic mudflows, whereas MDSHP's denuded and dissected landscape is composed of weathered auriferous sediments susceptible to chronic rill and gully erosion with block failures and debris flows occurring in more cohesive terrain. Aerial LiDAR (November 2014) was used to create a 1-meter digital elevation model (DEM); photogrammetry will be used to create a pre-1997 DEM from historic aerial photographs. DEM differencing will provide an integrated estimate of long-term erosion averaged over ~20 years in unvegetated areas. Finer-resolution (1-cm) terrestrial LiDAR (T-LiDAR) scans were made in late 2014 at four pit locations and will be repeated in the fall of 2015 and 2016. The T-LiDAR time series will provide annual erosion rates under modern conditions, allowing assessment of relative contributions from shallow surface processes and deeper gravity-driven processes. In 2014‒15 we collected storm runoff and in-situ hillslope samples. Sediment fingerprints (mineralogy, major elements, trace elements, and particle size) for source sediments will be used to assess relative contributions from fine-sediment sources using a statistical mixing model. We will present our approach, preliminary results, and discuss how this study supports selection and implementation of management and remediation strategies to ameliorate the discharge of sediment and mercury and mitigate downstream water-quality impacts.

  5. Health effects of exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Pihlava, T.; Uuppo, M.; Niemi, S.

    2013-11-01

    This report introduces general information about diesel particles and their health effects. The purpose of this report is to introduce particulate matter pollution and present some recent studies made regarding the health effects of particulate matter. The aim is not to go very deeply into the science, but instead to keep the text understandable for the average layman. Particulate matter is a complex mixture of extremely small particles and liquid droplets. These small particles are made up of a number of components that include for example acids, such as nitrates and sulphates, as well as organic chemicals, metals and dust particles from the soil. Particulate matter comes from several sources, such as transportation emissions, industrial emissions, forest fires, cigarette smoke, volcanic ash and climate variations. Particles are divided into coarse particles with diameters less than 10 ..m, fine particles with diameters smaller than 2.5 ..m and ultra-fine particles with diameters less than 0.1 ..m. The particulate matter in diesel exhaust gas is a highly complex mixture of organic, inorganic, solid, volatile and partly volatile compounds. Many of these particles do not form until they reach the air. Many carcinogenic compounds have been found in diesel exhaust gas and it is considered carcinogenic to humans. Particulate matter can cause several health effects, such as premature death in persons with heart or lung disease, cancer, nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function and an increase in respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing. It is estimated that in Finland about 1300 people die prematurely due to particles and the economic loss in the EU due to the health effects of particles can be calculated in the billions. Ultra-fine particles are considered to be the most harmful to human health. Ultrafine particles usually make the most of their quantity and surface area

  6. Study of SiC Layer with Fine Grains in HTGR Coated Fuel Particles%HTGR 包覆燃料颗粒碳化硅层细晶化研究

    Institute of Scientific and Technical Information of China (English)

    刘荣正; 刘马林; 刘兵; 邵友林

    2015-01-01

    高温气冷堆(HTGR)是能适应未来能源市场的第四代先进核反应堆堆型之一,其固有安全性的第一道保障是使用的T RISO型包覆燃料颗粒。在T RISO型燃料颗粒4层包覆结构中,SiC包覆层是承受包覆燃料颗粒内压和阻挡裂变产物释放的关键层,制备高质量S iC包覆层是核燃料领域中的重大问题和关键技术之一。本文介绍高温气冷堆燃料颗粒的基本结构,详述制备S iC包覆层的流化床‐化学气相沉积过程,提出S iC层细晶化这一研究方向,并系统阐述包覆燃料颗粒S iC包覆层细晶化的优势。在细晶化S iC材料制备方法方面,系统分析S iC粉体、陶瓷、薄膜和厚膜材料的研究现状,并结合本实验室前期研究成果提出制备细晶S iC包覆层的可行制备策略。%High temperature gas‐cooled reactor (HTGR) with inherent safety character‐istics is considered as one of the attractive and competitive generation Ⅳ nuclear reactors in the future energy markets .Tristructural‐isotropic (TRISO)‐coated particle fuel is the most significant safety aspect in this nuclear reactor ,since it relies on the properties of the four coating layers surrounding the kernel fuel to hinder the release of harmful radio‐active material .Among these layers ,the silicon carbide (SiC) coating is considered the most important as it not only provides the TRISO particle with structural integrity but also retains fission products at elevated temperatures .The preparation of high quality SiC layers is one of significant issues and key technologies in nuclear fuel fabrication . T he basic structure of the T RISO‐coated fuel particles and the fluidized bed chemical vapor deposition (FBCVD) method to prepare SiC layers were introduced .The advanta‐ges of decreasing grain size of SiC layers were analyzed and the idea to prepare SiC layers with fine grain size was proposed .In the preparation strategies ,recent

  7. Long-term trends of chemical characteristics and sources of fine particle in Foshan City, Pearl River Delta: 2008-2014.

    Science.gov (United States)

    Tan, Jihua; Duan, Jingchun; Ma, Yongliang; He, Kebin; Cheng, Yuan; Deng, Si-Xin; Huang, Yan-Ling; Si-Tu, Shu-Ping

    2016-09-15

    Foshan is a major international ceramic center and the most polluted city in the Pearl River Delta (PRD). Here we present the results of the first long-term PM2.5 (particles <2.5μm) sampling and chemical characterization study of the city. A total of 2774 samples were collected at six sites from 2008 to 2014, and analyzed for water soluble species, elements and carbonaceous species. The major constituents of PM2.5 were sulfate, OC (Organic Carbon), nitrate, ammonium and EC (Elemental Carbon), which accounted for 50%-88% of PM2.5. PM2.5 and the most abundant chemical species decreased from 2008 to 2011, but rebounded in 2012-2013. After 2008, the chemical composition of PM2.5 changed dramatically due to the implementation of pollution control measures. From 2008 to 2011, SO4(2-) and NO3(-) were the two largest components; subsequently, however, OC was the largest component. The respective contributions of SO4(2-), NO3(-) and OC to the sum of water soluble species and carbonaceous species were 30.5%, 22.9% and 19.9% in 2008; and 20.2%, 16.5% and 30.2% in 2014. Distinct differences in nitrate and sulfate, and in mass ratio [NO3(-)]/[SO4(2-)] imply that mobile sources tended to more important in Foshan during 2012-2014. The results indicate that pollution control measures implemented during 2008-2014 had a large effect on anthropogenic elements (Pb, As, Cd, Zn and Cu) and water soluble species, but little influence on crustal elements (V, Mn, Ti, Ba and Fe) and carbonaceous species. The PMF method was used for source apportionment of PM2.5. Industry (including the ceramic industry and coal combustion), vehicles and dust were the three most important sources and comprised 39.2%, 20.0% and 18.4% of PM2.5 in 2008, respectively. However, secondary aerosols, vehicles and industry were the three most important sources and comprised 29.5%, 22.4% and 20.4% of PM2.5 in 2014, respectively. During the seven year study interval, the contributions of primary sources (industry and

  8. Hidden $U(1)_Y$ Ward-Takahashi identities, absence of Brout-Englert-Higgs fine-tuning, decoupling of certain heavy particles, due to spontaneous symmetry breaking II: The Abelian Higgs model (AHM), extended-AHM, derivations and examples

    CERN Document Server

    Lynn, Bryan W

    2015-01-01

    This work is dedicated to the memory of R. Stora. The spontaneously broken (SSB) $U(1)_Y$ Abelian Higgs model (AHM) (the gauge theory of a scalar $\\phi \\propto (H+i\\pi)= {\\tilde H}e^{i{\\tilde \\pi}/}$ and a transverse vector A) has a massless pseudo-scalar $\\pi$ in Lorenz gauge. Physical states have a conserved global current and Goldstone theorem (GT). $\\tilde \\pi$ becomes a Nambu-Goldstone boson (NGB). Slavnov-Taylor identities keep on-shell T-matrix elements of physical states independent of anomaly-free gauge, and global, transformations, yielding towers of $\\phi$-sector Ward-Takahashi Identities (WTI), and constraining external $\\phi$ dynamics. Ultraviolet quadratic divergences (UVQD) contribute only to $m_\\pi^2$, forced by the GT to 0, so all UVQD vanish. Weak-scale renormalized gauge-independent Higgs pole-mass and VEV are therefore not fine-tuned. The NGB is "eaten" and decouples, hiding the $U(1)_Y$ WTI from observable particle physics. Our regularization-scheme-independent results are unchanged by th...

  9. 古叙矿区选煤厂细粒级分级入洗工艺的探讨和分析%Discussion and analysis on fine particle grading in washing process in Guxu coal preparation plant

    Institute of Scientific and Technical Information of China (English)

    杨泽伟; 王川

    2013-01-01

    针对选煤厂高度泥化煤质煤泥水处理的问题进行探讨,对古叙矿区原煤伴生矿及其夹矸高度泥化的特征进行了分析试验,同时对现有细粒级分级设备的优缺点进行了对比,并结合企业煤炭产品结构及对选煤厂生产成本进行了分析,从而选择在技术经济和经营结构上都较为合理的选煤工艺及设备选型。%In view of the problems of coal slurry water treatment of high argillization coal, the characters of raw ore in Guxu minging area and gangue with highly argillization have been tested and analyzed.Meanwhile,the advantages and disadvantages of existing fine particle gradG ing equipment have been compared,and after combined with the analyzation of coal product structure and production costs in coal preparation plant,the reasonable coal preparation process and equipment have been selection based on technical economic and business structures.

  10. Preparation of Ultra-fine Salbutamol Sulfate Particles by Reactive Precipitation and Characterization of Dry Powder Inhalant%反应沉淀法制备超细硫酸沙丁胺醇颗粒及其粉雾剂的表征

    Institute of Scientific and Technical Information of China (English)

    续京; 刘晓林; 陈建峰

    2008-01-01

    The preparation of ultra.fine particles of salbutamol sulphate(SS)was accomplished with a reactive precipitation pathway,in Which salbutamo]and sulphuric acid were used as reactants wlth the solvents of ethanol.The effects of sulphuric acid concentration.reaction temperature,stirring rate,and reaction time on the Size of the particle were investigated.A binary mixture composed of lactose and SS was prepared to evaluate SS.The results showed that ultra-fine SS particles with controlled diameters ranging between 3 grn and 0.8 μm and with a narrow distribution could be achieyed.The morphology consisting of clubbed particles was successfully obtained.The pu-fity of the particles reached above 98%with UV detection.The dose of dry powder inhalation was obtained by blending the particles with recrystallized lactose.which acted as a carrier.The deposition quantity of the drug in breathing tract was estimated using a twin impinger apparatus.Compared wlth the Shapuer powder(purchased in the market),the results showed that SS particles had more quantines subsided in simulative lung.

  11. Agglomeration removal of fine particles at super-saturation steam by using acoustic wave%燃煤细颗粒在过饱和氛围下声波团聚脱除的实验研究

    Institute of Scientific and Technical Information of China (English)

    颜金培; 陈立奇; 杨林军

    2014-01-01

    An experimental installation was set up for investigating experimentally agglomeration removal of dust particles under various steam super-saturation degrees by using acoustic wave. The results show that the acoustic wave entrainment coefficient for these fine particles goes up with increase of the super-saturation degree, leading to improvement of the removal efficiencies. When the super-saturation degree is below 1.0,the total removal efficiency of dust particles has almost no increase with it, and is quite low, about 10%. However, when the super-saturation degree is bigger than 1.0, the total efficiency can be promoted and goes up rapidly with the increase of super-saturation degree. For example, when the super-saturation degree increases from 1.0 to 1.5, the removal efficiency rises about 50%. The removal efficiency of dust particles increases also with rising sound pressure level. Even if at high sound pressure steam condensational growth can not occur yet at 0.3 of low steam super-saturation degree, hence, only low removal efficiency, less than 20%, is observed. But at 1.2 of high steam super-saturation degree, the removal efficiency can be significantly improved, for example at 130dB of lower sound pressure level, about 70% high efficiency can be obtained. These facts indicate that removal of dust particles can be effectively improved if acoustic wave is used, i.e. their agglomeration with steam can be enlarged.%在不同过饱和氛围下,建立了燃煤细颗粒在声波场中团聚长大脱除的实验装置,对细颗粒物在声波场和不同过饱和氛围下的团聚长大脱除特性进行了实验研究。结果表明:细颗粒在声波场中的夹带系数随过饱和度的增大而增加,相应的脱除效率也有所提高;在过饱和度低于1.0时,细颗粒的总脱除效率很低(约为10%),且几乎不随过饱和度的增大而增加,而当过饱和度大于1.0后,细颗粒的脱除效率随过饱和度的增大而

  12. Characterization of fine particles using optomagnetic measurements

    DEFF Research Database (Denmark)

    Fock, Jeppe; Jonasson, Christian; Johansson, Christer

    2017-01-01

    The remanent magnetic moment and the hydrodynamic size are important parameters for the synthesis and applications of magnetic nanoparticles (MNPs). We present the theoretical basis for the determination of the remanent magnetic moment and the hydrodynamic size of MNPs with a narrow size...

  13. Southern Fine Particulate Monitoring Project

    Energy Technology Data Exchange (ETDEWEB)

    Ashley Williamson

    2003-05-31

    This final project report presents experimental details, results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the October, 2001-September, 2002 study period.The host site for these measurement activities is the North Birmingham PM monitoring station by the Jefferson County Health Department in Birmingham, AL.The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. During the course of the project, measurement intercomparison data were developed for these instruments and several complementary measurements at the site. The report details the instrument set and operating procedures and describes the resulting data. Report subsections present an overview summary of the data, followed by detailed description of the systematic time behavior of PM{sub 2.5} and other specific particulate size fractions. Specific subsections are included for particle size distribution, light scattering, and particle sulfate data. The final subsection addresses application of the measurements to the practical questions of fine PM generation and transport, source attribution, and PM{sub 2.5} management strategies.

  14. Fine pitch CdTe-based Hard-X-ray polarimeter performance for space science in the 70-300 keV energy range

    CERN Document Server

    Antier, S; Ferrando, P

    2015-01-01

    X-rays astrophysical sources have been almost exclusively characterized through imaging, spectroscopy and timing analysis. Nevertheless, more observational parameters are needed because some radiation mechanisms present in neutrons stars or black holes are still unclear. Polarization measurements will play a key role in discrimination between different X-ray emission models. Such a capability becomes a mandatory requirement for the next generation of high-energy space proposals. We have developed a CdTe-based fine-pitch imaging spectrometer, Caliste, able to respond to these new requirements. With a 580-micron pitch and 1 keV energy resolution at 60 keV, we are able to accurately reconstruct the polarization angle and polarization fraction of an impinging flux of photons which are scattered by 90{\\deg} after Compton diffusion within the crystal. Thanks to its high performance in both imaging and spectrometry, Caliste turns out to be a powerful device for high-energy polarimetry. In this paper, we present the ...

  15. Oil-particle interactions and submergence from crude oil spills in marine and freshwater environments: review of the science and future research needs

    Science.gov (United States)

    Fitzpatrick, Faith A.; Boufadel, Michael C.; Johnson, Rex; Lee, Kenneth W.; Graan, Thomas P.; Bejarano, Adriana C.; Zhu, Zhenduo; Waterman, David; Capone, Daniel M.; Hayter, Earl; Hamilton, Stephen K.; Dekker, Timothy; Garcia, Marcelo H.; Hassan, Jacob S.

    2015-01-01

    Oil-particle interactions and oil submergence are of much interest to oil spill responders and scientists, especially as transportation of light and heavy crude oils increases in North America’s coastal marine and freshwater environments. This report contains an up-to-date review of the state of the science for oil-particle aggregates (OPAs), in terms of their formation and stability which may alter the transport, fate, and toxicity of the residual oil and, hence, its level of ecological risk. Operational considerations—detection, containment, and recovery—are discussed.

  16. Relación entre las partículas finas (PM 2.5 y respirables PM 10 en la ciudad de Medellín Relation between fine particles (PM 2.5 and breathable particles (PM 10 in Medellin city

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Echeverri Londoño

    2008-01-01

    Full Text Available En este trabajo se presenta parte de los resultados del proyecto 'Patologías respiratorias en niños preescolares y su relación con la contaminación atmosférica de Medellín', realizado por la Universidad de Medellín y la Universidad CES para la Secretaria de Salud de Medellín dentro del contrato 4700026668 de 2006. Se realizaron mediciones simultáneas de partículas finas (PM2.5 y respirables (PM10 durante el período de febrero a octubre de 2007 en varios sitios de la ciudad de Medellín, capital del departamento de Antioquia, habitada aproximadamente por 2’250.000 personas. Los resultados del análisis muestran, en la mayoría de los casos, una correlación positiva y lineal entre los dos parámetros. La relación (PM2.5/PM10 promedio para los sitios o zonas bajo consideración en este estudio fue de aproximadamente 0.67, valor bastante considerable que hace pensar que probablemente se puede cumplir con la norma anual para PM10, pero no para PM2.5. Los resultados obtenidos identifican las partículas finas como uno de los principales problemas de contaminación en la ciudad de Medellín.This article shows part of the results from the project called: 'Respiratory pathologies in pre-school children and their relation to atmospheric contamination in Medellin,' carried out by Universidad de Medellin and Universidad CES for Medellin Health Secretariat according to contract No. 4700026668, year 2006. Simultaneous measurements of fine particles (PM2.5 and breathable particles (PM10 were made from February to October, 2007 in several sites of Medellin, the capital city of Antioquia State, where about 2,250,000 inhabitants live. In almost all cases, analysis results show a positive and linear correlation between both parameters. Average ratio (PM2.5/PM10 for sites and zones tested in this study was 0.67 approximately, which is a very meaningful value, what makes us think that annual norm for PM10 can probably be accomplished, but not the one

  17. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  18. Fine Particles Formation During O2/CO2 Combustion of Low-rank Coal%低阶煤O2/CO2气氛下燃烧生成颗粒物的特性

    Institute of Scientific and Technical Information of China (English)

    汪应红; 王群英; 付晓恒

    2012-01-01

    选取了2种低阶煤在不同气氛下沉降炉中进行燃烧实验,产生的灰颗收集到粒旋风分离器和低压冲击器中,利用透射电子显微镜和扫描电镜分析亚微米颗粒和超微米颗粒的形态,利用扫描电镜能量色散谱仪联用,透射电子显微镜能量色散谱仪联用和计算机控制的扫描电镜分析灰颗粒的化学元素组成.研究结果表明:O2/CO2燃烧改变超细颗粒物的大小分布和灰中元素的浓度分布,但没有改变细颗粒的生成机制.对于含有更多有机结构矿物质的褐煤,O2/CO2燃烧提高了Fe、Na/K、A1和Si的气化程度,也因此增加了亚微颗粒的浓度,而且褐煤中的Fe元素的气化较为特殊,O2/CO2燃烧氧气浓度的增加提高了Fe气化后在其他粒子上的附着.%Two kinds of typical low-rank coal were burned in a drop tube furnace under different atmosphere. The produced particulate matters(PM) were collected by the cyclone and low pressure impactor(LPI). Transmission electron microscopy(TEM) and scanning electron microscope (SEM) were used to identify the morphology of the super-micron and submicron PM. SEM with an energy dispersive X-ray(SEM-EDX), TEM with an energy dispersive X-ray spectroscopy(TEM-EDS) and computer-controlled scanning electron microcopy(CCSEM) were applied to analyze the chemical composition in the ash. It has been confirmed that compared with air atmosphere, O2/CO2 atmosphere changes the generated fine ash particle size distribution and the concentration of the chemical composition, but the formation mechanisms are same for different atmosphere. For the case of the lignite with more amount of organic-associated minerals, O2/CO2 atmosphere increase the vaporization degree of Fe, Na/K sulfates, Al and Si, and thus increase the concentration of sub-micron particles. Also Fe is found to be a key element in the lignite. Oxy-fuel-combustion increases the attachment of vaporized Fe element to other particle.

  19. The role of very fine particle sizes in the reflectance spectroscopy of plagioclase-bearing mixtures: New understanding for the interpretation of the finest sizes of the lunar regolith

    Science.gov (United States)

    Serventi, Giovanna; Carli, Cristian

    2017-09-01

    The lunar surface consists of a regolith layer that covers the underlying bedrocks, and is generally characterized by particulates minerals. Due to the more feldspathic nature of the very fine<