WorldWideScience

Sample records for resin fine particles

  1. 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.

  2. Aerosol-phase activity of iodine captured from a triiodide resin filter on fine particles containing an infectious virus.

    Science.gov (United States)

    Heimbuch, B K; Harnish, D A; Balzli, C; Lumley, A; Kinney, K; Wander, J D

    2015-06-01

    To avoid interference by water-iodine disinfection chemistry and measure directly the effect of iodine, captured from a triiodide complex bound to a filter medium, on viability of penetrating viral particles. Aerosols of MS2 coli phage were passed through control P100 or iodinated High-Efficiency Particulate Air media, collected in plastic bags, incubated for 0-10 min, collected in an impinger containing thiosulphate to consume all unreacted iodine, plated and enumerated. Comparison of viable counts demonstrated antimicrobial activity with an apparent half-life for devitalization in tens of seconds; rate of kill decreased at low humidity and free iodine was captured by the bags. The results support the mechanism of near-contact capture earlier proposed; however, the disinfection chemistry in the aerosol phase is very slow on the time scale of inhalation. This study shows that disinfection by filter-bound iodine in the aerosol phase is too slow to be clinically significant in individual respiratory protection, but that it might be of benefit to limit airborne transmission of infections in enclosed areas. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  3. Making of polymer fine particles

    International Nuclear Information System (INIS)

    Ono, Isamu

    1990-01-01

    The polymer particles having spherical shape and uniform grain diameter are applied to various fields such as powder coating, cosmetics, medicines, foods and others. These polymer fine particles are synthesized from monomers at the temperature higher than room temperature by emulsifying polymerization, suspension polymerization or dispersion polymerization, using polymerization initiator. The diameter of such synthesized fine particles is from 0.1 to 10 μm. In this study, the method of synthesizing polymer fine particles by dispersion radiation polymerization process without using polymerization initiator and emulsifying agent was examined. Monomers are dissolved in the solvent, in which monomers are soluble but polymers are insoluble, and by polymerizing with radiation, polymer fine particles are synthesized. It has the merits that additive agents are not contained, and the synthesis can be done at room temperature. The method and the results are reported. As the mechanism of forming fine particles, the reaction of beginning polymerization and the precipitation of polymers are explained. By controlling reaction temperature and monomer concentration, particle diameter can be adjusted. The monomers used were styrene, methyl metacrylate and vinyl acetate. (K.I.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Totsuji, Hiroo, E-mail: totsuji-09@t.okadai.jp

    2017-03-11

    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. - Highlights: • In fine particle (dusty) plasmas, the charge neutrality is much enhanced by the existence of fine particles. • The enhancement of charge neutrality generally occurs under microgravity and gravity. • Structure of fine particle clouds under gravity is determined by applying the enhanced charge neutrality.

  5. Numerical modeling of fine particle fractal aggregates in turbulent flow

    Directory of Open Access Journals (Sweden)

    Cao Feifeng

    2015-01-01

    Full Text Available A method for prediction of fine particle transport in a turbulent flow is proposed, the interaction between particles and fluid is studied numerically, and fractal agglomerate of fine particles is analyzed using Taylor-expansion moment method. The paper provides a better understanding of fine particle dynamics in the evolved flows.

  6. 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.

  7. Probing fine magnetic particles with neutron scattering

    International Nuclear Information System (INIS)

    Pynn, R.

    1991-01-01

    Because thermal neutrons are scattered both by nuclei and by unpaired electrons, they provide an ideal probe for studying the atomic and magnetic structures of fine-grained magnetic materials, including nanocrystalline solids, thin epitaxial layers, and colloidal suspensions of magnetic particles, known as ferrofluids. Diffraction, surface reflection, and small angle neutron scattering (SANS) are the techniques used. With the exception of surface reflection, these methods are described in this article. The combination of SANS with refractive-index matching and neutron polarisation analysis is particularly powerful because it allows the magnetic and atomic structures to be determined independently. This technique has been used to study both dilute and concentrated ferrofluid suspensions of relatively monodisperse cobalt particles, subjected to a series of applied magnetic fields. The size of the cobalt particle core and the surrounding surfactant layer were determined. The measured interparticle structure factor agrees well with a recent theory that allows correlations in binary mixtures of magnetic particles to be calculated in the case of complete magnetic alignment. When one of the species in such a binary mixture is a nonmagnetic, cyclindrical macromolecule, application of a magnetic field leads to some degree of alignment of the nonmagnetic species. This result has been demonstrated with tobacco mosaic virus suspended in a water-based ferrofluid

  8. The fine particle emissions of energy production in Finland

    International Nuclear Information System (INIS)

    Ohlstroem, M.

    1998-01-01

    The main purpose of this master's thesis was to define the fine particle (PM2.5, diameter under 2,5 μm) emissions of the energy production and to compare the calculated emission factors between different energy production concepts. The purpose was also to define what is known about fine particle emissions and what should still be studied/measured. The purpose was also to compare briefly the fine particle emissions of energy production and vehicle traffic, and their correlations to the fine particle concentrations of urban air. In the theory part of this work a literature survey was made about fine particles in energy production, especially how they form and how they are separated from the flue gas. In addition, the health effects caused by fine particles, and different measuring instruments were presented briefly. In the experimental part of this work, the aim was to find out the fine particle emissions of different energy production processes by calculating specific emission factors (mg/MJ fuel ) from powerplants' annual total particulate matter emissions (t/a), which were obtained from VAHTI-database system maintained by the Finnish Environmental Institute, and by evaluating the share of fine particles from total emissions with the help of existing measurement results. Only those energy production processes which produce significantly direct emissions of solid particles have been treated (pulverised combustion and oil burners from burner combustion, fluidized bed combustion processes, grate boilers, recovery boilers and diesel engines). The processes have been classified according to boiler type, size category, main fuel and also according to dust separation devices. To be able to compare different energy production processes, shared specific emission factor have been calculated for the similar subprocesses. The fine particle emissions depend strongest on the boiler size category and dust separation devices used. Spent fuel or combustion technique does not have

  9. NARSTO fine-particle and ozone assessments

    International Nuclear Information System (INIS)

    Hales, Jeremy M.

    2003-01-01

    The NARSTO ozone and fine-particle assessments compile and present policy-relevant scientific information. - 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 Investigacion 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

  10. 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

  11. 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

  12. Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

    OpenAIRE

    Latka, Leszek; Goryachev, Sergey B.; Kozerski, Stefan; Pawlowski, Lech

    2010-01-01

    Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results ...

  13. 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...

  14. Indirect determination of particle shape of fine aggregate.

    Science.gov (United States)

    1973-01-01

    Three methods developed by various agencies for measuring indirectly the particle shapes of fine aggregates were used along with a visual classification procedure to study aggregates from eight commercial sources along with a reference sand. The meth...

  15. Flocculation of fine fluorite particles with Corynebacterium xerosis

    OpenAIRE

    Haas Sandra R.; Nascimento Fábio R.; Schneider Ivo André H.; Gaylarde Christine

    1999-01-01

    The treatment of fine particles dispersed in liquids is common in several industries and especially important in mineral processing. The efficiency of settling operations can be substantially increased by flocculation. The aim of this work was to study the flocculation of fine fluorite particles by the bacterium Corynebacterium xerosis. Flocculation tests, microelectrophoresis measurements and optical microscopy were used to evaluate flocculation. The results showed that C. xerosis cells adhe...

  16. Simple model for fine particle (dust) clouds in plasmas

    International Nuclear Information System (INIS)

    Totsuji, Hiroo

    2016-01-01

    Highlights: • Simple model of fine particle clouds in plasmas is proposed. • The model enables independent control of the size and the density. • The system with cylindrical or spherical symmetry under microgravity is treated. • The model is based on the enhanced charge neutrality in fine particle clouds. - Abstract: In the cloud of fine particles (dusts) in plasmas, the charge neutrality can be much enhanced due to large charge numbers of fine particles. The required condition is not difficult to satisfy even when their charge density is substantially smaller than electrons or ions. Based on this fact, a simple model of fine particle clouds is proposed and the cloud radius is related to the half-width, the radius where the density of surrounding plasmas drops by half, in cylindrically and spherically symmetric cases under microgravity. When fine particles are gradually introduced with parameters of surrounding plasma especially the half-width being fixed, the size of clouds first increases and then saturates at the value determined by the plasma half-width, giving a possibility to control the size and density of clouds independently.

  17. Simple model for fine particle (dust) clouds in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Totsuji, Hiroo, E-mail: totsuji-09@t.okadai.jp

    2016-04-01

    Highlights: • Simple model of fine particle clouds in plasmas is proposed. • The model enables independent control of the size and the density. • The system with cylindrical or spherical symmetry under microgravity is treated. • The model is based on the enhanced charge neutrality in fine particle clouds. - Abstract: In the cloud of fine particles (dusts) in plasmas, the charge neutrality can be much enhanced due to large charge numbers of fine particles. The required condition is not difficult to satisfy even when their charge density is substantially smaller than electrons or ions. Based on this fact, a simple model of fine particle clouds is proposed and the cloud radius is related to the half-width, the radius where the density of surrounding plasmas drops by half, in cylindrically and spherically symmetric cases under microgravity. When fine particles are gradually introduced with parameters of surrounding plasma especially the half-width being fixed, the size of clouds first increases and then saturates at the value determined by the plasma half-width, giving a possibility to control the size and density of clouds independently.

  18. Autonomous patterning of cells on microstructured fine particles

    International Nuclear Information System (INIS)

    Takeda, Iwori; Kawanabe, Masato; Kaneko, Arata

    2015-01-01

    Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5–40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. - Highlights: • PS and SiO 2 particles provide effective scaffolds for cells. • Cells that adhere to microstructured particles successfully proliferate and differentiate. • Selective adhesion and growth along the scaffold can be achieved by patterning the fine particle microstructure. • Cells adhered to flat regions migrate toward microstructured regions. • Selective adhesion by cells depends on the microstructural geometry; specifically, on the inter-line spacing

  19. Fine particle collecting method upon cutting incore structural material

    International Nuclear Information System (INIS)

    Noie, Akihiko; Karasawa, Hidetoshi

    1998-01-01

    Air bubbles generated upon cutting incore structural materials are passed through a lattice-like metal mesh to be divided finely, and then risen in pool water. The air bubbles are risen in a state where fine metal particles are contained in a carrier gas upon conducting a plasma cutting operation. The fine particles in the air bubbles are moved to the surface of the bubbles by the effect of diffusion, inertia and gravitational precipitation, and transferred to water and removed. Since the diameter of the air bubbles is decreased, the time for the transfer of the particles to the surface of the air bubbles can be shortened to increase the amount of particles transferred per time and improve the collecting efficiency. Since fine particles of radioactive metals generated upon cutting can be collected by dividing air bubbles finely, the ventilation system of an operation chamber can be simplified. In addition, cutting operation at a shallow water depth is enabled to thereby increase the degree of freedom for operations. (N.H.)

  20. 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 distribu...... of the particle size in the techniques is taken into account. The optomagnetic technique is simple, fast and does not require prior knowledge of the concentration of MNPs and it thus has the potential to be used as a routine tool for quality control of MNPs....

  1. Evaluation of inorganic particles of composite resins with nanofiller content.

    Science.gov (United States)

    Mota, Eduardo Gonçalves; Hörlle, Lucas; Oshima, Hugo Mitsuo; Hirakata, Luciana Mayumi

    2012-01-01

    The purposes of this study were evaluate by energy dispersed X-ray (EDS) and scanning electron microscopy (SEM) the inorganic particles of three nanofilled composite resins, comparing particles sizes, shape and composition, and the filler weight content by thermogravimetric analyzes (TGA). Three composite resins classified as nanofilled were selected to this study: Esthet-X; Grandio; Filtek Supreme XT. The shade was standardized (A2) for enamel (E) or dentin (D). Ten samples with 20 mg (±10 mg) of each composite resin were submitted to thermogravimetric analyzes (TGA) in order to record the filler weight content (wt%). The amount of inorganic phase ranged from 75.75 to 87 wt%, to Esthet-X (D) and Grandio (D), respectively. The filler composition was analyzed by energy dispersed X-ray (EDS), and the size and shape were evaluated by scanning electron microscopy (SEM). The filler average size (µm) obtained by SEM were: Esthet-X (E) 1.16; Esthet-X (D) 1.39; Filtek Supreme XT (E) 0.6 (nanocluster); Filtek Supreme XT (D) 1.14 (nanocluster); Grandio (E) 2.05 and Grandio (D) 3.1. Silica (SiO2), Ba and Al were observed through EDS. The shape of Esthet-X and Grandio fillers showed similar characteristics with high quantity of irregular inorganic particles and heterogeneous filler. However, Filtek Supreme XT showed spherical and regular particles with homogeneous distribution and sizes. Based in the analysis of nanofilled composites inorganic phase, inconsistencies of weight content, composition, shape and size can be stated between the literature and manufacturer's instructions.

  2. 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...

  3. Source contributions to atmospheric fine carbon particle concentrations

    Science.gov (United States)

    Andrew Gray, H.; Cass, Glen R.

    A Lagrangian particle-in-cell air quality model has been developed that facilitates the study of source contributions to atmospheric fine elemental carbon and fine primary total carbon particle concentrations. Model performance was tested using spatially and temporally resolved emissions and air quality data gathered for this purpose in the Los Angeles area for the year 1982. It was shown that black elemental carbon (EC) particle concentrations in that city were dominated by emissions from diesel engines including both on-highway and off-highway applications. Fine primary total carbon particle concentrations (TC=EC+organic carbon) resulted from the accumulation of small increments from a great variety of emission source types including both gasoline and diesel powered highway vehicles, stationary source fuel oil and gas combustion, industrial processes, paved road dust, fireplaces, cigarettes and food cooking (e.g. charbroilers). Strategies for black elemental carbon particle concentration control will of necessity need to focus on diesel engines, while controls directed at total carbon particle concentrations will have to be diversified over a great many source types.

  4. Benthic biofilm controls on fine particle dynamics in streams

    Science.gov (United States)

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

    2017-01-01

    Benthic (streambed) biofilms metabolize a substantial fraction of particulate organic matter and nutrient inputs to streams. These microbial communities comprise a significant proportion of overall biomass in headwater streams, and they present a primary control on the transformation and export of labile organic carbon. Biofilm growth has been linked to enhanced fine particle deposition and retention, a feedback that confers a distinct advantage for the acquisition and utilization of energy sources. We quantified the influence of biofilm structure on fine particle deposition and resuspension in experimental stream mesocosms. Biofilms were grown in identical 3 m recirculating flumes over periods of 18-47 days to obtain a range of biofilm characteristics. Fluorescent, 8 µm particles were introduced to each flume, and their concentrations in the water column were monitored over a 30 min period. We measured particle concentrations using a flow cytometer and mesoscale (10 µm to 1 cm) biofilm structure using optical coherence tomography. Particle deposition-resuspension dynamics were determined by fitting results to a stochastic mobile-immobile model, which showed that retention timescales for particles within the biofilm-covered streambeds followed a power-law residence time distribution. Particle retention times increased with biofilm areal coverage, biofilm roughness, and mean biofilm height. Our findings suggest that biofilm structural parameters are key predictors of particle retention in streams and rivers.

  5. Sintering of Fine Particles in Suspension Plasma Sprayed Coatings.

    Science.gov (United States)

    Latka, Leszek; Goryachev, Sergey B; Kozerski, Stefan; Pawlowski, Lech

    2010-07-01

    Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating's microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings' growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m²,depending on the experimental conditions. The theoretical section analyzes the sintering during the coating's growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension plasma spraying. The formation

  6. Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

    Directory of Open Access Journals (Sweden)

    Leszek Latka

    2010-07-01

    Full Text Available Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings’ growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m2,depending on the experimental conditions. The theoretical section analyzes the sintering during the coating’s growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension

  7. The dispersion of fine chitosan particles by beads-milling

    Science.gov (United States)

    Rochima, Emma; Utami, Safira; Hamdani, Herman; Azhary, Sundoro Yoga; Praseptiangga, Danar; Joni, I. Made; Panatarani, Camellia

    2018-02-01

    This research aimed to produce fine chitosan particles from a crab shell waste by beads-milling method by two different concentration of PEG as dispersing agent (150 and 300 wt. %). The characterization was performed to obtain the size and size distribution, the characteristics of functional groups and the degree of deacetylation. The results showed that the chitosan fine particles was obtained with a milling time 120 minutes with the best concentration of PEG 400 150 wt. %. The average particle size of the as-prepared suspension is 584 nm after addition of acetic acid solution (1%, v/v). Beads milling process did not change the glucosamine and N-acetylglucosamine content on chitosan structure which is indicated by degree of deacetylation higher than 70%. It was concluded that beads milling process can be applied to prepare chitosan fineparticles by proper adjustment in the milling time, pH and dosage of dispersing agent.

  8. Flocculation of fine fluorite particles with Corynebacterium xerosis

    Directory of Open Access Journals (Sweden)

    Haas Sandra R.

    1999-01-01

    Full Text Available The treatment of fine particles dispersed in liquids is common in several industries and especially important in mineral processing. The efficiency of settling operations can be substantially increased by flocculation. The aim of this work was to study the flocculation of fine fluorite particles by the bacterium Corynebacterium xerosis. Flocculation tests, microelectrophoresis measurements and optical microscopy were used to evaluate flocculation. The results showed that C. xerosis cells adhere to the fluorite surfaces promoting the aggregation of the particles. High quality flocs can be obtained rapidly at pH 7.0 using a cell concentration of 40 mg/l, considerably lower than previously reported in the literature. The results are discussed with reference to the surface characteristics of the mineral and of the microorganism.

  9. Dynamic Simulation of Random Packing of Polydispersive Fine Particles

    Science.gov (United States)

    Ferraz, Carlos Handrey Araujo; Marques, Samuel Apolinário

    2018-02-01

    In this paper, we perform molecular dynamic (MD) simulations to study the two-dimensional packing process of both monosized and random size particles with radii ranging from 1.0 to 7.0 μm. The initial positions as well as the radii of five thousand fine particles were defined inside a rectangular box by using a random number generator. Both the translational and rotational movements of each particle were considered in the simulations. In order to deal with interacting fine particles, we take into account both the contact forces and the long-range dispersive forces. We account for normal and static/sliding tangential friction forces between particles and between particle and wall by means of a linear model approach, while the long-range dispersive forces are computed by using a Lennard-Jones-like potential. The packing processes were studied assuming different long-range interaction strengths. We carry out statistical calculations of the different quantities studied such as packing density, mean coordination number, kinetic energy, and radial distribution function as the system evolves over time. We find that the long-range dispersive forces can strongly influence the packing process dynamics as they might form large particle clusters, depending on the intensity of the long-range interaction strength.

  10. Electron radiation curing of particle boards and fiber building boards impregnated with artificial resins

    Energy Technology Data Exchange (ETDEWEB)

    Schaudy, R.; Proksch, E. (Oesterreichisches Forschungszentrum Seibersdorf GmbH Inst. fuer Chemie)

    1980-06-01

    The hardening of wood particle boards and fiber building boards impregnated with artificial resins using a technical electron accelerator was examined. Suitable resin-monomer mixtures were selected by in-vitro-tests. A styrene-free unsaturated polyester resin and acrylic-modified melamine resins turned out be suitable, whereas other unsaturated polyesters and activators used for curing by gamma irradiation did not fit. The hardened boards showed markedly inceased hardness and reduced swelling, but only moderate weather resistance.

  11. Fine-particle characterization — An important recycling tool

    Science.gov (United States)

    Lindblom, Bo; Samuelsson, Caisa; Sandström, Åke; Ye, Guozhu

    2002-12-01

    This paper summarizes the results from different research projects on fine-particle characterization of metallurgical residues, such as hydroxide sludge, electric-arc furnace dust, and copper-converter dust. These studies demonstrated that characterization is essential for developing new recycling strategies. The basic knowledge of the chemical and physical properties of the residues obtained by the characterizations also provides necessary information on potential problems that could be encountered during the processing of such materials.

  12. Fine separation of particles via the entropic splitter

    Science.gov (United States)

    Li, Yongge; Xu, Yong; Xu, Wei; Deng, Zichen; Kurths, Jürgen

    2017-08-01

    We investigate the fine separation of particles with different sizes in an asymmetric confined channel by directing them moving to the opposite directions. Besides redesigning the geometry of the channel, we add a general rectangular wave oscillating force to enlarge the velocity differences between particles with different radii, which is important to increase the separation speed and sort particles of similar radii. The separation process is guaranteed by choosing a small period of the oscillating force and a proper partition strategy of the device length sifting particles to the left and right. The optimal set of parameters for a fixed amplitude of the oscillating force is found by the above regime. We show that by this regime the separation efficiency is significantly improved compared to the classic square wave force.

  13. A Constitutive Relationship for Gravelly Soil Considering Fine Particle Suffusion.

    Science.gov (United States)

    Zhang, Yuning; Chen, Yulong

    2017-10-23

    Suffusion erosion may occur in sandy gravel dam foundations that use suspended cutoff walls. This erosion causes a loss of fine particles, degrades the soil strength and deformation moduli, and adversely impacts the cutoff walls of the dam foundation, as well as the overlying dam body. A comprehensive evaluation of these effects requires models that quantitatively describe the effects of fine particle losses on the stress-strain relationships of sandy gravels. In this work, we propose an experimental scheme for studying these types of models, and then perform triaxial and confined compression tests to determine the effects of particle losses on the stress-strain relationships. Considering the Duncan-Chang E-B model, quantitative expressions describing the relationship between the parameters of the model and the particle losses were derived. The results show that particle losses did not alter the qualitative stress-strain characteristics of the soils; however, the soil strength and deformation moduli were degraded. By establishing the relationship between the parameters of the model and the losses, the same model can then be used to describe the relationship between sandy gravels and erosion levels that vary in both time and space.

  14. A Constitutive Relationship for Gravelly Soil Considering Fine Particle Suffusion

    Directory of Open Access Journals (Sweden)

    Yuning Zhang

    2017-10-01

    Full Text Available Suffusion erosion may occur in sandy gravel dam foundations that use suspended cutoff walls. This erosion causes a loss of fine particles, degrades the soil strength and deformation moduli, and adversely impacts the cutoff walls of the dam foundation, as well as the overlying dam body. A comprehensive evaluation of these effects requires models that quantitatively describe the effects of fine particle losses on the stress-strain relationships of sandy gravels. In this work, we propose an experimental scheme for studying these types of models, and then perform triaxial and confined compression tests to determine the effects of particle losses on the stress-strain relationships. Considering the Duncan-Chang E-B model, quantitative expressions describing the relationship between the parameters of the model and the particle losses were derived. The results show that particle losses did not alter the qualitative stress-strain characteristics of the soils; however, the soil strength and deformation moduli were degraded. By establishing the relationship between the parameters of the model and the losses, the same model can then be used to describe the relationship between sandy gravels and erosion levels that vary in both time and space.

  15. 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

  16. A novel approach to a fine particle coating using porous spherical silica as core particles.

    Science.gov (United States)

    Ishida, Makoto; Uchiyama, Jumpei; Isaji, Keiko; Suzuki, Yuta; Ikematsu, Yasuyuki; Aoki, Shigeru

    2014-08-01

    Abstract The applicability of porous spherical silica (PSS) was evaluated as core particles for pharmaceutical products by comparing it with commercial core particles such as mannitol (NP-108), sucrose and microcrystalline cellulose spheres. We investigated the physical properties of core particles, such as particle size distribution, flow properties, crushing strength, plastic limit, drying rate, hygroscopic property and aggregation degree. It was found that PSS was a core particle of small particle size, low friability, high water adsorption capacity, rapid drying rate and lower occurrence of particle aggregation, although wettability is a factor to be carefully considered. The aggregation and taste-masking ability using PSS and NP-108 as core particles were evaluated at a fluidized-bed coating process. The functional coating under the excess spray rate shows different aggregation trends and dissolution profiles between PSS and NP-108; thereby, exhibiting the formation of uniform coating under the excess spray rate in the case of PSS. This expands the range of the acceptable spray feed rates to coat fine particles, and indicates the possibility of decreasing the coating time. The results obtained in this study suggested that the core particle, which has a property like that of PSS, was useful in overcoming such disadvantages as large particle size, which feels gritty in oral cavity; particle aggregation; and the long coating time of the particle coating process. These results will enable the practical fine particle coating method by increasing the range of optimum coating conditions and decreasing the coating time in fluidized bed technology.

  17. 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.

  18. Effects of Prepolymerized Particle Size and Polymerization Kinetics on Volumetric Shrinkage of Dental Modeling Resins

    Directory of Open Access Journals (Sweden)

    Tae-Yub Kwon

    2014-01-01

    Full Text Available Dental modeling resins have been developed for use in areas where highly precise resin structures are needed. The manufacturers claim that these polymethyl methacrylate/methyl methacrylate (PMMA/MMA resins show little or no shrinkage after polymerization. This study examined the polymerization shrinkage of five dental modeling resins as well as one temporary PMMA/MMA resin (control. The morphology and the particle size of the prepolymerized PMMA powders were investigated by scanning electron microscopy and laser diffraction particle size analysis, respectively. Linear polymerization shrinkage strains of the resins were monitored for 20 minutes using a custom-made linometer, and the final values (at 20 minutes were converted into volumetric shrinkages. The final volumetric shrinkage values for the modeling resins were statistically similar (P>0.05 or significantly larger (P<0.05 than that of the control resin and were related to the polymerization kinetics (P<0.05 rather than the PMMA bead size (P=0.335. Therefore, the optimal control of the polymerization kinetics seems to be more important for producing high-precision resin structures rather than the use of dental modeling resins.

  19. Fine particles flotation of the Moatize coal/Mozambique

    Science.gov (United States)

    Castro, Amilton; de Brum, Irineu A. S.

    2017-11-01

    This study was done from a sample of coal mined at the Vale-Mozambique mine, located in Moatize district, Tete Province. The aim of this work is to analyze the reagent system in the flotation of coal fines belonging to the UCB layer. Among coal processing methods, flotation stands out as one of the most important for the concentration of this material, in particular in the treatment of fine particles. The total feed of the Vale-Mozambique processing plant is 8000 tph of coal, where 10% of this feed corresponds to the fine fraction that feeds the flotation circuit. The material used in this study had a particle size of 96% smaller than 0.25 mm. The reagents used in the flotation tests were Betacol and diesel oil as hydrophobizing agents and MIBC as frother. The range of Betacol concentrations in the first test phase was 200 g / t at 500 g / t, and in the second phase 200 g / t at 500 g / t of diesel oil and MIBC were kept constant at 300 g / t. The immediate analysis followed the Brazilian standards: NBR 8289, NBR 8293, NBR 8290, NBR 8299. The results showed that it is possible, from a feed with the ash content around 22.84%, to obtain products with levels below of 10% ash, with a mass recovery around 50%. The recovery of carbonaceous matter was also evaluated and presented positive results. Complementing this study, the effect of H2O recovery was evaluated and it was observed that for the concentrations of Betacol the recoveries ranged from 6 to 9%, and for diesel oil plus MIBC were 4 to 7%.

  20. Method of removing radioactive substances in the state of fine particles and ions in ammonium fluoride solution

    International Nuclear Information System (INIS)

    Kotoku, Takeshi; Uchikoshi, Tsuguo; Asano, Toichi; Yoshiwara, Koichi; Tezuka, Akira.

    1976-01-01

    Purpose: To recover super-fine particles of ammonium diuranate (ADU), dissolved uranium ions and β-radioactive nuclides of uranium which are contained in the radioactive liquid wastes discharged from enrichment plants. Constitution: A cationic surface active agent is added to a solution discharged from enrichment plants thus causing ADU particles to be bonded to the cationic surface active agent and attached to foams introduced into the solution, whereby the ADU particles are completely recovered through separation by floating. Thereafter, the clean solution after removal of suspended particles is passed through an ion exchange resin to remove dissolved uranium ions and β-radioactive nuclides which are daughter nuclides of uranium. (Horiuchi, T.)

  1. Iron solubility related to particle sulfur content in source emission and ambient fine particles.

    Science.gov (United States)

    Oakes, M; Ingall, E D; Lai, B; Shafer, M M; Hays, M D; Liu, Z G; Russell, A G; Weber, R J

    2012-06-19

    The chemical factors influencing iron solubility (soluble iron/total iron) were investigated in source emission (e.g., biomass burning, coal fly ash, mineral dust, and mobile exhaust) and ambient (Atlanta, GA) fine particles (PM2.5). Chemical properties (speciation and mixing state) of iron-containing particles were characterized using X-ray absorption near edge structure (XANES) spectroscopy and micro-X-ray fluorescence measurements. Bulk iron solubility (soluble iron/total iron) of the samples was quantified by leaching experiments. Major differences were observed in iron solubility in source emission samples, ranging from low solubility (iron solubility did not correspond to silicon content or Fe(II) content. However, source emission and ambient samples with high iron solubility corresponded to the sulfur content observed in single particles. A similar correspondence between bulk iron solubility and bulk sulfate content in a series of Atlanta PM2.5 fine particle samples (N = 358) further supported this trend. In addition, results of linear combination fitting experiments show the presence of iron sulfates in several high iron solubility source emission and ambient PM2.5 samples. These results suggest that the sulfate content (related to the presence of iron sulfates and/or acid-processing mechanisms by H(2)SO(4)) of iron-containing particles is an important proxy for iron solubility.

  2. Element determination of fine particles in environmental aerosols using PIXE

    International Nuclear Information System (INIS)

    Garcia O, B.; Aldape U, F.

    2007-01-01

    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)

  3. Characteristics of fine and coarse particles of natural and urban aerosols of Brazil

    International Nuclear Information System (INIS)

    Orsini, C.M.Q.; Tabacniks, M.H.; Artaxo Netto, P.E.; Andrade, M.F.; Kerr, A.

    1986-02-01

    Fine and coarse particles have been sampled from 1982 to 1985 in one natural forest seacoast site (Jureia) and five urban-industrial cities (Vitoria, Salvador, Porto Alegre, Sao Paulo, and Belo Horizonte). The time variations of concentrations in air and the relative elemental compositions of fine and coarse particle fractions, sampled by Nuclepore stacked filter units (SFU), have been determined gravimetrically and by PIXE analysis, respectively. Enrichment factors and correlation coefficients of the trace elements measured lead to unambiguous characterization of soil dust and sea salt, both major aerosol sources that emit coarse particles, and soil dust is also a significant source of fine particles. (Author) [pt

  4. Effects of adding silica particles on certain properties of resin-modified glass-ionomer cement

    OpenAIRE

    Felemban, Nayef H.; Ebrahim, Mohamed I.

    2016-01-01

    Objective: This study was conducted to evaluate the effect of incorporation of silica particles with different concentrations on some properties of resin-modified glass ionomer cement (RMGIC): Microleakage, compressive strength, tensile strength, water sorption, and solubility. Materials and Methods: Silica particle was incorporated into RMGIC powder to study its effects, one type of RMGIC (Type II visible light-cured) and three concentrations of silica particles (0.06, 0.08, and 0.1% weight)...

  5. Mechanical properties of dental resin composites by co-filling diatomite and nanosized silica particles

    International Nuclear Information System (INIS)

    Wang Hua; Zhu Meifang; Li Yaogang; Zhang Qinghong; Wang Hongzhi

    2011-01-01

    The aim of this study was to investigate the mechanical property effects of co-filling dental resin composites with porous diatomite and nanosized silica particles (OX-50). The purification of raw diatomite by acid-leaching was conducted in a hot 5 M HCl solution at 80 deg. C for 12 h. Both diatomite and nanosized SiO 2 were silanized with 3-methacryloxypropyltrimethoxysilane. The silanized inorganic particles were mixed into a dimethacrylate resin. Purified diatomite was characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy and an N 2 adsorption-desorption isotherm. Silanized inorganic particles were characterized using Fourier transform infrared spectroscopy and a thermogravimetric analysis. The mechanical properties of the composites were tested by three-point bending, compression and Vicker's microhardness. Scanning electron microscopy was used to show the cross-section morphologies of the composites. Silanization of diatomite and nanosized silica positively reinforced interactions between the resin matrix and the inorganic particles. The mechanical properties of the resin composites gradually increased with the addition of modified diatomite (m-diatomite). The fracture surfaces of the composites exhibited large fracture steps with the addition of m-diatomite. However, when the mass fraction of m-diatomite was greater than 21 wt.% with respect to modified nanosized silica (mOX-50) and constituted 70% of the resin composite by weight, the mechanical properties of the resin composites started to decline. Thus, the porous structure of diatomite appears to be a crucial factor to improve mechanical properties of resin composites.

  6. Sorption of Uranium Ions from Their Aqueous Solution by Resins Containing Nanomagnetite Particles

    Directory of Open Access Journals (Sweden)

    Mahmoud O. Abd El-Magied

    2016-01-01

    Full Text Available Magnetic amine resins composed of nanomagnetite (Fe3O4 core and glycidyl methacrylate (GMA/N,N′-methylenebisacrylamide (MBA shell were prepared by suspension polymerization of glycidyl methacrylate with N,N′-methylenebisacrylamide in the presence of nanomagnetite particles and immobilized with different amine ligands. These resins showed good magnetic properties and could be easily retrieved from their suspensions using an external magnetic field. Adsorption behaviors of uranium ions on the prepared resins were studied. Maximum sorption capacities of uranium ions on R-1 and R-2 were found to be 92 and 158 mg/g. Uranium was extracted successfully from three granite samples collected from Gabal Gattar pluton, North Eastern Desert, Egypt. The studied resins showed good durability and regeneration using HNO3.

  7. Preparation of alkyd resins containing PEG unit and their dispersing effects of inorganic particles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chill Won; Gong, Myoung Seon [Dept. of Chemistry, Dankook University, Cheonan (Korea); Kim, Chang Bae [Dept. of Chemistry, Dankook University, Seoul (Korea)

    2000-02-01

    Poly(ethylene glycol)-containing alkyd resins were prepared for the dispersing agent and binder by reacting the carboxy-terminated poly(ethylene glycol) with 1,1,1-trimethylolpropane monostearate obtained from 1,1,1-trimethylolpropane and stearic acid. Dispersing properties of titanium dioxide and talc were compared by measuring transmittance of the dispersing solutions, and rate of the sedimentation in 1,1,1-trichloroethane. These alkyd resins, which contained both hydrophilic and lipophilic parts, showed a good dispersion of the polar inorganic particles in the non-polar solvent. The dispersing effect of the PEG-containing alkyd resins showed its maximum when the molecular weights of hydrophilic and lipophilic parts were almost the same. This happened when the alkyd resin was prepared from PEG 1000, which turned out to agree well with HLB value 10.25. 10 refs., 5 figs., 2 tabs.

  8. 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.

  9. Microscopic Approaches to Decomposition and Burning Processes of a Micro Plastic Resin Particle under Abrupt Heating

    Science.gov (United States)

    Ohiwa, Norio; Ishino, Yojiro; Yamamoto, Atsunori; Yamakita, Ryuji

    To elucidate the possibility and availability of thermal recycling of waste plastic resin from a basic and microscopic viewpoint, a series of abrupt heating processes of a spherical micro plastic particle having a diameter of about 200 μm is observed, when it is abruptly exposed to hot oxidizing combustion gas. Three ingenious devices are introduced and two typical plastic resins of polyethylene terephthalate and polyethylene are used. In this paper the dependency of internal and external appearances of residual plastic embers on the heating time and the ingredients of plastic resins is optically analyzed, along with appearances of internal micro bubbling, multiple micro explosions and jets, and micro diffusion flames during abrupt heating. Based on temporal variations of the surface area of a micro plastic particle, the apparent burning rate constant is also evaluated and compared with those of well-known volatile liquid fuels.

  10. Source Term Model for Fine Particle Resuspension from Indoor Surfaces

    National Research Council Canada - National Science Library

    Kim, Yoojeong; Gidwani, Ashok; Sippola, Mark; Sohn, Chang W

    2008-01-01

    This Phase I effort developed a source term model for particle resuspension from indoor surfaces to be used as a source term boundary condition for CFD simulation of particle transport and dispersion in a building...

  11. Effect of resin-composite filler particle size and shape on shrinkage-stress.

    Science.gov (United States)

    Satterthwaite, Julian D; Maisuria, Amit; Vogel, Karin; Watts, David C

    2012-06-01

    The aim of this study was to investigate the effect of variations in filler particle size and shape on the polymerization shrinkage-stress kinetics of resin-composites. A model series of 12 VLC resin-composites were studied. The particulate dispersed phase volume fraction was 56.7%: these filler particles were systematically graded in size, and further were either spherical or irregular. A Bioman instrument (cantilever beam method) was employed to determine the shrinkage-stress kinetics following 40s irradiation (600 mW/cm(2)) at 23°C (n=3). All data were captured for 60 min and the final shrinkage-stress calculated. Shrinkage-stress varied between 3.86 MPa (SD 0.14) for S3 (spherical filler particles of 500 nm) and 8.44 MPa (SD 0.41) for I1 (irregular filler particles of 450 nm). The shrinkage-stress values were generally lower for those composites with spherical filler particles than those with irregular filler particles. The differences in shrinkage-stress with filler particle size and shape were statistically significant (pparticles exhibit lower shrinkage-stress values compared to those with irregular filler particles. Shrinkage-stress and shrinkage-stress rate vary in a complex manner with variations in the size of the dispersed phase particles: a hypothesized explanation for the effect of filler particle size and shape is presented. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Fine and ultrafine particles emitted from laser printers as indoor air contaminants in German offices.

    Science.gov (United States)

    Tang, Tao; Hurraß, Julia; Gminski, Richard; Mersch-Sundermann, Volker

    2012-11-01

    Various publications indicate that the operation of laser printers and photocopiers may be associated with health effects due to the release of gaseous components and fine and ultrafine particles (UFP). However, only sparse studies are available that evaluate the possible exposure of office workers to printer emissions under real conditions. Therefore, the aim of our study was to assess the exposure of office workers to particulate matter released from laser printers and photocopiers. Concentrations of fine particles and UFP were measured before, during, and after the operation of laser printing devices in 63 office rooms throughout Germany. Additionally, the particles were characterized by electron microscopy and energy-dispersive X-ray spectroscopy. A significant increase of fine particles and UFP was identified in ambient workplace air during and after the printing processes. Particle fractions between 0.23 and 20 μm emitted by the office machines significantly affect particle mass concentrations while printing 500 pages, i.e., during the printing process, PM(0.23-20), PM(2.5), and PM(10) concentrations increased in 43 out of the evaluated 62 office rooms investigated. Additionally, a significant increase was observed in submicrometer particles, with median particle number concentrations of 6,503 particles/cm(3) before and 18,060 particles/cm(3) during the printing process. Our data indicate that laser printers and photocopiers could be a relevant source of fine particles and particularly UFP in office rooms.

  13. Coupling Solute and Fine Particle Transport with Sand Bed Morphodynamics within a Field Experiment

    Science.gov (United States)

    Phillips, C. B.; Ortiz, C. P.; Schumer, R.; Jerolmack, D. J.; Packman, A. I.

    2017-12-01

    Fine suspended particles are typically considered to pass through streams and rivers as wash load without interacting with the bed, however experiments have demonstrated that hyporheic flow causes advective exchange of fine particles with the stream bed, yielding accumulation of fine particle deposits within the bed. Ultimately, understanding river morphodynamics and ecosystem dynamics requires coupling both fine particle and solute transport with bed morphodynamics. To better understand the coupling between these processes we analyze a novel dataset from a controlled field experiment conducted on Clear Run, a 2nd order sand bed stream located within the North Carolina coastal plain. Data include concentrations of continuously injected conservative solutes and fine particulate tracers measured at various depths within the stream bed, overhead time lapse images of bed forms, stream discharge, and geomorphological surveys of the stream. We use image analysis of bed morphodynamics to assess exchange, retention, and remobilization of solutes and fine particles during constant discharge and a short duration experimental flood. From the images, we extract a time series of bedform elevations and scour depths for the duration of the experiment. The high-resolution timeseries of bed elevation enables us to assess coupling of bed morphodynamics with both the solute and fine particle flux during steady state mobile bedforms prior to the flood and to changing bedforms during the flood. These data allow the application of a stochastic modeling framework relating bed elevation fluctuations to fine particle residence times. This combined experimental and modeling approach ultimately informs our ability to predict not only the fate of fine particulate matter but also associated nutrient and carbon dynamics within streams and rivers.

  14. 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...... capable of transporting the fine particles but introducing the particles through an inclined tube was not possible. After performing some supportive experiments, new version of the experimental set-up, namely four draft tubes pneumatic transport (4-DTPT), was design, constructed and examined. Successful...

  15. Scattering of an ion beam by charged fine particles with Coulomb force

    International Nuclear Information System (INIS)

    Amemiya, H.; Nakamura, Y.

    2002-01-01

    Fine particles satisfying critical limits act as Coulomb forces and scatter charged particles like beams due to the long-range force. Otherwise, fine particles behave as tiny probes. The energy loss and broadening rates of an ion beam by particles having Coulomb fields are investigated where the Coulomb logarithm is taken as a variable. Dependence of the energy loss and broadening on the plasma density, dust charge and beam energy is obtained. A method for measuring the dust surface charge is also given

  16. 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...

  17. 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.

  18. Effect of filler particles morphology of resin-composites on cavity packing force for repeated condensation.

    Science.gov (United States)

    Kaleem, Muhammad; Watts, David C

    2017-05-31

    Effect of variation in morphology and size of filler particles, temperature and increase in condensation speed on packability of resincomposites was investigated. Eight experimental light-cured resin-composites (RZDn series) were tested. Each material was placed in a cylindrical mould at 26 or 32ºC. A flat-ended stainless-steel probe (φ=6 mm) was mechanically lowered with two different speeds 2 and 8 mm/s onto and into at the surface of the unset sample until a compressive force of 1 N was reached. This was repeated for five cycles, and from each cycle F p was calculated. All spherical and irregular filler particle resin-composites showed a decrease in F p with increase in number of compressions. Increase in temperature also decreased F p , but this effect was not very prominent in the case of irregular filler resin-composites. Filler particle morphology, increase in temperature and compression cycle speed has a prominent effect on packability of resin-composites.

  19. 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

  20. Corrosion test on coating systems in the presence of sea-salt fine particles using small specimens

    International Nuclear Information System (INIS)

    Tozawa, Seiichi; Ouchi, Koki; Ito, Akihiko.

    1982-01-01

    A large number of industrial plants and facilities of Japan is often constructed on the seaside area, and so steel materials of these plants and facilities are mostly located under the corrosive environment by sea-salt fine particles. These steel materials are, of course, protected by means of paints, platings or other galvanic protection methods, but some problems to investigate seem still to remain for gaining the better corrosion prevention in such a corrosive environment. In this paper, the results of outdoor atmospheric exposure test by using the small painted specimens are described. The exposure test was practised on the seashore at Tokai Research Establishment of Japan Atomic Energy Research Institute for fourteen months. In this test, it was proved that blasting and control of film thickness could somewhat improve the grade of rust prevention of the exposed specimens, but that melamine-alkyd resin painting systems (total film thickness; 12 -- 36 μm) were generally insufficient for a long time rust prevention system in the presence of sea-salt fine particles. On the other hand, the specimens using zinc rich paint primer or hot dip galvanizing as undercoatings (total film thickness; 173 -- 495 μm) showed the perfect corrosion resistant properties against the corrosive environment of the test site under the influence of sea-salt fine particles. Moreover, even the specimens of the paint films which were artificially scratched in the shape of cross cut got hardly rust on the bare steel area and no deterioration was found on the paint films. (author)

  1. Growth rates of fine aerosol particles at a site near Beijing in June 2013

    Science.gov (United States)

    Zhao, Chuanfeng; Li, Yanan; Zhang, Fang; Sun, Yele; Wang, Pucai

    2018-02-01

    Growth of fine aerosol particles is investigated during the Aerosol-CCN-Cloud Closure Experiment campaign in June 2013 at an urban site near Beijing. Analyses show a high frequency (˜ 50%) of fine aerosol particle growth events, and show that the growth rates range from 2.1 to 6.5 nm h-1 with a mean value of ˜ 5.1 nm h-1. A review of previous studies indicates that at least four mechanisms can affect the growth of fine aerosol particles: vapor condensation, intramodal coagulation, extramodal coagulation, and multi-phase chemical reaction. At the initial stage of fine aerosol particle growth, condensational growth usually plays a major role and coagulation efficiency generally increases with particle sizes. An overview of previous studies shows higher growth rates over megacity, urban and boreal forest regions than over rural and oceanic regions. This is most likely due to the higher condensational vapor, which can cause strong condensational growth of fine aerosol particles. Associated with these multiple factors of influence, there are large uncertainties for the aerosol particle growth rates, even at the same location.

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

    Directory of Open Access Journals (Sweden)

    Wang Leilei

    2008-06-01

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

  3. Analysis of magnetic field orientation process of fine particles using neutron diffraction

    International Nuclear Information System (INIS)

    Terada, Noriki

    2010-01-01

    Fine structures in ceramics are important for enhancing the electrical, thermal, optical and mechanical properties of ceramics. Magnetic field alignment of the crystal orientations of fine particles is one of the most effective methods for controlling fine structures. We used neutron diffraction to investigate magnetic alignment of α-Al 2 O 3 fine particles. In situ neutron diffraction measurements of the suspension were performed to investigate the effect of applying a magnetic field. The results revealed that the balance between the magnetic anisotropy energy and thermal fluctuations is critical in determining the crystal orientations of the α-Al 2 O 3 particles in the suspension. Samples were produced by systematically varying the sintering temperature. They were used for neutron diffraction measurements to investigate the effect of sintering. We found that the crystal orientation improves dramatically at temperatures above the grain growth temperature. In this review, we present the experimental details of the neutron diffraction measurements and analyze the results. (author)

  4. Fine particle and gaseous emissions from normal and smouldering wood combustion in a conventional masonry heater

    Science.gov (United States)

    Tissari, J.; Lyyränen, J.; Hytönen, K.; Sippula, O.; Tapper, U.; Frey, A.; Saarnio, K.; Pennanen, A. S.; Hillamo, R.; Salonen, R. O.; Hirvonen, M.-R.; Jokiniemi, J.

    The fine particle and gas emissions from the residential wood combustion (RWC) appear to be a major contributor to winter-time pollution in Europe. In this study, we characterised the effect of two different combustion conditions on particulate and gaseous emissions from a conventional masonry heater. Normal combustion (NC) is the best available operational practice for the heater, whereas smouldering combustion (SC) mimicked slow heating combustion. It was found that the operational practice in RWC can significantly influence the quantity and quality of particle and gaseous emissions into the atmosphere. In SC, the emissions of carbon monoxide were 3.5-fold, total volatile organics 14-fold and PM 1 6-fold to those of NC, whereas the mass of the inorganic compounds ("fine ash") and particle number emissions were lower from SC than from NC. According to electron microscopy analyses, the observed fine ash particles seemed to occur mainly as separate spherical or irregularly shaped particles but not as agglomerates. Ultrafine (<100 nm) fine ash particles were composed mainly of K, S and Zn, but also in a lesser extent of C, Ca, Fe, Mg, Cl, P and Na. Large agglomerates were found to contain mainly carbon and are considered to be primarily soot particles. The larger spherical and irregularly shaped particles were composed of same alkali metal compounds as ultrafine particles, but they were probably covered with heavy organic compounds. From SC, particles were composed mainly of carbon compounds and they had a more closed structure than the particles from NC, due to organic matter on the particles. In the present experiments, the ultrafine mode in the particle number distributions seemed to be determined mainly by the amount of released ash forming material in combustion, and the shifting of particle size during different combustion conditions seemed to be determined by the amount of condensed organic vapour in the flue gas.

  5. 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

  6. The coercive force of fine particles of monoclinic pyrrhotite (Fe7S8 ...

    African Journals Online (AJOL)

    The temperature dependence of coercive force (Hc) between 77 K and 600 K has been investigated for fine particles of monoclinic pyrrhotite (Fe7S8) of < 1 mm and 1- 30 mm particle sizes. The study has shown that Hc is strongly dependent on temperature, as temperature rises above room temperature (293 K) to near the ...

  7. 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.

  8. 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 -)"

  9. Construction of Fine Particles Source Spectrum Bank in Typical Region and Empirical Research of Matching Diagnosis

    Science.gov (United States)

    Wang, Xing; Sun, Wenliang; Guo, Min; Li, Minjiao; Li, Wan

    2018-01-01

    The research object of this paper is fine particles in typical region. The construction of component spectrum bank is based on the technology of online source apportionment, then the result of the apportionment is utilized to verify the effectiveness of fine particles component spectrum bank and which also act as the matching basis of online source apportionment receptor sample. On the next, the particle source of air pollution is carried through the matching diagnosis empirical research by utilizing online source apportionment technology, to provide technical support for the cause analysis and treatment of heavy pollution weather.

  10. Chemical characterzation of fine particle emissions from the fireplace combustion of woods grown in the Southern United States.

    Science.gov (United States)

    Fine, Philip M; Cass, Glen R; Simoneit, Bernd R T

    2002-04-01

    The fireplace combustion of wood is a significant and largely unregulated source of fine particle pollution in the United States. Source apportionment techniques that use particulate organic compounds as tracers have been successful in determining the contribution of wood smoke to ambient fine particle levels in specific areas in California. To apply these techniques to the rest of the United States, the differences in emissions profiles between different wood smoke sources and fuel types should be resolved. To this end, a series of fireplace source tests was conducted on six fuel wood species found in the Southern United States to determine fine particulate emission factors for total mass, ionic and elemental species, elemental and organic carbon, and over 250 individual organic compounds. The wood species tested, chosen for their high abundance and availability in the Southern U.S. region, were yellow poplar, white ash, sweetgum, mockernut hickory, loblolly pine, and slash pine. The differences in the emissions of compounds such as substituted phenols and resin acids help to distinguish between the smoke from hardwood and softwood combustion. Levoglucosan, a cellulose pyrolysis product which may serve as a tracer for wood smoke in general, was quantified in the emissions from all the wood species burned. The furofuran lignan, yangambin, which was emitted in significant quantities from yellow poplar combustion and not detected in any of the other North American wood smokes, is a potential species-specific molecular tracer which may be useful in qualitatively identifying particulate emissions from a specific geographical area where yellow poplar is being burned.

  11. Evaluation of migration of cesium-137 adsorbed on fine soil particles through natural aerated soil layer

    International Nuclear Information System (INIS)

    Ogawa, Hiromichi; Takebe, Shinichi; Yamamoto, Tadatoshi

    1991-01-01

    In order to evaluate migration of 137 Cs adsorbed on fine soil particles in natural aerated soil layers, filtration constants of fine soil particles between soil and pore water were determined by the inverse analysis of the results of a large scale indoor migration test (STEM) using the soil layer samples collected from the natural aerated soil layers of Tokai and Rokkasho-mura without any disturbance. The amounts of 137 Cs which migrated through the soil layer samples with the movement of fine soil particles were also determined by the inverse analysis. The filtration constant for a loamy soil layer was larger than that for a sandy soil layer and the dependence of the filtration constant on mean diameter was the same as that obtained in small scale column experiments. On the other hand, the amount of 137 Cs which migrated through the soil layer sample with the movement of fine soil particles was 0.15∼6.5% of introduced 137 Cs and dependent on size distribution and solidification degree of the soil layer sample. Therefore, it seems that the amount of 137 Cs which migrates to a long distance with the movement of fine soil particles is small in the case of a fine and solidified soil layer. A trial evaluation of the migration of 137 Cs adsorbed on fine soil particles using the result of the analysis showed that the concentration decreasing effect of Rokkasho's soil layer including the loamy soil layer was larger than that of Tokai's sandy soil layer. (author)

  12. Physical and mechanical properties of bio-composites from wood particles and liquefied wood resin

    Science.gov (United States)

    Hui Pan; Todd F. Shupe; Chung-Yun Hse

    2009-01-01

    Compression molded composites were made from wood particles and a liquefied wood/phenol/formaldehyde co-condensed resin. Based on our previous research, a phenol to wood (P/W) ratio of 2/1 was chosen for this study. The two experimental variables selected were: 1) liquefaction temperature (150o and 180oC) and 2) cooking method (atmospheric and sealed). Panels were...

  13. Structural properties of diamond fine particles and clusters prepared by detonation and decomposition of TNT

    Science.gov (United States)

    Saha, D. K.; Koga, K.; Takeo, H.

    1998-03-01

    The thermal parameter B for three different particle sizes of diamond samples (bulk powder 1-4 μm, fine particle 144-195 Å and cluster 55-61 Å) was determined by the grazing incidence X-ray diffraction method. The values of B were found to be in the range 0.50-0.70 Å 2 for particles in the size range 195-55 Å and 0.27 Å 2 for 1-4 μm. All of them are larger than that of diamond bulk. A clear size dependence of B, increasing with decreasing particle size, was found. By analysing X-ray diffraction data at several temperatures the magnitude of B was found to be due to BS (static part) instead of BT (dynamic part). The average BS values obtained were 0.04 Å 2, 0.19 Å 2 and 0.27 Å 2 for bulk powder, fine particle and cluster samples respectively. Ultrahigh resolution transmission electron microscope (TEM) observation confirmed the presence of strain, distortion, roughness and dislocation lines in many particles. TEM images of particles indicate that the clusters were not spherical in shape; they were mostly cubiform and some were truncated prism-like polyhedral. The present study reveals that the BS component is responsible for the large B value in diamond fine particles and clusters. No clear surface local atomic distortion was found in the particles.

  14. Deposition and fine particle production during dynamic flow in a dry powder inhaler: a CFD approach.

    Science.gov (United States)

    Milenkovic, J; Alexopoulos, A H; Kiparissides, C

    2014-01-30

    In this work the dynamic flow as well as the particle motion and deposition in a commercial dry powder inhaler, DPI (i.e., Turbuhaler) is described using computational fluid dynamics, CFD. The dynamic flow model presented here is an extension of a steady flow model previously described in Milenkovic et al. (2013). The model integrates CFD simulations for dynamic flow, an Eulerian-fluid/Lagrangian-particle description of particle motion as well as a particle/wall interaction model providing the sticking efficiency of particles colliding with the DPI walls. The dynamic flow is imposed by a time varying outlet pressure and the particle injections into the DPI are assumed to occur instantaneously and follow a prescribed particle size distribution, PSD. The total particle deposition and the production of fine particles in the DPI are determined for different peak inspiratory flow rates, PIFR, flow increase rates, FIR, and particle injection times. The simulation results for particle deposition are found to agree well with available experimental data for different values of PIFR and FIR. The predicted values of fine particle fraction are in agreement with available experimental results when the mean size of the injected PSD is taken to depend on the PIFR. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. The mechanical properties of nanofilled resin-based composites: characterizing discrete filler particles and agglomerates using a micromanipulation technique.

    LENUS (Irish Health Repository)

    Curtis, Andrew R

    2009-02-01

    To assess the mechanical properties of discrete filler particles representative of several inorganic fillers in modern dental resin-based composites (RBCs) and to assess the validity of a novel micromanipulation technique.

  16. 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

  17. Durability of Mortar Made with Fine Glass Powdered Particles

    Directory of Open Access Journals (Sweden)

    Rosemary Bom Conselho Sales

    2017-01-01

    Full Text Available Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

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

    International Nuclear Information System (INIS)

    Nino-Martinez, N; Martinez-Castanon, G A; Aragon-Pina, A; Martinez-Gutierrez, F; Martinez-Mendoza, J R; Ruiz, Facundo

    2008-01-01

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO 2 particles using a simple aqueous reduction method. The reducing agent used was NaBH 4 ; different molar ratios TiO 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 2 particles and that the TiO 2 :Ag molar ratio plays an important role. We used three different TiO 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 2 particles

  19. Voltage-Induced Nonlinear Conduction Properties of Epoxy Resin/Micron-Silver Particles Composites

    Science.gov (United States)

    Qu, Zhaoming; Lu, Pin; Yuan, Yang; Wang, Qingguo

    2018-01-01

    The nonlinear conduction properties of epoxy resin (ER)/micron-silver particles (MP) composites were investigated. Under sufficient high intensity applied constant voltage, the obvious nonlinear conduction properties of the samples with volume fraction 25% were found. With increments in the voltage, the conductive switching effect was observed. The nonlinear conduction mechanism of the ER/MP composites under high applied voltages could be attributed to the electrical current conducted via discrete paths of conductive particles induced by the electric field. The test results show that the ER/MP composites with nonlinear conduction properties are of great potential application in electromagnetic protection of electron devices and systems.

  20. Effect of Home Bleaching on Microleakage of Fiber-reinforced and Particle-filled Composite Resins

    Directory of Open Access Journals (Sweden)

    Farahnaz Sharafeddin

    2013-12-01

    Full Text Available Background and aims. Bleaching may exert some negative effects on existing composite resin restorations. The aim of this study was to evaluate the effect of home bleaching on microleakage of fiber-reinforced and particle-filled composite resins. Materials and methods. Ninety class V cavities (1.5×2×3 mm were prepared on the buccal surfaces of 90 bovine teeth. The teeth were randomly divided into 6 groups (n=15 and restored as follows: Groups 1 and 2 with Z100, groups 3 and 4 with Z250, and groups 5 and 6 with Nulite F composite resins. All the specimens were thermocycled. Groups 1, 3 and 5 were selected as control groups (without bleaching and the experimental groups 2, 4 and 6 were bleached with 22% carbamide peroxide gel. All the samples were immersed in 2% basic fuchsin dye for 24 hours and then sectioned longitudinally. Dye penetration was evaluated under a stereomicroscope (×25, at both the gingival and incisal margins. Data were analyzed using Kruskal-Wallis, Mann-Whitney and Wilcoxon tests (α=0.05. Results. Statistical analyses revealed that bleaching gel increased microleakage only at gingival margins with Z250 (P=0.007. Moreover, the control groups showed a statistically significant difference in microleakage at their gingival margins. Nulite F had the maximum microleakage while Z250 showed the minimum (P=0.006. Conclusion. Microleakage of home-bleached restorations might be related to the type of composite resin used.

  1. 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.

  2. 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...

  3. Micromagnetic simulation of thermally activated switching in fine particles

    International Nuclear Information System (INIS)

    Scholz, Werner; Schrefl, Thomas; Fidler, J.

    2001-01-01

    Effects of thermal activation are included in micromagnetic simulations by adding a random thermal field to the effective magnetic field. As a result, the Landau-Lifshitz equation is converted into a stochastic differential equation of Langevin type with multiplicative noise. The Stratonovich interpretation of the stochastic Landau-Lifshitz equation leads to the correct thermal equilibrium properties. The proper generalization of Taylor expansions to stochastic calculus gives suitable time integration schemes. For a single rigid magnetic moment the thermal equilibrium properties are investigated. It is found, that the Heun scheme is a good compromise between numerical stability and computational complexity. Small cubic and spherical ferromagnetic particles are studied

  4. Study of reduction permeability for deposit of fine particles and bacteria in porous media

    International Nuclear Information System (INIS)

    Restrepo Restrepo, Dora Patricia; Cardona Bernal, Felipe Andres; Usta Diaz, Martha Lucia

    2004-01-01

    This work shows a theoretical and practical description of the main variables and physical principles that lead to the obstruction by fine particles and therefore a reduction in permeability for unconsolidated porous media with almost a length foot. The results were also adjusted to theoretical model for the obstruction by fine particles in the entrance face. A first study about bacteria plugging was also carried out in order to try to understand it when these bacteria are in the water of injection of a normal process of water flooding

  5. Elemental analysis of airborne fine particles collected at the roadside of an arterial road

    International Nuclear Information System (INIS)

    Hirabayashi, M.

    2008-01-01

    Airborne particulate matter was collected at the intersection of Industrial Road in Kawasaki-city, Kanagawa, Japan using a 12-stage low-pressure impactor. High concentrations of airborne particulate matter have been observed in this area. The collected samples were analyzed for 34 elements by instrumental neutron activation analysis (INAA), and data on the elemental concentrations were obtained. High concentrations of fine particles of As, Br, Sb, V, and Zn were observed. It was further observed that these fine particles were originated predominantly from the wear of tires and brakes, and not from automobile exhaust emissions. (author)

  6. Synthesis and characterization of fine and monodisperse silver particles of uniform shape

    Science.gov (United States)

    Ducamp-Sanguesa, C.; Herrera-Urbina, R.; Figlarz, M.

    1992-10-01

    Fine silver particles of uniform size and shape have been synthesized from silver nitrate in hot ethylene glycol. Quasi-spheric and monodisperse silver particles are produced only when particle sintering is prevented during the growth step. For this purpose, a protective agent, namely, polyvinylpirrolidone (PVP), was added to the system. Particle size increases with increasing temperature and PVP/silver nitrate weight ratio. Heterogeneous nucleation of metallic silver with a critical concentration of in-situ formed platinum nuclei produces monosize particles that have a rod-like shape. This drastic change in particle shape indicates that under these conditions PVP also acts as a crystal habit modifier. The thickness of rod-like particles changes when different PVP/silver nitrate weight ratios are used. Electron microscopy and X-ray diffraction techniques were used for particle characterization. The synthesis of metallic particles in liquid polyols, which act as both solvent and reducing agent, is a useful method for producing highly pure, fine, and monodisperse particles of uniform shape.

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

    International Nuclear Information System (INIS)

    Mata-Zamora, M.E.; Montiel, H.; Alvarez, G.; Saniger, J.M.; Zamorano, R.; Valenzuela, R.

    2007-01-01

    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 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 M ) and the absorption hysteresis loops (A LFS ). The dependence of these areas as a function of crystallite size is remarkably similar in both experiments

  8. Investigation of fine chalk dust particles' chemical compositions and toxicities on alveolar macrophages in vitro.

    Science.gov (United States)

    Zhang, Yuexia; Yang, Zhenhua; Li, Ruijin; Geng, Hong; Dong, Chuan

    2015-02-01

    The aim of the study is to investigate chemical compositions of fine chalk dust particles (chalk PM2.5) and examine their adverse effects on alveolar macrophages (AMs) in vitro. Morphologies and element concentrations of individual chalk particles were analyzed by using the quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA). The oxidative response of AMs and the potential to generate nitric oxide (NO) by luminol-dependent chemiluminescence (CL) and nitrate reductase method were assessed 4h following the treatment of AMs with differing dosages of fine chalk particles, respectively. Oxidative stress and cytotoxicity elicited by chalk PM2.5 were also examined. The results showed that fine chalk particles were mainly composed of gypsum, calcite, dolomite and a little amount of organic adhesives. Exposure to chalk PM2.5 at 100 μg mL(-1) or 300 μg mL(-1) significantly increased intracellular catalase, malondialdehyde, and NO levels and decreased superoxide dismutase level in AMs, leading to leakage of lactate dehydrogenase (LDH) and reduction of the cell viability. Furthermore, luminol-dependent CL from respiratory burst in AMs was enhanced. It was suggested that chalk PM2.5 could make oxidative damages on AMs and result in cytotoxicity, being likely attributed to excessive reactive oxygen species or reactive nitrogen species induced by mixture of fine gypsum and calcite/dolomite particles. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-03-01

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

  10. Research into fine powder and large particle tyre pyrolysis.

    Science.gov (United States)

    Gao, Ningbo; Li, Aimin; Li, Wanjing

    2009-05-01

    This paper investigates the kinetics of the pyrolysis of scrap tyre using thermogravimetry and a small batch laboratory-scale externally heated fixed-bed. Five particle sizes (20-40, 40-60, 60-80, 80-100, 100-200 mesh) and five heating rates (5, 10, 15, 20, 40 K min(-1)) were investigated. The results show that there is no obvious distinction on weight loss for different sizes. With increasing heating rate the weight loss regions shift to a higher temperature range and the weight loss rate increases. The activation energy (E) and pre-exponential factor constant (A) were calculated using the Arrhenius type kinetic model. The heat value of pyrolysis gases is in the range of 12 to 22 MJ Nm(-3). The yields of solid, liquid and gas of pyrolysis scrap tyre and tyre cube at 800 degrees C were investigated, the ratio of pyrolysis production composition of scrap tyre and tyre cube for gas, oil and char is found to be 35 : 23 : 42 and 10 : 31 : 59, respectively.

  11. 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

  12. [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.

  13. [Emission characteristics of fine particles from grate firing boilers].

    Science.gov (United States)

    Wang, Shu-Xiao; Zhao, Xiu-Juan; Li, Xing-Hua; Wei, Wei; Hao, Ji-Ming

    2009-04-15

    Grate firing boilers are the main type of Chinese industrial boilers, which accounts for 85% of the industrial boilers and is one of the most important emission sources of primary air pollutants in China. In this study, five boilers in three cities were selected and tested to measure the emission characteristics of PM2.5, and gaseous pollutants were applied by a compact dilution sampling system, which was developed for this field study. Results showed that particles mass size distributions for the five industrial boilers presented single peak or double peak, former peaks near 0.14 microm and the later peaks after 1.0 microm; the cyclone dust remover and wet scrubber dust remover had effective removal efficiencies not only to PM2.5, but also to PM1.0; and under the condition of same control techniques, grate firing boiler with high capacity has less PM2.5 emission than the boiler with low capacity. In the PM2.5 collected from flue gases, SO4(2-) was the most abundant ion, accounted for 20%-40% of the PM2.5; and C was the most abundant element (7.5%-31.8%), followed by S (8.4%-18.7%). Carbon balance method was applied to calculate the emission factors of these pollutants. The emission factors of PM2.5, NO, and SO2 were in the range of 0.046-0.486 g x kg(-1), 1.63-2.47 g x kg(-1), 1.35-9.95 g x kg(-1) respectively. The results are useful for the emission inventory development of industrial boilers and the source analysis of PM2.5 in atmospheric environment.

  14. Risk of pneumonia in obstructive lung disease: A real-life study comparing extra-fine and fine-particle inhaled corticosteroids.

    Science.gov (United States)

    Sonnappa, Samatha; Martin, Richard; Israel, Elliot; Postma, Dirkje; van Aalderen, Wim; Burden, Annie; Usmani, Omar S; Price, David B

    2017-01-01

    Regular use of inhaled corticosteroids (ICS) in patients with obstructive lung diseases has been associated with a higher risk of pneumonia, particularly in COPD. The risk of pneumonia has not been previously evaluated in relation to ICS particle size and dose used. Historical cohort, UK database study of 23,013 patients with obstructive lung disease aged 12-80 years prescribed extra-fine or fine-particle ICS. The endpoints assessed during the outcome year were diagnosis of pneumonia, acute exacerbations and acute respiratory events in relation to ICS dose. To determine the association between ICS particle size, dose and risk of pneumonia in unmatched and matched treatment groups, logistic and conditional logistic regression models were used. 14788 patients were stepped-up to fine-particle ICS and 8225 to extra-fine ICS. On unmatched analysis, patients stepping-up to extra-fine ICS were significantly less likely to be coded for pneumonia (adjusted odds ratio [aOR] 0.60; 95% CI 0.37, 0.97]); experience acute exacerbations (adjusted risk ratio [aRR] 0.91; 95%CI 0.85, 0.97); and acute respiratory events (aRR 0.90; 95%CI 0.86, 0.94) compared with patients stepping-up to fine-particle ICS. Patients prescribed daily ICS doses in excess of 700 mcg (fluticasone propionate equivalent) had a significantly higher risk of pneumonia (OR [95%CI] 2.38 [1.17, 4.83]) compared with patients prescribed lower doses, irrespective of particle size. These findings suggest that patients with obstructive lung disease on extra-fine particle ICS have a lower risk of pneumonia than those on fine-particle ICS, with those receiving higher ICS doses being at a greater risk.

  15. 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–...

  16. 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

  17. Hydrodynamic studies of the flow of fine particles through a fluidized dense bed of coarse solids

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, J.

    1993-12-31

    This study explains the hydrodynamics of a circulating fluidized bed (CFB) system, the Battelle Multi-Solids Fluidized Bed System (MSFB). It consists of a circulating fluidized bed of fine particles superimposed on a bubbling bed of coarse solids. One way to characterize such a system is to describe the mechanism of gas-solid flow through the bed. The gas flow in systems like these is through bubbles or slugs (regions of voids containing little or no solids). Bubbles are typically characterized by their size (length or diameter), their rise velocity, and their frequency. Another task of the initial phase of this study is to characterize an L-valve, a solids-recirculating device commonly used in an MSFB. Next, the mechanism of fine particle movement through a bubbling region of coarse fluidized solids is studied in considerable detail. Bubble characteristics are studied in a variety of systems of coarse particles with fines passing through at high velocity. Amongst numerous optical, electrical and other techniques available for the study of the passage of bubbles, the pressure fluctuation technique is the most robust. In this investigation, pressure probes are connected to pressure transducers which are in turn linked to an on-line data acquisition system supported on a microcomputer. A commercially available software package (Notebook) is used to sample pressure at specified points in the fluidized bed at extremely fast rates, of up to 200 Hz. This resulted in pressure-time traces which are analysed to give bubble length, bubble rise velocity, and bubble frequency. Another important objective of this study is to estimate the fine particle residence time in the dense bed section. A defluidization technique is utilized in experimentally measuring the solids holdup in the dense bed. A mathematical model is developed from first principles, based on a momentum balance on the fine particles.

  18. Electron density modification in ionospheric E layer by inserting fine dust particles

    International Nuclear Information System (INIS)

    Misra, Shikha; Mishra, S. K.

    2015-01-01

    In this paper, we have developed the kinetics of E-region ionospheric plasma comprising of fine dust grains and shown that the electron density in E-layer can purposely be reduced/enhanced up to desired level by inserting fine dust particles of appropriate physical/material properties; this may certainly be promising for preferred rf-signal processing through these layers. The analytical formulation is based on average charge theory and includes the number and energy balance of the plasma constituents along with charge balance over dust particles. The effect of varying number density, work function, and photo-efficiency of dust particles on ionospheric plasma density at different altitude in E-layer has been critically examined and presented graphically

  19. Identifying sources of atmospheric fine particles in Havana City using Positive Matrix Factorization technique

    International Nuclear Information System (INIS)

    Pinnera, I.; Perez, G.; Ramos, M.; Guibert, R.; Aldape, F.; Flores M, J.; Martinez, M.; Molina, E.; Fernandez, A.

    2011-01-01

    In previous study a set of samples of fine and coarse airborne particulate matter collected in a urban area of Havana City were analyzed by Particle-Induced X-ray Emission (PIXE) technique. The concentrations of 14 elements (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb) were consistently determined in both particle sizes. The analytical database provided by PIXE was statistically analyzed in order to determine the local pollution sources. The Positive Matrix Factorization (PMF) technique was applied to fine particle data in order to identify possible pollution sources. These sources were further verified by enrichment factor (EF) calculation. A general discussion about these results is presented in this work. (Author)

  20. 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

  1. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Fine particle retention within stream storage areas at base flow and in response to a storm event

    Science.gov (United States)

    Drummond, J. D.; Larsen, L. G.; González-Pinzón, R.; Packman, A. I.; Harvey, J. W.

    2017-07-01

    Fine particles (1-100 µm), including particulate organic carbon (POC) and fine sediment, influence stream ecological functioning because they may contain or have a high affinity to sorb nitrogen and phosphorus. These particles are immobilized within stream storage areas, especially hyporheic sediments and benthic biofilms. However, fine particles are also known to remobilize under all flow conditions. This combination of downstream transport and transient retention, influenced by stream geomorphology, controls the distribution of residence times over which fine particles influence stream ecosystems. The main objective of this study was to quantify immobilization and remobilization rates of fine particles in a third-order sand-and-gravel bed stream (Difficult Run, Virginia, USA) within different geomorphic units of the stream (i.e., pool, lateral cavity, and thalweg). During our field injection experiment, a thunderstorm-driven spate allowed us to observe fine particle dynamics during both base flow and in response to increased flow. Solute and fine particles were measured within stream surface waters, pore waters, sediment cores, and biofilms on cobbles. Measurements were taken at four different subsurface locations with varying geomorphology and at multiple depths. Approximately 68% of injected fine particles were retained during base flow until the onset of the spate. Retention was evident even after the spate, with 15.4% of the fine particles deposited during base flow still retained within benthic biofilms on cobbles and 14.9% within hyporheic sediment after the spate. Thus, through the combination of short-term remobilization and long-term retention, fine particles can serve as sources of carbon and nutrients to downstream ecosystems over a range of time scales.

  3. Fine-tuning in GGM and the 126 GeV Higgs particle

    Science.gov (United States)

    Lalak, Zygmunt; Lewicki, Marek

    2013-05-01

    In this paper we reanalyze the issue of fine-tuning in supersymmetric models which feature Generalized Gauge Mediation (GGM) in the light of recent measurement of the mass of the light Higgs particle and taking into account available data on the value of the muon magnetic moment {g_{μ }}-2 . We consider GGM models with 3, 5 and 6 input parameters and reduce the fine-tuning by assuming simple relations between them at the high scale. We are able to find solutions which give the correct value of the light Higgs mass and are less fine-tuned than models with standard gauge mediation (and with gravity mediation), however one never finds fine-tung measure lower than about 102 if one neglects the data on {g_{μ }}-2 and and about four times more if one takes the constraint given by {g_{μ }}-2 into account. In general the current {g_{μ }}-2 data push the models towards the high fine-tuning region. It is interesting to note, that once one removes the contributions to the finetuning induced by μ and B μ , then in the case with neglected {g_{μ }}-2 constraint one can easily find realistic vacua with fine-tuning of order 1 or lower, while the fine-tung remains always large when the {g_{μ }}-2 constraint is enforced. One should note, that in the last case even a small shift of the light Higgs mass towards smaller values both reduces fine-tuning and helps to improve agreement of a model with {g_{μ }}-2 data.

  4. Effect of Silver Nano-particles on Tensile Strength of Acrylic Resins.

    Science.gov (United States)

    Ghaffari, Tahereh; Hamedi-Rad, Fahimeh

    2015-01-01

    Background and aims. Polymethyl methacrylate (PMMA) is widely used for the fabrication of removable prostheses. Silver nano-particles (AgNps) have been added to PMMA because of their antimicrobial properties, but their effect on the mechanical properties of PMMA is unknown. The aim of this study was to investigate the effects of AgNps on the tensile strength of PMMA. Materials and methods. For this study, 12 specimens were prepared and divided into two groups. Group 1 included PMMA without AgNps and group 2 included PMMA mixed with 5 wt% of AgNps. Tensile strength of the specimens was measured by Zwick Z100 apparatus. Statistical analysis was carried out by SPSS using t-test. Statistical significance was defined at Pparticles. Within the limitations of this study, tensile strength of acrylic resin specimens was influenced by silver nano-particles.

  5. 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.

  6. 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...

  7. Urban cyclist exposure to fine particle pollution in a rapidly growing city

    Science.gov (United States)

    Luce, B. W.; Barrett, T. E.; Ponette-González, A.

    2017-12-01

    Urban cyclists are exposed to elevated atmospheric concentrations of fine particulate matter (particles pollution. Recent research indicates that common exposure hotspots include traffic signals, junctions, bus stations, parking lots, and inclined streets. To identify these and other hotspots, a bicycle equipped with a low-cost, portable, battery-powered particle counter (Dylos 1700) coupled with a Trimble Geo 5T handheld Global Positioning System (GPS; ≤1 m ± resolution) will be used to map and measure particle mass concentrations along predetermined routes. Measurements will be conducted during a consecutive four-month period (Sep-Dec) during morning and evening rush hours when PM2.5 levels are generally highest, as well as during non-rush hour times to determine background concentrations. PM2.5 concentrations will be calculated from particle counts using an equation developed by Steinle et al. (2015). In addition, traffic counts will be conducted along the routes coinciding with the mobile monitoring times. We will present results on identified "hotspots" of high fine particle concentrations and PM2.5 exposure in the City of Denton, where particle pollution puts urban commuters most at risk, as well as average traffic counts from monitoring times. These data can be used to determine pollution mitigation strategies in rapidly growing urban areas.

  8. Synthesis and study of properties of dental resin composites with different nanosilica particles size.

    Science.gov (United States)

    Karabela, Maria M; Sideridou, Irini D

    2011-08-01

    The aim of this work was the synthesis of light-cured resin nanocomposites using nanosilica particles with different particle size and the study of some physical-mechanical properties of the composites. Various types of silica nanoparticles (Aerosil) with average particle size of 40, 20, 16, 14, and 7 nm, used as filler were silanized with the silane 3-methacryloxypropyl-trimethoxysilane (MPS). The total amount of silane used was kept constant at 10 wt% relative to the filler weight to ensure the complete silanization of nanoparticles. The silanizated silica nanoparticles were identified by FT-IR spectroscopy and thermogravimetric analysis (TGA). Then the silanized nanoparticles (55 wt%) were mixed with a photoactivated Bis-GMA/TEGDMA (50/50 wt/wt) matrix. Degree of conversion of composites was determined by FT-IR analysis. The static flexural strength and flexural modulus were measured using a three-point bending set up. The dynamic thermomechanical properties were determined by dynamic mechanical analyzer (DMA). Sorption, solubility and volumetric change were determined after storage of composites in water or ethanol/water solution 75 vol% for 30 days. The TGA for composites was performed in nitrogen atmosphere from 30 to 700 °C. As the average silica particle size decreases, the percentage amount of MPS attached on the silica surface increases. However, the number of MPS molecules attached on the silica surface area of 1 nm(2) is independent of filler particle size. As the average filler particles size decreases a progressive increase in the degree of conversion of composites and an increase in the amount of sorbed water is observed. The prepared composites containing different amount of silica filler, with different particle size, but with the same amount of silanized silica and organic matrix showed similar flexural strength and flexural modulus, except composite with the lowest filler particle size, which showed lower flexural modulus. Copyright © 2011

  9. [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

  10. Method for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

    2008-12-09

    A resin recycling method that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The method includes receiving the resin in container form. The containers are then ground into resin particles. The particles are exposed to a solvent, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. After separating the particles and the resin, a solvent removing agent is used to remove any residual solvent remaining on the resin particles after separation.

  11. Source apportionment of urban fine particle number concentration during summertime in Beijing

    Science.gov (United States)

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

    2014-10-01

    Continuous particle number size distributions (15 nm-2.5 μm), particle chemical compositions, gaseous species and meteorological variables were collected at an urban site in Beijing to investigate the source apportionment of ambient fine particle number concentrations. Hourly data sets were analyzed using the positive matrix factorisation (PMF) which identified a total of eight factors: two traffic factors, two combustion factors, secondary nitrate factors, secondary sulfate + secondary organic aerosol (SOA), fugitive dust and regionally transported aerosol. Traffic (47.9%) and combustion (29.7%) aerosol were found to dominate the particle number concentrations, whereas the most important sources for particle volume concentrations were found to be regionally transported aerosol (30.9%) and combustions (30.1%). Although the diurnal pattern of each of the two traffic factors closely followed traffic rush hour for Beijing, their size modes were different suggesting that these factors might represent local and remote emissions. Biomass burning and coal-fired power plant aerosol were distinguished according to their size modes and chemical species associated with them. Secondary compounds showed similar bimodal particle number size distribution, the distinct diurnal pattern distinguished these factors as secondary nitrate and mixed source of secondary sulfate and SOA. Regionally transported material was characterized by accumulation mode particles. Overall, the introduction of combinations of particle number size distributions and chemical composition data in PMF model is successful at separating the components and quantifying relative contributions to the particle number and volume size distributions in the complex urban atmosphere.

  12. Characterization, optical properties and laser ablation behavior of epoxy resin coatings reinforced with high reflectivity ceramic particles

    Science.gov (United States)

    Li, Wenzhi; Kong, Jing; Wu, Taotao; Gao, Lihong; Ma, Zhuang; Liu, Yanbo; Wang, Fuchi; Wei, Chenghua; Wang, Lijun

    2018-04-01

    Thermal damage induced by high power energy, especially high power laser, significantly affects the lifetime and performance of equipment. High-reflectance coating/film has attracted considerable attention due to its good performance in the damage protection. Preparing a high-reflectance coating with high reaction endothermal enthalpy will effectively consume a large amount of incident energy and in turn protect the substrate from thermal damage. In this study, a low temperature process was used to prepare coatings onto substrate with complex shape and avoid thermal effect during molding. An advanced high reflection ceramic powder, La1‑xSrxTiO3+δ , was added in the epoxy adhesive matrix to improve the reflectivity of coating. The optical properties and laser ablation behaviors of coatings with different ceramic additive ratio of La1‑xSrxTiO3+δ and modified epoxy-La1‑xSrxTiO3+δ with ammonium polyphosphate coatings were investigated, respectively. We found that the reflectivity of coatings is extremely high due to mixed high-reflection La1‑xSrxTiO3+δ particles, up to 96% at 1070 nm, which can significantly improve the laser resistance. In addition, the ammonium polyphosphate modifies the residual carbon structure of epoxy resin from discontinuous fine particles structure to continuous and porous structure, which greatly enhances the thermal-insulation property of coating. Furthermore, the laser ablation threshold is improved obviously, which is from 800 W cm‑2 to 1000 W cm‑2.

  13. 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...... represents the changes in flow rate over time through the device than the constant flow rate usually applied with an impactor alone. The aerosol cloud was released before the peak inspiratory effort had been achieved and accordingly the early part and not the peak of the inspiratory performance...... 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...

  14. 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.

  15. Indoor fine particles: the role of terpene emissions from consumer products.

    Science.gov (United States)

    Sarwar, Golam; Olson, David A; Corsi, Richard L; Weschler, Charles J

    2004-03-01

    Consumer products can emit significant quantities of terpenes, which can react with ozone (O3). Resulting byproducts include compounds with low vapor pressures that contribute to the growth of secondary organic aerosols (SOAs). The focus of this study was to evaluate the potential for SOA growth, in the presence of O3, following the use of a lime-scented liquid air freshener, a pine-scented solid air freshener, a lemon-scented general-purpose cleaner, a wood floor cleaner, and a perfume. Two chamber experiments were performed for each of these five terpene-containing agents, one at an elevated O3 concentration and-the other at a lower O3 concentration. Particle number and mass concentrations increased and O3 concentrations decreased during each experiment. Experiments with terpene-based air fresheners produced the highest increases in particle number and mass concentrations. The results of this study clearly demonstrate that homogeneous reactions between O3 and terpenes from various consumer products can lead to increases in fine particle mass concentrations when these products are used indoors. Particle increases can occur during periods of elevated outdoor O3 concentrations or indoor O3 generation, coupled with elevated terpene releases. Human exposure to fine particles can be reduced by minimizing indoor terpene concentrations or O3 concentrations.

  16. Using portable particle sizing instrumentation to rapidly measure the penetration of fine and ultrafine particles in unoccupied residences.

    Science.gov (United States)

    Zhao, H; Stephens, B

    2017-01-01

    Much of human exposure to particulate matter of outdoor origin occurs inside buildings, particularly in residences. The particle penetration factor through leaks in a building's exterior enclosure assembly is a key parameter that governs the infiltration of outdoor particles. However, experimental data for size-resolved particle penetration factors in real buildings, as well as penetration factors for fine particles less than 2.5 μm (PM 2.5 ) and ultrafine particles less than 100 nm (UFPs), remain limited, in part because of previous limitations in instrumentation and experimental methods. Here, we report on the development and application of a modified test method that utilizes portable particle sizing instrumentation to measure size-resolved infiltration factors and envelope penetration factors for 0.01-2.5 μm particles, which are then used to estimate penetration factors for integral measures of UFPs and PM 2.5 . Eleven replicate measurements were made in an unoccupied apartment unit in Chicago, IL to evaluate the accuracy and repeatability of the test procedure and solution methods. Mean estimates of size-resolved penetration factors ranged from 0.41 ± 0.14 to 0.73 ± 0.05 across the range of measured particle sizes, while mean estimates of penetration factors for integral measures of UFPs and PM 2.5 were 0.67 ± 0.05 and 0.73 ± 0.05, respectively. Average relative uncertainties for all particle sizes/classes were less than 20%. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Production of hydroxyl radicals from Fe-containing fine particles in Guangzhou, China

    Science.gov (United States)

    Ma, Shexia; Ren, Ke; Liu, Xiaowen; Chen, Laiguo; Li, Mei; Li, Xiaoying; Yang, Jian; Huang, Bo; Zheng, Mei; Xu, Zhencheng

    2015-12-01

    Reactive oxygen species (ROS) production from ambient fine particles has been correlated with the soluble transition metal content of PM2.5, which also has clear association with particle-mediated cardiopulmonary toxicity. Hydroxyl radical (rad OH) is the most harmful ROS species through chemical reactions of redox-active particle components. Atmospheric Fe, as the dominant species of the transition metals in the atmosphere, is associated with rad OH generation in ambient particle extracts. Our results revealed that Fe-containing particles (18,730 in total number) contributed approximately 3.7% on average to all detected particles throughout the summer and winter sampling period in Guangzhou, which was clustered into four distinct particle classes, including Fe-rich, Metal-rich, NaK-rich and Dust-rich. Fe-rich class was the dominant one with a fraction of 61%, followed by Dust-rich (14%), Metal-rich (13%). and NaK-rich (12%). The iron oxide was enriched in the Fe-rich class. rad OH generation induced by Fe-containing fine particles collected in Guangzhou (GZ) was quantified in a surrogate lung fluid (SLF), and it was found that Fe-containing fine particles were generally much reactive in generating rad OH in the presence of four antioxidants (200 μM ascorbate, 300 μM citrate, 100 μM reduced L-glutathione, and 100 μM uric acid). The annual average rad OH amount produced in our samples was 132.98 ± 27.43 nmol rad OH mg-1 PM2.5. rad OH production had a clear seasonal pattern with higher amount in summer and lower in winter. By measuring the amount of total and SLF-soluble metal in our PM2.5 samples using ICP-MS, we found that ROS activities were associated with the ionizable Fe through Fenton type reactions in the Guangzhou PM2.5. Expected burdens of PM2.5 derived rad OH in human lung lining fluid suggests that typical daily particulate matter exposure in Guangzhou is already a concern, and it could produce much higher levels of rad OH, leading to higher

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

    Science.gov (United States)

    Jang, Min; Lee, Hyun-Ju; Shim, Yonsik

    2010-04-01

    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 microm, 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(-1) FL-2949 (coagulant) and 12 mg L(-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.

  20. Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

    International Nuclear Information System (INIS)

    Understanding of the emissions of coarse (PM 10 ≤10 μm), fine (PM 2.5 ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5–10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

  1. XRF-analysis of fine and ultrafine particles emitted from laser printing devices.

    Science.gov (United States)

    Barthel, Mathias; Pedan, Vasilisa; Hahn, Oliver; Rothhardt, Monika; Bresch, Harald; Jann, Oliver; Seeger, Stefan

    2011-09-15

    In this work, the elemental composition of fine and ultrafine particles emitted by ten different laser printing devices (LPD) is examined. The particle number concentration time series was measured as well as the particle size distributions. In parallel, emitted particles were size-selectively sampled with a cascade impactor and subsequently analyzed by the means of XRF. In order to identify potential sources for the aerosol's elemental composition, materials involved in the printing process such as toner, paper, and structural components of the printer were also analyzed. While the majority of particle emissions from laser printers are known to consist of recondensated semi volatile organic compounds, elemental analysis identifies Si, S, Cl, Ca, Ti, Cr, and Fe as well as traces of Ni and Zn in different size fractions of the aerosols. These elements can mainly be assigned to contributions from toner and paper. The detection of elements that are likely to be present in inorganic compounds is in good agreement with the measurement of nonvolatile particles. Quantitative measurements of solid particles at 400 °C resulted in residues of 1.6 × 10(9) and 1.5 × 10(10) particles per print job, representing fractions of 0.2% and 1.9% of the total number of emitted particles at room temperature. In combination with the XRF results it is concluded that solid inorganic particles contribute to LPD emissions in measurable quantities. Furthermore, for the first time Br was detected in significant concentrations in the aerosol emitted from two LPD. The analysis of several possible sources identified the plastic housings of the fuser units as main sources due to substantial Br concentrations related to brominated flame retardants.

  2. Joint Effect of Particle Charge and Adsorbable Foreign Gases on Vapor Condensation on Fine Aerosol Particles

    Czech Academy of Sciences Publication Activity Database

    Levdansky, V.V.; Smolík, Jiří; Moravec, Pavel

    2008-01-01

    Roč. 35, č. 10 (2008), s. 1246-1248 ISSN 0735-1933 R&D Projects: GA AV ČR(CZ) IAA400720804 Institutional research plan: CEZ:AV0Z40720504 Keywords : charged particle * adsorption * condensation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.332, year: 2008

  3. Effect of silver nano particles on flexural strength of acrylic resins.

    Science.gov (United States)

    Sodagar, Ahmad; Kassaee, Mohammad Zaman; Akhavan, Azam; Javadi, Negar; Arab, Sepideh; Kharazifard, Mohammad Javad

    2012-04-01

    Poly(methyl methacrylate), PMMA, is widely used for fabrication of removable orthodontic appliances. Silver nano particles (AgNps) have been added to PMMA because of their antimicrobial properties. The aim of this study is to investigate the effect of AgNps on the flexural strength of PMMA. Acrylic liquid containing 0.05% and 0.2% AgNps was prepared for two kinds of acrylic resins: Rapid Repair &Selecta Plus. Two groups without AgNps were used as control groups. For each one, flexural strength was investigated via Three Point Bending method for the 15 acrylic blocks. Two-way ANOVA, one way ANOVA and Tukey tests were used for statistical analysis. Rapid Repair without AgNps showed the highest flexural strength. Addition of 0.05% AgNps to Rapid Repair, significantly decreased its flexural strength while, continuing the addition up to 0.2% increased it nearly up to its primary level. In contrast, addition of AgNps to Selecta Plus increased its flexural strength but addition of 0.05% nano particles was more effective than 0.2%. The effect of AgNps on flexural strength of PMMA depends on several factors including the type of acrylics and the concentrations of nano particles. Copyright © 2011 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  4. Effect of Silver Nano-particles on Tensile Strength of Acrylic Resins

    Directory of Open Access Journals (Sweden)

    Tahereh Ghaffari

    2015-03-01

    Full Text Available Background and aims. Polymethyl methacrylate (PMMA is widely used for the fabrication of removable prostheses. Silver nano-particles (AgNps have been added to PMMA because of their antimicrobial properties, but their effect on the mechanical properties of PMMA is unknown. Theaim of this study was to investigate the effects of AgNps on the tensile strength of PMMA. Materials and methods. For this study, 12 specimens were prepared and divided into two groups. Group 1 included PMMA without AgNps and group 2 included PMMA mixed with 5 wt% of AgNps. Tensile strength of the specimens was measured by Zwick Z100 apparatus. Statistical analysis was carried out by SPSS using t-test. Statistical significance was defined at P<0.05. Results. This study showed that the mean tensile strengthof PMMA in group 2 was significantly lower than that in group 1. Therefore, the tensile strength decreased significantly after incorporation of silver nano-particles. Conclusion. Within the limitations of this study, tensile strength of acrylic resin specimens was influenced by silver nano-particles.

  5. Sampling and single particle analysis for the chemical characterisation of fine atmospheric particulates: A review.

    Science.gov (United States)

    Elmes, Michele; Gasparon, Massimo

    2017-11-01

    To better understand the potential environmental and human health impacts of fine airborne particulate matter (APM), detailed physical and chemical characterisation is required. The only means to accurately distinguish between the multiple compositions in APM is by single particle analysis. A variety of methods and instruments are available, which range from filter-based sample collection for off-line laboratory analysis to on-line instruments that detect the airborne particles and generate size distribution and chemical data in real time. There are many reasons for sampling particulates in the ambient atmosphere and as a consequence, different measurement strategies and sampling devices are used depending on the scientific objectives and subsequent analytical techniques. This review is designed as a guide to some of the techniques available for the sampling and subsequent chemical analysis of individual inorganic particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Source apportionment of ultrafine and fine particle concentrations in Brisbane, Australia.

    Science.gov (United States)

    Friend, Adrian J; Ayoko, Godwin A; Jayaratne, E Rohan; Jamriska, Milan; Hopke, Philip K; Morawska, Lidia

    2011-08-01

    To investigate the significance of sources around measurement sites, assist the development of control strategies for the important sources and mitigate the adverse effects of air pollution due to particle size. In this study, sampling was conducted at two sites located in urban/industrial and residential areas situated at roadsides along the Brisbane Urban Corridor. Ultrafine and fine particle measurements obtained at the two sites in June-July 2002 were analysed by positive matrix factorization. Six sources were present, including local traffic, two traffic sources, biomass burning and two currently unidentified sources. Secondary particles had a significant impact at site 1, while nitrates, peak traffic hours and main roads located close to the source also affected the results for both sites. This significant traffic corridor exemplifies the type of sources present in heavily trafficked locations and future attempts to control pollution in this type of environment could focus on the sources that were identified.

  8. Acoustic agglomeration of fine particles based on a high intensity acoustical resonator

    Science.gov (United States)

    Zhao, Yun; Zeng, Xinwu; Tian, Zhangfu

    2015-10-01

    Acoustic agglomeration (AA) is considered to be a promising method for reducing the air pollution caused by fine aerosol particles. Removal efficiency and energy consuming are primary parameters and generally have a conflict with each other for the industry applications. It was proved that removal efficiency is increased with sound intensity and optimal frequency is presented for certain polydisperse aerosol. As a result, a high efficiency and low energy cost removal system was constructed using acoustical resonance. High intensity standing wave is generated by a tube system with abrupt section driven by four loudspeakers. Numerical model of the tube system was built base on the finite element method, and the resonance condition and SPL increase were confirmd. Extensive tests were carried out to investigate the acoustic field in the agglomeration chamber. Removal efficiency of fine particles was tested by the comparison of filter paper mass and particle size distribution at different operating conditions including sound pressure level (SPL), and frequency. The experimental study has demonstrated that agglomeration increases with sound pressure level. Sound pressure level in the agglomeration chamber is between 145 dB and 165 dB from 500 Hz to 2 kHz. The resonance frequency can be predicted with the quarter tube theory. Sound pressure level gain of more than 10 dB is gained at resonance frequency. With the help of high intensity sound waves, fine particles are reduced greatly, and the AA effect is enhanced at high SPL condition. The optimal frequency is 1.1kHz for aerosol generated by coal ash. In the resonace tube, higher resonance frequencies are not the integral multiplies of the first one. As a result, Strong nonlinearity is avoided by the dissonant characteristic and shock wave is not found in the testing results. The mechanism and testing system can be used effectively in industrial processes in the future.

  9. Investigations of fine particles concentrations in the atmospheric air near highways

    Directory of Open Access Journals (Sweden)

    T.S. Ulanova

    2016-12-01

    Full Text Available This paper presents the results of the experimental determination of particulate matter PM 2,5 , PM 10 mass concentration and total suspended particles up to 15 microns (TSP, which are the priority components of air pollutants near the highways. The measurements were made during the year 2016 using a laser analyzer of aerosol DustTrak 8533. The study shows the dependence of the particulate matter concentration from the time of day and the traffic congestion. The sampling (N = 67 was performed due to brief program on the basis of the route monitoring station, which is located on the road junction with heavy traffic – up to1,200 vehicles per hour on the test sites. The single concentrations of the suspended substances reached the levels of the Maximum permissible concentration (MPC of 1.5. During the study period, the exceeding of the established average daily MPC for fine particles PM 2.5 and PM 10 fractions near the highways have not been identified. The significant linear relationship between the number of diesel vehicles on stops and the concentrations of particulate matter PM 2.5 , PM 10 , TSP (correlation coefficient from 0.62 to 0.65; Fisher's criterion of 14.2 to 38.0; p <0.05 has been established and parameterized, what allows to predict the level of air pollution by diesel vehicles when braking and accelerating. It is recommended to fulfill continuous monitoring of the average daily and single MPC of the fine suspended particles near the roads with traffic load of 769 – 1270 or more the diesel vehicles per every 20 minutes. The obtained data may be used in evaluation of the risk to public health induced by the transport emissions as well as in the estimation of the fine particles PM 2.5 , PM 10 concentrations on the sites close to the highways of the large industrial center.

  10. Thermal Conductivity of Epoxy Resin Composites Filled with Combustion Synthesized h-BN Particles

    Directory of Open Access Journals (Sweden)

    Shyan-Lung Chung

    2016-05-01

    Full Text Available The thermal conductivity of epoxy resin composites filled with combustion-synthesized hexagonal boron nitride (h-BN particles was investigated. The mixing of the composite constituents was carried out by either a dry method (involving no use of solvent for low filler loadings or a solvent method (using acetone as solvent for higher filler loadings. It was found that surface treatment of the h-BN particles using the silane 3-glycidoxypropyltrimethoxysilane (GPTMS increases the thermal conductivity of the resultant composites in a lesser amount compared to the values reported by other studies. This was explained by the fact that the combustion synthesized h-BN particles contain less –OH or active sites on the surface, thus adsorbing less amounts of GPTMS. However, the thermal conductivity of the composites filled with the combustion synthesized h-BN was found to be comparable to that with commercially available h-BN reported in other studies. The thermal conductivity of the composites was found to be higher when larger h-BN particles were used. The thermal conductivity was also found to increase with increasing filler content to a maximum and then begin to decrease with further increases in this content. In addition to the effect of higher porosity at higher filler contents, more horizontally oriented h-BN particles formed at higher filler loadings (perhaps due to pressing during formation of the composites were suggested to be a factor causing this decrease of the thermal conductivity. The measured thermal conductivities were compared to theoretical predictions based on the Nielsen and Lewis theory. The theoretical predictions were found to be lower than the experimental values at low filler contents (< 60 vol % and became increasing higher than the experimental values at high filler contents (> 60 vol %.

  11. Thermal Conductivity of Epoxy Resin Composites Filled with Combustion Synthesized h-BN Particles.

    Science.gov (United States)

    Chung, Shyan-Lung; Lin, Jeng-Shung

    2016-05-20

    The thermal conductivity of epoxy resin composites filled with combustion-synthesized hexagonal boron nitride (h-BN) particles was investigated. The mixing of the composite constituents was carried out by either a dry method (involving no use of solvent) for low filler loadings or a solvent method (using acetone as solvent) for higher filler loadings. It was found that surface treatment of the h-BN particles using the silane 3-glycidoxypropyltrimethoxysilane (GPTMS) increases the thermal conductivity of the resultant composites in a lesser amount compared to the values reported by other studies. This was explained by the fact that the combustion synthesized h-BN particles contain less -OH or active sites on the surface, thus adsorbing less amounts of GPTMS. However, the thermal conductivity of the composites filled with the combustion synthesized h-BN was found to be comparable to that with commercially available h-BN reported in other studies. The thermal conductivity of the composites was found to be higher when larger h-BN particles were used. The thermal conductivity was also found to increase with increasing filler content to a maximum and then begin to decrease with further increases in this content. In addition to the effect of higher porosity at higher filler contents, more horizontally oriented h-BN particles formed at higher filler loadings (perhaps due to pressing during formation of the composites) were suggested to be a factor causing this decrease of the thermal conductivity. The measured thermal conductivities were compared to theoretical predictions based on the Nielsen and Lewis theory. The theoretical predictions were found to be lower than the experimental values at low filler contents ( 60 vol %).

  12. Extended X-ray absorption fine structure investigation of adsorption and separation phenomena of metal ions in organic resin.

    Science.gov (United States)

    Ikeda, Atsushi; Yaita, Tsuyoshi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Suzuki, Shinichi; Suzuki, Tatsuya; Fujii, Yasuhiko

    2007-11-01

    Analytical technique using organic resins has already been well-developed, and its applications are employed in various fields; nevertheless, the chemical phenomena occurring inside the resin remain unclear for the most part. In the present study, we apply EXAFS spectroscopy to elucidate the adsorption and separation phenomena of metal ions by organic resin. That is, the chemical species of trivalent lanthanides (Ln(III)) adsorbed in a tertiary pyridine resin from hydrochloric acid and nitric acid solutions have been determined by EXAFS. The results in HCl solutions suggest that Ln(III) ions are partly dehydrated in the resin phase, enabling the pyridine groups of the resin and chloride ions to coordinate to the Ln(III) ions in their primary coordination sphere. On the other hand, Ln(III) ions are tightly coordinated by several nitrate ions in HNO3 solutions and they keep forming the nitrate complex even in the resin phase. The lighter Ln of Nd tends to form an anionic nitrate complex, [Nd(NO3)4.nH2O]-, in the resin phase, while the middle Ln of Sm exists as a cationic nitrate complex, [Sm(NO3)2.nH2O]+, for the most part. On the basis of these EXAFS results, the adsorption and separation mechanisms of the pyridine resin in HCl solutions are interpreted as the direct coordination of pyridine groups to metal ions, while the mechanisms in HNO3 solutions are mainly dominated by the anion-exchange reaction between the protonated pyridine groups and the anionic nitrate complexes of Ln(III). The obtained results demonstrate that the hydration of metal ions weakens, and instead, other complexations are enhanced in the resin phase.

  13. Contrasting macrophage activation by fine and ultrafine titanium dioxide particles is associated with different uptake mechanisms

    Directory of Open Access Journals (Sweden)

    Schmidt Annette M

    2011-10-01

    Full Text Available Abstract Inhalation of (nanoparticles may lead to pulmonary inflammation. However, the precise mechanisms of particle uptake and generation of inflammatory mediators by alveolar macrophages (AM are still poorly understood. The aim of this study was to investigate the interactions between particles and AM and their associated pro-inflammatory effects in relation to particle size and physico-chemical properties. NR8383 rat lung AM were treated with ultrafine (uf, fine (f TiO2 or fine crystalline silica (DQ12 quartz. Physico-chemical particle properties were investigated by transmission electron microscopy, elemental analysis and thermogravimetry. Aggregation and agglomeration tendency of the particles were determined in assay-specific suspensions by means of dynamic light scattering. All three particle types were rapidly taken up by AM. DQ12 and ufTiO2 , but not fTiO2 , caused increased extracellular reactive oxygen species (ROS, heme oxygenase 1 (HO-1 mRNA expression and tumor necrosis factor (TNF-α release. Inducible nitric oxide synthase (iNOS mRNA expression was increased most strongly by ufTiO2 , while DQ12 exclusively triggered interleukin (IL 1β release. However, oscillations of intracellular calcium concentration and increased intracellular ROS were observed with all three samples. Uptake inhibition experiments with cytochalasin D, chlorpromazine and a Fcγ receptor II (FcγRII antibody revealed that the endocytosis of fTiO2 by the macrophages involves actin-dependent phagocytosis and macropinocytosis as well as clathrin-coated pit formation, whereas the uptake of ufTiO2 was dominated by FcγIIR. The uptake of DQ12 was found to be significantly reduced by all three inhibitors. Our findings suggest that the contrasting AM responses to fTiO2 , ufTiO2 and DQ12 relate to differences in the involvement of specific uptake mechanisms.

  14. Reproducing the optical properties of fine desert dust aerosols using ensembles of simple model particles

    International Nuclear Information System (INIS)

    Kahnert, Michael

    2004-01-01

    Single scattering optical properties are calculated for a proxy of fine dust aerosols at a wavelength of 0.55 μm. Spherical and spheroidal model particles are employed to fit the aerosol optical properties and to retrieve information about the physical parameters characterising the aerosols. It is found that spherical particles are capable of reproducing the scalar optical properties and the forward peak of the phase function of the dust aerosols. The effective size parameter of the aerosol ensemble is retrieved with high accuracy by using spherical model particles. Significant improvements are achieved by using spheroidal model particles. The aerosol phase function and the other diagonal elements of the Stokes scattering matrix can be fitted with high accuracy, whereas the off-diagonal elements are poorly reproduced. More elongated prolate and more flattened oblate spheroids contribute disproportionately strongly to the optimised shape distribution of the model particles and appear to be particularly useful for achieving a good fit of the scattering matrix. However, the clear discrepancies between the shape distribution of the aerosols and the shape distribution of the spheroidal model particles suggest that the possibilities of extracting shape information from optical observations are rather limited

  15. 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

  16. Comparison of fine particle colemanite and boron frit in concrete for time-strength relationship

    International Nuclear Information System (INIS)

    Volkman, D.E.; Bussolini, P.L.

    1992-01-01

    This paper reports that the element boron, when added to concrete, has proved effective in shielding neutron particles by absorbing the neutron and emitting a low-energy gamma ray. The various boron additives used with concrete can severely retard the set time and strength gain. An advantage to using small particle size boron is that the smaller grain size provides better boron disbursement within the concrete matrix to absorb neutrons. However, boron additives of powder consistency are usually not used due to the greater potential of forming chemical solutions that act as a retarder in the concrete. Research has shown that the amount of boron additives in concrete can be reduced significantly if fine grain particles can be successfully incorporated into the concrete matrix. The purpose of this study is to compare strength gain characteristics of concrete mixes containing various quantities of fine grain boron additive. The boron additive colemanite, a natural mineral, is compared with two brands of manufactured aggregate, boron frit. Concrete test cylinders are molded for testing the compressive strength of the mix after 4, 7, 28, and 56 days. Tested are five different quantities of colemanite as well as five comparable amounts of boron frit for each brand of the material. The test values are compared with a control concrete specimen containing no boron additive. Results of this study can be used to optimize the cost and effectiveness of boron additives in radiation shielding concrete

  17. Oxidation and evaporation of sulfur species at atmospheric entry of iron sulfide fine particles

    Science.gov (United States)

    Isobe, H.; Murozono, K.

    2017-12-01

    Micrometeorites have the most abundant flux in current accumulation of planetary materials to the Earth. Micrometeorites are heated and reacted with upper atmosphere at atmospheric entry. Evaporation of meteoritic materials, especially sulfur species, may have environmental effect at upper atmosphere (e.g. Court and Sephton, 2011; Tomkins et al., 2016). Troilite is typical FeS phase in chondritic meteorites. In this study, quick heating and cooling experiments of FeS reagent particles were carried out with a fine particles free falling apparatus with controlled gas flow (Isobe and Gondo, 2013). Starting material reagent is inhomogeneous mixture of troilite, iron oxide and iron metal. Oxygen fugacity was controlled to FMQ +1.5 log unit. Maximum temperature of the particles was higher than 1400°C for approximately 0.5 seconds. Run products with rounded shape and smooth surface show the particles were completely melted. Chemical compositions of particles analyzed on cross sections are generally well homogenized from inhomogeneous starting materials by complete melting. Molar ratios of Fe in melted regions are close to 0.5, while compositions of S and O are various. Varieties of S and O compositions show various degree of oxidation and evaporation of sulfur. Distribution of compositions of melted regions in Fe-S-O system is plotted in liquidus compositions of FeO and FeS saturated melt. Troilite in micrometeorite is melted and oxidized by atmospheric entry. Compositions of FeS melt in fine spherules are following Fe-S-O phase relations even in a few seconds. Molar ratios of Fe in melt are close to 0.5, while compositions of S and O are various. Varieties of S and O compositions show various degree of oxidation and evaporation of sulfur. Evaporation of sulfur from meteoritic materials in atmospheric entry heating may depend on oxygen fugacity of the upper atmosphere. Sulfur supply from meteoritic materials to atmosphere may be limited on planets with oxygen

  18. Magnetic properties of Fe3O4 fine particles: time dependence and Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Ismail, A.; Said, M.; Hamam, Y.; Lehlooh, A.; Abu-aljarayesh, I.

    1996-01-01

    Isothermal remanent magnetizations were carried out two samples of Fe 3 O 4 fine particle systems. The measurements were made at temperatures (Τ), 85≤Τ≤290K, and for time(t), 20≤t≤500s. room temperature Moessbauer spectra were collected for the same systems. The distribution of blocking temperature, average anisotropy constants, the coefficient of magnetic viscosity, and the distribution of hyperfine field values were estimated. The results are analyzed and discussed within the context of Nee'I's theory of superparamagnetism. (authors). 14 refs., 10 figs., tab

  19. Contribution of road traffic to ambient fine particle concentrations (PM{sub 10}) in Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Hueglin, Ch.; Devos, W.; Gehrig, R.; Hofer, P.; Kobler, J. [Swiss Federal Laboratoires for Materials Testing and Research, EMPA, Dubendorf (Switzerland); Stahel, W.A. [Seminar for Statistics, ETH Zurich (Switzerland); Baltensperger, U. [Paul Scherrer Institute, Villigen PSI (Switzerland); Monn, Ch. [Institute for Hygiene and Applied Physiology, ETH Zurich (Switzerland)

    2000-07-01

    A multivariate receptor model was applied to estimate the contribution of road traffic to ambient levels of fine particles (PM{sub 10}) at different locations in Switzerland. At two roadside sites with heavy local traffic, the road traffic was found to account for 46% and 64% of PM{sub 10}. At an urban background site, the estimated average road traffic contribution was 34%, whereas a slightly higher value was obtained at a suburban site (36%). This results are in good agreement with the findings of a recent study, where a conceptually different approach (dispersion modelling) was applied. (authors)

  20. 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...... the settling velocity of a suspension appears in the actual and local mass conservation equation as an apparent settling velocity. A new approach to measuring this variable settling velocity is mentioned and its relation to well-known principles, e.g. settling columns, is discussed....

  1. 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.

  2. [Influences of composition on brush wear of composite resins. Influences of particle size and content of filler].

    Science.gov (United States)

    Yuasa, S

    1990-07-01

    The influences of the composition on abrasion resistance of composite resins were examined using various experimental composite resins which had various matrix resin, filler size and content. The abrasion test was conducted by the experimental toothbrush abrasion testing machine developed in our laboratory. Three series of heat-curing composite resins were tested. One series was made from a Bis-MPEPP or UDMA monomer, and a silica filler with an average particle size of 0.04, 1.9, 3.8, 4.3, 7.5, 13.8 and 14.1 microns. The filler content of this series was constant at 45 wt%. The second series contained a silica filler of 4.3 microns in a content ranging from 35 to 75 wt%. The third series contained a microfiller (0.04 microns) and macrofiller (4.3 microns) in total content of 45 wt%. In this series, the microfiller was gradually replaced by 5, 15, 25 and 45 wt% of the macrofiller. The results obtained for these three series indicated that the abrasion resistance of composite resins was controlled by the inorganic filler, mainly filler size and content. The abrasion loss did not vary with the difference of matrix resin. When the particle size of the filler was below about 5 microns, the abrasion resistance decreased markedly with the decrease in filler size. The composite resin which contained a 0.04 or 1.9 micron filler was less resistant to toothbrush wear than the unfilled matrix resin. However, the microfiller also contributed to abrasion resistance when used in combination with the macrofiller, although abrasion resistance decreased with the increase in the microfiller concentration. The increase of filler content clearly improved the abrasion resistance when used the macrofiller. The analysis of these results and SEM observations of the brushed surfaces of samples suggested that the toothbrush abrasion was three-body abrasion caused by the abrasive in the toothpaste, and affected by the difference in the particle size between abrasive and filler, and between

  3. Coarse and fine particles but nout ultrafine particles in urban air trigger hospital admission for asthma in children

    DEFF Research Database (Denmark)

    Iskander, A.; Andersen, Z.J.; Bønnelykke, K.

    2012-01-01

    .AimTo study whether short-term exposure to air pollution is associated with hospital admissions for asthma in children. It is hypothesised that (1) the association between asthma admissions and air pollution is stronger with UFPs than with coarse (PM(10)) and fine (PM(2.5)) particles, nitrogen oxides (NO...... association was found between hospital admissions for asthma in children aged 0-18 years and NO(x) (OR 1.11; 95% CI 1.05 to 1.17), NO(2) (1.10; 95% CI 1.04 to 1.16), PM(10) (1.07; 95% CI 1.03 to 1.12) and PM(2.5) (1.09; 95% CI 1.04 to 1.13); there was no association with UFPs. The association was stronger...

  4. Fine hematite particles of Martian interest: absorption spectra and optical constants

    International Nuclear Information System (INIS)

    Marra, A C; Blanco, A; Fonti, S; Jurewicz, A; Orofino, V

    2005-01-01

    Hematite is an iron oxide very important for the study of climatic evolution of Mars. It can occur in two forms: red and grey, mainly depending on the granulometry of the samples. Spectra of bright regions of Mars suggest the presence of red hematite particles. Moreover the Thermal Emission Spectrometer (TES), on board the Mars Global Surveyor mission, has discovered a deposit of crystalline grey hematite in Sinus Meridiani. TES spectra of that Martian region exhibit features at about 18, 23 and 33 μm that are consistent with hematite. Coarse grey hematite is considered strong evidence for longstanding water, while it is unknown whether the formation of fine-grained red hematite requires abundant water. Studies are needed in order to further characterize the spectral properties of the two kinds of hematite. For this reason we have analyzed a sample of submicron hematite particles in the 6.25-50 μm range in order to study the influence of particles size and shape on the infrared spectra. The optical constants of a particulate sample have been derived and compared with published data concerning bulk samples of hematite. Our results seem to indicate that particle shape is an important factor to take into account for optical constants derivation

  5. Enhancement of dispersion and adhesion of B4C particles in epoxy resin using direct ultrasonic excitation

    International Nuclear Information System (INIS)

    Jun, Jiheon; Kim, Jaewoo; Bae, Yeonjoo; Seo, Young Soo

    2011-01-01

    Highlights: → Enhanced adhesion and dispersion of B 4 C particles in epoxy resin was achieved. → FTIR spectrum was used for examination of B 4 C adhesion with epoxy resin. → Direct ultrasonic excitation causes enhanced surface treatment of B 4 C. → We developed an epoxy based neutron shield with higher mechanical properties. - Abstract: Enhancement of the mechanical properties of the B 4 C/epoxy composites, which is used as a neutron shield for spent nuclear fuel cask, was achieved by direct ultrasonic dispersion of the B 4 C particles in the hardener using an immersed horn, while those prepared without direct ultrasonic dispersion showed insufficient adhesion as well as some agglomerates in the epoxy resin. Degrees of agglomeration and adhesion were analyzed by means of the SEM images and the FTIR peaks belong to C-C stretching mode of the hardener ring, which was lowered and flattened by van der Waals interaction between the B 4 C particles and the hardener ring substituent. The tensile strength of the B 4 C/epoxy composites prepared by direct ultrasonic dispersion was maintained (or increased) compared to that for the neat epoxy matrix, while those prepared without ultrasonic dispersion were degraded significantly. Consequently, direct ultrasonic dispersion process developed in this investigation could achieve uniform dispersion as well as strong adhesion of the B 4 C particles in/with the epoxy matrix enhancing the material properties without any chemical treatment resulting unwanted impurities.

  6. Thermo-mechanical characterization of siliconized E-glass fiber/hematite particles reinforced epoxy resin hybrid composite

    Energy Technology Data Exchange (ETDEWEB)

    Arun Prakash, V.R., E-mail: vinprakash101@gmail.com; Rajadurai, A., E-mail: rajadurai@annauniv.edu.in

    2016-10-30

    Highlights: • Particles dimension have reduced using Ball milling process. • Importance of surface modification was explored. • Surface modification has been done to improve adhesion of fiber/particles with epoxy. • Mechanical properties has been increased by adding modified fiber and particles. • Thermal properties have been increased. - Abstract: In this present work hybrid polymer (epoxy) matrix composite has been strengthened with surface modified E-glass fiber and iron(III) oxide particles with varying size. The particle sizes of 200 nm and <100 nm has been prepared by high energy ball milling and sol-gel methods respectively. To enhance better dispersion of particles and improve adhesion of fibers and fillers with epoxy matrix surface modification process has been done on both fiber and filler by an amino functional silane 3-Aminopropyltrimethoxysilane (APTMS). Crystalline and functional groups of siliconized iron(III) oxide particles were characterized by XRD and FTIR spectroscopy analysis. Fixed quantity of surface treated 15 vol% E-glass fiber was laid along with 0.5 and 1.0 vol% of iron(III) oxide particles into the matrix to fabricate hybrid composites. The composites were cured by an aliphatic hardener Triethylenetetramine (TETA). Effectiveness of surface modified particles and fibers addition into the resin matrix were revealed by mechanical testing like tensile testing, flexural testing, impact testing, inter laminar shear strength and hardness. Thermal behavior of composites was evaluated by TGA, DSC and thermal conductivity (Lee’s disc). The scanning electron microscopy was employed to found shape and size of iron(III) oxide particles adhesion quality of fiber with epoxy matrix. Good dispersion of fillers in matrix was achieved with surface modifier APTMS. Tensile, flexural, impact and inter laminar shear strength of composites was improved by reinforcing surface modified fiber and filler. Thermal stability of epoxy resin was improved

  7. 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}.

  8. System for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2010-11-23

    A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

  9. Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Hatada, Motoyoshi; Fujita, Iwao; Korekawa, Kei-ichi.

    1994-10-01

    Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO 4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

  10. 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.

  11. 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.

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

    International Nuclear Information System (INIS)

    Cohen, D.

    1996-01-01

    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 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 μg/cm 2 of material which corresponds to about 10μg/m 3 of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5μm. 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

  13. Nanoparticles Decorated on Resin Particles and Their Flame Retardancy Behavior for Polymer Composites

    Directory of Open Access Journals (Sweden)

    Nour F. Attia

    2017-01-01

    Full Text Available New nanocomposites have been developed by doping of amberlite IR120 resin with spherical TiO2 nanoparticles in the presence of maleate diphosphate. Polystyrene composites of resin, maleate diphosphate, and resin-maleate diphosphate were prepared individually. This is in addition to preparation of polymer nanocomposites of polystyrene-resin doped TiO2 nanoparticles-maleate diphosphate. The flame retardancy and thermal stability properties of these developed polymer composites were evaluated. The inclusion of resin and resin doped nanoparticles improved the fire retardant behavior of polystyrene composites and enhanced their thermal stability. Synergistic behavior between flame retardant, resin, and nanoparticles was detected. The rate of burning of the polymer nanocomposites was recorded as 10.7 mm/min achieving 77% reduction compared to pure polystyrene (46.5 mm/min. The peak heat release rate (PHRR of the new polymer composites has reduced achieving 46% reduction compared to blank polymer. The morphology and dispersion of nanoparticles on resin and in polymer nanocomposites were characterized using transmission and scanning electron microscopy, respectively. The flame retardancy and thermal properties were evaluated using UL94 flame chamber, cone tests, and thermogravimetric analysis, respectively.

  14. The effect of particle size on green pellet properties of iron ore fines

    Directory of Open Access Journals (Sweden)

    Satyananda Patra

    2017-01-01

    Full Text Available Recently, the grade of iron ore deposits has deteriorated and further development of low grade deposits is desired. Presently, the most effective and often followed route taken to utilize such deposits is the provision of beneficiation plants for upgrading iron ore and pelletizing plants for agglomerating. The iron ore fines cannot be directly used in the blast furnace as they severely reduce the permeability of the blast furnace bed and bring down the efficiency of the furnace. To overcome this, agglomeration of high grade iron ore fines is done to serve as blast furnace burden. Both the beneficiation and pelletization techniques are key process in utilization of low grade iron ores. This study deals with the beneficiation and agglomeration of the low grade iron ore; up to the extent such that it becomes an ideal blast furnace feed. Effect of particle size on pellet quality during pellet making has also been aimed and studied along with the development of flowsheet for beneficiation of low grade iron ore.

  15. [The dangers to health of fine dust particles in the air].

    Science.gov (United States)

    Brunekreef, B

    2006-04-01

    Many scientific studies have been published that connect all kinds of toxicological characteristics offine dust particles, measured in vitro, with lung damage parameters both in animals and humans. These studies do not provide an unequivocal picture on the mechanisms that are responsible for the perceived connection between exposure to fine dust and the degree of illness and death. Without connecting to specific sources of air pollution, this type of study moreover, is only of limited value for drawing up control policy. Even if one or more responsible properties could be determined, it is still unlikely that these would be translated into a standard for permitted levels of concentration in the open air. It is far more likely that such insight will be used for specific source policy aimed at tackling the sources that contribute the most to the harmfulness of the mixture of air pollution.

  16. 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.

  17. Deposition velocities to Sorbus aria, Acer campestre, Populus deltoides x trichocarpa 'Beaupre', Pinus nigra and x Cupressocyparis leylandii for coarse, fine and ultra-fine particles in the urban environment

    International Nuclear Information System (INIS)

    Freer-Smith, P.H.; Beckett, K.P.; Taylor, Gail

    2005-01-01

    Trees are effective in the capture of particles from urban air to the extent that they can significantly improve urban air quality. As a result of their aerodynamic properties conifers, with their smaller leaves and more complex shoot structures, have been shown to capture larger amounts of particle matter than broadleaved trees. This study focuses on the effects of particle size on the deposition velocity of particles (Vg) to five urban tree species (coniferous and broadleaved) measured at two field sites, one urban and polluted and a second more rural. The larger uptake to conifers is confirmed, and for broadleaves and conifers Vg values are shown to be greater for ultra-fine particles (Dp<1.0 μm) than for fine and coarse particles. This is important since finer particles are more likely to be deposited deep in the alveoli of the human lung causing adverse health effects. The finer particle fraction is also shown to be transported further from the emission source; in this study a busy urban road. In further sets of data the aqueous soluble and insoluble fractions of the ultra-fines were separated, indicating that aqueous insoluble particles made up only a small proportion of the ultra-fines. Much of the ultra-fine fraction is present as aerosol. Chemical analysis of the aqueous soluble fractions of coarse, fine and ultra-fine particles showed the importance of nitrates, chloride and phosphates in all three size categories at the polluted and more rural location

  18. Effect of Adhesion Between Submicron Filler Particles and a Polymeric Matrix on the Structure and Mechanical Properties of Epoxy-Resin-Based Compositions

    Science.gov (United States)

    Bogomolova, O. Yu.; Biktagirova, I. R.; Danilaev, M. P.; Klabukov, M. A.; Polsky, Yu. E.; Pillai, Saju; Tsentsevitsky, A. A.

    2017-03-01

    The structure and mechanical properties of composites based on an ED-20 epoxy resin, modified with ZnO and ZnO particles untreated or encapsulated in polystyrene, were studied. It is shown that the introduction of polystyrene-encapsulated ZnO submicroparticles into the epoxy resin changed its supramolecular structure in comparison with that of the resin filled with untreated ones. It was established that the presence of shell on the filler particles affected the mechanical properties of the polymer composites — their hardness increased by 22.5% and elastic modulus by 13%.

  19. Clinical Evaluation of Indirect Particle-Filled Composite Resin CAD/CAM Partial Crowns after 24 Months.

    Science.gov (United States)

    Zimmermann, Moritz; Koller, Christina; Reymus, Marcel; Mehl, Albert; Hickel, Reinhard

    2017-04-19

    Resin-based CAD/CAM compound materials might be promising for single-tooth restorations. Insufficient clinical data are available for this new material class. The purpose of this study was to describe initial clinical in vivo results for indirect particle-filled composite resin CAD/CAM restorations after 24 months. Indirect particle-filled composite resin restorations were fabricated with a CAD/CAM method (CEREC Bluecam intraoral scanner, CEREC MCXL milling unit) by calibrated dental students. Forty-two partial crown restorations were seated adhesively in 30 patients with caries lesions or insufficient restorations (baseline). Strict inclusion criteria were defined for the patient collective. Follow-up evaluation comprised 40 restorations after 12 months and 33 restorations after 24 months. Evaluation criteria were modified FDI criteria with grades (1) to (5). Rating with FDI criteria (5) was defined as clinical failure. Statistical analysis was performed with Wilcoxon-Test (p CAD/CAM restorations after 12 months was 95.0% with two debondings observed. The cumulative success rate for indirect particle-filled composite resin CAD/CAM restorations after 24 months was 85.7% with two tooth fractures and one debonding. Statistically significant differences were found for baseline and 24-month follow-up evaluation for anatomic form and marginal adaptation criterion examined in respect to FDI criteria guidelines (Wilcoxon-Test, p CAD/CAM restorations having a clinical success rate of 85.7% after 24 months. Adhesive bonding procedures need to be ensured carefully. A longer clinical evaluation period is necessary to draw further conclusions. © 2017 by the American College of Prosthodontists.

  20. The mechanical properties of nanofilled resin-based composites: characterizing discrete filler particles and agglomerates using a micromanipulation technique.

    Science.gov (United States)

    Curtis, Andrew R; Palin, William M; Fleming, Garry J P; Shortall, Adrian C C; Marquis, Peter M

    2009-02-01

    To assess the mechanical properties of discrete filler particles representative of several inorganic fillers in modern dental resin-based composites (RBCs) and to assess the validity of a novel micromanipulation technique. RBCs with microhybrid (Filtek Z250), 'nanohybrid' (Grandio) and 'nanofilled' (Filtek Supreme), filler particle morphologies were investigated. Filler particles were provided by the manufacturer or separated from the unpolymerized resin using a dissolution technique. Filler particles (n=30) were subjected to compression using a micromanipulation technique between a descending glass probe and a glass slide. The number of distinct fractures particles underwent was determined from force/displacement and stress/deformation curves and the force at fracture and pseudo-modulus of stress was calculated. Agglomerated fillers ('nanoclusters') exhibited up to four distinct fractures, while spheroidal and irregular particles underwent either a single fracture or did not fracture following micromanipulation. Z-tests highlighted failure of nanoclusters to be significant compared with spheroidal and irregular particles (P<0.05). The mean force at first fracture of the nanoclusters was greater (1702+/-909 microN) than spheroidal and irregular particles (1389+/-1342 and 1356+/-1093 microN, respectively). Likewise, the initial pseudo-modulus of stress of nanoclusters (797+/-555 MPa) was also greater than spheroidal (587+/-439 MPa) or irregular (552+/-275 MPa) fillers. The validity of employing the micromanipulation technique to determine the mechanical properties of filler particulates was established. The 'nanoclusters' exhibited a greater tendency to multiple fractures compared with conventional fillers and possessed a comparatively higher variability of pseudo-modulus and load prior to and at fracture, which may modify the damage tolerance of the overall RBC system.

  1. 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.

  2. Chemical characteristics of fine particles emitted from different gas cooking methods

    Science.gov (United States)

    See, Siao Wei; Balasubramanian, Rajasekhar

    Gas cooking is an important indoor source of fine particles (PM 2.5). The chemical characteristics of PM 2.5 emitted from different cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying were investigated in a domestic kitchen. Controlled experiments were conducted to measure the mass concentration of PM 2.5 and its chemical constituents (elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), metals and ions) arising from these five cooking methods. To investigate the difference in particle properties of different cooking emissions, the amount and type of food, and the heat setting on the gas stove were kept constant during the entire course of the experiments. Results showed that deep-frying gave rise to the largest amount of PM 2.5 and most chemical components, followed by pan-frying, stir-frying, boiling, and steaming. Oil-based cooking methods released more organic pollutants (OC, PAHs, and organic ions) and metals, while water-based cooking methods accounted for more water-soluble (WS) ions. Their source profiles are also presented and discussed.

  3. Fine and nanometer scaled particle behavior characterization and control for sustainable energy and environmental technology

    Energy Technology Data Exchange (ETDEWEB)

    Hidehiro Kamiya; Mayumi Tsukada; Wuled Lenggoro; Wladyslaw W. Szymanski [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    2008-07-01

    Characterization and control of fine and nanometer scaled particles are essential technological fundamentals for understanding and development of various approaches concerned with sustainable energy and environmental technology, for example, PM10/PM2.5 and nanoparticle emission, clean and high efficiency power generation systems from biomass and solid waste combustion. The standard measuring methods for PM10/PM2.5 and nanoparticle emission behavior from stationary sources, such as coal-fired power plants and waste incinerators, have been discussed in ISO and numerous countries. However, it is difficult to evaluate the actual emission amount and particle size distribution, such as condensable suspended particulate matter, condensable SPM, which is nucleated and grow during cooling and diluting process from flue to atmosphere. High temperature gas cleaning using rigid ceramic filters is an important technology to develop high efficiency power generation system. In this paper, based on the review of background and recent research works of each subject, mass concentration measurement method of PM10/PM2.5 and size distribution of condensable SPM from stationary sources are introduced. Subsequently, research results with focus on ash adhesion behavior characterization and control for the development of dust collection and gas cleaning technology at high temperature conditions in high efficiency power generation systems by coal, biomass and solid waste combustion are presented. 12 refs., 7 figs., 3 tabs.

  4. 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

  5. Size distribution, chemical composition, and hygroscopicity of fine particles emitted from an oil-fired heating plant.

    Science.gov (United States)

    Happonen, Matti; Mylläri, Fanni; Karjalainen, Panu; Frey, Anna; Saarikoski, Sanna; Carbone, Samara; Hillamo, Risto; Pirjola, Liisa; Häyrinen, Anna; Kytömäki, Jorma; Niemi, Jarkko V; Keskinen, Jorma; Rönkkö, Topi

    2013-12-17

    Heavy fuel oil (HFO) is a commonly used fuel in industrial heating and power generation and for large marine vessels. In this study, the fine particle emissions of a 47 MW oil-fired boiler were studied at 30 MW power and with three different fuels. The studied fuels were HFO, water emulsion of HFO, and water emulsion of HFO mixed with light fuel oil (LFO). With all the fuels, the boiler emitted considerable amounts of particles smaller than 200 nm in diameter. Further, these small particles were quite hygroscopic even as fresh and, in the case of HFO+LFO emulsion, the hygroscopic growth of the particles was dependent on particle size. The use of emulsions and the addition of LFO to the fuel had a reducing effect on the hygroscopic growth of particles. The use of emulsions lowered the sulfate content of the smallest particles but did not affect significantly the sulfate content of particles larger than 42 nm and, further, the addition of LFO considerably increased the black carbon content of particulate matter. The results indicate that even the fine particles emitted from HFO based combustion can have a significant effect on cloud formation, visibility, and air quality.

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

    Science.gov (United States)

    Nascimento, Antônio Paula; Santos, Jane Meri; Mill, José Geraldo; Souza, Juliana Bottoni de; Reis, Neyval Costa; Reisen, Valdério Anselmo

    2017-01-12

    To analyze the association between fine particulate matter concentration in the atmosphere and hospital care by acute respiratory diseases in children. 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. 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. 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. Analisar a associação entre a concentração de material particulado fino na atmosfera e atendimento hospitalar por doenças respiratórias agudas em crianças. Estudo ecológico, realizado na Região da Grande Vitória, ES, no inverno (21 de junho a 21 de setembro de 2013) e no verão (21 de dezembro de 2013 a 19 de março de 2014). Foram avaliados dados de contagem diária de atendimentos ambulatoriais e hospitalizações por doenças respiratórias (CID-10) em crianças de zero a 12 anos em três hospitais da Região da Grande Vitoria. Para a coleta de material particulado fino foram utilizados amostradores portáteis de partículas instalados em seis locais na regi

  7. 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

  8. 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.

  9. Preparation of Fine Particles with Improved Solubility Using a Complex Fluidized-Bed Granulator Equipped with a Particle-Sizing Mechanism.

    Science.gov (United States)

    Hosaka, Shouichi; Okamura, Yasufumi; Tokunaga, Yuji

    2016-01-01

    A new type of fluidized-bed granulator equipped with a particle-sizing mechanism was used for the preparation of fine particles that improved the solubility of a poorly water-soluble drug substance. Cefteram pivoxyl (CEF) was selected as a model drug substance, and its solution with a hydrophilic polymer, hydroxypropyl cellulose (HPC-L), was sprayed on granulation grade lactose monohydrate (Lac). Three types of treated particles were prepared under different conditions focused on the spraying air pressure and the amount of HPC-L. When the amount of HPC-L was changed, the size of the obtained particles was similar. However, particle size distribution was dependent on the amount of HPC-L. Its distribution became more homogenous with greater amounts of HPC-L, but the particle size distribution obtained by decreasing the spraying air pressure was not acceptable. By processing CEF with HPC-L using a complex fluidized-bed granulator equipped with a particle-sizing mechanism, the dissolution ratio was elevated by approximately 40% compared to that of unprocessed CEF. Moreover, in the dissolution profile of treated CEF, the initial burst was suppressed, and nearly zero order release was observed up to approximately 60% in the dissolution profile. This technique may represent a method with which to design fine particles of approximately 100 µm in size with a narrow distribution, which can improve the solubility of a drug substance with low solubility.

  10. Fine particle and organic vapor emissions from staged tests of an in-use aircraft engine

    Science.gov (United States)

    Presto, Albert A.; Nguyen, Ngoc T.; Ranjan, Manish; Reeder, Aaron J.; Lipsky, Eric M.; Hennigan, Christopher J.; Miracolo, Marissa A.; Riemer, Daniel D.; Robinson, Allen L.

    2011-07-01

    Staged tests were conducted to measure the particle and vapor emissions from a CFM56-2B1 gas-turbine engine mounted on a KC-135T Stratotanker airframe at different engine loads. Exhaust was sampled using a rake inlet installed 1-m downstream of the engine exit plane of a parked and chocked aircraft and a dilution sampler and portable smog chamber were used to investigate the particulate matter (PM) emissions. Total fine PM mass emissions were highest at low (4%) and high (85%) load and lower at intermediate loads (7% and 30%). PM mass emissions at 4% load are dominated by organics, while at 85% load elemental carbon is dominant. Quantifying the primary organic aerosol (POA) emissions is complicated by substantial filter sampling artifacts. Partitioning experiments reveal that the majority of the POA is semivolatile; for example, the POA emission factor changed by a factor of two when the background organic aerosol concentration was increased from 0.7 to 4 μg m -3. Therefore, one cannot define a single non-volatile PM emission factor for aircraft exhaust. The gas- and particle-phase organic emissions were comprehensively characterized by analyzing canister, sorbent and filter samples with gas-chromatography/mass-spectrometry. Vapor-phase organic emissions are highest at 4% load and decrease with increasing load. Low-volatility organics (less volatile than a C 12n-alkane) contributed 10-20% of the total organic emissions. The low-volatility organic emissions contain signatures of unburned fuel and aircraft lubricating oil but are dominated by an unresolved complex mixture (UCM) of presumably branched and cyclic alkanes. Emissions at all loads contain more low-volatility organic vapors than POA; thus secondary organic aerosol formation in the aging plume will likely exceed POA emissions.

  11. Microleakage of nano-particle-filled resin-modified glass ionomer using atraumatic restorative technique in primary molars.

    Science.gov (United States)

    Wadenya, Rose; Smith, Jennifer; Mante, Francis

    2010-01-01

    This study compared the marginal leakage of nano-particle-filled resin-modified glass ionomer (RMGIC) restorations made using atraumatic restorative technique (ART) and conventional technique. Twenty primary molars with carious dentin on the buccal surfaces were restored with RMGIC using ART. The teeth were thermally cycled, sectioned and stained with methylene blue. Micro-leakage was compared to a second set of teeth restored conventionally. No significant difference (p > 0.05) in leakage was noted between the conventional and ART groups. The authors concluded that ART with RMGIC provides margins that show comparable leakage to conventionally restored primary teeth.

  12. 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.

  13. Characterization of Fine Metal Particles Derived from Shredded WEEE Using a Hyperspectral Image System: Preliminary Results

    Science.gov (United States)

    Candiani, Gabriele; Picone, Nicoletta; Pompilio, Loredana; Pepe, Monica; Colledani, Marcello

    2017-01-01

    Waste of electric and electronic equipment (WEEE) is the fastest-growing waste stream in Europe. The large amount of electric and electronic products introduced every year in the market makes WEEE disposal a relevant problem. On the other hand, the high abundance of key metals included in WEEE has increased the industrial interest in WEEE recycling. However, the high variability of materials used to produce electric and electronic equipment makes key metals’ recovery a complex task: the separation process requires flexible systems, which are not currently implemented in recycling plants. In this context, hyperspectral sensors and imaging systems represent a suitable technology to improve WEEE recycling rates and the quality of the output products. This work introduces the preliminary tests using a hyperspectral system, integrated in an automatic WEEE recycling pilot plant, for the characterization of mixtures of fine particles derived from WEEE shredding. Several combinations of classification algorithms and techniques for signal enhancement of reflectance spectra were implemented and compared. The methodology introduced in this study has shown characterization accuracies greater than 95%. PMID:28505070

  14. The mechanism of hydrogen sulfide adsorption on fine rubber particle media (FRPM).

    Science.gov (United States)

    Wang, Ning; Park, Jaeyoung; Ellis, Timothy G

    2013-09-15

    A commercial rubber waste product, fine rubber particle media (FRPM), was found to adsorb hydrogen sulfide (H₂S) at 0.12 mg H₂S/g FRPM of adsorption capacity. Since FRPM seems to be an attractive alternative to treat H₂S owing to its economic advantages as well as its physicochemical characteristics, several analyses were conducted to investigate fundamental information, surface properties, and breakthrough characteristics of FRPM as adsorbent. The physical properties of FRPM including composition and surface chemistry were investigated to compare its performance with commonly available commercial H₂S adsorbents such as activated carbon and assess the possible adsorption mechanism. The specific surface area of FRPM was less than 1% of activated carbon. FRPM does not have enough surface area supporting a pure physical adsorption of H₂S because it is particulate in nature with limited porosity. The adsorption of FRPM to remove H₂S was complex mechanism and involved a combination of zinc compounds and carbon black. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. 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

  16. Correlation of light transmittance with asthma attack: fine water particles as a possible inducing factor of asthma.

    Science.gov (United States)

    Kanaya, Kazuo; Okamoto, Koji; Shimbo, Shinichiro; Ikeda, Masayuki

    2011-01-01

    It has been postulated that air-borne fine water particles (or mist) can induce asthma attacks in asthmatic children. To date, no attempt has been made to quantify the density of air-borne fine water particles with the aim of relating particle density to the etiology of asthma among children. The aim of this study was to investigate the relation of asthma attack frequency and the particle density evaluated in terms of light transmittance. The density of fine water particles was quantified by measuring reductions in light transmittance at 250, 365 and 580 nm at an outdoor location when the surroundings were in darkness. The measurements were made at distances varying from 1 to 3 m from the light sources and performed every morning and evening for 1 year. Each day was separated into two half-day units [i.e., morning (from midnight to noon) and afternoon (from noon to midnight)]. The number of asthma attacks among 121 enrolled asthmatic children was counted for each unit. A possible correlation between the transmittance reduction and frequency of asthma attacks was assessed. A significant difference was observed in the extent of reduction in light transmittance at 365 nm between the units with asthma attacks and those without attacks. Furthermore, the reduction in the transmittance was more evident when more asthma attacks were recorded among the patients. No difference was detected in the reduction in light transmittance at 250 or 580 nm. These results support the hypothesis that air-borne fine water particles are among the etiological factors that induce asthma attacks in asthmatic children.

  17. 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

    2001-05-04

    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) NO{sub x} 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. To this end we shall use an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. 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 NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined.

  18. Cyanate Ester Resin Modified with Nano-particles for Inclusion in Continuous Fiber Reinforced Composites

    Science.gov (United States)

    2011-02-25

    transition. The impact strength of the fully cured specimens were determined using a Tinius Olsen Charpy impact strength tester. The samples were machined...by swinging the pendulum for 11 half cycles. 2.3 Results and Discussion The effect of CNT loading on the viscosity of BECy resin at 23 oC is

  19. Ultra-fine particles release from hardcopy devices: sources, real-room measurements and efficiency of filter accessories.

    Science.gov (United States)

    Wensing, Michael; Schripp, Tobias; Uhde, Erik; Salthammer, Tunga

    2008-12-15

    The release of ultra-fine particles (UFP, d toner or paper also revealed UFP emissions. On the basis of these results we reasonably doubt the opinion that UFPs primarily originate from the toner. Instead, the high-temperature fuser unit is assumed to be one source for ultra-fine particle emission. UFP release typically follows the flow path of the cooling air which may leave the printer casing at various points (e.g. the paper tray). This limits the usability of the commercial filter systems available because the released particles could leave the printer without passing through the filter. Chamber measurements with various filter systems retrofitted to a laser printer demonstrate different efficiencies of UFP reduction. Complementary experiments were carried out in an office room. Here the decay of the particle concentration after a print job was about ten times slower than in the test chamber. A toxicological assessment of the emitted particles requires that their chemical composition be known. Due to the low mass of the released UFPs chemical analysis needs a prior enrichment on a feasible media. Experiments using electrostatic precipitation showed a flame retardant (tri-xylyl phosphate) whose concentration on the media was dependent on the number of pages printed. Whether this compound was particle-bound could not be determined.

  20. Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation.

    Science.gov (United States)

    Valentini, Fernanda; Moraes, Rafael R; Pereira-Cenci, Tatiana; Boscato, Noéli

    2014-05-01

    This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Copyright © 2014 Wiley Periodicals, Inc.

  1. 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.

  2. Modeling of meteorology, chemistry and aerosol for the 2017 Utah Winter Fine Particle Study

    Science.gov (United States)

    McKeen, S. A.; Angevine, W. M.; McDonald, B.; Ahmadov, R.; Franchin, A.; Middlebrook, A. M.; Fibiger, D. L.; McDuffie, E. E.; Womack, C.; Brown, S. S.; Moravek, A.; Murphy, J. G.; Trainer, M.

    2017-12-01

    The Utah Winter Fine Particle Study (UWFPS-17) field project took place during January and February of 2017 within the populated region of the Great Salt Lake, Utah. The study focused on understanding the meteorology and chemistry associated with high particulate matter (PM) levels often observed near Salt Lake City during stable wintertime conditions. Detailed composition and meteorological observations were taken from the NOAA Twin-Otter aircraft and several surface sites during the study period, and extremely high aerosol conditions were encountered for two cold-pool episodes occurring in the last 2 weeks of January. A clear understanding of the photochemical and aerosol processes leading to these high PM events is still lacking. Here we present high spatiotemporal resolution simulations of meteorology, PM and chemistry over Utah from January 13 to February 1, 2017 using the WRF/Chem photochemical model. Correctly characterizing the meteorology is difficult due to the complex terrain and shallow inversion layers. We discuss the approach and limitations of the simulated meteorology, and evaluate low-level pollutant mixing using vertical profiles from missed airport approaches by the NOAA Twin-Otter performed routinely during each flight. Full photochemical simulations are calculated using NOx, ammonia and VOC emissions from the U.S. EPA NEI-2011 emissions inventory. Comparisons of the observed vertical column amounts of NOx, ammonia, aerosol nitrate and ammonium with model results shows the inventory estimates for ammonia emissions are low by a factor of four and NOx emissions are low by nearly a factor of two. The partitioning of both nitrate and NH3 between gas and particle phase depends strongly on the NH3 and NOx emissions to the model and calculated NOx to nitrate conversion rates. These rates are underestimated by gas-phase chemistry alone, even though surface snow albedo increases photolysis rates by nearly a factor of two. Several additional conversion

  3. Creation of giant two-dimensional crystal of zinc oxide nanodisk by method of single-particle layer of organo-modified inorganic fine particles.

    Science.gov (United States)

    Meng, Qi; Honda, Nanami; Uchida, Saki; Hashimoto, Kazuaki; Shibata, Hirobumi; Fujimori, Atsuhiro

    2015-09-01

    In this study, the formation and structure of a single-particle layer of organo-zinc oxide are investigated using surface-pressure-area (π-A) isotherms, out-of-plane X-ray diffraction (XRD) analysis, and atomic force microscopy (AFM). Further, techniques for achieving the solubilization of inorganic fine particles in general solvents have been proposed, and a single-particle layer has been formed using such an inorganic solution as a "spreading solution" for an interfacial film. Surface modification of ZnO is performed using a long-chain carboxylic acid. Accordingly, a regular arrangement of ZnO can be easily achieved in order to overcome the relatively weak van der Walls interactions between inorganic materials. A condensed Langmuir monolayer of these particles is also formed. A multiparticle layered structure is constructed by the Langmuir-Blodgett (LB) technique. Out-of-plane XRD measurement results for a single-particle layer of organo-ZnO clearly show a sharp peak at 42 Å. This peak is attributed to the distance between ZnO layers. The AFM image of this single-particle layer of organo-ZnO shows a particle assembly with a uniform height of 60 nm. These aggregated particles form large two-dimensional crystals. In other words, a regular periodic structure along the c-axis and a condensed single-particle layer had been fabricated using Langmuir and LB techniques. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2014-02-07

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

  5. Synthesis and characterization of molybdenum/phenolic resin composites binding with aluminum nitride particles for diamond cutters

    Science.gov (United States)

    Lin, Chun-Te; Lee, Hsun-Tsing; Chen, Jem-Kun

    2013-11-01

    Novolac-type bisphenol-F based molybdenum-phenolic resins/silane-modified aluminum nitride (Mo-BPF/m-AlN) composites were successfully prepared. In the preparation process, molybdate reacted with bisphenol-F based phenolic resins (BPF) to form a low cross-linked Mo-BPF with new Mosbnd O bonds which were confirmed by the FTIR and XPS spectra. Simultaneously, a special silane-modified aluminum nitride (m-AlN) was prepared with 3-aminopropyltriethoxysilane (APTES) modifier. Then, this m-AlN was fully mixed with Mo-BPF to form Mo-BPF/m-AlN which can be further cured with hexamethylenetetramine at 200 °C. The structure and characterization of BPF, Mo-BPF and Mo-BPF/m-AlN were determined by using FTIR, DSC, DMA, TGA, SEM, mechanical properties and contact angle measurements. SEM photographs show that m-AlN particles are uniformly distributed in the Mo-BPF/m-AlN composites. Also there are no gaps or void between m-AlN and Mo-BPF phases, which implies a strong physical bonding between the two phases. The glass transition temperature, thermal resistance, flexural strength, and hardness of Mo-BPF are respectively higher than those of BPF. This is due to the presence of Mosbnd O cross-linking bonds in Mo-BPF. When the m-AlN was additionally incorporated into Mo-BPF, the well-dispersed and well-adhered m-AlN can further promote all the above-mentioned properties of the composites. Typically, the glass transition temperature, decomposition temperature at 5% weight loss and flexural strength of Mo-BPF/m-AlN are 245 °C, 428 °C and 82.7 MPa respectively, which are much higher than the corresponding values of 184 °C, 358 °C and 58.2 MPa for BPF. In addition, the hygroscopic nature of BPF can be inhibited by treating with molybdate or incorporating with m-AlN. This is due to that the m-AlN is hydrophobic and Mosbnd O groups in Mo-BPF are more hydrophobic than OH groups in BPF. Furthermore, Mo-BPF/m-AlN was compared with BPF in the performance as a binder for diamond cutting

  6. 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.

  7. Causality test of ambient fine particles and human influenza in Taiwan: Age group-specific disparity and geographic heterogeneity.

    Science.gov (United States)

    Chen, Cathy W S; Hsieh, Ying-Hen; Su, Hung-Chieh; Wu, Jia Jing

    2018-02-01

    Influenza is a major global public health problem, with serious outcomes that can result in hospitalization or even death. We investigate the causal relationship between human influenza cases and air pollution, quantified by ambient fine particles Taipei in the north and cities in southwestern part of Taiwan are strongly affected by ambient fine particles. Moreover, the elderly group is clearly affected in all study sites. Globalization and economic growth have resulted in increased ambient air pollution (including PM 2.5 ) and subsequently substantial public health concerns in the West Pacific region. Minimizing exposure to air pollutants is particularly important for the elderly and susceptible individuals with respiratory diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. 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.

    communication). It appears that the sediment plume created by such a mining system can have long-term effects on organisms in a given ecosystem. Microfaunal composition and abundance in the deep-sea depends on the source of food availability (Theil 1983... the experiment (Parthiban 2000) suggesting sediment resuspension in the near bottom water column and redistri- bution of fine particles. Observations further showed that sand in the DZ settled fast Figure 4. Comparison of silt from pre-, post- and monitoring-1...

  9. 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

    Ultrafine and fine particle formation as a result of chemical reactions between ozone and four different air fresheners and a typical lemon-scented domestic cleaner was studied in a fully furnished, naturally ventilated office. The study showed that under conditions representative of those...... 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Ido, Yasushi, E-mail: ido.yasushi@nitech.ac.jp [Department of Electric and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya (Japan); Nishida, Hitoshi [Department of Electrical and Control Systems Engineering, National Institute of Technology, Toyama College, 13 Hongo-cho, Toyama (Japan); Iwamoto, Yuhiro [Department of Electric and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya (Japan); Yokoyama, Hiroki [KYB Corporation, 2-4-1 Hamamatsu-cho, Minato-ku, Tokyo (Japan)

    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. - Highlights: • Viscous properties of new magnetic functional fluids were studied experimentally. • The new fluids contain spherical magnetic particles and needle-like particles. • Percolation occurs in the fluid of specific mixing ratio of particles without field. • The fluid of the specific mixing ratio behaves like solid without field. • Mixing needle-like particles causes strong yield stress of the fluid in the field.

  11. 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

  12. Characterizing chemical transport of ozone and fine particles in the Great Lakes region

    Science.gov (United States)

    Spak, Scott N.

    This dissertation presents a science framework relevant to evaluating impacts of land use policy scenarios, energy technologies, and climate on urban and regional air quality. Emerging from collaboration with urban planners, this work provides a means for employing atmospheric chemical transport modeling to understand environmental ramifications of long-term, spatially disaggregated changes in population and automobile emissions at the census tract level, and to assess the sensitivity of these changes to densification strategies. Toward these goals, the framework is used to evaluate model skill in resolving contemporary characteristics of ozone (O3) and speciated fine particles (PM2.5) in the Great Lakes region of North America, and to quantitatively explore meteorological processes that bring about observed features of these pollutants in the region. The Great Lakes were chosen due to a population concentrated in sprawling metropolitan areas, consistently high and widespread pollutant burdens, and seasonal effects of the lakes on the atmosphere. In annual simulation at 36 km resolution, the Community Multiscale Air Quality model is evaluated using speciated PM2.5 measurements taken at regulatory monitoring networks orientated to sample urban, rural, and remote areas. Performance relative to ad-hoc regional modeling goals and prior studies is average to excellent for most species throughout the year. Both pollution episodes and seasonality are captured. The Great Lakes affect pollution seasonality: strong winds advect aerosols around the deep marine boundary layer to lower surface PM2.5 in fall and winter, while O3 over the lakes is enhanced throughout the year, driven by temperature in the cool seasons and lake breeze circulation in spring and summer. Simulations confirm observational evidence that rural and small-city sources are responsible for most regional PM2.5. Sensitivities to urban and rural reductions are of comparable magnitude on a percentage basis

  13. Placental circadian pathway methylation and in utero exposure to fine particle air pollution.

    Science.gov (United States)

    Nawrot, Tim S; Saenen, Nelly D; Schenk, Julie; Janssen, Bram G; Motta, Valeria; Tarantini, Letizia; Cox, Bianca; Lefebvre, Wouter; Vanpoucke, Charlotte; Maggioni, Cristina; Bollati, Valentina

    2018-03-07

    In mammals, a central clock maintains the daily rhythm in accordance with the external environment. At the molecular level, the circadian rhythm is maintained by epigenetic regulation of the Circadian pathway. Here, we tested the role of particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM 2.5 ) exposure during gestational life on human placental Circadian pathway methylation, as an important molecular target for healthy development. In 407 newborns, we quantified placental methylation of CpG sites within the promoter regions of the following genes: CLOCK, BMAL1, NPAS2, CRY1-2 and PER1-3 using bisulfite-PCR-pyrosequencing. Daily PM 2.5 exposure levels were estimated for each mother's residence, using a spatiotemporal interpolation model. We applied mixed-effects models to study the methylation status of the Circadian pathway genes and in utero PM 2.5 exposure, while adjusting for a priori chosen covariates. In a multi-gene model, placental Circadian pathway methylation was positively and significantly (p < 0.0001) associated with 3rd trimester PM 2.5 exposure. Consequently, the single-gene models showed relative methylation differences [Log(fold change)] in placental NPAS2 (+0.16; p = 0.001), CRY1 (+0.59; p = 0.0023), PER2 (+0.36; p = 0.0005), and PER3 (+0.42; p = 0.0008) for an IQR increase (8.9 μg/m 3 ) in 3rd trimester PM 2.5 exposure. PM 2.5 air pollution, an environmental risk factor leading to a pro-inflammatory state of the mother and foetus, is associated with the methylation pattern of genes in the Circadian pathway. The observed alterations in the placental CLOCK epigenetic signature might form a relevant molecular mechanism through which fine particle air pollution exposure might affect placental processes and foetal development. Copyright © 2018. Published by Elsevier Ltd.

  14. 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

    2002-02-05

    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) NO{sub x} 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. To this end work is progress using an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. 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 NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. Progress in the Sixth Quarter (January 1, 2002 through March 31, 2002) was slow because of slagging problems in the combustor. These required the combustor to be rebuilt, a job that is not yet complete. A paper describing our results heretofore has been accepted by the Journal Environmental Science and Technology.

  15. 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

    , before the desulfurisation plant, and in the stack. The following sampling techniques are used: scanning mobility particle sizer, low pressure cascade impactor, dichotomous PM2.5 sampler, and total particle filter. The so-called multi-platform method used in this work Proves useful for gaining insight...... are in the PM2.5 range. The emitted particles primarily stern from the coal ash with a minor contribution of particles of entrained, dried-out droplets of scrubber slurry. The large emitted particles are compact, almost-spherical single particles originating from the ash mineral inclusions in the coal...

  16. Evaluation of methods for the physical characterization of the fine particle emissions from two residential wood combustion appliances

    Science.gov (United States)

    Kinsey, John S.; Kariher, Peter H.; Dong, Yuanji

    The fine particle emissions from a U. S. certified non-catalytic wood stove and a zero-clearance fireplace burning Quercus rubra L. (northern red oak) and Pseudotsuga menziesii (Douglas fir) cordwood each at two different moisture levels were determined. Emission testing was performed using both time-integrated and continuous instrumentation for total particle mass, particle number, particle size distribution, and fixed combustion gases using an atmospheric wind tunnel, full-flow laboratory dilution tunnel, and dilution stack sampler with a comparison made between the three dilution systems and two sampling filter types. The total mass emission factors (EFs) for all dilution systems and filter media are extremely variable ranging from fireplace emissions burning wet oak averaged 11 g kg -1. A substantial number of ultrafine particles in the accumulation size range were also observed during all tests as determined by an Electrical Low Pressure Impactor (ELPI) and Scanning Mobility Particle Sizer. The PM-2.5 (particles ≤2.5 μm in aerodynamic diameter) fractions determined from the ELPI electrometer data ranged from 93 to 98% (mass) depending on appliance type as reported previously by Hays et al. (Aerosol Science, 34, 1061, 2003).

  17. Identification of metals into fine particles (PM2.5) during the dry cold season in the Toluca City

    International Nuclear Information System (INIS)

    Martinez P, A. A.; Aldape U, F.

    2008-01-01

    To know the elemental content of fine particles PM 2.5 that can affect people in the Toluca City, such as metals and another, it was made a campaign collection of fine particles during dry-cold ( November 2006-March 2007). The aerosol samples were collected on Teflon filters with an equipment BGI model PQ200 mark authorized by the Environment Protection Agency (EPA), every other day with a time resolution of 24 h. The determination of the elemental composition of the samples was performed by means of the technique Particle Induced X-Ray Emission (PIXE). The results of the analysis showed consistently 13 elements S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, as, throughout the collection period. We calculated the enrich factor that separates the elements of the natural component of the anthropogenic component. The correlation matrix shows the pairs of elements that are contained in the same air mass as Vanadium and Nickel. From the results it is concluded that the sources that gave rise to these particles are the burning of fossil fuels in motor vehicles, lubricants, additives and burning tires wear of automotive vehicles, besides the products used in agricultural activities. (Author)

  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

    , before the desulfurisation plant, and in the stack. The following sampling techniques are used: scanning mobility particle sizer, low pressure cascade impactor, dichotomous PM2.5 sampler, and total particle filter. The so-called multi-platform method used in this work Proves useful for gaining insight...... into the many particle-affecting processes in a power plant. In the boiler the size of particles extends over four decades, from approximately 20 nm to 200 nm, with the largest mass contained in particles in the size range 10-100 mum. Approximately 99.9% of the particles are removed in the electrostatic...... precipitator and the desulfurization scrubber. The mass fraction of submicron particles, i.e., PM1, increases from similar to 0.3% at the exit of the boiler, just before the electrostatic precipitator, to similar to 30% in the aerosol emitted via the stack. In the stack aerosol 50-80% of the particles...

  19. Seasonal variation and volatility of ultra-fine particles in coastal Antarctic troposphere

    Directory of Open Access Journals (Sweden)

    Keiichiro Hara

    2010-12-01

    Full Text Available The Size distribution and volatility of ultrafine aerosol particles were measured at Syowa Station during the 46-47 Japanese Antarctic Research Expeditions. During the summer, most of the ultrafine particles were volatile particles, which were composed of H_2SO_4, CH_3SO_3H and sulfates bi-sulfates. The abundance of non-volatile particles was ~ 20% during the summer, increasing to>90% in winter-spring. Non-volatile particles in winter were dominantly sea-salt particles. Some ultrafine sea-salt particles might be released from sea-ice. When air mass was transported from the free troposphere over the Antarctic continent, the abundance of non-volatile particles dropped to<30% even in winter.

  20. Determination of air exchange rates of rooms and deposition factors for fine particles by means of photoelectric aerosol sensors

    International Nuclear Information System (INIS)

    Skillas, G.; Siegmann, H.C.; Hueglin, Ch.

    1999-01-01

    Indoor and outdoor concentrations or airborne fine particles from internal combustion engines have been measured over periods of 24 h with a time resolution of 10 s. With this time series, the ventilation air exchange rate of different rooms has been computed using a novel approach to the solution of the mass balance equation. A 'mixing time' parameter has been introduced in order to account for the initial non-homogeneous distribution of the pollutants in the rooms. It is demonstrated that this method can be used to determine the impact of health relevant outdoor particles on the indoor particle concentration. This yields information on the protection a building offers against pollutants entering from outdoors. (author)

  1. Reconciling satellite aerosol optical thickness and surface fine particle mass through aerosol liquid water: ALW AND AOT

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thien Khoi V. [Department of Environmental Sciences, Rutgers University, New Brunswick New Jersey USA; Ghate, Virendra P. [Environmental Science Division, Argonne National Laboratory, Argonne Illinois USA; Carlton, Annmarie G. [Department of Chemistry, University of California, Irvine California USA

    2016-11-22

    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 affecting the 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 IMRPOVE sites using measured ion mass concentrations and NARR meteorological data. Our findings suggest ALW provides a plausible explanation for the geographical and seasonal patterns in AOT and can reconcile previously noted discrepancies with surface mass measurements.

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

    Science.gov (United States)

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

    2013-04-01

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

  3. 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.

  4. Table - Impacts of the Proposed Transport Rule on Counties with Monitors Projected to have Ozone and/or Fine Particle Air Quality Problems

    Science.gov (United States)

    This table shows the impacts of the proposed Transport Rule on Counties with Monitors Projected to have Ozone and/or Fine Particle Air Quality Problems, both with and without the Cross-State Air Pollution Rule.

  5. 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.)

  6. Biosynthesis of silver fine particles and particles decorated with nanoparticles using the extract of Illicium verum (star anise) seeds

    Science.gov (United States)

    Luna, Carlos; Chávez, V. H. G.; Barriga-Castro, Enrique Díaz; Núñez, Nuria O.; Mendoza-Reséndez, Raquel

    2015-04-01

    Given the upsurge of new technologies based on nanomaterials, the development of sustainable methods to obtain functional nanostructures has become an imperative task. In this matter, several recent researches have shown that the biodegradable natural antioxidants of several plant extracts can be used simultaneously as reducing and stabilizing agents in the wet chemical synthesis of metallic nanoparticles, opening new opportunities to design greener synthesis. However, the challenge of these new techniques is to produce stable colloidal nanoparticles with controlled particle uniformity, size, shape and aggregation state, in similar manner than the well-established synthetic methods. In the present work, colloidal metallic silver nanoparticles have been synthesized using silver nitrate and extracts of Illicium verum (star anise) seeds at room temperature in a facile one-step procedure. The resulting products were colloidal suspensions of two populations of silver nanoparticles, one of them with particle sizes of few nanometers and the other with particles of tens of nm. Strikingly, the variation of the AgNO3/extract weight ratio in the reaction medium yielded to the variation of the spatial distribution of the nanoparticles: high AgNO3/extract concentration ratios yielded to randomly dispersed particles, whereas for lower AgNO3/extract ratios, the biggest particles appeared coated with the finest nanoparticles. This biosynthesized colloidal system, with controlled particle aggregation states, presents plasmonic and SERS properties with potential applications in molecular sensors and nanophotonic devices.

  7. Effect of titania particles on the microstructure and properties of the epoxy resin coatings on sintered NdFeB permanent magnets

    International Nuclear Information System (INIS)

    Xu, J.L.; Huang, Z.X.; Luo, J.M.; Zhong, Z.C.

    2014-01-01

    The nanometer titania particles enhanced epoxy resin composite coatings were prepared on the sintered NdFeB permanent magnets by cathodic electrophoretic deposition. The effects of titania particle concentrations on the microstructure and properties of the epoxy coatings were investigated by surface and cross-sectional morphologies observation, surface roughness and microhardness measurement, H 2 SO 4 solution immersion test, neutral salt spray test and magnetic properties measurement. The results showed that the thickness of epoxy coatings with and without the titania particles addition was about 40 μm. The titania particles could be uniformly dispersed and embedded in the epoxy matrix if the titania particles concentration was lower than 40 g/l. With increasing titania particle concentrations, the number of the particles embedded in the epoxy matrix increased and the surface roughness and microhardness of the composite coatings increased. At the same time, the weight loss of the coated samples immersed in H 2 SO 4 solution decreased and the neutral salt spray time of the coated samples prolonged. It could be concluded that the titania particles did not change the thickness of the epoxy coatings and did not deteriorate the magnetic properties of NdFeB substrates, but could greatly improve the microhardness and corrosion resistance of the epoxy coatings. - Highlights: • The titania particles enhanced epoxy resin coatings were prepared on sintered NdFeB by cathodic electrophoretic deposition. • The titania particles could be uniformly dispersed and embedded in the epoxy resin matrix. • With increasing titania concentrations, the surface roughness and the microhardness of composite coatings increased. • The addition of titania particles greatly improved the corrosion resistance of the epoxy coatings. • The composition coatings did not deteriorate the magnetic properties of NdFeB substrates

  8. Effect of titania particles on the microstructure and properties of the epoxy resin coatings on sintered NdFeB permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.L., E-mail: jlxu@nchu.edu.cn; Huang, Z.X.; Luo, J.M.; Zhong, Z.C., E-mail: zzhong.2006@yahoo.com.cn

    2014-04-15

    The nanometer titania particles enhanced epoxy resin composite coatings were prepared on the sintered NdFeB permanent magnets by cathodic electrophoretic deposition. The effects of titania particle concentrations on the microstructure and properties of the epoxy coatings were investigated by surface and cross-sectional morphologies observation, surface roughness and microhardness measurement, H{sub 2}SO{sub 4} solution immersion test, neutral salt spray test and magnetic properties measurement. The results showed that the thickness of epoxy coatings with and without the titania particles addition was about 40 μm. The titania particles could be uniformly dispersed and embedded in the epoxy matrix if the titania particles concentration was lower than 40 g/l. With increasing titania particle concentrations, the number of the particles embedded in the epoxy matrix increased and the surface roughness and microhardness of the composite coatings increased. At the same time, the weight loss of the coated samples immersed in H{sub 2}SO{sub 4} solution decreased and the neutral salt spray time of the coated samples prolonged. It could be concluded that the titania particles did not change the thickness of the epoxy coatings and did not deteriorate the magnetic properties of NdFeB substrates, but could greatly improve the microhardness and corrosion resistance of the epoxy coatings. - Highlights: • The titania particles enhanced epoxy resin coatings were prepared on sintered NdFeB by cathodic electrophoretic deposition. • The titania particles could be uniformly dispersed and embedded in the epoxy resin matrix. • With increasing titania concentrations, the surface roughness and the microhardness of composite coatings increased. • The addition of titania particles greatly improved the corrosion resistance of the epoxy coatings. • The composition coatings did not deteriorate the magnetic properties of NdFeB substrates.

  9. Impact Resistance Enhancement by Adding Core-Shell Particle to Epoxy Resin Modified with Hyperbranched Polymer

    Directory of Open Access Journals (Sweden)

    Shuiping Li

    2017-12-01

    Full Text Available A core-shell particle was fabricated by grafting amino-terminated hyperbranched polymer to the surface of silica nanoparticles. The influences of core-shell particle contents on the tensile and impact strength of the epoxy thermosets modified with amino-terminated hyperbranched polymer were discussed in detail. For comparison, core-shell particle was added into the epoxy/polyamide system for toughness improvement. Results from tensile and impact tests are provided. The introduction of core-shell particle into the epoxy/polyamide systems just slightly enhanced the tensile and impact strength. The incorporation of 3 wt % core-shell particle could substantially improve the tensile and impact strength of epoxy/amino-terminated hyperbranched polymer thermosets. Field emission-scanning electron microscope images of the impact fracture surfaces showed that the excellent impact resistance of epoxy/amino-terminated hyperbranched polymer/core-shell particle thermosets may be attributed to the synergistic effect of shearing deformation and crack pinning/propagation, which is induced by the good compatibility between epoxy matrix and core-shell particle in the presence of amino-terminated hyperbranched polymer.

  10. Evaluating the Performance of Iron Nano-particle Resin in Removing Fluoride from Water

    Directory of Open Access Journals (Sweden)

    Amir Hossein Mahvi

    2011-01-01

    Full Text Available Excessive amounts of fluoride in drinking water pose serious health problems. It is, therefore, essential to remove it from drinking water by appropriate water treatment processes down to standard levels for preventing the health risks associated. The aim of this study was to determine the performance of a kind of hybrid sorbent resin in removing fluoride from water. Batch experiments were performed to investigate adsorption isotherms and the effects of experimental parameters such as contact time (5-120 min and pH (3-9. Results revealed that fluoride adsorption rate was initially rapid but continued at a slower rate before it reached equilibrium in 120 min. Optimum fluoride removal was observed at a pH range of 3-5.5. The data obtained from the experiments were fitted with Langmiur model.

  11. Evaluation of fine ceramics raw powders with particle size analyzers having different measuring principle and its problem

    International Nuclear Information System (INIS)

    Hayakawa, Osamu; Nakahira, Kenji; Tsubaki, Junichiro.

    1995-01-01

    Many kinds of analyzers based on various principles have been developed for measuring particle size distribution of fine ceramics powders. But the reproducibility of the results, interchangeability of the models, reliability of the ends of the measured distribution have not been investigated for each principle. In this paper, these important points for particle size analysis were clarified by measuring raw material powders of fine ceramics. (1) in the case of laser diffraction and scattering method, the reproducibility in the same model is good, however, interchangeability of the different models is not so good, especially at the ends of the distribution. Submicron powders having high refractive index show such a tendency remarkably. (2) the photo sedimentation method has some problems to be conquered, especially in measuring submicron powders having high refractive index or flaky shape particles. The reproducibility of X-ray sedimentation method is much better than that of photo sedimentation. (3) the light obscuration and electrical sensing zone methods, show good reproducibility, however, sometime bad interchangeability is affected by calibration and so on. (author)

  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. [Polycyclic aromatic hydrocarbons and soluble organic fraction in fine particles from solid fraction of biodiesel exhaust fumes].

    Science.gov (United States)

    Szewczyńska, Małgorzata; Pośniak, Małgorzata

    2012-01-01

    This paper presents the results of investigations into the distribution of fine particles in the biodiesel exhaust fumes (bio-DEP), as well as into the content of polycyclic aromatic hydrocarbons (PAHs) and soluble organic fraction (SOF) in the study fractions. Samples of biodiesel B20 and B40 exhaust combustion fumes were generated at the model station composed of a diesel engine from Diesel TDI 2007 Volkswagen. Sioutas personal cascade impactor (SPCI) with Teflon filters and low-pressure impactor ELIPI (Dekati Low Pressure Impactor) were used for sampling diesel exhaust fine particles. The analysis of PAHs adsorbed on particulate fractions was performed by high performance liquid chromatography with fluorescence detection (HPLC/FL). For the determination of dry residue soluble organic fraction of biodiesel exhaust particles the gravimetric method was used. The combustion exhaust fumes of 100% ON contained mainly naphthalene, acenaphthalene, fluorene, phenanthrene, fluoranthene, pyrene, benzo(a)anthracene and chrysene, whilst the exhaust of B40-single PAHs of 4 and 5 rings, such as chrysene, benzo(k)fluoranthene, dibenzo (ah)anthracene and benzo(ghi)perylene. The total content of PAHs in diesel exhaust particles averaged 910 ng/m3 for 100% ON and 340 ng/m3 for B40. The concentrations of benzo(a)antarcene were at the levels of 310 ng/m3 (100% ON) and 90 ng/m3 (B40). The investigations indicated that a fraction < 025 microm represents the main component of diesel exhaust particles, regardless of the used fuel. Bioester B 100 commonly added to diesel fuel (ON) causes a reduction of the total particulates emission and thus reduces the amount of toxic substances adsorbed on their surface.

  15. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D

    2007-01-09

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12-inch IX Column and sixteen cycles were completed in the 24-inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in upflow. Also, upflow Simulant Introduction produced an ideal level bed for the twenty cycles completed using upflow Simulant Introduction. Conversely, the three cycles conducted using downflow Simulant Introduction produced an uneven bed surface with erosion around the thermowells. The RF resin bed in both columns showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. Micrographs comparing representative bead samples before and after testing indicated no change in bead

  16. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D

    2006-11-08

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project-Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12 inch IX Column and sixteen cycles were completed in the 24 inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in upflow. Also, upflow Simulant Introduction produced an ideal level bed for the twenty cycles completed using upflow Simulant Introduction. Conversely, the three cycles conducted using downflow Simulant Introduction produced an uneven bed surface with erosion around the thermowells. The RF resin bed in both columns showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. Micrographs comparing representative bead samples before and after testing indicated no change in bead

  17. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    International Nuclear Information System (INIS)

    Adamson, D

    2007-01-01

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project Hanford Tank Waste Treatment and Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12-inch IX Column and sixteen cycles were completed in the 24-inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in upflow. Also, upflow Simulant Introduction produced an ideal level bed for the twenty cycles completed using upflow Simulant Introduction. Conversely, the three cycles conducted using downflow Simulant Introduction produced an uneven bed surface with erosion around the thermowells. The RF resin bed in both columns showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. Micrographs comparing representative bead samples before and after testing indicated no change in bead

  18. Investigation on the effect of mixed rapeseed stalk residues with wood particles, and mixing of melamine and urea formaldehyde resin on properties of manufactured particleboard

    Directory of Open Access Journals (Sweden)

    Behzad Kord

    2016-09-01

    Full Text Available In this study, the possibility of using the rapeseed stalk mixed with industrial wood particles for manufacturing particleboard with target density of 0.7 gr/cm3 was considered. Variable factors such as mixing ratios of rapeseed stalk with industrial wood particles at five mixing levels of (0-100, 25-75, 50-50, 75-25 and 100-0 percent, mixing ratios of melamine resin with urea formaldehyde at three levels of 0-100, 15-85 and 30-70 percent, and kind of board at two levels of homogenate and layer were considered. 10 percent resin based on oven dried weight of particles, 2 percent catalyzer based on oven dried weight of resin, press temperature and time with 170 OC and 7 minute, press pressure and rate with 30 Kg/cm3 and 4.5 mm/min were fixed. Then, the boards were manufactured and the physical and mechanical properties including modulus of rupture, modulus of elasticity, internal bonding, water absorption and thickness swelling were measured according to EN standard. Results indicated that the modulus of rupture, modulus of elasticity, water absorption and thickness swelling of boards increased with increase rapeseed stalk loading; however, the internal bonding decreased. Also, the use of melamine urea formaldehyde resin caused to improve the mechanical strength and dimensional stability in the samples.

  19. Magnetization anomalies of fine particles interpreted as surface effects by inelastic neutron scattering

    International Nuclear Information System (INIS)

    Hennion, M.; Mirebeau, I.; Bellouard, C.

    1994-01-01

    Inelastic neutron scattering experiments on small Fe particles (R=12 Angstrom) reveal that some part of the magnetic intensity is paramagnetic at 300 K. As T decreases it freezes and develops short range ferromagnetic correlations. It is attributed to spins at the particle surface. (authors). 3 figs., 5 refs

  20. Detecting charging state of ultra-fine particles: instrumental development and ambient measurements

    Directory of Open Access Journals (Sweden)

    L. Laakso

    2007-01-01

    Full Text Available The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup – Ion-DMPS – which can be used to detect contribution of ion-induced nucleation on atmospheric new particle formation events. The device measures positively and negatively charged particles with and without a bipolar charger. The ratio between "charger off" to "charger on" describes the charging state of aerosol particle population with respect to equilibrium. Values above one represent more charges than in an equilibrium (overcharged state, and values below unity stand for undercharged situation, when there is less charges in the particles than in the equilibrium. We performed several laboratory experiments to test the operation of the instrument. After the laboratory tests, we used the device to observe particle size distributions during atmospheric new particle formation in a boreal forest. We found that some of the events were clearly dominated by neutral nucleation but in some cases also ion-induced nucleation contributed to the new particle formation. We also found that negative and positive ions (charged particles behaved in a different manner, days with negative overcharging were more frequent than days with positive overcharging.

  1. Physical properties and structure of fine core-shell particles used as packing materials for chromatography Relationships between particle characteristics and column performance.

    Science.gov (United States)

    Gritti, Fabrice; Leonardis, Irene; Abia, Jude; Guiochon, Georges

    2010-06-11

    The recent development of new brands of packing materials made of fine porous-shell particles, e.g., Halo and Kinetex, has brought great improvements in potential column efficiency, demanding considerable progress in the design of chromatographic instruments. Columns packed with Halo and Kinetex particles provide minimum values of their reduced plate heights of nearly 1.5 and 1.2, respectively. These packing materials have physical properties that set them apart from conventional porous particles. The kinetic performance of 4.6mm I.D. columns packed with these two new materials is analyzed based on the results of a series of nine independent and complementary experiments: low-temperature nitrogen adsorption (LTNA), scanning electron microscopy (SEM), inverse size-exclusion chromatography (ISEC), Coulter counter particle size distributions, pycnometry, height equivalent to a theoretical plate (HETP), peak parking method (PP), total pore blocking method (TPB), and local electrochemical detection across the column exit section (LED). The results of this work establish links between the physical properties of these superficially porous particles and the excellent kinetic performance of columns packed with them. It clarifies the fundamental origin of the difference in the chromatographic performances of the Halo and the Kinetex columns. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Physical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1-3

    Science.gov (United States)

    Kinsey, John S.; Dong, Yuanji; Williams, D. Craig; Logan, Russell

    2010-06-01

    The fine 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 for PM mass and number concentration, particle size distribution, and total volatile matter using both time-integrated and continuous sampling techniques. The experimental results showed a PM mass emission index (EI) ranging from 10 to 550 mg kg -1 fuel depending on engine type and test parameters as well as a characteristic U-shaped curve of the mass EI with increasing fuel flow for the turbofan engines tested. Also, the Teflon filter sampling indicated that ˜40-80% of the total PM mass on a test-average basis was comprised of volatile matter (sulfur and organics) for most engines sampled. The number EIs, on the other hand, varied from ˜10 15 to 10 17 particles kg -1 fuel with the turbofan engines exhibiting a logarithmic decay with increasing fuel flow. Finally, the particle size distributions of the emissions exhibited a single primary mode that were lognormally distributed with a minor accumulation mode also observed at higher powers for all engines tested. The geometric (number) mean particle diameter ranged from 9.4 to 37 nm and the geometric standard deviation ranged from 1.3 to 2.3 depending on engine type, fuel flow, and test conditions.

  3. Fine metal dust particles on the wall probes from JET-ILW

    Science.gov (United States)

    Fortuna-Zaleśna, E.; Grzonka, J.; Moon, Sunwoo; Rubel, M.; Petersson, P.; Widdowson, A.; Contributors, JET

    2017-12-01

    Collection and ex situ studies of dust generated in controlled fusion devices during plasma operation are regularly carried out after experimental campaigns. Herewith results of the dust survey performed in JET after the second phase of operation with the metal ITER-like wall (2013-2014) are presented. For the first-time-ever particles deposited on silicon plates acting as dust collectors installed in the inner and outer divertor have been examined. The emphasis is on analysing metal particles (Be and W) with the aim to determine their composition, size and surface topography. The most important is the identification of beryllium dust in the form of droplets (both splashes and spherical particles), flakes of co-deposits and small fragments of Be tiles. Tungsten and nickel rich (from Inconel) particles are also identified. Nitrogen from plasma edge cooling has been detected in all types of particles. They are categorized and the origin of various constituents is discussed.

  4. Exposure to carbon monoxide, fine particle mass, and ultrafine particle number in Jakarta, Indonesia: effect of commute mode.

    Science.gov (United States)

    Both, Adam F; Westerdahl, Dane; Fruin, Scott; Haryanto, Budi; Marshall, Julian D

    2013-01-15

    We measured real-time exposure to PM(2.5), ultrafine PM (particle number) and carbon monoxide (CO) for commuting workers school children, and traffic police, in Jakarta, Indonesia. In total, we measured exposures for 36 individuals covering 93 days. Commuters in private cars experienced mean (st dev) exposures of 22 (9.4) ppm CO, 91 (38) μg/m(3)PM(2.5), and 290 (150)×10(3) particles cm(-3). Mean concentrations were higher in public transport than in private cars for PM(2.5) (difference in means: 22%) and particle counts (54%), but not CO, likely reflecting in-vehicle particle losses in private cars owing to air-conditioning. However, average commute times were longer for private car commuters than public transport commuters (in our sample, 24% longer: 3.0 vs. 2.3 h per day). Commute and traffic-related exposures experienced by Jakarta residents are among the highest in the world, owing to high on-road concentrations and multi-hour commutes. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Single-particle effects in fine structure of super-asymmetric fission

    International Nuclear Information System (INIS)

    Mirea, M.

    1999-01-01

    Energy spectrum measurements concerning the 14 C decay from 223 Ra revealed a fine structure with an intense branch on the excited state of the daughter 209 Pb. Apart the great number of microscopic--macroscopic attempts of different authors in describing this behavior (compiled recently), this phenomenon was explained quantitatively using the Landau--Zener effect, i.e., the promotion mechanism of a unpaired nucleon between two levels characterised by the same quantum numbers connected to some symmetries of the nuclear system in the region where an avoided level crossing is exhibited. The adiabatic levels during the super-asymmetric fission process were determined with a new version of the two--centre shell model especially constructed for very large mass--asymmetries. The half--lives are obtained in the framework of the Wentzel--Kramers--Brillouin approximation. The amount of the variation of the barrier height in the excited channels was estimated accounting the specialization energy which can be interpreted as the excess of the energy of a nucleon with a given spin over the energy for the same spin nucleon state of lowest energy. It is evidenced that the fine structure of cluster decay is due to two competitive effects: the Landau--Zener effect which enhances the probability to have an excited daughter in the final channel and the specialization energy which increases the potential barrier and therefore leads to a diminution of the penetrability. This formalism was used for predictions of the fine structure in the case of 14 C decay of 225 Ac and to explain the fine structure of alpha decay. (author)

  6. The Effect of Silver Nano Particles on Candida Albicans and Streptococcus Mutans in Denture Acrylic Resins

    Directory of Open Access Journals (Sweden)

    Ahmad Ghahremanloo

    2016-03-01

    Full Text Available Introduction: Denture stomatitis is a common complication in patients wearing dentures and preventing the proliferation of related microorganisms and their induced infections is noteworthy. The aim of the present study was to assess the antimicrobial effect of acrylic resins containing various concentrations of silver nanoparticles, on Candida albicans and Streptococcus mutans. Materials and Methods: In this in vitro study, the effect of four different concentrations of silver nanoparticles in 160 acrylic samples (10mm *4mm on standard and hospital isolated strains of two different microorganisms were investigated. The samples were soaked (containing silver nanoparticles and control in bacterial suspension and the antimicrobial tests were performed after 0, 1, 6 and 24 hours. Mean and standard deviation were used to describe the data and one-way variance analysis test was performed to compare groups. Results: Results have shown that in concentration of 2.5% the highest mean difference for standard S. mutans, after 24h of exposure was 540.0±14.4 (P

  7. The effect of electrons surface scattering on fine metal particle electromagnetic radiation absorption

    Directory of Open Access Journals (Sweden)

    I.A. Kuznetsova

    2014-03-01

    Full Text Available The magnetic dipole absorption cross section of spherical shaped metal particle was calculated in terms of kinetic approach. The particle considered was placed in the field of plane electromagnetic wave. The model of boundary conditions taking into account the dependence of the reflectivity coefficient both on the surface roughness parameter and on the electrons incidence angle was investigated. The results obtained were compared with theoretical computation results for model of combined diffusion-specular boundary conditions of Fuchs.

  8. Importance of fine particles in pesticide runoff from concrete surfaces and its prediction.

    Science.gov (United States)

    Jiang, Weiying; Gan, Jay

    2012-06-05

    Pesticides such as pyrethroids have been frequently found in runoff water from urban areas and the offsite movement is a significant cause for aquatic toxicities in urban streams and estuaries. To better understand the origination of pesticide residues in urban runoff, we investigated the association of pyrethroid residues with loose particles in runoff water from concrete surfaces after treatment with commercial products of bifenthrin and permethrin. In runoff water generated from simulated precipitations after 1 to 89 d exposure under dry outdoor conditions, over 80% of the pesticides was found on particles >0.7 μm for most treatments. The solid-water partitioning coefficient (K(d)) on day 1 was estimated to be 2.4 × 10(3) to 1.1 × 10(5) L/kg for permethrin and bifenthrin on these solids. Except for solid formulations, the pesticide-laden particles likely originated from dust particles preexisting on the concrete before treatment and the disintegration of the surficial concrete matter through weathering. We consequently tested a simple sponge-wipe method to collect and analyze the loose particles on concrete. Concurrent analyses (n = 30) showed an excellent linear correlation between the amount of pesticides transferrable to runoff water and that on the wipe (R(2) = 0.78, slope = 1.13 ± 0.11, P contaminating runoff water before runoff actually occurs. The importance of loose particles should be considered when developing practices to mitigate pesticide runoff contamination from urban residential areas.

  9. 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.

  10. 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

  11. A two-stage treatment for Municipal Solid Waste Incineration (MSWI) bottom ash to remove agglomerated fine particles and leachable contaminants.

    Science.gov (United States)

    Alam, Qadeer; Florea, M V A; Schollbach, K; Brouwers, H J H

    2017-09-01

    In this lab study, a two-stage treatment was investigated to achieve the valorization of a municipal solid waste incineration (MSWI) bottom ash fraction below 4mm. This fraction of MSWI bottom ash (BA) is the most contaminated one, containing potentially toxic elements (Cu, Cr, Mo and Sb), chlorides and sulfates. The BA was treated for recycling by separating agglomerated fine particles (≤125µm) and soluble contaminants by using a sequence of sieving and washing. Initially, dry sieving was performed to obtain BA-S (≤125µm), BA-M (0.125-1mm) and BA-L (1-4mm) fractions from the original sample. The complete separation of fine particles cannot be achieved by conventional sieving, because they are bound in a cementitious matrix around larger BA grains. Subsequently, a washing treatment was performed to enhance the liberation of the agglomerated fine particles from the BA-M and BA-L fractions. These fine particles were found to be similar to the particles of BA-S fraction in term of chemical composition. Furthermore, the leaching behavior of Cr, Mo Sb, chlorides and sulfates was investigated using various washing parameters. The proposed treatment for the separation of agglomerated fine particles with dry sieving and washing (L/S 3, 60min) was successful in bringing the leaching of contaminants under the legal limit established by the Dutch environmental norms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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.

  13. [Pollution characteristics and source of the atmospheric fine particles and secondary inorganic compounds at Mount Dinghu in autumn season].

    Science.gov (United States)

    Liu, Zi-Rui; Wang, Yue-Si; Liu, Quan; Liu, Lu-Ning; Zhang, De-Qiang

    2011-11-01

    Real-time measurements of PM2.5, secondary inorganic compounds in PM2.5 (SO4(2-), NH4(+), and NO3(-)) and related gaseous pollutants were conducted at Mount Dinghu, a regional background station of the Pearl River Delta (PRD), in October and November 2008 by using a conventional R&P TEOM and a system of rapid collection of fine particles and ion chromatography (RCFP-IC). Sources and transportation of atmospheric particles during the experiment were discussed with principal component analysis and backward trajectories calculated using HYSPLIT model. The average daily mass concentrations of PM2.5 were 76.9 microg x m(-3) during sampling period, and average daily mass concentrations of SO4(2-), NH4(+), and NO3(-) were 20.0 microg x m(-3), 6.8 microg x m(-3) and 2.6 microg x m(-3), respectively. The sum of these three secondary inorganic compounds accounted for more than one third of the PM2.5 mass concentration, which had become the major source of atmospheric fine particles at Mount Dinghu. The diurnal variation of PM2.5, SO4(2-), and NH4(+) all showed a "bimodal" distribution with two peaks appeared at 10:00 am and at 16:00 pm, respectively, whereas NO3(-s) howed "single peak" distribution peaked at 10:00 am. The mass concentrations of SO4(2-) in PM2.5 had the similar diurnal variation with that of SO2, SO4(2-) in PM2.5 was mainly transformed from SO2, whereas NO3(-) showed difference diurnal variation with that of NO2, and the second conversion rate of NO2 was far lower than that of SO2. NH4(+) in PM2.5 existed mainly in the form of sulfate, nitrate and chloride. Both of principal component analysis and back trajectory analysis showed that the variations of PM2.5 and secondary inorganic compounds at Mount Dinghu were mainly affected by the long-range transport air mass passed over Guangzhou, Huizhou and other highly industrialized areas which carried air pollutants to the observation site, at the same time local sulfate originated from secondary formation also

  14. 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.

  15. Fine-Grid Eulerian Simulation of Sedimenting Particles: Liquid-Solid and Gas-Solid Systems

    Science.gov (United States)

    Zaheer, Muhammad; Hamid, Adnan; Ullah, Atta

    2017-06-01

    A computational study of mono-dispersed spherical sedimenting particles was performed with Eulerian two-fluid model (TFM). The aim was to investigate the applicability and accuracy of TFM with proper closure laws from kinetic theory of granular flow (KTGF) for sedimentation studies. A three-dimensional cubical box with full periodic boundaries was employed. The volume fraction of particles (ϕs) was varied from very low (ϕs = 0.01) to dense regimes (ϕs = 0.4), for two different types of fluids, i.e., gas and liquid. It is observed that the results for liquid-solid sedimentation are in good agreement with simulation studies and experimental correlation of Richardson and Zaki. However, for gas-solid system, results show different behavior at low volume fractions, which is more pronounced with increasing Stokes number. This can be attributed to inhomogeneous distribution of solid particles in gas phase at dilute concentrations, which causes meso-scale clusters and streamers formation. It is concluded that the ratio of density of particles to density of fluid which appears in Stokes number plays critical role in settling behavior of particles.

  16. Emission, immission and measurement of fine and ultrafine particles; Emission, Immission und Messung feiner und ultrafeiner Partikel

    Energy Technology Data Exchange (ETDEWEB)

    Cyrys, Josef [Univ. Muenchen (Germany). Inst. fuer Medizinische Informationsverarbeitung, Biometrie und Epidemiologie; Heinrich, Joachim; Peters, Anette [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany). Institut fuer Epidemiologie; Kreyling, Wolfgang [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany). Institut fuer Inhalationsbiologie; Wichmann, H.-Erich [Univ. Muenchen (Germany). Inst. fuer Medizinische Informationsverarbeitung, Biometrie und Epidemiologie; GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany). Institut fuer Epidemiologie

    2002-07-01

    Recent toxicological and epidemiological studies suggest that fine and ultrafine particles are associated with human health effects. Based on the capacity to penetrate the respiratory tract two fractions of particles are widely considered: PM{sub 10} (particles < 10 {mu}m) and PM{sub 2.5} (particles < 2,5 {mu}m). Ultrafine particles consist of particles smaller than 0.1 {mu}m in diameter. In this overview we discuss the formation of particles and the most important properties of particles. In addition, we summarize the current knowledge of measurement methods, emission and immission of PM{sub 10}, PM{sub 2.5} and ultrafine particles. A variety of methods are now available for sampling of particles depending on the particle fraction. The recent development of the measurement technology allows the measurement of the size-stratified particle number and mass. Since the early nineties such measurements are conducted in Erfurt/Germany. The average PM{sub 2.5} mass concentration decreased from 82 {mu}g/m{sup 3} in winter 1991/92 to 28 {mu}g/m{sup 3} in winter 1997/98. In contrast, in the same time period the number concentration of ultrafine particles increased from 13 000 to around 19 000 particles/cm{sup 3}. Finally, we discuss the personal exposure to particles and its relation to ambient and indoor particle concentrations. (orig.) [German] Neuere toxikologische und epidemiologische Untersuchungen zeigen, dass vor allem die feinen und sehr feinen Partikel des Schwebstaubes von besonderer gesundheitlicher Relevanz sind. Resultierend aus den Untersuchungen der Lungengaengigkeit von Partikeln werden heutzutage vor allem zwei Fraktionen, PM{sub 10} (Partikel < 10 {mu}m) und PM{sub 2.5} (Partikel < 2,5 {mu}m), hervorgehoben. Partikel mit einem Durchmesser < 0,1 {mu}m werden als ultrafeine Partikel (UP) bezeichnet. In dieser Uebersicht werden die Bildungsmechanismen sowie die wichtigsten Eigenschaften der Partikel beschrieben. Darueber hinaus wird der aktuelle Wissenstand zu

  17. Aerosol-phase Activity of Iodine Captured from a Triiodide Resin Filter on Fine Particles Containing an Infectious Virus

    Science.gov (United States)

    2015-01-01

    system with a GP 40 gradient pump; the ED 50 electrochemical detector used a silver working electrode (Dionex Corporation, Sunnyvale, CA) (Meli chercik et...ion specific electrode and high performance liquid chromatography methods for the determination of iodide in milk. J Dairy Sci 89, 934 937. Messier...Effect of antimicrobial air filter treatment on bacterial survival. Fibres Textiles East Eur 19, 73 77. Muus, J., Coons, A.H. and Salter, W.T. (1941

  18. Assessing the in vitro toxicity of the lunar dust environment using respiratory cells exposed to Al(2)O(3) or SiO(2) fine dust particles.

    Science.gov (United States)

    Jordan, Jacqueline A; Verhoff, Ashley M; Morgan, Julie E; Fischer, David G

    2009-12-01

    Prior chemical and physical analysis of lunar soil suggests a composition of dust particles that may contribute to the development of acute and chronic respiratory disorders. In this study, fine Al(2)O(3) (0.7 μm) and fine SiO(2) (mean 1.6 μm) were used to assess the cellular uptake and cellular toxicity of lunar dust particle analogs. Respiratory cells, murine alveolar macrophages (RAW 264.7) and human type II epithelial (A549), were cultured as the in vitro model system. The phagocytic activity of both cell types using ultrafine (0.1 μm) and fine (0.5 μm) fluorescent polystyrene beads was determined. Following a 6-h exposure, RAW 264.7 cells had extended pseudopods with beads localized in the cytoplasmic region of cells. After 24 h, the macrophage cells were rounded and clumped and lacked pseudopods, which suggest impairment of phagocytosis. A549 cells did not contain beads, and after 24 h, the majority of the beads appeared to primarily coat the surface of the cells. Next, we investigated the cellular response to fine SiO(2) and Al(2)O(3) (up to 5 mg/ml). RAW 264.7 cells exposed to 1.0 mg/ml of fine SiO(2) for 6 h demonstrated pseudopods, cellular damage, apoptosis, and necrosis. A549 cells showed slight toxicity when exposed to fine SiO(2) for the same time and dose. A549 cells had particles clustered on the surface of the cells. Only a higher dose (5.0 mg/ml) of fine SiO(2) resulted in a significant cytotoxicity to A549 cells. Most importantly, both cell types showed minimal cytotoxicity following exposure to fine Al(2)O(3). Overall, this study suggests differential cellular toxicity associated with exposure to fine mineral dust particles.

  19. Replacement of fine particle purification filter of the PHT purification system - 15083

    International Nuclear Information System (INIS)

    Lee, D.S.

    2015-01-01

    The increase of chalk river unidentified deposit (CRUD), a particulate corrosion product in PHT (primary heat transport) system with increased operating years of a nuclear power plant causes: -) the problems of increased heavy water decomposition and deuterium formation reaction due to catalytic reaction with CRUD, -) damage to PHT pump seal due to a corrosion product, -) damage to fuel channel closure seal, and increased radiation exposure of workers due to elevated dose rate in steam generator water chamber. Wolsung unit 3 and 4 have replaced fine filter media in PHT purification system in phases reducing the pore size of the filter media (5 μm → 2 μm → 1 μm → 0.45 μm) to solve this problem. The phased replacement of fine filter media by the one with a smaller pore size reduced CRUD in PHT system significantly and also radiation dose rate in steam generator water chamber. Accordingly, many problems related to the aging of a plant (including increased radiation exposure of workers during outage, damage to mechanical seal of PHT pump) have been solved. (author)

  20. Experimental investigation of acoustic agglomeration systems for fine particle control. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, D.T.; Lee, P.; Wegrzyn, J.; Chou, K.H.; Cheng, M.T.; Patel, S.

    1979-10-01

    The feasibility of using an acoustic agglomerator (AA) as a preconditioner in the upstream of conventional devices such as an electrostatic precipitator, a scrubber, a filter, or a cyclone are investigated. The objective is to agglomerate all finer particles into coarser ones in an acoustic agglomerator and then remove them more effectively by one of the conventional devices. Laboratory-scale experiments were performed using NH/sub 4/Cl and fly ash redispersed aerosols. Turbulence caused by intensive sound fields under standing-wave condition has been found to be extremely effective for aerosol agglomeration. The nature and the energy dissipation rate of the acoustic turbulence are determined by using hot-film (or hot-wire) anemometry and Fast Fourier Transform (FFT) data processing equipment. The root-mean-square turbulent velocity, which is directly proportional to acoustic agglomeration rate, is experimentally found to have a I/sup 1/2/(I: acoustic intensity) dependence, but is relatively independent of the acoustic frequency. The results obtained from this program show that acoustic agglomeration is effective as a particle pre-conditioner which can increase approximately one order of magnitude in mean particle diameter (2..mu..m ..-->.. 20..mu..m). As a flow-through standing wave device, it can be used to facilitate the removal of dust particles in a subsequent inertia base separation device.

  1. 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 us...

  2. Ultrafine and Fine Particles and Hospital Admissions in Central Europe Results from the UFIREG Study

    Czech Academy of Sciences Publication Activity Database

    Lanzinger, S.; Schneider, A.; Breitner, S.; Stafoggia, M.; Erzen, I.; Dostál, Miroslav; Pastorková, Anna; Bastian, S.; Cyrys, J.; Zscheppang, A.; Kolodnitská, T.; Peters, A.

    2016-01-01

    Roč. 194, č. 10 (2016), s. 1233-1241 ISSN 1073-449X Institutional support: RVO:68378041 Keywords : ultrafine particles * particulate matter * hospital admissions * respiratory Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 13.204, year: 2016

  3. 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...

  4. Wastewater diffusive dilution and sedimentation of the fine contaminated particles for nonuniform flow in open channels

    Directory of Open Access Journals (Sweden)

    Lyapin Anton

    2018-01-01

    Full Text Available The influence of non-uniformity on mass transfer processes in open channels have been investigated under the action of urbanization factors. The study is related to the urgent problem of environmental degradation of water objects in urbanized areas. It is known that the water quality in the water objects depends on the manner in which the contaminants spread how they mix with the river water and diluted by it. The main results of the study consist of recommendations to incorporate non-uniformity factor to the calculation of diffusion dilution of wastewater and prediction of river processes. So the effect of the flow non-uniformity on the diffusion model of pollutants dilution and diffusion coefficient have been investigated. Formulas for the concentration profiles calculating and the average concentration of fine particulate matter in nonuniform gradually varied flow were presented. The deposition length of suspended contaminants were received, based on the hydraulic resistance laws of nonuniform gradually varied flow.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  6. Simultaneous removal of mercury, PCDD/F, and fine particles from flue gas.

    Science.gov (United States)

    Korell, Jens; Paur, Hanns-R; Seifert, Helmut; Andersson, Sven

    2009-11-01

    A multifunctional scrubber (MFS) has been developed to reduce the complexity of flue gas cleaning plants. The MFS integrates an oxidizing scrubber equipped with a dioxin-absorbing tower packing material and a space charge electrostatic precipitator. All these processes have been previously developed at Forschungszentrum Karlsruhe. In the described multifunctional scrubber, mercury, sulfur dioxide, hydrogen chloride, polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and submicrometer particles are removed simultaneously. A MFS pilot plant with a flue gas volume flow of 250 m(3)/h has been installed in a slipstream of a waste incineration pilot plant. Pilot scale testing was performed to measure mercury, particles, and PCDD/F in the raw and clean gas. After optimization of the process these three flue gas components were separated from the flue gas in the range 87-97%.

  7. Respiratory health effects of ultrafine and fine particle exposure in cyclists.

    Science.gov (United States)

    Strak, Maciej; Boogaard, Hanna; Meliefste, Kees; Oldenwening, Marieke; Zuurbier, Moniek; Brunekreef, Bert; Hoek, Gerard

    2010-02-01

    Monitoring studies have shown that commuters are exposed to high air pollution concentrations, but there is limited evidence of associated health effects. We carried out a study to investigate the acute respiratory health effects of air pollution related to commuting by bicycle. Twelve healthy adults cycled a low- and a high-traffic intensity route during morning rush hour in Utrecht, The Netherlands. Exposure to traffic-related air pollution was characterised by measurements of PM(10), soot and particle number. Before, directly after and 6 h after cycling we measured lung function (FEV(1), FVC, PEF), exhaled NO (FE(NO)) and respiratory symptoms. The association between post- minus pre-exposure difference in health effects and exposure during cycling was evaluated with linear regression models. The average particle number concentration was 59% higher, while the average soot concentration was 39% higher on the high-traffic route than on the low-traffic route. There was no difference for PM(10). Contrary to our hypothesis, associations between air pollution during cycling and lung function changes immediately after cycling were mostly positive. Six hours after cycling, associations between air pollution exposure and health were mostly negative for lung function changes and positive for changes in exhaled NO, although non-significant. We found substantial differences in ultrafine particle number and soot exposure between two urban cycling routes. Exposure to ultrafine particles and soot during cycling was weakly associated with increased exhaled NO, indicative of airway inflammation, and decrements in lung function 6 h after exposure. A limitation of the study was the relatively small sample size.

  8. Estimation of Fine and Oversize Particle Ratio in a Heterogeneous Compound with Acoustic Emissions

    Directory of Open Access Journals (Sweden)

    Ejay Nsugbe

    2018-03-01

    Full Text Available The final phase of powder production typically involves a mixing process where all of the particles are combined and agglomerated with a binder to form a single compound. The traditional means of inspecting the physical properties of the final product involves an inspection of the particle sizes using an offline sieving and weighing process. The main downside of this technique, in addition to being an offline-only measurement procedure, is its inability to characterise large agglomerates of powders due to sieve blockage. This work assesses the feasibility of a real-time monitoring approach using a benchtop test rig and a prototype acoustic-based measurement approach to provide information that can be correlated to product quality and provide the opportunity for future process optimisation. Acoustic emission (AE was chosen as the sensing method due to its low cost, simple setup process, and ease of implementation. The performance of the proposed method was assessed in a series of experiments where the offline quality check results were compared to the AE-based real-time estimations using data acquired from a benchtop powder free flow rig. A designed time domain based signal processing method was used to extract particle size information from the acquired AE signal and the results show that this technique is capable of estimating the required ratio in the washing powder compound with an average absolute error of 6%.

  9. Study of fine particles (PM2.5) during the dry-hot time in the Toluca city

    International Nuclear Information System (INIS)

    Rosendo G, V.; Aldape U, F.

    2007-01-01

    The first obtained results of the analysis of the fine fraction particulate material (PM 2.5 ) samples collected in the Toluca City are presented. The samples analyzed are part of a more extensive campaign that contemplates the low project the one which one carries out this work and that it integrates three climatic times (dry-hot, of rains and dry-cold time) with the purpose of investigating the events of contamination in one complete year. The obtained results correspond to the dry-hot time and its include mainly the database starting from which the temporal variation graphs were obtained, the correlations among elements and the enrichment factor, as well as a multiple correlation analysis. Additionally the gravimetry was measured. Its are not observed significant episodes, however, it was found an element of the traces order, little common in other atmospheric studies as it is arsenic. From the gravimetry it was deduced that the air quality standard of fine particle, it does not violate. (Author)

  10. Influence of petrographic textures on the shapes of impact experiment fine fragments measuring several tens of microns: Comparison with Itokawa regolith particles

    Science.gov (United States)

    Michikami, Tatsuhiro; Kadokawa, Tokiyuki; Tsuchiyama, Akira; Hagermann, Axel; Nakano, Tsukasa; Uesugi, Kentaro; Hasegawa, Sunao

    2018-03-01

    In 2010, fine regolith particles on asteroid Itokawa were recovered by the Hayabusa mission. The three-dimensional microstructure of 48 Itokawa particles smaller than 120 μm was examined in previous studies. The shape distribution of Itokawa particles is distributed around the mean values of the axial ratio 2:√2:1, which is similar to laboratory impact fragments larger than several mm created in catastrophic disruptions. Thus, the Itokawa particles are considered to be impact fragments on the asteroid's surface. However, there have never been any laboratory impact experiments investigating the shapes of fine fragments smaller than 120 μm, and little is known about the relation between the shapes of fine fragments and the petrographic textures within those fragments. In this study, in order to investigate the relation between the petrographic textures and the shapes of fine fragments by impacts, the shapes of 2163 fine fragments smaller than 120 μm are examined by synchrotron radiation-based microtomography at SPring-8. Most samples are fine fragments from basalt targets, obtained in previous laboratory impact experiments by Michikami et al. (2016). Moreover, two impacts into L5 chondrite targets were carried out and the shapes of their fine fragments are examined for comparison. The results show that the shape distributions of fine fragments in basalt targets are similar regardless of impact energy per target mass (in contract to the shape distribution of relatively large fragments, which are affected by impact energy), and are similar to those in L5 chondrite targets and Itokawa regolith particles. The physical process producing these fine fragments would be due to multiple rarefaction waves in the target. Besides, the petrographic textures do not significantly affect the shapes of fine fragments in our experiments. On the other hand, according to Molaro et al. (2015), the shapes of the fragments produced by thermal fatigue by the day-night temperature cycles

  11. 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.

  12. Rock Magnetic Characterization of fine Particles from car Engines, Break pads and Tobacco: An Environmental Pilot Study

    Science.gov (United States)

    Herrero-Bervera, E.; Lopez, V. A.; Gerstnecker, K.; Swilley, B.

    2017-12-01

    Today, it is very well known that small magnetic particles are very harmful to the health of humans. For the first time we have conducted an environmental pilot study of fine magnetic particles on the island of Oahu, Hawaii, of particulate matter (pm) 60, pm=10, and pm= 2.5. In order to do a rock magnetic characterization we have preformed low field susceptibility versus temperature (k-T) experiments to determine the Curie points of small particles collected from exhaust pipes, as well as from brake pads of 4 different types of car engines using octane ratings of 85, 87 and 92. The Curie point determinations are very well defined and range from 292 °C through 393 °C to 660 °C. In addition, we have conducted magnetic granulometry experiments on raw tobacco, burnt ashes as well as on car engines and brake pads in question. The results of the experiments show ferro- and ferrimagnetic hysteresis loops with magnetic grain sizes ranging from superparamagnetic-multidomain (SP_MD), multi-domain (MD) and pseudo-single domain (PSD) shown on the modified Day et al. diagram of Dunlop (2002). Thus far, the results we have obtained from this pilot study are in agreement with other studies conducted from cigarette ashes from Bulgaria (Jordanova et al., 2005). Our results could be correlated to the traffic-related PM in Rome, Italy where the SP fraction mainly occurs as coating of MD particles that originated by localized stress in the oxidized outer shell surrounding the unoxidized core of magnetite like grains as published by Sagnotti and Winkler (2012).

  13. 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.

  14. Fine particles from Independence Day fireworks events: chemical characterization and source apportionment

    Science.gov (United States)

    Zhang, J.; Lance, S.; Freedman, J. M.; Yele, S.; Crandall, B.; Wei, X.; Schwab, J. J.

    2017-12-01

    To study the impact of fireworks (FW) events on air quality, aerosol particles from FW displays were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and collocated instruments during the Independence Day holiday 2017 in Albany, NY. Three FW events were identified through potassium ion (K+) signals in the mass spectra. The largest FW event signal measured at two different locations was the Independence Day celebration in Albany, with maximum aerosol concentrations of about 55 ug/m3 at the downtown site and 35 ug/m3 at the uptown site. The aerosol concentration peaked at the uptown site about 2 hours later than at the downtown site. FW events resulted in significant increases in both organic and inorganic (K+, sulfate, chloride) compounds. Among the organics, Positive Matrix Factorization (PMF) identified one special FW organic aerosol factor (FW-OA), which was highly oxidized. The intense emission of FW particles from the Independence Day celebration contributed 76% of total PM1 at the uptown site. The aerosol and wind LiDAR measurements showed two distinct pollution sources, one from the Independence Day FW event in Albany, and another aerosol source transported from other areas, potentially associated with other town's FW events.

  15. Fine particle pH and gas-particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign

    Science.gov (United States)

    Guo, Hongyu; Liu, Jiumeng; Froyd, Karl D.; Roberts, James M.; Veres, Patrick R.; Hayes, Patrick L.; Jimenez, Jose L.; Nenes, Athanasios; Weber, Rodney J.

    2017-05-01

    pH is a fundamental aerosol property that affects ambient particle concentration and composition, linking pH to all aerosol environmental impacts. Here, PM1 and PM2. 5 pH are calculated based on data from measurements during the California Research at the Nexus of Air Quality and Climate Change (CalNex) study from 15 May to 15 June 2010 in Pasadena, CA. Particle pH and water were predicted with the ISORROPIA-II thermodynamic model and validated by comparing predicted to measured gas-particle partitioning of inorganic nitrate, ammonium, and chloride. The study mean ± standard deviation PM1 pH was 1.9 ± 0.5 for the SO42--NO3--NH4+-HNO3-NH3 system. For PM2. 5, internal mixing of sea salt components (SO42--NO3--NH4+-Na+-Cl--K+-HNO3-NH3-HCl system) raised the bulk pH to 2.7 ± 0.3 and improved predicted nitric acid partitioning with PM2. 5 components. The results show little effect of sea salt on PM1 pH, but significant effects on PM2. 5 pH. A mean PM1 pH of 1.9 at Pasadena was approximately one unit higher than what we have reported in the southeastern US, despite similar temperature, relative humidity, and sulfate ranges, and is due to higher total nitrate concentrations (nitric acid plus nitrate) relative to sulfate, a situation where particle water is affected by semi-volatile nitrate concentrations. Under these conditions nitric acid partitioning can further promote nitrate formation by increasing aerosol water, which raises pH by dilution, further increasing nitric acid partitioning and resulting in a significant increase in fine particle nitrate and pH. This study provides insights into the complex interactions between particle pH and nitrate in a summertime coastal environment and a contrast to recently reported pH in the eastern US in summer and winter and the eastern Mediterranean. All studies have consistently found highly acidic PM1 with pH generally below 3.

  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. Respiratory disease and particulate air pollution in Santiago Chile: contribution of erosion particles from fine sediments.

    Science.gov (United States)

    Garcia-Chevesich, Pablo A; Alvarado, Sergio; Neary, Daniel G; Valdes, Rodrigo; Valdes, Juan; Aguirre, Juan José; Mena, Marcelo; Pizarro, Roberto; Jofré, Paola; Vera, Mauricio; Olivares, Claudio

    2014-04-01

    Air pollution in Santiago is a serious problem every winter, causing thousands of cases of breathing problems within the population. With more than 6 million people and almost two million vehicles, this large city receives rainfall only during winters. Depending on the frequency of storms, statistics show that every time it rains, air quality improves for a couple of days, followed by extreme levels of air pollution. Current regulations focus mostly on PM10 and PM2.5, due to its strong influence on respiratory diseases. Though more than 50% of the ambient PM10s in Santiago is represented by soil particles, most of the efforts have been focused on the remaining 50%, i.e. particulate material originating from fossil and wood fuel combustion, among others. This document emphasizes the need for the creation of erosion/sediment control regulations in Chile, to decrease respiratory diseases on Chilean polluted cities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. African Anthropogenic Combustion Emissions: Estimate of Regional Mortality Attributable to Fine Particle Concentrations in 2030

    Science.gov (United States)

    Liousse, C.; Roblou, L.; Assamoi, E.; Criqui, P.; Galy-Lacaux, C.; Rosset, R.

    2014-12-01

    Fossil fuel (traffic, industries) and biofuel (domestic fires) emissions of gases and particles in Africa are expected to significantly increase in the near future, particularly due to rapid growth of African cities and megacities. In this study, we will present the most recent developments of African combustion emission inventories, including African specificities. Indeed, a regional fossil fuel and biofuel inventory for gases and particulates described in Liousse et al. (2014) has been developed for Africa at a resolution of 0.25° x 0.25° for the years 2005 and 2030. For 2005, the original database of Junker and Liousse (2008) was used after modification for updated regional fuel consumption and emission factors. Two prospective inventories for 2030 are derived based on Prospective Outlook on Long-term Energy Systems (POLES) model (Criqui, 2001). The first is a reference scenario (2030ref) with no emission controls and the second is for a "clean" scenario (2030ccc*) including Kyoto policy and African specific emission control. This inventory predicts very large increases of pollutant emissions in 2030 (e.g. contributing to 50% of global anthropogenic organic particles), if no emission regulations are implemented. These inventories have been introduced in RegCM4 model. In this paper we will focus on aerosol modelled concentrations in 2005, 2030ref and 2030ccc*. Spatial distribution of aerosol concentrations will be presented with a zoom at a few urban and rural sites. Finally mortality rates (respiratory, cardiovascular) caused by anthropogenic PM2.5 increase from 2005 to 2030, calculated following Lelieveld et al. (2013), will be shown for each scenarios. To conclude, this paper will discuss the effectiveness of scenarios to reduce emissions, aerosol concentrations and mortality rates, underlining the need for further measurements scheduled in the frame of the new DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions) program.

  19. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. 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

  1. Important sources and chemical species of ambient fine particles related to adverse health effects

    Science.gov (United States)

    Heo, J.

    2017-12-01

    Although many epidemiological studies have reported that exposure to ambient fine particulate matter (PM2.5) has been linked to increases in mortality and mobidity health outcomes, the key question of which chemical species and sources of PM2.5 are most harmful to public health remains unanswered in the air pollution research area. This study was designed to address the key question with evaluating the risks of exposure to chemical species and source-specific PM2.5 mass on morbidity. Hourly measurements of PM2.5 mass and its major chemical species, including organic carbon, elemental carbon, ions, and trace elements, were observed from January 1 to December 31, 2013 at four of the PM2.5 supersites in urban environments in Korea and the reuslts were used in a positive matrix factorization to estimate source contributions to PM2.5 mass. Nine sources, including secondary sulfate, secondary nitrate, mobile, biomass burning, roadway emission, industry, oil combustion, soil, and aged sea salt, were identified and secondary inorganic aerosol factors (i.e. secondary sulfalte, and secondary nitrate) were the dominant sources contributing to 40% of the total PM2.5 mass in the study region. In order to evaluate the risks of exposure to chemical species and sources of PM2.5 on morbidity, emergency room visits for cardivascular disease and respiratory disease were considered. Hourly health outcomes were compared with hourly measurments of the PM2.5 chemical species and sources using a poission generalized linear model incorporating natural splines, as well as time-stratified case-crossover design. The PM2.5 mass and speveral chemical components, such as organic carbon, elemetal carbon, zinc, and potassium, were strongly associated with morbidity. Source-apporitionmened PM2.5 mass derived from biomass burning, and mobile sources, was significantly associated with cardiovascular and respiratory diseases. The findings represent that local combustion may be particularly important

  2. 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.

  3. Effect of nano SiO{sub 2} particles on the morphology and mechanical properties of POSS nanocomposite dental resins

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yizhi; Sun, Yi, E-mail: sunyi@hit.edu.cn; Zeng, Fanlin [Harbin Institute of Technology, Department of Astronautic Science and Mechanics (China); Xie, Weili, E-mail: xwl811@126.com [Harbin Medical University, Department of Stomatology (China); Liu, Yang [Harbin Stomatology Hospital (China); Geng, Lin [Harbin Institute of Technology, School of Materials Science and Engineering (China)

    2014-12-15

    Nanocomposite dental resins composed of polyhedral oligomeric silsesquioxane nanocomposite matrix and 0, 0.5,1, 1.5 and 2 wt% nano SiO{sub 2} as filler were prepared by light curing method. The nanocomposite resins were characterized by performing compressive, three-point flexure, nanoindentation and nanoscratch testings as well as optical microscopy and scanning electron microscope analysis. The effects of different nano SiO{sub 2} contents were studied on compressive strength, flexural strength, hardness and resistance of composite resin. From the mechanical results, it was found that nano SiO{sub 2} effectively enhanced the mechanical properties of the composite resins at low content. With the increase of the nano SiO{sub 2} content, the mechanical properties decreased. It was attributed to the content of nano SiO{sub 2} and dispersion of nanoparticles in matrix.

  4. 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

  5. Analytical electron microscopy of fine-grained phases in primitive interplanetary dust particles and carbonaceous chondrites

    Science.gov (United States)

    Mackinnon, Ian D. R.; Rietmeijer, Frans J. M.; Mckay, David S.

    1987-01-01

    In order to describe the total mineralogical diversity within primitive extraterrestrial materials, individual interplanetary dust particles (IDPs) collected from the stratosphere as part of the JSC Cosmic Dust Curatorial Program were analyzed using a variety of AEM techniques. Identification of over 250 individual grains within one chondritic porous (CP) IDP shows that most phases could be formed by low temperature processes and that heating of the IDP during atmospheric entry is minimal and less than 600 C. In a review of the mineralogy of IDPs, it was suggested that the occurrence of other silicates such as enstatite whiskers is consistent with the formation in an early turbulent period of the solar nebula. Experimental confirmation of fundamental chemical and physical processes in a stellar environment, such as vapor phase condensation, nucleation, and growth by annealing, is an important aspect of astrophysical models for the evolution of the Solar System. A detailed comparison of chondritic IDP and carbonaceous chondrite mineralogies shows significant differences between the types of silicate minerals as well as the predominant oxides.

  6. Fine Particle Sensor Based on Multi-Angle Light Scattering and Data Fusion

    Directory of Open Access Journals (Sweden)

    Wenjia Shao

    2017-05-01

    Full Text Available Meteorological parameters such as relative humidity have a significant impact on the precision of PM2.5 measurement instruments based on light scattering. Instead of adding meteorological sensors or dehumidification devices used widely in commercial PM2.5 measurement instruments, a novel particle sensor based on multi-angle light scattering and data fusion is proposed to eliminate the effect of meteorological factors. Three photodiodes are employed to collect the scattered light flux at three distinct angles. Weather index is defined as the ratio of scattered light fluxes collected at the 40° and 55° angles, which can be used to distinguish the mass median diameter variation caused by different meteorological parameters. Simulations based on Lorenz-Mie theory and field experiments establish the feasibility of this scheme. Experimental results indicate that mass median diameter has less effect on the photodiode at the 55° angle in comparison with photodiodes at the 40° angle and 140° angle. After correction using the weather index, the photodiode at the 40° angle yielded the best results followed by photodiodes at the 55° angle and the 140° angle.

  7. Analytical electron microscopy of fine-grained phases in primitive interplanetary dust particles and carbonaceous chondrites

    International Nuclear Information System (INIS)

    Mackinnon, I.D.R.; Rietmeijer, F.J.M.; Mckay, D.S.

    1987-01-01

    In order to describe the total mineralogical diversity within primitive extraterrestrial materials, individual interplanetary dust particles (IDPs) collected from the stratosphere as part of the JSC Cosmic Dust Curatorial Program were analyzed using a variety of AEM techniques. Identification of over 250 individual grains within one chondritic porous (CP) IDP shows that most phases could be formed by low temperature processes and that heating of the IDP during atmospheric entry is minimal and less than 600 C. In a review of the mineralogy of IDPs, it was suggested that the occurrence of other silicates such as enstatite whiskers is consistent with the formation in an early turbulent period of the solar nebula. Experimental confirmation of fundamental chemical and physical processes in a stellar environment, such as vapor phase condensation, nucleation, and growth by annealing, is an important aspect of astrophysical models for the evolution of the Solar System. A detailed comparison of chondritic IDP and carbonaceous chondrite mineralogies shows significant differences between the types of silicate minerals as well as the predominant oxides

  8. Fine particle (PM2.5) personal exposure levels in transport microenvironments, London, UK.

    Science.gov (United States)

    Adams, H S; Nieuwenhuijsen, M J; Colvile, R N; McMullen, M A; Khandelwal, P

    2001-11-12

    In order to investigate a specific area of short-term, non-occupational, human exposure to fine particulate air pollution, measurements of personal exposure to PM2.5 in transport microenvironments were taken in two separate field studies in central London, UK. A high flow gravimetric personal sampling system was used; operating at 16 l min(-1); the sampler thus allowed for sufficient sample mass collection for accurate gravimetric analysis of short-term travel exposure levels over typical single commute times. In total, samples were taken on 465 journeys and 61 volunteers participated. In a multi-transport mode study, carried out over 3-week periods in the winter and in the summer, exposure levels were assessed along three fixed routes at peak and off-peak times of the day. Geometric means of personal exposure levels were 34.5 microg m(-3) (G.S.D.= 1.7, n(s) = 40), 39.0 microg m(-3) (G.S.D. = 1.8, n(s) = 36), 37.7 microg m(-3) (G.S.D. = 1.5, n(s) = 42), and 247.2 microg m(-3) (G.S.D. = 1.3, n(s) = 44) for bicycle, bus, car and Tube (underground rail system) modes, respectively, in the July 1999 (summer) measurement campaign. Corresponding levels in the February 2000 (winter) measurement campaign were 23.5 microg m(-3) (G.S.D. = 1.8, n(s) = 56), 38.9 microg m(-3) (G.S.D. = 2.1, n(s) = 32), 33.7 microg m(-3) (G.S.D. = 2.4, n(s) = 12), and 157.3 microg m(-3) (G.S.D. = 3.3, n(s) = 12), respectively. In a second study, exposure levels were measured for a group of 24 commuters travelling by bicycle, during August 1999, in order to assess how representative the fixed route studies were to a larger commuter population. The geometric mean exposure level was 34.2 microg m(-3) (G.S.D. = 1.9, n(s) = 105). In the fixed-route study, the cyclists had the lowest exposure levels, bus and car were slightly higher, while mean exposure levels on the London Underground rail system were 3-8 times higher than the surface transport modes. There was significant between-route variation

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

    Directory of Open Access Journals (Sweden)

    X. Xu

    2016-05-01

    Full Text Available 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

  10. Impact of smoking on in-vehicle fine particle exposure during driving

    Science.gov (United States)

    Sohn, Hongji; Lee, Kiyoung

    2010-09-01

    Indoor smoking ban in public places can reduce secondhand smoke (SHS) exposure. However, smoking in cars and homes has continued. The purpose of this study was to assess particulate matter less than 2.5 μm (PM 2.5) concentration in moving cars with different window opening conditions. The PM 2.5 level was measured by an aerosol spectrometer inside and outside moving cars simultaneously, along with ultrafine particle (UFP) number concentration, speed, temperature and humidity inside cars. Two sport utility vehicles were used. Three different ventilation conditions were evaluated by up to 20 repeated experiments. In the pre-smoking phase, average in-vehicle PM 2.5 concentrations were 16-17 μg m -3. Regardless of different window opening conditions, the PM 2.5 levels promptly increased when smoking occurred and decreased after cigarette was extinguished. Although only a single cigarette was smoked, the average PM 2.5 levels were 506-1307 μg m -3 with different window opening conditions. When smoking was ceased, the average PM 2.5 levels for 15 min were several times higher than the US National Ambient Air Quality Standard of 35 μg m -3. It took longer than 10 min to reach the level of the pre-smoking phase. Although UFP levels had a similar temporal profile of PM 2.5, the increased levels during the smoking phase were relatively small. This study demonstrated that the SHS exposure in cars with just a single cigarette being smoked could exceed the US EPA NAAQS under realistic window opening conditions. Therefore, the findings support the need for public education against smoking in cars and advocacy for a smoke-free car policy.

  11. 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.

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

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    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.

  13. FREE AND COMBINED AMINO COMPOUNDS IN ATMOSPHERIC FINE PARTICLES (PM2.5) AND FOG WATERS FROM NORTHERN CALIFORNIA. (R825433)

    Science.gov (United States)

    Atmospheric fine particles (PM2.5) 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 PM2.5 and fog waters, the averag...

  14. Influence of airborne-particle abrasion on mechanical properties and bond strength of carbon/epoxy and glass/bis-GMA fiber-reinforced resin posts.

    Science.gov (United States)

    Soares, Carlos Jose; Santana, Fernanda Ribeiro; Pereira, Janaina Carla; Araujo, Tatiana Santos; Menezes, Murilo Souza

    2008-06-01

    Controversy exists concerning the use of fiber-reinforced posts to improve bond strength to resin cement because some precementation treatments can compromise the mechanical properties of the posts. The purpose of this study was to analyze the influence of airborne-particle abrasion on the mechanical properties and microtensile bond strength (MTBS) of carbon/epoxy and glass/bis-GMA fiber-reinforced resin posts. Flexural strength (delta(f)), flexural modulus (E(f)), and stiffness (S) were assessed using a 3-point bending test for glass fiber-reinforced and carbon fiber-reinforced resin posts submitted to airborne-particle abrasion (AB) with 50-microm Al(2)O(3), and for posts without any surface treatment (controls) (n=10). Forty glass fiber (GF) and 40 carbon fiber (CF) posts were submitted to 1 of 4 surface treatments (n=10) prior to MTBS testing: silane (S); silane and adhesive (SA); airborne-particle abrasion with 50-microm Al(2)O(3) and silane (ABS); airborne-particle abrasion, silane, and adhesive (ABSA). Two composite resin restorations (Filtek Z250) with rounded depressions in the lateral face were bilaterally fixed to the post with resin cement (RelyX ARC). Next, the specimen was sectioned with a precision saw running perpendicular to the bonded surface to obtain 10 bonded beam specimens with a cross-sectional area of 1 mm(2). Each beam specimen was tested in a mechanical testing machine (EMIC 2,000 DL), under stress, at a crosshead speed of 0.5 mm/min until failure. Data were analyzed by 2-way ANOVA followed by Tukey HSD test (alpha=.05). Failure patterns of tested specimens were analyzed using scanning electron microscopy (SEM). The 3-point bending test demonstrated significant differences among groups only for the post type factor for flexural strength, flexural modulus, and stiffness. The carbon fiber posts exhibited significantly higher mean flexural strength (P=.001), flexural modulus (P=.003), and stiffness (P=.001) values when compared with glass

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

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    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

  16. Levels, chemical composition and sources of fine aerosol particles (PM1) in an area of the Mediterranean basin

    International Nuclear Information System (INIS)

    Caggiano, Rosa; Macchiato, Maria; Trippetta, Serena

    2010-01-01

    Daily samples of fine aerosol particles (i.e., PM1, aerosol particles with an aerodynamic diameter less than 1.0 μm) were collected in Tito Scalo - Southern Italy - from April 2006 to March 2007. Measurements were performed by means of a low-volume gravimetric sampler, and each PM1 sample was analyzed by means of Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Atomic Absorption Spectrometry (GFAAS and FAAS) techniques in order to determine its content in fourteen trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti and Zn). During the period examined, PM1 daily concentrations ranged between 0.3 μg m -3 and 55 μg m -3 with a mean value of 8 μg m -3 , a standard deviation of 7 μg m -3 and a median value of 6 μg m -3 . As far as PM1 chemical composition is concerned, the mean values of the trace element concentrations decreased in the following order: Ca > Fe > Al > Na > K > Cr > Mg > Pb > Ni ∼ Ti ∼ Zn > Cd ∼ Cu > Mn. Principal Component Analysis (PCA) allowed the identification of three probable PM1 sources: industrial emissions, traffic and re-suspension of soil dust. Moreover, the results of a procedure applied to study the potential long-range transport contribution to PM1 chemical composition, showed that trace element concentrations do not seem to be affected by air mass origin and path. This was probably due to the strong impact of the local emission sources and the lack of the concentration measurements of some important elements and compounds that could better reveal the long-range transport influence on PM1 measurements at ground level.

  17. Levels, chemical composition and sources of fine aerosol particles (PM1) in an area of the Mediterranean basin.

    Science.gov (United States)

    Caggiano, Rosa; Macchiato, Maria; Trippetta, Serena

    2010-01-15

    Daily samples of fine aerosol particles (i.e., PM1, aerosol particles with an aerodynamic diameter less than 1.0mum) were collected in Tito Scalo - Southern Italy - from April 2006 to March 2007. Measurements were performed by means of a low-volume gravimetric sampler, and each PM1 sample was analyzed by means of Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Atomic Absorption Spectrometry (GFAAS and FAAS) techniques in order to determine its content in fourteen trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti and Zn). During the period examined, PM1 daily concentrations ranged between 0.3microgm(-3) and 55microgm(-3) with a mean value of 8 microg m(-3), a standard deviation of 7microgm(-3) and a median value of 6microgm(-3). As far as PM1 chemical composition is concerned, the mean values of the trace element concentrations decreased in the following order: Ca>Fe>Al>Na>K>Cr>Mg>Pb>Ni approximately Ti approximately Zn>Cd approximately Cu>Mn. Principal Component Analysis (PCA) allowed the identification of three probable PM1 sources: industrial emissions, traffic and re-suspension of soil dust. Moreover, the results of a procedure applied to study the potential long-range transport contribution to PM1 chemical composition, showed that trace element concentrations do not seem to be affected by air mass origin and path. This was probably due to the strong impact of the local emission sources and the lack of the concentration measurements of some important elements and compounds that could better reveal the long-range transport influence on PM1 measurements at ground level. Copyright 2009 Elsevier B.V. All rights reserved.

  18. A twelve month study of PM2.5 and PM10 fine particle aerosol composition in the Sydney region using ion beam analysis techniques. Appendix 2

    International Nuclear Information System (INIS)

    Cohen, David D.; Bailey, G.M.; Kondepudi, Ramesh

    1995-01-01

    The accelerator based ion beam (IBA) analysis techniques of PIXE, PIGME, PESA, and RBS have been used to characterise fine particles at selected sites in the Sydney region. The four techniques operating simultaneously provide elemental concentrations on 24 chemical species, including H, Q N, 0, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Ni, Zn, Br and Pb. The total mass and the elemental carbon by laser integrated plate techniques were also measured. A stacked filter system, built by the University of Gent, Belgium and supplied by the IAEA was used to provide fine particle data on PM2.5 and PM10 particles. While a cyclone sampler, built at ANSTO, Lucas Heights, was used to provide data on PM2.5 particles only. The two different types of units were operated along side each other for the whole of 1994 and the results compared. The use of the multi-elemental IBA techniques also allowed for some fine particle source fingerprinting to be performed. (author)

  19. Characterization of SiC based composite materials by the infiltration of ultra-fine SiC particles

    International Nuclear Information System (INIS)

    Lee, J.K.; Lee, S.P.; Byun, J.H.

    2010-01-01

    The fabrication route of SiC materials by the complex compound of ultra-fine SiC particles and oxide additive materials has been investigated. Especially, the effect of additive composition ratio on the characterization of SiC materials has been examined. The characterization of C/SiC composites reinforced with plain woven carbon fabrics was also investigated. The fiber preform for C/SiC composites was prepared by the infiltration of complex mixture into the carbon fabric structure. SiC based composite materials were fabricated by a pressure assisted liquid phase sintering process. SiC materials possessed a good density higher than about 3.0 Mg/m 3 , accompanying the creation of secondary phase by the chemical reaction of additive materials. C/SiC composites also represented a dense morphology in the intra-fiber bundle region, even if this material had a sintered density lower than that of monolithic SiC materials. The flexural strength of SiC materials was greatly affected by the composition ratio of additive materials.

  20. Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis.

    Directory of Open Access Journals (Sweden)

    Pan Wang

    Full Text Available Mounting evidence indicates that early-life exposure to particulate air pollutants pose threats to children's cognitive development, but studies about the neurotoxic effects associated with exposures during adolescence remain unclear. We examined whether exposure to ambient fine particles (PM2.5 at residential locations affects intelligence quotient (IQ during pre-/early- adolescence (ages 9-11 and emerging adulthood (ages 18-20 in a demographically-diverse population (N = 1,360 residing in Southern California. Increased ambient PM2.5 levels were associated with decreased IQ scores. This association was more evident for Performance IQ (PIQ, but less for Verbal IQ, assessed by the Wechsler Abbreviated Scale of Intelligence. For each inter-quartile (7.73 μg/m3 increase in one-year PM2.5 preceding each assessment, the average PIQ score decreased by 3.08 points (95% confidence interval = [-6.04, -0.12] accounting for within-family/within-individual correlations, demographic characteristics, family socioeconomic status (SES, parents' cognitive abilities, neighborhood characteristics, and other spatial confounders. The adverse effect was 150% greater in low SES families and 89% stronger in males, compared to their counterparts. Better understanding of the social disparities and sexual dimorphism in the adverse PM2.5-IQ effects may help elucidate the underlying mechanisms and shed light on prevention strategies.

  1. 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)

  2. Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis

    Science.gov (United States)

    Younan, Diana; Franklin, Meredith; Lurmann, Fred; Wu, Jun; Baker, Laura A.; Chen, Jiu-Chiuan

    2017-01-01

    Mounting evidence indicates that early-life exposure to particulate air pollutants pose threats to children’s cognitive development, but studies about the neurotoxic effects associated with exposures during adolescence remain unclear. We examined whether exposure to ambient fine particles (PM2.5) at residential locations affects intelligence quotient (IQ) during pre-/early- adolescence (ages 9–11) and emerging adulthood (ages 18–20) in a demographically-diverse population (N = 1,360) residing in Southern California. Increased ambient PM2.5 levels were associated with decreased IQ scores. This association was more evident for Performance IQ (PIQ), but less for Verbal IQ, assessed by the Wechsler Abbreviated Scale of Intelligence. For each inter-quartile (7.73 μg/m3) increase in one-year PM2.5 preceding each assessment, the average PIQ score decreased by 3.08 points (95% confidence interval = [-6.04, -0.12]) accounting for within-family/within-individual correlations, demographic characteristics, family socioeconomic status (SES), parents’ cognitive abilities, neighborhood characteristics, and other spatial confounders. The adverse effect was 150% greater in low SES families and 89% stronger in males, compared to their counterparts. Better understanding of the social disparities and sexual dimorphism in the adverse PM2.5–IQ effects may help elucidate the underlying mechanisms and shed light on prevention strategies. PMID:29206872

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

    Directory of Open Access Journals (Sweden)

    Neil E Klepeis

    Full Text Available 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.

  4. Molecular characterization of primary humic-like substances in fine smoke particles by thermochemolysis-gas chromatography-mass spectrometry

    Science.gov (United States)

    Fan, Xingjun; Wei, Siye; Zhu, Mengbo; Song, Jianzhong; Peng, Ping'an

    2018-05-01

    In this study, the molecular structures of primary humic-like substances (HULIS) in fine smoke particles emitted from the combustion of biomass materials (including rice straw, corn straw, and pine branches) and coal, and atmospheric HULIS were determined by off-line tetramethylammonium hydroxide thermochemolysis coupled with gas chromatography and mass spectrometry (TMAH-GC/MS). A total of 89 pyrolysates were identified by the thermochemolysis of primary and atmospheric HULIS. The main groups were polysaccharide derivatives, N-containing compounds, lignin derivatives, aromatic acid methyl ester, aliphatic acid methyl ester, and diterpenoid derivatives. Both the type and distribution of pyrolysates among primary HULIS were comparable to those in atmospheric HULIS. This indicates that primary HULIS from combustion processes are important contributors to atmospheric HULIS. Some distinct differences were also observed. The aromatic compounds, including lignin derivatives and aromatic acid methyl ester, were the major pyrolysates (53.0%-84.9%) in all HULIS fractions, suggesting that primary HULIS significantly contributed aromatic structures to atmospheric HULIS. In addition, primary HULIS from biomass burning (BB) contained a relatively high abundance of lignin and polysaccharide derivatives, which is consistent with the large amounts of lignin and cellulose structures contained in biomass materials. Aliphatic acid methyl ester and benzyl methyl ether were prominent pyrolysates in atmospheric HULIS. Moreover, some molecular markers of specific sources were obtained from the thermochemolysis of primary and atmospheric HULIS. For example, polysaccharide derivatives, pyridine and pyrrole derivatives, and lignin derivatives can be used as tracers of fresh HULIS emitted from BB. Diterpenoid derivatives are important markers of HULIS from pine wood combustion sources. Finally, the differences in pyrolysate types and the distributions between primary and atmospheric HULIS

  5. Multi-scale analysis of the effect of nano-filler particle diameter on the physical properties of CAD/CAM composite resin blocks.

    Science.gov (United States)

    Yamaguchi, Satoshi; Inoue, Sayuri; Sakai, Takahiko; Abe, Tomohiro; Kitagawa, Haruaki; Imazato, Satoshi

    2017-05-01

    The objective of this study was to assess the effect of silica nano-filler particle diameters in a computer-aided design/manufacturing (CAD/CAM) composite resin (CR) block on physical properties at the multi-scale in silico. CAD/CAM CR blocks were modeled, consisting of silica nano-filler particles (20, 40, 60, 80, and 100 nm) and matrix (Bis-GMA/TEGDMA), with filler volume contents of 55.161%. Calculation of Young's moduli and Poisson's ratios for the block at macro-scale were analyzed by homogenization. Macro-scale CAD/CAM CR blocks (3 × 3 × 3 mm) were modeled and compressive strengths were defined when the fracture loads exceeded 6075 N. MPS values of the nano-scale models were compared by localization analysis. As the filler size decreased, Young's moduli and compressive strength increased, while Poisson's ratios and MPS decreased. All parameters were significantly correlated with the diameters of the filler particles (Pearson's correlation test, r = -0.949, 0.943, -0.951, 0.976, p CAD/CAM CR blocks can be enhanced by loading silica nanofiller particles of smaller diameter. CAD/CAM CR blocks by using smaller silica nano-filler particles have a potential to increase fracture resistance.

  6. Personal exposure to fine particles (PM2.5) and respiratory inflammation of common residents in Hong Kong.

    Science.gov (United States)

    Fan, Zhanlan; Pun, Vivian C; Chen, Xiao-Cui; Hong, Qiu; Tian, Linwei; Ho, Steven Sai-Hang; Lee, Shun-Cheng; Tse, Lap Ah; Ho, Kin-Fai

    2018-02-17

    Given the lack of research on the personal exposure to fine particles (PM 2.5 ) in Hong Kong, we examined the association between short-term personal exposure to PM 2.5 and their constituents and inflammation in exhaled breath in a sample of healthy adult residents. Forty-six participants underwent personal PM 2.5 monitoring for averagely 6 days to obtain 276 samples. Fractional exhaled nitric oxide (FeNO), a biomarker of inflammation in exhaled breath, was measured at the end of each 24-h personal monitoring. PM 2.5 chemical constituents, including organic carbon, elemental carbon, 16 polycyclic aromatic hydrocarbons (PAHs), and 6 phthalate esters, were speciated from the personal samples collected. A mixed-effects model was used to estimate the association of PM 2.5 and their constituents with FeNO. The comparison was also made with parallel analyses using ambient concentrations. Personal exposures to PM 2.5 (28.1 ± 23.3 μg/m 3 ) were higher than the ambient levels (13.3 ± 6.4 μg/m 3 ) monitored by stations. The composition profile and personal-to-ambient concentration ratio varied among subjects with different occupations. An interquartile range (IQR) change in personal exposure to PM 2.5 was positively associated with 12.8% increase in FeNO (95% confidence interval, CI: 5.5-20.7%), while nil association was found for ambient PM 2.5 . Among the constituents measured, only the carcinogenic PAHs were significantly associated with 12% increase in FeNO responses (95% CI, 0.0-25.6%). In conclusion, our study provides the first understanding about personal exposure to PM 2.5 and possible sources in Hong Kong. The results also showed that personal exposure to PM 2.5 and c-PAHs were linked to increased FeNO levels among healthy adults. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. 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.

  8. Water-soluble ions in nano/ultrafine/fine/coarse particles collected near a busy road and at a rural site

    International Nuclear Information System (INIS)

    Lin, C.-C.; Chen, S.-J.; Huang, K.-L.; Lee, W.-J.; Lin, W.-Y.; Liao, C.-J.; Chaung, H.-C.; Chiu, C.-H.

    2007-01-01

    This study investigated water-soluble ions in the sized particles (particularly nano (PM 0.01-0.056 )/ultrafine (PM 0.01-0.1 )) collected using MOUDI and Nano-MOUDI samplers near a busy road site and at a rural site. The analytical results demonstrate that nano and coarse particles exhibited the highest (16.3%) and lowest (8.37%) nitrate mass ratios, respectively. The mass ratio of NO 3 - was higher than that of SO 4 2- in all the sized particles at the traffic site. The secondary aerosols all displayed trimodal distributions. The aerosols in ultrafine particles collected at the roadside site exhibited Aitken mode distributions indicating they were of local origin. This finding was not observed for those ultrafine particles collected at the rural site. The mass median diameters (MMDs) of the nano, ultrafine, and fine particles were smaller at the traffic site than at the rural site, possibly related to the contribution of mobile engine emissions. - NO 3 - > SO 4 2- in mass ratio, different from common observations in rural areas, was found in (particularly the nano) traffic-associated particles

  9. Novel processing of bioglass ceramics from silicone resins containing micro- and nano-sized oxide particle fillers.

    Science.gov (United States)

    Fiocco, L; Bernardo, E; Colombo, P; Cacciotti, I; Bianco, A; Bellucci, D; Sola, A; Cannillo, V

    2014-08-01

    Highly porous scaffolds with composition similar to those of 45S5 and 58S bioglasses were successfully produced by an innovative processing method based on preceramic polymers containing micro- and nano-sized fillers. Silica from the decomposition of the silicone resins reacted with the oxides deriving from the fillers, yielding glass ceramic components after heating at 1000°C. Despite the limited mechanical strength, the obtained samples possessed suitable porous architecture and promising biocompatibility and bioactivity characteristics, as testified by preliminary in vitro tests. © 2013 Wiley Periodicals, Inc.

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

    Directory of Open Access Journals (Sweden)

    A. Vara-Vela

    2016-01-01

    Full Text Available 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

  11. "Depth-profiling" and quantitative characterization of the size, composition, shape, density, and morphology of fine particles with SPLAT, a single-particle mass spectrometer.

    Science.gov (United States)

    Zelenyuk, Alla; Yang, Juan; Song, Chen; Zaveri, Rahul A; Imre, Dan

    2008-01-31

    A significant fraction of atmospheric particles are composed of inorganic substances that are mixed or coated with organic compounds. The properties and behavior of these particles depend on the internal composition and arrangement of the specific constituents in each particle. It is important to know which constituent is on the surface and whether it covers the particle surface partially or entirely. We demonstrate here an instrument consisting of an ultrasensitive single-particle mass spectrometer coupled with a differential mobility analyzer to quantitatively measure in real time individual particle composition, size, density, and shape and to determine which substance is on the surface and whether it entirely covers the particle. For this study, we use NaCl particles completely coated with liquid dioctyl phthalate to generate spherical particles, and NaCl particles partially coated with pyrene, a solid poly aromatic hydrocarbon, to produce aspherical particles with pyrene nodules and an exposed NaCl core. We show that the behavior of the mass spectral intensities as a function of laser fluence yields information that can be used to determine the morphological distribution of individual particle constituents.

  12. Electrode geometry effects on the collection efficiency of submicron and ultra-fine dust particles in spike-plate electrostatic precipitators

    International Nuclear Information System (INIS)

    Brocilo, D; Podlinski, J; Chang, J S; Mizeraczyk, J; Findlay, R D

    2008-01-01

    The collection efficiency of electrostatic precipitators for the submicron particles ranging from 0.1 to 1 μm and ultrafine particles smaller than 0. lμm is below the requirements of new PM2.5 emission regulations. In this work, numerical and experimental studies were conducted to examine the effect of discharge and collecting electrode geometries on the ion density and electric field profiles and consequently their effect on the particle surface charge and collection efficiency. The collection efficiency prediction was based on a modified Deutsche's equation after calculation of three dimensional electric field and ion density profiles. Whereas, the particle surface charge was obtained from diffusion and field charging models. Results show that the collection efficiency of fine particles for the spike-type discharge electrode when compared to the conventional wire-type was improved. Experimental validations were conducted on a bench scale electrostatic precipitator for total and partial collection efficiency of particles ranging in size from 0.01 to 20 μm and the results indicated that the model can be effectively applied for prototype design, modification, and scale-up of collecting and discharge electrodes.

  13. Co-formation of hydroperoxides and ultra-fine particles during the reactions of ozone with a complex VOC mixture under simulated indoor conditions

    DEFF Research Database (Denmark)

    Fan, Z.H.; Weschler, Charles J.; Han, IK

    2005-01-01

    In this study we examined the co-formation of hydrogen peroxide and other hydroperoxides (collectively presented as H2O2*) as well as submicron particles, including ultra-fine particles (UFP), resulting from the reactions of ozone (O-3) with a complex mixture of volatile organic compounds (VOCs...... higher than typical indoor levels. When O-3 was added to a 25-m(3) controlled environmental facility (CEF) containing the 23 VOC mixture, both H2O2* and submicron particles were formed. The 2-h average concentration of H2O2* was 1.89 +/- 0.30ppb, and the average total particle number concentration was 46...... to achieve saturated concentrations of the condensable organics. When the 2 terpenes were removed from the O-3/23 VOCs mixture, no H2O2* or particles were formed, indicating that the reactions of O-3 With the two terpenes were the key processes contributing to the formation of H2O2* and submicron particles...

  14. 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

  15. Evaluation of Methods for Physical Characterization of the Fine Particle Emissions from Two Residential Wood Combustion Appliances

    Science.gov (United States)

    The fine particulate matter (PM) emissions from a U. S. certified non-catalytic wood stove and a zero clearance fireplace burning Quercus rubra L. (northern red oak) and Pseudotsuga menziesii (Douglas fir) cordwood each at two different moisture levels were determined. Emission t...

  16. Aerosol pH buffering in the southeastern US: Fine particles remain highly acidic despite large reductions in sulfate

    Science.gov (United States)

    Weber, R. J.; Guo, H.; Russell, A. G.; Nenes, A.

    2015-12-01

    pH is a critical aerosol property that impacts many atmospheric processes, including biogenic secondary organic aerosol formation, gas-particle phase partitioning, and mineral dust or redox metal mobilization. Particle pH has also been linked to adverse health effects. Using a comprehensive data set from the Southern Oxidant and Aerosol Study (SOAS) as the basis for thermodynamic modeling, we have shown that particles are currently highly acidic in the southeastern US, with pH between 0 and 2. Sulfate and ammonium are the main acid-base components that determine particle pH in this region, however they have different sources and their concentrations are changing. Over 15 years of network data show that sulfur dioxide emission reductions have resulted in a roughly 70 percent decrease in sulfate, whereas ammonia emissions, mainly link to agricultural activities, have been largely steady, as have gas phase ammonia concentrations. This has led to the view that particles are becoming more neutralized. However, sensitivity analysis, based on thermodynamic modeling, to changing sulfate concentrations indicates that particles have remained highly acidic over the past decade, despite the large reductions in sulfate. Furthermore, anticipated continued reductions of sulfate and relatively constant ammonia emissions into the future will not significantly change particle pH until sulfate drops to clean continental background levels. The result reshapes our expectation of future particle pH and implies that atmospheric processes and adverse health effects linked to particle acidity will remain unchanged for some time into the future.

  17. Multi-criteria ranking and receptor modelling of airborne fine particles at three sites in the Pearl River Delta region of China.

    Science.gov (United States)

    Friend, Adrian J; Ayoko, Godwin A; Guo, Hai

    2011-01-15

    The multi-criteria decision making methods, Preference Ranking Organization METHods for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA), and the two-way Positive Matrix Factorization (PMF) receptor model were applied to airborne fine particle compositional data collected at three sites in Hong Kong during two monitoring campaigns held from November 2000 to October 2001 and November 2004 to October 2005. PROMETHEE/GAIA indicated that the three sites were worse during the later monitoring campaign, and that the order of the air quality at the sites during each campaign was: rural site>urban site>roadside site. The PMF analysis on the other hand, identified 6 common sources at all of the sites (diesel vehicle, fresh sea salt, secondary sulphate, soil, aged sea salt and oil combustion) which accounted for approximately 68.8±8.7% of the fine particle mass at the sites. In addition, road dust, gasoline vehicle, biomass burning, secondary nitrate, and metal processing were identified at some of the sites. Secondary sulphate was found to be the highest contributor to the fine particle mass at the rural and urban sites with vehicle emission as a high contributor to the roadside site. The PMF results are broadly similar to those obtained in a previous analysis by PCA/APCS. However, the PMF analysis resolved more factors at each site than the PCA/APCS. In addition, the study demonstrated that combined results from multi-criteria decision making analysis and receptor modelling can provide more detailed information that can be used to formulate the scientific basis for mitigating air pollution in the region. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Deposition of crystalline hydroxyapatite nano-particle on zirconia ceramic: a potential solution for the poor bonding characteristic of zirconia ceramics to resin cement.

    Science.gov (United States)

    Azari, Abbas; Nikzad, Sakineh; Yazdani, Arash; Atri, Faezeh; Fazel Anvari-Yazdi, Abbas

    2017-07-01

    The poor bonding strength of zirconia to different dental substrates is one of the challenging issues in restorative dentistry. Hydroxyapatite is an excellent biocompatible material with fine bonding properties. In this study, it was hypothesized that hydroxyapatite coating on zirconia would improve its bond strength. Forty-five zirconia blocks were prepared and randomly divided into three groups: hydroxyapatite coating, sandblasting, and no preparation (control). The blocks were bonded to cement and the micro-shear bond strength was measured following load application. The bond strength values were analyzed with the Kruskal-Wallis test in 3 groups and paired comparisons were made using the Mann-Whitney U test. The failure patterns of the specimens were studied by a stereomicroscope and a scanning electron microscope and then analyzed by the chi-square test (significance level = 0.05). Deposition of hydroxyapatite on the zirconia surface significantly improved its bond strength to the resin cement in comparison with the control specimens (p < 0.0001). Also, the bond strength was similar to the sandblasted group (p = 0.34). The sandblasted and control group only showed adhesive failure, but the hydroxyapatite coated group had mixed failures, indicating the better quality of bonding (p < 0.0001). As a final point, hydroxyapatite coating on the zirconia surface improved the bond strength quality and values.

  19. Resuspension of coal and coal/municipal sewage sludge combustion generated fine particles for inhalation health effects studies

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Art; Wendt, Jost O.L. [Department of Chemical and Environmental Engineering, University of Arizona, 85721 Tucson, AZ (United States); Cenni, Roberta [Institut fuer Verfahrenstechnik und Dampfkesselwesen, Universitaet Stuttgart, Stuttgart (Germany); Young, R. Scott; Witten, Mark L. [Lung Injury Laboratory, Department of Pediatrics, Arizona Health Sciences Center, 85721 Tucson, AZ (United States)

    2002-03-27

    Airborne particulate matter (PM) is an important environmental issue because of its association with acute respiratory distress in humans, although the specific particle characteristics that cause lung damage have yet to be identified. Particle size, acid aerosols, water-soluble transition metals (e.g. Cu, Fe, V, Ni and Zn), polyaromatic hydrocarbons, and particle composition are the focus of several popular hypotheses addressing respiratory distress. All of the above mentioned characteristics are contained in PM generated from the combustion of both pulverized coal, and biomass, including dried municipal sewage sludge (MSS). In this investigation, we report results from collaborative interdisciplinary research on the inhalation health risks caused by particles emitted from the co-combustion of municipal sewage sludge (MSS) and coal. A solid particle resuspension system was implemented to resuspend ash particles. Mice were exposed to resuspended coal and MSS/coal ash particles. Mice exposed to MSS/coal ash particulate demonstrated significant increases in lung permeability, a marker of the early stages of pathological lung injury, while the mice exposed to coal-only ash did not. These results show that the composition of particles actually inhaled is important in determining lung damage. Zinc was significantly more concentrated in the MSS/coal ash than coal ash particles and the pH of these particles did not differ significantly. Specifically, an MSS/coal mixture, when burned, emits particles that may cause significantly more lung damage than coal alone, and that consequently, the use of MSS as a 'green', CO{sub 2}-neutral replacement fuel should be carefully considered.

  20. LA-ICP-MS of rare earth elements concentrated in cation-exchange resin particles for origin attribution of uranium ore concentrate.

    Science.gov (United States)

    Asai, Shiho; Limbeck, Andreas

    2015-04-01

    Rare earth elements (REE) concentrated on cation-exchange resin particles were measured with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to obtain chondrite-normalized REE plots. The sensitivity of REE increased in ascending order of the atomic number, according to the sensitivity trend in pneumatic nebulization ICP-MS (PN-ICP-MS). The signal intensities of REE were nearly proportional to the concentrations of REE in the immersion solution used for particle-preparation. Minimum measurable concentration calculated from the net signals of REE was approximately 1 ng/g corresponding to 0.1 ng in the particle-preparation solution. In LA analysis, formation of oxide and hydroxide of the light REE and Ba which causes spectral interferences in the heavy REE measurement was effectively attenuated due to the solvent-free measurement capability, compared to conventional PN-ICP-MS. To evaluate the applicability of the proposed method, the REE-adsorbed particles prepared by immersing them in a U-bearing solution (commercially available U standard solution) were measured with LA-ICP-MS. Aside from the LA analysis, each concentration of REE in the same U standard solution was determined with conventional PN-ICP-MS after separating REE by cation-exchange chromatography. The concentrations of REE were ranging from 0.04 (Pr) to 1.08 (Dy) μg/g-U. The chondrite-normalized plot obtained through LA-ICP-MS analysis of the U standard sample exhibited close agreement with that obtained through the PN-ICP-MS of the REE-separated solution within the uncertainties. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Characteristics of resin floc dispersion of anion and cation exchange resin in precoat filter using powdered ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Tetsurou (Nitto Denko Corp., Ibaraki, Osaka (Japan)); Sawa, Toshio; Shindoh, Toshikazu

    1989-09-01

    The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of resin floc dispersion. The factors related to resin floc dispersion of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index in addition to the measurement of physical, chemical and electrochemical properties of powdered ion exchange resin. The effect of adsorption of iron oxide and polymer electrolyte and of ion exchange were determined. In addition, considered floc dispersion with adsorbing iron oxide, it was assumed that the amount and filling ratio of resin floc were related to summation and multiplication of surface electric charge respectively. An experimental expression was obtained for simulation of the change of specific settle volume of resin floc by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author).

  2. Characteristics of resin floc dispersion of anion and cation exchange resin in precoat filter using powdered ion exchange resin

    International Nuclear Information System (INIS)

    Adachi, Tetsurou; Sawa, Toshio; Shindoh, Toshikazu.

    1989-01-01

    The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of resin floc dispersion. The factors related to resin floc dispersion of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index in addition to the measurement of physical, chemical and electrochemical properties of powdered ion exchange resin. The effect of adsorption of iron oxide and polymer electrolyte and of ion exchange were determined. In addition, considered floc dispersion with adsorbing iron oxide, it was assumed that the amount and filling ratio of resin floc were related to summation and multiplication of surface electric charge respectively. An experimental expression was obtained for simulation of the change of specific settle volume of resin floc by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author)

  3. and phenol–formaldehyde resin

    Indian Academy of Sciences (India)

    formaldehyde resin (PFR) modified with tetraethylorthosilicate are investigated in detail. The chemical synthesis of PFR, its modification with nanometer- sized SiO2 particles created by sol–gel method and subsequent coating, enables a preparation of ...

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

    Science.gov (United States)

    Lamorena, Rheo B; Jung, Sang-Guen; Bae, Gwi-Nam; Lee, Woojin

    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 (4.4-168nm) was observed in the presence of ozone. Carboxylic acids were also observed to form during the reactions (i.e. formic acid at 0.170ppm and acetic acid at 0.260ppm). 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 440min, 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.

  5. Two-Step Single Particle Mass Spectrometry for On-Line Monitoring of Polycyclic Aromatic Hydrocarbons Bound to Ambient Fine Particulate Matter

    Science.gov (United States)

    Zimmermann, R.; Bente, M.; Sklorz, M.

    2007-12-01

    Polycyclic aromatic hydrocarbons (PAH) are formed as trace products in combustion processes and are emitted to the atmosphere. Larger PAH have low vapour pressure and are predominantly bound to the ambient fine particulate matter (PM). Upon inhalation, PAH show both, chronic human toxicity (i.e. many PAH are potent carcinogens) as well as acute human toxicity (i.e. inflammatory effects due to oxi-dative stress) and are discussed to be relevant for the observed health effect of ambient PM. Therefore a better understanding of the occurrence, dynamics and particle size dependence of particle bound-PAH is of great interest. On-line aerosol mass spectrometry in principle is the method of choice to investigate the size resolved changes in the chemical speciation of particles as well the status of internal vs. external mixing of chemical constituents. However the present available aerosol mass spectrometers (ATOFMS and AMS) do not allow detection of PAH from ambient air PM. In order to allow a single particle based monitoring of PAH from ambient PM a new single particle laser ionisation mass spectrometer was built and applied. The system is based on ATOFMS principle but uses a two- step photo-ionization. A tracked and sized particle firstly is laser desorbed (LD) by a IR-laser pulse (CO2-laser, λ=10.2 μm) and subsequently the released PAH are selectively ionized by an intense UV-laser pulse (ArF excimer, λ=248 nm) in a resonance enhanced multiphoton ionisation process (REMPI). The PAH-ions are detected in a time of flight mass spectrometer (TOFMS). A virtual impactor enrichment unit is used to increase the detection frequency of the ambient particles. With the current inlet system particles from about 400 nm to 10 μm are accessible. Single particle based temporal profiles of PAH containing particles ion (size distribution and PAH speciation) have been recorded in Oberschleissheim, Germany from ambient air. Furthermore profiles of relevant emission sources (e

  6. An evaluation of the impact of flooring types on exposures to fine and coarse particles within the residential micro-environment using CONTAM.

    Science.gov (United States)

    Bramwell, Lisa; Qian, Jing; Howard-Reed, Cynthia; Mondal, Sumona; Ferro, Andrea R

    2016-01-01

    Typical resuspension activities within the home, such as walking, have been estimated to contribute up to 25% of personal exposures to PM10. Chamber studies have shown that for moderate walking intensities, flooring type can impact the rate at which particles are re-entrained into the air. For this study, the impact of residential flooring type on incremental average daily (24 h) time-averaged exposure was investigated. Distributions of incremental time-averaged daily exposures to fine and coarse PM while walking within the residential micro-environment were predicted using CONTAM, the multizone airflow and contaminant transport program of the National Institute of Standards and Technology. Knowledge of when and where a person was walking was determined by randomly selecting 490 daily diaries from the EPA's consolidated human activity database (CHAD). On the basis of the results of this study, residential flooring type can significantly impact incremental time-averaged daily exposures to coarse and fine particles (α=0.05, Pmicro-environment contributed 6-72% of time-averaged daily exposures to PM10.

  7. Satellite-Based Estimates of Long-Term Exposure to Fine Particles and Association with Mortality in Elderly Hong Kong Residents.

    Science.gov (United States)

    Wong, Chit Ming; Lai, Hak Kan; Tsang, Hilda; Thach, Thuan Quoc; Thomas, G Neil; Lam, Kin Bong Hubert; Chan, King Pan; Yang, Lin; Lau, Alexis K H; Ayres, Jon G; Lee, Siu Yin; Chan, Wai Man; Hedley, Anthony J; Lam, Tai Hing

    2015-11-01

    A limited number of studies on long-term effects of particulate matter with aerodynamic diameter National Aeronautics and Space Administration (NASA) satellite data. We used Cox regression models to calculate hazard ratios (HRs) of mortality associated with PM2.5. Mortality HRs per 10-μg/m3 increase in PM2.5 were 1.14 (95% CI: 1.07, 1.22) for all natural causes, 1.22 (95% CI: 1.08, 1.39) for cardiovascular causes, 1.42 (95% CI: 1.16, 1.73) for ischemic heart disease, 1.24 (95% CI: 1.00, 1.53) for cerebrovascular disease, and 1.05 (95% CI: 0.90, 1.22) for respiratory causes. Our methods in using NASA satellite data provide a readily accessible and affordable approach to estimation of a sufficient range of individual PM2.5 exposures in a single city. This approach can expand the capacity to conduct environmental accountability studies in areas with few measurements of fine particles. Wong CM, Lai HK, Tsang H, Thach TQ, Thomas GN, Lam KB, Chan KP, Yang L, Lau AK, Ayres JG, Lee SY, Chan WM, Hedley AJ, Lam TH. 2015. Satellite-based estimates of long-term exposure to fine particles and association with mortality in elderly Hong Kong residents. Environ Health Perspect 123:1167-1172; http://dx.doi.org/10.1289/ehp.1408264.

  8. 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.

  9. 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

  10. 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

  11. Comparative study of the performance of columns packed with several new fine silica particles. Would the external roughness of the particles affect column properties?

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2007-09-28

    We measured and compared the characteristics and performance of columns packed with particles of five different C(18)-bonded silica, 3 and 5 microm Luna, 3 microm Atlantis, 3.5 microm Zorbax, and 2.7 microm Halo. The average particle size of each material was derived from the SEM pictures of 200 individual particles. These pictures contrast the irregular morphology of the external surface of the Zorbax and Halo particles and the smooth surface of the Luna and Atlantis particles. In a wide range of mobile phase velocities (from 0.010 to 3 mL/min) and at ambient temperature, we measured the first and second central moments of the peaks of naphthalene, insulin, and bovine serum albumin (BSA). These moments were corrected for the contributions of the extra-column volumes to calculate the reduced HETPs. The C-terms of naphthalene and insulin are largest for the Halo and Zorbax materials and the A-term smallest for the Halo-packed column. The Halo column performs the best for the low molecular weight compound naphthalene (minimum reduced HETP, 1.4) but is not as good as the Atlantis or Luna columns for the large molecular weight compound insulin. The Zorbax column is the least efficient column because of its large C-term. The lowest sample diffusivity through these particles, alone, does not account for the results. It is most likely that the roughness of the external surface of the Halo and Zorbax particles limit the performance of these columns at high flow rates generating an unusually high film mass transfer resistance.

  12. NMR-based metabolomics to determine acute inhalation effects of nano- and fine-sized ZnO particles in the rat lung.

    Science.gov (United States)

    Lee, Sheng-Han; Wang, Ting-Yi; Hong, Jia-Huei; Cheng, Tsun-Jen; Lin, Ching-Yu

    2016-09-01

    Zinc oxide (ZnO) particles induce acute occupational inhalation illness in humans and rats. However, the possible molecular mechanisms of ZnO particles on the respiratory system remain unclear. In this study, metabolic responses of the respiratory system of rats inhaled ZnO particles were investigated by a nuclear magnetic resonance (NMR)-based metabolomic approach. Male Sprague-Dawley rats were treated with a series of doses of nano-sized (35 nm) or fine-sized (250 nm) ZnO particles. The corresponding control groups inhaled filtered air. After 24 h, bronchoalveolar lavage fluid (BALF) and lung tissues were collected, extracted and prepared for (1)H and J-resolved NMR analysis, followed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). PCA and PLSDA models from analysis of BALF and hydrophilic lung NMR spectra demonstrated that dose response trends were restricted to the 250 nm ZnO particle exposure group and were not observed in the 35 nm ZnO particle exposure group. Increased isoleucine and valine, as well as decreased acetate, trimethylamine n-oxide, taurine, glycine, formate, ascorbate and glycerophosphocholine, were recorded in the BALF of rats treated with moderate and high dose 250 nm ZnO exposures. Decreases in taurine and glucose, as well as an increase of phosphorylcholine-containing lipids and fatty acyl chains, were detected in the lung tissues from 250 nm ZnO-treated rats. These metabolic changes may be associated with cell anti-oxidation, energy metabolism, DNA damage and membrane stability. We also concluded that a metabolic approach provides more complete measurements and suggests potential molecular mechanisms of adverse effects.

  13. Surface areas of turbostratic graphitic carbons prepared from a resin using nickel particles, 20 nm, as graphitization catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Oya, A.; Inoue, E.; Otani, S.; Marsh, H.

    1981-11-01

    Nickel particles were used to graphitize catalytically a non-graphitizing carbon to create a turbostratic graphitic material called the T/SUB/s-component. This method was examined by X-ray diffraction. Coals on heat treatment to temperatures >1270 K form T/SUB/s-component carbons. Therefore, considerations of the properties of the T/SUB/s-component carbon may have relevance to considerations of the operational performances of blast furnace coke. (22 refs.)

  14. 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 (UFP<100nm) and accumulation mode particles (AMP 100-665nm). Four commercial cooking 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 PM 2.5 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 PM 1.0 /PM 2.5 and PM 2.5 /PM 10 at peak emission time are around 0.51-0.66 and 0.23-0.29. After 15min naturally deposition, decay rates of PM 1.0 , PM 2.5 and PM 10 are 13.3%-29.8%, 20.1%-33.9% and 41.2%-54.7%, which manifest that PM 1.0 is quite hard to decay than larger particles, PM 2.5 and PM 10 . 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.

  15. Fine and ultrafine particle exposures on 73 trips by car to 65 non-smoking restaurants in the San Francisco Bay Area.

    Science.gov (United States)

    Ott, W R; Wallace, L A; McAteer, J M; Hildemann, L M

    2017-01-01

    A number of studies indicate cooking is a major source of exposure to particulate matter, but few studies have measured indoor air pollution in restaurants, where cooking predominates. We made 73 visits by car to 65 different non-smoking restaurants in 10 Northern California towns while carrying portable continuous monitors that unobtrusively measured ultrafine (down to 10 nm) and fine (PM 2.5 ) particles to characterize indoor restaurant exposures, comparing them with exposures in the car. The mean ultrafine number concentrations in the restaurants on dinner visits averaging 1.4 h was 71 600 particles/cm 3 , or 4.3 times the mean concentration on car trips, and 12.3 times the mean background concentration in the residence. Restaurants that cooked dinner in the same room as the patrons had higher ultrafine concentrations than restaurants with separate kitchens. Restaurant PM 2.5 mass concentrations averaged 36.3 μg/m 3 , ranging from 1.5 to 454 μg/m 3 , but were relatively low on most visits: 43% of the indoor means were below 10 μg/m 3 and 66% were below 20 μg/m 3 , with 5.5% above 100 μg/m 3 . Exposure to fine and ultrafine particles when visiting a restaurant exceeded the exposure a person received while traveling by car to and from the restaurant. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Studies of transformation and particle-binding of resin acids during oxidative treatment of effluent from two New Zealand pulp mills.

    Science.gov (United States)

    Kanber, S A; Langdon, A G; Wilkins, A L

    2008-02-01

    Reactor studies of aerobic degradation of effluent from the first and last ponds of the treatment system of two New Zealand pulp and paper mills indicated that filterable BOD(5), resin acids and transformed resin acids, free and bound, degraded at similar rates. During oxidative treatment the resin acids of untreated effluent became increasingly bound to particulate material and a sediment high in abiet-13-enoic acid was formed.

  17. Adsorption behaviors of surface active reagents on barium ferrite magnetic fine particles; Barium ferrite jisei biryushi eno hymen shorizai kyuchaku

    Energy Technology Data Exchange (ETDEWEB)

    Kudo, M.; Otani, T.; Masuko, T. [Yamagata University, Yamagata (Japan). Faculty of Engineering

    1998-06-10

    The adsorption mode of lecithin (dioleoylphosphatidylcholine) or [3-(methacryloyloxy)propyl] trimethoxysilane (MPS) onto barium ferrite magnetic particles has been investigated by measurements of changes in solution concentration of the surfactant. Both adsortion isotherms of the surface active reagents on barium ferrite particles indicated to be of the Langmuir type. The occupied areas per one molecule on the surface of barium ferrite particles were estimated to be about 70 angstrom{sup 2}/molecule for lecithin and 22 angstrom{sup 2}/molecule for MPS at their saturated adsorption. In X-ray photoelectron spectroscopy (XPS) measurements for the adsorbed lecithin layer, the peak position in the binding energy distribution for the P (2p) photoelectron was observed to shift into slightly higher values with increasing amount of adsorbed lecithin. This implies that dipole-dipole interactions among the lecithin molecules become stronger because of increased high molecular packing in the adsorption layers. However, the peak position for the Si (2p) photoelectron remains almost unchanged due to slight interaction among the adsorbing functional groups onto the particles. 16 refs., 16 figs., 3 tabs.

  18. Measurement of Fine Particles From Mobile and Stationary Sources, and Reducing the Air Conditioner Power Consumption in Hybrid Electric Vehicles

    Science.gov (United States)

    Brewer, Eli Henry

    We study the PM2.5and ultrafine exhaust emissions from a new natural gas-fired turbine power facility to better understand air pollution in California. To characterize the emissions from new natural gas turbines, a series of tests were performed on a GE LMS100 gas turbine. These tests included PM2.5 and wet chemical tests for SO2/SO 3 and NH3, as well as ultrafine (less than 100 nm in diameter) particulate matter measurements. The turbine exhaust had an average particle number concentration that was 2.3x103 times higher than ambient air. The majority of these particles were nanoparticles; at the 100 nm size, stack particle concentrations were about 20 times higher than ambient, and increased to 3.9x104 times higher on average in the 2.5 - 3 nm particle size range. This study also found that ammonia emissions were higher than expected, but in compliance with permit conditions. This was possibly due to an ammonia imbalance entering the catalyst, some flue gas bypassing the catalyst, or not enough catalyst volume. SO3 accounted for an average of 23% of the total sulfur oxides emissions measured. Some of the SO3 is formed in the combustion process, it is likely that the majority formed as the SO2 in the combustion products passed across the oxidizing CO catalyst and SCR catalyst. The 100 MW turbine sampled in this study emitted particle loadings similar to those previously measured from turbines in the SCAQMD area, however, the turbine exhaust contained far more particles than ambient air. The power consumed by an air conditioner accounts for a significant fraction of the total power used by hybrid and electric vehicles especially during summer. This study examined the effect of recirculation of cabin air on power consumption of mobile air conditioners both in-lab and on-road. Real time power consumption and vehicle mileage were recorded by an On Board Diagnostic monitor and carbon balance method. Vehicle mileage improved with increased cabin air recirculation. The

  19. 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

    2017-10-30

    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 (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 (T g ) 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 T g 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 T g . Copyright © 2017 Elsevier B.V. All rights reserved.

  20. 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

  1. Outdoor fine and ultrafine particle measurements at six bus stops with smoking on two California arterial highways--results of a pilot study.

    Science.gov (United States)

    Ott, Wayne R; Acevedo-Bolton, Viviana; Cheng, Kai-Chung; Jiang, Ruo-Ting; Klepeis, Neil E; Hildemann, Lynn M

    2014-01-01

    As indoor smoking bans have become widely adopted, some U.S. communities are considering restricting smoking outdoors, creating a need for measurements of air pollution near smokers outdoors. Personal exposure experiments were conducted with four to five participants at six sidewalk bus stops located 1.5-3.3 m from the curb of two heavily traveled California arterial highways with 3300-5100 vehicles per hour. At each bus stop, a smoker in the group smoked a cigarette. Gravimetrically calibrated continuous monitors were used to measure fine particle concentrations (aerodynamic diameter bus stop, ultrafine particles (UFP), wind speed, temperature, relative humidity, and traffic counts were also measured. For 13 cigarette experiments, the mean PM2.5 personal exposure of the nonsmoker seated 0.5 m from the smoker during a 5-min cigarette ranged from 15 to 153 microg/m3. Of four persons seated on the bench, the smoker received the highest PM2.5 breathing-zone exposure of 192 microg/m3. There was a strong proximity effect: nonsmokers at distances 0.5, 1.0, and 1.5 m from the smoker received mean PM2.5 personal exposures of 59, 40, and 28 microg/m3, respectively, compared with a background level of 1.7 microg/m3. Like the PM2.5 concentrations, UFP concentrations measured 0.5 m from the smoker increased abruptly when a cigarette started and decreased when the cigarette ended, averaging 44,500 particles/cm3 compared with the background level of 7200 particles/cm3. During nonsmoking periods, the UFP background concentrations showed occasional peaks due to traffic, whereas PM2.5 background concentrations were extremely low. The results indicate that a single cigarette smoked outdoors at a bus stop can cause PM2.5 and UFP concentrations near the smoker that are 16-35 and 6.2 times, respectively, higher than the background concentrations due to cars and trucks on an adjacent arterial highway. Rules banning smoking indoors have been widely adopted in the United States and in

  2. Source, health risk and composition impact of outdoor very fine particles (VFPs) to school indoor environment in Xi'an, Northwestern China.

    Science.gov (United States)

    Xu, Hongmei; Guinot, Benjamin; Cao, Junji; Li, Yaqi; Niu, Xinyi; Ho, Kin Fai; Shen, Zhenxing; Liu, Suixin; Zhang, Ting; Lei, Yali; Zhang, Qian; Sun, Jian; Gao, Jinjin

    2018-01-15

    Very fine particles (VFPs, PM 0.25 ) are able to travel deeply into the respiratory tract and can produce adverse health effects, especially to children. Information on the VFPs in schools is generally lacking. We investigated the chemical compositions, sources and health risks of VFPs in a junior secondary school of Xi'an, China, during May 16th to 30th, 2012. The results showed that organic matter (37% and 39%), SO 4 2- (13% and 11%) and geological material (20% and 24%) were the major components of VFPs both outdoors and indoors. The VFP species indoors, such as SO 4 2- and elemental carbon, are mainly from outdoor origins, e.g. coal burning and traffic emissions. But particle resuspension by student activities, chalk dust and import from outdoors of soil dust also contributed to deteriorate air quality in the classroom. By contrast to outdoors, several indoor factors, like higher room temperature, limited volume and longer suspension time of classroom particles, can even lead to significant secondary pollutant production. Heavy metals (mainly from outside) bound to indoor VFPs are supposedly associated to non-cancer health risks, especially Pb through ingestion pathway and Mn through dermal contact. Outdoor VFPs may be associated to PAHs cancer health risks via inhalation way. This study confirms that both indoor and outdoor sources had contributions to indoor VFPs, and that VFPs health risk should be of higher concern in urban areas of Northwestern China. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. 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.

  4. Effects of salinity and particle concentration on sediment hydrodynamics and critical bed-shear-stress for erosion of fine grained sediments used in wetland restoration projects

    Directory of Open Access Journals (Sweden)

    M. Ghose-Hajra

    2015-03-01

    Full Text Available Sea-level rise, the increasing number and intensity of storms, oil and groundwater extraction, and coastal land subsidence are putting people and property at risk along Louisiana’s coast, with major implications for human safety and economic health of coastal areas. A major goal towards re-establishing a healthy and sustainable coastal ecosystem has been to rebuild Louisiana’s disappearing wetlands with fine grained sediments that are dredged or diverted from nearby rivers, channels and lakes to build land in open water areas. A thorough geo-hydrodynamic characterization of the deposited sediments is important in the correct design and a more realistic outcome assessment of the long-term performance measures for ongoing coastal restoration projects. This paper evaluates the effects of salinity and solid particle concentration on the re-suspension characteristics of fine-grained dredged sediments obtained from multiple geographic locations along the Gulf coast. The critical bed-shear-stress for erosion has been evaluated as a function of sedimentation time. The sediment hydrodynamic properties obtained from the laboratory testing were used in a numerical coastal sediment distribution model to aid in evaluating sediment diversions from the Mississippi River into Breton Sound and Barataria Bay.

  5. Distribution of the solvent-extractable organic compounds in fine (PM1) and coarse (PM1-10) particles in urban, industrial and forest atmospheres of Northern Algeria.

    Science.gov (United States)

    Ladji, Riad; Yassaa, Noureddine; Balducci, Catia; Cecinato, Angelo; Meklati, Brahim Youcef

    2009-12-20

    The distribution of the solvent-extractable organic components in the fine (PM(1)) and coarse (PM(1-10)) fractions of airborne particulate was studied for the first time in Algeria. That was done during October 2006 concurrently in a big industrial district, a busy urban area, and a forest national park located in Algiers, Boumerdes, Blida, respectively, which are the three biggest provinces of Northern Algeria. Most of the organic matter identified in both particle size ranges consisted of n-alkanes and n-alkanoic acids, with minor contributions coming from polycyclic aromatic hydrocarbons (PAHs), nitrated polycyclic aromatic hydrocarbons (NPAHs), oxygenated PAHs, and other polar compounds (e.g., caffeine and nicotine). The potential emission sources of airborne contaminants were reconciled by combining the values of n-alkane carbon preference index (CPI) and selected diagnostic ratios of PAHs, calculated in both size ranges. The mean cumulative concentrations of PAHs reached 3.032 ng m(-3) at the Boumerdes site, urban, 80% of which (i.e. 2.246 ng m(-3)) in the PM(1) fraction, 6.462 ng m(-3) at Rouiba-Réghaia, industrial district, (5.135 ng m(-3) or 80% in PM(1)), and 0.512 ng m(-3) at Chréa, forested mountains (0.370 ng m(-3) or 72% in PM(1)). Similar patterns were shown by all organic groups, which resulted overall enriched in the fine particles at the three sites. Carcinogenic and mutagenic potencies associated to PAHs were evaluated by multiplying the concentrations of "toxic" compounds times the corresponding potency factors normalized vs. benzo(a)pyrene (BaP), and were found to be both acceptable.

  6. Modeling the migration of fallout radionuclides to quantify the contemporary transfer of fine particles in Luvisol profiles under different land uses and farming practices

    International Nuclear Information System (INIS)

    Jagercikova, M.; Balesdent, J.; Cornu, S.; Evrard, O.; Lefevre, I.

    2014-01-01

    Soil mixing and the downward movement of solid matter in soils are dynamic pedological processes that strongly affect the vertical distribution of all soil properties across the soil profile. These processes are affected by land use and the implementation of various farming practices, but their kinetics have rarely been quantified. Our objective was to investigate the vertical transfer of matter in Luvisols at long-term experimental sites under different land uses (cropland, grassland and forest) and different farming practices (conventional tillage, reduced tillage and no tillage). To investigate these processes, the vertical radionuclide distributions of 137 Cs and 210 Pb (xs) were analyzed in 9 soil profiles. The mass balance calculations showed that as much as 91± 9% of the 137 Cs was linked to the fine particles (2 mm). To assess the kinetics of radionuclide redistribution in soil, we modeled their depth profiles using a convection-diffusion equation. The diffusion coefficient represented the rate of bioturbation, and the convection velocity provided a proxy for fine particle leaching. Both parameters were modeled as either constant or variable with depth. The tillage was simulated using an empirical formula that considered the tillage depth and a variable mixing ratio depending on the type of tillage used. A loss of isotopes due to soil erosion was introduced into the model to account for the total radionuclide inventory. All of these parameters were optimized based on the 137 Cs data and were then subsequently applied to the 210 Pb (xs) data. Our results show that the 137 Cs isotopes migrate deeper under grasslands than under forests or croplands. Additionally, our results suggest that the diffusion coefficient decreased with depth and that it remained negligible below the tillage depth at the cropland sites, below 20 cm in the forest sites, and below 80 cm in the grassland sites. (authors)

  7. In Utero Fine Particle Air Pollution and Placental Expression of Genes in the Brain-Derived Neurotrophic Factor Signaling Pathway: An ENVIRONAGE Birth Cohort Study.

    Science.gov (United States)

    Saenen, Nelly D; Plusquin, Michelle; Bijnens, Esmée; Janssen, Bram G; Gyselaers, Wilfried; Cox, Bianca; Fierens, Frans; Molenberghs, Geert; Penders, Joris; Vrijens, Karen; De Boever, Patrick; Nawrot, Tim S

    2015-08-01

    Developmental processes in the placenta and the fetal brain are shaped by the same biological signals. Recent evidence suggests that adaptive responses of the placenta to the maternal environment may influence central nervous system development. We studied the association between in utero exposure to fine particle air pollution with a diameter ≤ 2.5 μm (PM2.5) and placental expression of genes implicated in neural development. Expression of 10 target genes in the brain-derived neurotrophic factor (BDNF) signaling pathway were quantified in placental tissue of 90 mother-infant pairs from the ENVIRONAGE birth cohort using quantitative real-time polymerase chain reaction. Trimester-specific PM2.5 exposure levels were estimated for each mother's home address using a spatiotemporal model. Mixed-effects models were used to evaluate the association between the target genes and PM2.5 exposure measured in different time windows of pregnancy. A 5-μg/m3 increase in residential PM2.5 exposure during the first trimester of pregnancy was associated with a 15.9% decrease [95% confidence interval (CI): -28.7, -3.2%, p = 0.015] in expression of placental BDNF at birth. The corresponding estimate for synapsin 1 (SYN1) was a 24.3% decrease (95% CI: -42.8, -5.8%, p = 0.011). Placental expression of BDNF and SYN1, two genes implicated in normal neurodevelopmental trajectories, decreased with increasing in utero exposure to PM2.5. Future studies are needed to confirm our findings and evaluate the potential relevance of associations between PM2.5 and placental expression of BDNF and SYN1 on neurodevelopment. We provide the first molecular epidemiological evidence concerning associations between in utero fine particle air pollution exposure and the expression of genes that may influence neurodevelopmental processes.

  8. Inhalation health effects of fine particles from the co-combustion of coal and refuse derived fuel

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.; Wendt, J.O.L.; Wolski, N.; Hein, K.R.G.; Wang, S.J.; Witten, M.L. [University of Arizona, Tucson, AZ (USA). Dept. of Chemical & Environmental Engineering

    2003-06-01

    This paper is concerned with health effects from the inhalation of particulate matter (PM) emitted from the combustion of coal, and from the co-combustion of refuse derived fuel (RDF) and pulverized coal mixtures, under both normal and low NOx conditions. Specific issues focus on whether the addition of RDF to coal has an effect on PM toxicity, and whether the application of staged combustion (for low NOx) may also be a factor in this regard. Results on tests on mice show that the re-suspended coal/RDF ash appeared to cause very different effects on lung permeability than did coal ash alone. For the coal/RDF, the greatest lung damage (in terms of lung permeability increase) occurred at the short exposure period of 8 days, and thereafter appeared to be gradually repaired. Ash from staged (low NOx) combustion of coal/RDF appeared to cause greater lung injury than that from unstaged (high NOx) coal/RDF combustion, although the temporal behavior and (apparent) repair processes in each case were similar. In contrast to this, coal ash alone showed a slight decrease of lung permeability after 1 and 3 days, and this disappeared after 12 days. These observations are interpreted in the light of mechanisms proposed in the literature. The results all suggest that the composition of particles actually inhaled is important in determining lung injury. Particle size segregated leachability measurements showed that water soluble sulfur, zinc, and vanadium, but not iron, were present in the coal/RDF ash particles, which caused lung permeabilities to increase. However, the differences in health effects between unstaged and staged coal/RDF combustion could not be attributed to variations in pH values of the leachate.

  9. 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

    in particle size distribution, chemical composition and the resulting biological effects when A549 cells were incubated with the PM. These characteristics and observations in the oven hall indicated that the PM source was oven exhaust, which was well combusted. (c) 2007 Elsevier B.V. All rights reserved.......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...

  10. Use of CAH-degrading bacteria as test-organisms for evaluating the impact of fine zerovalent iron particles on the anaerobic subsurface environment.

    Science.gov (United States)

    Velimirovic, Milica; Simons, Queenie; Bastiaens, Leen

    2015-09-01

    The release of fine zerovalent iron (ZVI) particles in the environment after being introduced for in-situ treatment of compounds like chlorinated aliphatic hydrocarbons (CAHs) may raise questions toward environmental safety, especially for nanoscale materials. Classical single-species ecotoxicity tests do focus on aerobic conditions and are only relevant for the scenario when ZVI-particles reach surface water. Herein, we present an alternative approach where a CAH-degrading mixed bacterial culture was used as test-organisms relevant for the anaerobic subsurface. The impact of different ZVI particles on the bacterial culture was evaluated mainly by quantifying ATP, a reporter molecule giving a general indication of the microbial activity. These lab-scale batch tests were performed in liquid medium, without protecting and buffering aquifer material, as such representing worst-case scenario. The activity of the bacterial culture was negatively influenced by nanoscale zerovalent iron at doses as low as 0.05 g L(-1). On the other hand, concentrations up to 2 g L(-1) of several different types of microscale zerovalent iron (mZVI) particles stimulated the activity. However, very high doses of 15-30 g L(-1) of mZVI showed an inhibiting effect on the bacterial community. Negative effects of ZVIs were confirmed by H2 accumulation in the batch reactors and the absence of lactate consumption. Observed inhibition also corresponded to a pH increase above 7.5, explicable by ZVI corrosion that was found to be dose-dependent. The obtained results suggest that low doses of mZVIs will not show severe inhibition effects on the microbial community once used for in-situ treatment of CAHs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  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. Contribution of fine filler particles to energy dissipation during wet sliding of elastomer compounds on a rough surface

    International Nuclear Information System (INIS)

    Pan Xiaodong

    2007-01-01

    Elastomer compounds reinforced with precipitated silica can exhibit elevated wet sliding friction on a rough surface in comparison with corresponding compounds filled with carbon black particles. The underlying mechanism is currently not well understood. To unravel this puzzling observation, the variation of wet sliding friction with filler volume fraction is examined at the sliding speed of the order of 1 m s -1 under different lubrication conditions. Depending on the lubrication liquid-water or ethanol-a compound that shows both higher bulk hysteretic loss and lower modulus does not always exhibit a higher wet sliding friction. A thorough characterization of the bulk rheology of the compounds investigated fails to provide the rationale for such behaviour, thus constituting an apparent violation of the conventional viscoelastic understanding of rubber friction on a rough surface. On the other hand, the detected lowering of friction when the lubrication liquid is changed from water to ethanol resembles the effect of liquid medium on interfacial adhesion reported in the literature. Hence, it is suggested that a stronger interfacial attractive interaction should exist in water between the road surface and silica particles on the compound surface immediately next to the road surface. This should be related to the elevated wet sliding friction detected for silica-filled compounds under water lubrication

  13. Water Soluble Organic Nitrogen (WSON) in Ambient Fine Particles Over a Megacity in South China: Spatiotemporal Variations and Source Apportionment

    Science.gov (United States)

    Yu, Xu; Yu, Qingqing; Zhu, Ming; Tang, Mingjin; Li, Sheng; Yang, Weiqiang; Zhang, Yanli; Deng, Wei; Li, Guanghui; Yu, Yuegang; Huang, Zhonghui; Song, Wei; Ding, Xiang; Hu, Qihou; Li, Jun; Bi, Xinhui; Wang, Xinming

    2017-12-01

    Organic nitrogen aerosols are complex mixtures and important compositions in ambient fine particulate matters (PM2.5), yet their sources and spatiotemporal patterns are not well understood particularly in regions influenced by intensive human activities. In this study, filter-based ambient PM2.5 samples at four stations (one urban, two rural, plus one urban roadside) and PM samples from combustion sources (vehicle exhaust, ship emission, and biomass burning) were collected in the coastal megacity Guangzhou, south China, for determining water soluble organic nitrogen (WSON) along with other organic and inorganic species. The annual average WSON concentrations, as well as the ratios of WSON to water soluble total nitrogen, were all significantly higher at rural sites than urban sites. Average WSON concentrations at the four sites during the wet season were quite near each other, ranging from 0.41 to 0.49 μg/m3; however, they became 2 times higher at the rural sites than at the urban sites during the dry season. Five major sources for WSON were identified through positive matrix factorization analysis. Vehicle emission (29.3%), biomass burning (22.8%), and secondary formation (20.2%) were three dominant sources of WSON at the urban station, while vehicle emission (45.4%) and dust (28.6%) were two dominant sources at the urban roadside station. At the two rural sites biomass burning (51.1% and 34.1%, respectively) and secondary formation (17.8% and 30.5%, respectively) were dominant sources of WSON. Ship emission contributed 8-12% of WSON at the four sites. Natural vegetation seemed to have very minor contribution to WSON.

  14. Induction of chromosome aberrations in cultured human lymphocytes treated with sand dust storm fine particles (PM2.5).

    Science.gov (United States)

    Wei, Aili; Meng, Ziqiang

    2006-09-30

    The clastogenic activity of airborne air fine particulate matter (PM2.5, particulates with an aerodynamic diameter dust storm PM2.5 and its extract. In order to investigate the clastogenic activity of sand dust storm PM2.5 (include its organic and inorganic extract) on human lymphocytes, the normal PM2.5 and sand dust storm PM2.5 samples were collected in Wuwei city (Gansu Province) and Baotou city (Inner Mongolia), China. The chromosomal aberration (CA) test was employed and the cells were treated with 0, 33, 100, 300 microg ml(-1) sand dust storm or normal ambient air PM2.5 suspension (physiological saline as solvent control), or inorganic extract (0, 75, 150, 300 microg ml(-1), physiological saline as solvent control) or organic extract (0, 20, 40, 80 microg ml(-1), DMSO as solvent control) at the beginning of the cell culture. The results indicated that sand dust storm PM2.5 and its extract as well as normal samples can induce increase in CA frequency. With the increase of treatment concentrations the CA frequency increased and the mitotic index (MI) values declined in a dose-response manner. In the same concentrates, the CA frequency of normal ambient air PM2.5 and its extract were significant higher than those of sand dust storm PM2.5 (P0.05). The toxicity of sand dust storm PM2.5 and its extract at high dose is very potent. CA frequency of normal PM2.5 (include its organic extract) from Baotou were higher than those of Wuwei especially in low and middle dose (Pdust storm PM2.5 (include its all extract) was not significant different between the cities (P>0.05).

  15. 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

    2013-06-01

    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 eastern China. Ozone and PM2.5 showed strong 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 a 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 mid-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions.

  16. Prenatal exposure to fine particles and polycyclic aromatic hydrocarbons and birth outcomes: a two-pollutant approach.

    Science.gov (United States)

    Jedrychowski, W A; Majewska, Renata; Spengler, J D; Camann, David; Roen, E L; Perera, F P

    2017-04-01

    Previous epidemiologic studies have considered the effects of individual air pollutants on birth outcomes, whereas a multiple-pollutant approach is more relevant to public health policy. The present study compared the observed effect sizes of prenatal fine particulate matter (PM 2.5 ) and polycyclic aromatic hydrocarbons (PAH) (a component of PM 2.5 ) exposures on birth outcome deficits, assessed by the single vs. two-pollutant approaches. The study sample included 455 term infants born in Krakow to non-smoking mothers, among whom personal exposures to PM 2.5 and PAH were monitored in the second trimester of pregnancy. The exposure effect estimates (unstandardized and standardized regression coefficients) on birth outcomes were determined using multivariable linear regression models, accounting for relevant covariates. In the single-pollutant approach, each pollutant was inversely associated with all birth outcomes. The effect size of prenatal PAH exposure on birth weight and length was twice that of PM 2.5, in terms of standardized coefficients. In the two-pollutant approach, the negative effect of PM 2.5 on birth weight and length, adjusted for PAH exposure, lost its significance. The standardized effect of PAH on birth weight was 10-fold stronger (β = -0.20, p = 0.004) than that estimated for PM 2.5 (β = -0.02, p = 0.757). The results provide evidence that PAH had a greater impact on several measures of fetal development, especially birth weight, than PM 2.5 . Though in the single-pollutant models PM 2.5 had a significant impact on birth outcomes, this effect appears to be mediated by PAH.

  17. Exhaust Fine Particle and Nitrogen Oxide Emissions from Individual Heavy-Duty Trucks at the Port of Oakland

    Science.gov (United States)

    Dallmann, T. R.; Harley, R. A.; Kirchstetter, T.

    2010-12-01

    Heavy-duty (HD) diesel trucks are a source of nitrogen oxide (NOx) emissions as well as primary fine particulate matter (PM2.5) that includes black carbon (BC) as a major component. Heavy-duty trucks contribute significantly to elevated levels of diesel particulate matter found near highways and in communities surrounding major freight-handling facilities. To reduce the air quality impact of diesel engine emissions, the California Air Resources Board has adopted new rules requiring the retrofit or replacement of in-use HD trucks. These rules take effect during 2010 at ports and railyards, and apply to all trucks operating in California by 2014. This study involves on-road measurements of PM2.5, BC, and NOx emission factor distributions from individual HD trucks driving into the Port of Oakland in the San Francisco Bay area. Measurements of exhaust plumes from individual trucks were made using a mobile laboratory equipped with fast time response (1 Hz) PM2.5, BC, NOx, and carbon dioxide (CO2) sensors. The mobile laboratory was stationed on an overpass above an arterial roadway that connects the Port to a nearby highway (I-880). The air sampling inlet was thereby located above the vertical exhaust pipes of HD diesel trucks passing by on the arterial roadway below. Fuel-specific PM2.5, BC, and NOx emission factors for individual trucks were calculated using a carbon balance method in which concentrations of these species in an exhaust plume are normalized to CO2 concentrations. Initial field sampling was conducted in November, 2009 prior to the implementation of new emission rules. Additional emission measurements were made at the same location during June 2010 and emission factor distributions and averages will be compared.

  18. Surface Improvement Technology “Wonder Process Craft (WPC)” by Rapid Impact of Fine Particle

    Science.gov (United States)

    Miyasaka, Yoshio

    Based on our sandblast and shot peening technology, we have found that utilizing relatively smaller powder for sandblasting enables the modification or the organizational and mechanical features of the ingredient's surface, defying the conventional thought in this subject manner. The technology mentioned previously can be utilized on various ingredients and machinery parts, and its effect is widely recognized. By blasting titanium particles onto the surface of metals, ceramics, or combined substances utilizing the previously mentioned technology, it is possible to attain a thin film layer of titanium deposit that is effective in catalyzing light. This is PIP (Powder Impact Plating) natural catalyst. In today's world where environmental destruction has become a serious issue, we hope to contribute to the improvement of the environment with our highly efficient catalyst.

  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. Seasonal variations of ultra-fine and submicron aerosols in Taipei, Taiwan: implications for particle formation processes in a subtropical urban area

    Directory of Open Access Journals (Sweden)

    H. C. Cheung

    2016-02-01

    Full Text Available 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

  1. Evaluation of micronucleus induction of sand dust storm fine particles (PM(2.5)) in human blood lymphocytes.

    Science.gov (United States)

    Wei, Aili; Meng, Ziqiang

    2006-11-01

    Sand dust storms are common phenomena in the arid and semi-arid regions. Previous studies have demonstrated that the airborne air fine particulate matter (PM(2.5), particulates with an aerodynamic diameter ≤2.5μm) and its extracts can induce human genetic damage of lymphocytes such as micronucleus formation, chromosomal aberration and so on. However, little is known about the health risks associated with sand dust storm PM(2.5) and its extracts. The aim of the present study is to investigate the micronucleus induction of sand dust storm PM(2.5) (include its organic and inorganic extract) from two different towns on human lymphocytes. The samples of normal PM(2.5) and sand dust storm PM(2.5) were collected in Wuwei (Gansu Province) and Baotou (Inner Mongolia), China. The cytochalasin-B cytokinesis-block test was employed and the cells were treated with 0, 33, 100, 300μgml(-1) sand dust storm PM(2.5) or normal ambient air PM(2.5) suspension (physiological saline as solvent control), or inorganic extract (0, 75, 150, 300μgml(-1), physiological saline as solvent control) or organic extract (0, 20, 40, 80μgml(-1), DMSO as solvent control) at the beginning of the cell culture. Both sand dust storm and normal PM(2.5) and their extract treatment cultures revealed an increase in the frequency of micronucleus. With the increase of treatment concentrations the frequency of micronucleus increased and the nuclear division index (NDI) values declined in a dose-response manner (Pdust storm PM(2.5) (P0.05). The toxicity of sand dust storm PM(2.5) and its extract at high dose is very potent. The frequency of micronucleus of normal PM(2.5) (include its organic extract) from Baotou were higher than those of Wuwei especially in low and middle dose (Pdust storm PM(2.5) (include its all extract) was not significantly different between the towns (P>0.05).

  2. Early wheezing phenotypes and severity of respiratory illness in very early childhood: study on intrauterine exposure to fine particle matter.

    Science.gov (United States)

    Jedrychowski, Wieslaw; Perera, Frederica P; Maugeri, Umberto; Mrozek-Budzyn, Dorota; Mroz, Elzbieta; Flak, Elzbieta; Edwards, Susan; Spengler, John D; Jacek, Ryszard; Sowa, Agata; Musiał, Agnieszka

    2009-08-01

    The main goal of the paper was to assess the pattern of risk factors having an impact on the onset of early wheezing phenotypes in the birth cohort of 468 two-year olds and to investigate the severity of respiratory illness in the two-year olds in relation to both wheezing phenotypes, environmental tobacco smoke (ETS) and personal PM(2.5) exposure over pregnancy period (fine particulate matter). The secondary goal of the paper was to assess possible association of early persistent wheezing with the length of the baby at birth. Pregnant women were recruited from ambulatory prenatal clinics in the first and second trimester of pregnancy. Only women 18-35 years of age, who claimed to be non-smokers, with singleton pregnancies, without illicit drug use and HIV infection, free from chronic diseases were eligible for the study. In the statistical analysis of respiratory health of children multinomial logistic regression and zero-inflated Poisson regression models were used. Approximately one third of the children in the study sample experienced wheezing in the first 2 years of life and in about two third of cases (67%) the symptom developed already in the first year of life. The early wheezing was easily reversible and in about 70% of infants with wheezing the symptom receded in the second year of life. The adjusted relative risk ratio (RRR) of persistent wheezing increased with maternal atopy (RRR=3.05; 95%CI: 1.30-7.15), older siblings (RRR=3.05; 95%CI: 1.67-5.58) and prenatal ETS exposure (RRR=1.13; 95%CI: 1.04-1.23), but was inversely associated with the length of baby at birth (RRR=0.88; 95%CI: 0.76-1.01). The adjusted incidence risk ratios (IRR) of coughing, difficult breathing, runny/stuffy nose and pharyngitis/tonsillitis in wheezers were much higher than that observed among non-wheezers and significantly depended on prenatal PM(2.5) exposure, older siblings and maternal atopy. The study shows a clear inverse association between maternal age or maternal education

  3. EARLY WHEEZING PHENOTYPES AND SEVERITY OF RESPIRATORY ILLNESS IN VERY EARLY CHILDHOOD. STUDY ON INTRAUTERINE EXPOSURE TO FINE PARTICLE MATTER

    Science.gov (United States)

    Jedrychowski, Wieslaw; Perera, Frederica P.; Maugeri, Umberto; Mrozek-Budzyn, Dorota; Mroz, Elzbieta; Flak, Elzbieta; Edwards, Susan; Spengler, John D.; Jacek, Ryszard; Sowa, Agata; Musia, Agnieszka

    2009-01-01

    The main goal of the paper was to assess the pattern of risk factors having an impact on the onset of early wheezing phenotypes in the birth cohort of 468 two-year olds and to investigate the severity of respiratory illness in the two-year olds in relation to both wheezing phenotypes, environmental tobacco smoke (ETS) and personal PM2.5 exposure over pregnancy period (fine particulate matter). The secondary goal of the paper was to assess possible association of early persistent wheezing with the length of the baby at birth. Pregnant women were recruited from ambulatory prenatal clinics in the first and second trimester of pregnancy. Only women 18–35 years of age, who claimed to be non-smokers, with singleton pregnancies, without illicit drug use and HIV infection, free from chronic diseases were eligible for the study. In the statistical analysis of respiratory health of children multinomial logistic regression and zero-inflated Poisson regression models were used. Approximately one third of the children in the study sample experienced wheezing in the first two years of life and in about two third of cases (67%) the symptom developed already in the first year of life. The early wheezing was easily reversible and in about 70% of infants with wheezing the symptom receded in the second year of life. The adjusted relative risk ratio (RRR) of persistent wheezing increased with maternal atopy (RRR = 3.05; 95%CI: 1.30 – 7.15), older siblings (RRR = 3.05; 95%CI: 1.67 – 5.58) and prenatal ETS exposure (RRR= 1.13; 95%CI: 1.04 – 1.23), but was inversely associated with the length of baby at birth (RRR = 0.88; 95%CI: 0.76 – 1.01). The adjusted incidence risk ratios (IRR) of coughing, difficult breathing, runny/stuffy nose and pharyngitis/tonsillitis in wheezers were much higher than that observed among non-wheezers and significantly depended on prenatal PM2.5 exposure, older siblings and maternal atopy. The study shows a clear inverse association between maternal

  4. 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

  5. Relative Precision of Inhaler Aerodynamic Particle Size Distribution (APSD) Metrics by Full Resolution and Abbreviated Andersen Cascade Impactors (ACIs): Part 2—Investigation of Bias in Extra-Fine Mass Fraction with AIM-HRT Impactor

    OpenAIRE

    Mitchell, Jolyon P.; Nagel, Mark W.; Doyle, Cathy C.; Ali, Rubina S.; Avvakoumova, Valentina I.; Christopher, J. David; Quiroz, Jorge; Strickland, Helen; Tougas, Terrence; Lyapustina, Svetlana

    2010-01-01

    The purpose of this study was to resolve an anomalously high measure of extra-fine particle fraction (EPF) determined by the abbreviated cascade impactor possibly relevant for human respiratory tract (AIM-HRT) in the experiment described in Part 1 of this two-part series, in which the relative precision of abbreviated impactors was evaluated in comparison with a full resolution Andersen eight-stage cascade impactor (ACI). Evidence that the surface coating used to mitigate particle bounce was ...

  6. Fine and ultrafine particles of the diet: influence on the mucosal immune response and association with Crohn's disease.

    Science.gov (United States)

    Lomer, Miranda C E; Thompson, Richard P H; Powell, Jonathan J

    2002-02-01

    Crohn's disease is a modern Western disease characterised by transmural inflammation of the gastrointestinal tract. It is of unknown aetiology, but evidence suggests that it results from a combination of genetic predisposition and environmental factors. Bacterial-sized microparticles (0.1-1.0 microm) are potent adjuvants in model antigen-mediated immune responses and are increasingly associated with disease. Microparticles of TiO2 and aluminosilicate accumulate in macrophages of human gut-associated lymphoid tissue where the earliest signs of lesions in Crohn's disease are observed. Dietary microparticles are of endogenous or exogenous origin. Endogenous microparticles dominate and are calcium phosphate (most probably hydroxyapatite), which precipitates in the lumen of the mid-distal gastrointestinal tract due to secretion of Ca and phosphate in the succus entericus. Exogenous dietary microparticles are contaminants (soil and/or dust) and food additives. TiO2, for example, is a food colourant, and aluminosilicates are anti-caking agents, although some aluminosilicates occur as natural contaminants. Food additives alone account for ingestion of approximately 10(12) particles/person per d. Possible mechanisms for the role of exogenous and endogenous dietary microparticles in promoting toleragenic or immune responses of gastrointestinal mucosal phagocytosis are discussed. In a double-blind randomised pilot study we have shown that a diet low in Ca and exogenous microparticles appears to alleviate the symptoms of ileal Crohn's disease, with a significant (P= 0.002) improvement in the Crohn's disease activity index. A multi-centre trial and further mechanistic studies at the cellular level are underway.

  7. Plastic casting resin poisoning

    Science.gov (United States)

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  8. Apparatus and method for removing solvent from carbon dioxide in resin recycling system

    Science.gov (United States)

    Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

    2009-01-06

    A two-step resin recycling system and method solvent that produces essentially contaminant-free synthetic resin material. The system and method includes one or more solvent wash vessels to expose resin particles to a solvent, the solvent contacting the resin particles in the one or more solvent wash vessels to substantially remove contaminants on the resin particles. A separator is provided to separate the solvent from the resin particles after removal from the one or more solvent wash vessels. The resin particles are next exposed to carbon dioxide in a closed loop carbon dioxide system. The closed loop system includes a carbon dioxide vessel where the carbon dioxide is exposed to the resin, substantially removing any residual solvent remaining on the resin particles after separation. A separation vessel is also provided to separate the solvent from the solvent laden carbon dioxide. Both the carbon dioxide and the solvent are reused after separation in the separation vessel.

  9. Resin composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne; Lussi, Adrian

    2014-01-01

    OBJECTIVE: To investigate how the modulus of elasticity of resin composites influences marginal quality in restorations submitted to thermocyclic and mechanical loading. METHODS: Charisma, Filtek Supreme XTE and Grandio were selected as they were found to possess different moduli of elasticity...... of resin composite (p=0.81) on the quality of dentine margins was observed, before or after loading. Deterioration of all margins was evident after loading (p....008). CONCLUSIONS: The resin composite with the highest modulus of elasticity resulted in the highest number of gap-free enamel margins but with an increased incidence of paramarginal enamel fractures. CLINICAL SIGNIFICANCE: The results from this study suggest that the marginal quality of restorations can...

  10. Field characterization of the PM2.5 Aerosol Chemical Speciation Monitor: insights into the composition, sources, and processes of fine particles in eastern China

    Science.gov (United States)

    Zhang, Yunjiang; Tang, Lili; Croteau, Philip L.; Favez, Olivier; Sun, Yele; Canagaratna, Manjula R.; Wang, Zhuang; Couvidat, Florian; Albinet, Alexandre; Zhang, Hongliang; Sciare, Jean; Prévôt, André S. H.; Jayne, John T.; Worsnop, Douglas R.

    2017-12-01

    A PM2.5-capable aerosol chemical speciation monitor (Q-ACSM) was deployed in urban Nanjing, China, for the first time to measure in situ non-refractory fine particle (NR-PM2.5) composition from 20 October to 19 November 2015, along with parallel measurements of submicron aerosol (PM1) species by a standard Q-ACSM. Our results show that the NR-PM2.5 species (organics, sulfate, nitrate, and ammonium) measured by the PM2.5-Q-ACSM are highly correlated (r2 > 0.9) with those measured by a Sunset Lab OC  /  EC analyzer and a Monitor for AeRosols and GAses (MARGA). The comparisons between the two Q-ACSMs illustrated similar temporal variations in all NR species between PM1 and PM2.5, yet substantial mass fractions of aerosol species were observed in the size range of 1-2.5 µm. On average, NR-PM1-2.5 contributed 53 % of the total NR-PM2.5, with sulfate and secondary organic aerosols (SOAs) being the two largest contributors (26 and 27 %, respectively). Positive matrix factorization of organic aerosol showed similar temporal variations in both primary and secondary OAs between PM1 and PM2.5, although the mass spectra were slightly different due to more thermal decomposition on the capture vaporizer of the PM2.5-Q-ACSM. We observed an enhancement of SOA under high relative humidity conditions, which is associated with simultaneous increases in aerosol pH, gas-phase species (NO2, SO2, and NH3) concentrations and aerosol water content driven by secondary inorganic aerosols. These results likely indicate an enhanced reactive uptake of SOA precursors upon aqueous particles. Therefore, reducing anthropogenic NOx, SO2, and NH3 emissions might not only reduce secondary inorganic aerosols but also the SOA burden during haze episodes in China.

  11. 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

    International Nuclear Information System (INIS)

    Schreck, Eva; Laplanche, Christophe; Le Guédard, Marina; Bessoule, Jean-Jacques; Austruy, Annabelle; Xiong, Tiantian; Foucault, Yann; Dumat, Camille

    2013-01-01

    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. -- Highlights: •The study compares foliar and root transfers of metal(loid)s and their effects on plants. •Field experiments are performed combining ecotoxicological and statistical analyses. •The use of leaf fatty acid composition is a relevant indicator of exposure pathway. •The uptake pathways are independent, with an additive effect in terms of phytotoxicity. -- Metal uptake via both foliar and root pathways alters in a distinctive manner the fatty acid composition of lettuce leaves

  12. 2,4-Dichlorophenol Enzymatic Removal and Its Kinetic Study Using Horseradish Peroxidase Crosslinked to Nano Spray-Dried Poly(Lactic-Co-Glycolic Acid) Fine Particles.

    Science.gov (United States)

    Dahili, Laura Amina; Nagy, Endre; Feczkó, Tivadar

    2017-04-28

    Horseradish peroxidase (HRP) catalyzes the oxidation of aromatic compounds by hydrogen peroxide via insoluble polymer formation, which can be precipitated from the wastewater. For HRP immobilization, poly(lactic-co-glycolic acid) (PLGA) fine carrier supports were produced by using the Nano Spray Dryer B-90. Immobilized HRP was used to remove the persistent 2,4-dichlorophenol from model wastewater. Both extracted (9-16 U/g) and purified HRP (11-25 U/g) retained their activity to a high extent after crosslinking to the PLGA particles. The immobilized enzyme activity was substantially higher in both the acidic and the alkaline pH regions compared with the free enzyme. Optimally, 98% of the 2,4-dichlorophenol could be eliminated using immobilized HRP due to catalytic removal and partly to adsorption on the carrier supports. Immobilized enzyme kinetics for 2,4-dichlorophenol elimination was studied for the first time, and it could be concluded that competitive product inhibition took place.

  13. Produced water treatment using polymeric resins; Resinas polimericas para tratamento da agua produzida

    Energy Technology Data Exchange (ETDEWEB)

    Louvisse, Ana Maria Travalloni; Freire, Norma de Oliveira [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; Queiros, Yure Gomes de Carvalho; Silva, Carla Michele Frota da; Barros, Cintia Chagas; Lucas, Elizabeth Fernandes [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas

    2008-07-01

    The treatment and disposal of oily waters from oil production and refining processes represent an important technological pass for attendance of the ambient legislation and to the politics of the Cia of search of the environmental excellence. The reuse or reinjection of the co-produced water has been considered an interesting strategical alternative, however, the water quality requirement for these processes demands a pretreatment step, considering the exit effluent from primary and secondary treatment processes currently used. This work presents resulted of the polymeric resin development for tertiary treatment of oily waters with low oil and grasses content and fine solids, including the dissolved fraction. These resins can adsorb, in reversible form, organic components. Its high adsorption capacity is determined by the polarity, superficial area, range of porosity and a wide distribution of particle size and pore. Another important characteristic is the possibility of its use in some cycles of work due to its weak forces of interaction between the contaminants and the surface of the resin. Regeneration can be carried through of diverse forms, including the use of solvent, with or without the variation of temperature and/or pH. The gotten results indicated a high resin adsorption capacity, with concentrated oily water treatment volume 10,000 times the volume of resin used. (author)

  14. Land use regression modeling of oxidative potential of fine particles, NO2, PM2.5 mass and association to type two diabetes mellitus

    Science.gov (United States)

    Hellack, Bryan; Sugiri, Dorothea; Schins, Roel P. F.; Schikowski, Tamara; Krämer, Ursula; Kuhlbusch, Thomas A. J.; Hoffmann, Barbara

    2017-12-01

    While land use regression models (LUR) are commonly used, e.g. for the prediction of spatially variable air pollutant mass concentrations, they are scarcely used for predicting the oxidative potential (OP), a suggested unifying predictor of health effects. Therefore a LUR model was developed to examine if long-term OP of fine particulate exposure can be reasonably predicted by LUR modeling and whether it is related to health effects in a study region comprised of urban and rural areas. Four 14-day sampling periods over 1 year at 40 sites in the western Ruhr Area and adjacent northern rural area, Germany, in 2002/2003 were conducted and annual Nitrogen Dioxide (NO2), fine particles (PM2.5), and OP were calculated. LUR models were developed to estimate spatially-resolved annual OP, NO2 and PM2.5 concentrations. The model performance was checked by leave-one-out cross validation (LOOCV) and cox regression was used to analyze the association of modeled residential OP and NO2 with incident type 2 diabetes mellitus (T2DM) in 1784 elderly women during a mean follow-up of 16 years (baseline 1985-1994). The measured OP and NO2 concentrations were moderately correlated (rSpearman 0.57). The LUR models explained 62% and 92% of the OP and NO2 variance (adjusted LOOCV R2 57% and 90%). PM10 emission from combustion in a 5000 m buffer was the most important predictor for OP and NO2. Modeled pollutants were highly correlated (rSpearman 0.87). Model quality for OP was sensitive to the inclusion of a single influential measurement site. For PM2.5 mass only an insufficient model with a low explained variance of 22% (adjusted R2) was developed so no health effects analyses were conducted with estimated PM2.5. Increases in OP and NO2 were associated with an increase in risk of T2DM by a hazard ratio of 1.38 (95% CI 1.06-1.80) and 1.39 (95% CI 1.07-1.81) per interquartile range of OP and NO2, respectively. We conclude that spatially-resolved OP can be predicted by LUR modeling, but

  15. Differences in allergic inflammatory responses between urban PM2.5 and fine particle derived from desert-dust in murine lungs.

    Science.gov (United States)

    He, Miao; Ichinose, Takamichi; Kobayashi, Makoto; Arashidani, Keiichi; Yoshida, Seiichi; Nishikawa, Masataka; Takano, Hirohisa; Sun, Guifan; Shibamoto, Takayuki

    2016-04-15

    The biological and chemical natures of materials adsorbed onto fine particulate matter (PM2.5) vary by origin and passage routes. The exacerbating effects of the two samples-urban PM2.5 (U-PM2.5) collected during the hazy weather in a Chinese city and fine particles (ASD-PM2.5) collected during Asian sand dust (ASD) storm event days in Japan-on murine lung eosinophilia were compared to clarify the role of toxic materials in PM2.5. The amounts of β-glucan and mineral components were higher in ASD-PM2.5 than in U-PM2.5. On the other hand, organic chemicals, including polycyclic aromatic hydrocarbons (PAHs), were higher in U-PM2.5 than in ASD-PM2.5. When BALB/c mice were intratracheally instilled with U-PM2.5 and ASD-PM2.5 (total 0.4 mg/mouse) with or without ovalbumin (OVA), various biological effects were observed, including enhancement of eosinophil recruitment induced by OVA in the submucosa of the airway, goblet cell proliferation in the bronchial epithelium, synergic increase of OVA-induced eosinophil-relevant cytokines and a chemokine in bronchoalveolar lavage fluid, and increase of serum OVA-specific IgG1 and IgE. Data demonstrate that U-PM2.5 and ASD-PM2.5 induced allergic inflammatory changes and caused lung pathology. U-PM2.5 and ASD-PM2.5 increased F4/80(+) CD11b(+) cells, indicating that an influx of inflammatory and exudative macrophages in lung tissue had occurred. The ratio of CD206 positive F4/80(+) CD11b(+) cells (M2 macrophages) in lung tissue was higher in the OVA+ASD-PM2.5 treated mice than in the OVA+U-PM2.5 treated mice. These results suggest that the lung eosinophilia exacerbated by both PM2.5 is due to activation of a Th2-associated immune response along with induced M2 macrophages and the exacerbating effect is greater in microbial element (β-glucan)-rich ASD-PM2.5 than in organic chemical-rich U-PM2.5. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Prediction of the viscosity reduction due to dissolved CO2 of and an elementary approach in the supercritical CO2 assisted continuous particle production of a polyester resin

    NARCIS (Netherlands)

    Nalawade, Sameer P.; Nieborg, Vincent H. J.; Picchioni, Francesco; Janssen, L. P. B. M.

    2006-01-01

    The dissolution of CO2 in a polymer causes plasticization of the polymer and hence, its viscosity is reduced. A model based on the free volume theory has been used for a polyester resin, which shows a considerable reduction in the viscosity due to dissolved M. Therefore, superctitical CO2 has been

  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. Tribochemical Glass Ceramic Coating as a New Approach for Resin Adhesion to Zirconia.

    Science.gov (United States)

    Wandscher, Vinícius Felipe; Fraga, Sara; Pozzobon, João Luiz; Soares, Fabio Zovico Maxnuck; Foletto, Edson Luiz; May, Liliana Gressler; Valandro, Luiz Felipe

    To investigate the effects of a novel tribochemical silica coating technique with powders made from feldspathic ceramic and leucite-based ceramic on the bond strength of zirconia to resin cement before and after aging. Zirconia blocks were divided into 3 groups according to the material used for airborne-particle abrasion: 1) SP (control): silica-coated alumina particles; 2) FP: feldspathic ceramic powder; 3) LP: leucite glass-ceramic powder. After silanization, composite resin cylinders were cemented on the zirconia surface using a dual-curing resin cement. Prior to the shear bond strength (SBS) test, half of the samples (n = 15) were stored in distilled water for 24 h; the other half (n = 15) were submitted to aging (10,000 thermocycles of 5°C to 55°C; 150 days of water storage). The bond strength data were analyzed using two-way ANOVA and Tukey's test (α = 0.05). Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction analysis were performed. The initial bond strengths did not differ significantly between the groups (p = 0.053). However, after aging procedures, airborne-particle abrasion with feldspathic ceramic powder (FP) resulted in higher values of bond strength (p = 0.0001). SEM and EDS indicated that all the treatments promoted silica deposition on the Y-TZP surface ceramic. Airborne-particle abrasion with FP and LP induced a lower percentage of the monoclinic phase. Airborne abrasion with fine feldspathic ceramic particles is a novel tribochemical technique and appears to be suitable for improving the bond strength between zirconia and resin cements.

  19. Karakteristik Komposit Resin Berkemampuan Mengalir

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The use of resin composites as posterior restoratives has markedly increased over the past decade. The patients demand for better esthetics, concerns related to possible mercury toxicity from amalgam and improvements in resin composite materials have significantly contributed the popularity of these materials. Early problems related to composites included excessive wear, less of anatomic form, post operative sensitivity, secondary caries and marginal leakage. Marginal adaptation still remains an unavoidable problem for composite restoration, especially at the gingival wall of cervical or Class II restoration. In an attempt to improve marginal sealing, many techniques and lining materials have been designed. To reduce stress generated by polymerization shrinkage, applying and curing of resin composites in layers is often recommended. Using a thick adhesive layer or low-viscosity resin may, due to its elastic properties, serve as a flexible intermediate layer and compensate for the polymerization stress created in resin composite. Flowable composites were created by retaining the same small particle size of traditional hybrid composite but reducing the filler content and allowing the increased resin to reduce the viscosity of the mixture. Flowable composites were introduced in 1996 as liners, fissure sealants and also in tunnel preparations. They have been suggested for Class I, II, III and V cavity restorations, preventive resin restorations and composite, porcelain and amalgam repairing. Their usage as a liner under high filled resins in posterior restorations has been shown to improve the adaptation of composites and effectively achieve clinically acceptable results. This article attempts to give a broad characteristics of different types of flowable composites. 

  20. Evaluating the effect of in-process material on the binding mechanisms of surrogate viral particles to a multi-modal anion exchange resin.

    Science.gov (United States)

    Brown, Matthew R; Burnham, Michael S; Johnson, Sarah A; Lute, Scott C; Brorson, Kurt A; Roush, David J

    2018-02-10

    Bacteriophage binding mechanisms to multi-modal anion exchange resin may include both anion exchange and hydrophobic interactions, or the mechanism can be dominated by a single moiety. However, previous studies have reported binding mechanisms defined for simple solutions containing only buffer and a surrogate viral spike (i.e. bacteriophage ΦX174, PR772, and PP7). We employed phage spiked in-process monoclonal antibody (mAb) pools to model binding under bioprocessing conditions. These experiments allow the individual contributions of the mAb, in-process impurities, and buffer composition on mechanistic removal of phages to be studied. PP7 and PR772 use synergetic binding by the positively charged quaternary amine and the hydrophobic aromatic phenyl group to bind multi-modal resin. ΦX174's binding mechanism remains inconclusive due to operating conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Synthesis of Prebiotic Caramels Catalyzed by Ion-Exchange Resin Particles: Kinetic Model for the Formation of Di-d-fructose Dianhydrides.

    Science.gov (United States)

    Ortiz Cerda, Imelda-Elizabeth; Thammavong, Phahath; Caqueret, Vincent; Porte, Catherine; Mabille, Isabelle; Garcia Fernandez, José Manuel; Moscosa Santillan, Mario; Havet, Jean-Louis

    2018-02-21

    Caramel enriched in di-d-fructose dianhydrides (DFAs, a family of prebiotic cyclic fructodisaccharides) is a functional food with beneficial properties for health. The aim of this work was to study the conversion of fructose into DFAs catalyzed by acid ion-exchange resin, in order to establish a simplified mechanism of the caramelization reaction and a kinetic model for DFA formation. Batch reactor experiments were carried out in a 250 mL spherical glass flask and afforded up to 50% DFA yields. The mechanism proposed entails order 2 reactions that describe fructose conversion on DFAs or formation of byproducts such as HMF or melanoidines. A third order 1 reaction defines DFA transformation into fructosyl-DFAs or fructo-oligosaccharides. The influence of fructose concentration, resin loading and temperature was studied to calculate the kinetic parameters necessary to scale up the process.

  2. Process for preparing fine grain silicon carbide powder

    Science.gov (United States)

    Wei, G.C.

    Method of producing fine-grain silicon carbide powder comprises combining methyltrimethoxysilane with a solution of phenolic resin, acetone and water or sugar and water, gelling the resulting mixture, and then drying and heating the obtained gel.

  3. Differences in allergic inflammatory responses between urban PM2.5 and fine particle derived from desert-dust in murine lungs

    International Nuclear Information System (INIS)

    He, Miao; Ichinose, Takamichi; Kobayashi, Makoto; Arashidani, Keiichi; Yoshida, Seiichi; Nishikawa, Masataka; Takano, Hirohisa; Sun, Guifan; Shibamoto, Takayuki

    2016-01-01

    The biological and chemical natures of materials adsorbed onto fine particulate matter (PM2.5) vary by origin and passage routes. The exacerbating effects of the two samples—urban PM2.5 (U-PM2.5) collected during the hazy weather in a Chinese city and fine particles (ASD-PM2.5) collected during Asian sand dust (ASD) storm event days in Japan—on murine lung eosinophilia were compared to clarify the role of toxic materials in PM2.5. The amounts of β-glucan and mineral components were higher in ASD-PM2.5 than in U-PM2.5. On the other hand, organic chemicals, including polycyclic aromatic hydrocarbons (PAHs), were higher in U-PM2.5 than in ASD-PM2.5. When BALB/c mice were intratracheally instilled with U-PM2.5 and ASD-PM2.5 (total 0.4 mg/mouse) with or without ovalbumin (OVA), various biological effects were observed, including enhancement of eosinophil recruitment induced by OVA in the submucosa of the airway, goblet cell proliferation in the bronchial epithelium, synergic increase of OVA-induced eosinophil-relevant cytokines and a chemokine in bronchoalveolar lavage fluid, and increase of serum OVA-specific IgG1 and IgE. Data demonstrate that U-PM2.5 and ASD-PM2.5 induced allergic inflammatory changes and caused lung pathology. U-PM2.5 and ASD-PM2.5 increased F4/80 + CD11b + cells, indicating that an influx of inflammatory and exudative macrophages in lung tissue had occurred. The ratio of CD206 positive F4/80 + CD11b + cells (M2 macrophages) in lung tissue was higher in the OVA + ASD-PM2.5 treated mice than in the OVA + U-PM2.5 treated mice. These results suggest that the lung eosinophilia exacerbated by both PM2.5 is due to activation of a Th2-associated immune response along with induced M2 macrophages and the exacerbating effect is greater in microbial element (β-glucan)-rich ASD-PM2.5 than in organic chemical-rich U-PM2.5. - Highlights: • The aggravating effects of urban-PM2.5 and desert-PM2.5 on lung eosinophilia were compared. • Both PM2.5 enhanced

  4. Chromatography resin support

    Science.gov (United States)

    Dobos, James G.

    2002-01-01

    An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

  5. Review: Resin Composite Filling

    OpenAIRE

    Desmond Ng; Jimmy C. M. Hsiao; Keith C. T. Tong; Harry Kim; Yanjie Mai; Keith H. S. Chan

    2010-01-01

    The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinical procedures involved and finishing and polishing techniques for resin restoration. Although resin ...

  6. A modeling study of the nonlinear response of fine particles to air pollutant emissions in the Beijing-Tianjin-Hebei region

    Science.gov (United States)

    Zhao, Bin; Wu, Wenjing; Wang, Shuxiao; Xing, Jia; Chang, Xing; Liou, Kuo-Nan; Jiang, Jonathan H.; Gu, Yu; Jang, Carey; Fu, Joshua S.; Zhu, Yun; Wang, Jiandong; Lin, Yan; Hao, Jiming

    2017-10-01

    The Beijing-Tianjin-Hebei (BTH) region has been suffering from the most severe fine-particle (PM2. 5) pollution in China, which causes serious health damage and economic loss. Quantifying the source contributions to PM2. 5 concentrations has been a challenging task because of the complicated nonlinear relationships between PM2. 5 concentrations and emissions of multiple pollutants from multiple spatial regions and economic sectors. In this study, we use the extended response surface modeling (ERSM) technique to investigate the nonlinear response of PM2. 5 concentrations to emissions of multiple pollutants from different regions and sectors over the BTH region, based on over 1000 simulations by a chemical transport model (CTM). The ERSM-predicted PM2. 5 concentrations agree well with independent CTM simulations, with correlation coefficients larger than 0.99 and mean normalized errors less than 1 %. Using the ERSM technique, we find that, among all air pollutants, primary inorganic PM2. 5 makes the largest contribution (24-36 %) to PM2. 5 concentrations. The contribution of primary inorganic PM2. 5 emissions is especially high in heavily polluted winter and is dominated by the industry as well as residential and commercial sectors, which should be prioritized in PM2. 5 control strategies. The total contributions of all precursors (nitrogen oxides, NOx; sulfur dioxides, SO2; ammonia, NH3; non-methane volatile organic compounds, NMVOCs; intermediate-volatility organic compounds, IVOCs; primary organic aerosol, POA) to PM2. 5 concentrations range between 31 and 48 %. Among these precursors, PM2. 5 concentrations are primarily sensitive to the emissions of NH3, NMVOC + IVOC, and POA. The sensitivities increase substantially for NH3 and NOx and decrease slightly for POA and NMVOC + IVOC with the increase in the emission reduction ratio, which illustrates the nonlinear relationships between precursor emissions and PM2. 5 concentrations. The contributions of primary

  7. 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

  8. Modulating effects of maternal fish consumption on the occurrence of respiratory symptoms in early infancy attributed to prenatal exposure to fine particles.

    Science.gov (United States)

    Jedrychowski, Wieslaw; Flak, Elzbieta; Mroz, Elzbieta; Pac, Agnieszka; Jacek, Ryszard; Sochacka-Tatara, Elzbieta; Spengler, John; Rauh, Virginia; Perera, Frederica

    2008-01-01

    The purpose of the study was to test the hypothesis whether infants with higher prenatal exposure to fine particles (PM(2.5)) are at greater risk of developing respiratory symptoms and whether fish consumption in pregnancy may modulate the effect. The study was carried out in a cohort of 465 newborns in Krakow (Poland) who have been followed over the first 2 years of life and for whom data on the occurrence of respiratory symptoms and measurements of personal air monitoring in the second trimester of pregnancy were available. The incidence risk ratio (IRR) of respiratory symptoms due to prenatal PM(2.5) exposure were adjusted for potential confounders (gender of child, breastfeeding, parity, maternal atopy, maternal education as a proxy for the socio-economic status, exposure to postnatal environmental tobacco smoke (ETS), and moulds in households) in the generalized estimating equations (GEE) statistical models. The adjusted risk of coughing was associated significantly with PM(2.5) level (IRR = 2.51; 95% CI: 1.77-3.58), moulds in the household, parity, maternal atopy and postnatal ETS, but was lower in girls, and in infants whose mothers consumed more fish in pregnancy (IRR = 0.85; 95% CI: 0.79-0.91). The risk of wheezing was also correlated significantly with the prenatal exposure to PM(2.5) (IRR = 1.36; 95% CI: 1.29-1.43) but also with the presence of moulds in homes, parity, maternal atopy and postnatal ETS. The occurrence of wheezing was associated inversely with the gender of child, gestational age, and fish consumption in pregnancy (IRR = 0.97; 95% CI: 0.95-0.99). Similarly, the risk of difficult (puffy) breathing increased with prenatal exposure to PM(2.5) (IRR = 1.18; 95% CI: 1.12-1.25) moulds, maternal atopy, and parity. The symptom occurrence was lower in girls and associated inversely with the gestational age, and fish consumption in pregnancy (IRR = 0.94; 95% CI: 0.92-0.97). The results of the study support the hypothesis that fish consumption in

  9. A modeling study of the nonlinear response of fine particles to air pollutant emissions in the Beijing–Tianjin–Hebei region

    Directory of Open Access Journals (Sweden)

    B. Zhao

    2017-10-01

    Full Text Available The Beijing–Tianjin–Hebei (BTH region has been suffering from the most severe fine-particle (PM2. 5 pollution in China, which causes serious health damage and economic loss. Quantifying the source contributions to PM2. 5 concentrations has been a challenging task because of the complicated nonlinear relationships between PM2. 5 concentrations and emissions of multiple pollutants from multiple spatial regions and economic sectors. In this study, we use the extended response surface modeling (ERSM technique to investigate the nonlinear response of PM2. 5 concentrations to emissions of multiple pollutants from different regions and sectors over the BTH region, based on over 1000 simulations by a chemical transport model (CTM. The ERSM-predicted PM2. 5 concentrations agree well with independent CTM simulations, with correlation coefficients larger than 0.99 and mean normalized errors less than 1 %. Using the ERSM technique, we find that, among all air pollutants, primary inorganic PM2. 5 makes the largest contribution (24–36 % to PM2. 5 concentrations. The contribution of primary inorganic PM2. 5 emissions is especially high in heavily polluted winter and is dominated by the industry as well as residential and commercial sectors, which should be prioritized in PM2. 5 control strategies. The total contributions of all precursors (nitrogen oxides, NOx; sulfur dioxides, SO2; ammonia, NH3; non-methane volatile organic compounds, NMVOCs; intermediate-volatility organic compounds, IVOCs; primary organic aerosol, POA to PM2. 5 concentrations range between 31 and 48 %. Among these precursors, PM2. 5 concentrations are primarily sensitive to the emissions of NH3, NMVOC + IVOC, and POA. The sensitivities increase substantially for NH3 and NOx and decrease slightly for POA and NMVOC + IVOC with the increase in the emission reduction ratio, which illustrates the nonlinear relationships between precursor emissions and PM

  10. Resin Characterization

    Science.gov (United States)

    2015-06-01

    to see plastic deformation of the surface. 8.1.4.3 Density: Density using the Archimedes principle (ASTM D 792). 8.1.4.4 Density as a Function of...the cure and postcure, quickly cool the sample to 0 °C or lower the temperature to quench the reaction, and then ramp the temperature at 5 °C/min to...prepared by pouring 10 g of resin into a 30-mL screw-cap scintillation vial and adding appropriate amounts of initiator, catalyst, and inhibitor

  11. Microbiological study of water-softener resins.

    Science.gov (United States)

    Stamm, J M; Engelhard, W E; Parsons, J E

    1969-09-01

    Microbial identification using effluents backflushed from exhausted urban and rural tank resins and cleaned resins containing the sulfonated copolymer of styrene and divinylbenzene (SDB) were completed, along with microbial assessment of the concentrated stock salt brine. Forty-four different bacterial and fungal genera were identified. Extensive biochemical and animal virulence tests completed on one of the six bacterial salt brine isolates indicated a pathogenic staphylococcal strain. The retention of Staphylococcus aureus, a Flavobacterium sp, and Escherichia coli B bacteriophage was demonstrated both by using the nonexhausted sodium-regenerated resin and by using the same resin exchanged with different mono-, di-, and trivalent cations. Effluent counts completed after bacterial seepage through the resins indicated the Pb(++) exchanged resin removed 55% of the bacteria; Na(+), Fe(++), and Al(+++) removed 31 to 36% and Ca(++) and Cu(++) removed about 10 to 15%. Seventy per cent or more of the bacteriophage was removed by Fe(++), Cu(++), and Al(+++), whereas the Ca(++) and Na(++) cations removed 25 to 31%. Over a 77-day period, nonsterile tap water was passed through bacterial seeded and uninoculated SDB (Na) resin columns. Effluent and resin elution counts demonstrated the growth and survival of 2 different bacteria per column. Increased bacterial retention, survival, and multiplication occurred concomitantly with accumulation of organic and inorganic materials and the Ca(++) and Mg(++) cations from the tap water. Furthermore, microbial elution from resin particles taken from column depths of 1, 8, and 16 cm indicated a bacterial diminution with increasing depths.

  12. Relative precision of inhaler aerodynamic particle size distribution (APSD) metrics by full resolution and abbreviated andersen cascade impactors (ACIs): part 2--investigation of bias in extra-fine mass fraction with AIM-HRT impactor.

    Science.gov (United States)

    Mitchell, Jolyon P; Nagel, Mark W; Doyle, Cathy C; Ali, Rubina S; Avvakoumova, Valentina I; Christopher, J David; Quiroz, Jorge; Strickland, Helen; Tougas, Terrence; Lyapustina, Svetlana

    2010-09-01

    The purpose of this study was to resolve an anomalously high measure of extra-fine particle fraction (EPF) determined by the abbreviated cascade impactor possibly relevant for human respiratory tract (AIM-HRT) in the experiment described in Part 1 of this two-part series, in which the relative precision of abbreviated impactors was evaluated in comparison with a full resolution Andersen eight-stage cascade impactor (ACI). Evidence that the surface coating used to mitigate particle bounce was laterally displaced by the flow emerging from the jets of the lower stage was apparent upon microscopic examination of the associated collection plate of the AIM-HRT impactor whose cut point size defines EPF. A filter soaked in surfactant was floated on top of this collection plate, and further measurements were made using the same pressurized metered-dose inhaler-based formulation and following the same procedure as in Part 1. Measures of EPF, fine particle, and coarse particle fractions were comparable with those obtained with the ACI, indicating that the cause of the bias had been identified and removed. When working with abbreviated impactors, this precaution is advised whenever there is evidence that surface coating displacement has occurred, a task that can be readily accomplished by microscopic inspection of all collection plates after allowing the impactor to sample ambient air for a few minutes.

  13. Disinfection of denture base acrylic resin.

    Science.gov (United States)

    Lin, J J; Cameron, S M; Runyan, D A; Craft, D W

    1999-02-01

    During repair or adjustments of acrylic resin removable complete and partial dentures, particles of the acrylic resin from the interior of the prosthesis may expose dental personnel to microbial health hazards if the prosthesis has not been thoroughly disinfected. This study investigates the efficacy of a commercially prepared microbial disinfectant (Alcide) on the external and internal surfaces of acrylic resins. Four groups of acrylic resin were incubated in an experimental model to simulate the oral environment over time. Specimens were treated in 2 groups, disinfected and not disinfected, and then further grouped by breaking and not breaking. Analysis was performed with microbial colony counts, SEM, and statistical analyses. Viable microorganisms still remain on the internal and external surfaces of treated resins. Chlorine dioxide reduces, but does not eliminate, viable microorganisms on these dental prostheses.

  14. Immobilization of spent resin with epoxy resin

    International Nuclear Information System (INIS)

    Gultom, O.; Suryanto; Sayogo; Ramdan

    1997-01-01

    immobilization of spent resin using epoxy resin has been conducted. The spent resin was mixtured with epoxy resin in variation of concentration, i.e., 30, 40, 50, 60, 70 weight percent of spent resin. The mixture were pour into the plastic tube, with a diameter of 40 mm and height of 40 mm. The density, compressive strength and leaching rate were respectively measured by quanta chrome, paul weber apparatus and gamma spectrometer. The results showed that the increasing of waste concentration would be decreased the compressive strength, and increased density by immobilized waste. The leaching rate of 137 Cs from waste product was not detected in experiment (author)

  15. In vitro two-body wear of inlay-onlay composite resin restoratives.

    Science.gov (United States)

    Burgoyne, A R; Nicholls, J I; Brudvik, J S

    1991-02-01

    Inlay-onlay composite resin restorations have been introduced to the profession as alternatives to amalgam and direct composite resins. Two-body wear testing was performed on three inlay-onlay resins and one direct composite resins using a machine designed to produce sliding wear. The composite resins were opposed by human enamel, type III gold alloy, and porcelain. Of the investigated materials, the homogeneously microfilled inlay-onlay material showed significantly less wear. The direct composite resin showed significantly the greatest wear. The hybrid inlay-onlay resins showed intermediate wear. The hybrid inlay-onlay resins and the direct composite (small particle, heavily filled) resin created wear tracks in the opposing surfaces while the homogeneous microfill inlay-onlay resin did not. The depth of the observed wear tracks in the opposing surface was sufficiently substantial to warrant further investigation into the wear of materials that oppose composite resin restorations.

  16. 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.

  17. SEM and elemental analysis of composite resins

    International Nuclear Information System (INIS)

    Hosoda, H.; Yamada, T.; Inokoshi, S.

    1990-01-01

    Twenty-four chemically cured, 21 light-cured anterior, three light-cured anterior/posterior, and 18 light-cured posterior composite resins were examined using scanning electron microscopy, and the elemental composition of their filler particles was analyzed with an energy dispersive electron probe microanalyzer. According to the results obtained, the composite resins were divided into five groups (traditional, microfilled type, submicrofilled type, hybrid type, and semihybrid), with two additional hypothetical categories (microfilled and hybrid). Characteristics of each type were described with clinical indications for selective guidance of respective composite resins for clinical use

  18. EFFECT OF CENTRAL FANS AND IN-DUCT FILTERS ON DEPOSITION RATES OF ULTRAFINE AND FINE PARTICLES IN AN OCCUPIED TOWNHOUSE

    Science.gov (United States)

    Airborne particles are implicated in morbidity and mortality of certain high-risk subpopulations. Exposure to particles occurs mostly indoors, where a main removal mechanism is deposition to surfaces. Deposition can be affected by the use of forced- air circulation through duct...

  19. Magnetic field effect on chemical compositions of spherical Fe/Co fine particles synthesized from a gaseous mixture of iron pentacarbonyl and cobalt tricarbonyl nitrosyl

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Kasai, A.; Šubrt, Jan; Bastl, Zdeněk

    2009-01-01

    Roč. 206, 2-3 (2009), s. 205-212 ISSN 1010-6030 R&D Projects: GA MŠk LC523 Institutional research plan: CEZ:AV0Z40320502; CEZ:AV0Z40400503 Keywords : gas phase photochemical reaction * aerosol particle * particle wire Subject RIV: CA - Inorganic Chemistry Impact factor: 2.553, year: 2009

  20. Characteristics of floc formation of anion and cation exchange resin in precoat filter using powdered ion exchange resin

    International Nuclear Information System (INIS)

    Adachi, Tetsurou; Sawa, Toshio; Shindoh, Toshikazu.

    1989-01-01

    The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of floc formation. The physical, chemical and electrochemical properties of powdered ion exchange resin were measured and the factors related to floc formation of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index. It was found that these factors were mixing ratio, nature of resins and particle size of resins. In addition, it was assumed on the bases of these results that the amount of resin floc was related to sum of the surface electric charges of both resins. The filling ratio of resin floc was related to their product by multiplication and an experimental expression was obtained. The specific settle volume of resin floc could then be simulated by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author)

  1. Characteristics of floc formation of anion and cation exchange resin in precoat filter using powdered ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Tetsurou (Nitto Denko Corp., Ibaraki, Osaka (Japan)); Sawa, Toshio; Shindoh, Toshikazu

    1989-09-01

    The filtration performance of mixed filter aid consisting of powdered anion and cation exchange resins used in the precoat filter is closely related to the characteristics of floc formation. The physical, chemical and electrochemical properties of powdered ion exchange resin were measured and the factors related to floc formation of anion and cation exchange resin were investigated by measuring the specific settle volume of resin floc as an evaluating index. It was found that these factors were mixing ratio, nature of resins and particle size of resins. In addition, it was assumed on the bases of these results that the amount of resin floc was related to sum of the surface electric charges of both resins. The filling ratio of resin floc was related to their product by multiplication and an experimental expression was obtained. The specific settle volume of resin floc could then be simulated by particle size, surface area, ion exchange capacity and degree of ionization of the powdered ion exchange resin. (author).

  2. Color change of composite resins subjected to accelerated artificial aging.

    Science.gov (United States)

    Tornavoi, Denise Cremonezzi; Agnelli, José Augusto Marcondes; Panzeri, Heitor; Dos Reis, Andréa Cândido

    2013-01-01

    The aim of this study was to evaluate the influence of accelerated artificial aging (AAA) on the color change of composite resins used in dentistry. Three composite resins were evaluated: Two microhybrids and one hybrid of higher viscosity, with different amounts and sizes of filler particles, shades C2 and B2. A total of 54 specimens were obtained (18 for each composite resin), made of a Teflon matrix (15 mm in diameter and 2 mm in height). The color measurements were obtained with a Spectrophotometer, (PCB 6807 BYK Gardner) before and after AAA. Data were submitted to the Kolmogorov-Smirnov test (α >0.05), ANOVA and Tukey test (α composite resins with the same shades was analyzed. All composite resins showed unacceptable color changes after AAA (ΔE > 3). Considering the variable ∆E, it was observed that the color tone C2 was already statistically different for the microhybrid composite resin prior to AAA (P composite resins (P composite resin group, before aging the composite resin hybrid of higher viscosity B2 showed the highest color variation rate and microhybrid with zirconium/silica C2 showed the lowest. All composite resins presented unacceptable color changes after 382 h of aging and different composite resins with same hue, presented different colors before being subjected to the aging process (B2 and C2) and after (B2). It was also observed color difference within a group of the same composite resin and same hue.

  3. Adhesion strength improvement of epoxy resin reinforced with nanoelastomeric copolymer

    International Nuclear Information System (INIS)

    Khoee, Sepideh; Hassani, Narges

    2010-01-01

    Research highlights: → Elastomeric nanoparticle (ENP) was prepared via miniemulsion polymerization. → ENP was added to epoxy resin (ER) with different amounts. → The lap shear strength (LSS) of different ENP/ER was measured. → The fractured surfaces were examined by scanning electron microscopy (SEM). - Abstract: Nano-sized copoly(styrene-butylacrylate-ethylenglycoldimethacrylate) (St-BA-EGDMA) particles were added at different contents to improve the toughness of diglycidyl ether of bisphenol A epoxy resin (ER) using piperidine as a curing agent. Transmission electron microscopy (TEM) proved that nanoelastomer was finely dispersed in the epoxy adhesive. To compare the adhesion strength of different adherents utilizing both modified and unmodified epoxy adhesive, the lap shear strength (LSS) test was measured as a function of elastomeric nanoparticles (ENP) amount. Scanning electron microscopy (SEM) and FTIR were used to investigate the interface morphology and chemical composition of adherent and epoxy adhesive. The result indicated that the adhesion strength was increased dramatically by addition of nanoparticles compared with that of pure epoxy adhesive. The highest adhesion strength was obtained with 20 wt% elastomeric nanoparticles. It was found that reinforcement with nanoparticles improved the fracture toughness.

  4. 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 PM 2.5 and PM 10-2.5 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 PM 2.5 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. Copyright © 2016. Published by Elsevier B.V.

  5. Review: Resin Composite Filling

    Directory of Open Access Journals (Sweden)

    Desmond Ng

    2010-02-01

    Full Text Available The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinical procedures involved and finishing and polishing techniques for resin restoration. Although resin composite has aesthetic advantages over amalgam, one of the major disadvantage include polymerization shrinkage and future research is needed on reaction kinetics and viscoelastic behaviour to minimize shrinkage stress.

  6. Review: Resin Composite Filling

    Science.gov (United States)

    Chan, Keith H. S.; Mai, Yanjie; Kim, Harry; Tong, Keith C. T.; Ng, Desmond; Hsiao, Jimmy C. M.

    2010-01-01

    The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinical procedures involved and finishing and polishing techniques for resin restoration. Although resin composite has aesthetic advantages over amalgam, one of the major disadvantage include polymerization shrinkage and future research is needed on reaction kinetics and viscoelastic behaviour to minimize shrinkage stress.

  7. Activated Carbon by Co-pyrolysis and Steam Activation from Particle Board and Melamine Formaldehyde Resin: Production, Adsorption Properties and Techno Economic Evaluation

    Directory of Open Access Journals (Sweden)

    Kenny Vanreppelen

    2013-03-01

    Full Text Available One of the top strategic objectives and research areas in Europe is recovering wood from processing and end of life products. However, there are still several "contaminated" wood products that are not or only partly reused/recycled. Particle board waste which is contaminated with aminoplasts is one of these products. In addition, a considerable amount of aminoplast waste resinis produced for the production of particle board that cannot be re-used or recycled. The chemical properties of these wastes (high nitrogen content of 5.9 wt% and 54.1 wt% for particle board and melamine formaldehyde respectively make them ideal precursors for the production of nitrogenised activated carbon. The profitability of the produced activated carbon is investigated by calculating the net present value, the minimum selling price and performing a Monte Carlo sensitivity analysis. Encouraging results for a profitable production are obtained even though the current assumptions start from a rather pessimistic scenario.

  8. Composite materials based on modified epoxy resin and carbon fiber

    OpenAIRE

    Gonçalez, Viviane; Barcia, Fabio L.; Soares, Bluma G.

    2006-01-01

    Epoxy resin networks have been modified with block copolymer of polybutadiene and bisphenol A diglycidyl ether (DGEBA)-based on epoxy resin. The epoxy resin modified with carboxyl-terminated polybutadiene presented improved impact resistance and outstanding mechanical performance in terms of flexural and tensile properties because of the presence of rubber particles homogeneously dispersed inside the epoxy matrix. This modified system also resulted in an improvement of mechanical properties o...

  9. The kinetics of fossil resin extraction from a flotation concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, L.; Yu, Q.; Miller, J.D. [Univ. of Utah, Salt Lake City, UT (United States)

    1995-11-01

    The kinetics of fossil resin extraction from a flotation concentrate by heptane were investigated as a function of process variables using monosize particles. Experimental results provide for a better understanding of the refining process and the basis for subsequent design and construction of a continuous resin refining circuit. Based on the effect of process variables (particle size, stirring speed, and temperature) the resin extraction rate appears to be controlled by surface solvation phenomena. The initial extraction rate was found to be inversely proportional to the initial particle size and a kinetic model is being developed to describe the experimental results.

  10. Coarse(PM(2.5-10)), fine(PM(2.5)), and ultrafine air pollution particles induce/increase immune costimulatory receptors on human blood-derived monocytes but not on alveolar macrophages.

    Science.gov (United States)

    Becker, Susanne; Soukup, Joleen

    2003-05-09

    Diesel particles have been shown to possess adjuvant activity and influence the development of allergic sensitization. Also, more heterogeneous mixtures of pollution particles have been shown to affect host defenses and development of immunity in animal models. In the present study it was determined whether freshly collected particulate matter (PM(10)) in the size ranges 2.5-10 micro m (PM(2.5-10), coarse), 0.1-2.5 micro m (PM(2.5), fine), and micro m (ultrafine) in diameter affected the development of antigen presenting cells by evaluating the expression of surface receptors involved in T-cell interaction on both human alveolar macrophages (AM) and blood-derived monocytes (Mo). A Mo-AM coculture was exposed to 50 micro g/ml of particles and expression of HLA-DR, CD40, CD80, and CD86 on each cell type was assessed by flow cytometry. Mo upregulated the expression of all four receptors in response to each of the particle fractions, while expression was unaffected in AM. The cells were also exposed to two model air pollution particles, diesel dust and volcanic ash, neither of which affected receptor expression. Furthermore, Mo and AM were separately exposed to the three PM size fractions and supernatants assessed for the T-helper (CD4(+)) lymphocyte chemoattractant interleukin-16 (IL-16). AM, but not Mo, produced IL-16, and this chemoattractant was released only in response to PM(2.5-10). These data suggest that a wide size range of pollution particles contain materials that may promote antigen presentation by Mo, while the capability to specifically recruit CD4(+) lymphocytes is contained in AM stimulated with the coarse PM fraction.

  11. 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.

  12. Resin-Powder Dispenser

    Science.gov (United States)

    Standfield, Clarence E.

    1994-01-01

    Resin-powder dispenser used at NASA's Langley Research Center for processing of composite-material prepregs. Dispenser evenly distributes powder (resin polymer and other matrix materials in powder form) onto wet uncured prepregs. Provides versatility in distribution of solid resin in prepreg operation. Used wherever there is requirement for even, continuous distribution of small amount of powder.

  13. Solid-phase extraction with slurry injection of the resin into ETAAS for trace determination of thallium in natural water

    International Nuclear Information System (INIS)

    Isoshi, Nukatsuka; Hiroyuki, Seitoh; Kunio, Ohzeki

    2004-01-01

    Thallium in natural water samples was determined by electrothermal atomic absorption spectrometry after 1000-fold enrichment by mini solid-phase extraction from a 100-mL sample solution. A TI-pyrrolidine-1-carbodithioate complex formed in a sample solution of pH 1.6 was extracted on fine particles of a cellulose nitrate resin dispersed in the sample solution. The cellulose nitrate resin was then collected on a membrane filter (25 mm ) by filtration under suction using a glass funnel with an effective filtration area of 0.64 cm 2 . As a result, a circular thin layer of the resin phase with a diameter of 9 mm was obtained. Then the resin phase was carved out by an acrylate resin puncher with a 10-mm hole to put it into a sample cup containing 100 μL of 10 mM HNO 3 containing 0.5 mM NaCl. The resin phase was suspended in the solution by ultrasonication. 1000-fold enrichment was thus attained within 15 min, and the suspension was delivered to electrothermal atomic absorption spectrometry. The linear calibration graph was obtained in the range of 0-4 ng of TI in 100 mL of a sample solution. The detection limit obtained by 3 σ method was 0.19 ng. The proposed method was applied to the determination of TI in natural water samples. The results showed the concentration of TI in seawater was 12.1 ± 1.8 pg mL -1 for the calibration graph method and 12.6 ± 1.4 pg mL -1 for the standard addition method. A snowmelt sample contained 20.7 ± 1.0 pg mL -1 of TI. (author)

  14. Effect of 2-propenyltrimethylsilane and magnetic field effect on photochemical Fe/Co fine particle formation from a ternary gaseous mixture

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Hattori, K.; Šubrt, Jan

    2011-01-01

    Roč. 218, č. 1 (2011), s. 111-116 ISSN 1010-6030 Institutional research plan: CEZ:AV0Z40320502 Keywords : gas phase photochemical reaction * aerosol particle * magnetic field effect * iron pentacarbonyl * cobalt tricarbonyl nitrosyl Subject RIV: CA - Inorganic Chemistry Impact factor: 2.421, year: 2011

  15. Synoptic conditions of fine-particle transport to the last interglacial Red Sea-Dead Sea from Nd-Sr compositions of sediment cores

    Science.gov (United States)

    Palchan, Daniel; Stein, Mordechai; Goldstein, Steven L.; Almogi-Labin, Ahuva; Tirosh, Ofir; Erel, Yigal

    2018-01-01

    The sediments deposited at the depocenter of the Dead Sea comprise high-resolution archive of hydrological changes in the lake's watershed and record the desert dust transport to the region. This paper reconstructs the dust transport to the region during the termination of glacial Marine Isotope Stage 6 (MIS 6; ∼135-129 ka) and the last interglacial peak period (MIS5e, ∼129-116 ka). We use chemical and Nd and Sr isotope compositions of fine detritus material recovered from sediment core drilled at the deepest floor of the Dead Sea. The data is integrated with data achieved from cores drilled at the floor of the Red Sea, thus, forming a Red Sea-Dead Sea transect extending from the desert belt to the Mediterranean climate zone. The Dead Sea accumulated flood sediments derived from three regional surface cover types: settled desert dust, mountain loess-soils and loess-soils filling valleys in the Dead Sea watershed termed here "Valley Loess". The Valley Loess shows a distinct 87Sr/86Sr ratio of 0.7081 ± 1, inherited from dissolved detrital calcites that originate from dried waterbodies in the Sahara and are transported with the dust to the entire transect. Our hydro-climate and synoptic conditions reconstruction illustrates the following history: During glacial period MIS6, Mediterranean cyclones governed the transport of Saharan dust and rains to the Dead Sea watershed, driving the development of both mountain soils and Valley Loess. Then, at Heinrich event 11, dry western winds blew Saharan dust over the entire Red Sea - Dead Sea transect marking latitudinal expansion of the desert belt. Later, when global sea-level rose, the Dead Sea watershed went through extreme aridity, the lake retreated, depositing salt and accumulating fine detritus of the Valley Loess. During peak interglacial MIS 5e, enhanced flooding activity flushed the mountain soils and fine detritus from all around the Dead Sea and Red Sea, marking a significant "contraction" of the desert belt

  16. Resin screening for the removal of pyridine-derivatives from waste-water by solvent impregnated resin technology

    NARCIS (Netherlands)

    Bokhove, J.; Schuur, Boelo; de Haan, A.B.

    2013-01-01

    The selective removal of pyridine derivatives by solvent impregnated resins has been studied. A solvent impregnated resin consists of a macro-porous particle that is impregnated with a solvent. This technology allows the use liquid–liquid extraction in fixed-bed operation, and prevents problems like

  17. Mechanistic understanding of fouling of protein A chromatography resin.

    Science.gov (United States)

    Pathak, Mili; Rathore, Anurag S

    2016-08-12

    This paper aims to provide a thorough understanding of how fouling of Protein A resin takes place. Binding and mass transport properties of widely used agarose-based Protein A resin, MabSelect SuRe™, have been examined to understand the mechanism of resin fouling. There could be various factors that impact resin fouling. These include product/impurity build-up due to components in the feed material and ligand degradation due to the use of harsh buffers. To unravel their contributions, cycling studies were performed with and without product loading. The results presented in this paper provide a lucid understanding of the causative factors that limit Protein A chromatographic resin lifetime. The capacity fall for protein A resin at the end of 100th cycle due to use of feed material was found to be five times greater than that without using feed material. Compared to the fresh resin, the cycled resin samples shows 24% reduction in particle porosity and 51% reduction in pore mass transfer coefficient. Transmission electron microscopy (TEM) was used to qualitatively monitor accumulation of foulants on the cycled resin. Fouled resin sample contained a dense residue in the interior and exterior of resin particle both as a film at the bead surface and as granules. The surface activation energy increased five times in the case of fouled resin sample. The major event in fouling was identified as the non-specific adsorption of the feed material components on resin, signaling that pore diffusion is the rate limiting step. It is anticipated that these findings will assist in development of a more robust and economical downstream manufacturing process for monoclonal antibody purification. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Calcination and solid state reaction of ceramic-forming components to provide single-phase superconducting materials having fine particle size

    Science.gov (United States)

    Balachandran, Uthamalingam; Poeppel, Roger B.; Emerson, James E.; Johnson, Stanley A.

    1992-01-01

    An improved method for the preparation of single phase, fine grained ceramic materials from precursor powder mixtures where at least one of the components of the mixture is an alkali earth carbonate. The process consists of heating the precursor powders in a partial vacuum under flowing oxygen and under conditions where the partial pressure of CO.sub.2 evolved during the calcination is kept to a very low level relative to the oxygen. The process has been found particularly suitable for the preparation of high temperature copper oxide superconducting materials such as YBa.sub.2 Cu.sub.3 O.sub.x "123" and YBa.sub.2 Cu.sub.4 O.sub.8 "124".

  19. Fine chemistry

    International Nuclear Information System (INIS)

    Laszlo, P.

    1988-01-01

    The 1988 progress report of the Fine Chemistry laboratory (Polytechnic School, France) is presented. The research programs are centered on the renewal of the organic chemistry most important reactions and on the invention of new, highly efficient and highly selective reactions, by applying low cost reagents and solvents. An important research domain concerns the study and fabrication of new catalysts. They are obtained by means of the reactive sputtering of the metals and metal oxydes thin films. The Monte Carlo simulations of the long-range electrostatic interaction in a clay and the obtention of acrylamides from anhydrous or acrylic ester are summarized. Moreover, the results obtained in the field of catalysis are also given. The published papers and the congress communications are included [fr

  20. Protein a resin lifetime study: Evaluation of protein a resin performance with a model-based approach in continuous capture.

    Science.gov (United States)

    Behere, Ketki; Cha, Bumjoon; Yoon, Seongkyu

    2018-01-22

    A modified shrinking core model (MSCM) has been used to describe the mechanism for the degradation of Protein A resin particles taking place under continuous chromatographic operation. The model is based on the hypothetical shrinkage of the boundary layer of the resin particles, which house the active Protein A ligands within their pores. The caustic during the sanitization phase of chromatography has been determined to cause the Protein A ligand degradation. Protein A resins provided by manufacturers possess unique caustic stability, which has been used in MSCM to appraise the ligand degradation. The kinetic model utilized semiempirical parameters including diffusion constant, rate constant, stoichiometric factor, and reaction order. The parameters were estimated from column breakthrough experiments to simulate continuous Protein A chromatography for three distinct resins. The reaction order has been identified as the key parameter for predicting the degradation kinetics. The recorded reaction orders vary for three different resins with the resin B showing the highest reaction order of 4 and lowest being 1.65 for the resin C. The model can predict the effects of caustic on resin performance and displayed that minimal degradation of the resins A and B occurred, when exposed to 0.1 N and 0.2N NaOH, retaining up to 96% binding capacity after 240 cycles. The adsorption study conducted for the resin B demonstrated the dynamic physical and chemical changes transpiring through the life cycle of the resin, further supported the degradation model. The performance data demonstrate that the resin B exhibits the desirable performance, with higher reaction order indicating slower resin degradation, higher binding capacities, and increased sustenance of this binding capacity for extended duration. The degradation model can be extended to build effective cleaning strategies for continuous downstream processing.

  1. 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.)

  2. Mechanical properties and strengthening mechanism of epoxy resin reinforced with nano-SiO2 particles and multi-walled carbon nanotubes

    Science.gov (United States)

    Xiao, Chufan; Tan, Yefa; Yang, Xupu; Xu, Ting; Wang, Lulu; Qi, Zehao

    2018-03-01

    Nano-SiO2 particles and MWCNTs were used to reinforce the EPs. The mechanical properties of the composites and the strengthening mechanisms of nano-SiO2 and MWCNTs on the mechanical properties of epoxy composites were studied. The results show that the mechanical properties of the reinforced epoxy composites are greatly improved. Especially, nano-SiO2/MWCNTs/EP composites exhibit the most excellent mechanical properties. The synergistic strengthening mechanisms of nano-SiO2 and MWCNTs on the EP are the micro plastic deformation effect, micro-cracks and their divarication effect, and the pull-out effect of MWCNTs in EP matrix, which can reduce the extent of stress concentration and absorb more energy.

  3. 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

    2017-06-01

    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 (PM 2.5 ) 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 PM 2.5 particles. The compositional and structural features of water-soluble and -insoluble organic compounds from PM 2.5 particles are important for understanding the potential impacts of aerosol-carried organic substances on human health and global ecosystems in future toxicological studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. High levels of ammonia do not raise fine particle pH sufficiently to yield nitrogen oxide-dominated sulfate production.

    Science.gov (United States)

    Guo, Hongyu; Weber, Rodney J; Nenes, Athanasios

    2017-09-21

    High levels of ammonia (NH 3 ) have been suggested to elevate ambient particle pH levels to near neutral acidity (pH = 7), a condition that promotes rapid SO 2 oxidation by NO 2 to form aerosol sulfate concentration consistent with "London fog" levels. This postulation is tested using aerosol data from representative sites around the world to conduct a thorough thermodynamic analysis of aerosol pH and its sensitivity to NH 3 levels. We find that particle pH, regardless of ammonia levels, is always acidic even for the unusually high NH 3 levels found in Beijing (pH = 4.5) and Xi'an (pH = 5), locations where sulfate production from NO x is proposed. Therefore, major sulfate oxidation through a NO 2 -mediated pathway is not likely in China, or any other region of the world (e.g., US, Mediterranean) where the aerosol is consistently more acidic. The limited alkalinity from the carbonate buffer in dust and seasalt can provide the only likely set of conditions where NO 2 -mediated oxidation of SO 2 outcompetes with other well-established pathways. The mildly acidic levels associated with excessive amounts of ammonia can promote high rates of SO 2 oxidation through transition metal chemistry, this may be an alternative important aerosol chemical contributor to the extreme pollution events.

  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. 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

  7. Effects of solubility of urban air fine and coarse particles on cytotoxic and inflammatory responses in RAW 264.7 macrophage cell line

    International Nuclear Information System (INIS)

    Jalava, Pasi I.; Salonen, Raimo O.; Pennanen, Arto S.; Happo, Mikko S.; Penttinen, Piia; Haelinen, Arja I.; Sillanpaeae, Markus; Hillamo, Risto; Hirvonen, Maija-Riitta

    2008-01-01

    We investigated the inflammatory and cytotoxic activities of the water-soluble and -insoluble as well as organic-solvent-soluble and -insoluble fractions of urban air fine (PM 2.5-0.2 ) and coarse (PM 10-2.5 ) particulate samples. The samples were collected with a high volume cascade impactor (HVCI) in 7-week sampling campaigns of selected seasons in six European cities. Mouse macrophage cells (RAW 264.7) were exposed to the samples for 24 h. The production of nitric oxide (NO) and proinflammatory cytokines (TNFα, IL-6), and cytotoxicity (MTT-test, apoptosis, cell cycle) were measured. The inflammatory and cytotoxic responses in both size ranges were mostly associated with the insoluble particulate fractions. However, both the water- and organic-solvent-soluble particulate fractions induced TNFα production and apoptosis and had some other cytotoxic effects. Soil-derived water-soluble and -insoluble components of the chemical PM 2.5-0.2 mass closure had consistent positive correlations with the responses, while the correlations were negative with the secondary inorganic anions (NO 3 - , NH 4 + , non-sea-salt SO 4 2- ) and particulate organic matter (POM). With the PM 10-2.5 samples, sea salt and soluble soil components correlated positively with the induced toxic responses. In this size range, a possible underestimation of the insoluble, soil-related compounds containing Si and Ca, and biological components of POM, increased uncertainties in the evaluation of associations of the mass closure components with the responses. It is concluded that insoluble components of the complex urban air particulate mixture exert the highest inflammatory and cytotoxic activities in the macrophage cell line but, at the same time, they may operate as carriers for active water- and lipid-soluble components

  8. Analysis system of submicron particle tracks in the fine-grained nuclear emulsion by a combination of hard x-ray and optical microscopy

    International Nuclear Information System (INIS)

    Naka, T.; Asada, T.; Yoshimoto, M.; Katsuragawa, T.; Tawara, Y.; Umemoto, A.; Suzuki, Y.; Terada, Y.; Takeuchi, A.; Uesugi, K.; Kimura, M.

    2015-01-01

    Analyses of nuclear emulsion detectors that can detect and identify charged particles or radiation as tracks have typically utilized optical microscope systems because the targets have lengths from several μm to more than 1000 μm. For recent new nuclear emulsion detectors that can detect tracks of submicron length or less, the current readout systems are insufficient due to their poor resolution. In this study, we developed a new system and method using an optical microscope system for rough candidate selection and the hard X-ray microscope system at SPring-8 for high-precision analysis with a resolution of better than 70 nm resolution. Furthermore, we demonstrated the analysis of submicron-length tracks with a matching efficiency of more than 99% and position accuracy of better than 5 μm. This system is now running semi-automatically

  9. Source apportionment of fine particles and its chemical components over the Yangtze River Delta, China during a heavy haze pollution episode

    Science.gov (United States)

    Li, L.; An, J. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Lu, Q.; Lin, L.; Wang, Y. J.; Tao, S. K.; Qiao, L. P.; Zhu, S. H.; Chen, C. H.

    2015-12-01

    contributors to organic carbon. Results show that the Yangtze River Delta region should focus on the joint pollution control of industrial processing, combustion emissions, mobile source emissions, and fugitive dust. Regional transport of air pollution among the cities are prominent, and the implementation of regional joint prevention and control of air pollution will help to alleviate fine particulate matter concentrations under heavy pollution case significantly.

  10. Synoptic conditions of fine-particle transport to the last interglacial Red Sea -Dead Sea from Nd-Sr compositions of sediment cores

    Science.gov (United States)

    Stein, M.; Palchan, D.; Goldstein, S. L.; Almogi-Labin, A.; Tirosh, O.; Erel, Y.

    2017-12-01

    The last interglacial peak, Marine Isotope Stage 5e (MIS 5e), was associated with stronger northern hemisphere insolation, higher global sea levels and higher average global temperatures compared to the Holocene, and is considered as an analogue for a future warming world. In this perspective the present-day areas of the Sahara - Arabia deserts (the "desert belt") are of special interest since their margins are densely inhabited and global climate models predict enhanced aridity in these regions due to future warming. The Red Sea situated at the midst of the desert belt and the Dead Sea at the northern fringe of the desert belt comprise sensitive monitors for past hydroclimate changes in the Red Sea-Levant regions as global climate shifted from glacial to interglacial conditions. Here, we reconstruct the synoptic conditions that controlled desert dust transport to the Red Sea and the Dead Sea during MIS5e. The reconstruction is based on Nd-Sr isotopes and chemical composition of carbonate-free detritus recovered from sediment cores drilled at the deep floors of these water-bodies combined with data of contemporaneous dust storms transporting dust to the lake and sea floors. During Termination 2 ( 134-130 ka) the Sahara, Nile River desiccated and the Dead Sea watershed were under extreme dry conditions manifested by lake level drop, deposition of salt and enhanced transport of Sahara dusts to the entire studied transect. At the peak of the interglacial MIS 5e ( 130-120 ka), enhanced flooding activity mobilized local fine detritus from the surroundings of the Red Sea and the Dead Sea watershed into the water-bodies. This interval coincided with the Sapropel event S5 in the Mediterranean that responded to enhanced monsoon rains at the heads of the Blue Nile River. At the end of MIS 5e ( 120-116 ka) the effect of the regional floods faded and the Dead Sea and Red Sea areas re-entered sever arid conditions with salt deposition at the Dead Sea. Overall, the desert

  11. Quality of skin as a barrier to ultra-fine particles. Contribution of the IBA group to the NANODERM EU-5 project in 2003-2004

    International Nuclear Information System (INIS)

    Kertesz, Zs.; Szikszai, Z.; Kiss, A.Z.

    2004-01-01

    Complete text of publication follows. Micronised titanium-, zinc- or silicon-oxide is a widely used physical photoprotective agent as a component of various cosmetic products. Due to the small particle size (down to 15 nm) it is supposed, that the particles may pass through the uppermost horny skin layer, and penetrate into deeper vital skin layers. However, only a few experiments have been carried out on its penetration through the human epidermal barrier and its possible biological effects in vivo and in vitro, using the tape stripping method which has no lateral and limited depth resolution. A consortium consisting of 12 European universities and scientific institutes has been established under the leadership of the Fakultat fuer Physik und Geowissenchaft Universitat Leipzig, whose goal is to get quantitative information on the penetration of ultrafine particles in all strata of skin, on their penetration pathways as well as on their impact on human health [1]. The IBA group of the Atomki takes part in this project as a subcontractor of the Department of Dermatology, University of Debrecen, Hungary. Ion microscopy, electron microscopy and autoradiography are used to trace the penetration of the nanoparticles into the skin layers, molecular and cell-biological methods are applied to assess the skin response and activation of dermal cells. The IBA group of the Atomki takes part in WP3: Ion Microscopy Work Package together with five other nuclear microprobe laboratories. The participants provide quantitative elemental composition in all strata of skin with detection limits of about 1 μg/g and lateral resolution of 1-2 μm by applying various ion beam analytical techniques. Samples investigated by ion microscopy are 14-16 μm thick cryo-fixed freeze-dried sections of porcine and human skin. Since the sample preparation requires completely different treatment for ion microscopy than for conventional microscopy, the members of the IBA group, who already have

  12. Arsenic Removal from Water Using Various Adsorbents: Magnetic Ion Exchange Resins, Hydrous Ion Oxide Particles, Granular Ferric Hydroxide, Activated Alumina, Sulfur Modified Iron, and Iron Oxide-Coated Microsand

    KAUST Repository

    Sinha, Shahnawaz

    2011-09-30

    The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic - rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of C eq = 10 μg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95 % .

  13. 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. Copyright © 2016. Published by Elsevier B.V.

  14. Observation of fine particle concentration and its chemical characteristics in central region of Korea during KORUS-AQ pre-campaign

    Science.gov (United States)

    Lyu, Y.; Lee, M.; Hwang, T.; Hong, Y.; Hong, J.

    2015-12-01

    The Central Region super site is one of the 6 super sites operated in Korean peninsula by Ministry of Environment Korea and monitor air quality of central district of Korea continuously and intensively. Located 160km south of Seoul, this site represents an urban site surrounded by residential, commercial area and an 8-lane road cross section which is one of the most crowed main roads in this area. This site also plays a significant role especially in tracing air pollutants flowing through the West Sea from China. During Korus-AQ(Korea-US Air Quality Study) pre-campaign conducted from 18th May to 12th June, PM2.5 and PM10 mass concentration using BAM1020 (MetOne), PM2.5bounded ion concentration using AIM (URG), metal concentrations using XRF (Cooper), organic and elemental carbon contents using SOCEC (Sunset), light scattering coefficient using Nephelometer (TSI) and meteorological parameters were continuously measured at this super site. PM2.5 and PM10 average concentrations were 31 and 49 ug/m3 with 0.63 fine to course ratio, which were relatively lower than those of annual average concentration of 2014 (39 and 58 ug/m3, respectively). The chemical composition of PM2.5 were determined as ion(46%), TC(37%), CM(2%), TM(0.1%) and unknown(15%). The average concentration of organic and elemental carbon were 5.6 and 1.8 ug/m3 which were similar lever to average of 2014 (5.9 ug/m3, 1.71 ug/m3, respectively). And the metal concentration including Pb(12.5 ng/m3), Fe(151.7 ng/m3), Ca(26.2 ng/m3), Ti(5.2 ng/m3), Cd(4.1 ng/m3) were significantly lower than those of 2014(31.4 ng/m3, 242.1 ng/m3, 167.9 ng/m3, 13.0 ng/m3, 8.3 ng/m3, respectively). However, the average concentration of sulfate was 6.3 ug/m3 which was 43% higher than that of 2014 (4.4 ug/m3). Overall aerosol and its component's concentrations except for secondary sulfate have been decreased since it was late spring and early summer in Korea during pre-campaign and usually in this season aerosol level is

  15. Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material.

    Science.gov (United States)

    Erdemir, Ugur; Sancakli, Hande Sar; Sancakli, Erkan; Eren, Meltem Mert; Ozel, Sevda; Yucel, Taner; Yildiz, Esra

    2014-12-01

    The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of 6 mm × 4 mm and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with 30 µm silica oxide particles (Cojet™ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at α=.05. Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (Presin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.

  16. Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material

    Science.gov (United States)

    Sancakli, Hande Sar; Sancakli, Erkan; Eren, Meltem Mert; Ozel, Sevda; Yucel, Taner; Yildiz, Esra

    2014-01-01

    PURPOSE The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of 6 mm × 4 mm and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with 30 µm silica oxide particles (Cojet™ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at α=.05. RESULTS Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (Presin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used. PMID:25551002

  17. Influence of the molecular structure on hydrolyzability of epoxy resins

    International Nuclear Information System (INIS)

    Pays, M.F.

    1996-01-01

    EDF has decided to use glass reinforced composites for certain pipework in Pressurized Water Reactors (service water, emergency-supplied service water, fine pipe works, etc...) as a replacement for traditional materials. In practice, steel is prone to rapid corrosion in these circuits; introducing composites could prove economically viable if their long term behaviour can be demonstrated. However, composite materials can undergo deterioration in service through hydrolysis of the resin or the fibre-matrix interface. Different resins can be chosen depending on the programmed use. A first study has covered the hydrolyzability of polyester and vinyl ester resins. The present document undertakes the resistance to hydrolysis of epoxy resins, concentrating on those reputed to withstand high temperatures. This research uses model monomer, linking the molecular structure of the materials to their resistance to hydrolysis. (author)

  18. Reduction of polyester resin shrinkage by means of epoxy resin

    International Nuclear Information System (INIS)

    Pietrzak, M.; Brzostowski, A.

    1981-01-01

    An attempt was made to decrease the shrinkage of unsaturated polyester resin, taking place during radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified with cinnamic and acrylic acids. A composition of 90 parts of polyester resin, 10 parts of epoxy resin modified with cinnamic acid, and 150 parts of a silica filler showed a volume shrinkage of 1.2%. (author)

  19. Cleaning and dewatering fine coal

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Roe-Hoan; Eraydin, Mert K.; Freeland, Chad

    2017-10-17

    Fine coal is cleaned of its mineral matter impurities and dewatered by mixing the aqueous slurry containing both with a hydrophobic liquid, subjecting the mixture to a phase separation. The resulting hydrophobic liquid phase contains coal particles free of surface moisture and droplets of water stabilized by coal particles, while the aqueous phase contains the mineral matter. By separating the entrained water droplets from the coal particles mechanically, a clean coal product of substantially reduced mineral matter and moisture contents is obtained. The spent hydrophobic liquid is separated from the clean coal product and recycled. The process can also be used to separate one type of hydrophilic particles from another by selectively hydrophobizing one.

  20. Resin composite repair: Quantitative microleakage evaluation of resin-resin and resin-tooth interfaces with different surface treatments

    OpenAIRE

    Celik, Cigdem; Cehreli, Sevi Burcak; Arhun, Neslihan

    2015-01-01

    Objective: The aim was to evaluate the effect of different adhesive systems and surface treatments on the integrity of resin-resin and resin-tooth interfaces after partial removal of preexisting resin composites using quantitative image analysis for microleakage testing protocol. Materials and Methods: A total of 80 human molar teeth were restored with either of the resin composites (Filtek Z250/GrandioSO) occlusally. The teeth were thermocycled (1000?). Mesial and distal 1/3 parts of the res...

  1. Synthesis method of asymmetric gold particles.

    Science.gov (United States)

    Jun, Bong-Hyun; Murata, Michael; Hahm, Eunil; Lee, Luke P

    2017-06-07

    Asymmetric particles can exhibit unique properties. However, reported synthesis methods for asymmetric particles hinder their application because these methods have a limited scale and lack the ability to afford particles of varied shapes. Herein, we report a novel synthetic method which has the potential to produce large quantities of asymmetric particles. Asymmetric rose-shaped gold particles were fabricated as a proof of concept experiment. First, silica nanoparticles (NPs) were bound to a hydrophobic micro-sized polymer containing 2-chlorotritylchloride linkers (2-CTC resin). Then, half-planar gold particles with rose-shaped and polyhedral structures were prepared on the silica particles on the 2-CTC resin. Particle size was controlled by the concentration of the gold source. The asymmetric particles were easily cleaved from the resin without aggregation. We confirmed that gold was grown on the silica NPs. This facile method for synthesizing asymmetric particles has great potential for materials science.

  2. A Study on Tensile Behavior and Water Uptake of Wood Powder-Composites Based on Epoxy and Unsaturated Polyester Resins

    OpenAIRE

    Amir hossein Pirayeshfar; M.Mahdi Jalili; Yahya Musavi

    2013-01-01

    In this study, two kinds of epoxy resins (i.e. high-viscosity and low-viscosity) as well as one polyester resin (orthophthalic grade) were selected and examined as pure resins and also as a polymeric matrix for producing wood-composites. In this study, tensile properties, water uptake, and degradation of samples in water were also investigated. The results show that addition of wood particles to the thermoset resins strongly impresses on their tensile behavior and water uptake. Tensile studie...

  3. 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.

  4. Development of Thermal Spraying and Coating Techniques by Using Thixotropic Slurries Including Metals and Ceramics Particles

    International Nuclear Information System (INIS)

    Kirihara, S; Tasaki, S; Itakura, Y

    2013-01-01

    Thermal nanoparticles coating and microlines patterning were newly developed as novel technologies to fabricate fine ceramics layers and geometrical intermetallics patterns for mechanical properties modulations of practical alloys substrates. Nanometer sized alumina particles were dispersed into acrylic liquid resins, and the obtained slurries were sputtered by using compressed air jet. The slurry mists could blow into the arc plasma with argon gas spraying. On stainless steels substrates, the fine surface layers with high wear resistance were formed. In cross sectional microstructures of the coated layers, micromater sized cracks or pores were not observed. Subsequently, pure aluminum particles were dispersed into photo solidified acrylic resins, and the slurry was spread on the stainless steel substrates by using a mechanical knife blade. On the substrates, microline patterns with self similar fractal structures were drawn and fixed by using scanning of an ultra violet laser beam. The patterned pure metal particles were heated by the argon arc plasma spray assisting, and the intermetallics or alloys phases with high hardness were created through reaction diffusions. Microstructures in the coated layers and the patterned lines were observed by using a scanning electron microscopy.

  5. Macroporous resin purification of peptides with umami taste from soy sauce.

    Science.gov (United States)

    Zhuang, Mingzhu; Zhao, Mouming; Lin, Lianzhu; Dong, Yi; Chen, Huiping; Feng, Mengying; Sun-Waterhouse, Dongxiao; Su, Guowan

    2016-01-01

    In this study, the performance and separation characteristics of four macroporous resins for purifying umami peptides from soy sauce were examined. Results showed that the resins could separate the peptides of soy sauce, and the particle diffusion kinetics model was suitable for describing the whole exothermic (ΔH resins, while the pseudo-second-order kinetics model accurately described the XAD-16 and HP-2 MGL resins. Furthermore, the adsorption processes of the peptides followed the Freundlich model. The XAD-16 resin was the most effective resin for the enrichment of peptides due to its high adsorption and total desorption capacities. Interestingly, the umami peptides were enriched in the deionized water fraction. This study provides new insights into exploring performance and separation characteristics of macroporous resins on soy sauce, and indicated that peptide may be the contributor to the umami taste in Chinese soy sauce. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. 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

  7. A flowrate measurement method by counting of radioactive particles suspended in a liquid

    International Nuclear Information System (INIS)

    Daniel, G.

    1983-04-01

    By external counting of fine #betta# emitting radioactive particles suspended in a liquid, the flowrate in a system of pipes can be measured. The study comprises three phases: 1. - The hydraulic validity of the method is demonstrated in laminar as well as in turbulent flow under certain conditions of particles size and density and of liquid viscosity. 2. - Radioactive labelling of microspheres of serumalbumin or ion exchange resins with indium 113m delivered by a generator Tin 113 → Indium 113m. 3. - Counting with a scintillation detector: a method of threshold overstepping is experimented with a mechanical or electronic simulator; the statistical study of particle superposition under the detector enables a correction for the resulting counting losses to be proposed. The method provides absolute measurements, but is particularly suitable to measure relative flowrates in a hydraulic network. It can be continuous and does not perturb the flow and the network. The accuracy of the method is analysed in details [fr

  8. Preparation and characterization of Bismaleimide resin/titania nanocomposites via sol-gel process

    OpenAIRE

    Lu, Guotao; Huang, Ying

    2013-01-01

    Bismaleimide (BMI) resin/ titania nanocomposites were synthesized from allylated-phenolic modified bismaleimide resin and TiO2 via the sol-gel process of tetrabutyltitanate (Ti(OnBu)4, TBT). These nanocomposite materials were characterized by FT-IR, XRD, FE-SEM, TGA and DMA. It was found that the nano-scale TiO2 particles were formed in the AP-BMI resin matrix, and the average primary particle size of the dispersed phase in the nanocomposites was less than 100nm, but the particle aggregates w...

  9. 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.

  10. Electrodeposition of Asphaltenes. 2. Effect of Resins and Additives

    DEFF Research Database (Denmark)

    Khvostichenko, Daria S; Andersen, Simon Ivar

    2010-01-01

    Electrodeposition of asphaltenes from oil/heptane, asphaltene/heptane, and asphaltene/heptane/additive mixtures has been investigated. Toluene, native petroleum resins, and a synthetic asphaltene dispersant, p-nonylphenol, were used as additives. The addition of these components led to partial...... of preparation of the mixture and the toluene content. Introduction of petroleum resins into asphaltene/heptane mixtures resulted in neutralization of the asphaltene particle charge. The addition of p-nonylphenol to asphaltene suspensions in heptane did not alter the charge of asphaltene particles. Current...

  11. Process for preparing fine grain silicon carbide powder

    Science.gov (United States)

    Wei, G.C.

    Finely divided silicon carbide powder is obtained by mixing colloidal silica and unreacted phenolic resin in either acetone or methanol, evaporating solvent from the obtained solution to form a gel, drying and calcining the gel to polymerize the phenolic resin therein, pyrolyzing the dried and calcined gel at a temperature in the range of 500 to 1000/sup 0/C, and reacting silicon and carbon in the pyrolyzed gel at a temperature in the range of 1550 to 1700/sup 0/C to form the powder.

  12. On airborne nano/micro-sized wear particles released from low-metallic automotive brakes

    International Nuclear Information System (INIS)

    Kukutschova, Jana; Moravec, Pavel; Tomasek, Vladimir; Matejka, Vlastimil; Smolik, Jiri; Schwarz, Jaroslav; Seidlerova, Jana; Safarova, Klara; Filip, Peter

    2011-01-01

    The paper addresses the wear particles released from commercially available 'low-metallic' automotive brake pads subjected to brake dynamometer tests. Particle size distribution was measured in situ and the generated particles were collected. The collected fractions and the original bulk material were analyzed using several chemical and microscopic techniques. The experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm were released into the air. The numbers of nanoparticles (<100 nm) were by three orders of magnitude larger when compared to the microparticles. A significant release of nanoparticles was measured when the average temperature of the rotor reached 300 deg. C, the combustion initiation temperature of organics present in brakes. In contrast to particle size distribution data, the microscopic analysis revealed the presence of nanoparticles, mostly in the form of agglomerates, in all captured fractions. The majority of elements present in the bulk material were also detected in the ultra-fine fraction of the wear particles. - Research highlights: → Wear of low-metallic friction composite produces airborne nano-sized particles. → Nano-sized particles contain carbon black and metallic compounds. → Carbon black nano-sized particles are related to resin degradation. → Number of nanoparticles higher by three orders of magnitude than microparticles. - Braking of automobiles may contribute to nano-particulate air pollution caused by friction processes associated with wear of low-metallic brake pads.

  13. Contact allergy to epoxy resin

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil

    2012-01-01

    to epoxy resin remained stable over the study period. Of the patients with an epoxy resin-positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one-third did not use protective gloves and only 50.5% (48) had participated...

  14. Degradation, Fatigue, and Failure of Resin Dental Composite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, J.L. (UIC)

    2008-11-03

    The intent of this article is to review the numerous factors that affect the mechanical properties of particle- or fiber-filler-containing indirect dental resin composite materials. The focus will be on the effects of degradation due to aging in different media, mainly water and water and ethanol, cyclic loading, and mixed-mode loading on flexure strength and fracture toughness. Several selected papers will be examined in detail with respect to mixed and cyclic loading, and 3D tomography with multi-axial compression specimens. The main cause of failure, for most dental resin composites, is the breakdown of the resin matrix and/or the interface between the filler and the resin matrix. In clinical studies, it appears that failure in the first 5 years is a restoration issue (technique or material selection); after that time period, failure most often results from secondary decay.

  15. Enhancement of adhesion between resin coating materials and resin cements.

    Science.gov (United States)

    Udo, Tomoaki; Nikaido, Toru; Ikeda, Masaomi; Weerasinghe, Dinesh S; Harada, Naoko; Foxton, Richard M; Tagami, Junji

    2007-07-01

    Resin coating technique is a unique method that improves the dentin bond strength of resin cements in indirect restorations. However, the weak link of a specimen bonded using the resin coating technique was reported to be the bonded interface between the resin coating material and resin cement. The purpose of this study, therefore, was to enhance the bonding performance between a resin coating material and a resin cement. Two light-cured flowable composites, Protect Liner F and Clearfil Flow FX, were used as coating materials, and two dual-cure composite materials, Panavia F 2.0 and Clearfil DC Core Automix, were used as resin cements. The ultimate tensile strength of each material and the microtensile bond strengths of the bonded specimens of resin coating material and resin cement were measured using a crosshead speed of 1.0 mm/min. Three-way ANOVA (p=0.05) revealed that the highest microtensile bond strength was obtained using a combination of Clearfil Flow FX and Clearfil DC Core Automix, and when the surface of the coating material was treated with ED Primer II. It was strongly suggested that materials with a higher ultimate tensile strength, when used in both resin coating and cementation, could enhance the bond strength between the two.

  16. Resin impregnation process for producing a resin-fiber composite

    Science.gov (United States)

    Palmer, Raymond J. (Inventor); Moore, William E. (Inventor)

    1994-01-01

    Process for vacuum impregnation of a dry fiber reinforcement with a curable resin to produce a resin-fiber composite, by drawing a vacuum to permit flow of curable liquid resin into and through a fiber reinforcement to impregnate same and curing the resin-impregnated fiber reinforcement at a sufficient temperature and pressure to effect final curing. Both vacuum and positive pressure, e.g. autoclave pressure, are applied to the dry fiber reinforcement prior to application of heat and prior to any resin flow to compact the dry fiber reinforcement, and produce a resin-fiber composite of reduced weight, thickness and resin content, and improved mechanical properties. Preferably both a vacuum and positive pressure, e.g. autoclave pressure, are also applied during final curing.

  17. Study on thermal conductive BN/novolac resin composites

    International Nuclear Information System (INIS)

    Li, Shasha; Qi, Shuhua; Liu, Nailiang; Cao, Peng

    2011-01-01

    Highlights: → Boron nitride (BN) particles were used to modify novolac resin. → BN particles were pretreated by γ-aminopropyltriethoxysilane. → The thermal conductivity trend of composite almost agrees with the predicted data from the Maxwell-Eucken model. → At BN concentration of 80 wt.%, thermal conductivity value of composite is 4.5 times that of pure novolac resin. → Combined use of the larger and smaller particles with a mass ratio of 1:2 provides the composites with the maximum thermal conductivity among the testing systems. → The composite thermal property also increases with an increase in the BN concentration. - Abstract: In this study, γ-aminopropyltriethoxysilane-treated boron nitride (BN) particles were used to modify novolac resin. The effect of varying the BN concentration, particle size, and hybrid BN fillers with the binary particle size distribution on the thermal conductivity of the composites was investigated. Scanning electron microscopy (SEM) imaging showed homogeneously dispersed treated BN particles in the matrix. Furthermore, the thermal conductivity increased as the BN concentration was increased. This behavior was also observed when the filler size was increased. Experimentally obtained thermal conductivity values agree with the predicted data from the Maxwell-Eucken model well at less than 70 wt.% BN loading. A larger particle size BN-filled novolac resin exhibits a higher thermal conductivity than a smaller particle size BN-filled one. The combined use of 0.5 and 15 μm particles with a mass ratio of 2:1 achieved the maximum thermal conductivity among the testing systems. The thermal resistance properties of the composites were also studied.

  18. Evaluation of ion exchange resins for iron control in copper electro-winning solutions; Evaluacion de resinas de intercambio ionico para el control de hierro en soluciones de electro-obtencion de cobre

    Energy Technology Data Exchange (ETDEWEB)

    Parada, F.; Dreisinger, D.; Wilkomirsky, I.

    2010-07-01

    Two commercial resins were evaluated for the extraction of iron from a copper electrowinning solution. Both resins efficiently extract iron. The Mono phosphonic resin has a greater charge capacity than the Diphonix resin and the Diphonix resin shows faster kinetics. Experimental results of the interrupted test and tests with different particle size of resins have demonstrated that extraction kinetics is controlled by diffusion into the particle in both resins. A good agreement with Fick's model for diffusion inside the particles confirms the proposed mechanism. Finally, temperature favors the process kinetics and its effect on the diffusion coefficient follows Arrhenius law, obtaining a value of 4,89 kcal/mol for the Mono phosphonic resin and 4,94 kcal/mol for the Diphenox resin. The aforementioned values are close to typical values for the proposed diffusional control which are 6 to 10 kcal/mol. (Author)

  19. Identification of metals into fine particles (PM{sub 2.5}) during the dry cold season in the Toluca City; Identificacion de metales en particulas finas (PM{sub 2.5}) durante la epoca seca-fria en la ciudad de Toluca

    Energy Technology Data Exchange (ETDEWEB)

    Martinez P, A. A. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Tollocan esquina Paseo Colon s/n, Toluca 50180, Estado de Mexico (Mexico); Aldape U, F. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2008-07-01

    To know the elemental content of fine particles PM{sub 2.5} that can affect people in the Toluca City, such as metals and another, it was made a campaign collection of fine particles during dry-cold ( November 2006-March 2007). The aerosol samples were collected on Teflon filters with an equipment BGI model PQ200 mark authorized by the Environment Protection Agency (EPA), every other day with a time resolution of 24 h. The determination of the elemental composition of the samples was performed by means of the technique Particle Induced X-Ray Emission (PIXE). The results of the analysis showed consistently 13 elements S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, as, throughout the collection period. We calculated the enrich factor that separates the elements of the natural component of the anthropogenic component. The correlation matrix shows the pairs of elements that are contained in the same air mass as Vanadium and Nickel. From the results it is concluded that the sources that gave rise to these particles are the burning of fossil fuels in motor vehicles, lubricants, additives and burning tires wear of automotive vehicles, besides the products used in agricultural activities. (Author)

  20. Dispersibility of lactose fines as compared to API in dry powders for inhalation.

    Science.gov (United States)

    Thalberg, Kyrre; Åslund, Simon; Skogevall, Marcus; Andersson, Patrik

    2016-05-17

    This work investigates the dispersion performance of fine lactose particles as function of processing time, and compares it to the API, using Beclomethasone Dipropionate (BDP) as model API. The total load of fine particles is kept constant in the formulations while the proportions of API and lactose fines are varied. Fine particle assessment demonstrates that the lactose fines have higher dispersibility than the API. For standard formulations, processing time has a limited effect on the Fine Particle Fraction (FPF). For formulations containing magnesium stearate (MgSt), FPF of BDP is heavily influenced by processing time, with an initial increase, followed by a decrease at longer mixing times. An equation modeling the observed behavior is presented. Surprisingly, the dispersibility of the lactose fines present in the same formulation remains unaffected by mixing time. Magnesium analysis demonstrates that MgSt is transferred to the fine particles during the mixing process, thus lubrication both BDP and lactose fines, which leads to an increased FPF. Dry particle sizing of the formulations reveals a loss of fine particles at longer mixing times. Incorporation of fine particles into the carrier surfaces is believed to be behind this, and is hence a mechanism of importance as regards the dispersion performance of dry powders for inhalation. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. New methods and standards for fine dust

    International Nuclear Information System (INIS)

    Spielvogel, Juergen; Hartstock, Stefan; Grimm, Hans

    2009-01-01

    There seems to be common agreement that PM10 is a suboptimal quantity for the quantification of potential dangers from fine dust due to a number of reasons, notably because the chemical composition of the particles is not considered, because the size distribution is disregarded, and because of sampling artefacts. In a first step for improving the particle measurements, the European Community has published new directives for ambient air in June 2008 (EU 2008), which as a main part included new regulations for PM2.5 measurements, in addition to the further on valid regulations for PM10. The comparison of PM2.5 and PM10 may allow a source apportionment and a better assessment of the influence of fine dust on human health. The source apportionment may allow more effective fine dust reduction strategies.

  2. Observations of substorm fine structure

    Directory of Open Access Journals (Sweden)

    L. L. Lazutin

    1998-07-01

    Full Text Available Particle and magnetic field measurements on the CRRES satellite were used, together with geosynchronous satellites and ground-based observations, to investigate the fine structure of a magnetospheric substorm on February 9, 1991. Using the variations in the electron fluxes, the substorm activity was divided into several intensifications lasting about 3–15 minutes each. The two main features of the data were: (1 the intensifications showed internal fine structure in the time scale of about 2 minutes or less. We call these shorter periods activations. Energetic electrons and protons at the closest geosynchronous spacecraft (1990 095 were found to have comparable activation structure. (2 The energetic (>69 keV proton injections were delayed with respect to electron injections, and actually coincided in time with the end of the intensifications and partial returns to locally more stretched field line configuration. We propose that the energetic protons could be able to control the dynamics of the system locally be quenching the ongoing intensification and possibly preparing the final large-scale poleward movement of the activity. It was also shown that these protons originated from the same intensification as the preceeding electrons. Therefore, the substorm instability responsible for the intensifications could introduce a negative feedback loop into the system, creating the observed fine structure with the intensification time scales.Key words. Magnetospheric Physics (Storms and substorms.

  3. PRODUCTION OF HIGH DENSITY PARTICLEBOARD USING MELAMINE-UREA-FORMALDEHYDE RESIN

    Directory of Open Access Journals (Sweden)

    Setsuo Iwakiri

    2005-12-01

    Full Text Available This research was developed aiming to evaluate the effects of board density and melamine-urea-formaldehyde resin onthe properties of particleboard for semi-structural applications. The boards were manufactured with nominal density of 0.65 g/cm³and 0.90 g/cm³ using urea-formaldehyde resin as control and melamine-urea-formaldehyde. The results showed a better dimensionallystability and mechanical properties of the boards manufactured with higher density and MUF resin content. The fine furnish usedfor external layer of particleboard in the industrial process, could be used for high density homogeneous board to semi-strucuturaluses, such as flooring applications.

  4. Urea-formaldehyde resins: production, application, and testing

    Science.gov (United States)

    Nuryawan, A.; Risnasari, I.; Sucipto, T.; Heri Iswanto, A.; Rosmala Dewi, R.

    2017-07-01

    Urea-formaldehyde (UF) resin, one of the most important formaldehyde resin adhesives, is a polymeric condensation product of formaldehyde with urea, and being widely used for the manufacture of wood-based composite panels, such as plywood, particleboard, and fiberboard. In spite of its benefits such as fast curing, good performance in the panels (colorless), and lower cost; formaldehyde emission (FE) originated from either UF resin itself or composite products bonded by UF resins is considered a critical drawback as it affects human health particularly in indoor environment. In order to reduce the FE, lowering formaldehyde/urea (F/U) mole ratio in the synthesis of the UF resin was done. In this study, synthesis of UF resins was carried out following the conventional alkaline-acid two-step reaction with a second addition of urea, resulting in F/U mole ratio around 1.0, namely 0.95; 1.05, and 1.15. The UF resins produced were used as binder for particleboard making. The board was manufactured in the laboratory using shaving type particle of Gmelina wood, 8% UF resin based on oven dry particle, and 1% NH4Cl (20%wt) as hardener for the resin. The target of the thickness was 10 mm and the dimension was 25 cm x 25 cm. The resulted particleboard then was evaluated the physical and the mechanical properties by Japanese Industrial Standard (JIS) A 5908 (2003). Further, the resulted particleboard also was used for the mice cage’s wall in order to mimic the real living environment. After four weeks exposure in the cages, the mice then were evaluated their mucous organs as well as their blood. The experiment results were as follows: 1) It was possible to synthesis UF resins with low F/U mole ratio; 2) However, the particleboard bonded UF resins with low F/U mole ratio showed poor properties, particularly on the thickness swelling and modulus of elasticity; 3) There was no significant differences among the mucous organs of the mice after a month exposure FE originated from

  5. Frictional and heat resistance characteristics of coconut husk particle filled automotive brake pad

    Science.gov (United States)

    Bahari, Shahril Anuar; Chik, Mohd Syahrizul; Kassim, Masitah Abu; Som Said, Che Mohamad; Misnon, Mohd Iqbal; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    The objective of this study was to determine the friction and heat resistance characteristics of automotive brake pad composed with different sizes and percentages of coconut husk particle. The materials used were phenolic resin (phenol formaldehyde) as binder, copper, graphite and brass as friction producer/modifiers, magnesium oxide as abrasive material, steel and barium sulfate as reinforcement while coconut husk particle as filler. To obtain particle, the coconut husk was ground and dried to 3% moisture content. Then the coconut husk particle was screened using 80 mesh (to obtain coarse dust) and 100 mesh (to obtain fine dust). Different percentages of particle, such as 10 and 30% were used in the mixture of brake pad materials. Then the mixture was hot-pressed to produce brake pad. Chase machine was used to determine the friction coefficient in friction resistance testing, while thermogravimetric analyzer (TGA) machine was used to determine the heat decomposition values in heat resistance testing. Results showed that brake pad with 100 mesh and 10% composition of coconut husk particle showed the highest friction coefficient. For heat resistance, brake pad with 100 mesh and 30% composition of coconut husk dust showed the highest decomposition temperature, due to the high percentage of coconut husk particle in the composition, thus increased the thermal stability. As a comparison, brake pad composed with coconut husk particle showed better heat resistance results than commercial brake pad.

  6. The Fine Structure Constant

    Indian Academy of Sciences (India)

    IAS Admin

    The article discusses the importance of the fine structure constant in quantum mechanics, along with the brief history of how it emerged. Al- though Sommerfelds idea of elliptical orbits has been replaced by wave mechanics, the fine struc- ture constant he introduced has remained as an important parameter in the field of ...

  7. Shear bond strength of the amalgam-resin composite interface.

    Science.gov (United States)

    Machado, Camilo; Sanchez, Eliana; Alapati, Satish; Seghi, Robert; Johnston, William

    2007-01-01

    This study compared the initial and one year shear bond strengths (SBS) of resin composite bonded to amalgam using Amalgambond-Plus. Resin composite cylinders (Point 4, Kerr Corporation) were bonded to either etched-enamel (A), 50% etched enamel-50% polished amalgam (B), airborne-particle abraded amalgam (C), carbide bur prepared amalgam (D) and airborne-particle abraded 50% amalgam-50% etched-enamel (E). Shear bond strengths were determined using a standardized testing device (Ultradent Products) in a universal testing machine (Instron model 4204). The failed interfaces were evaluated with SEM to obtain visual evidence of the failure mode. ANOVA indicated significant differences among the groups (p composite masking has the strongest, most durable SBS on airborne-particle abraded amalgam and airborne-particle abraded enamel-amalgam surfaces and could be used as a method to improve the esthetics of amalgam restorations.

  8. Electrodeposition properties of modified cational epoxy resin-type photoresist

    International Nuclear Information System (INIS)

    Yong He; Yunlong Zhang; Feipeng Wu; Miaozhen Li; Erjian Wang

    1999-01-01

    Multi-component cationic epoxy and acrylic resin system for ED photoresist was used in this work, since they can provide better storage stability for ED emulsion and better physical and chemical properties of deposited film than one-component system. The cationic main resin (AE) was prepared from amine modified epoxy resins and then treated with acetic acid. The amination degree was controlled as required. The synthetic procedure of cationic main resins is described in scheme I. The ED photoresist (AME) is composed of cationic main resin (AE) and nonionic multifunctional acrylic crosslinkers (PETA), in combination with suitable photo-initiator. They can easily be dispersed in deionized water to form a stable ED emulsion. The exposed part of deposited film upon UV irradiation occurs crosslinking to produce an insoluble semi-penetrating network and the unexposed part remains good solubility in the acidic water solution. It is readily utilized for fabrication of fine micropattern. The electrodeposition are carried out on Cu plate at room temperature. To evaluate the electrodeposition properties of ED photoresist (AME), the different influences are examined

  9. Modification of unsaturated polyester resins using nano-size core ...

    African Journals Online (AJOL)

    Modification of unsaturated polyester resins using nano-size core-shell particles. MO Munyati, PA Lovell. Abstract. No Abstract Available Journal of Science and Technology Special Edition 2004: 24-31. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  10. Emulsification of resin modified by simultaneous graft polymerization with electron beam

    International Nuclear Information System (INIS)

    Hosoi, Fumio; Sasaki, Takashi; Hagiwara, Miyuki

    1983-01-01

    Emulsification of the epoxy resins, onto which hydrophilic groups were introduced by simultaneous co-graft polymerization with electron beam irradiation, were studied. Resins modified with use of ionic monomers such as methacrylic acid (MAc), diethylaminoethyl methacrylate (DE), tetramethylammonium methacrylate (TMAMA), or methacryloyloxyethyltrimethyl ammonium chloride (QDM) formed latexes, when they were dissolved into small amounts of solvents followed by the addition of water. A higher composition of hydrophilic monomer in the resin-monomer mixture gave a latex with a smaller particle size and higher storage stability. TMAMA and QDM, both of which were incompatible with epoxy resin, were very effective in decreasing the particle size and increasing stability of a latex. It was also ascertained that an alkyd resin were able to emulsified similarly by grafting of 2-hydroxyethyl methacrylate and MAc. (author)

  11. Flame Retardant Epoxy Resins

    Science.gov (United States)

    Thompson, C. M.; Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.; Lyon, R. E.

    2004-01-01

    As part of a program to develop fire resistant exterior composite structures for future subsonic commercial aircraft, flame retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured epoxies were characterized by thermogravimetric analysis, propane torch test, elemental analysis and microscale combustion calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness of plaques of several cured formulations was determined on single-edge notched bend specimens. The chemistry and properties of these new epoxy formulations are discussed.

  12. Thermal and mechanical behaviour of sub micron sized fly ash reinforced polyester resin composite

    Science.gov (United States)

    Nantha Kumar, P.; Rajadurai, A.; Muthuramalingam, T.

    2018-04-01

    The utilization of particles reinforced resin matrix composites is being increased owing to its lower density and high strength to weight ratio. In the present study, an attempt has been made to synthesize fly ash particles reinforced polyester resin composite for engine cowling application. The thermal stability and mechanical behaviours such as hardness and flexural strength of the composite with 2, 3 and 4 weight % of reinforcement is studied and analyzed. The thermo gravimetric analysis indicates that the higher addition of reinforcement increases the decomposition temperature due to its refractory nature. It is also observed that the hardness increases with higher filler addition owing to the resistance of FA particles towards penetration. The flexural strength is found to increase up to the addition of 3% of FA particles, whereas the polyester resin composite prepared with 4% FA particles addition is observed to have low flexural strength owing to agglomeration of particles.

  13. Bismaleimide Copolymer Matrix Resins

    Science.gov (United States)

    Parker, John A.; Heimbuch, Alvin H.; Hsu, Ming-Ta S.; Chen, Timothy S.

    1987-01-01

    Graphite composites, prepared from 1:1 copolymer of two new bismaleimides based on N,N'-m-phenylene-bis(m-amino-benzamide) structure have mechanical properties superior to those prepared from other bismaleimide-type resins. New heat-resistant composites replace metal in some structural applications. Monomers used to form copolymers with superior mechanical properties prepared by reaction of MMAB with maleic or citraconic anhydride.

  14. Penentuan Supplier Resin Dengan Menggunakan Analytical Network Process

    Directory of Open Access Journals (Sweden)

    Septian Ricky Adi Pratama

    2015-04-01

    Full Text Available Pengambilan keputusan multikriteria adalah proses pemilihan suatu alternatif terbaik dari beberapa allternatif yang ada berdasarkan sejumlah kriteria dari suatu permasalahan. Pemilihan supplier yang terjadi pada PT. KTI divisi particle board selama ini hanya bersifat objektif, sehingga terjadi berbagai permasalahan didalam produksi yang disebabkan kualitas bahan baku (resin tidak sesuai dengan standar yang ditetapkan perusahaan. Selain itu terjadi keterlambatan pengiriman, hal ini berpengaruh terhadap umur resin (live time resin dimana kualitas resin juga akan menurun. Masalah yang lain ialah mengenai respon atau tanggapan dari supplier terhadap keluhan-keluhan perusahaan. Setiap supplier resin memiliki kekurangan dan kelebihan dalam setiap kriterianya, ada 4 kriteria yang harus dipenuhi setiap supplier resin yaitu kualitas (Quality, pengiriman (Delivery, respon (Responsiveness dan harga (Cost. Penelitian ini memodelkan hubungan saling mempengaruhi dan dependency antar kriteria dan alternatif supplier, menerjemahkan preferensi pengambilan keputusan dalam bentuk skala numeric dan mensintensis hasil berupa prioritas alternatif supplier. Metode ANP digunakan untuk memodelkan hubungan tersebut dan mendapatkan prioritas dari penilaian pengambil keputusan dengan pembentukkan super matriks. Super matriks didapatkan dari perbandingan berpasangan elemen yang dipengaruhi terhadap elemen yang mempengaruhinya. Hasil yang diperoleh adalah bobot prioritas global untuk alternatif supplier yang menunjukkan urutan terpilihnya. Suppiler PT PAI menduduki peringkat pertama, diikuti supplier PT. DOVER, dan urutan ketiga  PT. ARUKI dan urutan keempat AICA.

  15. Paramagnetic epoxy resin

    Directory of Open Access Journals (Sweden)

    E. C. Vazquez Barreiro

    2017-01-01

    Full Text Available This work illustrates that macrocycles can be used as crosslinking agents for curing epoxy resins, provided that they have appropriate organic functionalities. As macrocycles can complex metal ions in their structure, this curing reaction allows for the introduction of that metal ion into the resin network. As a result, some characteristic physical properties of the metallomacrocycle could be transferred to the new material. The bisphenol A diglycidyl ether (BADGE, n = 0 and hemin (a protoporphyrin IX containing the Fe(III ion, and an additional chloride ligand have been chosen. The new material has been characterized by differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, Fourier Transform Infrared (FT-IR, Nuclear Magnetic Resonance (NMR, Transmission Electron Microscopy (TEM, and magnetic susceptibility measurements. Fe(III remains in the high-spin state during the curing process and, consequently, the final material exhibits the magnetic characteristics of hemin. The loss of the chlorine atom ligand during the cure of the resin allows that Fe(III can act as Lewis acid, catalyzing the crosslinking reactions. At high BADGE n = 0/hemin ratios, the formation of ether and ester bonds occurs simultaneously during the process.

  16. Agglomeration of coal fines for premium fuel application

    International Nuclear Information System (INIS)

    Atalay, A.; Zaman, M.D.

    1992-01-01

    This paper reports on fine coal in liquid suspension, which can be agglomerated in a number of ways. One of the oldest procedures involves the addition of electrolyte to the suspension to cause a reduction in the zeta potential and allow colliding particles to agglomerate. A second method involves the use of polymeric flocculants to bridge between particles. Both of these technologies are being used in the wastewater treatment plants for removal of fine waste particles from contaminated water. A third method involves the addition of a second immiscible liquid preferentially to wet the particles and cause adhesion by capillary interfacial forces. While the bonding forces in the first two methods are small and result in rather weak and voluminous agglomerates, the third method is postulated to produce more dense and much stronger agglomerates. In the case of fine coals, the carbonaceous constituents can be agglomerated and recovered from the aqueous suspension with many different coagulants. Inorganic or ash-forming constituents are also agglomerated along with the fine coal particles. As the froth floatation, agglomeration using coal and colloidal dust to effect a separation. Froth floatation, however, becomes less effective where extremely fine particles of cal must be treated or if there is considerable clay-size particle present. In contrast, there appears to be virtually no lower limit on the particle size suitable for agglomeration uses

  17. New Carbon Source From Microbial Degradation of Pre-Production Resin Pellets from the North Pacific Gyre

    Science.gov (United States)

    Neal, A.; Mielke, R.; Stam, C. N.; Gonsior, M.; Tsapin, A. I.; Lee, G.; Leftwich, B.; Narayan, R.; Coleman, H.; Argyropoulos, N.; Sheavly, S. B.; Gorby, Y. A.

    2011-12-01

    Numerous pollutants are transported through the world's oceans that impact oceanic health. Diffuse sources include land-based runoff, atmospheric depositions, shipping industry wastes, and others. Synthetic polymer marine debris is a multi-faceted problem that includes interactions with environmental toxins, carbon cycling systems, ocean surface chemistry, fine minerals deposition, and nano-particles. The impact that synthetic polymer-microbe interactions have on carbon input into the open ocean is poorly understood. Here we demonstrate that both biotic and abiotic processes contribute to degradation of pre-production resin pellets (PRPs), in open ocean environments and new methodologies to determine carbon loss from this synthetic polymer debris. Our data shows that material degradation of environmental polyethylene PRPs can potentially deposit 13 mg/g to 65 mg/g of carbon per PRP into our marine environments. Environmental pre-production resin pellets were collected on the S/V Kaisei cruise in 2009 which covered over 3,000 nautical miles and sampled over 102,000 m3 of the first 15cm of the water column in the Subtropical Convergence Zone of the North Pacific Gyre. Environmental PRP degradation and the role microbial communities play in this was evaluated using a combination of Fourier transform infrared spectroscopy, environmental scanning electron microscopy, scanning transmission electron microscopy, X-ray microtomography, and ArcGIS mapping. More research is needed to understand the environmental impact of this new carbon source arising from synthetic polymers as they degrade in oceanic environments.

  18. 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 ca. 5-20% of the soil, were recognized and petrologically classified. The coarsest sizes of the regolith are chemically and mineralogically similar, while the finest fractions are more feldspathic, probably due to easier fracturing of plagioclase than mafic minerals. Due to the more feldspathic nature of the very fine lunar soils, in this paper, we quantitatively investigate the influence of very fine (1250 nm band depth, close to zero; (3) consequently, the plagioclase band is always shallower than mafic bands; (4) in mixtures with olivine, the composite band center always shows the typical olivine value, differently from coarser mixtures; and (5) mafic materials have a blue slope in the Short Wavelength Infrared Region, a more V-shaped 1 μm pyroxene absorption and the 1 μm mafic band centers are shifted by ca. 40 nm vs. coarse sizes, reflecting a different weight within the crystal field absorption of the mafic component in very fine size. We also evidenced that a coarse plagioclase could be overestimated, while a very fine one could be underestimated if compared with the 63-125 μm size.

  19. Biokompatibilitas Gelas Ionomer Modifikasi Resin

    OpenAIRE

    Rotua Lestari M

    2008-01-01

    Saat ini banyak berkembang material baru dalam dunia kedokteran gigi diantaranya adalah Gelas ionomer modifikasi resin yang dikembangkan untuk mengatasi kekurangan-kekurangan dari gelas ionomer konvensional. Adanya penambahan monomer resin daIam bentuk 2-hydroxyethylmetacylate (HEMA) telah meningkatkan kekuatan dari bahan ini. Gelas ionomer modifikasi resin mempunyai sifat-sifat fisis dan mekanis yang lebih baik dibandingkan dengan gelas ionomer konvensional. Gelas ionomer modifikasi ...

  20. Handling sticky Resin by Stingless Bees: Adhesive Properties of Surface Structures

    Directory of Open Access Journals (Sweden)

    MARKUS GASTAUER

    2013-09-01

    Full Text Available Many Stingless Bees (Hymenoptera: Meliponini like Tetragonisca angustula collect resin to defend their nests against intruders like ants or Robber Bees. Small portions of resin are attached to intruders bodies and extremities causing their immobilization. It has been observed that resin is removed easily from the bee's mandible but adheres strongly to the intruder's cuticle. We tested the hypothesis that resin sticks lesser to the mandibles of Stingless Bees than to the surface of intruders due to special surface structures or adhesive properties of these structures. The surface structures of the mandible of T. angustula and the trochanter of Camponotus sericeiventris were studied by scanning electron microscopy. To measure adhesion properties, selected surfaces were fixed on a fine glass pin and withdrawn from a glass tip covered with resin. The deformation of the glass pin indicates adhesion forces operating between the resin and the selective surface. The absolute value of the forces is computed from the glass pin's stiffness. It has been shown that resin sticks more to the smooth mandible of the bee than to the structured trochanter of the ant. A new hypothesis to be tested says that the bees might lubricate their mandibles with nectar or honey to reduce the resin's adhesion temporarily.

  1. Integrating Porous Resins In Enzymatic Processes

    DEFF Research Database (Denmark)

    Al-Haque, Naweed

    of these enzymes to be harnessed. Porous resins as opposed to other auxiliary phases, for example organic solvents, are nonbioavailable, biocompatible and offer simpler operational handling (no foaming and emulsification). This strategy has been applied effectively to single substrate – single product systems...... concentration in the reactor and thus not aid in alleviating inhibition. Further considerationsProcess modelling is a very effective tool in evaluating a process. Critical information about the process can be gained by means of simulations, which can further be re-used to tune the reaction or process conditions...... properties and potential ‘green’ attributes, presents it as a sustainable alternative. Today, the role of biocatalysis is most evident in the pharmaceutical industry and is currently extending towards fine and bulk chemical production as well. The use of hydrolytic enzymes (lipases) is well established...

  2. Fine Arts Database (FAD)

    Data.gov (United States)

    General Services Administration — The Fine Arts Database records information on federally owned art in the control of the GSA; this includes the location, current condition and information on artists.

  3. Analyses of fine paste ceramics

    International Nuclear Information System (INIS)

    Sabloff, J.A.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics

  4. Analyses of fine paste ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sabloff, J A [ed.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  5. Increasing the mechanical strength of fine-grained concrete by introducing finely dispersed mineral additives

    Science.gov (United States)

    Khakimullina, Svetlana; Il'ina, Liliia; Mukhina, Irina

    2017-01-01

    The paper investigates the influence of particles size and the quantity of mineral additives, both active and inert, on the strength of fine-grained concrete. Concentrations of fine silica fume and diopside for maximum hardening of fine-grained concrete with a given size of input particles were determined experimentally. The strength properties of fine-grained concrete were detected by testing the sample beams with dimensions of 40×40×160 mm after 28 days of hardening under normal conditions. The results show that adding silica fume in the amount of 12% increases the compressive strength of concrete up to 55%; 7% of diopside with 52.5 microns dispersion - up to 46.7%; 3% of diopside with 8.9 microns dispersion - up to 45.8%. It was found that the greater the dispersion of inert mineral additive is, the less its optimum amount providing maximum hardening of fine-grained concrete is. Thus, the optimum ratio of these two mineral additives was determined to achieve the required strength. Adding 12% of silica fume and 7% of diopside with 52.5 microns dispersion provides the highest efficiency of the concrete strength properties. The fine concrete with such relation of additives has the strength 2.5 times greater compared to the control one.

  6. Controlled release of chlorhexidine from a HEMA-UDMA resin using a magnetic field.

    Science.gov (United States)

    Luo, Dong; Shahid, Saroash; Hasan, Samiul Md; Whiley, Robert; Sukhorukov, Gleb B; Cattell, Michael J

    2018-02-26

    To functionalize novel chlorhexidine (CHX) particles with iron oxide (Fe 3 O 4 ) nanoparticles and control their release kinetics in a dental resin using an external magnetic field. Fe 3 O 4 nanoparticles were synthesized and incorporated into spherical CHX particles and the powder was freeze dried. Resin disc specimens were produced using a UDMA-HEMA resin mixed with freeze dried spherical Fe 3 O 4 -CHX particles (5wt.%), which were placed into a Teflon mould (10mm diameter×1mm depth) and covered with a Mylar strip. A MACS magnet was left in contact for 0min (Group 1), 5min (Group 2) or 10min (Group 3) and the resin discs subsequently light cured (Bluedent LED pen, Bulgaria) for 60s per side. The resin discs were immersed in deionized water at various time points up to 650h. UV-Vis absorbance was used to determine the CHX content. CHX released for each time point was determined. The functionalized CHX particles and resin discs were characterized using TEM, TGA, EDX and SEM. Fe 3 O 4 nanoparticles (20nm) incorporated into the spherical CHX particles led to a mean (SD) particle size reduction from 17.15 (1.99)μm to 10.39 (2.61)μm. The presence of Fe 3 O 4 nanoparticles in the spherical CHX particles was confirmed with SEM, EDX, and TGA. SEM of Group 1 resin discs (no magnetic exposure) showed functionalized CHX spheres were homogeneously distributed within the resin discs. For resin discs which had magnetic exposure (5 or 10min) the particles started to cluster nearer the surface (Group 2: 43.7%, Group 3: 57.3%), to a depth of 94μm. UV-Vis absorbance reveal