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Sample records for epoxy-based particulate composites

  1. Shock Equation of State of Single Constituent and Multi-Constituent Epoxy-Based Particulate Composites

    DTIC Science & Technology

    2010-10-01

    There are several studies in the literature regarding the equation of state of alumina-epoxy composites. Although this single component system...paper presents a review of shock loading studies on epoxy-based particulate composites. The relationship between equation of state parameters and

  2. High Strain Rate Mechanical Properties of Epoxy and Epoxy-Based Particulate Composites (Preprint)

    DTIC Science & Technology

    2007-05-01

    stainless steel or 6061 -T6 aluminum. The striker is 305 mm long and made of the same material as the other bars. The samples, which were nominally 8 mm...Property Correlation in Discontinuously-Reinforced Aluminium Matrix Composites as a Function of Relative Particle Size Ratio. Mat. Sci. Eng., 2002. A337: p

  3. High Strain Rate Mechanical Properties of Epoxy and Epoxy-Based Particulate Composites

    DTIC Science & Technology

    2007-08-01

    steel or 6061 -T6 aluminum. The striker is 305 mm long and made of the same material as the other bars. The samples, which were nominally 8 mm...Correlation in Discontinuously-Reinforced Aluminium Matrix Composites as a Function of Relative Particle Size Ratio. Mat. Sci. Eng., 2002. A337: p

  4. Electrical resistivity and piezoresistivity of Ni-CNT filled epoxy-based composites

    NASA Astrophysics Data System (ADS)

    Jiang, Jinbao; Xiao, Huigang; Li, Hui

    2013-04-01

    This paper investigates properties about electrical resistivity and piezoresistivity of multi-wall carbon nanotubes (MWCNTs)-filled epoxy-based composite and its further use for strain sensing. The MWCNTs dispersed epoxy resin, using MWCNTs in the amount of 1.5~3.0 vol.%, was first prepared by combined high-speed stirring and sonication methods. Then, the MWCNTs dispersed epoxy resin was cast into an aluminum mold to form specimens measuring 10×10×36 mm. After curing, DC electrical resistance measurements were performed along the longitudinal axis using the four-probe method, in which copper nets served as electrical contacts. The percolation threshold zone of resistivity was got as MWCNTs in the amount of 2.00-2.50 vol.%. Further compressive testing of these specimens was conducted with four-probe method for resistance measurements at the same time. Testing results show that the electrical resistivity of the composites changes with the strain's development, namely piezoresistivity. While for practical strain sensing use, signals of electric resistance and current in the acquisition circuits were both studied. Results show that the signal of current, compared with that of resistance, had better linear relationship with the compressive strain, better stability and longer effective section to reflect the whole deformation process of the specimens under pressure. Further works about the effects of low magnetic field on the electrical resistivity and piezoresistivity of Ni-CNTs filled epoxy-based composites were presented briefly at the end of the paper.

  5. Calibration of an analytical thermal model for an epoxy-based composite sandwich design

    NASA Astrophysics Data System (ADS)

    Reinarts, Thomas R.; Davis, Darrell; Stuckey, Charles I.

    2001-02-01

    An epoxy-based sandwich configuration was designed to meet the structural and thermal requirements of a nose cap for the space shuttle solid rocket boosters (SRB's). This project was suspended in late 1999, but the information gathered during this work is unique in the sense that portions of graphite-epoxy layers were modeled at temperatures exceeding their glass transition temperatures. This work presents the results of the thermal model calibration efforts. A symmetric sandwich configuration was chosen that includes an inner and outer structural skin with a graphite-epoxy composite, Hexcel's AGP370-8H/3501-6 (AS4/3501-6), and a center epoxy-based syntactic core. 3M SC350G, that provides thermal protection. Each graphite-epoxy section consists of seven layers, each layer with a 0°, 90°, or +/-45° graphite fiber orientation. Three flat panels (0.305×0.483 m top view dimensions) using this sandwich construction were fabricated and exposed to an aerothermal environment in the Marshall Space Flight Center (MSFC) Improved Hot Gas Facility (IHGF). Each of these panels had ten interstitial thermocouples in the panel. The exact locations of the thermocouples and thickness of the different layers were determined by X-ray evaluation. A 1-D model was generated that used the outer surface IR measured temperature as a boundary condition, and the predicted temperatures were compared with the measured temperatures, calibrating the code. .

  6. Mechanics of particulate composites with glassy polymer binders in compression

    PubMed Central

    Jordan, J. L.; Spowart, J. E.; Kendall, M. J.; Woodworth, B.; Siviour, C. R.

    2014-01-01

    Whether used as structural components in design or matrix materials for composites, the mechanical properties of polymers are increasingly important. The compressive response of extruded polymethyl methacrylate (PMMA) rod with aligned polymer chains and Al–Ni–PMMA particulate composites are investigated across a range of strain rates and temperatures. The particulate composites were prepared using an injection-moulding technique resulting in highly anisotropic microstructures. The mechanics of these materials are discussed in the light of theories of deformation for glassy polymers. The experimental data from this study are compared with PMMA results from the literature as well as epoxy-based composites with identical particulates. The PMMA exhibited the expected strain rate and temperature dependence and brittle failure was observed at the highest strain rates and lowest temperatures. The Al–Ni–PMMA composites were found to have similar stress–strain response to the PMMA with reduced strain softening after yield. Increasing volume fraction of particulates in the composite resulted in decreased strength. PMID:24711495

  7. Effectively Exerting the Reinforcement of Dopamine Reduced Graphene Oxide on Epoxy-Based Composites via Strengthened Interfacial Bonding.

    PubMed

    Li, Wenbin; Shang, Tinghua; Yang, Wengang; Yang, Huichuan; Lin, Song; Jia, Xiaolong; Cai, Qing; Yang, Xiaoping

    2016-05-25

    The effects of dopamine reduced graphene oxide (pDop-rGO) on the curing activity and mechanical properties of epoxy-based composites were evaluated. Taking advantage of self-polymerization of mussel-inspired dopamine, pDop-rGO was prepared through simultaneous functionalization and reduction of graphene oxide (GO) via polydopamine coating. Benefiting from the universal binding ability of polydopamine, good dispersion of pDop-rGO in epoxy matrix was able to be achieved as the content of pDop-rGO being below 0.2 wt %. Curing kinetics of epoxy composites with pDop-rGO were systematically studied by nonisothermal differential scanning calorimetry (DSC). Compared to the systems of neat epoxy or epoxy composites containing GO, epoxy composites loaded with pDop-rGO showed lower activation energy (Eα) over the range of cure (α). It revealed that the amino-bearing pDop-rGO was able to react with epoxy matrix and enhance the curing reactions as an amine-type curing agent. The nature of the interactions at GO-epoxy interface was further evaluated by Raman spectroscopy, confirming the occurrence of chemical bonding. The strengthened interfacial adhesion between pDop-rGO and epoxy matrix thus enhanced the effective stress transfer in the composites. Accordingly, the tensile and flexural properties of EP/pDop-rGO composites were enhanced due to both the well dispersion and strong interfacial bonding of pDop-rGO in epoxy matrix.

  8. Morphological and electrical properties of epoxy-based composites reinforced with exfoliated graphite

    NASA Astrophysics Data System (ADS)

    Lamberti, Patrizia; Spinelli, Giovanni; Tucci, Vincenzo; Guadagno, Liberata; Raimondo, Marialuigia; Vertuccio, Luigi

    2016-05-01

    An experimental study has been carried out to prepare and characterize epoxy/amine-based composites filled with different percentages of partially exfoliated graphite (i.e. pEG) particles having an exfoliation degree of 56% in order to analyze the effect of the filler amounts on the electrical properties of the resulting nanocomposites. Moreover, in order to fully investigate the direct relationship between the physical properties of the employed filler and the results of the electrical characterization, a structural and morphological characterization of the pEG samples is carried out by means of various type of analysis such as X-ray diffraction patterns, micro-Raman and Scanning Electron Microscopy (SEM) images. The DC electrical characterization reveals a percolation thresholds (EPT) that falls in the range [2-3] wt% and an electrical conductivity of about 0.66 S/m at the highest filler loading (6.5 wt%). From the analysis of the percolative curve it is possible to derive the percolation law parameters and in particular the critical exponent t, whose value (i.e. 1.2) reflects an effective 2D organization of the percolating structure consistent with the type of filler used (2-dimensional). Finally, an extensive analysis concerning the electrical properties in the frequency domain has been carried out in order to evaluate the effectiveness of pEG-loaded composites in terms of electromagnetic interference compatibility (EMC) and their applicability as radar absorbers materials (RAMs).

  9. Shock Equation of State of Multi-Phase Epoxy-Based Composite (Al-MnO2-Epoxy)

    DTIC Science & Technology

    2010-10-01

    There are several studies in the literature regarding the equation of state of alumina-epoxy composites. Although these single component systems...paper presents the shock equation of state results on a multi-phase composite Al-MnO2-epoxy. Equation of state experiments were conducted using three...The experimental equation of state data is compared to volume averaged and mesoscale mixture models.

  10. Shock Wave Structure in Particulate Composites

    NASA Astrophysics Data System (ADS)

    Rauls, Michael; Ravichandran, Guruswami

    2015-06-01

    Shock wave experiments are conducted on a particulate composite consisting of a polymethyl methacrylate (PMMA) matrix reinforced by glass beads. Such a composite with an impedance mismatch of 4.3 closely mimics heterogeneous solids of interest such as concrete and energetic materials. The composite samples are prepared using a compression molding process. The structure and particle velocity rise times of the shocks are examined using forward ballistic experiments. Reverse ballistic experiments are used to track how the interface density influences velocity overshoot above the steady state particle velocity. The effects of particle size (0.1 to 1 mm) and volume fraction of glass beads (30-40%) on the structure of the leading shock wave are investigated. It is observed that the rise time increases with increasing particle size and scales linearly for the range of particle sizes considered here. Results from numerical simulations using CTH are compared with experimental results to gain insights into wave propagation in heterogeneous particulate composites.

  11. Process for producing dispersed particulate composite materials

    DOEpatents

    Henager, Jr., Charles H.; Hirth, John P.

    1995-01-01

    This invention is directed to a process for forming noninterwoven dispersed particulate composite products. In one case a composite multi-layer film product comprises a substantially noninterwoven multi-layer film having a plurality of discrete layers. This noninterwoven film comprises at least one discrete layer of a first material and at least one discrete layer of a second material. In another case the first and second materials are blended together with each other. In either case, the first material comprises a metalloid and the second material a metal compound. At least one component of a first material in one discrete layer undergoes a solid state displacement reaction with at least one component of a second material thereby producing the requisite noninterwoven composite film product. Preferably, the first material comprises silicon, the second material comprises Mo.sub.2 C, the third material comprises SiC and the fourth material comprises MoSi.sub.2.

  12. Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite

    SciTech Connect

    Sayuti, M.; Sulaiman, S.; Baharudin, B. T. H. T.; Arifin, M. K. A.; Suraya, S.; Vijayaram, T. R.

    2011-01-17

    This paper discusses the mechanical properties of Titanium Carbide (TiC) particulate reinforced aluminium-silicon alloy matrix composite. TiC particulate reinforced LM6 alloy matrix composites were fabricated by carbon dioxide sand molding process with different particulate weight fraction. Tensile strength, hardness and microstructure studies were conducted to determine the maximum load, tensile strength, modulus of elasticity and fracture surface analysis have been performed to characterize the morphological aspects of the test samples after tensile testing. Hardness values are measured for the TiC reinforced LM6 alloy composites and it has been found that it gradually increases with increased addition of the reinforcement phase. The tensile strength of the composites increased with the increase percentage of TiC particulate.

  13. Tailored interface and enhanced elastic modulus in epoxy-based composites in presence of branched poly(ethyleneimine) grafted multiwall carbon nanotubes.

    PubMed

    Rohini, Rani; Bose, Suryasarathi

    2015-03-28

    In this study, branched poly(ethyleneimine), BPEI, was synthesized from carboxylic acid terminated multi-walled carbon nanotubes (c-MWNTs) and characterized using FTIR, TEM and TGA. The BPEI was then chemically grafted onto MWNTs to enhance the interfacial adhesion with the epoxy matrix. The epoxy composites with c-MWNTs and the BPEI-g-MWNTs were prepared using a sonication and mechanical stirring method, followed by curing at 100 °C and post-curing at 120 °C. The dynamic mechanical thermal analysis showed an impressive 49% increment in the storage elastic modulus in the composites. In addition, the nanoindentation on the composites exhibited significant improvement in the hardness and decrease in the plasticity index in the presence of the BPEI-g-MWNTs. Thus, epoxy composites with BPEI-g-MWNTs can be further explored as self-healing materials.

  14. Influences of degree of curing and presence of inorganic fillers on the ultimate electrical properties of epoxy-based composites: experiment and simulation

    NASA Astrophysics Data System (ADS)

    Flandin, L.; Vouyovitch, L.; Beroual, A.; Bessede, J.-L.; Alberola, N. D.

    2005-01-01

    This paper describes both an experimental study and a numerical investigation of the breakdown field in particle reinforced thermosets. The experimental study revealed that the increase of the conversion degree (α) of the epoxy matrix improved the breakdown voltages both in divergent and quasi-homogeneous fields. It was also observed that the presence of the second phase (mineral filler) dispersed within the polymeric host led to apparently contradictory results depending on the nature of the electric field. The neat matrix exhibited a higher field to breakdown than that of the composite in a quasi-homogeneous field configuration whereas the opposite behaviour was evidenced in a point-plane configuration. It thus appeared that the filler can either increase or decrease the breakdown voltage, depending on the nature of the electrode configuration. To further understand this behaviour, a deterministic numerical simulation of the dielectric breakdown that accounts for the organization within real composites was developed. This numerical method, based on the resistor-short breakdown model was improved to directly account for the real phase arrangement within the samples through scanning electron micrographs. The simulation furnished the explanation for the apparent disagreement, showing that the inorganic particles protect the composite in divergent fields through a mechanism similar in nature to the so-called barrier effect, whereas the same fillers were responsible for a local intensification of the electric field and thereby a reduction of the dielectric strength in a quasi-homogeneous field.

  15. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    McInnis, E.L.; Bauman, B.D.; Williams, M.A.

    1996-04-09

    Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles. 2 figs.

  16. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    McInnis, Edwin L.; Scharff, Robert P.; Bauman, Bernard D.; Williams, Mark A.

    1995-01-01

    Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles.

  17. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    McInnis, E.L.; Scharff, R.P.; Bauman, B.D.; Williams, M.A.

    1995-01-17

    Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles. 2 figures.

  18. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    Bauman, Bernard D.; Williams, Mark A.; Bagheri, Reza

    1997-12-02

    Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles.

  19. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    McInnis, Edwin L.; Bauman, Bernard D.; Williams, Mark A.

    1996-04-09

    Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles.

  20. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    Bauman, B.D.; Williams, M.A.; Bagheri, R.

    1997-12-02

    Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles. 2 figs.

  1. Fatigue strengths of particulate filler composites reinforced with fibers.

    PubMed

    Bae, Ji-Myung; Kim, Kyoung-Nam; Hattori, Masayuki; Hasegawa, Koji; Yoshinari, Masao; Kawada, Eiji; Oda, Yutaka

    2004-06-01

    The aim of this study was to evaluate the dynamic fatigue strengths at 10(5) cycles and the strains of particulate filler composite resins with and without reinforcing fibers. An UHMWPE (Ribbond), a polyaromatic polyamide fiber (Fibreflex), and three glass fibers (GlasSpan, FibreKor, Vectris Frame) were used to reinforce the particulate filler composite resins. The fatigue properties were measured in three-point bending mode using a servohydraulic universal testing machine at a frequency of 5 Hz, until failure occurred or 10(5) cycles had been completed. The fatigue strengths at 10(5) cycles were determined by the staircase method. The fractured aspects of specimens were evaluated by an optical and scanning electron microscope. The fatigue strengths of particulate filler composite resins were 49-57 MPa, and those of fiber-reinforced were 90-209 MPa. Unidirectional glass fibers showed higher reinforcing effects on the fatigue strengths of composite resins. The strain of UHMWPE-reinforced composite was largest.

  2. Experimental study on cellulose particulate and its composites

    NASA Astrophysics Data System (ADS)

    Srinivasababu, Nadendla

    2016-05-01

    Anselme Payen has discovered cellulose after conducting rigorous experiments on wood. In this work an attempt is made to reinforce cellulose particulate into polyester matrix from 1.84 - 9.18 wt % and the lamina is manufactured by JMFIL technique. The fabricated lamina is cut into specimens for various tests as per ASTM standards. Tensile strength of 22.61 MPa is achieved at 1.84 % of cellulose content in composites. Then the cellulose composites at 1.89% of reinforcement level showed 55.57 MPa, 1.86 GPa flexural strength, modulus respectively. `C' kind of failure is visualized for all the specimens and volume fractions during impact test. The cellulose particulate is also analyzed for its morphology, size.

  3. Three-Dimensional Characterization of Polydisperse Particulate Composites from Microtomography

    DTIC Science & Technology

    2011-06-01

    Computing overall elastic constants of poly- disperse particulate composites from microtomographic data. J. Mech. Phys. Solids . Submitted for publication...particles are completely solid and have no hollow cavities, the 6-point connectivity criterion was used because of its more liberal results. Due to...individual solid particles. Finally, particles which touch the border of the image (and therefore might be incomplete) are removed in the border kill

  4. Silkworm cocoons inspire models for random fiber and particulate composites

    SciTech Connect

    Chen Fujia; Porter, David; Vollrath, Fritz

    2010-10-15

    The bioengineering design principles evolved in silkworm cocoons make them ideal natural prototypes and models for structural composites. Cocoons depend for their stiffness and strength on the connectivity of bonding between their constituent materials of silk fibers and sericin binder. Strain-activated mechanisms for loss of bonding connectivity in cocoons can be translated directly into a surprisingly simple yet universal set of physically realistic as well as predictive quantitative structure-property relations for a wide range of technologically important fiber and particulate composite materials.

  5. Silkworm cocoons inspire models for random fiber and particulate composites

    NASA Astrophysics Data System (ADS)

    Chen, Fujia; Porter, David; Vollrath, Fritz

    2010-10-01

    The bioengineering design principles evolved in silkworm cocoons make them ideal natural prototypes and models for structural composites. Cocoons depend for their stiffness and strength on the connectivity of bonding between their constituent materials of silk fibers and sericin binder. Strain-activated mechanisms for loss of bonding connectivity in cocoons can be translated directly into a surprisingly simple yet universal set of physically realistic as well as predictive quantitative structure-property relations for a wide range of technologically important fiber and particulate composite materials.

  6. Solid-particle erosion of aluminum/particulate ceramic composites

    SciTech Connect

    Goretta, K.C.; Wu, W.; Routbort, J.L. ); Rohatgi, P.K. )

    1990-06-01

    Impact erosion of 2014 aluminum, 2014 aluminum + 20 vol % particulate silicon carbide, and 2014 aluminum + 20 vol % particulate aluminum oxide has been studied at room temperature. The alloys were tested in the as-received and heat-treated conditions. Experiments were conducted with aluminum oxide abrasive in vacuum in a slinger-type apparatus over a range of abrasive size, velocity, and angle of impact. Erosion rates were influenced by reinforcement and heat treatment. Reduced ductility, both overall and local, attributed to reinforcement or heat treatment, caused, under most conditions, more rapid erosion of the composites. The data suggest that erosion rate can be minimized by proper microstructural control, involving reducing reinforcement segregation and the amount of intermetallic compounds. 37 refs., 7 figs.

  7. Morphology development of layered silicate epoxy based nanocomposites

    NASA Astrophysics Data System (ADS)

    Benson Tolle, Tia

    2005-07-01

    Nanotailoring of polymeric materials offers significant benefits in terms of new and improved properties or new property trade spaces. Significant improvements to thermoplastics have been demonstrated over the past decade stimulated by the pioneering work of Kojima, Usuki, and Okada. The ability to nanotailor epoxy-based composites could have significant payoffs to aerospace and non-aerospace applications. However the dynamic nature of a crosslinking system such as epoxies poses unique challenges to the development of controlled morphologies. Before ultimate control of morphology and material design towards property enhancements can occur, fundamental understanding of how morphologies of various scales develop with processing parameters must be developed. This dissertation summarizes the effects of various processing variables on the development of morphology within organically modified layered silicate-epoxy-amine materials. The effect of various morphologies on fracture behavior is also examined, and suggests that ordered morphologies on the nanoscale can provide for effective toughening of epoxies.

  8. Corrosion behavior of a particulate metal-matrix composite

    SciTech Connect

    Bertolini, L.; Brunella, M.F.; Candiani, S.

    1999-04-01

    The corrosion behavior of a particulate-reinforced metal-matrix composite (MMC) with an Al 6061-T6 (UNS A96061, Al-Mg-Si) matrix and 10 vol% alumina (Al{sub 2}O{sub 3}) particles was studied. The material was tested in different extrusion and forging conditions. Potentiodynamic polarization tests were carried out in aerated and deaerated sodium chloride (NaCl) solutions with concentrations from 0.06 N up to saturation to study pitting corrosion initiation. Three-month immersion tests were performed in aerated solutions. Results showed pitting corrosion initiated in aerated solutions, even for the lower chloride concentration. No significant influence of Al{sub 2}O{sub 3} particles on corrosion susceptibility of the matrix was observed. However, corrosion attacks occurred preferentially in the vicinity of the reinforcing particles. Extrusion or forging treatment did not affect corrosion behavior of the composite material significantly.

  9. Composition and oxidation state of sulfur in atmospheric particulate matter

    NASA Astrophysics Data System (ADS)

    Longo, Amelia F.; Vine, David J.; King, Laura E.; Oakes, Michelle; Weber, Rodney J.; Huey, Lewis Gregory; Russell, Armistead G.; Ingall, Ellery D.

    2016-10-01

    The chemical and physical speciation of atmospheric sulfur was investigated in ambient aerosol samples using a combination of sulfur near-edge x-ray fluorescence spectroscopy (S-NEXFS) and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the composition and oxidation state of sulfur in common primary emission sources and ambient particulate matter collected from the greater Atlanta area. Ambient particulate matter samples contained two oxidation states: S0 and S+VI. Ninety-five percent of the individual aerosol particles (> 1 µm) analyzed contain S0. Linear combination fitting revealed that S+VI in ambient aerosol was dominated by ammonium sulfate as well as metal sulfates. The finding of metal sulfates provides further evidence for acidic reactions that solubilize metals, such as iron, during atmospheric transport. Emission sources, including biomass burning, coal fly ash, gasoline, diesel, volcanic ash, and aerosolized Atlanta soil, and the commercially available bacterium Bacillus subtilis, contained only S+VI. A commercially available Azotobacter vinelandii sample contained approximately equal proportions of S0 and S+VI. S0 in individual aerosol particles most likely originates from primary emission sources, such as aerosolized bacteria or incomplete combustion.

  10. Fracture Analysis of Particulate Reinforced Metal Matrix Composites

    NASA Technical Reports Server (NTRS)

    Min, James B.; Cornie, James A.

    2013-01-01

    A fracture analysis of highly loaded particulate reinforced composites was performed using laser moire interferometry to measure the displacements within the plastic zone at the tip of an advancing crack. Ten castings were made of five different particulate reinforcement-aluminum alloy combinations. Each casting included net-shape specimens which were used for the evaluation of fracture toughness, tensile properties, and flexure properties resulting in an extensive materials properties data. Measured fracture toughness range from 14.1 MPa for an alumina reinforced 356 aluminum alloy to 23.9 MPa for a silicon carbide reinforced 2214 aluminum alloy. For the combination of these K(sub Ic) values and the measured tensile strengths, the compact tension specimens were too thin to yield true plane strain K(sub Ic) values. All materials exhibited brittle behavior characterized by very small tensile ductility suggesting that successful application of these materials requires that the design stresses be below the elastic limit. Probabilistic design principles similar to those used with ceramics are recommended when using these materials. Such principles would include the use of experimentally determined design allowables. In the absence of thorough testing, a design allowable stress of 60 percent of the measured ultimate tensile stress is recommended.

  11. Compositional Analysis of Fine Particulate Matter in Fairbanks, Alaska

    NASA Astrophysics Data System (ADS)

    Nattinger, K.; Simpson, W. R.; Huff, D.

    2015-12-01

    Fairbanks, AK experiences extreme pollution episodes that result in winter violations of the fine particulate matter (PM2.5) National Ambient Air Quality Standards. This poses a significant health risk for the inhabitants of the area. These high levels result from trapping of pollution in a very shallow boundary layer due to local meteorology, but the role of primary (direct emission) of particulate matter versus secondary production (in the atmosphere) of particulate matter is not understood. Analysis of the PM2.5 composition is being conducted to provide insight into sources, trends, and chemistry. Methods are developed to convert carbon data from IMPROVE (post-2009 analysis method) to NIOSH (pre-2009 method) utilizing blank subtraction, sampler bias adjustment, and inter-method correlations from co-located samples. By converting all carbon measurements to a consistent basis, long-term trends can be analyzed. The approach shows excellent mass closure between PM2.5 mass reconstructed from constituents and gravimetric-analyzed mass. This approach could be utilized in other US locations where the carbon analysis methods also changed. Results include organic and inorganic fractional mass percentages, analyzed over an eight-year period for two testing sites in Fairbanks and two in the nearby city of North Pole. We focus on the wintertime (Nov—Feb) period when most air quality violations occur and find that the particles consist primarily of organic carbon, with smaller percentages of sulfate, elemental carbon, ammonium, and nitrate. The Fairbanks area PM2.5 organic carbon / elemental carbon partitioning matches the source profile of wood smoke. North Pole and Fairbanks PM2.5 have significant compositional differences, with North Pole having a larger percentage of organic matter. Mass loadings in SO42-, NO3-, and total PM2.5 mass correlate with temperature. Multi-year temporal trends show little if any change with a strong effect from temperature. Insights from this

  12. Interfacial preferential dissolution on silicon carbide particulate/aluminum composites

    SciTech Connect

    Yao, H.Y.; Zhu, R.Z.

    1998-07-01

    Previous studies on corrosion of discontinuously reinforced aluminum alloy composites have assumed that the role of the reinforcement-matrix interface is merely as a preferable site for pitting. In this work, the interfacial preferential dissolution (IPD) occurring on silicon carbide particulate/aluminum (SiC{sub p}/Al) composites in a medium of aqueous sodium chloride (NaCl) solution was studied. IPD was quite distinct from pitting. IPD occurred on the composites with either a pure aluminum matrix or an aluminum alloy Al 2024 (UNS A92024) matrix, whether they were fabricated by a cast process or by a powder metallurgy process. In the light of elastoplastic mechanics, the width of the plastically deformed zone around SiC particles (created by the contraction misfit between SiC particles and the matrix during quenching) was deduced to be 0.5 D, where D is the diameter of the SiC particles. This was in agreement with the measured width of the IPD region (0.3 D to 0.4 D). It was concluded that IPD was caused by the poor integrity of the surface oxide film upon the plastically deformed zone near the interface and was independent of the chemical, metallurgical, and galvanic coupling factors around the interface, if any. A copper-deposition experiment indicated this poor integrity. IPD caused increased dissolution at SiC clusters and uniform corrosion for the composites with high SiC content. Moreover, IPD and pitting suppressed each other by a means of cathodic protection.

  13. Method of producing particulate-reinforced composites and composites produced thereby

    DOEpatents

    Han, Qingyou; Liu, Zhiwei

    2015-12-29

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

  14. Method of producing particulate-reinforced composites and composites produced thereby

    DOEpatents

    Han, Qingyou; Liu, Zhiwei

    2013-12-24

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

  15. Stress development in particulate, nano-composite and polymeric coatings

    NASA Astrophysics Data System (ADS)

    Jindal, Karan

    2009-12-01

    The main goal of this research is to study the stress, structural and mechanical property development during the drying of particulate coatings, nano-composite coatings and VOC compliant refinish clearcoats. The results obtained during this research establish the mechanism for the stress development during drying in various coating systems. Coating stress was measured using a controlled environment stress apparatus based on cantilever deflection principle. The stress evolution in alumina coatings made of 0.4 mum size alumina particles was studied and the effect of a lateral drying was investigated. The stress does not develop until the later stages of drying. A peak stress was observed during drying and the peak stress originates due to the formation of pendular rings between the particles. Silica nanocomposite coatings were fabricated from suspension of nano sized silicon dioxide particles (20 nm) and polyvinyl alcohol (PVA) polymer. The stress in silica nano-composite goes through maximum as the amount of polymer in the coating increases. The highest final stress was found to be ˜ 110MPa at a PVA content of 60 wt%. Observations from SEM, nitrogen gas adsorption, camera imaging, and nano-indentation were also studied to correlate the coatings properties during drying to measured stress. A model VOC compliant two component (2K) acrylic-polyol refinish clearcoat was prepared to study the effects of a new additive on drying, curing, rheology and stress development at room temperature. Most of the drying of the low VOC coatings occurred before appreciable (20%) crosslinking. Tensile stress developed in the same timeframe as drying and then relaxed over a longer time scale. Model low VOC coatings prepared with the additive had higher peak stresses than those without the additive. In addition, rheological data showed that the additive resulted in greater viscosity buildup during drying.

  16. Fine particulate chemical composition and light extinction at Meadview, AZ.

    PubMed

    Eatough, Delbert J; Cui, Wenxuan; Hull, Jeffery; Farber, Robert J

    2006-12-01

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr day-night samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was +/- 0.6 microg/m3 organic material, +/- 0.3 microg/m3 ammonium sulfate, and +/- 0.07 microg/m3 ammonium nitrate. Data were also available on fine particulate crustal material, fine and coarse particulate mass from the Interagency Monitoring of Protected Visual Environments sampling system, and relative humidity (RH), light absorption, particle scattering, and light extinction measurements from Project MOHAVE. An extinction budget was obtained using mass scattering coefficients estimated from particle size distribution data. Literature data were used to estimate the change in the mass scattering coefficients for the measured species as a function of RH and for the absorption of light by elemental carbon. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. During periods of highest light extinction, contributions from fine particulate organic material, sulfate, and light-absorbing carbon dominated the extinction of light by particles. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides

  17. Fine particulate chemical composition and light extinction at Meadview, AZ

    SciTech Connect

    Delbert J. Eatough; Wenxuan Cui; Jeffery Hull; Robert J. Farber

    2006-12-15

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr daynight samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was {+-} 0.6 {mu}g/m{sup 3} organic material, {+-} 0.3 {mu}g/m{sup 3} ammonium sulfate, and {+-} 0.07 {mu}g/m{sup 3} ammonium nitrate. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides sources in the region indicate that the major anthropogenic contributors to light extinction were from the Los Angeles, CA, and Las Vegas, NV, urban areas. Mohave Power Project associated secondary sulfate was a negligible contributor to light extinction. 49 refs., 12 figs., 7 tabs.

  18. Ambient background particulate composition, outdoor natural background: interferents/clutter

    NASA Astrophysics Data System (ADS)

    Paterno, Dorothea

    2012-06-01

    It has proven a very difficult task to discriminate an actual BW threat from the natural occurring ambient particulate aerosol, which includes a significant fraction of particles consisting of mixed mineral and biological material. The interferent particles [clutter] (bio and non bio) concentration varies widely both by location, weather and season and diurnally. Naturally occurring background particulates are composed of fungal and bacterial spores both fragments and components, plant fragments and debris, animal fragments and debris, all of which may be associated with inert dust or combustion material. Some or all of which could also be considered to be an interferent to a biological warfare detector and cause these biodector systems to cause False Alarms by non specific BW bio detectors. I will share analysis of current long term background data sets.

  19. Damage healing ability of a shape-memory-polymer-based particulate composite with small thermoplastic contents

    NASA Astrophysics Data System (ADS)

    Nji, Jones; Li, Guoqiang

    2012-02-01

    The purpose of this study is to investigate the potential of a shape-memory-polymer (SMP)-based particulate composite to heal structural-length scale damage with small thermoplastic additive contents through a close-then-heal (CTH) self-healing scheme that was introduced in a previous study (Li and Uppu 2010 Comput. Sci. Technol. 70 1419-27). The idea is to achieve reasonable healing efficiencies with minimal sacrifice in structural load capacity. By first closing cracks, the gap between two crack surfaces is narrowed and a lesser amount of thermoplastic particles is required to achieve healing. The particulate composite was fabricated by dispersing copolyester thermoplastic particles in a shape memory polymer matrix. It is found that, for small thermoplastic contents of less than 10%, the CTH scheme followed in this study heals structural-length scale damage in the SMP particulate composite to a meaningful extent and with less sacrifice of structural capacity.

  20. Quantifying Uncertainties in the Thermo-Mechanical Properties of Particulate Reinforced Composites

    NASA Technical Reports Server (NTRS)

    Mital, Subodh K.; Murthy, Pappu L. N.

    1999-01-01

    The present paper reports results from a computational simulation of probabilistic particulate reinforced composite behavior. The approach consists use of simplified micromechanics of particulate reinforced composites together with a Fast Probability Integration (FPI) technique. Sample results are presented for a Al/SiC(sub p)(silicon carbide particles in aluminum matrix) composite. The probability density functions for composite moduli, thermal expansion coefficient and thermal conductivities along with their sensitivity factors are computed. The effect of different assumed distributions and the effect of reducing scatter in constituent properties on the thermal expansion coefficient are also evaluated. The variations in the constituent properties that directly effect these composite properties are accounted for by assumed probabilistic distributions. The results show that the present technique provides valuable information about the scatter in composite properties and sensitivity factors, which are useful to test or design engineers.

  1. Magnitude and composition of sinking particulate phosphorus fluxes in Santa Barbara Basin, California

    NASA Astrophysics Data System (ADS)

    Sekula-Wood, Emily; Benitez-Nelson, Claudia R.; Bennett, Melissa A.; Thunell, Robert

    2012-06-01

    The composition and bioavailability of particulate P influence marine biological community production on both modern and geologic time-scales, and continental margins play a critical role in the supply, modification, and storage of particulate P. This study examined particulate P cycling in the Santa Barbara Basin (SBB) off the coast of southern California using a ˜520 m deep-moored sediment trap deployed from 1993-2006 and a sediment core collected in 2005 directly beneath the sediment trap at 590 m. Total particulate P (TPP), particulate inorganic P (PIP), and particulate organic P (POP) were quantified using a 5-step sequential extraction method (SEDEX) that chemically separates PIP into loosely bound, oxide-bound, authigenic, and detrital P phases. POP fluxes, while similar in magnitude to other coastal regions (22 ± 10 μmol m-2 d-1) were a small component of the TPP pool (15%). Seasonal trends revealed significant increases in POP fluxes during upwelling due to increased biological production in surface waters by organisms that increased mineral ballast. High particulate organic carbon (POC) to POP ratios (337 ± 18) further indicated rapid and efficient remineralization of POP relative to POC as particles sank through the oxic water column; however, further reduction of POP ceased in the deeper anoxic waters. Loosely bound, oxide-bound, and authigenic P, dominated the TPP pool, with PIP fluxes substantially higher than those measured in other coastal settings. Strong correlations between oxide-associated, authigenic, and detrital P fluxes with lithogenic material indicated a terrestrial source associated with riverine discharge. Furthermore, more than 30% of the loosely bound and oxide-bound P was remineralized prior to burial, with the magnitude of dissolution far exceeding that of POP. These results highlight the dynamic nature of the particulate P pool in coastal ecosystems and how changes in P source can alter the composition and lability of P that

  2. Uncertainties in the Thermal and Mechanical Properties of Particulate Composites Quantified

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Mital, Subodh K.

    2001-01-01

    Particle-reinforced composites are candidate materials for a wide variety of aerospace and nonaerospace applications. The high costs and technical difficulties involved with the use of many fiber-reinforced composites often limit their use in many applications. Consequently, particulate composites have emerged as viable alternatives to conventional fiber-reinforced composites. Particulate composites can be processed to near net shapepotentially reducing the manufacturing costs. They are candidate materials where shock or impact properties are important. For example, particle-reinforced metal matrix composites have shown great potential for many automotive applications. Typically, these materials are aluminum matrix reinforced with SiC or TiC particles. Reinforced concrete can also be thought of as a particle-reinforced composite. In situ ceramics can be modeled as particulate composites and are candidate materials for many high-temperature applications. The characterization of these materials is fundamental to their reliable use. It has been observed that the overall properties of these composites exhibit scatter because of the uncertainty in the constituent material properties, and fabrication-related parameters.

  3. Influence of reaction condition on viscosity of polyurethane modified epoxy based on glycerol monooleate

    NASA Astrophysics Data System (ADS)

    Triwulandari, Evi; Ramadhan, Mohammad Kemilau; Ghozali, Muhammad

    2017-01-01

    Polyurethane modified epoxy based on glycerol monooleate (PME-GMO) was synthesized. GMO as polyol for synthesis of PME-GMO was synthesized via Fisher Esterification between oleic acid from palm oil and glycerol by using sulfuric acid as catalyst with time variation i.e. 3, 4, 5 and 6 hours at 160°C. Characterizations of GMO were carried out by analysis of acid number, hydroxyl value and FTIR. The data show that the conversion of oleic acid to ester compound is directly proportional with the increasing of reaction time but the enhancement is not significant after 3 hours. Furthermore, GMO product was used as polyol for modification of epoxy with polyurethane. Modification of epoxy with polyurethane was performed by reacted epoxy, tolonate and GMO simultaneously in one step. In this research, the reaction condition was varied i.e. time reaction (0.5; 1; 1.5; 2; 2.5 hours), composition of polyurethane used (10%, 20% toward epoxy) and rasio of tolonate and GMO (NCO/OH ratio) as component of polyurethane (1.5 and 2.5). Characterization of polyurethane modified epoxy based on glycerol (PME-GMO) was conducted by viscosity and FTIR analysis. The viscosity of PME-GMO increased with increasing of reaction time, polyurethane composition and NCO/OH ratio.

  4. Depolarization field effect on dielectric and piezoelectric properties of particulate ferroelectric ceramic-polymer composites

    NASA Astrophysics Data System (ADS)

    Ma, Fengde D.; Wang, Yu U.

    2015-03-01

    The effects of depolarization field on the dielectric and piezoelectric properties of ferroelectric ceramic particle-filled polymer-matrix composites are investigated at the underlying domain level. Phase field modeling and simulation reveals that the macroscopic properties of the composites are dominated by depolarization field effect, which depends on the arrangement and alignment rather than the size or internal grain structure of the ferroelectric particulates. It is found that 0-3 particulate composites with random dispersion of ferroelectric particles behave essentially like linear dielectric rather than ferroelectric materials, and domain-level analysis reveals the physical mechanism for lack of domain switching or hysteresis as attributed to strong depolarization effect. Thus, without effective reduction or elimination of the depolarization field, the composites cannot benefit from the functional fillers regardless of their superior properties. In order to exhibit the desired ferroelectric behaviors, it necessitates continuous ferroelectric phase connectivity in the composites.

  5. Effective conductivity of particulate polymer composite electrolytes using random resistor network method

    SciTech Connect

    Kalnaus, Sergiy; Sabau, Adrian S; Newman, Sarah M; Tenhaeff, Wyatt E; Daniel, Claus; Dudney, Nancy J

    2011-01-01

    The effective DC conductivity of particulate composite electrolytes was obtained by solving electrostatics equations using random resistors network method in three dimensions. The composite structure was considered to consist of three phases: matrix, particulate filler, and conductive shell that surrounded each particle; each phase possessing a different conductivity. Different particle size distributions were generated using Monte Carlo simulations. Unlike effective medium formulations, it was shown that the random resistors network method was able to predict percolation thresholds for the effective composite conductivity. It was found that the mean particle radius has a higher influence on the effective composite conductivity compared to the effect of type of the particle size distributions that were considered. The effect of the shell thickness on the composite conductivity has been investigated. It was found that the conductivity enhancement due to the presence of the conductive shell phase becomes less evident as the shell thickness increases.

  6. Physico-mechanical and tribological properties of Grewia Optiva fiber/bio-particulates hybrid polymer composites

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Gangil, Brijesh; Patel, Vinay Kumar

    2016-05-01

    Lack of resources and increasing environmental issues has received widespread attention for the development of natural fiber/ particulate reinforced hybrid polymer composites. In the present investigation the authors use (GO) Grewia Optiva as the main reinforcement and rice husk/wheat straw as additional particulates for improving the mechanical and wear properties of polymer composites. The samples were prepared by hand layup technique according to ASTM standards. The results indicated that incorporation of wheat straw with GO polymer materials exhibited better hardness (2.5 times harder) and less wear (0.85 times) than mono GO fiber polymer composites (GOFRP). Moreover, Rice husk filled GOFRP shows superior impact energy among the all set of composites. Water absorption behavior was also discussed in this investigation.

  7. Development of an epoxy-based monolith used for the affinity capturing of Escherichia coli bacteria.

    PubMed

    Peskoller, Caroline; Niessner, Reinhard; Seidel, Michael

    2009-05-01

    An epoxy-based monolith has been developed for use as hydrophilic support in bioseparation. This monolith is produced by self-polymerization of polyglycerol-3-glycidyl ether in organic solvents as porogens at room temperature within 1 h. One receives a highly cross-linked structure that provides useful mechanical properties. The porosity and pore diameter can be controlled by varying the composition of the porogen. In this work, an epoxy-based monolith with a high porosity (79%) and large pore size (22 microm) is prepared and used in affinity capturing of bacterial cells. These features allow the passage of bacterial cells through the column. As affinity ligand polymyxin B is used, which allows the binding of gram-negative bacteria. The efficiency of the monolithic affinity column is studied with Escherichia coli spiked in water. Bacterial cells are concentrated on the column at pH 4 and eluted with a recovery of 97+/-3% in 200 microL by changing the pH value without impairing viability of bacteria. The dynamic capacity for the monolithic column is nearly independent of the flow rate (4x10(9)cells/column). Thereby, it is possible to separate and enrich gram-negative bacterial cells, such as E. coli, with high flow rates (10 mL/min) and low back pressure (<1 bar) in a volume as low as 200 microL compatible for real-time polymerase chain reaction, microarray formats, and biosensors.

  8. Assessment of particulate cellulose epoxy composites manufactured by JMFIL under impact load

    NASA Astrophysics Data System (ADS)

    Srinivasababu, Nadendla

    2015-08-01

    Increase in environmental concern towards sustainable development invites the development of new materials which are eco-friendly to satisfy various engineering needs. The present work introduces a new manufacturing method i.e. "Just Mold Fill and Immediate Loading" to prepare epoxy composites reinforced at different contents of particulate cellulose. The fabricated composites specimens are post processed and machined, tested as per ASTM procedures under impact load.

  9. Recycling of ceramic particulate reinforced aluminium metal matrix composites

    SciTech Connect

    Sharma, S.C.; Murthy, C.S.C.; Kamath, R.; Vinai Babu, B.R.; Satish, B.M.; Girish, B.M.

    1995-12-31

    The aluminum matrix composites with ceramic dispersoids can be separated by the density difference concept. In the proposed work, composite scrap is recycled using an oil fired furnace. The scrap is melted in the furnace and temperature is maintained below 740 degree centigrade. Because of the density difference the lighter dispersoids will float and heavier dispersoids will settle down. The clean melt is separated be removing the floating and settled dispersoids, and then filtering using ceramic filters.

  10. Method of making metal matrix composites reinforced with ceramic particulates

    DOEpatents

    Cornie, James A.; Kattamis, Theodoulos; Chambers, Brent V.; Bond, Bruce E.; Varela, Raul H.

    1989-01-01

    Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys.

  11. Method of making metal matrix composites reinforced with ceramic particulates

    DOEpatents

    Cornie, J.A.; Kattamis, T.; Chambers, B.V.; Bond, B.E.; Varela, R.H.

    1989-08-01

    Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys. 2 figs.

  12. Variations in atmospheric concentrations and isotopic compositions of gaseous and particulate boron in Shizuoka City, Japan

    NASA Astrophysics Data System (ADS)

    Sakata, Masahiro; Phan, Hang Giang; Mitsunobu, Satoshi

    2017-01-01

    To clarify the partitioning and isotopic fractionation of boron (B) into the gas and particle phases in the atmosphere, the concentrations and isotopic compositions of gaseous and particulate B were measured concurrently for more than one year at a site in Shizuoka City, Japan. This area has few anthropogenic sources of B, such as coal combustion facilities. Gaseous B concentration showed clearly a seasonal variation, increasing during summer and decreasing during winter. Conversely, particulate B concentration tended to decrease during the warm season and increase during winter. The increase in gaseous B concentration during summer is attributable to the enhanced emissions of B from sea-salt degassing owing to higher temperatures and the predominance of winds from the Pacific Ocean. Moreover, the decrease in gaseous B concentration and the increase in particulate B concentration during winter is probably due to the enhanced condensation of gaseous B on atmospheric particles. The δ11B values of gaseous and particulate B varied largely, and did not indicate a distinctive seasonal variation. A positive correlation was observed between the δ11B values of gaseous and particulate B (R2 = 0.518, P < 0.001). Moreover, the δ11B values of particulate B were approximately 0-20‰ lower than those of gaseous B. There is an isotopic fractionation (ΔB(OH)4- -B(OH)3) of about -20‰ between B(OH)3 and B(OH)4- species in solution (Kakihana et al., 1977). This tends to support the hypotheses that gaseous B is transformed to particulate B through the reaction of condensed B(OH)3 with chemical constituents on particles to precipitate borates, and that the condensed B(OH)3 remaining on particles is unstable and evaporates.

  13. Microstructural Design & Optimization of Highly Filled Epoxy Based Composites

    DTIC Science & Technology

    2009-11-01

    Hutto and Dr. Jim Simpson for valuable discussions regarding design of experiments and analysis of the problem presented in this paper. Opinions...determined using the decompose/shift/reconstruct (DSR) method described by Mulliken and Boyce [14]. A straight line was then fitted to the low and...Research (AFOSR/NA), Dr. Joan Fuller, Program Manager. Dr. Jordan would like to thank Mr. Greg Hutto and Dr. Jim Simpson for valuable discussions

  14. Global Chemical Composition of Ambient Fine Particulate Matter for Exposure Assessment

    PubMed Central

    2015-01-01

    Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004–2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrations were dominated by particulate organic mass (11.9 ± 7.3 μg/m3), secondary inorganic aerosol (11.1 ± 5.0 μg/m3), and mineral dust (11.1 ± 7.9 μg/m3). Secondary inorganic PM2.5 concentrations exceeded 30 μg/m3 over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 μg/m3) could be almost as large as from fossil fuel combustion sources (17 μg/m3). These estimates offer information about global population exposure to the chemical components and sources of PM2.5. PMID:25343705

  15. ICAN/PART: Particulate composite analyzer, user's manual and verification studies

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Murthy, Pappu L. N.; Mital, Subodh K.

    1996-01-01

    A methodology for predicting the equivalent properties and constituent microstresses for particulate matrix composites, based on the micromechanics approach, is developed. These equations are integrated into a computer code developed to predict the equivalent properties and microstresses of fiber reinforced polymer matrix composites to form a new computer code, ICAN/PART. Details of the flowchart, input and output for ICAN/PART are described, along with examples of the input and output. Only the differences between ICAN/PART and the original ICAN code are described in detail, and the user is assumed to be familiar with the structure and usage of the original ICAN code. Detailed verification studies, utilizing dim dimensional finite element and boundary element analyses, are conducted in order to verify that the micromechanics methodology accurately models the mechanics of particulate matrix composites. ne equivalent properties computed by ICAN/PART fall within bounds established by the finite element and boundary element results. Furthermore, constituent microstresses computed by ICAN/PART agree in average sense with results computed using the finite element method. The verification studies indicate that the micromechanics programmed into ICAN/PART do indeed accurately model the mechanics of particulate matrix composites.

  16. Global Chemical Composition of Ambient Fine Particulate Matter for Exposure Assessment

    DOE PAGES

    Philip, Sajeev; Martin, Randall V.; van Donkelaar, Aaron; ...

    2014-10-24

    Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004–2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrationsmore » were dominated by particulate organic mass (11.9 ± 7.3 μg/m3), secondary inorganic aerosol (11.1 ± 5.0 μg/m3), and mineral dust (11.1 ± 7.9 μg/m3). Secondary inorganic PM2.5 concentrations exceeded 30 μg/m3 over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 μg/m3) could be almost as large as from fossil fuel combustion sources (17 μg/m3). In conclusion, these estimates offer information about global population exposure to the chemical components and sources of PM2.5.« less

  17. Method of producing particulate-reinforced composites and composties produced thereby

    DOEpatents

    Han, Qingyou; Liu, Zhiwei

    2013-12-24

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intenisty acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaciton products comprise a solide particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particles-reinforced composite materials produced by such a process.

  18. Radiation induced effects on particulate composites from epoxy resin and fly-ash

    NASA Astrophysics Data System (ADS)

    Baccaro, S.; Bianchilli, B.; Casadio, C.; Rinaldi, G.

    1998-06-01

    In this paper gamma-radiation damages and effects on an epoxide matrix and on its particulate composite with coal fly ash have been studied; the curing of both formulations was carried out at room temperature by means of tetraethylenepentamine and of a tailored polyalkylenepolyaminophenolic product. The change on mechanical properties following the irradiation in air at room temperature has been tested as a function of the total absorbed dose. The chemical modification induced by the ionizing radiation on the matrices have been investigated by means of infrared spectrophotometry and differential scanning calorimetry. The high radiation resistance of the matrix and above all of the particulate composite suggests its use for the confinment of low and medium activity radwastes (nuclear or medical).

  19. Numerical Investigation for the Microstructural Effects on the Crack Growth Behavior of Particulate Composite Materials

    DTIC Science & Technology

    2006-07-26

    When the damage constitutive law is adopted in an analysis, we perform an incremental analysis, just like the case of elastoplasticity (see Okada...isotropic elastoplasticity . 2.4 Some other issues associated with the damage constitutive law-initiation of nonlinear deformation Material...ABSTRACT In present investigation, analyses for the damage evolution behavior of particulate composite materials by using the finite element method

  20. Combined mode I-mode III fracture toughness of a particulate reinforced metal-matrix composite

    NASA Technical Reports Server (NTRS)

    Manoharan, M.; Lewandowski, J. J.

    1991-01-01

    The aim of this investigation was to determine the fracture behavior of a particulate reinfored aluminum alloy composite under combined mode I-mode III loading conditions. A modified three-point bend specimen was used to carry out these tests. It was found that the mode I loading condition was energetically most favorable. Addition of mode III components to the system seems to increase the amount of redundant work during fracture without affecting the critical fracture criterion.

  1. Plutonium Finishing Plant (PFP) Waste Composition and High Efficiency Particulate Air Filter Loading

    SciTech Connect

    ZIMMERMAN, B.D.

    2000-12-11

    This analysis evaluates the effect of the Plutonium Finishing Plant (PFP) waste isotopic composition on Tank Farms Final Safety Analysis Report (FSAR) accidents involving high-efficiency particulate air (HEPA) filter failure in Double-Contained Receiver Tanks (DCRTs). The HEPA Filter Failure--Exposure to High Temperature or Pressure, and Steam Intrusion From Interfacing Systems accidents are considered. The analysis concludes that dose consequences based on the PFP waste isotopic composition are bounded by previous FSAR analyses. This supports USQD TF-00-0768.

  2. Evaluation of Johnson-Cook model constants for aluminum based particulate metal matrix composites

    NASA Astrophysics Data System (ADS)

    Hilfi, H.; Brar, N. S.

    1996-05-01

    High strain rate and high temperature response of three types of aluminum based particulate metal matrix ceramic composites is investigated by performing split Hopkinson pressure bar (SHPB) experiments. The composites are: NGP-2014 (15% SiC), NGT-6061 (15% SiC), and NGU-6061 (15% Al2O3), in which all the reinforcement materials are percentage by volume. Johnson-Cook constitutive model constants are evaluated from the high strain rate/high temperature data and implemented in a two dimensional finite element computer code (EPIC-2D) to simulate the penetration of an ogive nose tungsten projectile (23 grams) at a velocity 1.17 km/sec into the base 6061-T6 aluminum alloy and the composite NGU-6061. The simulated penetrations in the composite and in 6061-T6 aluminum agree with in 2%, in both materials, with the measured values.

  3. Microstructure and wear characteristics of si particulate reinforced al matrix composites

    NASA Astrophysics Data System (ADS)

    Song, Suk-Jin; Kim, Do-Hyang; Kim, Jun-Su

    1997-08-01

    In order to obtain a homogeneous distribution of fine Si particles in aluminium matrix and thus to improve the adaptability of Al-Si alloy for aerospace and automobile applications, Si particulate reinforced aluminium matrix composites have been processed by using powder metallurgy method. The Si pariticulates with 20-40 μm size and Al alloy powders were mixed, degassed and extruded at 350°C or 400°C depending on the composition of the matrix alloy. The microstructural characteristics of the composites such as interfacial stability at high temperatures have been investigated by various experimental techniques. Wear properties of the composites were investigated by using a pin-on-disk type wear tester. The results were compared with these obtained from the conventionally cast hypereutectic Al-Si alloys and discussed in terms of the observed microstructural characteristics and physical properties such as hardness and tensile properties.

  4. Chemical composition and mass closure of particulate matter at six urban sites in Europe

    NASA Astrophysics Data System (ADS)

    Sillanpää, Markus; Hillamo, Risto; Saarikoski, Sanna; Frey, Anna; Pennanen, Arto; Makkonen, Ulla; Spolnik, Zoya; Van Grieken, René; Braniš, Martin; Brunekreef, Bert; Chalbot, Marie-Cecile; Kuhlbusch, Thomas; Sunyer, Jordi; Kerminen, Veli-Matti; Kulmala, Markku; Salonen, Raimo O.

    The chemical composition of fine (PM 2.5) and coarse (PM 2.5-10) particulate matter was investigated in 7-week field campaigns of contrasting air pollution at six urban background sites in Europe. The campaigns were scheduled to include seasons of local public health concern due to high particulate concentrations or findings in previously conducted epidemiological studies. The sampling campaigns were carried out as follows: Duisburg/Germany October-November 2002 (autumn), Prague/Czech Republic November 2002-January 2003 (winter), Amsterdam/Netherlands January-March 2003 (winter), Helsinki/Finland March-May 2003 (spring), Barcelona/Spain March-May 2003 (spring) and Athens/Greece June-July 2003 (summer). Aerosol samples were collected in 3+4-day periods per week ( N=14) using two identical virtual impactors (VI). All the filter samples were analysed with the same instruments to obtain particulate mass, inorganic ions, total and watersoluble elements, and elemental and organic carbon content. The campaign means of PM 2.5 and PM 2.5-10 ranged from 8.3 to 30 and 5.4 to 29 μg m -3, respectively. The "wet and cool" seasons favoured a low coarse-to-fine particulate mass ratio (<1), whereas the ratio was high (>1) during the warmer and drier spring and summer campaigns. According to chemical mass closure, the major components in PM 2.5 were carbonaceous compounds (organic matter+elemental carbon), secondary inorganic ions and sea salt, whereas those in PM 2.5-10 were soil-derived compounds, carbonaceous compounds, sea salt and nitrate. The major and minor components together accounted for 79-106% and 77-96% of the gravimetrically measured PM 2.5 and PM 2.5-10 mass, respectively. In conclusion, the measured PM 2.5 and PM 2.5-10 in the campaigns could be reconstructed to a large extent with the help of harmonized particulate sampling and analysis of the selected chemical constituents. The health significance of the observed differences in chemical composition and emission

  5. Global Chemical Composition of Ambient Fine Particulate Matter for Exposure Assessment

    SciTech Connect

    Philip, Sajeev; Martin, Randall V.; van Donkelaar, Aaron; Lo, Jason Wai-Ho; Wang, Yuxuan; Chen, Dan; Zhang, Lin; Kasibhatla, Prasad S.; Wang, Siwen; Zhang, Qiang; Lu, Zifeng; Streets, David G.; Bittman, Shabtai; Macdonald, Douglas J.

    2014-10-24

    Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004–2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrations were dominated by particulate organic mass (11.9 ± 7.3 μg/m3), secondary inorganic aerosol (11.1 ± 5.0 μg/m3), and mineral dust (11.1 ± 7.9 μg/m3). Secondary inorganic PM2.5 concentrations exceeded 30 μg/m3 over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 μg/m3) could be almost as large as from fossil fuel combustion sources (17 μg/m3). In conclusion, these estimates offer information about global population exposure to the chemical components and sources of PM2.5.

  6. Does the composition of streamwater colloidal and particulate matter change during monsoon storms?

    NASA Astrophysics Data System (ADS)

    Prescott-Smith, J.; Pohlmann, M. A.; Perdrial, J. N.; Perdrial, N.; Troch, P. A.; Chorover, J.

    2012-12-01

    Streams draining mountain catchments are an important pathway for carbon and weathering products to leave the critical zone (CZ). During intense events such as North American monsoon related storms, shallow flow paths may dominate and introduce soil-derived particulate organic matter (POM), mineral particles and organo-mineral heteroaggregates, into the streams. However, it is not yet well understood how the composition of colloidal and particulate matter (PM) changes during the storm-fed hydrograph. We hypothesized that during small, low intensity storms (small hydrograph response) both organic and organo-mineral aggregates will dominate the suspended particulate load, and that during larger high intensity storms (distinct rise of stream water levels) there will be a significant increase in organic polysaccharide particulates during the rising limb and peak of the storm, with higher levels of minerals being re-introduced during the falling limb of the hydrograph. A headwater stream draining a small (1.3km2) watershed in the Santa Catalina Mountain Critical Zone Observatory (SCM-CZO) was sampled at high resolution (5 minute) intervals during monsoon storms, and solutions were cascade-filtered through polycarbonate filters of 8, 1.2, 0.4 and 0.025 μm pore size. The PM mass was determined and particles >8um were further analyzed using Fourier Transform Infrared (FTIR) microscopy. These qualitative spectral results were supplemented by the ultra-violet/visible and fluorescence spectra of the colloidal and dissolved (<1.2 μm and <0.4μm) matter in the same sample. Preliminary results for a low intensity storm suggest that three main types of particles dominated: i) POM, ii) silicates and hydroxide minerals and iii) OM-mineral aggregates. POM was most abundant and chemical functional group composition resembled that of the <1.2μm and <0.4μm filtrates (e.g. distinct phenolic-OH and aliphatic C-H stretching bands were observed in both sets of spectra). Bands

  7. Variation in the Composition and In Vitro Proinflammatory Effect of Urban Particulate Matter from Different Sites

    PubMed Central

    Manzano-León, Natalia; Quintana, Raúl; Sánchez, Brisa; Serrano, Jesús; Vega, Elizabeth; Vázquez-López, Inés; Rojas-Bracho, Leonora; López-Villegas, Tania; O’Neill, Marie S.; Vadillo-Ortega, Felipe; De Vizcaya-Ruiz, Andrea; Rosas, Irma

    2015-01-01

    Spatial variation in particulate matter–related health and toxicological outcomes is partly due to its composition. We studied spatial variability in particle composition and induced cellular responses in Mexico City to complement an ongoing epidemiologic study. We measured elements, endotoxins, and polycyclic aromatic hydrocarbons in two particle size fractions collected in five sites. We compared the in vitro proinflammatory response of J774A.1 and THP-1 cells after exposure to particles, measuring subsequent TNFα and IL-6 secretion. Particle composition varied by site and size. Particle constituents were subjected to principal component analysis, identifying three components: C1 (Si, Sr, Mg, Ca, Al, Fe, Mn, endotoxin), C2 (polycyclic aromatic hydrocarbons), and C3 (Zn, S, Sb, Ni, Cu, Pb). Induced TNFα levels were higher and more heterogeneous than IL-6 levels. Cytokines produced by both cell lines only correlated with C1, suggesting that constituents associated with soil induced the inflammatory response and explain observed spatial differences. PMID:23335408

  8. A novel microwave sensor to determine particulate blend composition on-line.

    PubMed

    Austin, John; Gupta, Anshu; McDonnell, Ryan; Reklaitis, Gintaras V; Harris, Michael T

    2014-03-28

    Due to the ease with which particulate blends tend to segregate, blend uniformity and chemical composition are two critical control parameters in nearly all solids manufacturing industries. The prevailing wisdom has been that microwave sensors are not capable of or sensitive enough to measure the relative concentrations of components in a blend. Consequently, it is common to turn to near infrared sensing to determine material composition on-line. In this study, a novel microwave sensor was designed and utilized to determine, separately, the concentrations of different components in a blend of microcrystalline cellulose, acetaminophen, and water. This custom microwave sensor was shown to have comparable accuracy to a commercial NIR probe for both chemical composition and moisture content determination.

  9. Trends In Particulate Organic Carbon Composition In Oregon And California Coast Range Rivers

    NASA Astrophysics Data System (ADS)

    Hatten, J. A.; Goni, M. A.; Wheatcroft, R. A.; Borgeld, J.; Williamson, A.; Padgett, J.; Pasternack, G. B.; Gray, A.; Watson, E.

    2009-12-01

    The discharge of particulate organic carbon (POC) from small mountainous rivers may contribute nearly half of the world’s POC to the ocean. However, these smaller rivers have highly variable discharges throughout the year, which in turn affect the content and composition of POC being delivered to coastal margins. Further, POC composition has been shown to vary by season and throughout specific events. Understanding the composition of POC being discharged under these various conditions yields clues about the material’s stability in the coastal environment, its source within the watershed, and the process of delivery. During the 2008 and 2009 water years, suspended sediment samples were collected from the Alsea, Umpqua, Eel, and Salinas Rivers draining the Coast Ranges of Oregon and California. Events and discharges of various magnitudes were captured in this sample set. Fine (<63 μm) and coarse (>63 μm) particulate material was analyzed for OC, N, δ13C, δ15N, Δ14C, and cupric oxide oxidation products (e.g. lignin, cutin). This poster will present results from these coastal rivers and explore trends in POC in the context of watershed characteristics, discharge, season, and event-scale processes.

  10. Pitch based foam with particulate

    DOEpatents

    Klett, James W.

    2001-01-01

    A thermally conductive, pitch based foam composite having a particulate content. The particulate alters the mechanical characteristics of the foam without severely degrading the foam thermal conductivity. The composite is formed by mixing the particulate with pitch prior to foaming.

  11. Composition and distribution of particulate matter (PM10) in a mechanically ventilated University building

    NASA Astrophysics Data System (ADS)

    Ali, Mohamed Yasreen Mohamed; Hanafiah, Marlia Mohd; Latif, Mohd Talib

    2016-11-01

    This study analyses the composition and distribution of particulate matter (PM10) in the Biology department building, in UKM. PM10 were collected using SENSIDYNE Gillian GilAir-5 Personal Air Sampling System, a low-volume sampler, whereas the concentration of heavy metals was determined using Inductively coupled plasma-mass spectrometry (ICP-MS). The concentration of PM10 recorded in the mechanically ventilated building ranges from 89 µgm-3 to 910 µgm-3. The composition of the selected heavy metals in PM10 were dominated by zinc, followed by copper, lead and cadmium. It was found that the present of indoor-related particulate matter were originated from the poorly maintained ventilation system, the activity of occupants and typical office equipments such as printers and photocopy machines. The haze event occured during sampling periods was also affected the PM10 concentration in the building. This results can serve as a starting point to assess the potential human health damage using the life cycle impact assessment, expressed in term of disability adjusted life year (DALY).

  12. An analytical model for particulate reinforced composites (PRCs) taking account of particle debonding and matrix cracking

    NASA Astrophysics Data System (ADS)

    Jiang, Yunpeng

    2016-10-01

    In this work, a simple micromechanics-based model was developed to describe the overall stress-strain relations of particulate reinforced composites (PRCs), taking into account both particle debonding and matrix cracking damage. Based on the secant homogenization frame, the effective compliance tensor could be firstly given for the perfect composites without any damage. The progressive interface debonding damage is controlled by a Weibull probability function, and then the volume fraction of detached particles is involved in the equivalent compliance tensor to account for the impact of particle debonding. The matrix cracking was introduced in the present model to embody the stress softening stage in the deformation of PRCs. The analytical model was firstly verified by comparing with the corresponding experiment, and then parameter analyses were conducted. This modeling will shed some light on optimizing the microstructures in effectively improving the mechanical behaviors of PRCs.

  13. Developments in the processing and properties of particulate Al-Si composites

    NASA Astrophysics Data System (ADS)

    Ejiofor, J. U.; Reddy, R. G.

    1997-11-01

    In the past ten years, materials R&D has shifted from monolithic to composite materials, adjusting to the global need for reduced weight, low cost, quality, and high performance in structural materials. This article reviews developments in the molten processing of particulate Al-Si alloy composites and their respective properties. Existing and emerging processing innovations are discussed, and the reinforcement phases in prominent R&D activities are identified. The vortex (or mixing) method continues to be the most popular processing method in use because of its ease of operation, total production cost, and suitability, while the infiltration, compocasting (or rheocasting), in-situ, and spray atomization and codeposition techniques receive less attention.

  14. Damage in Particulate Composites with Hard Particles Embedded in a Soft Matrix

    NASA Astrophysics Data System (ADS)

    Kwon, Y.; Liu, C. T.

    1999-04-01

    Damage evolution in a particulate composite around a notch tip was studied. The composite had hard and stiff particles embedded in a soft and weak matrix like a rubber material. The major damage modes were the interface debonding called dewetting and the resulting matrix cracking because the particles were much stronger than the matrix. A numerical modeling and simulation of such damage was conducted using the micro/macro-approach. This technique combined micro-level analysis and macro-level analysis. Damage was described at the micro-level using a damage theory. Damage initiation and growth at a circular notch tip were predicted from the numerical study, and their results were compared with experimental data. Both results compared very well.

  15. Characterization of boron carbide particulate reinforced in situ copper surface composites synthesized using friction stir processing

    SciTech Connect

    Sathiskumar, R.; Murugan, N.; Dinaharan, I.; Vijay, S.J.

    2013-10-15

    Friction stir processing has evolved as a novel solid state technique to fabricate surface composites. The objective of this work is to apply the friction stir processing technique to fabricate boron carbide particulate reinforced copper surface composites and investigate the effect of B{sub 4}C particles and its volume fraction on microstructure and sliding wear behavior of the same. A groove was prepared on 6 mm thick copper plates and packed with B{sub 4}C particles. The dimensions of the groove was varied to result in five different volume fractions of B{sub 4}C particles (0, 6, 12, 18 and 24 vol.%). A single pass friction stir processing was done using a tool rotational speed of 1000 rpm, travel speed of 40 mm/min and an axial force of 10 kN. Metallurgical characterization of the Cu/B{sub 4}C surface composites was carried out using optical microscope and scanning electron microscope. The sliding wear behavior was evaluated using a pin-on-disk apparatus. Results indicated that the B{sub 4}C particles significantly influenced the area, dispersion, grain size, microhardness and sliding wear behavior of the Cu/B{sub 4}C surface composites. When the volume fraction of B{sub 4}C was increased, the wear mode changed from microcutting to abrasive wear and wear debris was found to be finer. Highlights: • Fabrication of Cu/B{sub 4}C surface composite by friction stir processing • Analyzing the effect of B{sub 4}C particles on the properties of Cu/B4C surface composite • Increased volume fraction of B{sub 4}C particles reduced the area of surface composite. • Increased volume fraction of B{sub 4}C particles enhanced the microhardness and wear rate. • B{sub 4}C particles altered the wear mode from microcutting to abrasive.

  16. Al-Ti Particulate Composite: Processing and Studies on Particle Twinning, Microstructure, and Thermal Stability

    NASA Astrophysics Data System (ADS)

    Yadav, Devinder; Bauri, Ranjit; Kauffmann, Alexander; Freudenberger, Jens

    2016-08-01

    The present investigation shows that alternate to the ceramic particles, hard metallic particles can be used as reinforcement in an aluminum matrix to achieve a good strength-ductility combination in a composite. Titanium particles were incorporated into aluminum by friction stir processing (FSP) to process an Al-Ti particulate composite. FSP led to uniform distribution of the particles in the stir zone without any particle-matrix reaction, thereby retaining the particles in their elemental state. Fracture and twinning of the Ti particles with different frequency of occurrence on the advancing and retreating sides of the stir zone was observed. Twinning of the particles was studied by focused ion beam-assisted transmission electron microscopy. The processed Al-Ti composite exhibited a significant improvement in strength and also retained appreciable amount of ductility. The thermal stability of the fine-grained structure against abnormal grain growth (AGG) was improved by the Ti particles. The AGG in the Al-Ti composite occurred at 713 K (440 °C) compared to 673 K (400 °C) in the unreinforced aluminum processed under the same conditions. On the other hand, the particle-matrix reaction occurred only at 823 K (550 °C), and hence the Ti particles were thermally more stable compared to the matrix grain structure.

  17. Chemical compositions of fine particulate organic matter emitted from Chinese cooking.

    PubMed

    Zhao, Yunliang; Hu, Min; Slanina, Sjaak; Zhang, Yuanhang

    2007-01-01

    Food cooking can be a significant source of atmospheric particulate organic matter. In this study, the chemical composition of particulate organic matter (POM) in PM2.5 emitted from four different Chinese cooking styles were examined by gas chromotography-mass spectrometry (GC-MS). The identified species are consistent in the emissions from different Chinese cooking styles and the quantified compounds account for 5-10% of total POM in PM2.5. The dominant homologue is fatty acids, constituting 73-85% of the quantified compounds. The pattern of n-alkanes and the presence of beta-sitosterol and levoglucosan indicate that vegetables are consumed during Chinese cooking operations. Furthermore, the emissions of different compounds are impacted significantly by the cooking ingredients. The candidates of organic tracers used to describe and distinguish emissions from Chinese cooking in Guangzhou are tetradecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, levoglucosan, mannosan, galactosan, nonanal, and lactones. During the sampling period, the relative contribution of Chinese cooking to the mass concentration of atmospheric hexadecanoic acid should be less than 1.3% in Guangzhou.

  18. Natural isotopic composition of nitrogen in suspended particulate matter in the Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Ramesh, R.; Bhosle, N. B.; Sardesai, S.; Sheshshayee, M. S.

    We present the first measurements of nitrogen isotopic composition (δ15N) in suspended particulate matter (SPM) of the surface Bay of Bengal (BOB) at 24 different locations during pre- (April-May 2003) and post- (September-October 2002) monsoon seasons. The δ15N values of particulate organic nitrogen (PON) in surface suspended matter of coastal and northern open BOB show mixing between continental inputs and marine sources. Dilution by continental material brought in by rivers leads to consistently lower δ15N, evident from the relationship between surface salinity and δ15N. δ15N values of surface PON of open ocean locations during both seasons, and also at coastal locations during premonsoon suggest nitrate from deeper waters to be a predominant source of nutrients for phytoplankton. The depth profiles of δ15N of PON during the premonsoon season at nine different locations indicate an increase in δ15N by a maximum of 2.8 between euphotic depth and 300m. These changes are less than those observed in the far eastern Indian Ocean, indicating higher sinking rates of particles ballasted by aggregates of organic and mineral matter in BOB.

  19. Sampling and composition of airborne particulate matter (PM10) from two locations of Mexico City.

    PubMed

    Chirino, Yolanda I; Sánchez-Pérez, Yesennia; Osornio-Vargas, Álvaro Román; Rosas, Irma; García-Cuellar, Claudia María

    2015-09-01

    The PM10 airborne particulate matter with an aerodynamic diameter ≤10 µm is considered as a risk factor of various adverse health outcomes, including lung cancer. Here we described the sampling and composition of PM10 collected from an industrial zone (IZ), and a commercial zone (CZ) of Mexico City. The PM10 was collected with a high-volume sampler in the above mentioned locations and both types of PM10 sampled were characterized by the content of polycyclic aromatic hydrocarbons (PAHs), metals, and endotoxin. The endotoxin PM10 content from IZ and CZ displayed 138.4 UE/mg and 170.4 UE/mg of PM10, respectively.

  20. Comparison of epoxy-based encapsulating materials over temperature and strain rate

    NASA Astrophysics Data System (ADS)

    Khan, Amnah S.; Wilgeroth, James; Balzer, Jens; Proud, William G.

    2017-01-01

    The highly insulating, adhesive and bonding properties of thermosetting epoxies, their ability to be injection moulded in an uncured state, as well as their presence in a wide number of composites, has resulted in their widespread use in both electrical and aerospace applications. There is thus a need to understand the compressive response of epoxies over the range of temperatures likely to be experienced within their working environment. The effects of varying strain rates and temperatures on an epoxy resin (Scotchcast 8) and an epoxy-based syntactic foam (Stycast 1090) were investigated. The samples were studied from -20 °C to +80 °C over a range of strain rates (10-4 - 10+3 s-1). Stress-strain data was obtained, with further analysis from high-speed images. Dynamic Mechanical Analysis (DMA) was also performed on the two materials. Data obtained from these experiments demonstrated key differences in the behaviour of the two materials, forming a basis for comparison with numerical simulations.

  1. Particle size distributions and organic-inorganic compositions of suspended particulate matters around the Bohai Strait

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Bian, Changwei; Bi, Rong; Jiang, Wensheng; Zhang, Hua; Zhang, Xueqing

    2017-02-01

    Laser in situ scattering and transmissometry (LISST) significantly improves our ability to assess particle size distribution (PSD) in seawater, while wide-ranging measurements of the organic-inorganic compositions of suspended particulate matters (SPM) are still difficult by using traditional methods such as microscopy. In this study, PSD properties and SPM compositions around the Bohai Strait (China) were investigated based on the measurements by LISST in combination with hydro-biological parameters collected from a field survey in summer 2014. Four typical PSD shapes were found in the region, namely right-peak, left-peak, double-peak and negative-skew shapes. The double-peak and negative-skew shapes may interconvert into each other along with strong hydrodynamic variation. In the upper layer of the Bohai Sea, organic particles were in the majority, with inorganic particles rarely observed. In the bottom layer, SPM were the mixture of organic and inorganic matters. LISST provided valuable baseline information on size-resolved organic-inorganic compositions of SPM: the size of organic particles mainly ranged from 4 to 20 μm and 40 to 100 μm, while most SPM ranging from 20 to 40 μm were composed of inorganic sediment.

  2. Particulate Titanium Matrix Composites Tested-Show Promise for Space Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Thesken, John C.; Lerch, Bradley A.; Arnold, Steven M.

    2003-01-01

    New manufacturing technologies can now produce uniformly distributed particle strengthened titanium matrix composites (TMCs) at lower cost than many types of continuous-fiber composites. The innovative process results in near-final-shape components having a material stiffness up to 26-percent greater than that of components made with conventional titanium materials. This benefit is achieved with no significant increase in the weight of the component. The improved mechanical performance and low-cost manufacturing capability motivated a review of particulate-reinforced metal composite technology as a way to lower the cost and weight of space-access propulsion systems. Focusing on the elevated-temperature properties of titanium alloy Ti-6Al-4V as the matrix material, researchers at the NASA Glenn Research Center conducted experiments to verify the improved performance of the alloy containing 10 wt% of ceramic titanium carbide (TiC) particles. The appropriate blend of metal and ceramic powder underwent a series of cold and hot isostatic pressing procedures to yield bar stock. A set of round dogbone specimens was manufactured from a small sample of the bars. The TMC material proved to have good machinability at this particle concentration as there was no difficulty in producing high-quality specimens.

  3. DAILY VARIATION IN ORGANIC COMPOSITION OF FINE PARTICULATE MATTER IN THE DETROIT EXPOSURE AND AEROSOL RESEARCH STUDY

    EPA Science Inventory

    Organic composition of fine particulate matter (PM2.5) was investigated as a part of the Detroit Exposure and Aerosol Research Study (DEARS). A high volume (113 liters/minute) sampler was used at the Allen Park community air monitoring station to collect PM2.5 for analysis by ga...

  4. Suspended particulate composition: evolution along a river linear and influence of regime flow

    NASA Astrophysics Data System (ADS)

    Le Meur, Mathieu; Montargès-Pelletier, Emmanuelle; Bauer, Allan; Gley, Renaud; Migot, Sylvie; Mansuy-Huault, Laurence; Lorgeoux, Catherine; Razafitianamaharavo, Angelina; Villièras, Frédéric

    2015-04-01

    Suspended Particulate Matters are recognized to play a crucial role in the transport and fate of chemicals like trace metal elements. The affinity of trace metals with natural SPM is influenced by (i) the nature of metal (ii) physical-chemical conditions of the water column (iii) SPM physical characteristics (grain size, surface area) (iiii) SPM chemical characteristics (elemental composition, mineralogy, organic composition). Some authors observed that the SPM composition was the predominant factor controlling the affinity of trace metals with natural SPM. One purpose of this work is to follow the physical and chemical characteristics of SPM along the river linear in order to better understand the affinity between SPM and heavy metals. One other purpose is to study the influence of regime flow on SPM physical and chemical composition in order to detect any variation of SPM composition with regime flow. SPM were sampled along Moselle river (North East of France) following an urbanization gradient. Two tributaries were also sampled, the Madon river which drains an agricultural catchment and the Fensch stream which flows through an ancient steel-making basin. SPM were sampled several times during high flow and low flow. Particulate matter was extracted on field using continuous flow field centrifuge. Frozen-dried samples were then characterized in terms of size distribution, elemental composition (ICP - AES, ICP - MS), mineralogy (XRD, FTIR, SEM, TEM), surface properties (gas adsorption techniques) and organic composition (Py-GC-MS and GC-MS). Grain size distribution evidenced the presence of coarser particles during high flow but no difference in the grain size distribution could be evidenced between the different stations. The grain size distribution of collected SPM appeared globally identical, although the increase of conductivity due to the junction of Meurthe river . In terms of composition, major element contents in SPM are characterized by the predominance of

  5. Compositional variance in extracted particulate matter using different filter extraction techniques

    NASA Astrophysics Data System (ADS)

    Bein, K. J.; Wexler, A. S.

    2015-04-01

    Collection and subsequent extraction of particulate matter (PM) from filter substrates is a common requirement for in vivo and in vitro toxicological studies, as well as chemical analyses such as ion chromatography and inductively coupled plasma mass spectrometry. Several filter extraction protocols exist and different laboratories employ different methods, potentially biasing inter-study comparisons. Previous studies have shown significant differences in extraction efficiency between techniques and identified the relevant extraction artifacts. However, a comprehensive inter-comparison of different methods based on the chemical composition of the extracted PM has never been conducted. In the current study, an exhaustive suite of chemical analyses is performed on PM extracted from glass micro-fiber filters using techniques commonly employed in different laboratories: Multi-solvent extraction (MSE) and spin-down extraction (SDE). PM samples were collected simultaneously during field studies conducted in an urban and rural setting using a high-volume PM2.5 sampler. Results show remarkable compositional variance between the PM extracts for all chemical components analyzed, including metals, water soluble ions, polycyclic aromatic hydrocarbons, non-aromatic organics, elemental carbon and organic carbon. Mass closure was greater than 90% for MSE but deviated substantially for SDE. Detailed retrospective gravimetric analysis of archived SDE samples revealed that a process-based loss of PM mass is the root cause of the differences. These losses are shown to be compositionally biased, both externally between different PM mixtures and internally within a given PM mixture. In combination, the results of this study are the first to demonstrate (i) an exhaustive chemical characterization of a single PM extract, (ii) the significance of directly characterizing the extracted PM used in toxicological studies, (iii) the existence of substantial compositional biases between

  6. Composition and Integrity of PAHs, Nitro-PAHs, Hopanes and Steranes In Diesel Exhaust Particulate Matter

    PubMed Central

    Huang, Lei; Bohac, Stanislav V.; Chernyak, Sergei M.; Batterman, Stuart A.

    2013-01-01

    Diesel exhaust particulate matter contains many semivolatile organic compounds (SVOCs) of environmental and health significance. This study investigates the composition, emission rates, and integrity of 25 SVOCs, including polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and diesel biomarkers hopanes and steranes. Diesel engine particulate matter (PM), generated using an engine test bench, three engine conditions, and ultra-low sulfur diesel (ULSD), was collected on borosilicate glass fiber filters. Under high engine load, the PM emission rate was 0.102 g/kWh, and emission rate of ΣPAHs (10 compounds), ΣNPAHs (6 compounds), Σhopanes (2 compounds), and Σsteranes (2 compounds) were 2.52, 0.351, 0.02 ~ 2 and 1μg/kWh, respectively. Storage losses were evaluated for three cases: conditioning filters in clean air at 25 °C and 33% relative humidity (RH) for 24 h; storing filter samples (without extraction) wrapped in aluminum foil at 4 °C for up to one month; and storing filter extracts in glass vials capped with Teflon crimp seals at 4 °C for up to six months. After conditioning filters for 24 h, 30% of the more volatile PAHs were lost, but lower volatility NPAHs, hopanes and steranes showed negligible changes. Storing wrapped filters and extracts at 4 °C for up to one month did not lead to significant losses, but storing extracts for five months led to significant losses of PAHs and NPAHs; hopanes and steranes demonstrated greater integrity. These results suggest that even relatively brief filter conditioning periods, needed for gravimetric measurements of PM mass, and extended storage of filter extracts can lead to underestimates of SVOC concentrations. Thus, SVOC sampling and analysis protocols should utilize stringent criteria and performance checks to identify and limit possible biases occurring during filter and extract processing. PMID:24363468

  7. Corrosive wear of SiC whisker- and particulate-reinforced 6061 aluminum alloy composites

    SciTech Connect

    Yu, S.Y.; Ishii, H.; Chuang, T.H.

    1996-09-01

    Wear tests on SiC whisker- and SiC particulate-reinforced 6061-T6 aluminum matrix composites (SiCw/Al and SiCp/Al), fabricated using a high pressure infiltration method, were performed in laboratory air, ion-exchanged water and a 3 pct NaCl aqueous solution using a block-on-ring type apparatus. The effects of environment, applied load, and rotational (sliding) speed on the wear properties against a sintered alumina block were evaluated. Electrochemical measurements in ion-exchanged water and a 3 pct NaCl aqueous solution were also made under the same conditions as the wear tests. A comparison was made with the properties of the matrix aluminum alloy 6061-T6. The SiC-reinforced composites exhibited better wear resistance compared with the monolithic 6061 Al alloy even in a 3 pct NaCl aqueous solution. Increase in the wear resistance depended on the shape, size, and volume fraction of the SiC reinforcement. Good correlation was obtained between corrosion resistance and corrosion wear. The ratios of wear volume due to the corrosive effect to noncorrosive wear were 23 to 83 pct, depending on the wear conditions.

  8. Composites of low-density trialuminides: Particulate and long fiber reinforcements

    NASA Technical Reports Server (NTRS)

    Kumar, K. S.; Dipietro, M. S.; Brown, S. A.; Whittenberger, J. D.

    1992-01-01

    An examination of the ternary L1(sub 2) trialuminides, Al66Ti25Mn9, Al67Ti25Cr8, and Al22Ti8Fe3 in compression, bending, and tension revealed that none of these compounds exhibited a desirable balance of strength, ductility, and oxidation resistance. Subsequently, specific quaternary and quinary compositions were cast, homogenized, and isothermally forged. Both, the monolithic material and its particulate reinforced counterparts were examined in compression, three point bend, and tension as a function of temperature, and at high temperatures as a function of strain rate. An alternate approach that was examined in this program to enhance the low temperature damage tolerance of these materials was to incorporate long refractory metal wires in the matrix. In summary, it appears that of the various matrix compositions examined, ternary Al66Ti25Mn9 exhibits the best balance in strength, ductility, and oxidation resistance. Although the idea of refractory metal wire reinforcement is an attractive one, a successful combination remains to be identified.

  9. Physical, Mechanical and Water Absorption Behaviour of Coir Fiber Reinforced Epoxy Composites Filled With Al2O3 Particulates

    NASA Astrophysics Data System (ADS)

    Das, Geetanjali; Biswas, Sandhayarani

    2016-02-01

    The objective of the present work is to study the physical, mechanical and water absorption behaviour of coir fiber reinforced epoxy composites filled with Al2O3 particulates. Composites with different compositions were prepared by varying the length of the fiber and content of fiber using hand lay-up technique. The experimental investigation reveals that the properties of composite increases with the incorporation of Al2O3 particulates. It is observed that the density of composites increases with increase in fiber content, while a decrease in density is observed with increase in fiber length. The strength properties of the composites increases with the increase in fiber content up to 15 wt.% and 12mm fiber length, however further increase in fiber length and fiber content the value decreases. The maximum tensile strength of 25.71MPa, flexural strength of 29.75MPa and impact strength of 14.76kJ/m2 is obtained for composites with 12 mm fiber length and 15 wt.% of fiber content. The hardness and tensile modulus, on the other hand, increases with increase in fiber length and fiber content. The maximum hardness value of 19.52Hv and tensile modulus of 3.412GPa is obtained for composites with 15mm fiber length and 20 wt.% of fiber content. Finally, morphological analysis is also carried out using scanning electron microscope (SEM) to study the fracture behaviour of the composite samples.

  10. Simulating the effects of light intensity and carbonate system composition on particulate organic and inorganic carbon production in Emiliania huxleyi.

    PubMed

    Holtz, Lena-Maria; Wolf-Gladrow, Dieter; Thoms, Silke

    2015-05-07

    Coccolithophores play an important role in the marine carbon cycle. Variations in light intensity and external carbonate system composition alter intracellular carbon fluxes and therewith the production rates of particulate organic and inorganic carbon. Aiming to find a mechanistic explanation for the interrelation between dissolved inorganic carbon fluxes and particulate carbon production rates, we develop a numerical cell model for Emiliania huxleyi, one of the most abundant coccolithophore species. The model consists of four cellular compartments, for each of which the carbonate system is resolved dynamically. The compartments are connected to each other and to the external medium via substrate fluxes across the compartment-confining membranes. By means of the model we are able to explain several pattern observed in particulate organic and inorganic carbon production rates for different strains and under different acclimation conditions. Particulate organic and inorganic carbon production rates for instance decrease at very low external CO2 concentrations. Our model suggests that this effect is caused mainly by reduced HCO3(-) uptake rates, not by CO2 limitation. The often observed decrease in particulate inorganic carbon production rates under Ocean Acidification is explained by a downregulation of cellular HCO3(-) uptake.

  11. Processing and response of aluminum-lithium alloy composites reinforced with copper-coated silicon carbide particulates

    NASA Astrophysics Data System (ADS)

    Khor, K. A.; Cao, Y.; Boey, F. Y. C.; Hanada, K.; Murakoshi, Y.; Sudarshan, T. S.; Srivatsan, T. S.

    1998-02-01

    Lithium-containing aluminum alloys have shown promise for demanding aerospace applications because of their light weight, high strength, and good damage tolerance characteristics. Additions of ceramic reinforcements to an aluminum-lithium alloy can significantly enhance specific strength, and specific modulus while concurrently offering acceptable performance at elevated temperatures. The processing and fabrication of aluminum-lithium alloy-based composites are hampered by particulate agglomeration or clustering and the existence of poor interfacial relationships between the reinforcing phase and the matrix. The problem of distribution of the reinforcing phase in the metal matrix can be alleviated by mechanical alloying. This article presents the results of a study aimed at addressing and improving the interfacial relationship between the host matrix and the reinforcing phase. Copper-coated silicon carbide particulates are introduced as the particulate reinforcing phase, and the resultant composite mixture is processed by conventional milling followed by hot pressing and hot extrusion. The influence of extrusion ratio and extrusion temperature on microstructure and mechanical properties was established. Post extrusion processing by hot isostatic pressing was also examined. Results reveal the increase in elastic modulus of the aluminum-lithium alloy matrix reinforced with copper-coated SiC to be significantly more than the mechanically alloyed Al-Li/SiC counterpart. This suggests the possible contributions of interfacial strengthening on mechanical response in direct comparison with a uniform distribution of the reinforcing ceramic particulates.

  12. Composition and flux of particulate amino acids and chloropigments in equatorial Pacific seawater and sediments

    NASA Astrophysics Data System (ADS)

    Lee, Cindy; Wakeham, Stuart G.; Hedges, John I.

    2000-08-01

    Compositions and fluxes of amino acids and major chloropigments were measured in the central equatorial Pacific Ocean as part of the US JGOFS EqPac program. Fluxes decreased by several orders of magnitude, from 400 to 0.03 mg amino acid m -2 d -1 and from 9 mg to 0.0004 μg chloropigment m -2 d -1, between production in the surface waters and accumulation at the sea floor. Most rapid losses were in surface waters and at the sediment interface. Losses from the mid-water column were as great as those in surface waters or at the sediment interface, but occurred over a much greater depth range. Export flux estimates based on floating sediment traps were higher near the equator and decreased poleward, similar to primary production. Little meridional difference was apparent in composition of either amino acids or pigments in exported material over the 24° of latitude sampled in spite of the large (factor of 5-6) difference in fluxes. However, pigment composition changed dramatically with depth in the water column, and considerable diagenesis occurred before particles reached the sediment. Pigment compositions suggest that suspended particles were more degraded in the northern than in the southern hemisphere, possibly due to differences in food chain structure. Compositional changes in amino acids occurred in the water column, but were most noticeable at the sediment-seawater interface. Increases in the relative proportions of aspartic acid and glycine with depth were more consistent with preferential preservation within the particulate matrix than with any inherent stability of these compounds to heterotrophic consumption. The contribution of amino acids and pigments to total organic carbon clearly shows that selective degradation of organic matter occurs with depth; this is not evident from total organic carbon data alone. Amino acids contributed about a quarter of the total organic carbon (OC) in surface waters and 16% of the OC in sediment; pigments decreased from 1

  13. Effect of microstructure (particulate size and volume fraction) and counterface material on the sliding wear resistance of particulate-reinforced aluminum matrix composites

    NASA Astrophysics Data System (ADS)

    Alpas, A. T.; Zhang, J.

    1994-05-01

    The effects of microstructure (namely, particulate volume fraction and particulate size) and the counterface materials on the dry-sliding wear resistance of the aluminum matrix composites 2014A1-SiC and 6061Al-Al2O3 were studied. Experiments were performed within a load range of 0.9 to 350 N at a constant sliding velocity of 0.2 ms-1. Two types of counterface materials, SAE 52100 bearing steel and mullite, were used. At low loads, where particles act as loadbearing constituents, the wear resistance of the 2014A1 reinforced with 15.8 µm diameter SiC was superior to that of the alloy with the same volume fraction of SiC but with 2.4 µm diameter. The wear rates of the composites worn against a steel slider were lower compared with those worn against a mullite slider because of the formation of iron-rich layers that act as in situ solid lubricants in the former case. With increasing the applied load, SiC and A12O3 particles fractured and the wear rates of the composites increased to levels comparable to those of unreinforced matrix alloys. The transition to this regime was delayed to higher loads in the composites with a higher volume percentage of particles. Concurrent with particle fracture, large strains and strain gradients were generated within the aluminum layers adjacent to contact surfaces. This led to the subsurface crack growth and delamination. Because the particles and interfaces provided preferential sites for subsurface crack initiation and growth and because of the propensity of the broken particles to act as third-body abrasive elements at the contact surfaces, no improvement of the wear resistance was observed in the composites in this regime relative to unreinforced aluminum alloys. A second transition, to severe wear, occurred at higher loads when the contact surface temperature exceeded a critical value. The transition loads (and temperatures) were higher in the composites. The alloys with higher volume fraction of reinforcement provided better

  14. Compressive evaluation of homogeneous and graded epoxy-glass particulate composites.

    PubMed

    Seaglar, J; Rousseau, C-E

    2015-04-01

    The propagation of stress waves in epoxy-glass particulate composites and graded materials was studied experimentally. Materials tested in this study consisted of an epoxy matrix with various concentrations of spherical glass particles having a mean diameter of 42μm. Plate impact experiments were performed using a gas gun. Embedded within the specimens were manganin stress gauges used to record propagating compressive longitudinal stress waves through the material. High strain rate experiments using a Split Hopkinson Pressure Bar (SHPB) apparatus were also performed to evaluate the dynamic strength of the specimens, while quasi-static compression tests were undertaken to characterize their quasi-static behavior. Ultrasonic wave speed measurements were carried-out in order to obtain additional material properties and characterize the gradation in functionally graded materials (FGM). It was found that low volume fractions of particles are detrimental to the performance of the material under impact loading, while concentrations in the range of about 30 to 45% by volume exhibit characteristics of higher degrees of scattering. This suggests that materials in this latter range would be more effective in the thwarting of destructive shock waves than the homogeneous matrix material. Impact testing of FGM specimens suggests that impact loading on the stiff (high volume fraction) face results in much higher levels of scattering. Therefore, such materials would be effective for use in light weight armor or as shielding materials due to their effective attenuation of mechanical impulses.

  15. Fractionation and composition of colloidal and suspended particulate materials in rivers.

    PubMed

    Ran, Y; Fu, J M; Sheng, G Y; Beckett, R; Hart, B T

    2000-07-01

    The association of pollutants (nutrients, heavy metals and organic compounds) with colloidal and suspended particle matter (SPM) plays a dominant role in determining their transport, fate, biogeochemistry, bioavailability and toxicity in natural waters. A scheme for the fractionation and composition of colloidal and SPM from river waters has been tested. All four separation methods, i.e. sieving, continuous flow centrifugation, tangential flow filtration, sedimentation field-flow fractionation, were for the first time used to separate five size particulate fractions from river. Significant (gram) amounts of colloidal material (<1 microm) in three size ranges, nominally 1-0.2, 0.2-0.006 and 0.006-0.003 microm were obtained. The separation scheme was able to process large samples (100 l), within reasonable times (1 day) and the apparatus was portable. The aquatic colloid size was also characterized with high resolution by using sedimentation field-flow fractionation technique. The mass-based particle size distribution for the water sample showed a broad size distribution between 0.05 and 0.4 microm with the maximum around 0.14 microm. There was a systematic increase in the content of organic carbon (estimated by loss on ignition), Mg, Ca, Na, Cu and Zn with decreasing particle size, highlighting the importance of the colloidal (<1 microm) fraction. It was concluded that the colloidal Cu and Zn concentrations in rivers might be much higher than those reported before.

  16. Studies on in situ particulate reinforced tin-silver composite solders relevant to thermomechanical fatigue issues

    NASA Astrophysics Data System (ADS)

    Choi, Sunglak

    2001-07-01

    Global pressure based on environmental and health concerns regarding the use of Pb-bearing solder has forced the electronics industry to develop Pb-free alternative solders. Eutectic Sn-Ag solder has received much attention as a potential Pb-free candidate to replace Sn-Pb solder. Since introduction of surface mount technology, packaging density increased and the electronic devices became smaller. As a result, solders in electronic modules are forced to function as a mechanical connection as well as electrical contact. Solders are also exposed to very harsh service conditions such as automotive under-the-hood and aerospace applications. Solder joints experience thermomechanical fatigue, i.e. interaction of fatigue and creep, during thermal cycling due to temperature fluctuation in service conditions. Microstructural study on thermomechanical fatigue of the actual eutectic Sn-Ag and Sn-4Ag-0.5Cu solder joints was performed to better understand deformation and damage accumulation occurring during service. Incorporation of reinforcements has been pursued to improve the mechanical and particularly thermomechanical behavior of solders, and their service temperature capability. In-situ Sn-Ag composite solders were developed by incorporating Cu 6Sn5, Ni3Sn4, and FeSn2 particulate reinforcements in the eutectic Sn-Ag solder in an effort to enhance thermomechanical fatigue resistance. In-situ composite solders were investigated on the growth of interfacial intermetallic layer between solder and Cu substrate growth and creep properties. Solder joints exhibited significant deformation and damage on free surface and interior regions during thermomechanical fatigue. Cracks initiated on the free surface of the solder joints and propagated toward interior regions near the substrate of the solder joint. Crack grew along Sn grain boundaries by grain boundary sliding. There was significant residual stress within the solder joint causing more damage. Presence of small amount of Cu

  17. Composition of particulate and dissolved organic matter in a disturbed watershed of southeast Brazil (Piracicaba River basin).

    PubMed

    Krusche, Alex V; Martinelli, Luiz A; Victoria, Reynaldo L; Bernardes, Marcelo; de Camargo, Plinio B; Ballester, Maria V; Trumbore, Susan E

    2002-06-01

    The elemental and isotopic composition of particulate and dissolved organic matter was investigated in the Piracicaba River basin, São Paulo State, Brazil. Comparison of riverine organic matter from the Piracicaba River basin, a region where rivers and streams receive urban sewage and industrial effluents, with data reported for the pristine Amazon system revealed significant differences associated with anthropogenic impacts. One important difference was N enrichment in the particulate organic material of the Piracicaba basin rivers, due to (a) urban and industrial effluents, and (b) enhanced phytoplankton growth, which results from the combination of nutrient enrichment and damming of sections of the rivers. Radiocarbon concentrations were overall more depleted (older 14C age) in the Piracicaba basin rivers than in the Amazon, which may reflect the importance of soil erosion in the former. Analyses of stable and radioactive carbon isotopes and lignin-derived compounds indicated that coarse particulate organic material is composed of a mixture of soil particles and degraded organic matter from C3 and C4 vascular plants. Fine particulate organic material was composed mainly of soil particles and phytoplankton cell remains, the latter especially during low water. Ultrafiltered dissolved organic matter was the most degraded fraction according to its lignin oxidation products, and showed the greatest influence of C4 plant sources.

  18. Particulate Titanium Matrix Composites Tested--Show Promise for Space Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley A.; Ellis, J. Rodney; Arnold. Steven M.

    2004-01-01

    Uniformly distributed particle-strengthened titanium matrix composites (TMCs) can be manufactured at lower cost than many types of continuous-fiber composites. The innovative manufacturing technology combines cold and hot isostatic pressing procedures to produce near-final-shape components. Material stiffness is increased up to 26-percent greater than that of components made with conventional titanium materials at no significant increase in the weight. The improved mechanical performance and low-cost manufacturing capability motivated an independent review to assess the improved properties of ceramic titanium carbide (TiC) particulate-reinforced titanium at elevated temperature. Researchers at the NASA Glenn Research Center creatively designed and executed deformation and durability tests to reveal operating regimes where these materials could lower the cost and weight of space propulsion systems. The program compares the elevated-temperature performance of titanium alloy Ti-6Al-4V matrix material to an alloy containing 10 wt% of TiC particles. Initial experiments showed that at these relatively low particle concentrations the material stiffness of the TMC was improved 20 percent over that of the plain Ti-6Al-4V alloy when tested at 427 C. The proportional limit and ultimate strength of the composite in tension are 21- and 14-percent greater than those of the plain alloy. Compression tests showed that the proportional limit is about 30 percent greater for TMC than for the plain alloy. The enhanced deformation resistance of the TMC was also evident in a series of tensile and compressive stress relaxation tests that were made. Specimens were subjected to tensile or compressive strain amplitudes of 0.75 percent for 24 hr followed by a return to zero strain imposed for 24 hr. The stress relaxation data were normalized with respect to the maximum stress for each case and plotted as a function of time in the following graph. Tensile stresses relaxed 19 percent for the

  19. Applicability of ultrasonic testing for the determination of volume fraction of particulates in alumina-reinforced aluminum matrix composites

    SciTech Connect

    Fang, C.K.; Fang, R.L.; Weng, W.P.; Chuang, T.H.

    1999-10-01

    An ultrasonic testing technique was employed to determine the volume fraction of alumina particulate reinforcement in 6061 aluminum matrix composites. this study was performed on various composites with Al{sub 2}O{sub 3} nominal volume fractions of 10, 15, and 20%. For comparison, other techniques were employed as well, including the Archimedes method, metallographic image analysis, X-ray diffraction, and acid dissolution. Observations indicated that ultrasonic testing and acid dissolution methods are more reliable than the other techniques, while ultrasonic testing is faster than the acid dissolution method.

  20. Diurnal trends in coarse particulate matter composition in the Los Angeles Basin.

    PubMed

    Cheung, Kalam; Daher, Nancy; Shafer, Martin M; Ning, Zhi; Schauer, James J; Sioutas, Constantinos

    2011-11-01

    To investigate the diurnal profile of the concentration and composition of ambient coarse particles, three sampling sites were set up in the Los Angeles Basin to collect coarse particulate matter (CPM) in four different time periods of the day (morning, midday, afternoon and overnight) in summer and winter. The samples were analyzed for total and water-soluble elements, inorganic ions and water-soluble organic carbon (WSOC). In summer, highest concentrations of CPM gravimetric mass, mineral and road dust, and WSOC were observed in midday and afternoon, when the prevailing onshore wind was stronger. In general, atmospheric dilution was lower in winter, contributing to the accumulation of air pollutants during stagnation conditions. Turbulences induced by traffic become a significant particle re-suspension mechanism, particularly during winter night time, when mixing height was lowest. This is evident by the high levels of CPM mass, mineral and road dust in winter overnight at the near-freeway sites located in urban Los Angeles, and to a lesser extent in Riverside. WSOC levels were higher in summer, with a similar diurnal profile with mineral and road dust, indicating that they either share common sources, or that WSOC may be adsorbed or absorbed onto the surfaces of these dust particles. In general, the contribution of inorganic ions to CPM mass was greater in the overnight sampling period at all sampling sites, suggesting that the prevailing meteorological conditions (lower temperature and higher relative humidity) favor the formation of these ions in the coarse mode. Nitrate, the most abundant CPM-bound inorganic species in this basin, is found to be predominantly formed by reactions with sea salt particles in summer. When the sea salt concentrations were low, the reaction with mineral dust particles and the condensation of ammonium nitrate on CPM surfaces also contributes to the formation of nitrate in the coarse mode.

  1. Composition and size distribution of airborne particulate PAHs and oxygenated PAHs in two Chinese megacities

    NASA Astrophysics Data System (ADS)

    Ren, Yanqin; Zhou, Bianhong; Tao, Jun; Cao, Junji; Zhang, Zhisheng; Wu, Can; Wang, Jiayuan; Li, Jianjun; Zhang, Lu; Han, Yanni; Liu, Lang; Cao, Cong; Wang, Gehui

    2017-01-01

    Concentrations and compositions of PAHs and oxygenated PAHs (OPAHs) in four size ranges of ambient particles (< 1.1, 1.1-3.3, 3.3-9.0 and > 9.0 μm) collected in Xi'an and Guangzhou, two megacities of China, during the winter and summer of 2013 were measured and compared with those in 2003. The TSP-equivalent concentrations of Σ14PAHs in Xi'an and Guangzhou are 57 ± 20 and 18 ± 23 ng m- 3 in winter, 5-10 times higher than those in summer. PAHs in both cities are dominated by 5- and 6-ring congeners in summer. In contrast, they are dominated by 4- and 5-ring congeners in winter, probably due to enhanced gas-to-particle phase partitioning of the semi-volatile PAHs. TSP-equivalent Σ7OPAHs during winter are 54 ± 15 and 23 ± 32 ng m- 3 in Xi'an and Guangzhou and dominated by 5-ring OPAHs. Size distribution results showed that the fine modes (< 3.3 μm) of PAHs and OPAHs in both cities are dominated by 4- and 5-ring congeners in winter and 5- and 6-ring congeners in summer. Relative abundances of 3-ring PAHs and OPAHs increased along with an increase in particle sizes, accounting for from about 1% of the total PAHs or OPAHs in the smallest particles (< 1.1 μm) to > 90% of the total in the largest particles (> 9.0 μm). The toxicity of PAH assessment indicated that atmospheric particles in Xi'an and Guangzhou during winter are much more toxic than those during summer and fine particles are more toxic than coarse particles. Compared to those in 2003, fine particulate PAHs and OPAHs in both cities during winter decreased by 50-90%, most likely due to the replacement of coal by natural gas in the country.

  2. Particulate matter concentration and chemical composition in the metro system of Rome, Italy.

    PubMed

    Perrino, C; Marcovecchio, F; Tofful, L; Canepari, S

    2015-06-01

    Air quality at the main station of the metro system of Rome (Termini hub) has been characterized by the point of view of particulate matter (PM) concentration and chemical composition. Indoor air in different environments (underground train platform and shopping center, metro carriages with and without air conditioning system) has been studied and compared with outdoor air at a nearby urban site. Air quality at the railway station, located outdoor at surface level, has been also considered for comparison. PM chemical characterization included ions, elemental carbon, organic carbon, macro-elements, and the bio-accessible and residual fractions of micro- and trace elements. Train platform and carriages without air conditioning resulted to be the most polluted environments, with indoor/outdoor ratio up to two orders of magnitude for many components. PM mass concentration was determined on filter membranes by the gravimetric procedure as well as from the optical particle counter (OPC) number concentration measurements. The OPC results, taken with the original calibration factor, were below 40 % of the value obtained by the gravimetric measurements. Only a chemical and morphological characterization of the collected dust could lead to a reconciliation of the results yielded by the two methods. Macro-components were used to estimate the strength of the main macro-sources. The most significant contribution is confirmed to derive from wheels, rails, and brakes abrasion; from soil re-suspension (over 50 % at the subway platform); and from organics (about 25 %). The increase in the concentration of elements was mostly due to the residual fraction, but also the bio-accessible fraction showed a remarkable enrichment, particularly in the case of Ba, Zn, Cd, and Ni.

  3. Size-segregated composition of particulate matter (PM) in major roadways and surface streets

    NASA Astrophysics Data System (ADS)

    Kam, W.; Liacos, J. W.; Schauer, J. J.; Delfino, R. J.; Sioutas, C.

    2012-08-01

    A sampling campaign was conducted to assess on-road particulate matter (PM) composition for three size fractions (PM10-2.5, PM2.5-0.25, and PM0.25) on three representative roadways in Los Angeles: 1) the I-110, a high-traffic freeway composed mostly of light-duty vehicles (LDVs), 2) the I-710, a major freeway for heavy-duty vehicles (HDVs) traveling to and from the Ports of Los Angeles and Long Beach, and 3) Wilshire/Sunset Blvd, two major surface streets. Concurrent sampling was conducted at the University of Southern California (USC), which was used as an urban background site. Two sets of PM samples were collected for each roadway, with a sampling duration of approximately 50 h for each set. The samples were analyzed for inorganic ions, elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC), and trace elements and metals. Results showed that the PM0.25 fraction is heavily influenced by on-road vehicular emissions, as indicated by average roadway PM concentrations that were 48.0 ± 9.4% higher than those observed at USC (p < 0.05), while the PM10-2.5 fraction is mostly influenced by resuspension of road dust and the PM2.5-0.25 fraction is mainly composed of secondary species. Overall, the composition of inorganic ions (%) was relatively consistent across the three roadway environments. With very low EC levels in PM10-2.5, the most notable difference among the three roadway environments was the PM2.5 EC levels observed on the I-710, which are 2.0 ± 0.2 μg m-3 and 4.1 times greater than USC, while levels on the I-110 and Wilshire/Sunset were 1.0 ± 0.2 μg m-3 and 0.6 ± 0.01 μg m-3 and 2.1 and 1.2 times greater, respectively. PM2.5 OC and WSOC concentrations were observed to be 1.6, 2.0, and 1.7 times greater on the I-110, I-710, and Wilshire/Sunset than corresponding levels at USC, respectively. Results from this study may have major public health implications for passengers who commute frequently on high-traffic roadways. Finally, a comparison of

  4. Meso-damage modelling of polymer based particulate composites using finite element technique

    NASA Astrophysics Data System (ADS)

    Tsui, Chi Pong

    To develop a new particulate polymer composite (PPC) with desired mechanical properties is usually accomplished by an experimental trial-and-error approach. A new technique, which predicts the damage mechanism and its effects on the mechanical properties of PPC, has been proposed. This meso-mechanical modelling technique, which offers a means to bridge the micro-damage mechanism and the macro-structural behaviour, has been implemented in a finite element code. A three-dimensional finite element meso-cell model has been designed and constructed to simulate the damage mechanism of PPC. The meso-cell model consists of a micro-particle, an interface, and a matrix. The initiation of the particle/polymer matrix debonding process has been predicted on the basis of a tensile criterion. By considering the meso-cell model as a representative volume element (RVE), the effects of damage on the macro-structural constitutive behaviour of PPC have been determined. An experimental investigation has been made on glass beads (GB) reinforced polyphenylene oxides (PPO) for verification of the meso-cell model and the meso-mechanical finite element technique. The predicted constitutive relation has been found to be in good agreement with the experimental results. The results of the in-situ microscopic test also verify the correctness of the meso-cell model. The application of the meso-mechanical finite element modelling technique has been extended to a macro-structural analysis to simulate the response an engineering structure made of PPC under a static load. In the simulation, a damage variable has been defined in terms of the computational results of the cell model in meso-scale. Hence, the damage-coupled constitutive relation of the GB/PPO composite could be derived. A user-defined subroutine VUMAT in FORTRAN language describing the damage-coupled constitutive behaviour has then been incorporated into the ABAQUS finite element code. On a macro-scale, the ABAQUS finite element code

  5. Healing efficiency of epoxy-based materials for structural application

    NASA Astrophysics Data System (ADS)

    Raimondo, Marialuigia; Guadagno, Liberata

    2012-07-01

    This paper describes a self-healing composite exhibiting high levels of healing efficiency under working conditions typical of aeronautic applications. The self-healing material is composed of a thermosetting epoxy matrix in which a catalyst of Ring Opening Metathesis Polymerization (ROMP) and nanocapsules are dispersed. The nanocapsules contain a monomer able to polymerize via ROMP. The preliminary results demonstrate an efficient self-repair function which is also active at very low temperatures.

  6. Synthesis and Characterization of In Situ Dendritic/Particulate α-Al(Fe,TM)Si Phase Reinforced Al Matrix Composites

    NASA Astrophysics Data System (ADS)

    Hou, L. G.; Wang, Shuai; He, Z. B.; Zhang, D.; Wang, X. D.; Zhuang, L. Z.; Zhang, J. S.

    2016-12-01

    The strength and ductility of transition metallic element alloyed Al alloys could be inevitably and severely weakened if these elements appeared as coarse intermetallics. Present studies aimed to optimize the morphologies and sizes of these intermetallics via composition design and process selection so as to decrease their detrimental effects to the properties. It is shown that the dendritic α-Al(Fe,TM)Si phase solidified as primary phase can be refined into small dendrites or micro- and submicro-sized particles via controlling the cooling rate and alloy composition, and this phase exhibits better heat resistance. After spark plasma sintering (SPS) the atomized alloy powders, the bulk aluminum matrix composites (AMCs) were successfully prepared and well strengthened by the uniformly distributed particulate α-Al(Fe,TM)Si phase. These sintered bulk composites also possess good heat resistance that might facilitate their application for some heat-resistant parts. The transmission electron microscope (TEM) and high-resolution TEM (HRTEM) results indicate these α-Al(Fe,TM)Si phases possesses body-centered-cubic structure with a lattice constant of 1.25 to 1.27 nm. The solidification or phase formation of these alloys is discussed as well as the densification process for the SPS of powders. The present studies indicate a possibility to prepare in situ small dendritic/particulate α-Al(Fe,TM)Si phase reinforced AMCs by using the casting process and controlling the normal impurity elements in Al alloys.

  7. Chemical composition and size distribution of airborne particulate matters in Beijing during the 2008 Olympics

    NASA Astrophysics Data System (ADS)

    Li, Xingru; Wang, Lili; Wang, Yuesi; Wen, Tianxue; Yang, Yongjie; Zhao, Yanan; Wang, Yingfeng

    2012-04-01

    Size-segregated aerosol samples were collected daily in Beijing from 1 Jun. to 20 Sep. during the Beijing Olympic Games in 2008 to investigate aerosol concentrations, particle size distributions, and sources as well as the effects of pollution control measures on the chemical compositions (including Water-soluble ions, trace elements, elemental carbon (EC), and organic carbon (OC)) in aerosols of different sizes. Water-soluble ions, EC, OC, and trace elements accounted for 45.0%, 1.6%, 14.7%, and 11.4% of the total particle mass (PM), respectively. Approximately 56%, 56%, 30%, 71% and 55% of the PM, water-soluble ions, trace elements, EC and OC, respectively, were associated with particles smaller than 2.1 μm. Sulfate, nitrate, and ammonium were the dominant ions, which together accounted for approximately 77% of total water-soluble ions. The crustal elements accounted for the majority of the trace elements present. Different sources showed different mass size distributions. Anthropogenic source compounds, such as sulfate, nitrate, ammonium, OC, EC, and toxic elements, were mainly present in fine mode aerosols, whereas crustal elements, such as Al, Fe, Ca, Mg and Ba, primarily occurred in the coarse mode. SO42- and NH4+ concentrations were strongly correlated (r2 = 0.90, slope = 1.63) in the fine mode, thereby indicating that SO42- was mainly present as (NH4)2SO4; in contrast, a weak correlation between SO42- and NH4+ (r2 = 0.18, slope = 0.54) was observed in the coarse mode, indicating that SO42- was associated with other ions. Similarly, SO42- and NO3- exhibited a stronger correlation in the fine mode than in the coarse mode, indicating that SO42- and NO3- were formed via the same in-cloud processes in fine particles. The OC/EC ratio and the correlations between EC and OC concentrations showed that the sources of carbonaceous species were secondary organic carbon from fine particles and the long-range transport of coarse carbonaceous particles from biomass

  8. Characteristics and chemical compositions of particulate matter collected at the selected metro stations of Shanghai, China.

    PubMed

    Guo, Li; Hu, Yunjie; Hu, Qingqing; Lin, Jun; Li, Chunlin; Chen, Jianmin; Li, Lina; Fu, Hongbo

    2014-10-15

    A campaign was conducted to assess and compare the air quality at the different metro platforms at Shanghai City, focusing on particulate matter (PM) levels, chemical compositions, morphology and mineralogy, as well as species of iron. Our results indicated that the average PM₂.₅ concentrations for the three metro lines were 177.7 μg/m(3), 105.7 μg/m(3) and 82.5 μg/m(3), respectively, and the average PM1 concentrations for the three lines were 122.3 μg/m(3), 84.1 μg/m(3) and 59.6 μg/m(3), respectively. Fe, Mn, Cr, Cu, Sr, Ba and Pb concentrations in all of the sampling sites were significantly higher than that in the urban ambient air, implicating that these trace metals may be associated with the metro systems working. Individual airborne dusts were studied for morphology and mineralogy characteristics. The results revealed that the presence of most individual particles were with no definite shape and most of them were with a large metal content. Furthermore, Fe-rich particles had significantly higher abundance in the metro systems, which were more frequently encountered in the underground lines than the aboveground line. The 2D distribution map of an interested Fe-rich particle showed an uneven Fe distribution, implying that a hollow or core of other substance exists in the particle center during the formation process. Cluster analysis revealed that Fe-rich particles were possibly a mixture of Fe species. Fitting of X-ray absorption near-edge fine structure spectra (XANES) showed the main iron species within the particles collected from the three contrasting metro lines of Shanghai to be hematite, magnetite, iron-metal and mineral Fe. Hematite and mineral Fe were all found in three lines, while magnetite only existed in aboveground metro line. Iron-metal was determined in both the older and younger underground lines, based on the X-ray diffraction (XRD) analysis. As diverse Fe species have different physical-chemical characteristics and toxicity, the

  9. Spatial distribution of summertime particulate matter and its composition in Greece

    NASA Astrophysics Data System (ADS)

    Tsiflikiotou, Maria; Papanastasiou, Dimitris; Zarmpas, Paulos; Paraskevopoulou, Despoina; Diapouli, Evangelia; Kostenidou, Evangelia; Kaltsonoudis, Christos; Bougiatioti, Aikaterini; Theodosi, Christina; Kouvarakis, George; Liakakou, Eleni; Vassilatou, Vassiliki; Siakavaras, Dimitris; Biskos, George; Eleftheriadis, Konstantinos; Gerasopoulos, Evangelos; Mihalopoulos, Nikos; Pandis, Spyros

    2014-05-01

    A field campaign was conducted in Greece during the summer of 2012 (8 June - 26 July) to investigate ambient particulate matter (PM) levels, chemical composition and contribution of regional and local sources. Simultaneous collection of PM1, PM2.5 and PM10 samples from seven different sampling sites in Greece were collected, two sites in Athens - Ag. Paraskevi Demokritos campus (suburban background), - Penteli (National Observatory of Athens NOA premises, suburban background), one in Thessaloniki (suburban background), two stations in Patras - Centre (urban background), - suburbs/ICE FORTH campus (suburban background), one at Finokalia in the northeast part of Crete (remote background) and the last one at the Navarino Environmental Observatory (NEO) in southwest Peloponnese (rural background). These different background sites were chosen in order to estimate both the local emissions sources and the long range transport. A suite of continuous/online instruments were deployed in selected sites including an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF AMS), an Aerosol Chemical Speciation Monitor (ACSM), a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), a Tapered Element Oscillating Microbalance (TEOM), Nephelometers and Aethalometers, gas-phase monitors, etc. The collected filter samples from all sites were analyzed for major ions, OC/EC, metals, etc. The fine PM mass concentration and chemical measurements were quite similar in all sites suggesting significant contributions of transported regional pollution and smaller contributions of local sources. The campaign average PM2.5 ranged from 17.5 to 20 μg m-3 for the different sites. The Athens suburban site in Demokritos had the highest concentration PM2.5 levels. Sulphates and organics were the major PM2.5 components while nitrates, mineral dust and sea-salt for the coastal areas were also important for the PM10 fraction. The sulphate levels were similar in all sites, while the

  10. Diversity and Composition of Airborne Fungal Community Associated with Particulate Matters in Beijing during Haze and Non-haze Days

    PubMed Central

    Yan, Dong; Zhang, Tao; Su, Jing; Zhao, Li-Li; Wang, Hao; Fang, Xiao-Mei; Zhang, Yu-Qin; Liu, Hong-Yu; Yu, Li-Yan

    2016-01-01

    To assess the diversity and composition of airborne fungi associated with particulate matters (PMs) in Beijing, China, a total of 81 PM samples were collected, which were derived from PM2.5, PM10 fractions, and total suspended particles during haze and non-haze days. The airborne fungal community in these samples was analyzed using the Illumina Miseq platform with fungi-specific primers targeting the internal transcribed spacer 1 region of the large subunit rRNA gene. A total of 797,040 reads belonging to 1633 operational taxonomic units were observed. Of these, 1102 belonged to Ascomycota, 502 to Basidiomycota, 24 to Zygomycota, and 5 to Chytridiomycota. The dominant orders were Pleosporales (29.39%), Capnodiales (27.96%), Eurotiales (10.64%), and Hypocreales (9.01%). The dominant genera were Cladosporium, Alternaria, Fusarium, Penicillium, Sporisorium, and Aspergilus. Analysis of similarities revealed that both particulate matter sizes (R = 0.175, p = 0.001) and air quality levels (R = 0.076, p = 0.006) significantly affected the airborne fungal community composition. The relative abundance of many fungal genera was found to significantly differ among various PM types and air quality levels. Alternaria and Epicoccum were more abundant in total suspended particles samples, Aspergillus in heavy-haze days and PM2.5 samples, and Malassezia in PM2.5 samples and heavy-haze days. Canonical correspondence analysis and permutation tests showed that temperature (p < 0.01), NO2 (p < 0.01), PM10 (p < 0.01), SO2(p < 0.01), CO (p < 0.01), and relative humidity (p < 0.05) were significant factors that determine airborne fungal community composition. The results suggest that diverse airborne fungal communities are associated with particulate matters and may provide reliable data for studying the responses of human body to the increasing level of air pollution in Beijing. PMID:27148180

  11. Riverine Composition and Estuarine Geochemistry of Particulate Metals in China—Weathering Features, Anthropogenic Impact and Chemical Fluxes

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Liu, C. L.

    2002-06-01

    Suspended sediments from large and middle size Chinese estuaries, including the Yalujiang, Shuangtaizihe, Luanhe, Jiaojiang and Zhujiang, were analysed to understand trace metal transport in the coastal zone. The determinations of 13 major and trace elements plus organic carbon were made of total concentrations and were fully validated by certified reference materials (CRMs). The combination of the data sets with other Chinese estuaries, such as Changjiang and Huanghe, provides an overview of particulate trace metal geochemistry in this region. Trace metal levels in Chinese rivers are relatively low compared with those draining industrialized regions of Europe and North America. In the estuaries, most particulate elements illustrate stable distribution in the mixing zone until a salinity of 30, especially when absolute concentrations are normalized to aluminium, although the total suspended matter (TSM) is quite different in time and space. Using Al as a reference, it was estimated that 25-40% for Cu, and 5-20% for Pb could remain in labile part in the Jiaojiang, Shuangtaizihe and Zhujiang, whereas different features of labile elements were found in the Changjiang and Luanhe. The mean enrichment factor (EFm) increases with higher sewage to river runoff ratio (S/R) over the drainage basin and EFm for suspended matter is higher than that for bottom sediments. Finally, inputs of particulate trace metals to the coast are estimated based on the riverine sediment load and chemical compositions.

  12. Relationship between chemical composition and pulmonary toxicity of source-specific ambient particulate matter

    EPA Science Inventory

    Epidemiological studies have reported incidence of cardio-pulmonary disease associated with increase in particulate matter (PM) exposure. In this study, the pulmonary toxicity potential of combustion and ambient PM were investigated using data from animal studies at the US EPA....

  13. Chemical Composition and Source Apportionment of Size Fractionated Particulate Matter in Cleveland, Ohio, USA

    EPA Science Inventory

    The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM 2.5 ) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible...

  14. The origin of particulate organic carbon in the marine atmosphere as indicated by its stable carbon isotopic composition

    NASA Astrophysics Data System (ADS)

    Chesselet, R.; Fontugne, M.; Buat-Ménard, P.; Ezat, U.; Lambert, C. E.

    1981-04-01

    Organic carbon concentration and isotopic composition were determined in samples of atmospheric particulate matter collected in 1979 at remote marine locations (Enewetak atoll, Sargasso Sea) during the SEAREX (Sea-Air Exchange) program field experiments. Atmospheric Particulate Organic Carbon (POC) concentrations were found to be in the range of 0.3 to 1.2µg.m-3, in agreement with previous literature data. The major mass of POC was found on the smallest particles (r<0.5µm). The 13C/12C of the small particles is close to the one expected (δ13C = 26 ± 2‰) for atmospheric POC of continental origin. For all the samples analysed so far, it appears that more than 80% of atmospheric POC over remote marine areas is of continental origin. This can be explained either by long-range transport of small sized continental organic aerosols or by the production of POC in the marine atmosphere from a vapor phase organic carbon pool of continental origin. The POC in the large size fraction of marine aerosols (<20% of the total concentration) is likely to have a direct marine origin since its carbon isotopic composition is close to the expected value (δ13C = -21 ± 2‰) for POC associated with sea-salt droplets transported to the marine atmosphere.

  15. Origin of particulate organic carbon in the marine atmosphere as indicated by it stable carbon isotopic composition

    SciTech Connect

    Chesselet, R.; Fontugne, M.; Buat-Menard, P.; Ezat, U.; Lambert, C.E.

    1981-04-01

    Organic carbon concentration and isotopic composition were determined in samples of atmospheric particulate matter collected in 1979 at remote marine locations (Enewetak atoll, Sargasso Sea) during the SEAREX (Sea-Air Exchange) program field experiments. Atmospheric Particulate Organic Carbon (POC) concentrations were found to be in the range of 0.3 to 1.2 mg. m/sup -3/, in agreement with previous literature data. The major mass of POC was found on the smallest particles (r<0.5 mm). The /sup 13/C//sup 12/C of the small particles is close to the one expected (d/sup 13/C = 26 +- 2/sup 0///sub infinity/) for atmospheric POC of continental origin. For all the samples analysed so far, it appears that more than 80% of atmospheric POC over remote marine areas is of continental origin. This can be explained either by long-range transport of small sized continental organic aserosols or by the production of POC in the marine atmosphere from a vapor phase organic carbon pool of continental origin. The POC in the large size fraction of marine aerosols (<20% of the total concentration) is likely to have a direct marine origin since its carbon isotopic composition is close to the expected value (d/sup 13/C = -21 +- 2/sup 0///sub 00/) for POC associated with sea-salt droplets transported to the marine atmosphere.

  16. Effect of SiC and Graphite Particulates Addition on Wear Behaviour of Al2219 Alloy Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Nagaral, Madeva; Shivananda, B. K.; Jayachandran; Auradi, V.; Kori, S. A.

    2016-09-01

    In this investigation wear behaviour of A12219 alloy reinforced with SiC and graphite particulates were studied. The percentage of silicon carbide and graphite as reinforcements were varied from 2 wt.% to 4 wt.% in steps of 2. Energy dispersive spectroscopy and scanning electron microphotographs were used to confirm the presence of SiC and graphite particulates and its uniform distribution over the aluminum matrix. Wear behaviour of aluminum alloy Al2219 reinforced with silicon carbide and graphite fabricated by stir casting process was investigated. The wear properties of the metal matrix composites were studied by performing dry sliding wear test using a pin-on-disc wear tester. The experiments were conducted at a constant sliding velocity of 1.73m/s over a load of 2kg. The results showed that the wear resistance of Al2219-2%SiC-2% graphite and Al2219-4%SiC-4% graphite composites were better than the unreinforced alloy. The wear in terms of weight loss and wear rate was found to decrease with the increasing the weigh percentages of SiC and graphite. To study the dominant sliding wear mechanism worn surfaces were analyzed using scanning electron microscopy.

  17. A Case-Crossover Study between Fine Particulate Matter Elemental Composition and Emergency Admission with Cardiovascular Disease

    PubMed Central

    Huang, Zhijun; Zhou, Yuqing; Lu, Yao; Duan, Yizhu; Tang, Xiaohong; Deng, Qihong; Yuan, Hong

    2017-01-01

    Background It is generally understood that Fine Particulate Matter (PM2.5) can cause high blood pressure. However, it remains unclear whether there is a relationship between the elemental composition of PM2.5 and cardiovascular disease in emergency department patients. Methods Crossover design for time stratified cases and conditional logistic regression were used to analyze the correlation between emergency admissions for cerebral hemorrhage, cerebral infarction, TIA (Transient ischemic attack), coronary heart disease and PM2.5, concentrations of chemical element compositions, and Particulate Matter 10 (PM10) in Changsha city. Results When the temperature, atmosphere pressure, maximum wind speed, NO2 and SO2 were adjusted, the OR (Odd Ratio) of cerebral hemorrhage was 1.177 [95% confidence interval (CI): 1.006-1.376, p = 0.04] with every10 μg/m3 increase of PM2.5. PM10 was unrelated to cardiovascular emergencies (p > 0.05). In addition, with each additional IQR (Interquartile Range) increase of Ni, Zn and Pb concentrations in PM2.5, the values of OR were 1.826 (95% CI: 1.031-3.233), 1.568 (95% CI: 1.015-2.423) and 1.682 (95% CI: 1.010-2.800), respectively. Conclusions Concentration rises of nickel, zinc and lead elements for PM2.5 in Changsha city were related to the increase of emergency admissions with cerebral hemorrhage. PMID:28115809

  18. Elemental composition of suspended particulates as functions of space and time in Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    Neustadter, H. E.; King, R. B.; Fordyce, J. S.

    1975-01-01

    An approach to the analysis of a very large elemental concentration data set. The particular data considered was generated by instrumental neutron activation and emission spectroscopy analyses of over 750 24-hour ambient air particulate samples collected at 16 sites in Cleveland, Ohio, during the 15 months from August 1971 thru October 1972. Examples are presented that show the use of multiple approaches to interpreting the data, including pairwise correlation statistics, selective data plotting and cluster analysis.

  19. Composition and comparative toxicity of particulate matter emitted from a diesel and biodiesel fuelled CRDI engine

    NASA Astrophysics Data System (ADS)

    Gangwar, Jitendra N.; Gupta, Tarun; Agarwal, Avinash K.

    2012-01-01

    There is a global concern about adverse health effects of particulate matter (PM) originating from diesel engine exhaust. In the current study, parametric investigations were carried out using a CRDI (Common Rail Direct Injection) diesel engine operated at different loads at two different engine speeds (1800 and 2400 rpm), employing diesel and 20% biodiesel blends (B20) produced from Karanja oil. A partial flow dilution tunnel was employed to collect and measure the mass of the primary particulates from diesel and biodiesel blend collected on a 47 mm quartz substrate. The collected PM (particulate matter) was subjected to chemical analyses in order to assess the amount of Benzene Soluble Organic Fraction (BSOF) and trace metals using Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). For both diesel and biodiesel, BSOF results showed decreasing levels with increasing engine load. B20 showed higher BSOF as compared to those measured with diesel. The concentration of different trace metals analyzed also showed decreasing trends with increasing engine loads. In addition, real-time measurements for Organic Carbon (OC), Elemental Carbon (EC) and total particle-bound Polycyclic Aromatic Hydrocarbons (PAHs) were carried out on the primary engine exhaust coming out of the partial flow dilution tunnel. Analysis of OC/EC data suggested that the ratio of OC to EC decreases with corresponding increase in engine load for both fuels. A peak in PAH concentration was observed at 60% engine load at 1800 rpm and 20% engine load at 2400 rpm engine speeds almost identical for both kinds of fuels. Comparison of chemical components of PM emitted from this CRDI engine provides new insight in terms of PM toxicity for B20 vis-a-vis diesel.

  20. Elemental composition of airborne particulates and source identification - An extensive one year survey. [in Cleveland, OH

    NASA Technical Reports Server (NTRS)

    King, R. B.; Fordyce, J. S.; Antoine, A. C.; Leibecki, H. F.; Neustadter, H. E.; Sidik, S. M.

    1976-01-01

    Concentrations of 60 chemical elements in the airborne particulate matter were measured at 16 sites in Cleveland, OH over a 1 year period during 1971 and 1972 (45 to 50 sampling days). Analytical methods used included instrumental neutron activation, emission spectroscopy, and combustion techniques. Uncertainties in the concentrations associated with the sampling procedures, the analytical methods, the use of several analytical facilities, and samples with concentrations below the detection limits are evaluated in detail. The data are discussed in relation to other studies and source origins. The trace constituent concentrations as a function of wind direction are used to suggest a practical method for air pollution source identification.

  1. Elemental composition of airborne particulate matter from Santiago City, Chile, 1976

    SciTech Connect

    Prendez, M.; Ortiz, J.L.; Cortes, E.; Cassorla, V.

    1984-01-01

    In Chile, the State Public Health Office (Ministerio de Salud Publica) is responsible for pollution control and for air quality. This office has been monitoring only toxic gases and total suspended particulate matter. The present work is the first study in Chile designed to determine trace elements and their concentrations in particulate matter in the air. By use of enrichment factors, 25 trace elements were classified according to natural or anthropogenic origin. There were two sampling periods: July (winter) and September (spring) 1976. Four sites were studied, located about 6 km north, south, west and east of downtown Santiago. The south, north and west sites are urban and 55 m above sea level. The east site is suburban and approximately 270 m higher than the others. Twenty-four-hour samples were collected on Whatman-41 cellulose filter paper, in a modified stainless steel Buchner funnel. Approximately 10 m/sup 3/ were used at the urban sites and 200 m/sup 3/ at the suburban site. Instrumental neutron activation analysis (INAA) was used as the analytical technique.

  2. Abundance, distribution, and isotopic composition of particulate black carbon in the northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Yang, Weifeng; Guo, Laodong

    2014-11-01

    There exists increasing evidence supporting the important role of black carbon in global carbon cycles. Particulate black carbon (PBC) is allochthonous and has distinct reactivities compared to the bulk particulate organic carbon (tot-POC) in marine environments. However, the abundance, geochemical behavior of PBC and its importance in oceanic carbon budget remain poorly understood. Here we report the abundance, distribution, and stable isotopic signatures of BC derived from the chemo-thermal oxidation (CTO-375) method (BCCTO) in the Gulf of Mexico. Our results show that BCCTO abundance decreased from shelf to basin, and more than a half of riverine BCCTO could be removed over the shelf. Moreover, BCCTO is much more refractory compared to the tot-POC and has δ13C values lower than those of BC-excluded POC. These results highlight the significance of PBC in marine carbon cycles and potentially suggest the need for a new end-member term in quantifying POC sources in the ocean.

  3. Tensile Properties of Nano AL2O3 Particulate-Reinforced Aluminum Matrix Composites by Mechanical Alloying and Hot Extrusion

    NASA Astrophysics Data System (ADS)

    Mehdinia, M.; Jenabali Jahromi, S. A.

    The powder of the micro Al and variant volume fractions of nano Al2O3 were milled by a high energy planetary ball-mill. By milling, a homogenous distribution of nano Al2O3 particles in the metal matrix were developed. Then the milled powder was cold compressed and sintered at 545°C for one hr. The mold and the sintered sample hold in a furnace until the temperature reached 545°C. Then the hot 27mm diameter sample was extruded to 6mm diameter. From the extruded specimens, tensile, hardness and microstructure of the prepared specimens were determined. By these tests the effect of milling time, the percent of nano-particles and the microstructure were evaluated. The hardness and tensile behaviors of aluminum matrix composites reinforced with nano Al2O3 particulate have been found to increase remarkably with the volume fraction of the reinforcement.

  4. Particulate matter, carbon emissions and elemental compositions from a diesel engine exhaust fuelled with diesel-biodiesel blends

    NASA Astrophysics Data System (ADS)

    Ashraful, A. M.; Masjuki, H. H.; Kalam, M. A.

    2015-11-01

    A comparative morphological analysis was performed on the exhaust particles emitted from a CI engine using different blending ratios of palm biodiesel at several operating conditions. It was observed from this experiment; peak particle concentration for PB10 at 1200 rpm is 1.85E + 02 and at 1500 rpm is 2.12E + 02. A slightly smaller amount of volatile material has found from the biodiesel samples compared to the diesel fuel sample. Thermogravimetric analysis (TGA) showed that the amount of volatile material in the soot from biodiesel fuels was slightly lower than that of diesel fuel. PB20 biodiesel blends reduced maximum 11.26% of volatile matter from the engine exhaust, while PB10 biodiesel blend reduced minimum 5.53% of volatile matter. On the other hand, the amount of fixed carbon from the biodiesel samples was slightly higher than diesel fuel. Analysis of carbon emissions, palm biodiesel (PB10) reduced elemental carbon (EC) was varies 0.75%-18%, respectively. Similarly, the emission reduction rate for PB20 was varies 11.36%-23.46% respectively. While, organic carbon (OC) emission rates reduced for PB20 was varied 13.7-49% respectively. Among the biodiesel blends, PB20 exhibited highest oxygen (O), sulfur (S) concentration and lowest silicon (Si) and iron (Fe) concentration. Scanning electron microscope (SEM) images for PB20 showed granular structure particulates with bigger grain sizes compared to diesel. Particle diameter increased under the 2100-2400 rpm speed condition and it was 8.70% higher compared to the low speed conditions. Finally, the results indicated that the composition and degree of unsaturation of the methyl ester present in biodiesel, play an important role in the chemical composition of particulate matter emissions.

  5. The Southeastern Aerosol Research and Characterization Study, Part 3: Continuous measurements of fine particulate matter mass and composition

    SciTech Connect

    Edgerton, E.S.; Hartsell, B.E.; Saylor, R.D.; Jansen, J.J.; Hansen, D.A.; Hidy, G.M.

    2006-09-15

    Deployment of continuous analyzers in the Southeastern Aerosol Research and Characterization Study (SEARCH) network began in 1998 and continues today as new technologies are developed. Measurement of fine particulate matter (PM2.5) mass is performed using a dried, 30 {sup o}C tapered element oscillating microbalance (TEOM). TEOM measurements are complemented by observations of light scattering by nephelometry. Measurements of major constituents include: (1) SO{sub 4}{sup 2-} via reduction to SO{sub 2}; (2) NH{sub 4}{sup +} and NO{sub 3}{sup -} via respective catalytic oxidation and reduction to NO, (3) black carbon (BC) by optical absorption,(4) total carbon by combustion to CO{sup 2}, and (5) organic carbon by difference between the latter two measurements. Several illustrative examples of continuous data from the SEARCH network are presented. A distinctive composite annual average diurnal pattern is observed for PM2.5 mass, nitrate, and BC, likely indicating the influence of traffic-related emissions, growth, and break up of the boundary layer and formation of ammonium nitrate. Examination of PM2.5 components indicates the need to better understand the continuous composition of the unmeasured 'other' category, because it contributes a significant fraction to total mass during periods of high PM2.5 loading. Selected episodes are presented to illustrate applications of SEARCH data. An SO{sub 2} conversion rate of 0.2%/hr is derived from an observation of a plume from a coal-fired power plant during early spring, and the importance of local, rural sources of NH{sub 3} to the formation of ammonium nitrate in particulate matter (PM) is demonstrated. 41 refs., 15 figs., 3 tabs.

  6. Process for stabilization of titanium silicide particulates within titanium aluminide containing metal matrix composites

    SciTech Connect

    Christodoulou, L.; Williams, J.C.; Riley, M.A.

    1990-04-10

    This paper describes a method for forming a final composite material comprising titanium silicide particles within a titanium aluminide containing matrix. It comprises: contacting titanium, silicon and aluminum at a temperature sufficient to initiate a reaction between the titanium and silicon to thereby form a first composite comprising titanium silicide particles dispersed within an aluminum matrix; admixing the first composite with titanium and zirconium to form a mixture; heating the mixture to a temperature sufficient to convert at least a portion of the aluminum matrix to titanium aluminide; and recovering a final composite material comprising titanium silicide particles dispersed within a titanium aluminide containing matrix.

  7. Isotopic composition of nitrate and particulate organic matter in a pristine dam reservoir of western India: implications for biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Bardhan, Pratirupa; Naqvi, Syed Wajih Ahmad; Karapurkar, Supriya G.; Shenoy, Damodar M.; Kurian, Siby; Naik, Hema

    2017-02-01

    Isotopic composition of nitrate (δ15N and δ18O) and particulate organic matter (POM; δ15N and δ13C) were measured in the Tillari Reservoir, located at the foothills of the Western Ghats, Maharashtra, western India. The reservoir, which is stratified during spring-summer and autumn seasons but gets vertically mixed during the southwest monsoon (SWM) and winter, is characterized by diverse redox nitrogen transformations in space and time. The δ15N and δ18O values of nitrate were low (δ15N = 2-10 ‰, δ18O = 5-8 ‰) during normoxic conditions but increased gradually (the highest at δ15N = 27 ‰, δ18O = 29 ‰) when anoxic conditions facilitated denitrification in the hypolimnion during spring-early summer. Once nitrate was fully utilized and sulfidic conditions set in, NH4+ became the dominant inorganic N species, with δ15N ranging from 1.3 to 2.6 ‰. Low δ15N (˜ -5 ‰) and δ13C (-37 to -32 ‰) of POM co-occurring with high NH4+ and CH4 in sulfidic bottom waters were probably the consequence of microbial chemosynthesis. Assimilation of nitrate in the epilimnion was the major controlling process on the N isotopic composition of POM (δ15N = 2-6 ‰). Episodic low δ15N values of POM (-2 to 0 ‰) during early summer, coinciding with the absence of nitrate, might arise from N fixation, although further work is required to confirm the hypothesis. δ13C POM in the photic zone ranged between -29 and -27 ‰ for most parts of the year. The periods of mixing were characterized by uniform δ15N-NO3- and δ18O-NO3- at all depths. Higher POM (particulate organic carbon, POC, as well as particulate organic nitrogen, PON) contents and C / N values with lower δ13C POM during the SWM point to allochthonous inputs. Overall, this study, the first of its kind in the Indian subcontinent, provides an insight into biogeochemistry of Indian reservoirs, using stable carbon and nitrogen isotopes as a tool, where the monsoons play an important role in controlling vertical

  8. Fracto-emission from fiber-reinforced and particulate filled composites

    NASA Technical Reports Server (NTRS)

    Dickinson, J. T.; Jahan-Latibari, A.; Jensen, L. C.

    1985-01-01

    Fracto-emission (FE) in the emission of particles and photons during and following crack propagation. The types of particles observed include electrons (EE), positive ions (PIE), photons (phE), and excited and ground state neutral emission (NE). In this paper work is presented on the characterization of the various FE components and measurements relating FE to the fracture events and material properties involved. FE characteristics measured include total emission, time dependence relative to crack propagation, species of neutral and ionic components, energy of charged species, and time correlations between pairs of FE components. Experiments on fracture of epoxy, single fibers, fiber/epoxy strands, particulate filled epoxy, and multi-ply fiber/epoxy systems will be presented.

  9. Watershed Fire Regime Effects On Particulate Organic Carbon Composition in Oregon and California Coast Range Rivers

    NASA Astrophysics Data System (ADS)

    Hatten, J. A.; Goni, M. A.; Wheatcroft, R. A.; Borgeld, J. C.; Padgett, J. S.; Pasternack, G. B.; Gray, A. B.; Watson, E. B.; Warrick, J. A.

    2010-12-01

    Fire causes major changes to organic carbon, converting biological organic materials to pyrogenic-derived organic carbon (Py-OC), including black carbon. Wildfire also dramatically affects hydrological and erosion processes within watersheds, potentially increasing the erosion and discharge of Py-OC as particulate organic carbon (POC). We hypothesize that the proportion of the POC being discharged as Py-OC will be affected by the watershed’s fire regime, increasing with annual proportion of the watershed burned. During the 2008 and 2009 water years, suspended sediment samples were collected from the Alsea, Umpqua, Eel, Salinas, and Arroyo Seco Rivers draining the Coast Ranges of Oregon and California. Events and discharges of various magnitudes were captured in this sample set. This sample set also included suspended sediment collected from the Arroyo Seco River after a 2008 wildfire burned through a large portion of its watershed. Fine (<63 μm) and coarse (>63 μm) particulate material was analyzed for OC and N. We used cupric oxide oxidation to determine the contribution of Py-OC and unburned organic matter to the POC load of these rivers. The area weighted mean fire return interval decreases from the Douglas fir dominated forests in the Alsea River watershed in the north to the chaparral dominated Arroyo Seco River watershed in the south (Alsea > Umpqua > Eel > Salinas > Arroyo Seco). This translated into an increase in the proportion of each watershed burned from north to south. With the increase in annual proportion of watershed burned we found that the Py-OC content of coarse and fine POC increased from north to south. These results suggest that fire plays an important role in delivering POC to long-term carbon sinks in the coastal and ocean environment.

  10. Contrasting iron isotopic compositions in river suspended particulate matter: the Negro and the Amazon annual river cycles

    NASA Astrophysics Data System (ADS)

    dos Santos Pinheiro, Giana Márcia; Poitrasson, Franck; Sondag, Francis; Cochonneau, Gérard; Vieira, Lucieth Cruz

    2014-05-01

    Iron isotopic compositions (δFeIRMM-1456) of suspended particulate matter (SPM) from two major rivers in the Amazon Basin, the Amazon River itself (at the Óbidos Station) and the Negro River (at the Serrinha Station), were investigated in the present study. The main objective was to search for temporal variations during their annual river cycles. δFeIRMM-1456 values for the Amazon River at Óbidos range between 0.00 and +0.15‰, indistinguishable from the average continental crust value. In contrast, the iron isotopic compositions of the Negro River (Serrinha Station) SPM vary between -0.34 and -0.82‰, whereas the dissolved matter is isotopically heavier in this river. The lack of significant isotopic variations in the Amazon River indicates that one individual SPM subsurface sample is representative of the river during the whole annual river cycle, in opposition to results obtained for the Negro River. The data suggest that in organic-poor white water rivers, such as the Amazon, iron isotopic signatures of the suspended fraction reflect a detrital crustal component with little isotopic fractionation. On the other hand, in the organic-rich Negro River, which has tropical podzols as the main iron source, the iron redox cycling at the water-soil interface influences the iron isotopic composition.

  11. Elevated temperature slow plastic deformation of NiAl-TiB2 particulate composites at 1200 and 1300 K

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Viswanadham, R. K.; Mannan, S. K.; Sprissler, B.

    1990-01-01

    Elevated temperature compression testing has been conducted in air at 1200 and 1300 K with strain rates varying from about 10 to the -4th to about 10 to the -7th/sec on NiAl-TiB2 particulate composites. These materials, which consisted of a B2 crystal structure intermetallic Ni-50 at. pct Al matrix and from 0 to 30 vol pct of approximately 1- micron diameter TiB2 particles, were fabricated by XD synthesis and hot pressed to full density. Flow strength of the composites increased with volume fraction of the strengthening phase with NiAl-30TiB2 being approximately three times stronger than NiAl. Comparison of the light optical and TEM microstructures of as-received and tested samples revealed that reactions did not occur between the two phases, and NiAl-TiB2 interfaces were not cracked during deformation. Additional TEM indicated that the particles stabilize a vastly different microstructure in the NiAl matrix of the composites than that formed in unreinforced NiAl.

  12. Origin, composition and quality of suspended particulate organic matter in relation to freshwater inflow in a South Texas estuary

    NASA Astrophysics Data System (ADS)

    Lebreton, Benoit; Beseres Pollack, Jennifer; Blomberg, Brittany; Palmer, Terence A.; Adams, Leslie; Guillou, Gaël; Montagna, Paul A.

    2016-03-01

    South Texas has a semi-arid climate with a large interannual variability of freshwater inflows. This study sought to define how changes in freshwater inflow affect the composition, quantity and quality of suspended particulate organic matter (SPOM) in a South Texas estuary: the Mission-Aransas estuary. The study was implemented 1.5 months after a large rain event in September 2010 and continued for 10 months of drought conditions. The composition of SPOM originating from rivers, the Gulf of Mexico and the estuary were determined using stable isotopes (δ13C, δ15N and δ34S). The quantity and quality of SPOM were assessed using organic carbon content, chlorophyll a concentrations and C/chl a ratios. Our results demonstrated that autochthonous phytoplankton was the dominant component of SPOM in the Mission-Aransas estuary during droughts. Benthic organic matter from local primary producers (i.e., seagrass, salt marsh plants, benthic microalgae) did not influence SPOM composition, either as fresh material or as detritus. A comparison with a positive estuary (i.e., Sabine-Neches estuary, TX) indicates that decreases in freshwater inflow may lead to decreases of terrestrial organic matter inputs and to increase the ratio of autochtonous phytoplanktonic material in SPOM.

  13. A seasonal study of particulate organic matter composition and quality along an offshore transect in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Le Guitton, M.; Soetaert, K.; Sinninghe Damsté, J. S.; Middelburg, J. J.

    2017-03-01

    We investigated temporal differences in particulate organic matter (POM) composition and quality in the water column and sediment at three stations along a transect from the coast via Oyster Grounds to Dogger Bank within the southern North Sea, using a multiproxy approach covering a wide spectrum of organic matter (OM) degradation states. Results of pigments and phospholipid-derived fatty acids showed distinct OM composition and quality differences in these stations, as well as seasonal variations. Major events, such as a late fall bloom at Dogger Bank and a spring bloom at Oyster Grounds and the Coastal Station were highlighted and the semi-depositional status of Oyster Grounds was confirmed. The OM composition and quality were relatively constant in the upper 10 cm of the sediment at all stations. Finally, this study highlights the importance of lateral and vertical transport processes in seasonal variations in the biogeochemical carbon cycle in this area and the intense pre-depositional processing before eventual burial in coastal settings.

  14. Surface charge migration and dc surface flashover of surface-modified epoxy-based insulators

    NASA Astrophysics Data System (ADS)

    Li, Chuanyang; Hu, Jun; Lin, Chuanjie; Zhang, Boya; Zhang, Guixin; He, Jinliang

    2017-02-01

    Epoxy-based model insulators were manufactured and fluorinated under a F2/N2 mixture (12.5% F2) at 50 °C and 0.1 MPa for 15 min and 60 min. Surface charge accumulation and decay behavior were studied with and without dc voltage application. The effect of direct fluorination on surface charge migration as well as on flashover voltage was verified. The obtained results show that the charge decay of epoxy-based insulators is a slow process, but the decay rate increases when an outer dc electric field is applied. The surface charge distribution is changed when a streamer is triggered on the insulator surface. The existence of heteropolarity surface charges can decrease the dc surface flashover voltage to some extent, while the surface flashover voltage is almost unchanged when charges of the same polarity accumulate on the insulator surface. The short time fluorinated insulator can modify the surface resistivity, and the rate of surface charge dissipation is greatly increased under a dc electric field.

  15. The Effect of Composition, Size, and Solubility on Acute Pulmonary Injury in Rats Following Exposure to Mexico City Ambient Particulate Matter Samples

    EPA Science Inventory

    Particulate matter (PM) associated metals contribute to the adverse cardiopulmonary effects following exposure to air pollution. Here, we investigated how variation in the composition and size of ambient PM collected from two distinct regions in Mexico City relates to toxicity d...

  16. Development and characterization of metal-diboride-based composites toughened with ultra-fine SiC particulates

    NASA Astrophysics Data System (ADS)

    Monteverde, Frédéric; Bellosi, Alida

    2005-05-01

    Two metal-diboride-based ceramics containing up to 15 vol%. ultra-fine α-SiC particulates were developed from commercially available powders. The primary matrix of the composites was ZrB 2 or a mixture of ZrB 2 and HfB 2. With the assistance of 4.5 vol%. ZrN as a sintering aid, both the compositions achieved nearly full density after hot-pressing at 1,900 °C. The microstructure was characterized by fine diboride grains ( ≈3 μm average size) and SiC particles dispersed uniformly. Limited amounts of secondary phases like MO 2 and M(C,N), M=Zr or Zr/Hf, were found. The thermo-mechanical data of both the materials offered a promising combination of properties: about 16 GPa of micro-hardness, 5 MPa√ m of fracture toughness and Young's moduli exceeding 470 GPa. The ZrB 2sbnd SiC composite showed values of strength in air of 635 ± 60 and 175 ± 15 MPa at 25 and 1,500 °C, respectively. Likewise, the (ZrB 2 + HfB 2) sbnd SiC composite exhibited values of strength in air of 590 ± 25 and 190 ± 20 MPa at 25 and 1,500 °C, respectively. The composites also displayed good tolerance of conditions of repeated short exposures, 10 minutes each, at 1,700 °C in stagnant air. In such oxidizing conditions, the resistance to oxidation was provided by the formation of a protective silica-based glass coating, the primary oxidation product of SiC. Such a coating encapsulated the specimen coherently, and provided protection to the faces exposed to the hot atmosphere.

  17. Microstructural effects on fracture behavior of particulate composites: Investigation of toughening mechanisms using optical and boundary element methods

    NASA Astrophysics Data System (ADS)

    Kitey, Rajesh

    Particulate polymer composites are used in a variety of engineering applications. These are generally two phase materials with polymeric phase reinforced by a filler phase to improve overall mechanical, thermal and/or dielectric functionalities. From a mechanical perspective, polymers when filled with stiffer particulates generally show enhanced elastic properties and creep resistance. Achieving similar improvement in failure characteristics has not been consistent due to a lack of thorough understanding of microstructural and loading rate effects. This dissertation addresses a few of these issues by studying effects of filler particle size, filler size distribution and filler-matrix adhesion strength on fracture behavior under quasi-static and dynamic loading conditions. Glass-filled epoxy composites consisting of solid spherical particles are studied in this research. Spherical particles of mean dia. (D) 7 mum to 200 mum are used to reinforce epoxy matrix at a constant volume fraction (Vf = 10%) and two different filler-matrix strengths, weak and strong. Optical interferometry in conjunction with high-speed photography is used to quantify crack growth and deformation histories during impact loading. Although elastic characteristics remain unaffected by microstructural variations, significant differences in fracture behaviors are seen. Both weakly and strongly bonded particles in the matrix show higher values of steady-state dynamic fracture toughness, KIss, relative to unfilled material. Filler particle size affects KIss significantly when particles are weakly bonded to the matrix but not when bonded strongly. Weakly bonded fillers result in consistently higher KIss values compared to strongly bonded counterparts. A particle size of 35 mum appears to be the optimum at the chosen Vf. The KIss of two inter-mixed particle sizes (each of 5% Vf) is bounded by the KIss values of the composite with corresponding single particle size. Fracture surface micromeasurements

  18. Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Lasbleiz, M.; Leblanc, K.; Blain, S.; Ras, J.; Cornet-Barthaux, V.; Hélias Nunige, S.; Quéguiner, B.

    2014-10-01

    The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October-November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m-2 for chlorophyll a 314 to 744 mmol m-2 for biogenic silica (BSi), 1106 to 2268 mmol m-2 for particulate organic carbon, 215 to 436 mmol m-2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m-2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the polar front zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size-fractionation and high performance liquid chromatography (HPLC) pigment signatures, whereas the iron-limited reference area was associated with a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from most previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9, respectively) in the iron-fertilized areas compared to the iron-limited reference station (0.13, 1.1, and 5.8, respectively). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From particulate organic carbon (POC), particulate organic nitrogen (PON), and BSi evolutions, we showed that the elemental composition

  19. A dual analysis for recycled particulate composites: linking micro- and macro-mechanics

    SciTech Connect

    Avila, Antonio F.; Rodrigues, Paulo C.M.; Santos, Dagoberto B.; Faria, Ana C.A

    2003-06-15

    The large amount of disposable bottles produced nowadays makes imperative the search for alternative procedures for recycling them since they are not biodegradable. This paper takes into consideration the thermomechanical recycling of post-consumed plastic bottles, especially the ones made of polyethylene terephthalate (PET) and high-density polyethylene (HDPE), and their use as composite materials for engineering applications. As changes on the composite's microstructure can have an influence on macroscopic behavior, a new type of analysis is needed. To be able to evaluate the composite performance, a dual analysis procedure was developed. It consists of a micro-mechanical analysis where the microstructure is observed by optical microscopy, and variations in morphology are related to composite overall mechanical behavior. The macro-mechanical analysis is performed by ASTM D 3039/3039 M tensile tests. By doing this, the composite effective moduli can be determined. The new composite seems to be encouraging, i.e., an HDPE/PET composite with 40:60 ratio, in weight, experiments a stiffness recovery from the third to the fourth recycle. Moreover, the dual analysis was able to capture this variation.

  20. Trends in the elemental composition of fine particulate matter in Santiago, Chile, from 1998 to 2003.

    PubMed

    Sax, Sonja N; Koutrakis, Petros; Rudolph, Pablo A Ruiz; Cereceda-Balic, Francisco; Gramsch, Ernesto; Oyola, Pedro

    2007-07-01

    Santiago, Chile, is one of the most polluted cities in South America. As a response, over the past 15 yr, numerous pollution reduction programs have been implemented by the environmental authority, Comisión Nacional del Medio Ambiente. This paper assesses the effectiveness of these interventions by examining the trends of fine particulate matter (PM(2.5)) and its associated elements. Daily fine particle filter samples were collected in Santiago at a downtown location from April 1998 through March 2003. Additionally, meteorological variables were measured continuously. Annual average concentrations of PM(2.5) decreased only marginally, from 41.8 microg/m3 for the 1998-1999 period to 35.4 microg/m3 for the 2002-2003 period. PM(2.5) concentrations exceeded the annual U.S. Environmental Protection Agency standard of 15 microg/m3. Also, approximately 20% of the daily samples exceeded the old standard of 65 microg/m3, whereas approximately half of the samples exceeded the new standard of 35 microg/m3 (effective in 2006). Mean PM(2.5) levels measured during the cold season (April through September) were three times higher than those measured in the warm season (October through March). Particulate mass and elemental concentration trends were investigated using regression models, controlling for year, month, weekday, wind speed, temperature, and relative humidity. The results showed significant decreases for Pb, Br, and S concentrations and minor but still significant decreases for Ni, Al, Si, Ca, and Fe. The larger decreases were associated with specific remediation policies implemented, including the removal of lead from gasoline, the reduction of sulfur levels in diesel fuel, and the introduction of natural gas. These results suggest that the pollution reduction programs, especially the ones related to transport, have been effective in reducing various important components of PM(2.5). However, particle mass and other associated element levels remain high, and it is thus

  1. Crack growth behavior of encapsulation processed SiC-PMMA particulate composites

    SciTech Connect

    Sheu, C.H.

    1990-05-01

    The effect of processing on the fatigue crack propagation and fracture toughness of ceramic-polymer composites was investigated. A new process for composite production was developed with homogeneous particle distribution and low residual stress levels in mind. PMMA was uniformly distributed by encapsulating the SiC substrate by means of precipitation polymerization. The encapsulation processed powders were then compacted at temperatures above T{sub g} to form the composite. The encapsulation process was optimized by varying the initial concentrations of the reactants until homogeneous nucleation was suppressed. The coatings were found to be continuous at the SiC-PMMA interface, with particle agglomeration occurring between coated particles. Polymer loadings equivalent to 30 vol % SiC were achieved. Composites of several particle size ranges were tested under cyclic fatigue and static loading conditions. Fatigue growth rates and fracture toughness data display a trend of increasing crack growth resistance with increasing particle size, with encapsulation processed composites outperforming conventionally cast composites in both cyclic fatigue and fracture resistance. The largest K{sub Ic} value was found to be 2.95 MPa(m){sup 1/2}, a factor of 3 increase over un-reinforced PMMA. The roles of crack deflection, shielding, bridging, and pinning in enhancing toughness were discussed in light of crack profile fracture surface details. 65 refs., 30 figs., 2 tabs.

  2. Effect of Particle Size on Wear of Particulate Reinforced Aluminum Alloy Composites at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Kumar, Suresh; Pandey, Ratandeep; Panwar, Ranvir Singh; Pandey, O. P.

    2013-11-01

    The present paper describes the effect of particle size on operative wear mechanism in particle reinforced aluminum alloy composites at elevated temperatures. Two composites containing zircon sand particles of 20-32 μm and 106-125 μm were fabricated by stir casting process. The dry sliding wear tests of the developed composites were performed at low and high loads with variation in temperatures from 50 to 300 °C. The transition in wear mode from mild-to-severe was observed with variation in temperature and load. The wear at 200 °C presented entirely different wear behavior from the one at 250 °C. The wear rate of fine size reinforced composite at 200 °C at higher load was substantially lower than that of coarse size reinforced composite. Examination of wear tracks and debris revealed that delamination occurs after run in wear mode followed by formation of smaller size wear debris, transfer of materials from the counter surfaces and mixing of these materials on the contact surfaces. The volume loss was observed to increase with increase in load and temperature. Composite containing bigger size particles exhibit higher loss under similar conditions.

  3. Concentrations and composition of aerosols and particulate matter in surface waters along the transatlantic section

    NASA Astrophysics Data System (ADS)

    Nemirovskaya, I. A.; Lisitzin, A. P.; Novigatsky, A. N.; Redzhepova, Z. U.; Dara, O. M.

    2016-07-01

    Along the transatlantic section from Ushuaia to Gdańsk (March 26-May 7, 2015; cruise 47 of R/V Akademik Ioffe), data were obtained on the concentrations of aerosols in the near-water layer of the atmosphere and of particulate matter in surface waters, as well as of organic compounds within the considered matter (Corg, chlorophyll a, lipids, and hydrocarbons). The concentrations of aerosols amounted to 1237-111 739 particles/L for the fraction of 0.3-1 μm and to 0.02-34.4 μg/m2/day for the matter collected by means of the network procedure. The distribution of aerosols is affected by circumcontinental zoning and by the fluxes from arid areas of African deserts. The maximum concentration of the treated compounds were found in the river-sea frontal area (the runoff of the Colorado River, Argentina), as well as when nearing the coasts, especially in the English Channel.

  4. Chemical Composition and Emission Sources of the Fine Particulate Matters in a Southeast Asian Mega City (Dhaka, Bangladesh)

    NASA Astrophysics Data System (ADS)

    Salam, Abdus

    2016-04-01

    Air pollution has significant impact on human health, climate change, agriculture, visibility reduction, and also on the atmospheric chemistry. There are many studies already reported about the direct relation of the human mortality and morbidity with the increase of the atmospheric particulate matters. Especially, fine particulate matters can easily enter into the human respiratory system and causes many diseases. Particulate matters have the properties to absorb the solar radiation and impact on the climate. Dhaka, Bangladesh is a densely populated mega-city in the world. About 16 million inhabitants are living within an area of 360 square kilometers. Air quality situation has been degrading due to unplanned growth, increasing vehicles, severe traffic jams, brick kilns, industries, construction, and also transboundary air pollution. A rapidly growing number of vehicles has worsen the air quality in spite of major policy interventions, e.g., ban of two-stroke and three-wheeled vehicles, phase out of 20 years old vehicles, conversion to compressed natural gas (CNGs), etc. Introduction of CNGs to reduce air pollution was not the solution for fine particles at all, as evidence shows that CNGs and diesel engines are the major sources of fine particles. High concentration of the air pollutants in Dhaka city such as PM, carbonaceous species (black and organic carbon), CO, etc. has already been reported. PM2.5 mass, chemical composition (e.g., BC, OC, SO42-, NO3-, trace elements, etc.), aerosol Optical Depth (AOD) and emission sources of our recent measurements at the highly polluted south East Asian Mega city (Dhaka) Bangladesh will be presented in the conference. PM2.5 samples were collected on filters with Digital PM2.5 sampler (Switzerland) and Air photon, USA. BC was measured from filters (with thermal and optical method) and also real time with an Aethalometer AE42 (Magee Scitific., USA). Water soluble ions were determined from filters with ion chromatogram. AOD

  5. Variations in the magnitude and composition of particulate organic matter export across a small, mountainous river estuary along Pacific Northwest margin of North America

    NASA Astrophysics Data System (ADS)

    Goni, M. A.

    2015-12-01

    The Pacific Northwest margin of North America is characterized by numerous small mountainous rivers that mobilize the bulk of particulate materials (i.e., inorganic sediment, organic matter) from surrounding watersheds during short-lived, winter-time floods. However, it is unclear how estuarine processes alter the magnitude and composition of the particulate load prior to transport to the ocean. In this presentation, we present results from in-situ observations and rapid-response sampling along a typical river-estuary system (Alsea River/Bay, Oregon) designed to address this issue. We found marked contrasts in the concentrations of sediment and particulate organic matter in the estuary during different river discharge conditions (flood vs. non-flood), with distinct trends associated with contrasting tidal stage (spring/neap). Elemental, isotopic and biomarker analyses of individual samples revealed large differences in the provenance and composition of organic materials mobilized under different discharge/tidal conditions. Continuous, in-situ measurements of current, salinity, temperature and turbidity, combined with the compositions from individual samples allow us to determine instantaneous material fluxes into and out of Alsea Bay. We use these data to derive net fluxes during wintertime conditions and assess the role of floods in the retention and transport of particulate organic matter across the estuarine interface.

  6. Size distributions and elemental compositions of particulate matter on clear, hazy and foggy days in Beijing, China

    NASA Astrophysics Data System (ADS)

    Yang, Yongjie; Wang, Yuesi; Huang, Weiwei; Hu, Bo; Wen, Tianxue; Zhao, Ya'nan

    2010-05-01

    Total suspended particulates (TSP) samples were collected using low pressure impactors (Andersen Series 20-800, USA) on typical clear, hazy and foggy days in Beijing in order to investigate the characteristics of size distributions and elemental compositions of particulate matter (PM) in different weather conditions. The concentrations of sixteen elements, including Na, Mg, Al, K, Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Tl and Pb were detected using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that Ca, Al, Fe, Mg and Ba on foggy days were 2.0-2.6 times higher than on clear days, and 2.3-2.9 times higher than on hazy days. Concentrations of Cu, Zn, As, Se and Pb on foggy days were 163.5, 1186.7, 65.9, 32.0 and 708.2 ng m-3, respectively, in fine particles, and 68.1, 289.5, 19.8, 1.6 and 103.8 ng m-3, respectively, in coarse particles. This was 1.0-8.4 times higher and 1.4-7.4 times higher than on clear and hazy days, respectively. It is then shown that Mg, Al, Fe, Ca and Ba were mainly associated with coarse particles, peaking at 4.7-5.8 µm; that Cd, Se, Zn, As, Tl and Pb were most dominant in fine particles, peaking at 0.43-1.1 µm; and that Na, K, Ni, Cu and Mn had a multi-mode distribution, with peaks at 0.43-1.1 µm and 4.7-5.8 µm. The enrichment factors indicated that coal combustion along with vehicle and industry emissions may be the main sources of pollution elements.

  7. Discharge-related trends in the composition of particulate organic matter exported by small mountainous rivers: results from Oregon and California (Invited)

    NASA Astrophysics Data System (ADS)

    Goni, M. A.; Hatten, J. A.; Wheatcroft, R. A.; Borgeld, J.; Williamson, A.; Padgett, J.; Pasternack, G. B.; Gray, A.; Watson, E. B.

    2009-12-01

    Small mountainous rivers display highly variable discharges on both seasonal and event scales. Previous work has shown marked differences in the composition of the particulate load of rivers collected at different stages of the hydrograph, but fewer studies have specifically investigated how the biogeochemical compositions of particulate organic matter change as a function of discharge and how this variation affects the characteristics of the materials reaching the ocean. We explore these issues using data from three rivers along the west coast of the U.S. (Umpqua, Eel and Salinas) with similar watershed size but contrasting climate, vegetation and land use. Coarse and fine particulate organic matter samples collected at different discharges, including several flood events, were analyzed for carbon and nitrogen content, stable carbon and nitrogen isotopic compositions, radiocarbon compositions and yields of different organic biomarkers (e.g. lignin phenols, cutin acids, amino acid products). This presentation will focus on comparing and contrasting the provenance, age, and biochemical make-up of materials transported by each of the rivers as a function of discharge. Seasonal and event-scale differences in organic matter concentrations and compositions will be the subject of an accompanying poster. We will discuss both the processes responsible for these contrasts and the impacts they have on the delivery and fate of terrigenous organic matter in the coastal ocean.

  8. Diesel particulate control

    SciTech Connect

    Bertelsen, F.I. )

    1988-01-01

    Diesel particulates, because of their chemical composition and extremely small size, have raised health and welfare issues. Health experts have expressed concern that they contribute to or aggravate chronic lung diseases such as asthma, bronchitis and emphysema, and there is the lingering issue about the potential cancer risk from exposure to diesel particulate. Diesel particulates impair visibility, soil buildings, contribute to structural damage through corrosion and give off a pungent odor. Diesel trucks, buses and cars together are such a significant and growing source of particulate emissions. Such vehicles emit 30 to 70 times more particulate matter than gasoline vehicles equipped with catalytic converters. Diesel engines currently power the majority of larger trucks and buses. EPA predicted that, if left uncontrolled, diesel particulate from motor vehicles would increase significantly. Diesel particulate emissions from motor vehicles are particularly troublesome because they frequently are emitted directly into the breathing zone where we work and recreate. The U.S. Congress recognized the risks posed by diesel particulate and as part of the 1977 Clean Air Act Amendments established specific, technology-forcing requirements for controlling these emissions. The U.S. Environmental Protection Agency (EPA) in 1980 established particulate standards for automobiles and light trucks and in 1985, heavy trucks and buses. California, concerned that EPA standards would not adequately protect its citizens, adopted its own set of standards for passenger cars and light trucks. This paper discusses emerging technologies proposed to address the problem.

  9. Size, source and chemical composition as determinants of toxicity attributable to ambient particulate matter

    NASA Astrophysics Data System (ADS)

    Kelly, Frank J.; Fussell, Julia C.

    2012-12-01

    Particulate matter (PM) is a complex, heterogeneous mixture that changes in time and space. It encompasses many different chemical components and physical characteristics, many of which have been cited as potential contributors to toxicity. Each component has multiple sources, and each source generates multiple components. Identifying and quantifying the influences of specific components or source-related mixtures on measures of health-related impacts, especially when particles interact with other co-pollutants, therefore represents one of the most challenging areas of environmental health research. Current knowledge does not allow precise quantification or definitive ranking of the health effects of PM emissions from different sources or of individual PM components and indeed, associations may be the result of multiple components acting on different physiological mechanisms. Some results do suggest a degree of differential toxicity, namely more consistent associations with traffic-related PM emissions, fine and ultrafine particles, specific metals and elemental carbon and a range of serious health effects, including increased morbidity and mortality from cardiovascular and respiratory conditions. A carefully targeted programme of contemporary toxicological and epidemiological research, incorporating more refined approaches (e.g. greater speciation data, more refined modelling techniques, accurate exposure assessment and better definition of individual susceptibility) and optimal collaboration amongst multidisciplinary teams, is now needed to advance our understanding of the relative toxicity of particles from various sources, especially the components and reactions products of traffic. This will facilitate targeted abatement policies, more effective pollution control measures and ultimately, a reduction in the burden of disease attributable to ambient PM pollution.

  10. Particle size distributions and elemental composition of atmospheric particulate matter in southern Italy.

    PubMed

    Sprovieri, Francesca; Pirrone, Nicola

    2008-06-01

    Three 2-wk seasonal field campaigns were performed in 2003 and 2004 at a sampling site on the southern Tyrrhenian coast of Italy with the aim to investigate the dynamics and characteristics of particle-bound pollutants in the Mediterranean area. Fine (PM(2.5)) and coarse particulate matter (PM(10-2.5)) size fractions were collected by a manual dichotomous sampler on 37-mm Teflon filters over a 24-hr sampling period. On average, 70% of the total PM(10) (PM(2.5) + PM(10-2.5)) mass was associated with the coarse fraction and 30% with the fine fraction during the three campaigns. The ambient concentrations of Pb, Ni, Cr, Zn, Mn, V, Cd, Fe, Cu, Ca, and Mg associated with both size fractions were determined by atomic absorption spectrometry. Ambient concentrations showed differences in their absolute value, ranging from few ng x m(-3) to microg x m(-3), as well as in their variability within the PM(2.5) and PM(10-2.5) size fractions. PM(10) levels were well below the European Union (EU) limit value during the study period with the exception of three events during the first campaign (fall) and five events during the third campaign (spring). Two main sources were identified as the major contributors including mineral dust, transported from North Africa, and sea spray from the Tyrrhenian Sea. Comparing the results with backward trajectories, calculated using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) and Total Ozone Mapping Spectrometer-National Aeronautics and Space Administration (TOMS-NASA) maps, it was observed that in central and eastern Europe, the Tyrrhenian Sea and North Africa were the major emission source regions that affected the temporal variations and daily averages of PM(2.5) and PM(10-2.5) concentrations.

  11. Molecular composition of sugars in atmospheric particulate matter from interior Alaska

    NASA Astrophysics Data System (ADS)

    Haque, Md. Mozammel; Kawamura, Kimitaka; Kim, Yongwon

    2015-04-01

    Sugars can account for 0.5-8% of carbon in atmospheric particulate matter, affecting the earth climate, air quality and public health. Total of 33 total suspended particle (TSP) samples were collected from Fairbanks, Alaska in June 2008 to June 2009 using a low volume air sampler. Here, we report the molecular characteristics of anhydro-sugars (levoglucosan, galactosan and mannosan), primary saccharides (xylose, fructose, glucose, sucrose and trehalose) and sugar alcohols (erythritol, arabitol, mannitol and inositol). The average contribution of sugars to the organic carbon (OC) was also determined to be 0.92%. Sugar compounds were measured using solvent extraction/TMS-derivatization technique followed by gas chromatography-mass spectrometry (GC-MS) determination. The concentrations of total quantified sugar compounds ranged from 2.3 to 453 ng m-3 (average 145 ng m-3). The highest concentration was recorded for levoglucosan in summer, with a maximum concentration of 790 ng m-3 (average 108 ng m-3). Levoglucosan, which is specifically formed by a pyrolysis of cellulose, has been used as an excellent tracer of biomass burning. The highest level of levoglucosan indicates a significant contribution of biomass burning in ambient aerosols. Galactosan (average 20 ng m-3) and mannosan (average 27 ng m-3), which are also formed through the pyrolysis of cellulose/hemicelluloses, were identified in all samples. The average concentrations of arabitol, mannitol, glucose and sucrose were also found 14.7, 14.6, 14.1 and 16.8 ng m-3, respectively. They have been proposed as tracers for resuspension of surface soil and unpaved road dust, which contain biological materials including fungi and bacteria. These results suggest that there is some impact of bioaerosols on climate over Interior Alaska. We will also measure water-soluble organic carbon (WSOC) and inorganic ions for all samples.

  12. Y3Fe5O12/Na,Bi,Sr-doped PZT particulate magnetoelectric composites

    NASA Astrophysics Data System (ADS)

    Lisnevskaya, I. V.; Bobrova, I. A.; Lupeiko, T. G.; Agamirzoeva, M. R.; Myagkaya, K. V.

    2016-05-01

    Magnetoelectric (ME) composites of Na, Bi, Sr substituted lead zirconate titanate (PZT) and yttrium iron garnet having representative formula (100-x) wt% Na,Bi,Sr-doped PZT (PZTNB-1)+x wt% Y3Fe5O12 (YIG) with x=10-90 were manufactured using powdered components obtained through sol-gel processes. It is shown that the decrease in sintering temperature provided by the use of finely dispersed PZTNB-1 and YIG powders allows to significantly reduce content of fluorite-like foreign phase based on zirconium oxide, which forms due to the interfacial interaction during heat treatment and becomes stabilized by yttrium oxide. Connectivity has considerable effect on the value of ME coefficient of composite ceramics. With the same x value, ΔE/ΔH characteristic decreases when changing from 0-3-type structured composites (PZT grains embedded in ferrite matrix) to 3-3-(interpenetrating network of two phases) and especially 3-0-type samples (YIG grains embedded in PZT matrix); in the last case this can be attributed to the substrate clamping effect when ferrite grains are clamped with piezoelectric matrix. ΔE/ΔH value of 0-3 composites with x=40-60 wt% was found to be ∼1.6 mV/(cm Oe).

  13. Mercury partition in the interface between a contaminated lagoon and the ocean: the role of particulate load and composition.

    PubMed

    Pato, P; Otero, M; Válega, M; Lopes, C B; Pereira, M E; Duarte, A C

    2010-10-01

    After having estimated the patterns of flow to the ocean and found some seasonal and tidal differences, mainly with regard to the relative importance of dissolved and particulate fractions, mercury partitioning at the interface between a contaminated lagoon and the Atlantic Ocean was investigated during four tidal cycles in contrasting season and tidal regimes. Mercury was found to be located predominantely in the particulate fraction throughout the year, contributing to its retention within the system. Seasonal conditions, variations in marine and fluvial signals and processes affecting bed sediment resuspension influenced the character and concentration of suspended particulate matter in the water column. Variation in the nature, levels and partitioning of organic carbon in the particulate fraction affected levels of particulate mercury as well as mercury partitioning. These results highlight the dominant role of suspended particulate matter in the distribution of anthropogenic mercury and reinforce the importance of competitive behavior related to organic carbon in mercury scavenging.

  14. Preparation and properties of Al-alloy coconut shell char particulate composites

    NASA Astrophysics Data System (ADS)

    Murali, T. P.; Surappa, M. K.; Rohatgi, P. K.

    1991-12-01

    A technique to produce cast Al-11.8 pct Si alloy composites containing up to 40 vol pct (15 pct by weight) dispersions of 125 µm size coconut shell char particles is described. The technique consists of stirring shell char particles into the vortex created by mechanical stirring of melts and subsequent casting of composite melts in suitable molds. The composite melts were also pressure die cast at a pressure of 100 MPa into cylindrical castings. The incorporation of large volume fraction of shell char particles is aided by (a) preheating of the particles to about 500 ‡C to 600 ‡C for two hours before introduction into the melts, and (b) alloying of Al-11.8 pct Si melts with 3 to 6 pct Mg. Electron Probe Micro Analysis (EPMA) analysis indicated an Mg enriched region around dispersed char particles in the composite indicating that prealloying with Mg probably improves wetting between char particles and the melt. Dispersions of 15 pct wt of char particles lead to decreases in hardness (from 85 BHN to 55 BHN), compression strength (from 542.30 MPa to 218.68 MPa), U. T. S., (from 164.16 MPa to 63.75 MPa), and electrical conductivity (from 27.8 pct I ACS to 11 pct I ACS). However, since these decreases are accompanied by a decrease in density, specific strength values of Al-11.8 pct-shell char composites are adequate for a variety of applications. Adhesive wear rates and friction coefficient values at low sliding speeds (0.56 m per second, and at loads of 10 N and 60 N) decrease with increase in wt pct of char particles under dry conditions.

  15. Preparation and properties of Al-alloy coconut shell char particulate composites

    NASA Astrophysics Data System (ADS)

    Murali, T. P.; Surappa, M. K.; Rohatgi, P. K.

    1982-09-01

    A technique to produce cast Al-11.8 pct Si alloy composites containing up to 40 vol pct (15 pct by weight) dispersions of 125 μm size coconut shell char particles is described. The technique consists of stirring shell char particles into the vortex created by mechanical stirring of melts and subsequent casting of composite melts in suitable molds. The composite melts were also pressure die cast at a pressure of 100 MPa into cylindrical castings. The incorporation of large volume fraction of shell char particles is aided by (a) preheating of the particles to about 500 ° to 600 ° for two hours before introduction into the melts, and (b) alloying of Al-11.8 pct Si melts with 3 to 6 pct Mg. Electron Probe Micro Analysis (EPMA) analysis indicated an Mg enriched region around dispersed char particles in the composite indicating that prealloying with Mg probably improves wetting between char particles and the melt. Dispersions of 15 pct wt of char particles lead to decreases in hardness (from 85 BHN to 55 BHN), compression strength (from 542.30 MPa to 218.68 MPa), U. T. S., (from 164.16 MPa to 63.75 MPa), and electrical conductivity (from 27.8 pct IACS to 11 pct IACS). However, since these decreases are accompanied by a decrease in density, specific strength values of Al-11.8 pct-shell char composites are adequate for a variety of applications. Adhesive wear rates and friction coefficient values at low sliding speeds (0.56 m per second, and at loads of 10 N and 60 N) decrease with increase in wt pct of char particles under dry conditions.

  16. Steady state creep behavior of particulate-reinforced titanium matrix composites

    SciTech Connect

    Ranganath, S.; Mishra, R.S.

    1996-03-01

    The steady state creep behavior of unreinforced Ti, Ti-Ti{sub 2}C and Ti-TiB-Ti{sub 2}C composites has been examined in the temperature range 823--923 K. It is shown that the creep deformation of unreinforced Ti is governed by climb-controlled creep mechanism for which the stress exponent is between 4.1 and 4.3 and the activation energy is 236 kJ mol{sup {minus}1}. For composites, the stress exponents are between 6 and 7 at 823 K but are similar to unreinforced Ti at 923 K. The measured steady state creep rate of composites is found to be 2--3 orders of magnitude lower than unreinforced Ti in the investigated temperature range. It is then established that the origin of creep strengthening at 823--923 K is due to the combined effects of increased modulus of composites and the refined microstructure. It is further shown that the change of stress exponent of composites at 823 K is because of the change in creep mechanism from lattice-diffusion controlled dislocation climb to pipe-diffusion controlled dislocation climb. By analyzing the creep data, a modification in the dimensionless constant, A = 3.2 {times} 10{sup 5} exp({minus}24.2V{sub r}) for lattice-diffusion regime and A = 9.4 {times} 10{sup 5} exp({minus}28.1V{sub r}) for pipe-diffusion regime, where V{sub r} is the volume fraction of reinforcements, is suggested to account for the influence of reinforcements on creep kinetics.

  17. Functionalization of epoxy-based monoliths for ion exchange chromatography of proteins.

    PubMed

    Dinh, Ngoc Phuoc; Cam, Quach Minh; Nguyen, Anh Mai; Shchukarev, Andrei; Irgum, Knut

    2009-08-01

    Macroporous epoxy-based monoliths prepared by emulsion polymerization have been modified for use in ion exchange chromatography (IEC) of proteins. Strong anion exchange functionality was established by iodomethane quaternization of tertiary amine present on the monolith surface as a part of the polymer backbone. The modification pathway to cation exchange materials was via incorporation of glycidyl methacrylate (GMA) brushes which were coated using atom transfer radical polymerization (ATRP). Strong (SO(3)(-)) and weak (COO(-)) cation exchange groups were thereafter introduced onto the GMA-grafted monoliths by reactions with sodium hydrogen sulfite and iminodiacetic acid, respectively. Grafting was confirmed by XPS, gravimetric measurement, and chromatographic behavior of the modified materials toward model proteins. In incubation experiments the proteins were recovered quantitatively with no obvious signs of unfolding after contact with the stationary phase for >2 h. Chromatographic assessments on the functionalized columns as well as problems associated with flow-through modification by ATRP are discussed.

  18. Temporal and Water Column Variability in Particulate Organic Carbon Composition on the Amazon River Main-stem

    NASA Astrophysics Data System (ADS)

    Rosengard, S.; Galy, V.; Spencer, R. G.; McNichol, A. P.

    2015-12-01

    The Amazon River exports ~14 teragrams (0.014 gigatons) of particulate organic carbon (POC) to the Atlantic coast each year, ~15% of the global riverine carbon source to the oceans. Understanding the source and fate of this exported POC is complicated by (1) hydrodynamic sorting of suspended particles in the river cross-section, and (2) seasonality in discharge over the hydrological cycle. Here, we characterize suspended POC composition down the water column (surface-to-bed) and through time (rising discharge in April 2014, falling discharge in July 2014) to assess the extent of and mechanism underlying this variability. Depth-specific sampling of the river cross-section took place at Óbidos, the most downstream gauging station on the main-stem, and was coupled to an Acoustic Doppler Current Profiler to calculate export fluxes at both times. Between April and July, raw water discharge increased from 150,000 to 250,000 m3/s. Bulk compositional features (e.g., % OC, δ13C, C/N) varied with both hydrodynamic sorting and seasonality, while thermal stability, derived from ramped oxidation of the suspended sediments, did not differ with depth or season. Compound-specific δ 13C of extracted lipids varied seasonally, as well. We plan to supplement these preliminary data with measurements of POC 14C content across space and time. The observations thus far suggest that the variability in suspended POC composition with depth and season is dominated by physical changes in source. Moreover, the similarities in thermal stability suggest that POC reactivity, and relatedly, its fate downstream and ultimately in the coastal ocean, is relatively invariant across these variable sources.

  19. Mechanical Properties - Structure Correlation for Commercial Specification of Cast Particulate Metal Matrix Composites

    SciTech Connect

    Pradeep Rohatgi

    2002-12-31

    In this research, the effects of casting foundry, testing laboratory, surface conditions, and casting processes on the mechanical properties of A359-SiC composites were identified. To observe the effects, A359-SiC composites with 20 and 305 SiC particles were cast at three different foundries and tested at three different laboratories. The composites were cast in sand and permanent molds and tested as-cast and machined conditions. To identify the effect of the volume fraction and distribution of particles on the properties of the composites, particle distribution was determined using Clemex Image analysis systems, and particle volume fraction was determined using wet chemical analysis and Clemex Image analysis systems. The microstructure and fractured surfaces of the samples were analyzed using SEM, and EDX analysis was done to analyze chemical reaction between the particles and the matrix. The results of the tensile strengths exhibited that the tensile strengths depend on the density and porosity of the composites; in general the higher tensile strength is associated with lower porosity and higher density. In some cases, composites with lower density were higher than these with higher density. In the Al-20% SiC samples, the composites with more inclusions exhibited a lower tensile strength than the ones with fewer inclusions. This suggests that macroscopic casting defects such as micro-porosity, shrinkage porosity and inclusions appear to strongly influence the tensile strength more than the microstructure and particle distribution. The fatigue properties of A359/20 vol.% SiC composites were investigated under strain controlled conditions. Hysteresis loops obtained from strain controlled cyclic loading of 20% SiCp reinforced material did not exhibit any measurable softening or hardening. The fatigue life of Al-20% SiC heat treated alloy at a given total strain showed wide variation in fatigue life, which appeared to be related to factors such as inclusions

  20. Size and composition distributions of particulate matter emissions: part 1--light-duty gasoline vehicles.

    PubMed

    Robert, Michael A; VanBergen, Saskia; Kleeman, Michael J; Jakober, Christopher A

    2007-12-01

    Size-resolved particulate matter (PM) emitted from light-duty gasoline vehicles (LDGVs) was characterized using filter-based samplers, cascade impactors, and scanning mobility particle size measurements in the summer 2002. Thirty LDGVs, with different engine and emissions control technologies (model years 1965-2003; odometer readings 1264-207,104 mi), were tested on a chassis dynamometer using the federal test procedure (FTP), the unified cycle (UC), and the correction cycle (CC). LDGV PM emissions were strongly correlated with vehicle age and emissions control technology. The oldest models had average ultrafine PM0.1 (0.056- to 0.1-microm aerodynamic diameter) and fine PM1.8 (< or =1.8-microm aerodynamic diameter) emission rates of 9.6 mg/km and 213 mg/km, respectively. The newest vehicles had PM0.1 and PM1.8 emissions of 51 microg/km and 371 microg/km, respectively. Light duty trucks and sport utility vehicles had PM0.1 and PM1.8 emissions nearly double the corresponding emission rates from passenger cars. Higher PM emissions were associated with cold starts and hard accelerations. The FTP driving cycle produced the lowest emissions, followed by the UC and the CC. PM mass distributions peaked between 0.1- and 0.18-microm particle diameter for all vehicles except those emitting visible smoke, which peaked between 0.18 and 0.32 microm. The majority of the PM was composed of carbonaceous material, with only trace amounts of water-soluble ions. Elemental carbon (EC) and organic matter (OM) had similar size distributions, but the EC/OM ratio in LDGV exhaust particles was a strong function of the adopted emissions control technology and of vehicle maintenance. Exhaust from LDGV classes with lower PM emissions generally had higher EC/OM ratios. LDGVs adopting newer technologies were characterized by the highest EC/OM ratios, whereas OM dominated PM emissions from older vehicles. Driving cycles with cold starts and hard accelerations produced higher EC/OM ratios in

  1. Composition and secondary formation of fine particulate matter in the Salt Lake Valley: winter 2009.

    PubMed

    Kuprov, Roman; Eatough, Delbert J; Cruickshank, Tyler; Olson, Neal; Cropper, Paul M; Hansen, Jaron C

    2014-08-01

    Under the National Ambient Air Quality Standards (NAAQS), put in place as a result of the Clean Air Amendments of 1990, three regions in the state of Utah are in violation of the NAAQS for PM10 and PM2.5 (Salt Lake County, Ogden City, and Utah County). These regions are susceptible to strong inversions that can persist for days to weeks. This meteorology, coupled with the metropolitan nature of these regions, contributes to its violation of the NAAQS for PM during the winter. During January-February 2009, 1-hr averaged concentrations of PM10-2.5, PM2.5, NO(x), NO2, NO, O3, CO, and NH3 were measured. Particulate-phase nitrate, nitrite, and sulfate and gas-phase HONO, HNO3, and SO2 were also measured on a 1-hr average basis. The results indicate that ammonium nitrate averages 40% of the total PM2.5 mass in the absence of inversions and up to 69% during strong inversions. Also, the formation of ammonium nitrate is nitric acid limited. Overall, the lower boundary layer in the Salt Lake Valley appears to be oxidant and volatile organic carbon (VOC) limited with respect to ozone formation. The most effective way to reduce ammonium nitrate secondary particle formation during the inversions period is to reduce NO(x) emissions. However, a decrease in NO(x) will increase ozone concentrations. A better definition of the complete ozone isopleths would better inform this decision. Implications: Monitoring of air pollution constituents in Salt Lake City, UT, during periods in which PM2.5 concentrations exceeded the NAAQS, reveals that secondary aerosol formation for this region is NO(x) limited. Therefore, NO(x) emissions should be targeted in order to reduce secondary particle formation and PM2.5. Data also indicate that the highest concentrations of sulfur dioxide are associated with winds from the north-northwest, the location of several small refineries.

  2. Fabrication and wear test of a continuous fiber/particulate composite total surface hip replacement

    NASA Technical Reports Server (NTRS)

    Roberts, J. C.; Ling, F. F.; Jones, W. R., Jr.

    1981-01-01

    Continuous fiber woven E-glass composite femoral shells having the ame elastic properties as bone were fabricated. The shells were then encrusted with filled epoxy wear resistant coatings and run dry against ultrahigh molecular weight polyethylene acetabular cups in 42,000 and 250,000 cycle were tests on a total hip simulator. The tribological characteristics of these shells atriculating with the acetabular cups are comparable to a vitallium bal articulating with an ultrahigh molecular weight polyethylene cup.

  3. Size and composition distribution of fine particulate matter emitted from wood burning, meat charbroiling, and cigarettes

    SciTech Connect

    Kleeman, M.J.; Schauer, J.J.; Cass, G.R.

    1999-10-15

    A dilution source sampling system is augmented to measure the size-distributed chemical composition of fine particle emissions from air pollution sources. Measurements are made using a laser optical particle counter (OPC), a differential mobility analyzer/condensation nucleus counter (DMA/CNC) combination, and a pair of microorifice uniform deposit impactors (MOUDIs). The sources tested with this system include wood smoke (pine, oak, eucalyptus), meat charbroiling, and cigarettes. The particle mass distributions from all wood smoke sources have a single mode that peaks at approximately 0.1--0.2 {micro}m particle diameter. The smoke from meat charbroiling shows a major peak in the particle mass distribution at 0.1--0.2 {micro}m particle diameter, with some material present at larger particle sizes. Particle mass distributions from cigarettes peak between 0.3 and 0.4 {micro}m particle diameter. Chemical composition analysis reveals that particles emitted from the sources tested here are largely composed of organic compounds. Noticeable concentrations of elemental carbon are found in the particles emitted from wood burning. The size distributions of the trace species emissions from these sources also are presented, including data for Na, K, Ti, Fe, Br, Ru, Cl, Al, Zn, Ba, Sr, V, Mn, Sb, La, Ce, as well as sulfate, nitrate, and ammonium ion when present in statistically significant amounts. These data are intended for use with air quality models that seek to predict the size distribution of the chemical composition of atmospheric fine particles.

  4. Influence of carbon nanotubes on the properties of epoxy based composites reinforced with a semicrystalline thermoplastic

    NASA Astrophysics Data System (ADS)

    Díez-Pascual, A.; Shuttleworth, P.; Gónzalez-Castillo, E.; Marco, C.; Gómez-Fatou, M.; Ellis, G.

    2014-08-01

    Novel ternary nanocomposites based on a thermoset (TS) system composed of triglycidyl p-aminophenol (TGAP) epoxy resin and 4,4'-diaminodiphenylsulfone (DDS) curing agent incorporating 5 wt% of a semicrystalline thermoplastic (TP), an ethylene/1-octene copolymer, and 0.5 or 1.0 wt% multi-walled carbon nanotubes (MWCNTs) have been prepared via physical blending and curing. The influence of the TP and the MWCNTs on the curing process, morphology, thermal and mechanical properties of the hybrid nanocomposites has been analyzed. Different morphologies evolved depending on the CNT content: the material with 0.5 wt% MWCNTs showed a matrix-dispersed droplet-like morphology with well-dispersed nanofiller that selectively located at the TS/TP interphase, while that with 1.0 wt% MWCNTs exhibited coarse dendritic TP areas containing agglomerated MWCNTs. Although the cure reaction was accelerated in its early stage by the nanofillers, curing occurred at a lower rate since these obstructed chain crosslinking. The nanocomposite with lower nanotube content displayed two crystallization peaks at lower temperature than that of pure TP, while a single peak appearing at similar temperature to that of TP was observed for the blend with higher nanotube loading. The highest thermal stability was found for TS/TP (5.0 wt%)/MWCNTs (0.5 wt%), due to a synergistic barrier effect of both TP and the nanofiller. Moreover, this nanocomposite displayed the best mechanical properties, with an optimal combination of stiffness, strength and toughness. However, poorer performance was found for TS/TP (5.0 wt%)/MWCNTs (1.0 wt%) due to the less effective reinforcement of the agglomerated nanotubes and the coalescence of the TP particles into large areas. Therefore, finely tuned morphologies and properties can be obtained by adjusting the nanotube content in the TS/TP blends, leading to high-performance hybrid nanocomposites suitable for structural and high-temperature applications.

  5. Physical properties, chemical composition, and cloud forming potential of particulate emissions from a marine diesel engine at various load conditions.

    PubMed

    Petzold, A; Weingartner, E; Hasselbach, J; Lauer, P; Kurok, C; Fleischer, F

    2010-05-15

    Particulate matter (PM) emissions from one serial 4-stroke medium-speed marine diesel engine were measured for load conditions from 10% to 110% in test rig studies using heavy fuel oil (HFO). Testing the engine across its entire load range permitted the scaling of exhaust PM properties with load. Emission factors for particle number, particle mass, and chemical compounds were determined. The potential of particles to form cloud droplets (cloud condensation nuclei, CCN) was calculated from chemical composition and particle size. Number emission factors are (3.43 +/- 1.26) x 10(16) (kg fuel)(-1) at 85-110% load and (1.06 +/- 0.10) x 10(16) (kg fuel)(-1) at 10% load. CCN emission factors of 1-6 x 10(14) (kg fuel)(-1) are at the lower bound of data reported in the literature. From combined thermal and optical methods, black carbon (BC) emission factors of 40-60 mg/(kg fuel) were determined for 85-100% load and 370 mg/(kg fuel) for 10% load. The engine load dependence of the conversion efficiency for fuel sulfur into sulfate of (1.08 +/- 0.15)% at engine idle to (3.85 +/- 0.41)% at cruise may serve as input to global emission calculations for various load conditions.

  6. Pigments, elemental composition (C, N, P, Si) and stoichiometry of particulate matter, in the naturally iron fertilized region of Kerguelen in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Lasbleiz, M.; Leblanc, K.; Blain, S.; Ras, J.; Cornet-Barthaux, V.; Hélias Nunige, S.; Quéguiner, B.

    2014-06-01

    The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October-November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m-2 for chlorophyll a, 314 to 744 mmol m-2 for biogenic silica (BSi), 1106 to 2268 mmol m-2 for particulate organic carbon, 215 to 436 mmol m-2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m-2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the Polar Front Zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size-fractionation and HPLC pigment signatures, whereas the iron-limited reference area was associated to a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (respectively 0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9) in the iron-fertilized areas compared to the iron-limited reference station (respectively 0.13, 1.1, 5.8). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From POC, PON, and BSi evolutions, we showed that the elemental composition of the particulate matter also varies at the seasonal scale. This temporal evolution followed changes of the

  7. Carbon and nitrogen isotopic compositions of particulate organic matter in four large river systems across the United States

    USGS Publications Warehouse

    Kendall, C.; Silva, S.R.; Kelly, V.J.

    2001-01-01

    Riverine particulate organic matter (POM) samples were collected bi-weekly to monthly from 40 sites in the Mississippi, Colorado, Rio Grande, and Columbia River Basins (USA) in 1996-97 and analysed for carbon and nitrogen stable isotopic compositions. These isotopic compositions and C : N ratios were used to identify four endmember sources of POM: Plankton, fresh terrestrial plant material, aquatic plants, and soil organic material. This large-scale study also incorporated ancillary chemical and hydrologic data to refine and extend the interpretations of POM sources beyond the source characterizations that could be done solely with isotopic and elemental ratios. The ancillary data were especially useful for differentiating between seasonal changes in POM source materials and the effects of local nutrient sources and in-stream biogeochemical processes. Average values of ??13 C and C : N for all four river systems suggested that plankton is the dominant source of POM in these rivers, with higher percentages of plankton downstream of reservoirs. Although the temporal patterns in some rivers are complex, the low ??13C and C : N values in spring and summer probably indicate plankton blooms, whereas relatively elevated values in fall and winter are consistent with greater proportions of decaying aquatic vegetation and/or terrestrial material. Seasonal shifts in the ??13C of POM when the C : N remains relatively constant probably indicate changes in the relative rates of photosynthesis and respiration. Periodic inputs of plant detritus are suggested by C : N ratios >15, principally on the Columbia and Ohio Rivers. The ??15N and ??13C also reflect the importance of internal and external sources of dissolved carbon and nitrogen, and the degree of in-stream processing. Elevated ??15N values at some sites probably reflect inputs from sewage and/or animal waste. This information on the spatial and temporal variation in sources of POM in four major river systems should prove

  8. Biochemical composition of pico-, nano- and micro-particulate organic matter and bacterioplankton biomass in the oligotrophic Cretan Sea (NE Mediterranean)

    NASA Astrophysics Data System (ADS)

    Danovaro, Roberto; Dell'Anno, Antonio; Pusceddu, Antonio; Daniela Marrale; Della Croce, Norberto; Fabiano, Mauro; Tselepides, Anastasios

    2000-08-01

    The biochemical composition of different particle size classes (pico-, nano- and micro-particulate matter) and the bacterioplankton biomass were studied over an annual cycle in the Cretan Sea (South Aegean Sea, NE Mediterranean; from 40 to 1540 m depth) to investigate the origin, composition and fate of the suspended particles and to quantify bacterioplankton contribution to organic carbon pools. The oligotrophy of this system was indicated by the extremely low particulate lipid, protein and carbohydrate concentrations (4-15 times lower than in more productive systems). The biopolymeric carbon (BPC as the sum of lipid, protein and carbohydrate carbon) accounted for 80-100% of POC, suggesting the autochthonous origin of the particles. The most evident characteristic of this oligotrophic environment was the dominance of the pico-particles through all seasons, accounting for 43-45% of total carbohydrates, proteins and lipids. The proximate composition of the organic particles revealed the dominance of carbohydrates in all size-classes and highest values of the protein to carbohydrate ratio in the pico-particulate fraction. The relative proportion of the pico-, nano- and micro-particulate carbohydrates, proteins and lipids varied seasonally. The increase in the average particle size from February to September 95, probably as a result of aggregation, appeared to be related to the ‘thermal stability’ of the water column. The analysis of the vertical distribution of the three size classes revealed an increase in the pico fraction and a decrease in the larger components with increasing depth suggesting that nano- and micro-particles were being degraded and fragmented in the deeper water layers. Bacterial densities ranged from 1.1 to 8.8 x 10 8 cells l -1. Bacterial biomass accounted on average for more than 56% (up to 74%) of BPC and was by far, the most important living component. Bacterial-N accounted for a large proportion (>90%) of the protein nitrogen pool

  9. Characterisation of the organic composition of size segregated atmospheric particulate matter at traffic exposed and background sites in Madrid

    NASA Astrophysics Data System (ADS)

    Mirante, F.; Perez, R.; Alves, C.; Revuelta, M.; Pio, C.; Artiñano, B.; Nunes, T.

    2010-05-01

    The growing awareness of the impact of atmospheric particulate matter (PM) on climate, and the incompletely recognised but serious effects of anthropogenic aerosols on air quality and human health, have led to diverse studies involving almost exclusively the coarse or the fine PM fractions. However, these environmental effects, the PM formation processes and the source assignment depend greatly on the particle size distribution. The innovative character of this study consists in obtaining time series with a size-segregated detailed chemical composition of PM for differently polluted sites. In this perspective, a summer sampling campaign was carried out from 1 of June to 1 of July 2009. One of the sampling sites was located at a representative urban monitoring station (Escuelas Aguirre) belonging to the municipal network, located at a heavy traffic street intersection in downtown Madrid. Other sampling point was positioned within the CIEMAT area, located in the NW corner of the city, which can be considered an urban background or suburban site. Particulate matter was sampled with high volume cascade impactors at 4 size stages: 10-2.5, 2.5-0.95, 0.95-0.45 and < 0.45 µm. Daily sampling was carried out on quartz fibre filters. Based on meteorological conditions and PM mass concentrations, each one of the 7 groups of filters collected during the first week were combined with the corresponding filters of the third week. The same procedure was undertaken with samples of the second and fourth weeks. Filters of 0.95-0.45 and < 0.45 µm were pooled to obtain the PM0.95 organic composition. The PM size-segregated samples were subjected to organic analysis by gas chromatography-mass spectrometry (GC-MS), after solvent extraction of filters and an appropriate derivatisation technique. Besides the homologous compound series of organic classes (e.g. n-alkanes, n-alkanols and n-alkanoic acids), special attention was given to the determination of specific molecular markers for

  10. Fine particulate pollution in the Nanjing northern suburb during summer: composition and sources.

    PubMed

    An, Junlin; Duan, Qing; Wang, Honglei; Miao, Qing; Shao, Ping; Wang, Jian; Zou, Jianan

    2015-09-01

    To understand the chemical composition characteristic of pollution in a northern suburb of Nanjing, particle samples were collected by two Andersen cascade impactors from May to July 2013. The positive matrix factorization version 3 (EPA-PMF 3.0) was applied to identify the source contribution of PM2.1 concentrations in the study area. Source categories were determined based on the chemical component abundances in the source profiles. Overall, results indicated that seven factors were obtained. The factors are identified as follows: (I) secondary aerosol, characterized by high concentrations of NH4 (+), NO3 (-), and SO4 (2-), accounting for 20.22 %; (II) metallurgical aerosol, characterized by high concentrations of Pb, Cd, and Zn, accounting for 6.71 %; (III) road dust, characterized by high concentrations of Mg, Ca, Na, Al, and Ba, accounting for 11.85 %; (IV) biomass burning, characterized by high concentrations of K(+), Na(+), Cl(-), and K, accounting for 10.17 %; (V) residual oil, characterized by high concentrations of V and Cr, accounting for 16.63 %; (VI) iron and steel industry, characterized by high concentrations of Mn and Fe, accounting for 9.48 %; and (VII) vehicle exhaust, characterized by high concentrations of organic carbon (OC), Mo, elemental carbon (EC) and K, accounting for 24.94 %.

  11. Gaseous and particulate composition of fresh and aged emissions of diesel, RME and CNG buses using Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Psichoudaki, Magda; Le Breton, Michael; Hallquist, Mattias; Watne, Ågot; Hallquist, Asa

    2016-04-01

    Urban air pollution is becoming a significant global problem, especially for large cities around the world. Traffic emissions contribute significantly to both elevated particle concentrations and to gaseous pollutants in cities. The latter also have the potential of forming more particulate mass via their photochemical oxidation in the atmosphere. The International Agency for Research on Cancer and the US EPA have characterised diesel exhausts as a likely human carcinogen that can also contribute to other health problems. In order to meet the challenges with increased transportation and enhanced greenhouse gas emissions, the European Union have decided on a 10% substitution of traditional fuels in the road transport sector by alternative fuels (e.g. biodiesel, CNG) before the year 2020. However, it is also important to study the influence of fuel switches on other primary pollutants as well as the potential to form secondary aerosol mass. This work focuses on the characterisation of the chemical composition of the gas and the condensed phase of fresh bus emissions during acceleration, in order to mimic the exhaust plume that humans would inhale under realistic conditions. In addition, photochemical aging of the exhaust emissions was achieved by employing a Potential Aerosol Mass (PAM) flow reactor, allowing the characterization of the composition of the corresponding aged emissions. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the chamber. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in these measurements corresponded to a range from 4 to 8 days in the atmosphere. During June and July 2015, a total of 29 buses, 5 diesel, 13 CNG and 11 RME (rapeseed methyl ester), were tested in two different locations with limited influence from other types of emissions and traffic

  12. Airborne particulate endocrine disrupting compounds in China: Compositions, size distributions and seasonal variations of phthalate esters and bisphenol A

    NASA Astrophysics Data System (ADS)

    Li, Jianjun; Wang, Gehui

    2015-03-01

    Phthalate esters and bisphenol A (BPA) are endocrine disrupting compounds (EDCs) and ubiquitously occur in the environment. In the past decade we have characterized atmospheric organic aerosols from various environments (e.g., urban, rural, mountain and marine) of East Asia on a molecular level, but not investigated EDCs in the samples. In the current study we re-analyzed our database for concentrations, compositions and size distributions of phthalates and BPA and compared with those in the literature to improve the understanding on air pollution status in China. Our results showed that airborne particulate phthalates and BPA are 63-1162 ng m- 3 and 1.0-20 ng m- 3 in the urban regions in China, respectively, being one to two orders of magnitude higher than those in the developed countries. Among the detected phthalates in Chinese urban areas, bis(2-ethylhexyl) phthalate (BEHP) is the predominant congener, contributing to 23-79% (ave. 53 ± 15%) of the total phthalates. Concentrations of phthalates and bisphenol A in Shanghai and Xi'an (two mega-cities in China) in 2009 were 3-84% lower than those in 2003, probably indicating a positive effect of the government's air pollution control in the recent years. Phthalates are higher in summer than in winter, because they are not chemically bonded to the polymeric matrix and more easily evaporate into the air under higher temperature conditions. Based on the size distribution observation, we found that diisobutyl and dibutyl phthalates mainly exist in coarse particles because of high volatilities, in contrast to BEHP and BPA, which are dominant in fine particles due to less volatility. Our results also indicate that BPA is mostly derived from the open burning of solid waste while phthalates are derived from both direct evaporation from the matrix and solid waste combustion.

  13. Source apportionment of ambient fine particulate matter in Dearborn, Michigan, using hourly resolved PM chemical composition data.

    PubMed

    Pancras, Joseph Patrick; Landis, Matthew S; Norris, Gary A; Vedantham, Ram; Dvonch, J Timothy

    2013-03-15

    High time-resolution aerosol sampling was conducted for one month during July-August 2007 in Dearborn, MI, a non-attainment area for fine particulate matter (PM2.5) National Ambient Air Quality Standards (NAAQS). Measurements of more than 30 PM2.5 species were made using a suite of semi-continuous sampling and monitoring instruments. Dynamic variations in the sub-hourly concentrations of source 'marker' elements were observed when discrete plumes from local sources impacted the sampling site. Hourly averaged PM2.5 composition data for 639 samples were used to identify and apportion PM2.5 emission sources using the multivariate receptor modeling techniques EPA Positive Matrix Factorization (PMF) v4.2 and EPA Unmix v6.0. Source contribution estimates from PMF and Unmix were then evaluated using the Sustained Wind Instance Method (SWIM), which identified plausible source origins. Ten sources were identified by both PMF and Unmix: (1) secondary sulfate, (2) secondary nitrate characterized by a significant diurnal trend, (3) iron and steel production, (4) a potassium-rich factor attributable to iron/steel slag waste processing, (5) a cadmium-rich factor attributable to incineration, (6) an oil refinery characterized by La/Ce>1 specific to south wind, (7) oil combustion, (8) coal combustion, (9) motor vehicles, and (10) road dust enriched with organic carbon. While both models apportioned secondary sulfate, oil refinery, and oil combustion PM2.5 masses closely, the mobile and industrial source apportionments differed. Analyses were also carried out to help infer time-of-day variations in the contributions of local sources.

  14. Spatio-temporal variability of airborne bacterial communities and their correlation with particulate matter chemical composition across two urban areas.

    PubMed

    Gandolfi, I; Bertolini, V; Bestetti, G; Ambrosini, R; Innocente, E; Rampazzo, G; Papacchini, M; Franzetti, A

    2015-06-01

    The study of spatio-temporal variability of airborne bacterial communities has recently gained importance due to the evidence that airborne bacteria are involved in atmospheric processes and can affect human health. In this work, we described the structure of airborne microbial communities in two urban areas (Milan and Venice, Northern Italy) through the sequencing, by the Illumina platform, of libraries containing the V5-V6 hypervariable regions of the 16S rRNA gene and estimated the abundance of airborne bacteria with quantitative PCR (qPCR). Airborne microbial communities were dominated by few taxa, particularly Burkholderiales and Actinomycetales, more abundant in colder seasons, and Chloroplasts, more abundant in warmer seasons. By partitioning the variation in bacterial community structure, we could assess that environmental and meteorological conditions, including variability between cities and seasons, were the major determinants of the observed variation in bacterial community structure, while chemical composition of atmospheric particulate matter (PM) had a minor contribution. Particularly, Ba, SO4 (2-) and Mg(2+) concentrations were significantly correlated with microbial community structure, but it was not possible to assess whether they simply co-varied with seasonal shifts of bacterial inputs to the atmosphere, or their variation favoured specific taxa. Both local sources of bacteria and atmospheric dispersal were involved in the assembling of airborne microbial communities, as suggested, to the one side by the large abundance of bacteria typical of lagoon environments (Rhodobacterales) observed in spring air samples from Venice and to the other by the significant effect of wind speed in shaping airborne bacterial communities at all sites.

  15. Proinflammatory and cytotoxic effects of Mexico City air pollution particulate matter in vitro are dependent on particle size and composition.

    PubMed

    Osornio-Vargas, Alvaro R; Bonner, James C; Alfaro-Moreno, Ernesto; Martínez, Leticia; García-Cuellar, Claudia; Ponce-de-León Rosales, Sergio; Miranda, Javier; Rosas, Irma

    2003-08-01

    Exposure to urban airborne particulate matter (PM) is associated with adverse health effects. We previously reported that the cytotoxic and proinflammatory effects of Mexico City PM10 (less than or equal to 10 micro m mean aerodynamic diameter) are determined by transition metals and endotoxins associated with these particles. However, PM2.5 (less than or equal to 2.5 micro m mean aerodynamic diameter) could be more important as a human health risk because this smaller PM has the potential to reach the distal lung after inhalation. In this study, we compared the cytotoxic and proinflammatory effects of Mexico City PM10 with those of PM2.5 using the murine monocytic J774A.1 cell line in vitro. PMs were collected from the northern zone or the southeastern zone of Mexico City. Elemental composition and bacterial endotoxin on PMs were measured. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) production by J774A.1 cells was measured in the presence or absence of recombinant endotoxin-neutralizing protein (rENP). Both northern and southeastern PMs contained endotoxin and a variety of transition metals. Southeastern PM10 contained the highest endotoxin levels, 2-fold higher than that in northern PM10. Northern and southeastern PM2.5 contained the lowest endotoxin levels. Accordingly, southeastern PM10 was the most potent in causing secretion of the proinflammatory cytokines TNF-alpha and IL-6. All PM2.5 and PM10 samples caused cytotoxicity, but northern PMs were the most toxic. Cytokine secretion induced by southeastern PM10 was reduced 50-75% by rENP. These results indicate major differences in PM10 and PM2.5. PM2.5 induces cytotoxicity in vitro through an endotoxin-independent mechanism that is likely mediated by transition metals. In contrast, PM10 with relatively high levels of endotoxin induces proinflammatory cytokine release via an endotoxin-dependent mechanism.

  16. Characterization of Forty Seven Years of Particulate Chemical Composition in the Finnish Arctic

    NASA Astrophysics Data System (ADS)

    Laing, James

    emissions inventories. Pb concentrations at Kevo have dramatically decreased (92%) in the past 47 years due to the reduced use of leaded gasoline in automobiles. Non sea salt SO4 concentrations were found to have a very similar trend to European and Former Soviet Union SO2 emissions. SO4 concentrations declined dramatically in the early 1990s a result of the collapse of the Soviet Union. Potential source contribution function (PSCF) analysis was used to estimate source locations of the species. PSCF plots for anthropogenic species (V, Cd, Mn, Mo, Sb, Tl, W, and SO4) suggest source areas predominantly in Eastern Europe, European Russia, and the Baltics. Markers of stationary fuel combustion (V, Mn, Mo, Sb, Se, Tl, and SO4) also pointed towards possible source regions in the Pechora Basin and Ural industrial areas in Russia, and near gas and oil fields in western Kazakhstan. Methane sulfonic acid (MSA) is marker of marine planktonic algae. MSA concentrations at Kevo peak from May to July and have estimated source locations in the Barents, Norwegian, and Greenland Seas, coinciding with warmer waters and increased biogenic activity. Using monthly averages from June and Jul, MSA concentrations were found to be positively correlated (r2 = 0.200; p < 0.001) with sea surface temperature anomalies in the surrounding seas and negatively (r2 = 0.280; p = 0.0018) with sea ice extent. The chemical composition dataset was analyzed by Positive Matrix Factorization (PMF5). The entire dataset (1964-2010) was modeled as well as three separate time periods, 1964-1978, 1979-1990, and 1991-2010. The dataset was split in 1979 due to a change from Whatman 42 cellulose filters to a glass fiber filters, and in 1990 due to drops in concentrations related to the economic collapse of the Soviet Union. Two factors representing non-ferrous metal smelters were found for all time periods. One factor was dominated by Cu and the other by Ni and Co. Each of the time periods contained a factor describing

  17. Epoxy-based production of wind turbine rotor blades: occupational dermatoses.

    PubMed

    Pontén, A; Carstensen, O; Rasmussen, K; Gruvberger, B; Isaksson, M; Bruze, M

    2004-06-01

    Occupational dermatoses were investigated in a factory producing rotor blades for wind turbines by an epoxy-based process. In a blinded study design, 603 workers were first interviewed and thereafter clinically examined. Based on a history of work-related skin disease, clinical findings of dermatitis, or both, 325 (53.9%) of the workers were patch tested with a specially profiled occupational patch-test series and the European standard patch-test series. Calculated on all investigated workers, 17.1% of the workers were diagnosed with occupational dermatoses caused by work. Occupational allergic contact dermatitis was found in 10.9% of the workers. The estimated frequency of irritant contact dermatitis caused by work was 6.1%. Dermatitis on the hands was associated with contact allergy to epoxy resin (P = 0.017). The number of days on leave before the clinical examination was negatively associated with the presence of dermatitis (P = 0.001). Among workers employed 7-12 months, the frequency of occupational contact allergy was higher than that among workers employed for

  18. Chemical compositions responsible for inflammation and tissue damage in the mouse lung by coarse and fine particulate samples from contrasting air pollution in Europe.

    PubMed

    Happo, Mikko S; Hirvonen, Maija-Riitta; Halinen, Arja I; Jalava, Pasi I; Pennanen, Arto S; Sillanpaa, Markus; Hillamo, Risto; Salonen, Raimo O

    2008-11-01

    Inflammation is regarded as an important mechanism in mortality and morbidity associated with exposures of cardiorespiratory patients to urban air particulate matter. We investigated the association of the chemical composition and sources of urban air fine (PM(2.5-0.2)) and coarse (PM(10-2.5)) particulate samples with the inflammatory activity in the mouse lung. The particulate samples were collected during selected seasons in six European cities using a high-volume cascade impactor. Healthy C57BL/6J mice were intratracheally instilled with a single dose (10 mg/kg) of the particulate samples. At 4, 12, and 24 h after the exposure, the lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: cell number, total protein, and cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6, and KC). Dicarboxylic acids and transition metals, especially Ni and V, in PM(2.5-0.2) correlated positively and some secondary inorganic ions (NO3(-), NH4(+)) negatively with the inflammatory activity. Total organic matter and SO4(2-) had no consistent correlations. In addition, the soil-derived constituents (Ca2+, Al, Fe, Si) showed positive correlations with the PM(2.5-0.2)-induced inflammatory activity, but their role in PM(10-2.5) remained obscure, possibly due to largely undefined biogenic material. Markers of poor biomass and coal combustion, i.e., monosaccharide anhydrides and As, were associated with elevated PAH contents in PM(2.5-0.2) and a consistent immunosuppressive effect. Overall, our results support epidemiological findings that the local sources of incomplete combustion and resuspended road dust are important in urban air particulate pollution-related health effects.

  19. Effect of biodiesel fuel on "real-world", nonroad heavy duty diesel engine particulate matter emissions, composition and cytotoxicity.

    PubMed

    Martin, Nathan; Lombard, Melissa; Jensen, Kirk R; Kelley, Patrick; Pratt, Tara; Traviss, Nora

    2017-05-15

    Biodiesel is regarded by many as a "greener" alternative fuel to petroleum diesel with potentially lower health risk. However, recent studies examining biodiesel particulate matter (PM) characteristics and health effects are contradictive, and typically utilize PM generated by passenger car engines in laboratory settings. There is a critical need to analyze diesel and biodiesel PM generated in a "real-world" setting where heavy duty-diesel (HDD) engines and commercially purchased fuel are utilized. This study compares the mass concentrations, chemical composition and cytotoxicity of real-world PM from combustion of both petroleum diesel and a waste grease 20% biodiesel blend (B20) at a community recycling center operating HDD nonroad equipment. PM was analyzed for metals, elemental/organic carbon (EC/OC), polycyclic aromatic hydrocarbons (PAHs), and nitro-polycyclic aromatic hydrocarbons (N-PAHs). Cytotoxicity in a human lung epithelial cell line (BEAS-2B) following 24h exposure to the real-world particles was also evaluated. On average, higher concentrations for both EC and OC were measured in diesel PM. B20 PM contained significantly higher levels of Cu and Mo whereas diesel PM contained significantly higher concentrations of Pb. Principal component analysis determined Mo, Cu, and Ni were the metals with the greatest loading factor, suggesting a unique pattern related to the B20 fuel source. Total PAH concentration during diesel fuel use was 1.9 times higher than during B20 operations; however, total N-PAH concentration was 3.3 times higher during B20 use. Diesel PM cytotoxicity was 8.5 times higher than B20 PM (p<0.05) in a BEAS-2B cell line. This study contributes novel data on real-world, nonroad engine sources of metals, PAH and N-PAH species, comparing tailpipe PM vs. PM collected inside the equipment cabin. Results suggest PM generated from burning petroleum diesel in nonroad engines may be more harmful to human health, but the links between exposure

  20. Annual cycle and spatial trends in fatty acid composition of suspended particulate organic matter across the Beaufort Sea shelf

    NASA Astrophysics Data System (ADS)

    Connelly, Tara L.; Businski, Tara N.; Deibel, Don; Parrish, Christopher C.; Trela, Piotr

    2016-11-01

    Fatty acid profiles of suspended particulate organic matter (POM) were determined over an annual cycle (September 2003 to August 2004) on the Beaufort Sea shelf, Canadian Arctic. Special emphasis was placed on the nutritional quality of the fatty acid pool available to zooplankton by examining spatial and temporal patterns in the proportions of total polyunsaturated fatty acids (PUFA) and the essential fatty acids 22:6n-3 (DHA) and 20:5n-3 (EPA). EPA and DHA were the two most abundant PUFA throughout the study period. A log-ratio multivariate (LRA) analysis revealed strong structure in fatty acid profiles related to season and depth. Dominant fatty acids accounting for the observed trend included 18:5n-3, 18:4n-3, 16:1n-7, 20:5n-3, 18:0 and 20:3n-3. We observed a shift in fatty acid profiles from summer to autumn (e.g., from 16:1n-7 and EPA to 18:5n-3 and 18:4n-3) that likely corresponded to a shift in the relative importance of diatoms versus dinoflagellates, prymnesiophytes and/or prasinophytes to the POM pool. Fatty acid composition during winter was dominated by more refractory saturated fatty acids. A surprising finding was the depth and seasonal trend of 20:3n-3, which was higher in winter, aligned with 18:0 in the LRA, but behaved differently than other n-3 PUFA. We interpret fatty acid profiles during summer to be predominantly driven by phytoplankton inputs, whereas fatty acid profiles in winter were dominated by fatty acids that were left over after consumption and/or were generated by heterotrophs. The highest diatom inputs (EPA, the diatom fatty acid marker), n-3/n-6 ratios, and C16 PUFA index were located in an upwelling region off Cape Bathurst. This study is the first annual time series of fatty acid profiles of POM in Arctic seas, expanding our knowledge of the composition of POM throughout the dark season.

  1. The effect of matrix temper on particulate integrity in an Al/Al[sub 2]O[sub 3] metal matrix composite

    SciTech Connect

    Ferry, M.; Munroe, P.R. . School of Materials Science and Engineering)

    1994-07-15

    Aluminium-based particulate metal-matrix composites (PMMC's) are being developed for application in both the aerospace and automotive industries. The near-isotropic properties of these materials allow them to be processed through the same conventional thermomechanical routes that are applied to unreinforced aluminium alloys. However, the microstructural behavior of these materials during such treatments has not been widely studied. It is also relevant to note that matrix prior to processing may strongly affect the behavior of these alloys during deformation. This paper describes the microstructural development during cold work of a PMMC consisting of a 2xxx series alloy matrix, reinforced with alumina particles, heat treated to two different starting tempers. Of particular importance is the effect of matrix temper on the integrity of the alumina particulates.

  2. The Application of a Representative Volume Element (RVE) Model for the Prediction of Rice Husk Particulate-Filled Polymer Composite Properties

    NASA Astrophysics Data System (ADS)

    Pochanard, Pandhita

    Polymer composite is one of the most widely used materials with application in multiple industries. However, its versatility and subsequent rise in consumption have prompted an increase in research on alternative materials to address the associated environmental concerns. The forefront of this investigation is on the potential use of biocomposite materials as a more sustainable replacement to the traditional polymer composite. Consequently, the ability to apply a theoretical model capable of replicating the microstructures of particulate-filled composite would make a very powerful analytical tool for material design. To address these requirements, this thesis applies a representative volume element (RVE) model for the investigation on the potential use of rice husk particulate-filled polymer composite as alternative material in non-critical application. In this work, rice husk powder (RHP) was used with epoxy for the fabrication of biocomposite samples with 0%, 10% and 30% RHP volume percentage. It was observed that a 10% increase in RHP did not affect the composite elastic property, but led to 15% and 20% decrease in yield stress and tensile strength, respectively. Further increase in RHP to 30% volume percentage also led to 8%, 21% and 28% reduction in Young's modulus, yield stress and tensile strength, respectively. Additionally, the material's responses to uniaxial loading predicted by the RVE model were found to be in reasonable agreement with the analytical and experimental results. No coupling agent was used in this study. The results of this present study suggested that rice husk powder could be used to reduce the composite raw material costs by replacing the more expensive polymer content with agricultural waste products without significant compromise to the composite's mechanical properties.

  3. Stable Carbon Isotope Composition and Dynamics of Particulate Organic Carbon in the Basin of the Ganga-Brahmaputra River

    NASA Astrophysics Data System (ADS)

    Aucour, A.; France-Lanord, C.; Pedoja, K.; Piersson-Wickmann, A.; Sheppard, S.

    2004-05-01

    The Ganga-Brahmaputra River ranks first for sediment transport among world rivers, with high erosion rates in the Himalayan range driving the high suspended flux. The organic carbon (OC) burial flux in the Bengal fan has been estimated to be around 1.1 x 1012 molC yr-1 for the Neogene and could represent about 10% of the global burial flux of OC in continental margins. This stresses the importance of assessing the sources of the organic matter in the Himalayan watersheds and the chemical processing of organic matter on the flood-plain. To follow the dynamics of particulate OC, we used natural 13C-labelling of OC, which is essentially linked to the variable proportion of C3- and C4- plants on the watersheds, together with the mineralogical, chemical and isotopic (ɛ Nd) data of the associated silicates. The stable isotope compositions of OC were measured (1) in bedrocks, soils, and river sediments from an Himalayan watershed (Narayani River, Nepal), (2) in river sediments at several outflows of the range, and (3) in soils and river sediments on the Bangladeshi flood-plain. In the watershed of the Narayani River, the δ 13C values of OC range from 26.3 to 22‰ for the bank sediments and from 24.2 to 22‰ for the suspended sediments. They present a narrow range of values around 24‰ at the outflow of the Himalayan range. They are less negative than those of OC in forest soils, hence indicating a significant contribution from the deforested, subtropical zone. On the Bangladesh flood-plain, sediments from the Ganga and Brahmaputra Rivers are enriched in 13C (with δ 13C values around 22.5‰ ) relative to those collected at the range's outflow. This indicates addition of organic matter derived from the mixed C3-C4 biomass on the flood-plain. In sediments of the Ganga and Brahmaputra Rivers, the clay-size fraction is depleted in 13C relative to the bulk sediment. A possible explanation is that the organic matter associated with the clay-size fraction is essentially

  4. Proinflammatory and cytotoxic effects of Mexico City air pollution particulate matter in vitro are dependent on particle size and composition.

    PubMed Central

    Osornio-Vargas, Alvaro R; Bonner, James C; Alfaro-Moreno, Ernesto; Martínez, Leticia; García-Cuellar, Claudia; Ponce-de-León Rosales, Sergio; Miranda, Javier; Rosas, Irma

    2003-01-01

    Exposure to urban airborne particulate matter (PM) is associated with adverse health effects. We previously reported that the cytotoxic and proinflammatory effects of Mexico City PM10 (less than or equal to 10 micro m mean aerodynamic diameter) are determined by transition metals and endotoxins associated with these particles. However, PM2.5 (less than or equal to 2.5 micro m mean aerodynamic diameter) could be more important as a human health risk because this smaller PM has the potential to reach the distal lung after inhalation. In this study, we compared the cytotoxic and proinflammatory effects of Mexico City PM10 with those of PM2.5 using the murine monocytic J774A.1 cell line in vitro. PMs were collected from the northern zone or the southeastern zone of Mexico City. Elemental composition and bacterial endotoxin on PMs were measured. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) production by J774A.1 cells was measured in the presence or absence of recombinant endotoxin-neutralizing protein (rENP). Both northern and southeastern PMs contained endotoxin and a variety of transition metals. Southeastern PM10 contained the highest endotoxin levels, 2-fold higher than that in northern PM10. Northern and southeastern PM2.5 contained the lowest endotoxin levels. Accordingly, southeastern PM10 was the most potent in causing secretion of the proinflammatory cytokines TNF-alpha and IL-6. All PM2.5 and PM10 samples caused cytotoxicity, but northern PMs were the most toxic. Cytokine secretion induced by southeastern PM10 was reduced 50-75% by rENP. These results indicate major differences in PM10 and PM2.5. PM2.5 induces cytotoxicity in vitro through an endotoxin-independent mechanism that is likely mediated by transition metals. In contrast, PM10 with relatively high levels of endotoxin induces proinflammatory cytokine release via an endotoxin-dependent mechanism. PMID:12896848

  5. Source Apportionment of Ambient Fine Particulate Matter in Dearborn, Michigan, using Hourly Resolved PM Chemical Composition Data

    EPA Science Inventory

    High time-resolution aerosol sampling was conducted for one month during July–August 2007 in Dearborn, MI, a non-attainment area for fine particulate matter (PM2.5) National Ambient Air Quality Standards (NAAQS). Measurements of more than 30 PM2.5 species were made using a suite o...

  6. DISTRIBUTION AND COMPOSITION OF DISSOLVED AND PARTICULATE ORGANIC CARBON IN NORTHERN SAN FRANCISCO BAY DURING LOW FRESHWATER FLOW CONDITIONS

    EPA Science Inventory

    The distribution of dissolved and particulate organic matter was studied in northern San Francisco Bay on seven dates during declining flow conditions from April to October 1996. Measurements were made at 3 to 11 stations (usually 8) along the salinity gradient from the Sacrament...

  7. Experimental Comparison of the Effects of Nanometric and Micrometric Particulates on the Tensile Properties and Fracture Behavior of Al Composites at Room and Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Ahmed, Adnan; Neely, Andrew J.; Shankar, Krishna

    2011-03-01

    This article studies the influence of nanometric (n-SiCp) and micrometric-scale SiC particulates ( μ-SiCp) on the tensile properties of the Al 7075 alloy. The unreinforced Al and its composites were synthesized using the powder metallurgy (P/M) route and were tested uniaxially in tension at both room and elevated temperatures. Aging behavior was studied to observe any effect of the reinforcement on the aging kinetics and hardness of the composites. X-ray diffraction was performed to determine the crystal structures of the raw materials and any reaction phase formed in the composites. The n-SiCp were not dispersed uniformly in the Al matrix and clustered mainly at the grain boundaries. The stiffness of the composites increased and the ductility decreased with an increase in the volume fraction of the n-SiCp. The n-SiCp proved to be a better reinforcement than the traditional μ-SiCp in terms of imparting higher ductility to the composite. Fractography and microscopy using optical, scanning electron, and transmission electron microscopes were performed for failure and microstructural analysis of all the materials. At room temperature, the fracture altered from ductile in the unreinforced Al to brittle in the composites. At an elevated temperature, the fracture mechanism transformed from brittle to ductile rupture in the composites.

  8. Fabrication of Nano-SiC Particulate Reinforced Mg-8Al-1Sn Composites by Powder Metallurgy Combined with Hot Extrusion

    NASA Astrophysics Data System (ADS)

    Li, Chuan-Peng; Wang, Zhi-Guo; Wang, Hui-Yuan; Zhu, Xian; Wu, Min; Jiang, Qi-Chuan

    2016-11-01

    Nano-SiC particulates (n-SiCp) reinforced Mg-8Al-1Sn (AT81) composites with different volume fractions (0, 0.25, 0.5 and 1.0 vol.%) were fabricated by powder metallurgy process (P/M) combined with hot extrusion. The mechanical properties of the composite increased as the n-SiCp content increased until the n-SiCp content exceeded 0.5 vol.%, at which point they began to decrease. For this reason, the 0.5 vol.% n-SiCp/AT81 composite was considered optimal. The 0.2% offset yield strength (YS), ultimate tensile strength (UTS) and elongation (ɛ) of 0.5 vol.% n-SiCp/AT81 composites increased from 175, 318 MPa and 4.5% to 239, 381 MPa and 8.3%, respectively, compared to AT81. Both, the strength and plasticity of the 0.5 vol.% n-SiCp/AT81 composites were improved as well. The improvement in mechanical properties can be attributed to the progressively refined matrix grain size, relatively uniform distribution of n-SiCP and the well-bonded interfaces between n-SiCp and the matrix.

  9. Magnetic, magnetoelectric and dielectric behavior of CoFe2O4-Pb(Fe1/2Nb1/2)O3 particulate and layered composites

    NASA Astrophysics Data System (ADS)

    Kulawik, J.; Szwagierczak, D.; Guzdek, P.

    2012-09-01

    Magnetic, magnetoelectric and dielectric properties of multiferroic CoFe2O4-Pb(Fe1/2Nb1/2)O3 composites prepared as bulk ceramics were compared with those of tape cast and cofired laminates consisting of alternate ferrite and relaxor layers. X-ray diffraction analysis and Scanning Electron Microscope observations of ceramic samples revealed two-phase composition and fine grained microstructure with uniformly distributed ferrite and relaxor phases. High and broad maxima of dielectric permittivity attributed to dielectric relaxation were found for ceramic samples measured in a temperature range from -55 to 500 °C at frequencies 10 Hz-2 MHz. Magnetic hysteresis, zero-field cooled (ZFC) and field cooled (FC) curves, and dependencies of magnetization on temperature for both magnetoelectric composites were measured with a vibrating sample magnetometer in an applied magnetic field up to 80 kOe at 4-400 K. The hysteresis loops obtained for composites are typical of a mixture of the hard magnetic material with a significant amount of the paramagnet. The bifurcation of ZFC-FC magnetizations observed for both composites implies spin-glass behavior. Magnetoelectric properties at room temperature were investigated as a function of dc magnetic field (0.3-7.2 kOe) and frequency (10 Hz-10 kHz) of ac magnetic field. Both types of composites exhibit a distinct magnetoelectric effect. Maximum values of magnetoelectric coefficient attained for the layered composites exceed 200 mV/(cm Oe) and are almost three times higher than those for particulate composites.

  10. Combined analysis of trace elements and isotopic composition of particulate organic matter in suspended sediment to assess their origin and flux in a tropical disturbed watershed.

    PubMed

    Fernandes, Alexandre Martins; Hissler, Christophe; da Conceição, Fabiano Tomazini; Spatti Junior, Eder Paulo; Mortatti, Jefferson

    2016-11-01

    Approximately 40% of the volume of domestic sewage generated in the São Paulo State is untreated and released into water bodies, causing serious pollution problems that affect the water quality and especially the suspended sediments transported by rivers. Thus, this paper investigates the seasonal influence on the origin and fluxes of Cu, Co, Cr, Zn, Cd, Ni, Sc and particulate organic matter (POM) in sediments transported by a disturbed watershed in the São Paulo State, i.e. the Sorocaba River basin. POM was characterized using particulate organic carbon, particulate organic nitrogen, C:N ratio and δ(13)C and δ(15)N stable isotopic composition. Eight sample collections of fine suspended sediments (FSS) were carried out at the mouth of the Sorocaba River from July 2009 to May 2010. During the study period, the discharge rate followed the seasonal variation trend of the past 25 years. Zn was the most abundant trace element in the FSS, followed by Cr, Cu, Ni, Co, Sc and Cd. There was a higher concentration of trace elements during the dry season, except for Sc and Co, which did not vary seasonally. The POM showed the same trend, with higher concentrations during the dry season. The calculated enrichment factors and geoaccumulation index indicated that most of the trace elements are of geogenic origin, except for Zn, which showed significant anthropogenic contributions (55%). The elemental and isotopic analysis of C and N and C:N ratio indicated that the anthropogenic origin of POM found in the FSS is related mainly to domestic sewage (97%), while the significant correlation found between the concentrations of Zn and POM indicates that the main anthropogenic source of Zn is related to this domestic sewage. The FSS load transported during the study period was of 373,194 t y(-1), of which 87% occurred during the rainy season.

  11. Markers and influence of open biomass burning on atmospheric particulate size and composition during a major bonfire event

    NASA Astrophysics Data System (ADS)

    Vassura, Ivano; Venturini, Elisa; Marchetti, Sara; Piazzalunga, Andrea; Bernardi, Elena; Fermo, Paola; Passarini, Fabrizio

    2014-01-01

    This study aims to characterize PM from the open burning of bonfires as well as detect a series of useful tracer species for source apportionment studies. Total suspended particulate (TSP), PM10 and PM2.5 were collected before, during, and after St. Joseph's Eve (18th of March). On this day, several bonfires are lit throughout the study area. Levoglucosan (Lvg), OC, EC, PAHs, soluble ions, and some metals (Al, Cd, Cu, Ni, and Pb) have been determined in each fraction. Results show that the contamination of the area is similar to what is generally found in suburban areas. The fine fraction makes the highest contribution to PM. This fraction is mainly related to compounds composing the PM secondarily formed, while the coarser fractions are associated with natural matrices. The bonfire event is an important source of particulate. All the combustion markers determined in PM2.5 (EC, OC, PAHs (except for Flu and Pyr), K+, Cl-, and Lvg) register a higher concentration. Lvg/OC ratio confirms higher wood smoke emissions during these days. Both the concentration and the compound profile indicate a different origin of PAHs in the atmosphere. The highest concentration of K+ and OC in TSP confirm the contribution of open fire, as well, to this fraction, which can be ascribable mainly to combustion ash. Nitrates and sulphates also show a higher concentration in the PM10-TSP fraction. Surprisingly, there is also an increase in the concentration of components not usually considered combustion markers, i.e. Pb and Al in PM2.5. This is probably ascribable to their bioaccumulation. In conclusion, Lvg, OC, PAHs, Al, and Pb can be used together as specific markers of bonfires to identify this source of particulate matter.

  12. Detection of leachables and cytotoxicity after exposure to methacrylate- and epoxy-based root canal sealers in vitro.

    PubMed

    Lodienė, Greta; Kopperud, Hilde M; Ørstavik, Dag; Bruzell, Ellen M

    2013-10-01

    Root canal sealing materials may have toxic potential in vitro depending on the cell line, cytotoxicity assay, material chemistry, and degree of polymer curing. The aims of the present study were to detect leaching components from epoxy- or methacrylate-based root canal sealers and to investigate the degree of cytotoxicity after exposure to extracts from these materials. Qualitative determination of substances released from the materials was performed by gas- and liquid chromatography/mass spectrometry. Submandibular salivary gland acinar cell death (apoptosis/necrosis) was determined using a fluorescence staining/microscopy technique. The major leachable monomer from the epoxy-based material was bisphenol-A diglycidyl ether (BADGE), whereas leachables from the methacrylate-based materials were mainly triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and polyethyleneglycol dimethacrylate (PEGDMA). Exposure to diluted extracts of cured methacrylate-based materials caused a postexposure time-dependent increase in cell death. This effect was not demonstrated as a result of exposure to undiluted extract of cured epoxy-based material. Extracts of all fresh materials induced apoptosis significantly, but at lower dilutions of the epoxy- than the methacrylate-based materials. The degree of leaching, determined from the relative chromatogram peak heights of eluates from the methacrylate-based sealer materials, corresponded with the degree of cell death induced by extracts of these materials.

  13. The composition and flux of particulate and dissolved carbohydrates from the Rhône River into the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Panagiotopoulos, C.; Sempéré, R.; Para, J.; Raimbault, P.; Rabouille, C.; Charrière, B.

    2011-11-01

    Carbohydrates are important components of the carbon cycle and may be used as indicators of the origin and the diagenetic status of marine and terrestrial organic matter. Nevertheless, comprehensive studies of both particulate (PCHO) and dissolved (DCHO) carbohydrates in rivers are scarce, and the seasonal and interannual variability of these compounds in relationship to the bulk particulate (POM) and dissolved organic matter (DOM) is largely unknown. For the period 2007-2009, we sampled once per month POM and DOM and measured the total suspended matter (TSM), POM, DOM, PCHO, and DCHO for the Rhône River, which flows into the Mediterranean Sea. Using these measurements, we estimated for the above parameters annual fluxes for the period 2001-2010. The estimated carbohydrate fluxes averaged 0.061±0.043×1010 moles Cy-1 for PCHO and 0.041±0.0062×1010 moles Cy-1 DCHO, representing 8% and 7% of the annual flux of POC and DOC, respectively. During flood and low-water periods, POM variations were reflected into the PCHO pool, whereas this was not observed for DOC and DCHO, indicating a decoupling between particulate and dissolved organic matter. Our results also showed that flood and low-water periods may be differentiated using the ratios PCHO/DCHO and POC/DOC, which had a significant linear relationship. Based on the carbohydrate abundances in both the PCHO and DCHO pools, we conclude that this material mainly derives from allochthonous sources (vascular plants, bacteria and soils). Moreover, during flood events, an enrichment in mannose in POM was observed, probably reflecting an angiosperm source (leaves or grasses). By expanding our results to the northwestern Mediterranean Sea (Gulf of Lions), we found that the total organic carbon (TOC) fluxes of the Rhône River accounted for ~1% of the standing stock of seawater TOC. Considering that glucose is the most abundant carbohydrate in both particulate and dissolved organic matter pools (~33%), its annual flux in the

  14. The composition and flux of particulate and dissolved carbohydrates from the Rhone River into the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Panagiotopoulos, C.; Sempéré, R.; Para, J.; Raimbault, P.; Rabouille, C.; Charrière, B.

    2012-05-01

    Carbohydrates are important components of the carbon cycle and may be used as indicators of the origin and the diagenetic status of marine and terrestrial organic matter. Nevertheless, comprehensive studies of both particulate (PCHO) and dissolved (DCHO) carbohydrates in rivers are scarce, and the seasonal and interannual variability of these compounds in relationship to the bulk particulate (POM) and dissolved organic matter (DOM) is largely unknown. For the period 2007-2009, we sampled once per month POM and DOM and measured the total suspended matter (TSM), POM, DOM, PCHO, and DCHO for the Rhône River, which flows into the Mediterranean Sea. Using these measurements, we estimated for the above parameters annual fluxes for the period 2007-2009. The estimated carbohydrate fluxes averaged 0.064 ± 0.026 × 1010 moles C yr-1 for PCHO and 0.042 ± 0.008 × 1010 moles C yr-1 DCHO, representing 6 % and 7 % of the annual flux of POC and DOC, respectively. During flood and low-water periods, POM variations were reflected into the PCHO pool, whereas this was not observed for DOC and DCHO, indicating a decoupling between particulate and dissolved organic matter. Our results also showed that flood and low-water periods may be differentiated using the ratios PCHO/DCHO and POC/DOC, which had a significant relationship. Based on the carbohydrate abundances in both the PCHO and DCHO pools, we conclude that this material mainly derives from allochthonous sources (vascular plants, bacteria and soils). Moreover, during flood events, an enrichment in mannose in POM was observed, probably reflecting an angiosperm source (leaves or grasses). By expanding our results to the northwestern Mediterranean Sea (Gulf of Lions), we found that the total organic carbon (TOC) fluxes of the Rhône River accounted for ~1 % of the standing stock of seawater TOC. Considering that glucose is the most abundant carbohydrate in both particulate and dissolved organic matter pools (~33 %), its annual

  15. Effect of Thermal Cycling on Creep Behavior of Powder-Metallurgy-Processed and Hot-Rolled Al and Al-SiC Particulate Composites

    NASA Astrophysics Data System (ADS)

    Pal, Sharmilee; Bhanuprasad, V. V.; Mitra, R.; Ray, K. K.

    2009-12-01

    The tensile creep behavior of powder metallurgy (P/M)-processed and hot-rolled commercially pure Al and Al-5 or Al-10 vol pct SiC particulate composites has been evaluated after subjecting to 0, 2, and 8 thermal cycles between 500 °C and 0 °C with rapid quenching. The images of microstructures obtained using scanning and transmission electron microscopy as well as changes in the electrical resistivity, Young’s modulus, and microhardness have been examined in the samples subjected to thermal cycling, in order to compare the effects of structural damage and strengthening by dislocation generation. The damage is caused by voids formed by vacancy coalescence, and is more severe in pure Al than in Al-SiCp composites, because the particle-matrix interfaces in the composites act as effective sinks for vacancies. Creep tests have shown that the application of 2 thermal cycles lowers the creep strain rates in both pure Al and Al-SiCp composites. However, the creep resistance of pure Al gets significantly deteriorated, unlike the mild deterioration in the Al-5 SiCp composite, while the time to rupture for the Al-10 SiCp composite is increased. The dislocation structure and subgrain sizes in the Al and in the matrices of the Al-SiCp composites in the as-rolled condition, after thermal cycling, and after creep tests, have been compared and related to the creep behavior. The dimple sizes of the crept fracture surfaces appear to be dependent on the void density, tertiary component of strain, and time to rupture.

  16. A model cerium oxide matrix composite reinforced with a homogeneous dispersion of silver particulate - prepared using the glycine-nitrate process

    SciTech Connect

    Weil, K. Scott; Hardy, John S.

    2005-01-31

    Recently a new method of ceramic brazing has been developed. Based on a two-phase liquid composed of silver and copper oxide, brazing is conducted directly in air without the need of an inert cover gas or the use of surface reactive fluxes. Because the braze displays excellent wetting characteristics on a number ceramic surfaces, including alumina, various perovskites, zirconia, and ceria, we were interested in investigating whether a metal-reinforced ceramic matrix composite (CMC) could be developed with this material. In the present study, two sets of homogeneously mixed silver/copper oxide/ceria powders were synthesized using a combustion synthesis technique. The powders were compacted and heat treated in air above the liquidus temperature for the chosen Ag-CuO composition. Metallographic analysis indicates that the resulting composite microstructures are extremely uniform with respect to both the size of the metallic reinforcement as well as its spatial distribution within the ceramic matrix. The size, morphology, and spacing of the metal particulate in the densified composite appears to be dependent on the original size and the structure of the starting combustion synthesized powders.

  17. An investigation on the rheological behavior of metallic semi-solid slurries of Al-6.5 pct Si and semi-solid composite slurries of SiC particulates in an Al-6.5 pct Si alloy matrix

    NASA Technical Reports Server (NTRS)

    Moon, H.-K.; Ito, Y.; Cornie, J. A.; Flemings, M. C.

    1993-01-01

    The rheology of SiC particulate/Al-6.5 pct Si composite slurries was explored. The rheological behavior of the composite slurries shows both thixotropic and pseudoplastic behaviors. Isostructural experiments on the composite slurries revealed a Newtonian behavior beyond a high shear rate limit. The rheology of fully molten composite slurries over the low to high shear rate range indicates the existence of a low shear rate Newtonian region, an intermediate pseudoplastic region and a high shear rate Newtonian region. The isostructural studies indicate that the viscosity of a composite slurry depends upon the shearing history of a given volume of material. An unexpected shear thinning was noted for SiC particulate + alpha slurries as compared to semi-solid metallic slurries at the same fraction solid. The implications of these findings for the processing of slurries into cast components is discussed.

  18. Seasonal survey of the composition and degradation state of particulate organic matter in the Rhone River using lipid tracers

    NASA Astrophysics Data System (ADS)

    Galeron, M.-A.; Amiraux, R.; Charriere, B.; Radakovitch, O.; Raimbault, P.; Garcia, N.; Lagadec, V.; Vaultier, F.; Rontani, J.-F.

    2014-10-01

    Lipid tracers including fatty acids, hydroxyacids, n-alkanols, sterols and triterpenoids were used to determine the origin and fate of suspended particulate organic matter (POM) collected in the Rhone River (France). This seasonal survey (April 2011 to May 2013) revealed a year-round strong terrigenous contribution to the plant-derived particulate organic matter (POM), with significant algal inputs observed in March and attributed to phytoplanktonic blooms likely dominated by diatoms. Major terrigenous contributors to our samples are gymnosperms, and more precisely their roots and stems, as evidenced by the presence of high proportions of ω-hydroxydocosanoic acid (a suberin biomarker). The high amounts of coprostanol detected clearly show that the Rhone River is significantly affected by sewage waters. Specific sterol degradation products were quantified and used to assess the part of biotic and abiotic degradation of POM within the river. Plant-derived organic matter appears to be mainly affected by photo-oxidation and autoxidation (free radical oxidation), while organic matter of human origin, evidenced by the presence of coprostanol, is clearly more prone to bacterial degradation. Despite the involvement of an intense autoxidation-inducing homolytic cleavage of peroxy bonds, a significant proportion of hydroperoxides is still intact in higher plant debris. These compounds could affect the degradation of terrestrial material by inducing an intense autoxidation upon its arrival at sea.

  19. Modeling of the chemical composition of fine particulate matter: Development and performance assessment of EASYWRF-Chem

    NASA Astrophysics Data System (ADS)

    Mendez, M.; Lebègue, P.; Visez, N.; Fèvre-Nollet, V.; Crenn, V.; Riffault, V.; Petitprez, D.

    2016-03-01

    The European emission Adaptation SYstem for the WRF-Chem model (EASYWRF-Chem) has been developed to generate chemical information supporting the WRF-Chem requirements from any emission inventory based on the CORINAIR methodology. Using RADM2 and RACM2 mechanisms, "emission species" are converted into "model species" thanks to the SAPRC methodology for gas phase pollutant and the PM10 and PM2.5 fractions. Furthermore, by adapting US EPA PM2.5 profiles, the processing of aerosol chemical speciation profiles separates the unspeciated PM2.5 emission into five chemical families: sulfates, nitrates, elemental carbon, organic aerosol and unspeciated aerosol. The evaluation of the model has been performed by separately comparing model outcomes with (i) meteorological measurements; (ii) NO2, O3, PM10 and PM2.5 mass concentrations from the regional air quality monitoring network; (iii) hourly-resolved data from four field campaign measurements, in winter and in summer, on two sites in the French northern region. In the latter, a High Resolution - Time of Flight - Aerosol Mass Spectrometer (HR-ToF-AMS) provided non-refractory PM1 concentrations of sulfate, nitrate and ammonium ions as well as organic matter (OM), while an aethalometer provided black carbon (BC) concentrations in the PM2.5 fraction. Meteorological data (temperature, wind, relative humidity) are well simulated for all the time series data except for specific events as wind direction changes or rainfall. For particulate matter, results are presented by considering firstly the total mass concentration of PM2.5 and PM10. EASYWRF-Chem simulations overestimated the PM10 mass concentrations by + 22% and + 4% for summer and winter periods respectively, whereas for the finer PM2.5 fraction, mass concentrations were overestimated by + 20% in summer and underestimated by - 13% in winter. Simulated sulfate concentrations were underestimated and nitrate concentrations were overestimated but hourly variations were well

  20. Mechanical properties of particulate composites based on a body-centered-cubic Mg-Li alloy containing boron

    NASA Technical Reports Server (NTRS)

    Whalen, R. T.; Gonzalez-Doncel, G.; Robinson, S. L.; Sherby, O. D.

    1989-01-01

    The effect of substituting the Mg metal in Mg-B composites by a Mg-14 wt pct Li solid solution on the ductility of the resulting composite was investigated using elastic modulus measurements on the P/M composite material prepared with a dispersion of B particles (in a vol pct range of 0-30) in a matrix of Mg-14 wt pct Li-1.5 wt pct Al. It was found that the elastic modulus of the composites increased rapidly with increasing boron, with specific stiffness values reaching about two times that of most structural materials. The values of the compression and tensile strengths increased significantly with boron additions. Good tensile ductility was achieved at the level of 10 vol pct B. However, at 20 vol pct B, the Mg-Li composite exhibited only limited tensile ductility (about 2 percent total elongation).

  1. A chlorhexidine-releasing epoxy-based coating on titanium implants prevents Staphylococcus aureus experimental biomaterial-associated infection.

    PubMed

    Riool, M; Dirks, A J; Jaspers, V; de Boer, L; Loontjens, T J; van der Loos, C M; Florquin, S; Apachitei, I; Rijk, L N; Keul, H A; Zaat, S A

    2017-02-14

    Prevention of biomaterial-associated infections (BAI) remains a challenging problem, in particular due to the increased risk of resistance development with the current antibiotic-based strategies. Metallic orthopaedic devices, such as non-cemented implants, are often inserted under high mechanical stress. These non-cemented implants cannot be protected by e.g. antibioticreleasing bone cement or other antimicrobial approaches, such as the use of bioactive glass. Therefore, in order to avoid abrasion during implantation procedures, we developed an antimicrobial coating with great mechanical stability for orthopaedic implants, to prevent Staphylococcus aureus BAI. We incorporated 5 and 10 wt % chlorhexidine in a novel mechanically stable epoxy-based coating, designated CHX5 and CHX10, respectively. The coatings displayed potent bactericidal activity in vitro against S. aureus, with over 80 % of the release (19 µg/cm2 for CHX5 and 41 µg/cm2 for CHX10) occurring within the first 24 h. In mice, the CHX10 coating significantly reduced the number of CFU (colony forming units), both on the implants and in the peri-implant tissues, 1 d after S. aureus challenge. The CHX10-coated implants were well-tolerated by the animals, with no signs of toxicity observed by histological analysis. Moreover, the coating significantly reduced the frequency of culture-positive tissues 1 d, and of culture-positive implants 1 and 4 d after challenge. In summary, the chlorhexidine-releasing mechanically stable epoxy-based CHX10 coating prevented implant colonisation and S. aureus BAI in mice and has good prospects for clinical development.

  2. Effects of filter loading and filter type on the mutagenicity and composition of diesel exhaust particulate extracts

    NASA Astrophysics Data System (ADS)

    Gorse, R. A.; Salmeen, I. T.; Clark, C. R.

    Diesel vehicle exhaust particles were simultaneously collected from a dilution tube on three commonly used types of filters. Sampling was performed over single cycles and over 7 or 10cycles of the 1974 Hot-start Federal Test Procedure (FTP/H). Particulate loadings on the filters ranged from 48 to 660 μg cm -2. The filters were extracted with dichloromethane and the extracts were characterized by the Ames Salmonella-histidine reversion assay (strains TA98 and TA 100, without microsomal activation) and by high performance liquid chromatography (HPLC) with fluorescence detection. It was found that the extracts from lightly loaded filters of the three types were indistinguishable. A similar conclusion obtains for the heavily loaded filters, confirming our results from an earlier study (Clark C. R., Truex T. J., Lee K. S. C. and Salmeen I. T. et al., 1981 Atmospheric Environment15, 397-402). The percentage of extractable material in the paniculate matter, the fluorescent intensities of two of the four HPLC fractions and the Ames assay activities (revertants per μg of extract) each increase linearly with paniculate loading on the filters. We attribute these increases to reactions between the particle-bound organic material and reactive gases in the exhaust stream.

  3. Zinc isotopic composition of particulate matter generated during the combustion of coal and coal + tire-derived fuels.

    PubMed

    Borrok, David M; Gieré, Reto; Ren, Minghua; Landa, Edward R

    2010-12-01

    Atmospheric Zn emissions from the burning of coal and tire-derived fuel (TDF) for power generation can be considerable. In an effort to lay the foundation for tracking these contributions, we evaluated the Zn isotopes of coal, a mixture of 95 wt % coal + 5 wt % TDF, and the particulate matter (PM) derived from their combustion in a power-generating plant. The average Zn concentrations and δ(66)Zn were 36 mg/kg and 183 mg/kg and +0.24‰ and +0.13‰ for the coal and coal + TDF, respectively. The δ(66)Zn of the PM sequestered in the cyclone-type mechanical separator was the lightest measured, -0.48‰ for coal and -0.81‰ for coal+TDF. The δ(66)Zn of the PM from the electrostatic precipitator showed a slight enrichment in the heavier Zn isotopes relative to the starting material. PM collected from the stack had the heaviest δ(66)Zn in the system, +0.63‰ and +0.50‰ for the coal and coal + TDF, respectively. Initial fractionation during the generation of a Zn-rich vapor is followed by temperature-dependent fractionation as Zn condenses onto the PM. The isotopic changes of the two fuel types are similar, suggesting that their inherent chemical differences have only a secondary impact on the isotopic fractionation process.

  4. Zinc isotopic composition of particulate matter generated during the combustion of coal and coal + tire-derived fuels

    USGS Publications Warehouse

    Borrok, D.M.; Gieré, R.; Ren, M.; Landa, E.R.

    2010-01-01

    Atmospheric Zn emissions from the burning of coal and tire-derived fuel (TDF) for power generation can be considerable. In an effort to lay the foundation for tracking these contributions, we evaluated the Zn isotopes of coal, a mixture of 95 wt % coal + 5 wt % TDF, and the particulate matter (PM) derived from their combustion in a power-generating plant. The average Zn concentrations and δ(66)Zn were 36 mg/kg and 183 mg/kg and +0.24‰ and +0.13‰ for the coal and coal + TDF, respectively. The δ(66)Zn of the PM sequestered in the cyclone-type mechanical separator was the lightest measured, -0.48‰ for coal and -0.81‰ for coal+TDF. The δ(66)Zn of the PM from the electrostatic precipitator showed a slight enrichment in the heavier Zn isotopes relative to the starting material. PM collected from the stack had the heaviest δ(66)Zn in the system, +0.63‰ and +0.50‰ for the coal and coal + TDF, respectively. Initial fractionation during the generation of a Zn-rich vapor is followed by temperature-dependent fractionation as Zn condenses onto the PM. The isotopic changes of the two fuel types are similar, suggesting that their inherent chemical differences have only a secondary impact on the isotopic fractionation process.

  5. Quantification of the sources and composition of particulate matter by field-deployable mass spectrometry: implications for air quality and public health.

    PubMed

    Hayes, Patrick L

    2017-02-27

    Airborne particulate matter less than 2.5 μm in diameter (PM2.5) negatively impacts air quality in cities throughout the world where it has been linked to increased cardiac and respiratory morbidity and mortality. For this reason PM2.5 standards have been established by many countries and the World Health Organization. However, these guidelines are regularly exceeded in North America, Europe and East Asia. While PM2.5 is often reported as a single atmospheric species, it is actually a mixture of organic and inorganic compounds. The organic fraction, termed organic aerosol (OA), contributes approximately 20-70% of the PM2.5 mass globally, and OA itself is a complex mixture of thousands of compounds. Characterizing the chemical properties of OA represents a major analytical challenge that has motivated the development of a range of new instruments. The focus of this perspective is the use of field-deployable mass spectrometers and in particular the Aerodyne Aerosol Mass Spectrometer (AMS) for chemically characterizing submicron particles. Field measurements of the composition of PM2.5 are directly relevant to evaluating its health impact because reductions in life expectancy due to PM2.5 vary according to composition. In addition, AMS measurements are especially useful for characterizing OA. The sources of OA are not well understood as evidenced by the performance of many air quality models, including those run by government agencies, which lack accurate and well constrained parameterizations for simulating secondary OA concentrations in urban regions. Given that OA is an important component of the total PM2.5 mass, this uncertainty makes accurate evaluation of the impact of PM2.5 on public health difficult, especially when evaluating future mitigation strategies. The development of the AMS has been a critical step towards addressing this public health challenge in that it provides quantitative data regarding particulate matter and OA concentration and composition

  6. Dynamic magnetoelastic properties of epoxy-bonded Sm0.88Nd0.12Fe1.93 pseudo-1-3 negative magnetostrictive particulate composite

    NASA Astrophysics Data System (ADS)

    Yang, Fang; Leung, Chung Ming; Or, Siu Wing; Liu, Wei; Zhang, Zhidong; Duan, Yuan-Feng

    2012-04-01

    Pseudo-1-3 negative magnetostrictive particulate composite is prepared by embedding and aligning light rare earth (Sm and Nd)-based negative magnetostrictive Sm0.88Nd0.12Fe1.93 particles with randomly distributed sizes of 10-180 μm in a passive epoxy matrix using a particle volume fraction of 0.5. The dynamic magnetoelastic properties of the composite are investigated as a function of both magnetic bias field and frequency under a constant magnetic drive field. The dynamic relative permeability (μr33) exhibits a flat frequency response with no observable dispersion at all bias field levels, except for the fundamental shape resonance range of 40-50 kHz. The free (μr33T) and clamped (μr33S) relative permeabilities attain their maximum values at low bias field levels of ≤10 kA/m because of the relatively easy 180° domain-wall motion. The elastic modulus at constant magnetic field strength (E3H) and that at constant magnetic flux density (E3B) show a maximum negative-ΔE effect, accompanying a maximum dynamic strain coefficient (d33) of -2 nm/A, at about 100 kA/m due to the maximum motion of non-180° domain walls.

  7. Exploration of the composition and sources of urban fine particulate matter associated with same-day cardiovascular health effects in Dearborn, Michigan

    PubMed Central

    Morishita, Masako; Bard, Robert L.; Kaciroti, Niko; Fitzner, Craig A.; Dvonch, Timothy; Harkema, Jack R.; Rajagopalan, Sanjay; Brook, Robert D.

    2015-01-01

    The objective was to explore associations of chemical components and source factors of ambient fine particulate matter (aerodynamic diameter ≤2.5 μm; PM2.5) with cardiovascular (CV) changes following same-day exposure to ambient PM2.5. Twenty-five healthy adults living in rural Michigan were exposed to ambient air in an urban/industrial community for 4 to 5 h daily for five consecutive days. CV health outcomes were measured 1–2 h post exposure. Contributing emission sources were identified via positive matrix factorization. We examined associations between PM2.5 mass, composition and source factors, and same-day changes in CV outcomes using mixed-model analyses. PM2.5 mass (10.8±6.8 μg/m3), even at low ambient levels, was significantly associated with increased heart rate (HR). Trace elements as well as secondary aerosol, diesel/urban dust and iron/steel manufacturing factors potentially explained the HR changes. However, trace element analysis demonstrated additional associations with other CV responses including changes in blood pressure (BP), arterial compliance, autonomic balance and trends toward reductions in endothelial function. Two factors were related to BP changes (diesel/urban dust, motor vehicle) and trends toward impaired endothelial function (diesel/urban dust). This study indicates composition of PM2.5 and its sources may contribute to CV health effects independently of PM2.5 mass. PMID:24866265

  8. Magnetic characterization of airborne particulates

    NASA Astrophysics Data System (ADS)

    Kim, W.; Doh, S.; Yu, Y.

    2010-12-01

    Burning fossil fuels from vehicles, domestics, industries and power plants in the large urban or industrial areas emit significant quantity of anthropogenic particulates which become a potential threat to human health. Here, we present temporal variability of particulate pollution associated with compositional differences, using magnetic measurements and electron microscopic observations. Six different grain-sizes of airborne particulates have been collected by filtering from 10 precipitation events in Seoul, Korea from February 2009 to June 2009. Magnetic concentration proxies show relatively better (R2 >0.6) and poorer correlations (R2 <0.3) with the masses of samples filtered by >0.45 μm and <0.45 μm sizes, respectively, suggesting the usefulness of magnetic characterization for the >0.45 μm particulates. Temporally, magnetic concentrations are higher in the cold season than the warm season. In particular, a significant increase of magnetic concentration is observed in 3 μm and 1 μm filters after the Chinese wind-blown dust events, indicating additional influx of fine-grained anthropogenic particulates into Seoul. Microscopic observations identify that increase of magnetic concentration is highly linked with the frequent occurrence of combustion derived particulates (i.e., carbon and/or sulfur mixed particles) than natural alumino-silicates. Overall, the present study demonstrates that magnetic measurements efficiently reflect the concentration of particulates produced from fossil-fuel combustion among the airborne particles from various sources.

  9. Composition, toxicity, and mutagenicity of particulate and semivolatile emissions from heavy-duty compressed natural gas-powered vehicles.

    PubMed

    Seagrave, JeanClare; Gigliotti, Andrew; McDonald, Jacob D; Seilkop, Steven K; Whitney, Kevin A; Zielinska, Barbara; Mauderly, Joe L

    2005-09-01

    Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by compressed natural gas. The bus engines included a well-functioning, conventional engine; a "high emitter" engine; and a new technology engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of engine oil constituents. PM + SVOC samples were also collected for mutagenicity and toxicity testing. Extraction efficiencies from the collection media were lower than for similarly collected samples from gasoline or diesel vehicles. Responses to the recovered samples were compared on the basis of exhaust volume, to incorporate the emission rates into the potency factors. Mutagenicity was assessed by Salmonella reverse mutation assay. Mutagenicity was greatest for the high emitter sample and lowest for the new technology sample. Metabolic activation reduced mutagenicity in strain TA100, but not TA98. Toxicity, including inflammation, cytotoxicity, and parenchymal changes, was assessed 24 h after intratracheal instillation into rat lungs. Lung responses were generally mild, with little difference between the responses to equivalent volumes of emissions from the normal emitter and the new technology, but greater responses for the high emitter. These emission sample potencies are further compared on the basis of recovered mass with previously reported samples from normal and high-emitter gasoline and diesel vehicles. While mutagenic potencies for the CNG emission samples were similar to the range observed in the gasoline and diesel emission samples, lung toxicity potency factors were generally lower than those for the gasoline and diesel samples.

  10. Spatial and Temporal Variation in Fine Particulate Matter Mass and Chemical Composition: The Middle East Consortium for Aerosol Research Study

    PubMed Central

    Abdeen, Ziad; Heo, Jongbae; Wu, Bo; Shpund, Jacob; Vanger, Arye; Sharf, Geula; Moise, Tamar; Brenner, Shmuel; Nassar, Khaled; Saleh, Rami; Al-Mahasneh, Qusai M.; Sarnat, Jeremy A.; Schauer, James J.

    2014-01-01

    Ambient fine particulate matter (PM2.5) samples were collected from January to December 2007 to investigate the sources and chemical speciation in Palestine, Jordan, and Israel. The 24-h PM2.5 samples were collected on 6-day intervals at eleven urban and rural sites simultaneously. Major chemical components including metals, ions, and organic and elemental carbon were analyzed. The mass concentrations of PM2.5 across the 11 sites varied from 20.6 to 40.3 μg/m3, with an average of 28.7 μg/m3. Seasonal variation of PM2.5 concentrations was substantial, with higher average concentrations (37.3 μg/m3) in the summer (April–June) months compared to winter (October–December) months (26.0 μg/m3) due mainly to high contributions of sulfate and crustal components. PM2.5 concentrations in the spring were greatly impacted by regional dust storms. Carbonaceous mass was the most abundant component, contributing 40% to the total PM2.5 mass averaged across the eleven sites. Crustal components averaged 19.1% of the PM2.5 mass and sulfate, ammonium, and nitrate accounted for 16.2%, 6.4%, and 3.7%, respectively, of the total PM2.5 mass. The results of this study demonstrate the need to better protect the health and welfare of the residents on both sides of the Jordan River in the Middle East. PMID:25045751

  11. Composition and major sources of organic compounds of aerosol particulate matter sampled during the ACE-Asia campaign

    NASA Astrophysics Data System (ADS)

    Simoneit, Bernd R. T.; Kobayashi, Minoru; Mochida, Michihiro; Kawamura, Kimitaka; Lee, Meehye; Lim, Ho-Jin; Turpin, Barbara J.; Komazaki, Yuichi

    2004-10-01

    The organic compound tracers of atmospheric particulate matter, as well as organic carbon (OC) and elemental carbon (EC), have been characterized for samples acquired during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) from Gosan, Jeju Island, Korea, from Sapporo, Japan, and from Chichi-jima Island in the western North Pacific, as well as on the National Oceanic and Atmospheric Administration R/V Ronald H. Brown. Total extracts were analyzed by gas chromatography-mass spectrometry to determine both polar and aliphatic compounds. Total particles, organic matter, and lipid and saccharide compounds were high during the Asian dust episode (early April 2001) compared to levels at other times. The organic matter can be apportioned to seven emission sources and to significant oxidation-producing secondary products during long-range transport. Terrestrial natural background compounds are vascular plant wax lipids derived from direct emission and as part of desert sand dust. Fossil fuel utilization is obvious and derives from petroleum product and coal combustion emissions. Saccharides are a major polar (water-soluble) carbonaceous fraction derived from soil resuspension (agricultural activities). Biomass-burning smoke is evident in all samples and seasons. It contributes up to 13% of the total compound mass as water-soluble constituents. Burning of refuse is another source of organic particles. Varying levels of marine-derived lipids are superimposed during aerosol transport over the ocean. Secondary oxidation products increase with increasing transport distance and time. The ACE-Asia aerosols are composed not only of desert dust but also of soil dust, smoke from biomass and refuse burning, and emissions from fossil fuel use in urban areas.

  12. New Insights from Zinc and Copper Isotopic Compositions into the Sources of Atmospheric Particulate Matter from Two Major European Cities.

    PubMed

    Gonzalez, R Ochoa; Strekopytov, S; Amato, F; Querol, X; Reche, C; Weiss, D

    2016-09-20

    This study reports spatial and temporal variability of Zn and Cu isotopes in atmospheric particulate matter (PM) collected in two major European cities with contrasting atmospheric pollution, Barcelona and London. We demonstrate that nontraditional stable isotopes identify source contributions of Zn and Cu and can play a major role in future air quality studies. In Barcelona, samples of fine PM were collected at street level at sites with variable traffic density. The isotopic signatures ranged between -0.13 ± 0.09 and -0.51 ± 0.05‰ for δ(66)ZnIRMM and between +0.04 ± 0.20 and +0.33 ± 0.15‰ for δ(65)CuAE633. Copper isotope signatures similar to those of Cu sulfides and Cu/Sb ratios within the range typically found in brake wear suggest that nonexhaust emissions from vehicles are dominant. Negative Zn isotopic signatures characteristic for gaseous emissions from smelting and combustion and large enrichments of Zn and Cd suggest contribution from metallurgical industries. In London, samples of coarse PM collected on the top of a building over 18 months display isotope signatures ranging between +0.03 ± 0.04 and +0.49 ± 0.02‰ for δ(66)ZnIRMM and between +0.37 ± 0.17 and +0.97 ± 0.21‰ for δ(65)CuAE633. Heavy Cu isotope signatures (up to +0.97 ± 0.21‰) and higher enrichments and Cu/Sb ratios during winter time indicate important contribution from fossil fuel combustion. The positive δ(66)ZnIRMM signatures are in good agreement with signatures characteristic for ore concentrates used for the production of tires and galvanized materials, suggesting nonexhaust emissions from vehicles as the main source of Zn pollution.

  13. Spatial and temporal variation in fine particulate matter mass and chemical composition: the Middle East Consortium for Aerosol Research Study.

    PubMed

    Abdeen, Ziad; Qasrawi, Radwan; Heo, Jongbae; Wu, Bo; Shpund, Jacob; Vanger, Arye; Sharf, Geula; Moise, Tamar; Brenner, Shmuel; Nassar, Khaled; Saleh, Rami; Al-Mahasneh, Qusai M; Sarnat, Jeremy A; Schauer, James J

    2014-01-01

    Ambient fine particulate matter (PM2.5) samples were collected from January to December 2007 to investigate the sources and chemical speciation in Palestine, Jordan, and Israel. The 24-h PM2.5 samples were collected on 6-day intervals at eleven urban and rural sites simultaneously. Major chemical components including metals, ions, and organic and elemental carbon were analyzed. The mass concentrations of PM2.5 across the 11 sites varied from 20.6 to 40.3 μg/m(3), with an average of 28.7 μg/m(3). Seasonal variation of PM2.5 concentrations was substantial, with higher average concentrations (37.3 μg/m(3)) in the summer (April-June) months compared to winter (October-December) months (26.0 μg/m(3)) due mainly to high contributions of sulfate and crustal components. PM2.5 concentrations in the spring were greatly impacted by regional dust storms. Carbonaceous mass was the most abundant component, contributing 40% to the total PM2.5 mass averaged across the eleven sites. Crustal components averaged 19.1% of the PM2.5 mass and sulfate, ammonium, and nitrate accounted for 16.2%, 6.4%, and 3.7%, respectively, of the total PM2.5 mass. The results of this study demonstrate the need to better protect the health and welfare of the residents on both sides of the Jordan River in the Middle East.

  14. Rheological Behavior and Microstructure of Ceramic Particulate/Aluminum Alloy Composites. Ph.D. Thesis Final Technical Report

    NASA Technical Reports Server (NTRS)

    Moon, Hee-Kyung

    1990-01-01

    The rheological behavior and microstructure were investigated using a concentric cylinder viscometer for three different slurries: semi-solid alloy slurries of a matrix alloy, Al-6.5wt percent Si: composite slurries, SiC (sub p) (8.5 microns)/Al-6.5wt percent Si, with the same matrix alloy in the molten state, and composite slurries of the same composition with the matrix alloy in the semi-solid state. The pseudoplasticity of these slurries was obtained by step changes of the shear rate from a given initial shear rate. To study the thixotropic behavior of the system, a slurry was allowed to rest for different periods of time, prior to shearing at a given initial shear rate. In the continuous cooling experiments, the viscosities of these slurries were dependent on the shear rate, cooling rate, volume fraction of the primary solid of the matrix alloy, and volume fraction of silicon carbide. In the isothermal experiments, all three kinds of slurries exhibited non-Newtonian behavior, depending on the volume fraction of solid particles.

  15. The effects of electron and gamma radiation on epoxy-based materials

    NASA Technical Reports Server (NTRS)

    Fornes, R. E.; Memory, J. D.; Gilbert, R. D.; Long, E. R., Jr.

    1982-01-01

    Specimens of graphite/epoxy composites and epoxy resins were exposed to electron and gamma radiation, followed by mechanical property and fundamental measurements. Measurement techniques included: scanning electron microscopy, X-ray diffraction analysis, and electron spin resonance spectroscopic analysis. Results indicate little or no change in flexural properties of miniature specimens of a graphite/epoxy composite and no change in failure mode at the fiber-resin interface and in the crystallinity of the fiber and the resin. Some doubt in the observation of stable flexural properties is cast by electron paramagnetic resonance spectra of a relatively large number of radiation-generated radicals. These generally lead to a change in cross-linking and in chain-scissioning which should alter mechanical properties.

  16. Particulate matter in California: part 2--Spatial, temporal, and compositional patterns of PM2.5, PM10-2.5, and PM10.

    PubMed

    Motallebi, Nehzat; Taylor, Clinton A; Croes, Bart E

    2003-12-01

    Geographic and temporal variations in the concentration and composition of particulate matter (PM) provide important insights into particle sources, atmospheric processes that influence particle formation, and PM management strategies. In the nonurban areas of California, annual-average PM2.5 and PM10 concentrations range from 3 to 10 microg/m3 and from 5 to 18 microg/m3, respectively. In the urban areas of California, annual-averages for PM2.5 range from 7 to 30 microg/m3, with observed 24-hr peaks reaching levels as high as 160 microg/m3. Within each air basin, exceedances are a mixture of isolated events as well as periods of elevated PM2.5 concentrations that are more prolonged and regional in nature. PM2.5 concentrations are generally highest during the winter months. The exception is the South Coast Air Basin, where fairly high values occur throughout the year. Annual-average PM2.5 mass, as well as the concentrations of major components, declined from 1988 to 2000. The declines are especially pronounced for the sulfate (SO4(2-)) and nitrate (NO3-) components of PM2.5 and PM10) and correlate with reductions in ambient levels of oxides of sulfur (SOx) and oxides of nitrogen (NOx). Annual averages for PM10-2.5 and PM10 exhibited similar downwind trends from 1994 to 1999, with a slightly less pronounced decrease in the coarse fraction.

  17. Dose-dependent intracellular reactive oxygen and nitrogen species (ROS/RNS) production from particulate matter exposure: comparison to oxidative potential and chemical composition

    NASA Astrophysics Data System (ADS)

    Tuet, Wing Y.; Fok, Shierly; Verma, Vishal; Tagle Rodriguez, Marlen S.; Grosberg, Anna; Champion, Julie A.; Ng, Nga L.

    2016-11-01

    Elevated particulate matter (PM) concentrations have been associated with cardiopulmonary risks. In this study, alveolar macrophages and ventricular myocytes were exposed to PM extracts from 104 ambient filters collected in multiple rural and urban sites in the greater Atlanta area. PM-induced reactive oxygen/nitrogen species (ROS/RNS) were measured to investigate the effect of chemical composition and determine whether chemical assays are representative of cellular responses. For summer samples, the area under the ROS/RNS dose-response curve per volume of air (AUCvolume) was significantly correlated with dithiothreitol (DTT) activity, water-soluble organic carbon (WSOC), brown carbon, titanium, and iron, while a relatively flat response was observed for winter samples. EC50 was also correlated with max response for all filters investigated, which suggests that certain PM constituents may be involved in cellular protective pathways. Although few metal correlations were observed, exposure to laboratory-prepared metal solutions induced ROS/RNS production, indicating that a lack of correlation does not necessarily translate to a lack of response. Collectively, these results suggest that complex interactions may occur between PM species. Furthermore, the strong correlation between organic species and ROS/RNS response highlights a need to understand the contribution of organic aerosols, especially photochemically driven secondary organic aerosols (SOA), to PM-induced health effects.

  18. Composition-explicit distillation curves of diesel fuel with glycol ether and glycol ester oxygenates: fuel analysis metrology to enable decreased particulate emissions.

    PubMed

    Smith, Beverly L; Ott, Lisa S; Bruno, Thomas J

    2008-10-15

    We recently introduced several important improvements in the measurement of distillation curves of complex fluids. The modifications to the classical measurement provide for (1) a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state, (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development, (4) consistency with a century of historical data, (5) an assessment of the energy content of each distillate fraction, (6) trace chemical analysis of each distillate fraction, and (7) corrosivity assessment of each distillate fraction. We have applied the new method to the measurement of rocket propellant, gasolines, jet fuels, and hydrocarbon crude oils. In this paper we presentthe application of the technique to representative diesel fuel and mixtures of diesel fuel with some of the more promising oxygenating agents; namely, the glycol ethers and glycol esters: tri(propylene glycol) methyl ether (TPM), dibutyl maleate (DBM), and an 80/ 20 (vol/vol) mixture of diethylene glycol methyl ether (DGME) + 1,2-dimethoxyethane (DME) a mixture often referred to as Cetaner. We present not only the distillation curves but also a chemical characterization of each fraction, and discuss the contrasts between the various mixtures. The measurements are significant as an environmental design tool for decreased particulate emissions.

  19. Airborne Particulate Threat Assessment

    SciTech Connect

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  20. Study of the chemical composition of particulate matter from the Rio de Janeiro metropolitan region, Brazil, by inductively coupled plasma-mass spectrometry and optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Mateus, Vinícius Lionel; Monteiro, Isabela Luizi Gonçalves; Rocha, Rafael Christian Chávez; Saint'Pierre, Tatiana Dillenburg; Gioda, Adriana

    2013-08-01

    Air quality in the metropolitan region of Rio de Janeiro was evaluated by analysis of particulate matter (PM) in industrial (Santa Cruz) and rural (Seropédica) areas. Total suspended particles (TSP) and fine particulate matter (PM2.5) collected in filters over 24 h were quantified and their chemical composition determined. TSP exceeded Brazilian guidelines (80 μg m- 3) in Santa Cruz, while PM2.5 levels exceeded the World Health Organization guidelines (10 μg m- 3) in both locations. Filters were extracted with water and/or HNO3, and the concentrations of 20 elements, mostly metals, were determined by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP OES). Water soluble inorganic anions were determined by ion chromatography (IC). To estimate the proportion of these elements extracted, a certified reference material (NIST SRM 1648a, Urban Dust) was subjected to the same extraction process. Concordant results were obtained by ICP-MS and ICP OES for most elements. Some elements could not be quantified by both techniques; the most appropriate technique was chosen in each case. The urban dust was also analyzed by the United States Environmental Protection Agency (US EPA) method, which employs a combination of hydrochloric and nitric acids for the extraction, but higher extraction efficiency was obtained when only nitric acid was employed. The US EPA method gave better results only for Sb. In the PM samples, the elements found in the highest average concentrations by ICP were Zn and Al (3-6 μg m- 3). The anions found in the highest average concentrations were SO42 - in PM2.5 (2-4 μg m- 3) and Cl- in TSP (2-6 μg m- 3). Principal component analysis (PCA) in combination with enrichment factors (EF) indicated industrial sources in PM2.5. Analysis of TSP suggested both anthropogenic and natural sources. In conclusion, this work contributes data on air quality, as well as a method for the analysis of PM samples by ICP-MS.

  1. Integration of microchip electrophoresis with electrochemical detection using an epoxy-based molding method to embed multiple electrode materials.

    PubMed

    Johnson, Alicia S; Selimovic, Asmira; Martin, R Scott

    2011-11-01

    This paper describes the use of epoxy-encapsulated electrodes to integrate microchip-based electrophoresis with electrochemical detection. Devices with various electrode combinations can easily be developed. This includes a palladium decoupler with a downstream working electrode material of either gold, mercury/gold, platinum, glassy carbon, or a carbon fiber bundle. Additional device components such as the platinum wires for the electrophoresis separation and the counter electrode for detection can also be integrated into the epoxy base. The effect of the decoupler configuration was studied in terms of the separation performance, detector noise, and the ability to analyze samples of a high ionic strength. The ability of both glassy carbon and carbon fiber bundle electrodes to analyze a complex mixture was demonstrated. It was also shown that a PDMS-based valving microchip can be used along with the epoxy-embedded electrodes to integrate microdialysis sampling with microchip electrophoresis and electrochemical detection, with the microdialysis tubing also being embedded in the epoxy substrate. This approach enables one to vary the detection electrode material as desired in a manner where the electrodes can be polished and modified as is done with electrochemical flow cells used in liquid chromatography.

  2. Temporal variability of atmospheric particulate matter and chemical composition during a growing season at an agricultural site in northeastern China.

    PubMed

    Chen, Weiwei; Tong, Daniel; Zhang, Shichun; Dan, Mo; Zhang, Xuelei; Zhao, Hongmei

    2015-12-01

    This study presents the observations of PM10 and PM2.5 concentrations at an agricultural site from April to October 2012 in Dehui city, China. Ambient air was sampled by filter-based samplers and online PM monitors. The filter samples were analyzed to determine the abundance of ionic/inorganic elements, organic carbon (OC) and elemental carbon (EC). The daily PM10 concentrations varied significantly over the monitoring period, with an average of 168±63 (in the range of 52-277)μg/m(3) during the land preparation/planting period (26 April-15 June), 85±65 (36-228)μg/m(3) during the growing season (16 June-25 September), and 207±88 (103-310)μg/m(3) during the harvest period (26 September-31 October). PM2.5 accounted for 44%, 56% and 66% of atmospheric PM10 during these periods, respectively. The PM10 diurnal variation showed a distinct peak from 16:00 to 21:00 (LST) during the growing and harvesting seasons, while a gradual increase throughout the daytime until 17:00 was observed during tilling season. Mineral dust elements (Al, Ca, Fe, and Mg) dominated the PM10 chemical composition during the tilling season; OC, NO3(-), SO4(2-) and NH4(+) during the growing season; and carbonaceous species (i.e., OC and EC) during the harvesting season. Our results indicate that the soil particles emitted by farm tillage and organic matter released from straw burning are the two most significant sources of PM10 emissions contributing to the recurring high pollution events in this region. Therefore, development of agricultural PM inventories from soil tillage and straw burning is prioritized to support air quality modeling.

  3. Refractive indices of polymer-dispersed liquid-crystal film materials: Epoxy-based systems

    NASA Astrophysics Data System (ADS)

    Vaz, Nuno A.; Montgomery, G. Paul, Jr.

    1987-10-01

    Polymer-dispersed liquid crystal (PDLC) films are potentially useful in applications requiring electrically controllable light transmission. In these applications, both a high on-state transmittance and a strong off-state attenuation are often needed over a wide operating temperature range. These transmittance characteristics depend strongly on the refractive indices of the materials in the PDLC films. We have measured the temperature dependent refractive indices of typical PDLC film materials and the temperature dependent electro-optic transmittance of a PDLC film composed of liquid crystal microdroplets dispersed in an epoxy matrix. We show that our refractive index measurements can account for all the features in the measured transmittance characteristics and discuss several methods for controlling refractive indices to optimize electro-optic transmittance over an extended temperature range. We have also measured the room temperature refractive indices of mixtures of epoxy resins and hardeners as a function of composition. We discuss the problems associated with predicting the refractive indices of such mixtures in terms of either the volume fractions or mole fractions of the mixture components. These considerations are important in matching refractive indices of droplets and matrix materials to maximize on-state transmittance. The refractive indices of epoxy matrix materials increase monotonically with time during their chemical cure. The measured time dependence can be described by a simple model in which the concentrations of the reacting resin and hardener each decay exponentially in time with their own characteristic time constants while the concentration of the cured polymer increases. Finally, we relate the measured rates of index change with temperature to the coefficients of volume expansion of PDLC film materials; the results are used to discuss the mechanical stability of PDLC films.

  4. Long-term variation of the levels, compositions and sources of size-resolved particulate matter in a megacity in China.

    PubMed

    Tian, Ying-Ze; Wu, Jian-Hui; Shi, Guo-Liang; Wu, Jian-Yu; Zhang, Yu-Fen; Zhou, Lai-Dong; Zhang, Pu; Feng, Yin-Chang

    2013-10-01

    To investigate the long-term trends and variations of the levels, compositions, size distribution and sources of particulate matter (PM), long-term monitoring campaigns of PM10 and PM2.5 were performed in a megacity in China (Chengdu) during the period from 2009 to 2011. The average concentration of PM10 was 172.01±89.80 μg/m(3) and that of PM2.5 was 103.15±59.83 μg/m(3), with an average PM2.5/PM10 of 0.60. Enrichments of the important species indicated that the fractions of crustal elements were higher in PM10 than those in PM2.5, while the abundance of organic carbon (OC) and secondary ions was enriched in the fine PM. Quantitative source apportionments of both PM10 and PM2.5 were performed by PMF. PM10 and PM2.5 in Chengdu were influenced by similar source categories, and their percentage contributions were in the same order: crustal dust was the highest contributor, followed by vehicular exhaust, secondary sulfate, secondary nitrate and cement dust. Crustal dust and cement dust contributed a higher percentage to PM10 than to PM2.5, while vehicular exhaust and secondary particles provided higher percentage contributions to PM2.5. In addition, PMF-HCA was performed to investigate the characteristics of the sources of the clustered samples, identifying three periods: crustal dust dominant-period, secondary sulfate dominant-period and comprehensive source influenced-period. Planting, reduction of precursors, and banning high-emission vehicles should be implemented to control crustal dust, secondary particles and vehicular exhaust in Chengdu. Furthermore, the size-resolved and the period-resolved control would be more effective.

  5. The effect of composition, size, and solubility on acute pulmonary injury in rats following exposure to Mexico city ambient particulate matter samples.

    PubMed

    Snow, Samantha J; De Vizcaya-Ruiz, Andrea; Osornio-Vargas, Alvaro; Thomas, Ronald F; Schladweiler, Mette C; McGee, John; Kodavanti, Urmila P

    2014-01-01

    Particulate matter (PM)-associated metals can contribute to adverse cardiopulmonary effects following exposure to air pollution. The aim of this study was to investigate how variation in the composition and size of ambient PM collected from two distinct regions in Mexico City relates to toxicity differences. Male Wistar Kyoto rats (14 wk) were intratracheally instilled with chemically characterized PM10 and PM2.5 from the north and PM10 from the south of Mexico City (3 mg/kg). Both water-soluble and acid-leachable fractions contained several metals, with levels generally higher in PM10 South. The insoluble and total, but not soluble, fractions of all PM induced pulmonary damage that was indicated by significant increases in neutrophilic inflammation, and several lung injury biomarkers including total protein, albumin, lactate dehydrogenase activity, and γ-glutamyl transferase activity 24 and 72 h postexposure. PM10 North and PM2.5 North also significantly decreased levels of the antioxidant ascorbic acid. Elevation in lung mRNA biomarkers of inflammation (tumor necrosis factor [TNF]-α and macrophage inflammatory protein [MIP]-2), oxidative stress (heme oxygenase [HO]-1, lectin-like oxidized low-density lipoprotein receptor [LOX]-1, and inducibile nitric oxide synthase [iNOS]), and thrombosis (tissue factor [TF] and plasminogen activator inhibitor [PAI]-1), as well as reduced levels of fibrinolytic protein tissue plasminogen activator (tPA), further indicated pulmonary injury following PM exposure. These responses were more pronounced with PM10 South (PM10 South > PM10 North > PM2.5 North), which contained higher levels of redox-active transition metals that may have contributed to specific differences in selected lung gene markers. These findings provide evidence that surface chemistry of the PM core and not the water-soluble fraction played an important role in regulating in vivo pulmonary toxicity responses to Mexico City PM.

  6. Saccharide Composition in Fine and Coarse Particulate Matter and Soils in Central Arizona and Use of Saccharides as Molecular Markers for Source Apportionment

    NASA Astrophysics Data System (ADS)

    Jia, Y.; Clements, A.; Fraser, M.

    2009-04-01

    The desert southwestern United States routinely exceeds health-based standards for coarse particulate matter [1]. PM10 concentrations are high in both urban and rural areas and are believed to originate from fugitive dust emissions from agricultural fields and roads and soil erosion from the surrounding desert locations. Soil together with its associated biota contains a complex mixture of biogenic detritus, including plant detritus, airborne microbes comprised of bacteria, viruses, spores of lichens and fungi, small algae, and protozoan cysts [4][5], which can mostly become airborne when winds are strong enough and soil dry enough to be re-entrained into the atmosphere [3]. Other potential sources to PM10 may include primary biological aerosol particles (PBAPs), given a multitude of flower, grass, and fungal species that thrive in the Sonoran desert and actively release pollens and spores throughout the year [2]. However, because soil and fugitive dust is also believed to contain a large number of these biological particles and is considered as a secondary host of PBAPs [3] [4], the role and contribution of PBAPs as a direct ambient PM source in the desert southwest have not been clearly stated or investigated. In an effort to identify and assess the relative contribution of these and other major PM sources in the southwestern US region, and particularly to assess the contribution from soil and fugitive dust, a series of ambient PM samples and soil samples were collected in Higley, AZ, USA, a suburb of the Phoenix metropolitan area which has seen rapid urban sprawl onto agricultural lands. Because of their suggested ability to track biologically important organic materials from natural environment [4][6][7][8][9][10], saccharides were chosen as the key compounds to trace the release of soil dusts into the atmosphere, and to elucidate other major sources that contribute to the PM levels in this location in the arid southwestern US. To this end, saccharide compounds

  7. Trends of particulate matter (PM2.5) and chemical composition at a regional background site in the Western Mediterranean over the last nine years (2002-2010)

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    The time variability and long term trends of PM2.5 (particulate matter of diameter < 2.5 μm) at various regional background (RB) sites across Europe are studied and interpreted in this work. Data on mean annual levels of PM2.5 measured at Montseny (MSY, North East Spain) and various RB sites in Spain and Europe are evaluated and compared, and subsequently analysed for statistically significant trends. The MSY site registered higher average PM2.5 levels than those measured at a selection of other RB sites across Spain, Portugal, Germany and Scandinavia by percentage compared to the mean of all the stations in these countries, but lower than those measured in Switzerland, Italy and Austria. Reductions in PM2.5 were observed across all stations in Spain and Europe to varying degrees (7-49%). MSY underwent a statistically significant reduction since measurements began, indicating a year-on-year gradual decrease (-3.7 μg m-3, calculated from the final year of data compared to the mean). Similar trends were observed in other RB sites across Spain (-1.9 μg m-3). Reductions recorded in PM2.5 across Europe were varied, with many experiencing gradual, year-on-year decreases (-1.8 μg m-3). These reductions have been attributed to various causes: the introduction and implementation of pollution abatement strategies in EU member states, the effect of the current economic crisis on emissions of PM2.5 and the influence of meteorology observed during the winters of 2009 and 2010. In addition, the North Atlantic Oscillation (NAO), a large scale meteorological phenomenon most prevalent during winter, was observed to influence the frequency of Saharan dust intrusions across the Iberian Peninsula. Chemical composition of PM2.5 at MSY is characterised by high levels of organic matter (OM) and sulphate, followed by crustal material, nitrate and ammonia. Sea Spray and elemental carbon (EC) comprised a minor part of the total PM2.5 mass. Statistical trend analysis was performed on the

  8. Observation of direct and indirect magnetoelectricity in lead free ferroelectric (Na0.5Bi0.5TiO3)-magnetostrictive (CoFe2O4) particulate composite

    NASA Astrophysics Data System (ADS)

    Srinivas, A.; Krishnaiah, R. V.; Karthik, T.; Suresh, P.; Asthana, Saket; Kamat, S. V.

    2012-08-01

    A particulate composite consisting of 65 mol. % Na0.5Bi0.5TiO3 and 35 mol. % CoFe2O4 was synthesized, and it's structure, microstructure, ferroelectric, magnetostrictive, magnetic, and direct/indirect magnetoelectric properties were studied. The composite showed different magnetization behaviour under electrically poled and un-poled conditions. The percentage change in magnetization as a result of poling is approximately -15% at 500 Oe magnetic field. Magnetostriction measurements displayed a value of λ11 = -57 × 10-6 and piezomagnetic coefficient δλ11/δH = 0.022 × 10-6 kOe-1 at 2.2 kOe for the composite. The maximum magnetoelectric output varied from 1350 mV/cm to 2000 mV/cm with change in the electrical poling conditions.

  9. Contrasting composition of terrigenous organic matter in the dissolved, particulate and sedimentary organic carbon pools on the outer East Siberian Arctic Shelf

    NASA Astrophysics Data System (ADS)

    Salvadó, Joan A.; Tesi, Tommaso; Sundbom, Marcus; Karlsson, Emma; Kruså, Martin; Semiletov, Igor P.; Panova, Elena; Gustafsson, Örjan

    2016-11-01

    Fluvial discharge and coastal erosion of the permafrost-dominated East Siberian Arctic delivers large quantities of terrigenous organic carbon (Terr-OC) to marine waters. The composition and fate of the remobilized Terr-OC needs to be better constrained as it impacts the potential for a climate-carbon feedback. In the present study, the bulk isotope (δ13C and Δ14C) and macromolecular (lignin-derived phenols) composition of the cross-shelf exported organic carbon (OC) in different marine pools is evaluated. For this purpose, as part of the SWERUS-C3 expedition (July-September 2014), sediment organic carbon (SOC) as well as water column (from surface and near-bottom seawater) dissolved organic carbon (DOC) and particulate organic carbon (POC) samples were collected along the outer shelves of the Kara Sea, Laptev Sea and East Siberian Sea. The results show that the Lena River and the DOC may have a preferential role in the transport of Terr-OC to the outer shelf. DOC concentrations (740-3600 µg L-1) were 1 order of magnitude higher than POC (20-360 µg L-1), with higher concentrations towards the Lena River plume. The δ13C signatures in the three carbon pools varied from -23.9 ± 1.9 ‰ in the SOC, -26.1 ± 1.2 ‰ in the DOC and -27.1 ± 1.9 ‰ in the POC. The Δ14C values ranged between -395 ± 83 (SOC), -226 ± 92 (DOC) and -113 ± 122 ‰ (POC). These stable and radiocarbon isotopes were also different between the Laptev Sea and the East Siberian Sea. Both DOC and POC showed a depleted and younger trend off the Lena River plume. Further, the Pacific inflow and the sea-ice coverage, which works as a barrier preventing the input of "young" DOC and POC, seem to have a strong influence in these carbon pools, presenting older and more enriched δ13C signatures under the sea-ice extent. Lignin phenols exhibited higher OC-normalized concentrations in the SOC (0.10-2.34 mg g-1 OC) and DOC (0.08-2.40 mg g-1 OC) than in the POC (0.03-1.14 mg g-1 OC). The good

  10. Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites

    DTIC Science & Technology

    2016-03-09

    A - Approved for Public Release 13. SUPPLEMENTARY NOTES 14. ABSTRACT Incorporation of carbon nanotubes (CNTs) into epoxy-based composites for...materials with higher moduli and strength characteristics. 15. SUBJECT TERMS Molecular Dynamics, Carbon Nanotubes , Multi-scale Modeling, Micromechanics...Gregory M. Odegard Michigan Technological University Introduction This project was inspired from the AFOSR-sponsored workshop “ Nanotube

  11. 3D-printing of lightweight cellular composites.

    PubMed

    Compton, Brett G; Lewis, Jennifer A

    2014-09-10

    A new epoxy-based ink is reported, which enables 3D printing of lightweight cellular composites with controlled alignment of multiscale, high-aspectratio fiber reinforcement to create hierarchical structures inspired by balsa wood. Young's modulus values up to 10 times higher than existing commercially available 3D-printed polymers are attainable, while comparable strength values are maintained.

  12. Bonding Strength Properties of Adhesively-Timber Joint with Thixotropic and Room Temperature Cured Epoxy Based Adhesive Reinforced with Nano- and Micro-particles

    NASA Astrophysics Data System (ADS)

    Ahmad, Z.; Ansell, M. P.; Smedley, D.

    2011-02-01

    This research work is concerned with in situ bonded-in timber connection using pultruded rod; where the manufacturing of such joint requires adhesive which can produce thick glue-lines and does not allow any use of pressure and heat. Four types of thixotropic (for ease application) and room temperature cured epoxy based were used namely CB10TSS (regarded as standards adhesive), Nanopox (modification of CB10TSS with addition of nanosilica), Albipox (modification of CB10TSS with addition of liquid rubber) and Timberset (an epoxy-based adhesive with addition of micro-size ceramic particles). The quality of the adhesive bonds was accessed using block shear test in accordance with ASTM D905. The bond strength depends on how good the adhesive wet the timber surface. Therefore the viscosity and contact angle was also measured. The nano- and microfiller additions increased the bond strength significantly. The viscosity correlates well with contact angle measurements where lower viscosities are associated with lower contact angles. However contact angle contradicts with measured strength and wettability.

  13. Trends of particulate matter (PM2.5) and chemical composition at a regional background site in the Western Mediterranean over the last nine years (2002-2010)

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    The time variability and long term trends of PM2.5 (particulate matter of diameter <2.5 μm) at various regional background (RB) sites across Europe are studied and interpreted in this work. Long-term trends of PM2.5 concentrations are relatively scarce across Europe, with few studies outlining the changes measured in PM2.5 concentrations over a significant period of time. To this end, data on mean annual levels of PM2.5 measured at Montseny (MSY, North East Spain) and various RB sites in Spain and Europe are evaluated and compared, and subsequently analysed for statistically significant trends. The MSY site registered higher average PM2.5 levels than those measured at a selection of other RB sites across Spain, Portugal, Germany and Scandinavia, but lower than those measured in Switzerland, Italy and Austria. Reductions in PM2.5 were observed across all stations in Spain and Europe to varying degrees. MSY underwent a statistically significant reduction since measurements began, indicating a year-on-year gradual decrease (-3.7 μg m-3, calculated from the final year of data compared to the mean). Similar trends were observed in other RB sites across Spain (-1.9 μg m-3). Reductions recorded in PM2.5 across Europe were varied, with many experiencing gradual, year-on-year decreases (-1.8 μg m-3). These reductions have been attributed to various causes: the introduction and implementation of pollution abatement strategies in EU member states, the effect of the current economic crisis on emissions of PM2.5 and the influence of anomalous meteorology observed during the winters of 2009 and 2010. The North Atlantic Oscillation (NAO), a large scale meteorological phenomenon most prevalent during winter, was observed to influence the frequency of Saharan dust intrusions across the Iberian Peninsula. Chemical composition of PM2.5 at MSY is characterised by high levels of organic matter (OM) and sulphate, followed by crustal material, nitrate and ammonia. Sea Spray and

  14. Magnetoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 - CoFe2O4 particulate composites

    NASA Astrophysics Data System (ADS)

    Paul Praveen, J.; Vinitha Reddy, M.; Das, Dibakar

    2016-05-01

    0.7[(Ba0.85Ca0.15)(Zr0.1Ti0.9)O3)]-0.3[CoFe2O4] multiferroic particulate ceramic composite with (0-3) connectivity has been synthesized by wet chemical methods. BCZT-CFO composite showed both polarization-electric field and magnetic hysteresis loops simultaneously at room temperature. A high dielectric constant of 2160 and tangent loss factor of 0.6 has been obtained. Magnetoelectric (ME) voltage coefficient (αME =dE/dH) of the composite was measured as a function of applied d.c magnetic field at different frequencies. At resonance frequency (365kHz) the composite showed a maximum αME of 102mV/cm.Oe. It was observed that the transverse ME coefficient is 1.8 times higher than the longitudinal ME coefficient. The magnetoelectric properties of this composite has been studied in detail in this work and correlated with its structure.

  15. Hyphenation of a carbon analyzer to photo-ionization mass spectrometry to unravel the organic composition of particulate matter on a molecular level.

    PubMed

    Grabowsky, Jana; Streibel, Thorsten; Sklorz, Martin; Chow, Judith C; Watson, John G; Mamakos, Athanasios; Zimmermann, Ralf

    2011-12-01

    The carbonaceous fraction of airborne particulate matter (PM) is of increasing interest due to the adverse health effects they are linked to. Its analytical ascertainment on a molecular level is still challenging. Hence, analysis of carbonaceous fractions is often carried out by determining bulk parameters such as the overall content of organic compounds (OC) and elemental carbon (EC) as well as the total carbon content, TC (sum of OC and EC), however, no information about the individual substances or substance classes, of which the single fractions consist can be obtained. In this work, a carbon analyzer and a photo-ionization time-of-flight mass spectrometer (PI-TOF-MS) were hyphenated to investigate individual compounds especially from the OC fractions. The carbon analyzer enables the stepwise heating of particle samples and provides the bulk parameters. With the PI-TOF-MS, it is possible to detect the organic compounds released during the single-temperature steps due to soft ionization and fast detection of the molecular ions. The hyphenation was designed, built up, characterized by standard substances, and applied to several kinds of samples, such as ambient aerosol, gasoline, and diesel emission as well as wood combustion emission samples. The ambient filter sample showed a strong impact of wood combustion markers. This was revealed by comparison to the product pattern of the similar analysis of pure cellulose and lignin and the wood combustion PM. At higher temperatures (450 °C), a shift to smaller molecules occurred due to the thermal decomposition of larger structures of oligomeric or polymeric nature comparable to lignocelluloses and similar oxygenated humic-like substances. Finally, particulate matter from gasoline and diesel containing 10% biodiesel vehicle exhaust has been analyzed. Gasoline-derived PM exhibited large polycyclic aromatic hydrocarbons, whereas diesel PM showed a much higher total organic content. The detected pattern revealed a strong

  16. Seasonal survey of the composition and degradation state of particulate organic matter in the Rhône River using lipid tracers

    NASA Astrophysics Data System (ADS)

    Galeron, M.-A.; Amiraux, R.; Charriere, B.; Radakovitch, O.; Raimbault, P.; Garcia, N.; Lagadec, V.; Vaultier, F.; Rontani, J.-F.

    2015-03-01

    Lipid tracers including fatty acids, hydroxyacids, n-alkanols, sterols and triterpenoids were used to determine the origin and fate of suspended particulate organic matter (POM) collected in the Rhône River (France). This seasonal survey (April 2011 to May 2013) revealed a year-round strong terrestrial higher-plant contribution to the particulate organic matter (POM), with significant algal inputs observed in March and attributed to phytoplanktonic blooms likely dominated by diatoms. Major terrigenous contributors to our samples are gymnosperms, and more precisely their roots and stems, as evidenced by the presence of high proportions of ω-hydroxydocosanoic acid (a suberin biomarker). The high amounts of coprostanol detected clearly show that the Rhône River is significantly affected by sewage waters. Specific sterol degradation products were quantified and used to assess the part of biotic and abiotic degradation of POM within the river. Higher-plant-derived organic matter appears to be mainly affected by photo-oxidation and autoxidation (free radical oxidation), while organic matter of mammal or human origin, evidenced by the presence of coprostanol, is clearly more prone to bacterial degradation. Despite the involvement of an intense autoxidation-inducing homolytic cleavage of peroxy bonds, a significant proportion of hydroperoxides is still intact in higher plant debris. These compounds could affect the degradation of terrestrial material by inducing an intense autoxidation upon its arrival at sea.

  17. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

  18. Particulate Air Pollution: The Particulars

    ERIC Educational Resources Information Center

    Murphy, James E.

    1973-01-01

    Describes some of the causes and consequences of particulate air pollution. Outlines the experimental procedures for measuring the amount of particulate materials that settles from the air and for observing the nature of particulate air pollution. (JR)

  19. Particulate matter fugitive dusts

    SciTech Connect

    Not Available

    1988-01-01

    Topics covered in this conference include: Review of EPA's cost/benefit analysis for additional regulation of surface coal mines; Particulate monitoring on the Kilauea East Rift, Hawaii, and The MEDUSA sampling system: case histories in the measurement of particulate matter with wide spectrum analysis.

  20. Airborne particulate discriminator

    DOEpatents

    Creek, Kathryn Louise; Castro, Alonso; Gray, Perry Clayton

    2009-08-11

    A method and apparatus for rapid and accurate detection and discrimination of biological, radiological, and chemical particles in air. A suspect aerosol of the target particulates is treated with a taggant aerosol of ultrafine particulates. Coagulation of the taggant and target particles causes a change in fluorescent properties of the cloud, providing an indication of the presence of the target.

  1. SOUTHERN FINE PARTICULATE MONITORING PROJECT

    SciTech Connect

    Ashley D. Williamson

    2001-07-01

    This is the third quarterly progress report of the ''Southern Fine Particulate Monitoring Project'', funded by the U.S. Department of Energy's National Energy Technology Laboratory under DOE Cooperative Agreement No. DE-FC26-00NT40770 to Southern Research Institute (SRI). In this two year project SRI will conduct detailed studies of ambient fine particulate matter in the Birmingham, AL metropolitan area. Project objectives include: Augment existing measurements of primary and secondary aerosols at an established urban southeastern monitoring site; Make a detailed database of near-continuous measurements of the time variation of fine particulate mass, composition, and key properties (including particle size distribution); Apply the measurements to source attribution, time/transport properties of fine PM, and implications for management strategies for PM{sub 2.5}; and Validate and compare key measurement methods used in this study for applicability within other PM{sub 2.5} research by DOE-FE, EPA, NARSTO, and others. During the third project quarter, the new SRI air monitoring shelter and additional instruments were installed at the site. Details include: Installation of Radiance Research M903 Nephelometer; Installation of SRI air monitoring shelter at North Birmingham Site; Relocation of instruments from SEARCH shelter to SRI shelter; Installation of Rupprecht & Patashnick 8400 Sulfate Monitor; Assembly and initial laboratory testing for particulate sulfate monitor of Harvard design; Efficiency testing of particle sizing instrument package at SRI lab; Preparation for the Eastern Supersite July measurement intensive program; and Continued monitoring with TEOM and particle sizing instruments.

  2. Effective thermal conductivity of metal and non-metal particulate composites with interfacial thermal resistance at high volume fraction of nano to macro-sized spheres

    SciTech Connect

    Faroughi, Salah Aldin; Huber, Christian

    2015-02-07

    In this study, we propose a theoretical model to compute the effective thermal conductivity of metal and dielectric spherical particle reinforced composites with interfacial thermal resistance. We consider a wide range of filler volume fraction with sizes ranging from nano- to macro-scale. The model, based on the differential effective medium theory, accounts for particle interactions through two sets of volume fraction corrections. The first correction accounts for a finite volume of composite and the second correction introduces a self-crowding factor that allows us to develop an accurate model for particle interaction even for high volume fraction of fillers. The model is examined to other published models, experiments, and numerical simulations for different types of composites. We observe an excellent agreement between the model and published datasets over a wide range of particle volume fractions and material properties of the composite constituents.

  3. Structural Performance of Cylindrical Pressure Housings of Different Ceramic Compositions Under External Pressure Loading. Part 4. Silicon Carbide Particulate Reinforced Alumina Ceramic

    DTIC Science & Technology

    1993-12-01

    this composition is manufactured by a pro- significant weight penalty. Pressure testing has prietary directed metal oxidation ( DIMOX ) demonstrated that...the DIMOX - process be scaled up for fabrication successfully and repeatably cast 12-inch-OD by of greater than 20-inch-OD cylinders and hemi-I 18...inch-long cylinders from its 90-X-089 SiC/ spheres. The benefits of the DIMOX " process will AI2 03/AI composition. All twelve cylinders passed be of

  4. Method of dispersing particulate aerosol tracer

    DOEpatents

    O'Holleran, Thomas P.

    1988-01-01

    A particulate aerosol tracer which comprises a particulate carrier of sheet silicate composition having a particle size up to one micron, and a cationic dopant chemically absorbed in solid solution in the carrier. The carrier is preferably selected from the group consisting of natural mineral clays such as bentonite, and the dopant is selected from the group consisting of rare earth elements and transition elements. The tracers are dispersed by forming an aqueous salt solution with the dopant present as cations, dispersing the carriers in the solution, and then atomizing the solution under heat sufficient to superheat the solution droplets at a level sufficient to prevent reagglomeration of the carrier particles.

  5. Particulate matter sensor with a heater

    DOEpatents

    Hall, Matthew

    2011-08-16

    An apparatus to detect particulate matter. The apparatus includes a sensor electrode, a shroud, and a heater. The electrode measures a chemical composition within an exhaust stream. The shroud surrounds at least a portion of the sensor electrode, exclusive of a distal end of the sensor electrode exposed to the exhaust stream. The shroud defines an air gap between the sensor electrode and the shroud and an opening toward the distal end of the sensor electrode. The heater is mounted relative to the sensor electrode. The heater burns off particulate matter in the air gap between the sensor electrode and the shroud.

  6. Microstructure development in particulate ceramic coatings

    SciTech Connect

    Kim, Y.J.; Wara, N.M.; Francis, L.F.; Velamakanni, B.V.

    1994-12-31

    Microstructure development in particulate coatings is influenced by the particle-particle interactions and additional mechanisms, such as reaction and phase separation, which are driven by compositional changes in a coating during deposition and drying. The effect of agglomeration rate on microstructure uniformity and pore content is demonstrated using coatings produced from aqueous alumina dispersions. The addition of cellulose acetate and acetone to the alumina dispersion leads to phase separation and a coating with large cylindrical pores. The formation of particles by reactions during deposition is also discussed. The pore content of particulate titania coatings prepared in this way can be varied from 30 to 60% by changing the coating conditions.

  7. Fluidizing device for solid particulates

    DOEpatents

    Diebold, J.P.; Scahill, J.W.

    A flexible whip suspended in a hopper is caused to impact against fibrous and irregularly shaped particulates in the hopper to fluidize the particulates and facilitate the flow of the particulates through the hopper. The invention provides for the flow of particulates at a substantially constant mass flow rate and uses a minimum of energy.

  8. Structural performance of cylindrical pressure housings of different ceramic compositions under external pressure loading. Part 4. Silicon carbide particulate reinforced alumina ceramic. Final technical report

    SciTech Connect

    Kurchubasche, R.R.; Johnson, R.P.; Stachiw, J.D.; Johnson, T.A.

    1993-12-01

    Twelve 12-inch-OD by 18-inch-long by 0.412-inch-thick silicon-carbide particulate reinforced alumina-ceramic cylinders were fabricated, assembled, and pressure tested to determine their suitability for use as external pressure-resistant housings for underwater applications. The material, designated 90-X-089, is made by Lanxide Corporation (Newark, DE) by a proprietary directed metal oxidation (DIMOX) (TM) process. The primary advantages of this material are its high compressive strength, high elastic modulus, high fracture toughness, low specific gravity, and ability to be cast in near net shapes, eliminating the need for expensive diamond grinding. Pressure test results are presented along with strain gage data, cyclic fatigue-life data, and acoustic emissions. Conclusions regarding the suitability of the material for application to pressure housings for underwater applications are presented along with a comparison to WESGO's AL-600 96-percent alumina ceramic, which was chosen as a base of comparison for various advanced materials being evaluated under the same program. Recommendations for design implementation, nondestructive evaluation, and further research are made.

  9. Seasonal variations in the chemical composition of particulate matter: a case study in the Po Valley. Part II: concentration and solubility of micro- and trace-elements.

    PubMed

    Canepari, S; Astolfi, M L; Farao, C; Maretto, M; Frasca, D; Marcoccia, M; Perrino, C

    2014-03-01

    Size distribution (fine and coarse fraction) and solubility distribution (extracted and residual fraction) of 20 elements (As, Ba, Be, Cd, Co, Cu, Fe, Li, Mn, Pb, Ni, Rb, S, Sb, Se, Sn, Sr, Ti, Tl, V) in atmospheric particulate matter (PM) were determined during a 5-year field study carried out in the Po Valley (peri-urban area of Ferrara, in Northern Italy). By studying the contribution of the two size fractions and the two solubility fractions to the atmospheric concentration of each element, it was possible to obtain interesting information about the variability of PM sources, to assess the role played by atmospheric stability in determining pollution episodes, and to obtain an estimate of the bio-accessible fraction. Atmospheric stability is confirmed to be one of the main causes of atmospheric pollution in this area and is to be responsible for the pronounced winter increase in both PM and elemental concentration. Long-range transport of natural and polluted air masses caused temporary increases in PM and elemental concentration, while local industrial emission seemed to play a secondary role. Regulated elements were well below their concentration limit, but many toxic elements were in the form of fine particles and soluble chemical species, more accessible to the environment, and the human body.

  10. CHARACTERIZATION OF PARTICULATE MATTER FROM PHOENIX, ARIZONA, USING RAY FLUORESCENCE AND COMPUTER-CONTROLLED SCANNING ELECTRON MICROSCOPY

    EPA Science Inventory

    Numerous epidemiological studies have found associations between airborne particulate matter measured at community monitors and increased mortality and morbidity. Chemical and physical characteristics of particulate matter (e.g., elemental composition, size) and source identifi...

  11. Modeling of Particulate Emissions

    DTIC Science & Technology

    2011-12-01

    coagulation oxidation.... carbonization 14 Modeling Particulate Emissions Soot Formation Kinetics 2 1016 1 ]HC[kdt dS = Inception: Dimerization of...simulated with peak size for surface growth Sectional Conservation Equation 16 Modeling Particulate Emissions Soot Kinetics Based on OH, O2 and...and empirical tuning to NOx, CO emissionsFuel-spray shear layer Recirculation zones Quench zones Burn-out zones Full set of reaction kinetics and

  12. Durability of lanxide-silicon carbide-particulate composite in simulated advanced glass-melter heat-exchanger ambients. Topical report, June 1, 1988-August 31, 1991

    SciTech Connect

    Kern, W.A.; Tressler, R.E.; McNallan, M.J.

    1991-08-01

    Ceramics matrix composites fabricated by the Dimox process may have applications as heat exchanger materials in high temperature corrosive environments such as the those encountered in the glass industry.The oxidation and corrosion properties of these composites have been investigated in the temperature range of 1000 deg. to 1300 deg. C. The materials experience rapid oxidation in air leading to mass increases of 100 to 140 mg/sq.cm in less than 1 h. This occurs oxidation of residual metal in the composite to form Al/Al2O3 deposits on the surface. Metal-free coatings grown on the surfaces of the tiles interfered with the oxidation process, but oxide nodules could grow through flaws in the coatings. Subsequently, there is little further attack.

  13. Effects of breadfruit seed hull ash on the microstructures and properties of Al-Si-Fe alloy/breadfruit seed hull ash particulate composites

    NASA Astrophysics Data System (ADS)

    Atuanya, C. U.; Ibhadode, A. O. A.; Dagwa, I. M.

    2012-01-01

    The microstructures and properties of Al-Si-Fe alloy matrix composites reinforced with different weight fractions of breadfruit seed hull (husk) ash particles of size 500 nm were investigated. Six (6) different weight fractions of breadfruit seed hull ash particles were added to aluminium alloy matrix using a double stir-casting method. Microstructural analysis shows that with the increase of the reinforcement weight fraction, the matrix grain size decreases. The mechanical properties of the composites are improved over the matrix materials, except for the slightly decrease of the impact energy. Fracture surface examination indicates that there is a good interfacial bonding between the aluminium alloy matrix and the breadfruit seed hull ash particles and that fracture initiation does not occur at the particle-matrix interface. Hence, incorporation of breadfruit seed hull ash particles in aluminium matrix can lead to the production of low cost aluminium composites with improved hardness and strength. These composites can find applications in automotive components where light weight materials are required with good stiffness and strength.

  14. Effect of Cross-linking Density on Creep and Recovery Behavior in Epoxy-Based Shape Memory Polymers (SMEPs) for Structural Applications

    NASA Astrophysics Data System (ADS)

    Rao, Kavitha V.; Ananthapadmanabha, G. S.; Dayananda, G. N.

    2016-12-01

    Epoxy-based shape memory polymers (SMEPs) are gaining importance in the area of aerospace structures due to their high strength and stiffness which is a primary requirement for an SMEP in structural applications. The understanding of viscoelastic behavior of SMEPs is very essential to assess their shape memory effect. In the present work, three types of SMEPs with varying cross-linking densities were developed by curing an aromatic epoxy resin with aliphatic amines. Glass transition temperature ( T g) was measured for these SMEPs using advanced rheometric expansion system, and from the T g measurements, a range of temperatures from glassy to rubbery regimes were chosen. At selected temperatures, creep-recovery tests were performed in order to evaluate the viscoelastic behavior of SMEPs and also to investigate the effect of temperature on creep-recovery. Further, a three-parameter viscoelastic model (Zener) was used to fit the data obtained from experiments. Model parameters like moduli of the springs and viscosity of the dashpot were evaluated by curve fitting. Results revealed that Zener model was well suited to describe the viscoelastic behavior of SMEPs as a function of test temperatures.

  15. Nighttime aqueous-phase secondary organic aerosols in Los Angeles and its implication for fine particulate matter composition and oxidative potential

    NASA Astrophysics Data System (ADS)

    Saffari, Arian; Hasheminassab, Sina; Shafer, Martin M.; Schauer, James J.; Chatila, Talal A.; Sioutas, Constantinos

    2016-05-01

    Recent investigations suggest that aqueous phase oxidation of hydrophilic organic compounds can be a significant source of secondary organic aerosols (SOA) in the atmosphere. Here we investigate the possibility of nighttime aqueous phase formation of SOA in Los Angeles during winter, through examination of trends in fine particulate matter (PM2.5) carbonaceous content during two contrasting seasons. Distinctive winter and summer trends were observed for the diurnal variation of organic carbon (OC) and secondary organic carbon (SOC), with elevated levels during the nighttime in winter, suggesting an enhanced formation of SOA during that period. The nighttime ratio of SOC to OC was positively associated with the relative humidity (RH) at high RH levels (above 70%), which is when the liquid water content of the ambient aerosol would be high and could facilitate dissolution of hydrophilic primary organic compounds into the aqueous phase. Time-integrated collection and analysis of wintertime particles at three time periods of the day (morning, 6:00 a.m.-9:00 a.m.; afternoon, 11:00 a.m.-3:00 p.m.; night, 8:00 p.m.-4:00 a.m.) revealed higher levels of water soluble organic carbon (WSOC) and organic acids during the night and afternoon periods compared to the morning period, indicating that the SOA formation in winter continues throughout the nighttime. Furthermore, diurnal trends in concentrations of semi-volatile organic compounds (SVOCs) from primary emissions showed that partitioning of SVOCs from the gas to the particle phase due to the decreased nighttime temperatures cannot explain the substantial OC and SOC increase at night. The oxidative potential of the collected particles (quantified using a biological macrophage-based reactive oxygen species assay, in addition to the dithiothreitol assay) was comparable during afternoon and nighttime periods, but higher (by at least ∼30%) compared to the morning period, suggesting that SOA formation processes possibly

  16. Production of carbon nano-tubes via CCVD method and their corrosion protection performance in epoxy based coatings

    NASA Astrophysics Data System (ADS)

    Raza, M. A.; Ghauri, F. A.; Awan, M. S.; Farooq, A.; Ahmad, R.

    2016-08-01

    Good yield of carbon products was obtained by catalytic chemical vapor deposition (CCVD) technique using 100-500mg of ferrocene catalyst at temperature of 900 °C and acetylene flow rate of 150-200cc/min. The effects of amount of ferrocene, temperature and hydrocarbons precursors on the yield of carbon nanomaterial's was calculated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) andenergy- dispersive X-ray spectroscopy (EDS). Good yield of carbon nanomaterials primarily consisted of carbon nanotubes (CNTs) and carbon nanoparticles was obtained. CNTs obtained after purification were dispersed in epoxy resin to produce composite coatings which were coated on stainless steel 316L. The coated stainless steel samples’ corrosion behavior was studied using open circuit potential (OCP), cyclic polarization and electrochemical impedance spectroscopy (EIS) techniques. Results showed that epoxy coating containing 4 wt. % of CNTs offered improved corrosion resistance to stainless steel.

  17. Oxidation and corrosion of SiC{sub (particulate)}/Al/Al{sub 2}O{sub 3} composites in sodium silicate at elevated temperatures

    SciTech Connect

    Kern, W.A.; Tressler, R.E.; McNallan, M.J.

    1996-07-01

    Ceramic-matrix composites (CMCs) fabricated by the directed metal oxidation process (Dimox{trademark}) may have applications in heat exchangers in high-temperature corrosive environments such as those in the glass industry. The oxidation and corrosion properties of such CMCs with and without preformed metal-free surface layers have been investigated in the temperature range of 1,000--1,300 C. The untreated CMCs experienced rapid oxidation in air leading to mass increases of 100 to 140 mg/cm{sup 2} in less than 1 h. This occurred by oxidation of residual metal in the composite to form Al/Al{sub 2}O{sub 3} deposits on the surface. After the initial formation of the oxidation product, there is little further reaction during up to 300-h exposures to oxidizing atmospheres. Experimental composite coupons with metal-free surfaces were resistant to oxidation except for localized events associated with flaws. Small amounts of sodium silicate (2 to 40 mg/cm{sup 2}) painted on the surfaces produced no corrosive effects on any of the specimens. Dynamic corrosion experiments, in which a continuous mist of sodium silicate was sprayed onto the surfaces, produced corrosion at 1,300 C.

  18. Atmospheric particulate measurements in Norfolk, Virginia

    NASA Technical Reports Server (NTRS)

    Storey, R. W., Jr.; Sentell, R. J.; Woods, D. C.; Smith, J. R.; Harris, F. S., Jr.

    1975-01-01

    Characterization of atmospheric particulates was conducted at a site near the center of Norfolk, Virginia. Air quality was measured in terms of atmospheric mass loading, particle size distribution, and particulate elemental composition for a period of 2 weeks. The objectives of this study were (1) to establish a mean level of air quality and deviations about this mean, (2) to ascertain diurnal changes or special events in air quality, and (3) to evaluate instrumentation and sampling schedules. Simultaneous measurements were made with the following instruments: a quartz crystal microbalance particulate monitor, a light-scattering multirange particle counter, a high-volume air sampler, and polycarbonate membrane filters. To assess the impact of meteorological conditions on air quality variations, continuous data on temperature, relative humidity, wind speed, and wind direction were recorded. Particulate elemental composition was obtained from neutron activation and scanning electron microscopy analyses of polycarbonate membrane filter samples. The measured average mass loading agrees reasonably well with the mass loadings determined by the Virginia State Air Pollution Control Board. There are consistent diurnal increases in atmospheric mass loading in the early morning and a sample time resolution of 1/2 hour seems necessary to detect most of the significant events.

  19. Planar waveguide Bragg grating sensors for composite monitoring

    NASA Astrophysics Data System (ADS)

    Teigell Benéitez, Nuria; Missinne, Jeroen; Chiesura, Gabriele; Luyckx, Geert; Degrieck, Joris; Van Steenberge, Geert

    2016-04-01

    Composite materials are extensively used in a wide array of application markets by virtue of their strength, stiffness and lightness. Many composite structures are replaced today not only after failure but also before, for precautionary reasons. Adding optical sensing intelligence to these structures not only prolongs their lifetime but also significantly reduces the use of raw materials and energy. The use of optical based sensors offer numerous advantages i.e. integrability, high sensitivity, compactness and electromagnetic immunity. Most sensors integrated in composites are based on silica fibers with Bragg gratings. However, polymers are an interesting alternative because they present several advantages. They have high values in the opticalconstants involved in sensing, are cost-effective and allow larger elongations than silica. Moreover, planar optical waveguides represent an interesting approach to be further integrated e.g. in circuits. We present a comparison between Ormocer®-based and epoxy-based polymer waveguide Bragg grating sensors. Both polymers were screened for their compatibility with composite production processes and for their sensitivity to measure temperature and stress. Ormocer®-based sensors were found to exhibit a very high sensitivity (-250 pm/°C) for temperature sensing, while the epoxy-based sensors, although less sensitive (-90 pm/°C) were more compatible with the epoxy-based composite production process. In terms of sensitivity to measure stress, both materials were found to be analogous with measured values of (2.98 pm/μepsilon) for the epoxy-based and (3.00 pm/μepsilon) for Ormocer®-based sensors.

  20. Particulate Release From Nanoparticle-Loaded Shape Memory Polymer Foams.

    PubMed

    Nathan, Adam L; Fletcher, Grace K; Monroe, Mary Beth B; Hwang, Wonjun; Herting, Scott M; Hasan, Sayyeda M; Keller, Brandis K; Maitland, Duncan J

    2017-03-01

    Highly porous, open-celled shape memory polymer (SMP) foams are being developed for a number of vascular occlusion devices. Applications include abdominal aortic and neurovascular aneurysm or peripheral vascular occlusion. A major concern with implanting these high surface area materials in the vasculature is the potential to generate unacceptable particulate burden, in terms of number, size, and composition. This study demonstrates that particulate numbers and sizes in SMP foams are in compliance with limits stated by the most relevant standard and guidance documents. Particulates were quantified in SMP foams as made, postreticulation, and after incorporating nanoparticles intended to increase material toughness and improve radiopacity. When concentrated particulate treatments were administered to fibroblasts, they exhibited high cell viability (100%). These results demonstrate that the SMP foams do not induce an unacceptable level of risk to potential vascular occlusion devices due to particulate generation.

  1. ADVANCED HYBRID PARTICULATE COLLECTOR

    SciTech Connect

    Stanley Miller; Rich Gebert; William Swanson

    1999-11-01

    A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the US Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in a manner that has not been done before. The AHPC concept consists of a combination of fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two collection methods, both in the particulate collection step and in the transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emission with conventional ESPs, and it solves the problem of reentrainment and collection of dust in conventional baghouses. The AHPC is currently being tested at the 2.7-MW scale at the Big Stone power station.

  2. Void/particulate detector

    DOEpatents

    Claytor, Thomas N.; Karplus, Henry B.

    1985-01-01

    Voids and particulates are detected in a flowing stream of fluid contained in a pipe by a detector which includes three transducers spaced about the pipe. A first transducer at a first location on the pipe transmits an ultrasonic signal into the stream. A second transducer detects the through-transmission of the signal at a second location and a third transducer at a third location upstream from the first location detects the back-scattering of the signal from any voids or particulates. To differentiate between voids and particulates a fourth transducer is positioned at a fourth location which is also upstream from the first location. The back-scattered signals are normalized with the through-transmission signal to minimize temperature fluctuations.

  3. Influence of seasonality, air mass origin and particulate matter chemical composition on airborne bacterial community structure in the Po Valley, Italy.

    PubMed

    Innocente, Elena; Squizzato, Stefania; Visin, Flavia; Facca, Chiara; Rampazzo, Giancarlo; Bertolini, Valentina; Gandolfi, Isabella; Franzetti, Andrea; Ambrosini, Roberto; Bestetti, Giuseppina

    2017-03-28

    The integration of chemical and biological data in aerosol studies represents a new challenge in atmospheric science. In this perspective it will be possible to gain a clearer and deeper comprehension of biogeochemical cycles in the atmosphere. In this view, this study aimed to investigate the relationships occurring between bacterial populations and PM chemical composition in one of the most polluted and urbanized areas in Europe: the Po Valley (Italy). Moreover, seasonality, long- and short-range transports were also evaluated to investigate the influence on airborne bacterial communities. PM samples were collected in two cities of the Po Valley (Milan and Venice) characterized by different meteorological conditions and atmospheric pollutant sources. Samples were analysed for water-soluble inorganic ions (WSIIs) and bacterial community structure. Chemical and biological data were jointly processed by using redundancy discriminate analysis (RDA), while the influence of atmospheric circulation was evaluated by using wind ground data and back-trajectories analysis. Results showed strong seasonal shifts of bacterial community structure in both cities, while a different behaviour was observed for air mass circulation at Milan ad Venice sites: long-range transport significantly affected bacterial populations in Milan whereas local ground wind had more influence in the Venice area. Moreover, difference in taxonomic composition can be mostly addressed to the characteristics of sampling sites. This evidence could suggest that, while PM composition is influenced by long-range transport, bacterial populations are affected, besides transport, by other factors (i.e., season and sampling site location). This perspective allow to better understand and explain airborne bacterial community behaviour.

  4. Microwave regenerated particulate trap

    SciTech Connect

    McDonald, A.C. Jr.; Yonushonis, T.M.; Haberkamp, W.C.; Mako, F.; Len, L.K,; Silberglitt, R.; Ahmed, I.

    1997-12-31

    It has been demonstrated that a fibrous particulate filter can extract particulate matter from the diesel exhaust. However, additional engineering efforts remains to achieve the design target of 90%. It has also be shown that with minor modifications magnetrons produced for home ovens can endure a simulated diesel operating environment. Much work remains to develop a robust product ready to complete extensive engine testing and evaluation. These efforts include: (1) additional environmental testing of magnetrons; (2) vibration testing of the filter in the housing; (3) evaluating alternative methods/designs to seal the center bore; and (4) determining the optimum coating thickness that provides sufficient structural integrity while maintaining rapid heating rates.

  5. Characterization of particulate organic matter in the Lena River Delta and adjacent nearshore zone, NE Siberia - Part 1: Lignin-derived phenol compositions

    NASA Astrophysics Data System (ADS)

    Winterfeld, M.; Goñi, M. A.; Just, J.; Hefter, J.; Mollenhauer, G.

    2014-10-01

    The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OM) from its vast catchment area to the coastal zone of the Laptev Sea and the Arctic Ocean. The permafrost soils of its far south stretching catchment, which store huge amounts of OM, will most likely respond differently to climate warming and remobilize previously frozen OM with distinct properties specific for the source vegetation and soil. To characterize the material discharged by the Lena River, we analyzed the lignin phenol composition in total suspended matter (TSM) from surface water collected in spring and summer, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex), and plant samples. Our results show that lignin-derived cinnamyl:vanillyl (C/V) and syringyl:vanillyl (S/V) ratios are >0.14 and 0.25, respectively, in TSM and surface sediments, whereas in delta soils they are >0.16 and >0.51, respectively. These lignin compositions are consistent with significant inputs of organic matter from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. We applied a simple linear mixing model based on the C/V and S/V ratios and the results indicate the organic matter in delta TSM samples and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm material, which is primarily derived from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small catchment area covered by tundra (∼12%), the input is substantial and tundra-derived OM input is likely to increase in a warming Arctic. The similar and high acid to aldehyde ratios of vanillyl and syringyl (Ad/AlV, S) in Lena Delta summer TSM (>0.7 and >0.5, respectively) and Buor Khaya Bay surface sediments (>1.0 and >0.9, respectively) suggest that the OM is highly degraded and Lena River summer TSM could

  6. Characterization of particulate organic matter in the Lena River delta and adjacent nearshore zone, NE Siberia - Part 2: Lignin-derived phenol compositions

    NASA Astrophysics Data System (ADS)

    Winterfeld, M.; Goñi, M. A.; Just, J.; Hefter, J.; Mollenhauer, G.

    2015-04-01

    The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OM) from its vast catchment area to the coastal zone of the Laptev Sea and the Arctic Ocean. The permafrost soils of its far south-stretching catchment, which store huge amounts of OM, will most likely respond differently to climate warming and remobilize previously frozen OM with distinct properties specific for the source vegetation and soil. To characterize the material discharged by the Lena River, we analyzed the lignin phenol composition in total suspended matter (TSM) from surface water collected in spring and summer, surface sediments from Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex), and plant samples. Our results show that lignin-derived cinnamyl : vanillyl (C / V) and syringyl : vanillyl (S / V) ratios are > 0.14 and 0.25, respectively, in TSM and surface sediments, whereas in delta soils they are > 0.16 and > 0.51, respectively. These lignin compositions are consistent with significant inputs of organic matter from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. We applied a simple linear mixing model based on the C / V and S / V ratios, and the results indicate the organic matter in delta TSM samples and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm material, which is primarily derived from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small catchment area covered by tundra (~ 12%), the input is substantial and tundra-derived OM input is likely to increase in a warming Arctic. The similar and high acid to aldehyde ratios of vanillyl and syringyl (Ad / AlV, S) in Lena Delta summer TSM (> 0.7 and > 0.5, respectively) and Buor Khaya Bay surface sediments (> 1.0 and > 0.9, respectively) suggest that the OM is highly degraded and Lena River

  7. Fluidizing device for solid particulates

    DOEpatents

    Diebold, J.P.; Scahill, J.W.

    1984-06-27

    A flexible whip or a system of whips with novel attachments is suspended in a hopper and is caused to impact against fibrous and irregularly shaped particulates in the hopper to fluidize the particulates and facilitate the flow of the particulates through the hopper. The invention provides for the flow of particulates at a substantially constant mass flow rate and uses a minimum of energy.

  8. Fluidizing device for solid particulates

    DOEpatents

    Diebold, James P.; Scahill, John W.

    1986-01-01

    A flexible whip or a system of whips with novel attachments is suspended in a hopper and is caused to impact against fibrous and irregularly shaped particulates in the hopper to fluidize the particulates and facilitate the flow of the particulates through the hopper. The invention provides for the flow of particulates at a substantially constant mass flow rate and uses a minimum of energy.

  9. Analysis of microsize particulates

    NASA Technical Reports Server (NTRS)

    Blanchard, M. B.; Farlow, N. H.; Ferry, G. V.

    1972-01-01

    Unique methods for analyzing individual particles ranging in size from 0.01 to 1000 micrometers have been developed for investigation of nature of cosmic dust. Methods are applicable to particulate aerosols and contaminants characteristically encountered in studies of air pollution and in experiments designed to abate pollution.

  10. Alumina-based ceramic composite

    DOEpatents

    Alexander, Kathleen B.; Tiegs, Terry N.; Becher, Paul F.; Waters, Shirley B.

    1996-01-01

    An improved ceramic composite comprising oxide ceramic particulates, nonoxide ceramic particulates selected from the group consisting of carbides, borides, nitrides of silicon and transition metals and mixtures thereof, and a ductile binder selected from the group consisting of metallic, intermetallic alloys and mixtures thereof is described. The ceramic composite is made by blending powders of the ceramic particulates and the ductile to form a mixture and consolidating the mixture of under conditions of temperature and pressure sufficient to produce a densified ceramic composite.

  11. [Light absorption by suspended particulate matter in Chagan Lake, Jilin].

    PubMed

    Wang, Yuan-Dong; Liu, Dian-Wei; Song, Kai-Shan; Zhang, Bai; Wang, Zong-Ming; Jiang, Guang-Ji; Tang, Xu-Guang; Lei, Xiao-Chun; Wu, Yan-Qing

    2011-01-01

    Spectral characteristics and the magnitudes of light absorption by suspended particulate matter were determined by spectrophotometry in this optically complex Lake Chagan waters for the purpose of surveying the natural variability of the absorption coefficients to parameterize the bio-optical models for converting satellite or in-situ water reflectance signatures into water quality information. Experiments were carried out on seasonal frozen Lake Chagan, one representative inland case-2 water body in Northeast of China. Particulate absorption properties analyzed using the field data on July 15th and October 12th 2009 were measured using the quantitative filter technique to produce absorption spectra containing several fractions that could be attributed to two main optical active constituents (OACs) phytoplankton pigments and non-algal particulates (mineral sediments, and organic detritus). Results suggested that the suspended particulate matter (SPM) concentration was higher while phytoplankton biomass (chlorophyll-a concentration) was lower in July and that in October. The spectral shape of total suspended particulate matter resembled that of non-algal particulates which contributed greater than phytoplankton in total particulate absorption during both periods. An obvious absorption peak occurring at around 440 nm exhibited an increase in phytoplankton contribution in October. Non-algal particulate absorption at 440 nm (a(NAP) (440)) had better correlation with total suspended particulate matter concentration than that with chlorophyll-a over the two periods. Light absorption by phytoplankton pigments in the Chagan lake region was generally lower than that of non-algal components. Chl. a dominating phytoplankton pigment composition functioned exponentially with its absorption coefficients at 440 and 675 nm specifically, the average values of which in July were 0.146 8 m2 x mg(-1) and 0.050 3 respectively while in October they were 0.153 3 and 0.013 2 m2 x mg(-1

  12. Rigid particulate matter sensor

    SciTech Connect

    Hall, Matthew

    2011-02-22

    A sensor to detect particulate matter. The sensor includes a first rigid tube, a second rigid tube, a detection surface electrode, and a bias surface electrode. The second rigid tube is mounted substantially parallel to the first rigid tube. The detection surface electrode is disposed on an outer surface of the first rigid tube. The detection surface electrode is disposed to face the second rigid tube. The bias surface electrode is disposed on an outer surface of the second rigid tube. The bias surface electrode is disposed to face the detection surface electrode on the first rigid tube. An air gap exists between the detection surface electrode and the bias surface electrode to allow particulate matter within an exhaust stream to flow between the detection and bias surface electrodes.

  13. Regenerable particulate filter

    DOEpatents

    Stuecker, John N.; Cesarano, III, Joseph; Miller, James E.

    2009-05-05

    A method of making a three-dimensional lattice structure, such as a filter used to remove particulates from a gas stream, where the physical lattice structure is designed utilizing software simulation from pre-defined mass transfer and flow characteristics and the designed lattice structure is fabricated using a free-form fabrication manufacturing technique, where the periodic lattice structure is comprised of individual geometric elements.

  14. Effects of high energy radiation on the mechanical properties of epoxy/graphite fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Fornes, R. E.; Gilbert, R. D.; Memory, J. D.

    1987-01-01

    Publications and theses generated on composite research are listed. Surface energy changes of an epoxy based on tetraglycidyl diaminodiphenyl methane (TGDDM)/diaminodiphenyl sulfone (DDS), T-300 graphite fiber and T-300/5208 (graphite fiber/epoxy) composites were investigated after irradiation with 0.5 MeV electrons. Electron spin resonance (ESR) investigations of line shapes and the radical decay behavior were made of an epoxy based on tetraglycidyl diaminodiphenyl methane (TGDDM)/diaminodiphenyl sulfone (DDS), T-300 graphite fiber, and T-300/5208 (graphite fiber/epoxy) composites after irradiation with Co(60) gamma-radiation or 0.5 MeV electrons. The results of the experiments are discussed.

  15. Health effects of atmospheric particulates: a medical geology perspective.

    PubMed

    Duzgoren-Aydin, Nurdan S

    2008-01-01

    In this review, atmospheric particulates as composite airborne earth materials often containing both natural and anthropogenic components were examined in the context of medical geology. Despite a vast number of both experimental and epidemiological studies confirming the direct and indirect links between atmospheric particulates and human health, the exact nature of mechanisms affecting the particulate-induced pathogenesis largely remains unexplored. Future in depth research on these areas would be most successful if potential mechanisms are examined with reference to the physical (e.g., size, shape and surface), chemical, mineralogical and source characteristics of particulate matters. The underlying goal of this review was to present the relevant terminology and processes proposed in the literature to explain the interfaces and interactions between atmospheric particles and human body within the framework of "atmospheric particle cycles." The complexities of the interactions were demonstrated through case studies focusing on particulate matter air pollution and malignant mesothelioma occurrences due to environmental exposure to erionite-a fibrous zeolite mineral. There is an urgent need for a standard protocol or speciation methods applicable to earth-materials to guide and streamline studies on etiology of mineral-induced diseases. This protocol or speciation methods should provide relevant procedures to determine the level and extent of physical, chemical and mineralogical heterogeneity of particulate matters as well as quantitative in-situ particulate characteristics.

  16. Composite Crew Module: Primary Structure

    NASA Technical Reports Server (NTRS)

    Kirsch, Michael T.

    2011-01-01

    In January 2007, the NASA Administrator and Associate Administrator for the Exploration Systems Mission Directorate chartered the NASA Engineering and Safety Center to design, build, and test a full-scale crew module primary structure, using carbon fiber reinforced epoxy based composite materials. The overall goal of the Composite Crew Module project was to develop a team from the NASA family with hands-on experience in composite design, manufacturing, and testing in anticipation of future space exploration systems being made of composite materials. The CCM project was planned to run concurrently with the Orion project's baseline metallic design within the Constellation Program so that features could be compared and discussed without inducing risk to the overall Program. This report discusses the project management aspects of the project including team organization, decision making, independent technical reviews, and cost and schedule management approach.

  17. Lidar measurements of airborne particulate matter

    NASA Astrophysics Data System (ADS)

    Li, Guangkun; Philbrick, C. Russell

    2003-03-01

    Raman lidar techniques have been used in remote sensing to measure the aerosol optical extinction in the lower atmosphere, as well as water vapor, temperature and ozone profiles. Knowledge of aerosol optical properties assumes special importance in the wake of studies strongly correlating airborne particulate matter with adverse health effects. Optical extinction depends upon the concentration, composition, and size distribution of the particulate matter. Optical extinction from lidar returns provide information on particle size and density. The influence of relative humidity upon the growth and size of aerosols, particularly the sulfate aerosols along the northeast US region, has been investigated using a Raman lidar during several field measurement campaigns. A particle size distribution model is being developed and verified based on the experimental results. Optical extinction measurements from lidar in the NARSTO-NE-OPS program in Philadelphia PA, during summer of 1999 and 2001, have been analyzed and compared with other measurements such as PM sampling and particle size measurements.

  18. Higher modulus compositions incorporating particulate rubber

    DOEpatents

    Bauman, Bernard D.; Williams, Mark A.

    1999-01-01

    A plastic article having a number of surfaces with at least one surface being modified by contacting that surface with a reactive gas atmosphere containing F.sub.2, Cl.sub.2, O.sub.2, Ozone, SO.sub.3, oxidative acids, or mixtures thereof, at a temperature and gas partial pressure sufficient to increase the surface energy of the at least one surface being modified to at least 40 dynes/cm at a temperature of 20.degree. C., to enhance bonding of non-slip polymer coatings to the modified surface, to which coatings elastomeric or rigid particles may be admixed for imparting a surface profile and increasing the coefficient of friction between the coated surface and the counter-surface.

  19. Multifunctional Particulate Composites for Structural Applications (PREPRINT)

    DTIC Science & Technology

    2008-05-01

    strain rates were measured, it would most likely be found, as is the case with epoxy, that there is a bilinear dependance of yield stress on strain...variations in experimental measurements. Additional testing at several strain rates is underway to further elucidate the strain rate dependance of yield...MNML-8 6e-4 /s 2500 /s Tr ue S tre ss (M Pa ) Figure 4: Strain rate dependance of yield stress for MNML-2, 3, 5, and 8. Table 2: Mulliken

  20. Seasonal variation in concentration and metallic constituents of atmospheric particulates near the western coast of central Taiwan.

    PubMed

    Fang, Guor-Cheng; Wu, Yuh-Shen; Lee, Wen-Jhy; Chou, Te-Yen; Lin, I-Chen

    2006-06-01

    In addition to determining the concentration and metallic constituents of particulate matter at Taichung Harbor in central Taiwan, this study attempts to characterize the mass, metallic elements, composition and concentrations of total suspended particulates (TSP), fine particles and coarse particles. Statistical approaches, such as the Spearman tests, were also adopted to determine the seasonal variations of concentrations of these pollutants. Experimental results indicate that the mean TSP, fine particulate and coarse particulate concentrations in spring and winter are higher than in summer and autumn on the western coast of central Taiwan. Spearman statistical analysis of metallic elements Mn and Pb showed high concentration coefficients for fine and coarse particulates on the western coast of central Taiwan. The order of mean metallic concentrations in TSP, coarse particulates and fine particles was Fe > Zn > Mg > Cu> Cr > Mn > Pb in TSP, Fe > Cu > Zn > Mg > Mn > Pb > Cr in coarse particulates and Fe > Cu > Mg > Pb > Zn > Mn > Cr in fine particulates.

  1. Apparatus for particulate matter analysis

    DOEpatents

    Gundel, Lara A.; Apte, Michael G.; Hansen, Anthony D.; Black, Douglas R.

    2007-01-30

    The apparatus described herein is a miniaturized system for particle exposure assessment (MSPEA) for the quantitative measurement and qualitative identification of particulate content in gases. The present invention utilizes a quartz crystal microbalance (QCM) or other mass-sensitive temperature compensated acoustic wave resonator for mass measurement. Detectors and probes and light sources are used in combination for the qualitative determination of particulate matter.

  2. Particulate erosion mechanisms

    NASA Technical Reports Server (NTRS)

    Veerabhadrarao, P.; Buckley, D. H.

    1983-01-01

    Particulate damage and erosion of ductile metals are today plaguing design and field engineers in diverse fields of engineering and technology. It was found that too many models and theories were proposed leading to much speculation from debris analysis and failure mechanism postulations. Most theories of solid particle erosion are based on material removal models which do not fully represent the actual physical processes of material removal. The various mechanisms proposed thus far are: melting, low-cycle fatigue, extrusion, delamination, shear localization, adhesive material transfer, etc. The experimental data on different materials highlighting the observed failure modes of the deformation and cutting wear processes using optical and scanning electron microscopy are presented. The most important mechanisms proved from the experimental observations of the specimens exposed to both spherical and angular particles are addressed, and the validity of the earlier theories discussed. Both the initial stages of damage and advanced stages of erosion were studied to gain a fundamental understanding of the process.

  3. Pressure driven particulate flows

    SciTech Connect

    Ingher, M.S.; Mondy, L.A.

    1996-03-01

    Numerical simulations of pressure-driven particulate Stokes flows are performed in cylindrical and rectangular conduits using a parallel boundary element code. Spherical particles are randomly placed in the conduits and a pressure drop between the ends of the conduits is imposed by the boundary conditions to induce a Poiseuille-like flow field. The instantaneous velocities of the particles are then calculated, as well as the additional pressure drop necessary to maintain a constant flow rate. Because the results depend on the spatial distribution of the particles, several random configurations of particles are examined for each case. Depending on two different interpretations of the numerical results, the solid phase can be represented as either leading or lagging the fluid phase. Both of the analyses and interpretations are presented.

  4. Respiratory dose analysis for components of ambient particulate matter

    EPA Science Inventory

    Particulate matter (PM) in the atmosphere is a complex mixture of particles with different sizes and chemical compositions. Although PM is known to induce health effects, specific attributes of PM that may cause health effects are somewhat ambiguous. Dose of each specific compone...

  5. Laboratory Measurements of Particulate Matter Concentrations from Asphalt Pavement Abrasion

    NASA Astrophysics Data System (ADS)

    Fullová, Daša; Đurčanská, Daniela

    2016-12-01

    The issue of emissions from road traffic is compounded by the fact that the number of vehicles and driven kilometres increase each year. Road traffic is one of the main sources of particulate matter and traffic volume is still increasing and has unpleasant impact on longevity of the pavements and the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The contribution deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures of wearing courses are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The contribution offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

  6. FACTORS INFLUENCING THE DEPOSITION OF A COMPOUND THAT PARTITIONS BETWEEN GAS AND PARTICULATE PHASES

    EPA Science Inventory

    How will atmospheric deposition behave for a compound when it reversibly sorbs between gas and atmospheric particulate phases? Two factors influence the answer. What physical mechanisms occur in the sorption process? What are the concentration and composition of atmospheric par...

  7. HIGH VOLUME INJECTION FOR GCMS ANALYSIS OF PARTICULATE ORGANIC SPECIES IN AMBIENT AIR

    EPA Science Inventory

    Detection of organic species in ambient particulate matter typically requires large air sample volumes, frequently achieved by grouping samples into monthly composites. Decreasing the volume of air sample required would allow shorter collection times and more convenient sample c...

  8. Comparison of gene expression profiles induced by coarse, fine, and ultrafile particulate matter

    EPA Science Inventory

    Coarse, fine, and ultrafine particulate matter (PM) fractions possess different physical properties and chemical compositions and may produce different adverse health effects. Studies were undertaken to determine whether or not gene expression patterns may be used to discriminate...

  9. ADVANCED HYBRID PARTICULATE COLLECTOR

    SciTech Connect

    Ye Zhuang; Stanley J. Miller; Michelle R. Olderbak; Rich Gebert

    2001-12-01

    A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the U.S. Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in an entirely novel manner. The AHPC concept combines fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two methods, both in the particulate collection step and in transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and solves the problem of reentrainment and re-collection of dust in conventional baghouses. Phase I of the development effort consisted of design, construction, and testing of a 5.7-m{sup 3}/min (200-acfm) working AHPC model. Results from both 8-hr parametric tests and 100-hr proof-of-concept tests with two different coals demonstrated excellent operability and greater than 99.99% fine-particle collection efficiency. Since all of the developmental goals of Phase I were met, the approach was scaled up in Phase II to a size of 255 m{sup 3}/min (9000 acfm) (equivalent in size to 2.5 MW) and was installed on a slipstream at the Big Stone Power Plant. For Phase II, the AHPC at Big Stone Power Plant was operated continuously from late July 1999 until mid-December 1999. The Phase II results were highly successful in that ultrahigh particle collection efficiency was achieved, pressure drop was well controlled, and system operability was excellent. For Phase III, the AHPC was modified into a more compact configuration, and components were installed that were closer to what would be used in a full-scale commercial design. The modified AHPC was operated from April to July 2000. While operational results were acceptable during this time, inspection of bags in the summer of 2000 revealed some membrane damage to the fabric that appeared to be

  10. Electrically heated particulate filter restart strategy

    DOEpatents

    Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

    2011-07-12

    A control system that controls regeneration of a particulate filter is provided. The system generally includes a propagation module that estimates a propagation status of combustion of particulate matter in the particulate filter. A regeneration module controls current to the particulate filter to re-initiate regeneration based on the propagation status.

  11. Measurement of vehicle particulate emissions.

    PubMed Central

    Beltzer, M

    1975-01-01

    A constant volume sampler (CVS) compatible auto exhaust particulate sampling system has been built which samples exhaust isokinetically at constant temperature. This system yields internally consistent results and is capable of frequent and convenient operation. PMID:50931

  12. Electrical diesel particulate filter (DPF) regeneration

    DOEpatents

    Gonze, Eugene V; Ament, Frank

    2013-12-31

    An exhaust system that processes exhaust generated by an engine includes a diesel particulate filter (DPF) that is disposed downstream of the engine and that filters particulates from the exhaust. An electrical heater is disposed upstream of the DPF and selectively heats the exhaust to initiate combustion of the particulates within the exhaust as it passes therethrough. Heat generated by combustion of the particulates induces combustion of particulates within the DPF.

  13. An Evaluation of the Iosipescu Specimen for Composite Materials Shear Property Measurement. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Ho, Henjen

    1991-01-01

    accuracy of the shear modulus values are made, and the implications for shear strength measurement discussed. Further application of the Iosipescu shear test to woven fabric composites is presented. The limitations of the traditional strain gage instrumentation on the satin weave and high tow plain weave fabrics is discussed. Test results of a epoxy based aluminum particulate composite is also presented. A modification of the Iosipescu specimen is proposed and investigated experimentally and numerically. It is shown that the proposed new specimen design provides a more uniform shear stress field in the test section and greatly reduces the normal and shear stress concentrations in the vicinity of the notches. While the fabrication and the material cost of the proposed specimen is tremendously reduced, it is shown the accuracy of the shear modulus measurement is not sacrificed.

  14. Hydrocarbon-enhanced particulate filter regeneration via microwave ignition

    DOEpatents

    Gonze, Eugene V.; Brown, David B.

    2010-02-02

    A regeneration method for a particulate filter includes estimating a quantity of particulate matter trapped within the particulate filter, comparing the quantity of particulate matter to a predetermined quantity, heating at least a portion of the particulate filter to a combustion temperature of the particulate matter, and introducing hydrocarbon fuel to the particulate filter. The hydrocarbon fuel facilitates combustion of the particulate matter to regenerate the particulate filter.

  15. Composites

    NASA Astrophysics Data System (ADS)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  16. Extraction of dielectric and magnetic properties of carbonyl iron powder composites at high frequencies

    NASA Astrophysics Data System (ADS)

    Zivkovic, I.; Murk, A.

    2012-06-01

    In this paper, we examine carbonyl iron composites in silicone rubber and epoxy matrices. Transmission measurements were performed at W (70 to 110 GHz) and Ka (26 to 40 GHz) bands and effective permittivity and permeability of composites with 10% volume fraction of carbonyl iron powder (CIP) were extracted at these frequencies. To extract permittivity and permeability of carbonyl iron powder in W and Ka bands, we use Looyenga formula. We extract permittivity and permeability of CIP from both silicone rubber and epoxy based composites and good agreement is achieved.

  17. Optical properties of particulate emissions from on-road vehicles

    NASA Astrophysics Data System (ADS)

    Japar, Steven M.; Szkarlat, Ann Cuneo; Gorse, Robert A.

    The light absorbing and light scattering properties of on-road vehicle exhaust particulate were determined as a function of traffic composition at the Allegheny Tunnel on the Pennsylvania Turnpike during August-September 1979. This study was one part of a comprehensive experiment aimed at the chemical and physical characterization of vehicle exhaust particulate. Paniculate light absorption was determined by the integrating plate method, while light scattering was measured with an integrating nephelometer. Mass-specific optical coefficients (at 500.0 nm) have been derived from regressions of the optical and mass emissions data against traffic composition. For diesel vehicles (predominantly heavy-duty, but also including diesel passenger vehicles) the absorption coefficient, b' abs/ M', was found to be 5.13 ± 0.28 m2g-1, while the light scattering coefficient, b' scat/ M', was 1.99 ± 0.07 m2g-1. Diesel vehicle emissions were responsible for greater than 90% of the light extinction in the tunnel, although diesels accounted for only 23% of the vehicle miles travelled. Estimates for b' abs/ M' and b' scat/ M' for particulate from gasoline-powered vehicles were 8 ± 16 m2g-1and 6 ± 10 m2g-1, respectively, while the analogous values for ambient particulate were babs/ M< 1 m2g-1andbscat/ M = 5.0 ± 1.0 m2g-1.

  18. Alumina-based ceramic composite

    DOEpatents

    Alexander, K.B.; Tiegs, T.N.; Becher, P.F.; Waters, S.B.

    1996-07-23

    An improved ceramic composite comprising oxide ceramic particulates, nonoxide ceramic particulates selected from the group consisting of carbides, borides, nitrides of silicon and transition metals and mixtures thereof, and a ductile binder selected from the group consisting of metallic, intermetallic alloys and mixtures thereof is described. The ceramic composite is made by blending powders of the ceramic particulates and the ductile to form a mixture and consolidating the mixture of under conditions of temperature and pressure sufficient to produce a densified ceramic composite. 5 figs.

  19. Alumina-Reinforced Zirconia Composites

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Bansal, Narottam P.

    2003-01-01

    Alumina-reinforced zirconia composites, used as electrolyte materials for solid oxide fuel cells, were fabricated by hot pressing 10 mol percent yttria-stabilized zirconia (10-YSZ) reinforced with two different forms of alumina particulates and platelets each containing 0 to 30 mol percent alumina. Major mechanical and physical properties of both particulate and platelet composites including flexure strength, fracture toughness, slow crack growth, elastic modulus, density, Vickers microhardness, thermal conductivity, and microstructures were determined as a function of alumina content either at 25 C or at both 25 and 1000 C. Flexure strength and fracture toughness at 1000 C were maximized with 30 particulate and 30 mol percent platelet composites, respectively, while resistance to slow crack growth at 1000 C in air was greater for 30 mol percent platelet composite than for 30 mol percent particulate composites.

  20. High strength particulate ceramics

    DOEpatents

    Liles, Kenneth J.; Hoyer, Jesse L.; Mlynarski, Kenneth W.

    1991-01-01

    This invention relates to new and useful hard, dense, composite materials made from metallic nitrides such as titanium nitride when combined with aluminum oxide and aluminum nitride and a process comprising the steps of: (1) mixing constituent materials using kerosene as a mixing medium; (2) screening, settling, filtering, and washing the mixture in acetone; (3) filling and sealing said materials in a latex mold; (4) isostatically pressing the material into a compacted powder; and (5) sintering the compacted powder in a gas atmosphere at 1,850.degree. C. for two hours.

  1. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

  2. Enhanced magnetostrictive effect in epoxy-bonded Tb{sub x}Dy{sub 0.9−x}Nd{sub 0.1}(Fe{sub 0.8}Co{sub 0.2}){sub 1.93} pseudo 1–3 particulate composites

    SciTech Connect

    Liu, J. J. E-mail: liujjimr@gmail.com; Pan, Z. B.; Song, X. H.; Zhang, Z. R.; Ren, W. J.

    2015-05-07

    The spin configuration and spontaneous magnetostriction λ{sub 111} of Tb{sub x}Dy{sub 0.9−x}Nd{sub 0.1}(Fe{sub 0.8}Co{sub 0.2}){sub 1.93} (0.20 ≤ x ≤ 0.60) alloys have been investigated. The easy magnetization direction (EMD) at room temperature was observed towards the 〈111〉 axis when 0.40 ≤ x ≤ 0.60, accompanied by a rhombohedral distortion with large spontaneous magnetostriction coefficients λ{sub 111}, which increases from 1640 ppm for x = 0.40 to 1900 ppm for x = 0.60. The strong 〈111〉-oriented pseudo 1–3 particulate composite was fabricated by embedding and aligning particles in a passive epoxy matrix under an applied magnetic field. An enhanced magnetostrictive effect, the large low-field magnetostriction, λ{sub a}, as high as 480 ppm at 3 kOe, was obtained for the sample of x = 0.40, in an excess of 75% of its polycrystalline alloy although it only contains 27 vol. % alloy particles. This enhanced effect can be attributed to its low magnetic anisotropy, anisotropic magnetostrictive nature (e.g., λ{sub 111} ≠ λ{sub 100,} 〈111〉EMD), chain structure, and the 〈111〉-textured orientation. In addition, we give a direct experimental support that the 〈111〉EMD of particle and the strong 〈111〉-textured orientation are the crucial factors to realize the enhanced magnetostrictive effect in 1–3 particulate composites.

  3. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar (registered trademark)-Fiber-Reinforced Polymer-Matrix Composites

    DTIC Science & Technology

    2013-03-01

    Derivation of the Materials Constitutive Relations for Carbon Nanotube Reinforced Poly-Vinyl-Ester-Epoxy Based Composites, J. Mater. Sci., 2007, 42, p...within the yarns , fiber/matrix de-bonding, diffuse delamination/interlam- ina separation, etc.) as well as discrete damage modes (e.g., transverse...fabric. Specifically, details of yarn weaving and crimping, yarn cross-section change, and yarn sliding at the warp- yarn /weft- yarn cross-over points are

  4. Particulate matter and preterm birth

    EPA Science Inventory

    Particulate matter (PM) has been variably associated with preterm birth (PTB) (gestation <37 weeks), but the role played by specific chemical components of PM has been little studied. We examined the association between ambient PM <2.5 micrometers in aerodynamic diameter (PM2.S) ...

  5. Source Testing for Particulate Matter.

    ERIC Educational Resources Information Center

    DeVorkin, Howard

    Developed for presentation at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971, this outline covers procedures for the testing of particulate matter. These are: (1) basic requirements, (2) information required, (3) collection of samples, (4) processing of samples, (5)…

  6. MODELING PARTICULATE CHARGING IN ESPS

    EPA Science Inventory

    In electrostatic precipitators there is a strong interaction between the particulate space charge and the operating voltage and current of an electrical section. Calculating either the space charge or the operating point when the other is fixed is not difficult, but calculating b...

  7. Amorphous metal composites

    DOEpatents

    Byrne, Martin A.; Lupinski, John H.

    1984-01-01

    An improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite.

  8. Remote monitoring of environmental particulate pollution - A problem in inversion of first-kind integral equations

    NASA Technical Reports Server (NTRS)

    Fymat, A. L.

    1975-01-01

    The determination of the microstructure, chemical nature, and dynamical evolution of scattering particulates in the atmosphere is considered. A description is given of indirect sampling techniques which can circumvent most of the difficulties associated with direct sampling techniques, taking into account methods based on scattering, extinction, and diffraction of an incident light beam. Approaches for reconstructing the particulate size distribution from the direct and the scattered radiation are discussed. A new method is proposed for determining the chemical composition of the particulates and attention is given to the relevance of methods of solution involving first kind Fredholm integral equations.

  9. Particulate emissions from concentrated animal feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concentrated animal feeding operations (CAFOs), including open beef cattle feedlots, swine facilities, and poultry facilities, can emit large amounts of particulate matter, including TSP (total suspended particulates), PM10 (particulate matter with equivalent aerodynamic diameter of 10 mm or less) a...

  10. The movement of small particulate matter in the early solar system and the formation of satellites

    NASA Technical Reports Server (NTRS)

    Gold, T.

    1974-01-01

    The motions of the abundant small particulate matter in the early solar system are discussed. The effects of gas drag and resonance effects of perturbing forces could have led to accretion and differentiation of the matter. The composition of the moon and the existence of the rings of Saturn can be explained on the basis of the assembly of small particulate matter in satellite orbits around the planets.

  11. Mineralogy and geochemistry of atmospheric particulates in western Iran

    NASA Astrophysics Data System (ADS)

    Ahmady-Birgani, Hesam; Mirnejad, Hassan; Feiznia, Sadat; McQueen, Ken G.

    2015-10-01

    This study investigates the mineralogy and physico-chemical properties of atmospheric particulates collected at Abadan (southwestern Iran) near the Persian Gulf coast and Urmia (northwestern Iran) during ambient and dust events over 6 months (winter 2011; spring 2012). Particle sizes collected were: TSP (total suspended particulates); PM10 (particulates <10 μm); and PM2.5 (particulates <2.5 μm). Minerals were identified using X-ray diffraction (XRD); particle morphology and composition were examined by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX). Major minerals detected are calcite, quartz, clay minerals and gypsum, with relative abundance related to sampling site, collection period, wind direction, sampling head, and total sample amount. The anomalously high calcite content appears a characteristic feature originated from calcareous soils of the region. SEM observations indicated a wide range of particle morphologies over the 1-50 μm size range, with spherical, platy, cubic, elongate and prismatic shapes and rounding from angular to rounded. Energy dispersive X-ray analysis of TSP samples from both sites for non-dusty periods indicated that the sampled mineral suite contained Al, Mg, Na, Cl, P, S, Ca, K, Fe, Ti, and Si, mostly reflecting calcite, quartz, aluminosilicates, clays, gypsum and halite. Additionally, As, Pb, Zn, Mn, Sc, Nd, W, Ce, La, Ba and Ni were detected in TSP, PM10 and PM2.5 samples collected during dust events.

  12. Method for preparing ceramic composite

    DOEpatents

    Alexander, K.B.; Tiegs, T.N.; Becher, P.F.; Waters, S.B.

    1996-01-09

    A process is disclosed for preparing ceramic composite comprising blending TiC particulates, Al{sub 2}O{sub 3} particulates and nickel aluminide and consolidating the mixture at a temperature and pressure sufficient to produce a densified ceramic composite having fracture toughness equal to or greater than 7 MPa m{sup 1/2}, a hardness equal to or greater than 18 GPa. 5 figs.

  13. Method for preparing ceramic composite

    DOEpatents

    Alexander, Kathleen B.; Tiegs, Terry N.; Becher, Paul F.; Waters, Shirley B.

    1996-01-01

    A process for preparing ceramic composite comprising blending TiC particulates, Al.sub.2 O.sub.3 particulates and nickle aluminide and consolidating the mixture at a temperature and pressure sufficient to produce a densified ceramic composite having fracture toughness equal to or greater than 7 MPa m.sup.1/2, a hardness equal to or greater than 18 GPa.

  14. Polarization signatures of airborne particulates

    NASA Astrophysics Data System (ADS)

    Raman, Prashant; Fuller, Kirk A.; Gregory, Don A.

    2013-07-01

    Exploratory research has been conducted with the aim of completely determining the polarization signatures of selected particulates as a function of wavelength. This may lead to a better understanding of the interaction between electromagnetic radiation and such materials, perhaps leading to the point detection of bio-aerosols present in the atmosphere. To this end, a polarimeter capable of measuring the complete Mueller matrix of highly scattering samples in transmission and reflection (with good spectral resolution from 300 to 1100 nm) has been developed. The polarization properties of Bacillus subtilis (surrogate for anthrax spore) are compared to ambient particulate matter species such as pollen, dust, and soot. Differentiating features in the polarization signatures of these samples have been identified, thus demonstrating the potential applicability of this technique for the detection of bio-aerosol in the ambient atmosphere.

  15. Material Instabilities in Particulate Systems

    NASA Technical Reports Server (NTRS)

    Goddard, J. D.

    1999-01-01

    Following is a brief summary of a theoretical investigation of material (or constitutive) instability associated with shear induced particle migration in dense particulate suspensions or granular media. It is shown that one can obtain a fairly general linear-stability analysis, including the effects of shear-induced anisotropy in the base flow as well as Reynolds dilatancy. A criterion is presented here for simple shearing instability in the absence of inertia and dilatancy.

  16. Particulate gravity currents on Venus

    NASA Astrophysics Data System (ADS)

    Waltham, Dave; Pickering, Kevin T.; Bray, Veronica J.

    2008-02-01

    Canali are moderately sinuous channels, typically a few kilometers wide and hundreds of kilometers long, that occur principally on the plains of Venus. Plausible hypotheses for their formation include the following: open channels cut by exotic, low-viscosity lavas; roofed-over basaltic lava channels; or water on a cooler, wetter ancient Venus. Although it is accepted that a fluid cut these channels, none of these hypotheses are entirely satisfactory. It is therefore prudent to investigate other explanations. A particulate gravity current is a rapidly moving, sediment-laden flow that moves downslope as a result of its high density compared to the ambient fluid. This high density is produced by suspension of dense particles in a lower-density fluid. As these flows are largely driven by slope, rather than by momentum, they are potentially capable of traveling great distances, producing extensive channel systems. We apply this process to Venus, exploring its channel-forming potential via mathematical modeling and morphological comparison of submarine channels on Earth to canali on Venus. Results of our modeling show that atmospheric particulate gravity currents are physically and geologically plausible on Venus. The potential of this process to form channels of great length is such that particulate gravity currents can be considered as an alternate explanation for canali genesis.

  17. Impact of maritime transport on particulate matter concentrations and chemical compositions in four port-cities of the Adriatic/Ionian area: an overview of the results of POSEIDON project

    NASA Astrophysics Data System (ADS)

    Contini, Daniele; Gambaro, Andrea; Argiriou, Athanasios; Alebic-Juretic, Ana; Barbaro, Elena; Cesari, Daniela; Dimopoulos, Spiros; Dinoi, Adelaide; Donateo, Antonio; Gregoris, Elena; Karagiannidis, Athanasios; Ivosevic, Tatjana; Liora, Natalia; Melas, Dimitrios; Merico, Eva; Mifka, Boris; Orlic, Ivo; Poupkou, Anastasia; Sarovic, Kristina

    2015-04-01

    particle number concentrations (PNC) was larger at all sites (between 6% and 26%). This demonstrates that ship particulate emissions include mainly small and ultrafine particles. The trend of the impact of passenger ships primary emissions to PM2.5 concentrations in Venice between 2007 and 2012 showed a decrease from 7% (±1%) to 3.5% (±1%) even if the gross tonnage of ship traffic increased in the same period by 47% (Contini et al., 2015). This was a consequence of the use of low-sulphur content fuels due to the application of local mitigation strategies and of the European Directive 2005/33/EC. The WRF-CAMx modeling system was applied over the Central and Eastern Mediterranean so as to identify the air quality impact of ship emissions. The zero-out modelling method was implemented involving model simulations performed while including and omitting the ship emissions. The results for both gaseous and particulate pollutant concentrations generally show a fairly good agreement with observations at the areas under study. Agrawal et al., 2009. Environmental Science and Technology 43, 5398-5402. Cesari et al., 2014. Science of the Total Environment 497-498, 392-400. Contini et al., 2015. Atmospheric Environment 102, 183-190. Viana et al., 2014. Atmospheric Environment 90, 96-105.

  18. Zone heated diesel particulate filter electrical connection

    DOEpatents

    Gonze, Eugene V.; Paratore, Jr., Michael J.

    2010-03-30

    An electrical connection system for a particulate filter is provided. The system includes: a particulate filter (PF) disposed within an outer shell wherein the PF is segmented into a plurality of heating zones; an outer mat disposed between the particulate filter and the outer shell; an electrical connector coupled to the outer shell of the PF; and a plurality of printed circuit connections that extend along the outer surface of the PF from the electrical connector to the plurality of heating zones.

  19. Diesel particulate filter with zoned resistive heater

    DOEpatents

    Gonze, Eugene V [Pinckney, MI

    2011-03-08

    A diesel particulate filter assembly comprises a diesel particulate filter (DPF) and a heater assembly. The DPF filters a particulate from exhaust produced by an engine. The heater assembly has a first metallic layer that is applied to the DPF, a resistive layer that is applied to the first metallic layer, and a second metallic layer that is applied to the resistive layer. The second metallic layer is etched to form a plurality of zones.

  20. Electrically heated particulate filter using catalyst striping

    DOEpatents

    Gonze, Eugene V; Paratore, Jr., Michael J; Ament, Frank

    2013-07-16

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating is applied to the PF that increases a temperature of the combustion of the particulates within the PF.

  1. Particulate residue separators for harvesting devices

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, John R.

    2010-06-29

    A particulate residue separator and a method for separating a particulate residue stream may include a plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams which are formed by the harvesting device and which travel, at least in part, along the plenum and in a direction of the second, exhaust end; and a baffle assembly which is located in partially occluding relation relative to the plenum, and which substantially separates the first and second particulate residue air streams.

  2. Methods of separating particulate residue streams

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, J. Richard

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  3. Powder and particulate production of metallic alloys

    NASA Technical Reports Server (NTRS)

    Grant, N. J.

    1982-01-01

    Developments of particulate metallurgy of alloyed materials where the final products is a fully dense body are discussed. Particulates are defined as powders, flakes, foils, silvers, ribbons and strip. Because rapid solidification is an important factor in particulate metallurgy, all of the particulates must have at least one dimension which is very fine, sometimes as fine as 10 to 50 microns, but move typically up to several hundred microns, provided that the dimension permits a minimum solidification rate of at least 100 K/s.

  4. Electrically heated particulate filter embedded heater design

    DOEpatents

    Gonze, Eugene V.; Chapman, Mark R.

    2014-07-01

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine and wherein an upstream surface of the particulate filter includes machined grooves. A grid of electrically resistive material is inserted into the machined grooves of the exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF.

  5. Particulate Emissions from Gas Turbine Engines. Revision.

    DTIC Science & Technology

    1992-02-01

    with ferrocene additive) Particulate mass emissions from a J79-GE-IOB engine A-48 to A-64 Particulate mass emissions from a J52-P-6B engine A-65 to A...J79-CE-8D engine 4-9 1 with ferrocene additive (Summary of Files 34 through 45) 6 Particulate emissions from the ,J/7-G;E8f) engine 4 - 0l with... ferrocene additive (Summary of Files 46 and 47) 7 Particulate emissions from the J79-GE-8D engine 4-1i with ferrocene additive (Summary of Files 34 through

  6. Combustor for fine particulate coal

    DOEpatents

    Carlson, L.W.

    1988-01-26

    A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover. 4 figs.

  7. Combustor for fine particulate coal

    DOEpatents

    Carlson, L.W.

    1988-11-08

    A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover. 4 figs.

  8. Combustor for fine particulate coal

    DOEpatents

    Carlson, Larry W.

    1988-01-01

    A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover.

  9. Effects of thermal cycling on density, elastic modulus, and vibrational damping in an alumina particulate reinforced aluminum metal matrix composite (Al{sub 2}O{sub 3p}/2014 Al)

    SciTech Connect

    Wolfenden, A.; Tang, H.H.; Chawla, K.; Hermel, T.

    1999-07-01

    The effects of thermal cycling on the mechanical and physical properties, namely, the density, dynamic elastic modulus and vibrational damping, were measured for a particular reinforced metal matrix composite (MMC). The material was made by Duralcan. Specimens were exposed to up thermal cycles from room temperature to 300 C. The density of the material was measured by the Archimedes technique. The dynamic Young`s Modulus and vibrational damping of the material were determined by the piezoelectric ultrasonic composite oscillator technique (PUCOT). The results showed that the density and elastic modulus of the material increased only slightly due to the thermal cycling while the damping increased significantly. An increase in dislocation concentration near the particle/matrix interfaces caused by the thermal cycling could account for the measured results.

  10. [Geochemical characteristics and sources of atmospheric particulates in Shanghai during dust storm event].

    PubMed

    Qian, Peng; Zheng, Xiang-min; Zhou, Li-min

    2013-05-01

    Atmospheric particulates were sampled from three sampling sites of Putuo, Minhang and Qingpu Districts in Shanghai between Oct. , 2009 and Oct. , 2010. In addition, particulate samples were also collected from Nantong, Zhengzhou, Xi'an, and Beijing city where dust storm dust transported along during spring. Element compositions of atmospheric particulates were determined by XRF and ICP-MS. The concentrations of major and trace elements in atmospheric particulates from Putuo, Minhang and Qingpu Districts were similar, indicating their common source. The UCC standardization distribution map showed that the major element composition of dust storm samples was similar to that of loess in northwestern China, indicating that the dust storm dust was mainly derived from Western desert and partly from local area. The REE partition patterns of dust storm dusts among different cities along dust transport route were similar to each other, as well as to those of northern loess, which indicates that the dust storm samples may have the same material source as loess, which mainly comes from crust material. However, the REE partition patterns of non-dust storm particulates were different among the studied cities, and different from those of loess, which suggests that the non-dust storm samples may be mixed with non-crust source material, which is different from dust storm dust and loess. The major element composition and REE partition pattern are effective indicators for source tracing of dust storm dust.

  11. Southern Fine Particulate Monitoring Project

    SciTech Connect

    Ashley Williamson

    2003-05-31

    This final project report presents experimental details, results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the October, 2001-September, 2002 study period.The host site for these measurement activities is the North Birmingham PM monitoring station by the Jefferson County Health Department in Birmingham, AL.The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. During the course of the project, measurement intercomparison data were developed for these instruments and several complementary measurements at the site. The report details the instrument set and operating procedures and describes the resulting data. Report subsections present an overview summary of the data, followed by detailed description of the systematic time behavior of PM{sub 2.5} and other specific particulate size fractions. Specific subsections are included for particle size distribution, light scattering, and particle sulfate data. The final subsection addresses application of the measurements to the practical questions of fine PM generation and transport, source attribution, and PM{sub 2.5} management strategies.

  12. PARTICULATE MATTER, OXIDATIVE STRESS AND ...

    EPA Pesticide Factsheets

    Particulate matter (PM), a component of air pollution has been epidemiologically associated with sudden deaths, cardiovascular and respiratory illnesses. The effects are more pronounced in patients with pre-existing conditions such as asthma, diabetes or obstructive pulmonary disorders. Clinical and experimental studies have historically focused on the cardiopulmonary effects of PM. However, since PM particles carry numerous biocontaminants that are capable of triggering free radical production and cytokine release, the possibility that PM may affect organs systems sensitive to oxidative stress must be considered. Four independent studies that summarize the neurochemical and neuropathological changes found in the brains of PM exposed animals are described here. These were recently presented at two 2007 symposia sponsored by the Society of Toxicology (Charlotte, NC) and the International Neurotoxicology Association (Monterey, CA). Particulates are covered with biocontaminants (e.g., endotoxins, mold, pollen) which convey free radical activity that can damage the lipids, nucleic acids, and proteins of target cells on contact and stimulate inflammatory cytokine release. Although, the historical focus of PM toxicity has been cardiopulmonary targets, it is now appreciated that inhaled nano-size (<100 nm) particles quickly exit the lungs and enter the circulation where they distribute to various organ systems (l.e., liver, kidneys, testes, lymph nodes) (Takenaka et aI

  13. Airborne particulate matter in spacecraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  14. Temporal variability of MODIS aerosol optical depth and chemical characterization of airborne particulates in Varanasi, India.

    PubMed

    Murari, Vishnu; Kumar, Manish; Barman, S C; Banerjee, T

    2015-01-01

    Temporal variation of airborne particulate mass concentration was measured in terms of toxic organics, metals and water-soluble ionic components to identify compositional variation of particulates in Varanasi. Information-related fine particulate mass loading and its compositional variation in middle Indo-Gangetic plain were unique and pioneering as no such scientific literature was available. One-year ground monitoring data was further compared to Moderate Resolution Imaging Spectroradiometer (MODIS) Level 3 retrieved aerosol optical depth (AOD) to identify trends in seasonal variation. Observed AOD exhibits spatiotemporal heterogeneity during the entire monitoring period reflecting monsoonal low and summer and winter high. Ground-level particulate mass loading was measured, and annual mean concentration of PM2.5 (100.0 ± 29.6 μg/m(3)) and PM10 (176.1 ± 85.0 μg/m(3)) was found to exceed the annual permissible limit (PM10: 80 %; PM2.5: 84 %) and pose a risk of developing cardiovascular and respiratory diseases. Average PM2.5/PM10 ratio of 0.59 ± 0.18 also indicates contribution of finer particulates to major variability of PM10. Particulate sample was further processed for trace metals, viz. Ca, Fe, Zn, Cu, Pb, Co, Mn, Ni, Cr, Na, K and Cd. Metals originated mostly from soil/earth crust, road dust and re-suspended dust, viz. Ca, Fe, Na and Mg were found to constitute major fractions of particulates (PM2.5: 4.6 %; PM10: 9.7 %). Water-soluble ionic constituents accounted for approximately 27 % (PM10: 26.9 %; PM2.5: 27.5 %) of the particulate mass loading, while sulphate (8.0-9.5 %) was found as most dominant species followed by ammonium (6.0-8.2 %) and nitrate (5.5-7.0 %). The concentration of toxic organics representing both aliphatic and aromatic organics was determined by organic solvent extraction process. Annual mean toxic organic concentration was found to be 27.5 ± 12.3 μg/m(3) (n = 104) which constitutes significant proportion of

  15. In-situ cure monitoring of advanced composite materials

    NASA Astrophysics Data System (ADS)

    Saliba, Tony; Saliba, Susan; Lanzafame, John; Gudeman, Linda

    Automatic process control and optimization depends on the ability to effectively determine the state of the process. In-situ sensors capable of monitoring the physical and chemical changes are therefore essential. The use of an in-situ acoustic ultrasonic sensor to monitor the cure characteristics of Bismaleimides (BMI) based composite materials was investigated. The acoustic attenuation reflects changes in the viscosity of the resin. The effects on the acoustic response curve of laminate thickness, ply orientation as well as the type of BMI were studied. A general correlation relating the acoustic attenuation of a curing BMI composite to the actual viscosity was developed. The results obtained for BMI were compared to those obtained from epoxy based composite materials.

  16. Particulate emissions from diesel engines: correlation between engine technology and emissions

    PubMed Central

    2014-01-01

    In the last 30 years, diesel engines have made rapid progress to increased efficiency, environmental protection and comfort for both light- and heavy-duty applications. The technical developments include all issues from fuel to combustion process to exhaust gas aftertreatment. This paper provides a comprehensive summary of the available literature regarding technical developments and their impact on the reduction of pollutant emission. This includes emission legislation, fuel quality, diesel engine- and exhaust gas aftertreatment technologies, as well as particulate composition, with a focus on the mass-related particulate emission of on-road vehicle applications. Diesel engine technologies representative of real-world on-road applications will be highlighted. Internal engine modifications now make it possible to minimize particulate and nitrogen oxide emissions with nearly no reduction in power. Among these modifications are cooled exhaust gas recirculation, optimized injections systems, adapted charging systems and optimized combustion processes with high turbulence. With introduction and optimization of exhaust gas aftertreatment systems, such as the diesel oxidation catalyst and the diesel particulate trap, as well as NOx-reduction systems, pollutant emissions have been significantly decreased. Today, sulfur poisoning of diesel oxidation catalysts is no longer considered a problem due to the low-sulfur fuel used in Europe. In the future, there will be an increased use of bio-fuels, which generally have a positive impact on the particulate emissions and do not increase the particle number emissions. Since the introduction of the EU emissions legislation, all emission limits have been reduced by over 90%. Further steps can be expected in the future. Retrospectively, the particulate emissions of modern diesel engines with respect to quality and quantity cannot be compared with those of older engines. Internal engine modifications lead to a clear reduction of the

  17. Particulate emissions from diesel engines: correlation between engine technology and emissions.

    PubMed

    Fiebig, Michael; Wiartalla, Andreas; Holderbaum, Bastian; Kiesow, Sebastian

    2014-03-07

    In the last 30 years, diesel engines have made rapid progress to increased efficiency, environmental protection and comfort for both light- and heavy-duty applications. The technical developments include all issues from fuel to combustion process to exhaust gas aftertreatment. This paper provides a comprehensive summary of the available literature regarding technical developments and their impact on the reduction of pollutant emission. This includes emission legislation, fuel quality, diesel engine- and exhaust gas aftertreatment technologies, as well as particulate composition, with a focus on the mass-related particulate emission of on-road vehicle applications. Diesel engine technologies representative of real-world on-road applications will be highlighted.Internal engine modifications now make it possible to minimize particulate and nitrogen oxide emissions with nearly no reduction in power. Among these modifications are cooled exhaust gas recirculation, optimized injections systems, adapted charging systems and optimized combustion processes with high turbulence. With introduction and optimization of exhaust gas aftertreatment systems, such as the diesel oxidation catalyst and the diesel particulate trap, as well as NOx-reduction systems, pollutant emissions have been significantly decreased. Today, sulfur poisoning of diesel oxidation catalysts is no longer considered a problem due to the low-sulfur fuel used in Europe. In the future, there will be an increased use of bio-fuels, which generally have a positive impact on the particulate emissions and do not increase the particle number emissions.Since the introduction of the EU emissions legislation, all emission limits have been reduced by over 90%. Further steps can be expected in the future. Retrospectively, the particulate emissions of modern diesel engines with respect to quality and quantity cannot be compared with those of older engines. Internal engine modifications lead to a clear reduction of the

  18. Factors Controlling Liquid Particulate Matter in Amazonia

    NASA Astrophysics Data System (ADS)

    Bateman, A. P.; Gong, Z.; de Sá, S. S.; Wernis, R. A.; Yee, L.; Isaacman-VanWertz, G. A.; Goldstein, A. H.; Castillo, P.; Sedlacek, A. J., III; Palm, B. B.; Campuzano-Jost, P.; Day, D. A.; Hu, W.; Jimenez, J. L.; Alexander, L.; Manzi, A. O.; Souza, R. A. F. D.; Artaxo, P.; Martin, S. T.

    2015-12-01

    The hygroscopic response of particulate matter (PM) during GoAmazon 2014/5 was investigated through the use of particle rebound (or lack thereof) during impaction. The hygroscopic response was measured online and in real-time using a custom designed impaction apparatus. The impaction apparatus was calibrated with respect to particle viscosity indicating a liquid state (viscosity <102 Pa s) for complete adherence (no particle rebound). By varying the PM water content and observing particle rebound as a function of RH (up to 98%), the hygroscopic response and phase state of the PM under investigation was determined. The hygroscopic response curves were categorized according to the rebound fraction at high RH (80 - 98%) bounded by two extremes. 1) Time periods that resemble pure SOM generated under controlled chamber conditions, where no particle rebound is observed above 80% RH. 2) Time periods that a large fraction (10 - 40%) of particles rebound at RH values >95%, an indication of hydrophobic particles. The role of anthropogenic and biogenic factors in controlling the hygroscopic response of PM in Amazonia is investigated through meteorological conditions and particle chemical composition.

  19. Advanced particulate matter control apparatus and methods

    DOEpatents

    Miller, Stanley J [Grand Forks, ND; Zhuang, Ye [Grand Forks, ND; Almlie, Jay C [East Grand Forks, MN

    2012-01-10

    Apparatus and methods for collection and removal of particulate matter, including fine particulate matter, from a gas stream, comprising a unique combination of high collection efficiency and ultralow pressure drop across the filter. The apparatus and method utilize simultaneous electrostatic precipitation and membrane filtration of a particular pore size, wherein electrostatic collection and filtration occur on the same surface.

  20. Air Quality Criteria for Particulate Matter.

    ERIC Educational Resources Information Center

    National Air Pollution Control Administration (DHEW), Washington, DC.

    To assist states in developing air quality standards, this book offers a review of literature related to atmospheric particulates and the development of criteria for air quality. It not only summarizes the current scientific knowledge of particulate air pollution, but points up the major deficiencies in that knowledge and the need for further…

  1. Chemical tracers of particulate emissions from commercial shipping.

    PubMed

    Viana, Mar; Amato, Fulvio; Alastuey, Andrés; Querol, Xavier; Moreno, Teresa; Dos Santos, Saúl García; Herce, María Dolores; Fernández-Patier, Rosalía

    2009-10-01

    Despite the increase of commercial shipping around the world, data are yet relatively scarce on the contribution of these emissions to ambient air particulates. One of the reasons is the complexity in the detection and estimation of shipping contributions to ambient particulates in harbor and urban environments, given the similarity with tracers of other combustion sources. This study aimed to identify specific tracers of shipping emissions in a Mediterranean city with an important harbor (Melilla, Spain). Results showed that for 24 h PM10 and PM2.5 samples, valid tracers of commercial shipping emissions were ratios of V/Ni = 4-5 and V/EC < 2, whereas V/EC > 8 excluded the influence of shipping emissions. Other ratios (V/ S, La/Ce, Zn/Ni, Pb/Zn, OC/EC) and tracers (Pb, Zn) were also tested but did not correlate with this source. Due to the changing composition of diesel fuels, tracers in the Mediterranean Sea may not be representative in other regions of the world and vice versa. The contribution of shipping emissions to ambient particulate matter (PM) urban background levels was quantified by positive matrix factorization (PMF), resulting in 2% and 4% of mean annual PM10 levels (0.8 microg/m3 primary particles and 1.7 microg/m3 secondary particles, with 20% uncertainty) and 14% of mean annual PM2.5 levels (2.6 microg/m3).

  2. Speciation of The Particulate Organic Matter In Three Remote Areas

    NASA Astrophysics Data System (ADS)

    Masclet, Pierre; Marchand, Nicolas; Jaffrezo, Jean Luc; Besombes, Jean Luc

    Total particulate matter was collected as part of three programs between 1999 and 2001 (EAAS in Finland, ESOMPTE in Marseille/Fos and POVA in french alpine valleys). The speciation of the particulate organic matter (POM) was performed by Gas Chromatography or HPLC coupled with a mass spectrometer. 13 organic families were identified in the 245 samples collected. The presence of some functional groups (- COOH; - OH and - CHO) and the carbon chain length are used in order to identify the sources of the particulate pollutants and the physicochemical behaviour during the long range atmospheric transport of the aerosol. The composition of the POM differs depending on the season (the secondary fraction reaches 27 % in summer and only 6% in winter) and on the remoteness of the sources. Alkanes are always the most abundant compounds. Polycyclic aromatic hydrocarbons, alcohols, esters, carboxylic acids and monoaromatic hydrocarbons are present in significant abundance. Some alkenes, aldehydes, ether oxydes, ketones and halocompounds are also found. Alcohols are more abundant in aerosols collected close to marine sites. Long carbon chain esters are mostly found in aerosols collected in high density vegetation areas and relatively high concentrations of PAH are measured in aerosols collected close to highly populated areas. These three families are good geochemical tracers, respectively of marine, biogenic and anthropic sources.

  3. Electrically heated particulate filter propagation support methods and systems

    DOEpatents

    Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

    2011-06-07

    A control system that controls regeneration of a particulate filter is provided. The system generally includes a regeneration module that controls current to the particulate filter to initiate combustion of particulate matter in the particulate filter. A propagation module estimates a propagation status of the combustion of the particulate matter based on a combustion temperature. A temperature adjustment module controls the combustion temperature by selectively increasing a temperature of exhaust that passes through the particulate filter.

  4. Advanced Fine Particulate Characterization Methods

    SciTech Connect

    Steven Benson; Lingbu Kong; Alexander Azenkeng; Jason Laumb; Robert Jensen; Edwin Olson; Jill MacKenzie; A.M. Rokanuzzaman

    2007-01-31

    The characterization and control of emissions from combustion sources are of significant importance in improving local and regional air quality. Such emissions include fine particulate matter, organic carbon compounds, and NO{sub x} and SO{sub 2} gases, along with mercury and other toxic metals. This project involved four activities including Further Development of Analytical Techniques for PM{sub 10} and PM{sub 2.5} Characterization and Source Apportionment and Management, Organic Carbonaceous Particulate and Metal Speciation for Source Apportionment Studies, Quantum Modeling, and High-Potassium Carbon Production with Biomass-Coal Blending. The key accomplishments included the development of improved automated methods to characterize the inorganic and organic components particulate matter. The methods involved the use of scanning electron microscopy and x-ray microanalysis for the inorganic fraction and a combination of extractive methods combined with near-edge x-ray absorption fine structure to characterize the organic fraction. These methods have direction application for source apportionment studies of PM because they provide detailed inorganic analysis along with total organic and elemental carbon (OC/EC) quantification. Quantum modeling using density functional theory (DFT) calculations was used to further elucidate a recently developed mechanistic model for mercury speciation in coal combustion systems and interactions on activated carbon. Reaction energies, enthalpies, free energies and binding energies of Hg species to the prototype molecules were derived from the data obtained in these calculations. Bimolecular rate constants for the various elementary steps in the mechanism have been estimated using the hard-sphere collision theory approximation, and the results seem to indicate that extremely fast kinetics could be involved in these surface reactions. Activated carbon was produced from a blend of lignite coal from the Center Mine in North Dakota and

  5. Lateral supply and downward export of particulate matter from upper waters to the seafloor in the deep eastern Fram Strait

    NASA Astrophysics Data System (ADS)

    Lalande, Catherine; Nöthig, Eva-Maria; Bauerfeind, Eduard; Hardge, Kristin; Beszczynska-Möller, Agnieszka; Fahl, Kirsten

    2016-08-01

    Time-series sediment traps were deployed at 4 depths in the eastern Fram Strait from July 2007 to June 2008 to investigate variations in the magnitude and composition of the sinking particulate matter from upper waters to the seafloor. Sediment traps were deployed at 196 m in the Atlantic Water layer, at 1296 and 2364 m in the intermediate and deep waters, and at 2430 m on a benthic lander in the near-bottom layer. Fluxes of total particulate matter, particulate organic carbon, particulate organic nitrogen, biogenic matter, lithogenic matter, biogenic particulate silica, calcium carbonate, dominant phytoplankton cells, and zooplankton fecal pellets increased with depth, indicating the importance of lateral advection on fluxes in the deep Fram Strait. The lateral supply of particulate matter was further supported by the constant fluxes of biomarkers such as brassicasterol, alkenones, campesterol, β-sitosterol, and IP25 at all depths sampled. However, enhanced fluxes of diatoms and appendicularian fecal pellets from the upper waters to the seafloor in the presence of ice during spring indicated the rapid export (15-35 days) of locally-produced large particles that likely contributed most of the food supply to the benthic communities. These results show that lateral supply and downward fluxes are both important processes influencing the transport of particulate matter to the seafloor in the deep eastern Fram Strait, and that particulate matter size dictates the prevailing sinking process.

  6. Trace element geochemistry of marine biogenic particulate matter

    SciTech Connect

    Collier, R.W.

    1981-02-01

    Plankton samples were investigated for physical and chemical leaching decomposition to identify the major and trace element composition of particulate carrier phases. The identification of trace element/major element ratios in the biogenic materials was emphasized. The majority of the trace elements in the samples were directly associated with the nonskeletal organic phases of the plankton. Calcium carbonate and opal were not significant carriers for any of the trace elements studied. A refractory phase containing Al and Fe in terrigenous ratios was present in all samples, even from the more remote marine locations.

  7. Sub-micrometre particulate matter is primarily in liquid form over Amazon rainforest

    NASA Astrophysics Data System (ADS)

    Bateman, Adam P.; Gong, Zhaoheng; Liu, Pengfei; Sato, Bruno; Cirino, Glauber; Zhang, Yue; Artaxo, Paulo; Bertram, Allan K.; Manzi, Antonio O.; Rizzo, Luciana V.; Souza, Rodrigo A. F.; Zaveri, Rahul A.; Martin, Scot T.

    2016-01-01

    Atmospheric particulate matter influences the Earth’s energy balance directly, by altering or absorbing solar radiation, and indirectly by influencing cloud formation. Whether organic particulate matter exists in a liquid, semi-solid, or solid state can affect particle growth and reactivity, and hence particle number, size and composition. The properties and abundance of particles, in turn, influence their direct and indirect effects on energy balance. Non-liquid particulate matter was identified over a boreal forest of Northern Europe, but laboratory studies suggest that, at higher relative humidity levels, particles can be liquid. Here we measure the physical state of particulate matter with diameters smaller than 1 μm over the tropical rainforest of central Amazonia in 2013. A real-time particle rebound technique shows that the particulate matter was liquid for relative humidity greater than 80% for temperatures between 296 and 300 K during both the wet and dry seasons. Combining these findings with the distributions of relative humidity and temperature in Amazonia, we conclude that near-surface sub-micrometre particulate matter in Amazonia is liquid most of the time during both the wet and the dry seasons.

  8. Effect of Pigmentation in Particulate Formation from Fluoropolymer Thermodegradation in Microgravity

    NASA Technical Reports Server (NTRS)

    Srivastava, Rajiv; McKinnon, J. Thomas; Todd, Paul

    1998-01-01

    Fires aboard spacecraft have occurred as a result of overheated electrical wires and thermodegradation of their insulation, which is composed of fluoropolymers. The particulate products of polymer thermodegradation are only 20-50 run in diameter and are thought to play a role in "polymer fume fever". Therefore an experimental study of the particulates produced by intense ohmic heating of various fluoropolymer-insulated 20 AWG copper wire (representative of spacecraft materials) was undertaken in normal gravity and in microgravity. The 2.2 s drop facility at NASA LeRC and 1.5 s drop facility at the Colorado School of Mines were used to achieve low gravity conditions. Thermophoretic sampling was used for particulate collection. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) were used to characterize the smoke particulates. It was found that the color of PTFE (Polytetrafluoroethylene) insulation has an overwhelming effect on the size, shape, morphology and, composition of the particulates. Size distributions and shape analyses using computerized image analysis showed that particle size distributions were also dependent on the pigment of the fluoropolymer insulation. The influence of pigment was observed in experiments under both normal and microgravity. Under microgravity conditions, owing to the lack of natural convective transport of particulates, much more particle aggregation was observed, and the nature of the aggregates was dependent on the color of the insulation.

  9. Source apportionment studies on particulate matter in Beijing/China

    NASA Astrophysics Data System (ADS)

    Suppan, P.; Shen, R.; Shao, L.; Schrader, S.; Schäfer, K.; Norra, S.; Vogel, B.; Cen, K.; Wang, Y.

    2013-05-01

    More than 15 million people in the greater area of Beijing are still suffering from severe air pollution levels caused by sources within the city itself but also from external impacts like severe dust storms and long range advection from the southern and central part of China. Within this context particulate matter (PM) is the major air pollutant in the greater area of Beijing (Garland et al., 2009). PM did not serve only as lead substance for air quality levels and therefore for adverse health impact effects but also for a strong influence on the climate system by changing e.g. the radiative balance. Investigations on emission reductions during the Olympic Summer Games in 2008 have caused a strong reduction on coarser particles (PM10) but not on smaller particles (PM2.5). In order to discriminate the composition of the particulate matter levels, the different behavior of coarser and smaller particles investigations on source attribution, particle characteristics and external impacts on the PM levels of the city of Beijing by measurements and modeling are performed: a) Examples of long term measurements of PM2.5 filter sampling in 2010/2011 with the objectives of detailed chemical (source attribution, carbon fraction, organic speciation and inorganic composition) and isotopic analyses as well as toxicological assessment in cooperation with several institutions (Karlsruhe Institute of Technology (IfGG/IMG), Helmholtz Zentrum München (HMGU), University Rostock (UR), Chinese University of Mining and Technology Beijing, CUMTB) will be discussed. b) The impact of dust storm events on the overall pollution level of particulate matter in the greater area of Beijing is being assessed by the online coupled comprehensive model system COSMO-ART. First results of the dust storm modeling in northern China (2011, April 30th) demonstrates very well the general behavior of the meteorological parameters temperature and humidity as well as a good agreement between modeled and

  10. Particulate oxidative burden associated with firework activity.

    PubMed

    Godri, Krystal J; Green, David C; Fuller, Gary W; Dall'Osto, Manuel; Beddows, David C; Kelly, Frank J; Harrison, Roy M; Mudway, Ian S

    2010-11-01

    Firework events are capable of inducing particulate matter (PM) episodes that lead to exceedances of regulatory limit values. As short-term peaks in ambient PM concentration have been associated with negative impacts on respiratory and cardiovascular health, we performed a detailed study of the consequences of firework events in London on ambient air quality and PM composition. These changes were further related to the oxidative activity of daily PM samples by assessing their capacity to drive the oxidation of physiologically important lung antioxidants including ascorbate, glutathione and urate (oxidative potential, OP). Twenty-four hour ambient PM samples were collected at the Marylebone Road sampling site in Central London over a three week period, including two major festivals celebrated with pyrotechnic events: Guy Fawkes Night and Diwali. Pyrotechnic combustion events were characterized by increased gas phase pollutants levels (NO(x) and SO(2)), elevated PM mass concentrations, and trace metal concentrations (specifically Sr, Mg, K, Ba, and Pb). Relationships between NO(x), benzene, and PM(10) were used to apportion firework and traffic source fractions. A positive significant relationship was found between PM oxidative burden and individual trace metals associated with each of these apportioned source fractions. The level of exposure to each source fraction was significantly associated with the total OP. The firework contribution to PM total OP, on a unit mass basis, was greater than that associated with traffic sources: a 1 μg elevation in firework and traffic PM fraction concentration was associated with a 6.5 ± 1.5 OP(T) μg(-1) and 5.2 ± 1.4 OP(T) μg(-1) increase, respectively. In the case of glutathione depletion, firework particulate OP (3.5 ± 0.8 OP(GSH) μg(-1)) considerably exceeded that due to traffic particles (2.2 ± 0.8 OP(GSH) μg(-1)). Therefore, in light of the elevated PM concentrations caused by firework activity and the increased

  11. Toward the next generation of air quality monitoring: Particulate Matter

    NASA Astrophysics Data System (ADS)

    Engel-Cox, Jill; Kim Oanh, Nguyen Thi; van Donkelaar, Aaron; Martin, Randall V.; Zell, Erica

    2013-12-01

    Fine particulate matter is one of the key global pollutants affecting human health. Satellite and ground-based monitoring technologies as well as chemical transport models have advanced significantly in the past 50 years, enabling improved understanding of the sources of fine particles, their chemical composition, and their effect on human and environmental health. The ability of air pollution to travel across country and geographic boundaries makes particulate matter a global problem. However, the variability in monitoring technologies and programs and poor data availability make global comparison difficult. This paper summarizes fine particle monitoring, models that integrate ground-based and satellite-based data, and communications, then recommends steps for policymakers and scientists to take to expand and improve local and global indicators of particulate matter air pollution. One of the key set of recommendations to improving global indicators is to improve data collection by basing particulate matter monitoring design and stakeholder communications on the individual country, its priorities, and its level of development, while at the same time creating global data standards for inter-country comparisons. When there are good national networks that produce consistent quality data that is shared openly, they serve as the foundation for better global understanding through data analysis, modeling, health impact studies, and communication. Additionally, new technologies and systems should be developed to expand personal air quality monitoring and participation of non-specialists in crowd-sourced data collections. Finally, support to the development and improvement of global multi-pollutant indicators of the health and economic effects of air pollution is essential to addressing improvement of air quality around the world.

  12. Radiant zone heated particulate filter

    DOEpatents

    Gonze, Eugene V [Pinckney, MI

    2011-12-27

    A system includes a particulate matter (PM) filter including an upstream end for receiving exhaust gas and a downstream end. A radiant zoned heater includes N zones, where N is an integer greater than one, wherein each of the N zones includes M sub-zones, where M is an integer greater than or equal to one. A control module selectively activates at least a selected one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones, restricts exhaust gas flow in a portion of the PM filter that corresponds to the selected one of the N zones, and deactivates non-selected ones of the N zones.

  13. Methods for Coating Particulate Material

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2013-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  14. Ice particulates in the mesosphere

    NASA Technical Reports Server (NTRS)

    Chesworth, E. T.; Hale, L. C.

    1974-01-01

    The observations of noctilucent clouds, the measurements of hydrated and of large immobile ions, and the light-scattering layer detected by the OGO-6 satellite suggest the presence of particulates, probably ice, in the mesosphere. The correlation between temperature and positive ion conductivity where the vapor pressure over ice becomes greater than atmospheric pressure in the stratopause region indicates the presence of ice crystals throughout the mesosphere over a wide range of latitudes during all seasons. Between one and ten billion ice crystals per cubic meter of order 10 nanometers in diameter can dominate ionization loss processes in the mesosphere, and can explain a variety of experimental observations, including observed solar angle dependence and seasonal variability of electron density.

  15. Time Scales in Particulate Systems

    NASA Astrophysics Data System (ADS)

    Zhang, Duan

    2013-06-01

    While there are many interests of studying interactions of individual particles, macroscopic collective behavior of particles are our main interest in many practical applications. In this talk, I will give a brief overview of the multiscale methods connecting the physics at individual particles to macroscopic quantities and averaged equations. The emphasis will be on dense dissipative particulate systems, such as powders. Unlike conservative particle systems, such as molecular systems, in a dissipative particle system the concept of thermodynamic equilibrium is not very useful unless in very special cases, because the only true thermodynamically equilibrium state in these systems is the state in which nothing moves. Other than idealized simple systems, mesoscale structures are common and important in many practical systems, especially in dissipative systems. Spatial correlations of these mesoscale structures, such as force chains in dense granular system, particle clusters and streamers in fluidized beds have received some recent attentions, partly because they can be visualized. This talk will emphasize the effects of time correlations related to the mesoscale structures. To consider time correlations and history information of the system, I will introduce the mathematical foundation of the Liouville equation, its applicability and limitations. I will derive the generalized Liouville equations for particulate systems with and without interstitial fluids, and then use them to study averaged transport equations and related closures. Interactions among the time scale of particle interactions, the time scale of the mesocale structures, and the time scale of the physical problem as represented by strain rate will be discussed. The effect of these interactions on the closure relations will be illustrated. I will also discuss possible numerical methods of solving the averaged equations, and multiscale numerical algorithms bridging the particle level calculations to

  16. Next Generation Non-particulate Dry Nonwoven Pad for Chemical Warfare Agent Decontamination

    SciTech Connect

    Ramkumar, S S; Love, A; Sata, U R; Koester, C J; Smith, W J; Keating, G A; Hobbs, L; Cox, S B; Lagna, W M; Kendall, R J

    2008-05-01

    New, non-particulate decontamination materials promise to reduce both military and civilian casualties by enabling individuals to decontaminate themselves and their equipment within minutes of exposure to chemical warfare agents or other toxic materials. One of the most promising new materials has been developed using a needlepunching nonwoven process to construct a novel and non-particulate composite fabric of multiple layers, including an inner layer of activated carbon fabric, which is well-suited for the decontamination of both personnel and equipment. This paper describes the development of a composite nonwoven pad and compares efficacy test results for this pad with results from testing other decontamination systems. The efficacy of the dry nonwoven fabric pad was demonstrated specifically for decontamination of the chemical warfare blister agent bis(2-chloroethyl)sulfide (H or sulfur mustard). GC/MS results indicate that the composite fabric was capable of significantly reducing the vapor hazard from mustard liquid absorbed into the nonwoven dry fabric pad. The mustard adsorption efficiency of the nonwoven pad was significantly higher than particulate activated carbon (p=0.041) and was similar to the currently fielded US military M291 kit (p=0.952). The nonwoven pad has several advantages over other materials, especially its non-particulate, yet flexible, construction. This composite fabric was also shown to be chemically compatible with potential toxic and hazardous liquids, which span a range of hydrophilic and hydrophobic chemicals, including a concentrated acid, an organic solvent and a mild oxidant, bleach.

  17. Chemical Characterization of Coarse Particulate Matter in the Desert Southwest - Pinal County Arizona, USA

    EPA Science Inventory

    The Desert Southwest Coarse Particulate Matter Study was undertaken of ambient concentrations and the composition of fine and coarse particles in rural, arid environments. Sampling was conducted in Pinal County, Arizona between February 2009 and February 2010. The goals of this ...

  18. PARTICULATE ORGANIC SOURCE MARKERS IN THE NEW YORK CITY METROPOLITAN AREA

    EPA Science Inventory

    A sampling network of four sites was established for the Speciation of Organics for Apportionment of PM2.5 (SOAP) project during 2002-2003 to investigate composition, seasonal and spatial variability, and source contributions to particulate organic matter in the New York City met...

  19. Diesel particulate emission control without engine modifications

    SciTech Connect

    Filowitz, M.S.; Vataru, M.

    1989-01-01

    This paper describes an ashless, fuel supplement which was found to typically reduce diesel particulate emissions by over 30% while significantly improving fuel economy and power output without any modifications to existing diesel engines or fuels. The treating cost is an order of magnitude less than the estimated cost of reducing aromatic content at the refinery to achieve particulate reductions. The particulate reduction is virtually all from the carbon (soot) fraction. The reduced soot formation translates into less abrasives and less soot-loading stress on the engine oil. Diesel tests conducted are also discussed.

  20. Electrically heated particulate filter enhanced ignition strategy

    SciTech Connect

    Gonze, Eugene V; Paratore, Jr., Michael J

    2012-10-23

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating applied to at least one of the PF and the grid. A control module estimates a temperature of the grid and controls the engine to produce a desired exhaust product to increase the temperature of the grid.

  1. Particulate contamination spectrometer. Volume 1: Technical report

    NASA Technical Reports Server (NTRS)

    Schmitt, R. J.; Boyd, B. A.; Linford, R. M. F.

    1975-01-01

    A laser particulate spectrometer (LPS) system was developed to measure the size and speed distributions of particulate (dusts, aerosols, ice particles, etc.) contaminants. Detection of the particulates was achieved by means of light scattering and extinction effects using a single laser beam to cover a size range of 0.8 to 275 microns diameter and a speed range of 0.2 to 20 meter/second. The LPS system was designed to operate in the high vacuum environment of a space simulation chamber with cold shroud temperatures ranging from 77 to 300 K.

  2. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per...

  3. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per...

  4. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per...

  5. Identifying dominant sources of respirable suspended particulates in Guangzhou, China

    SciTech Connect

    Song, Y.; Dai, W.; Wang, X.S.; Cui, M.M.; Su, H.; Xie, S.D.; Zhang, Y.H.

    2008-09-15

    Respirable suspended particulates (RSP, i.e., particles with an aerodynamic diameter of 10 {mu} m or less) were measured in 2004 and 2005 at seven sites in the rapidly developing Guangzhou area of China. The average RSP concentration was 126 {mu} g m{sup -3}, a high level that could be very harmful to human health. The chemical species composition of the RSP, including organic and elemental carbon, water-soluble ions, and elemental compositions, was also analyzed. The organics and sulfate may be the major components of RSP mass concentrations. Positive matrix factorization (PMF) was used to identify the sources of RSP as secondary sulfates (32%), secondary nitrates (6%), biomass burning (15%), coal fly ash/cement (18%), sea salt (3%), crustal dust (5%), vehicle exhaust (6%), and coal-fired power plants (3%). Reducing coal combustion and controlling vehicle emissions would alleviate RSP pollution, as most of the precursors were components of coal burning emissions and vehicular exhaust.

  6. PARTICULATE MATTER, OXIDATIVE STRESS AND NEUROTOXICITY

    EPA Science Inventory

    Particulate matter (PM), a component of air pollution has been epidemiologically associated with sudden deaths, cardiovascular and respiratory illnesses. The effects are more pronounced in patients with pre-existing conditions such as asthma, diabetes or obstructive pulmonary dis...

  7. Particulate matter, oxidative stress and neurotoxicity.

    EPA Science Inventory

    Particulate matter (PM), a component of air pollution has been epidemiologically associated with sudden deaths, cardiovascular and respiratory illnesses. The effects are more pronounced in patients with pre-existing conditions such as asthma, diabetes or obstructive pulmonary dis...

  8. OPEN PATH OPTICAL SENSING OF PARTICULATE MATTER

    EPA Science Inventory

    The paper discusses the concepts behind recent developments in optical remote sensing (ORS) and the results from experiments. Airborne fugitive and fine particulate matter (PM) from various sources contribute to exceedances of state and federal PM and visibility standards. Recent...

  9. Particulate Matter (Environmental Health Student Portal)

    MedlinePlus

    ... Pollutants Natural Disasters Drinking Water Waterborne Diseases & Illnesses Water Cycle Water Treatment Videos Games Experiments For Teachers Home ... Pollutants Natural Disasters Drinking Water Waterborne Diseases & Illnesses Water Cycle Water Treatment Particulate Matter The Basics We’ve ...

  10. MTCI acoustic agglomeration particulate control

    SciTech Connect

    Chandran, R.R.; Mansour, M.N.; Scaroni, A.W.; Koopmann, G.H.; Loth, J.L.

    1994-10-01

    The overall objective of this project is to demonstrate pulse combination induced acoustic enhancement of coal ash agglomeration and sulfur capture at conditions typical of direct coal-fired turbines and PFBC hot gas cleanup. MTCI has developed an advanced compact pulse combustor island for direct coal-firing in combustion gas turbines. This combustor island comprises a coal-fired pulse combustor, a combined ash agglomeration and sulfur capture chamber (CAASCC), and a hot cyclone. In the MTCI proprietary approach, the pulse combustion-induced high intensity sound waves improve sulfur capture efficiency and ash agglomeration. The resulting agglomerates allow the use of commercial cyclones and achieve very high particulate collection efficiency. In the MTCI proprietary approach, sorbent particles are injected into a gas stream subjected to an intense acoustic field. The acoustic field serves to improve sulfur capture efficiency by enhancing both gas film and intra-particle mass transfer rates. In addition, the sorbent particles act as dynamic filter foci, providing a high density of stagnant agglomerating centers for trapping the finer entrained (in the oscillating flow field) fly ash fractions. A team has been formed with MTCI as the prime contractor and Penn State University and West Virginia University as subcontractors to MTCI. MTCI is focusing on hardware development and system demonstration, PSU is investigating and modeling acoustic agglomeration and sulfur capture, and WVU is studying aerovalve fluid dynamics. Results are presented from all three studies.

  11. The Particulate Air Pollution Controversy

    PubMed Central

    Phalen, Robert F.

    2004-01-01

    Scientists, regulators, legislators, and segments of industry and the lay public are attempting to understand and respond to epidemiology findings of associations between measures of modern particulate air pollutants (PM) and adverse health outcomes in urban dwellers. The associations have been interpreted to imply that tens of thousands of Americans are killed annually by small daily increments in PM. These epidemiology studies and their interpretations have been challenged, although it is accepted that high concentrations of air pollutants have claimed many lives in the past. Although reproducible and statistically significant, the relative risks associated with modern PM are very small and confounded by many factors. Neither toxicology studies nor human clinical investigations have identified the components and/or characteristics of PM that might be causing the health-effect associations. Currently, a massive worldwide research effort is under way in an attempt to identify whom might be harmed and by what substances and mechanisms. Finding the answers is important, because control measures have the potential not only to be costly but also to limit the availability of goods and services that are important to public health. PMID:19330148

  12. SOUTHERN FINE PARTICULATE MONITORING PROJECT

    SciTech Connect

    Unknown

    2002-04-01

    This quarterly report presents results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the January-March, 2002 study period. The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. Some instrumental issues were noted with the upgrade of the APS model 3320 are described in the report, as well as preliminary performance indications for the upgraded instrument. During the quarter preliminary data analysis and modeling studies were conducted to test the potential of the North Birmingham site data for source attribution analyses. Our initial assessment has continued to be optimistic in this regard due to the location of the site relative to several important classes of local and midrange emission sources. We anticipate that these analyses will provide good separations of the effects of major source classes and spatial source clusters, and will provide useful information relevant to PM{sub 2.5} implementation strategies.

  13. New ESP additive controls particulates

    SciTech Connect

    Durham, M.D.; Baldrey, K.E.; Bustard, C.J.; Martin, C.E.; Dharmarajan, N.N.

    1997-06-01

    This article reports that a conditioning agent enhanced precipitator performance after plant switched to low-sulfur coal. Firing low-sulfur coal at a power plant designed for medium- or high-sulfur coal will impact the downstream particulate control device. Since the performance of an electro-static precipitator (ESP) is a strong function of the sulfur content in the coal, switching to a low-sulfur coal will severely impact collection efficiency. Particle resistivity is the dominant parameter affecting the performance of an ESP. When the resistivity is too high, the ESP must be increased in size by a factor of two to three, resulting in proportionally increased capital and operating costs. Fly ash from low-sulfur coal is known to have a typical resistivity one or two orders of magnitude above that for ideal collection efficiency in a well-designed ESP. Therefore, when a utility burning a medium- or high-sulfur coal switches to a low-sulfur coal, the increase in particle resistivity resulting from the reduced SO{sub 3} concentration will lead to severe problems in the ESP. There have been many instances where utilities have switched from a high- to a low-sulfur coal, and the problems caused by the increased resistivity have had such a devastating effect on the performance of the ESP that emissions have increased by a factor of 10.

  14. Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

    NASA Astrophysics Data System (ADS)

    Kaiser, David; Unger, Daniela; Qiu, Guanglong

    2014-07-01

    Estuarine particle fluxes are an integral part of land-ocean-connectivity and influence coastal environmental conditions. In areas with strong anthropogenic impact they may contribute to coastal eutrophication. To investigate the particulate biogeochemistry of a human affected estuary, we sampled suspended, sedimentary and plant particulate matter along the land-ocean continuum from Nanliu River to Lianzhou Bay in southern China. Riverine particle fluxes exceed inputs from land based pond aquaculture. Elemental (C/N) and isotopic composition of particulate organic carbon (δ13C) and total nitrogen (δ15N) showed that suspended and sedimentary organic matter (OM) mainly derive from freshwater and marine phytoplankton, with minor contributions from terrestrial and aquaculture derived particles. Amino acid composition indicates subseasonal variability of production and freshness of phytoplankton OM. Strongest compositional changes of suspended particles are associated with storm-related extreme precipitation events, which introduce soil derived OM. High concentrations of chlorophyll a reflect eutrophic conditions in riverine and coastal waters. Human impact results in high δ15N signals in suspended, sedimentary and plant particulate matter. Using these in a comparison with two little affected sites shows that anthropogenic influence disperses from the Nanliu River to remote estuaries and mangrove areas. Our results suggest that autochthonous production binds anthropogenic nutrients in particles that are transported along the coast.

  15. Particulate matter in the Venus atmosphere

    NASA Technical Reports Server (NTRS)

    Ragent, B.; Esposito, L. W.; Tomasko, M. G.; Marov, M. IA.; Shari, V. P.

    1985-01-01

    The paper presents a summary of the data currently available (June 1984) describing the planet-enshrouding particulate matter in the Venus atmosphere. A description and discussion of the state of knowledge of the Venus clouds and hazes precedes the tables and plots. The tabular material includes a precis of upper haze and cloud-top properties, parameters for model-size distributions for particles and particulate layers, and columnar masses and mass loadings.

  16. Instrumental neutron activation analysis data for cloud-water particulate samples, Mount Bamboo, Taiwan

    USGS Publications Warehouse

    Lin, Neng-Huei; Sheu, Guey-Rong; Wetherbee, Gregory A.; Debey, Timothy M.

    2013-01-01

    Cloud water was sampled on Mount Bamboo in northern Taiwan during March 22-24, 2002. Cloud-water samples were filtered using 0.45-micron filters to remove particulate material from the water samples. Filtered particulates were analyzed by instrumental neutron activation analysis (INAA) at the U.S. Geological Survey National Reactor Facility in Denver, Colorado, in February 2012. INAA elemental composition data for the particulate materials are presented. These data complement analyses of the aqueous portion of the cloud-water samples, which were performed earlier by the Department of Atmospheric Sciences, National Central University, Taiwan. The data are intended for evaluation of atmospheric transport processes and air-pollution sources in Southeast Asia.

  17. Watershed storage and riverine particulate organic radiocarbon

    NASA Astrophysics Data System (ADS)

    Blair, N. E.; Leithold, E. L.

    2011-12-01

    Lateral movement of carbon and other materials across landscapes is punctuated with periods of storage and reaction. Though we understand basic principles concerning transport and storage effects on the nature of some materials, an adequate understanding is lacking of the cumulative impacts of those processes as material migrates across the biogeochemical landscape. This is essential to the interpretation of geochemical soil and sedimentary records of the past as well as to predicting future responses of systems to perturbations in climate or landuse. Sources of organic carbon exported from watersheds can be broadly defined as those recently derived for extant ecosystems, those derived from materials aged and altered in storage (aged soil OC), and fossil material associated with sedimentary bedrock. Separately, these materials are easy to recognize based on isotopic and molecular compositions and each could in principle be linked to specific mass transport processes such as sheet wash, shallow landsliding or gullying. The blending and alteration of original source signatures during storage appear to attenuate the variability of the exported signal within a system and complicate source identification. Riverine particulate organic carbon 14C-compositions reveal robust relationships between radiocarbon content, suspended load concentrations and % organic C. These are explained as a result of mixing of the 14C-free fossil C from sedimentary rocks with 14C-containing material derived from extant ecosystems and soils. In essence, the 14C-content of riverine POC inversely correlates with the muddiness of the system. Whereas one might predict that POC radiocarbon content might decrease with increased storage or residence time in watersheds, no obvious relationship exists between bulk 14C-content observations and watershed size. Instead, the hypothetical watershed size effect is obscured by precipitation- and discharge-driven variations in the mixture of the fossil and non

  18. Inorganic particulates associated with pulmonary alveolar proteinosis: SEM and X-ray microanalysis results.

    PubMed

    Abraham, J L; McEuen, D D

    1986-01-01

    Twenty-four cases of pulmonary alveolar proteinosis (PAP) were studied by light microscopy (LM) and scanning electron microscopy (SEM) to test the hypothesis that PAP was related to silica exposure. Increased numbers of birefringent particles (vs. controls) were found in 78% of PAP cases. SEM was used to locate inorganic particulates in situ, which were individually analyzed using energy dispersive X-ray analysis. When analyzed as an aggregate group of cases, no specific inorganic particulate was evidently associated with the PAP reaction. However, analysis of individual cases revealed more specific associations. The concentration of particles determined by SEM exceeded that found by LM by a factor ranging from 2.7 to 964. The concentration of inorganic particulates per cm3 in the areas of PAP ranged from 1.3 X 10(7) to 1.02 X 10(9). Controls all had less than 10(7) particles per cm3. Available environmental history correlated well with particulate analysis results, e.g., silica in a sandblaster, metal fumes in a welder, and cement particles in a cement finisher. Particulates with unique composition were also found in cases with unavailable histories, e.g. metal fumes suggestive of welding or soldering exposure, silicates suggestive of fine particle exposure (greater than 50% of particles less than 1 micron). Only 1 case (the sandblaster) showed greater than 50% of the particles to be silica. Of the 5 infants with PAP, 3 showed the major particulate to be talc, and 1 had evidence of toxic cadmium selenide fume exposure. These results are consistent with the hypothesis that PAP, at least in the majority of cases, is associated with exposure to small inorganic particulates of several types.

  19. Particulate emissions from construction activities.

    PubMed

    Muleski, Gregory E; Cowherd, Chatten; Kinsey, John S

    2005-06-01

    Although it has long been recognized that road and building construction activity constitutes an important source of particulate matter (PM) emissions throughout the United States, until recently only limited research has been directed to its characterization. This paper presents the results of PM10 and PM2.5 (particles < or = 10 microm and < or = 2.5 microm in aerodynamic diameter, respectively) emission factor development from the onsite testing of component operations at actual construction sites during the period 1998-2001. Much of the testing effort was directed at earthmoving operations with scrapers, because earthmoving is the most important contributor of PM emissions across the construction industry. Other sources tested were truck loading and dumping of crushed rock and mud and dirt carryout from construction site access points onto adjacent public paved roads. Also tested were the effects of watering for control of scraper travel routes and the use of paved and graveled aprons at construction site access points for reducing mud and dirt carryout. The PM10 emissions from earthmoving were found to be up to an order of magnitude greater than predicted by AP-42 emission factors drawn from other industries. As expected, the observed PM2.5:PM10 emission factor ratios reflected the relative importance of the vehicle exhaust and the resuspended dust components of each type of construction activity. An unexpected finding was that PM2.5 emissions from mud and dirt carryout were much less than anticipated. Finally, the control efficiency of watering of scraper travel routes was found to closely follow a bilinear moisture model.

  20. Particulate matter and manganese exposures in Toronto, Canada

    NASA Astrophysics Data System (ADS)

    Pellizzari, E. D.; Clayton, C. A.; Rodes, C. E.; Mason, R. E.; Piper, L. L.; Fort, B.; Pfeifer, G.; Lynam, D.

    was 8.0 ng m -3, compared with 4.7 and 8.6 ng m -3, respectively, for the indoor and outdoor distributions. The highest correlations occurred for personal vs indoor data (0.56) and for outdoor vs roof site data (0.66), and vs fixed site data (0.56). The concentration of Mn in particulate matter, expressed in ppm (w/w), revealed that the fixed site was the highest, followed by the roof site, outdoor, indoor, and personal. The personal and indoor data showed a statistically significant correlation (0.68) while all other correlations between personal or indoor data and outdoor or fixed-site data were quite small. The low correlations of personal and indoor levels with outdoor levels suggest that different sources in the indoor and outdoor microenvironments produce particle matter with dissimilar composition. The correlation results indicate that neither the roof- nor fixed-site concentrations can adequately predict personal particulate matter or Mn exposures.

  1. Nano-composite stainless steel

    DOEpatents

    Dehoff, Ryan R.; Blue, Craig A.; Peter, William H.; Chen, Wei; Aprigliano, Louis F.

    2015-07-14

    A composite stainless steel composition is composed essentially of, in terms of wt. % ranges: 25 to 28 Cr; 11 to 13 Ni; 7 to 8 W; 3.5 to 4 Mo; 3 to 3.5 B; 2 to 2.5 Mn; 1 to 1.5 Si; 0.3 to 1.7 C; up to 2 O; balance Fe. The composition has an austenitic matrix phase and a particulate, crystalline dispersed phase.

  2. Evaluation of the efficiency of extraction of PAHs from diesel particulate matter with pressurized solvents.

    PubMed

    Turrio-Baldassarri, Luigi; Battistelli, Chiara Laura; Iamiceli, Anna Laura

    2003-02-01

    Pressurized Fluid Extraction (PFE) was evaluated for the extraction of polycyclic aromatic hydrocarbons (PAHs) and nitro-derivatives from diesel particulate matter. Extraction conditions were set up by performing several tests in which temperature, solvent strength, pressure, and static time were gradually increased. The results obtained on a laboratory test material made of a "lean" (low content of soluble fraction) Diesel particulate matter indicate that very severe conditions were needed in order to obtain better recoveries of the higher molecular weight molecules. Moreover, extraction efficiency seems to be influenced by the amount of soluble matter in the particulate, so that a "lean" particulate appears more difficult to extract. Recoveries of the deuterated standards of certain PAHs (i.e. indeno[1,2,3- cd]pyrene) were incomplete even with the toughest conditions tested. Experiments carried out on a certified material (SRM 1650 from NIST) also indicate that PFE can perform a better extraction of some of the PAHs than the method used for certification, but still incomplete. Comparison of results obtained on the SRM with different extraction techniques suggests that the composition of the extract varies considerably with the extraction technique and conditions. It is relevant to notice that recent Diesel engines produce leaner particulate: for future materials more drastic extraction conditions will be required.

  3. Iron persistence in a distal hydrothermal plume supported by dissolved-particulate exchange

    NASA Astrophysics Data System (ADS)

    Fitzsimmons, Jessica N.; John, Seth G.; Marsay, Christopher M.; Hoffman, Colleen L.; Nicholas, Sarah L.; Toner, Brandy M.; German, Christopher R.; Sherrell, Robert M.

    2017-02-01

    Hydrothermally sourced dissolved metals have been recorded in all ocean basins. In the oceans' largest known hydrothermal plume, extending westwards across the Pacific from the Southern East Pacific Rise, dissolved iron and manganese were shown by the GEOTRACES program to be transported halfway across the Pacific. Here, we report that particulate iron and manganese in the same plume also exceed background concentrations, even 4,000 km from the vent source. Both dissolved and particulate iron deepen by more than 350 m relative to 3He--a non-reactive tracer of hydrothermal input--crossing isopycnals. Manganese shows no similar descent. Individual plume particle analyses indicate that particulate iron occurs within low-density organic matrices, consistent with its slow sinking rate of 5-10 m yr-1. Chemical speciation and isotopic composition analyses reveal that particulate iron consists of Fe(III) oxyhydroxides, whereas dissolved iron consists of nanoparticulate Fe(III) oxyhydroxides and an organically complexed iron phase. The descent of plume-dissolved iron is best explained by reversible exchange onto slowly sinking particles, probably mediated by organic compounds binding iron. We suggest that in ocean regimes with high particulate iron loadings, dissolved iron fluxes may depend on the balance between stabilization in the dissolved phase and the reversibility of exchange onto sinking particles.

  4. Small-angle light scattering by airborne particulates: Environnement S.A. continuous particulate monitor

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Thaury, Claire; Mineau, Jean-Luc; Gaubicher, Bertrand

    2010-08-01

    Airborne particulate matter may have an effect on human health. It is therefore necessary to determine and control in real time the evolution of the concentration and mass of particulates in the ambient air. These parameters can be obtained using optical methods. We propose here a new instrument, 'CPM' (continuous particulate monitor), for the measurement of light scattered by ambient particulates at small angles. This geometry allows simultaneous and separate detections of PM10, PM2.5 and PM1 fractions of airborne particulate matter, with no influence of their chemical nature and without using theoretical calculations. The ambient air is collected through a standard sampling head (PM10 inlet according to EN 12341, PM2.5 inlet according to EN 14907; or PM1, TSP inlets, standard US EPA inlets). The analysis of the first measurements demonstrates that this new instrument can detect, for each of the seven defined size ranges, real-time variations of particulate content in the ambient air. The measured concentrations (expressed in number per liter) can be converted into total mass concentrations (expressed in micrograms per cubic meter) of all fractions of airborne particulate matters sampled by the system. Periodic comparison with a beta-attenuation mass monitor (MP101M Beta Gauge Analyzer from Environnement S.A. company) allows the calculation of a calibration factor as a function of the mean particulate density that is used for this conversion. It is then possible to provide real-time relative variations of aerosol mass concentration.

  5. Advanced Hybrid Particulate Collector Project Management Plan

    SciTech Connect

    Miller, S.J.

    1995-11-01

    As the consumption of energy increases, its impact on ambient air quality has become a significant concern. Recent studies indicate that fine particles from coal combustion cause health problems as well as atmospheric visibility impairment. These problems are further compounded by the concentration of hazardous trace elements such as mercury, cadmium, selenium, and arsenic in fine particles. Therefore, a current need exists to develop superior, but economical, methods to control emissions of fine particles. Since most of the toxic metals present in coal will be in particulate form, a high level of fine- particle collection appears to be the best method of overall air toxics control. However, over 50% of mercury and a portion of selenium emissions are in vapor form and cannot be collected in particulate control devices. Therefore, this project will focus on developing technology not only to provide ultrahigh collection efficiency of particulate air toxic emissions, but also to capture vapor- phase trace metals such as mercury and selenium. Currently, the primary state-of-the-art technologies for particulate control are fabric filters (baghouses) and electrostatic precipitators (ESPs). However, they both have limitations that prevent them from achieving ultrahigh collection of fine particulate matter and vapor-phase trace metals. The objective of this project is to develop a highly reliable advanced hybrid particulate collector (AHPC) that can provide > 99.99 % particulate collection efficiency for all particle sizes between 0.01 and 50 14m, is applicable for use with all U.S. coals, and is cost-0443competitive with existing technologies. Phase I of the project is organized into three tasks: Task I - Project Management, Reporting, and Subcontract Consulting Task 2 - Modeling, Design, and Construction of 200-acfm AHPC Model Task 3 - Experimental Testing and Subcontract Consulting

  6. Particulate organic carbon and nitrogen export from major Arctic rivers

    NASA Astrophysics Data System (ADS)

    McClelland, J. W.; Holmes, R. M.; Peterson, B. J.; Raymond, P. A.; Striegl, R. G.; Zhulidov, A. V.; Zimov, S. A.; Zimov, N.; Tank, S. E.; Spencer, R. G. M.; Staples, R.; Gurtovaya, T. Y.; Griffin, C. G.

    2016-05-01

    Northern rivers connect a land area of approximately 20.5 million km2 to the Arctic Ocean and surrounding seas. These rivers account for ~10% of global river discharge and transport massive quantities of dissolved and particulate materials that reflect watershed sources and impact biogeochemical cycling in the ocean. In this paper, multiyear data sets from a coordinated sampling program are used to characterize particulate organic carbon (POC) and particulate nitrogen (PN) export from the six largest rivers within the pan-Arctic watershed (Yenisey, Lena, Ob', Mackenzie, Yukon, Kolyma). Together, these rivers export an average of 3055 × 109 g of POC and 368 × 109 g of PN each year. Scaled up to the pan-Arctic watershed as a whole, fluvial export estimates increase to 5767 × 109 g and 695 × 109 g of POC and PN per year, respectively. POC export is substantially lower than dissolved organic carbon export by these rivers, whereas PN export is roughly equal to dissolved nitrogen export. Seasonal patterns in concentrations and source/composition indicators (C:N, δ13C, Δ14C, δ15N) are broadly similar among rivers, but distinct regional differences are also evident. For example, average radiocarbon ages of POC range from ~2000 (Ob') to ~5500 (Mackenzie) years before present. Rapid changes within the Arctic system as a consequence of global warming make it challenging to establish a contemporary baseline of fluvial export, but the results presented in this paper capture variability and quantify average conditions for nearly a decade at the beginning of the 21st century.

  7. Organic speciation of size-segregated atmospheric particulate matter

    NASA Astrophysics Data System (ADS)

    Tremblay, Raphael

    Particle size and composition are key factors controlling the impacts of particulate matter (PM) on human health and the environment. A comprehensive method to characterize size-segregated PM organic content was developed, and evaluated during two field campaigns. Size-segregated particles were collected using a cascade impactor (Micro-Orifice Uniform Deposit Impactor) and a PM2.5 large volume sampler. A series of alkanes and polycyclic aromatic hydrocarbons (PAHs) were solvent extracted and quantified using a gas chromatograph coupled with a mass spectrometer (GC/MS). Large volume injections were performed using a programmable temperature vaporization (PTV) inlet to lower detection limits. The developed analysis method was evaluated during the 2001 and 2002 Intercomparison Exercise Program on Organic Contaminants in PM2.5 Air Particulate Matter led by the US National Institute of Standards and Technology (NIST). Ambient samples were collected in May 2002 as part of the Tampa Bay Regional Atmospheric Chemistry Experiment (BRACE) in Florida, USA and in July and August 2004 as part of the New England Air Quality Study - Intercontinental Transport and Chemical Transformation (NEAQS - ITCT) in New Hampshire, USA. Morphology of the collected particles was studied using scanning electron microscopy (SEM). Smaller particles (one micrometer or less) appeared to consist of solid cores surrounded by a liquid layer which is consistent with combustion particles and also possibly with particles formed and/or coated by secondary material like sulfate, nitrate and secondary organic aerosols. Source apportionment studies demonstrated the importance of stationary sources on the organic particulate matter observed at these two rural sites. Coal burning and biomass burning were found to be responsible for a large part of the observed PAHs during the field campaigns. Most of the measured PAHs were concentrated in particles smaller than one micrometer and linked to combustion sources

  8. Constitutive Characterization of Multi-Constituent Particulate Composites

    DTIC Science & Technology

    2010-10-01

    1971. 97(EM4): p. 1159-1172. 6. Goyanes, S., et al., Yield and internal stresses in aluminum filled epoxy resin. A compression test and positron ... annihilation analysis. Polymer, 2003. 44(11): p. 3193-3199. 7. Kawaguchi, T. and R.A. Pearson, The effect of particle-matrix adhesion on the mechanical

  9. Elemental composition and size distribution of particulates in Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    King, R. B.; Fordyce, J. S.; Neustadter, H. E.; Leibecki, H. F.

    1975-01-01

    Measurements were made of the elemental particle size distribution at five contrasting urban environments with different source-type distributions in Cleveland, Ohio. Air quality conditions ranged from normal to air pollution alert levels. A parallel network of high-volume cascade impactors (5-state) were used for simultaneous sampling on glass fiber surfaces for mass determinations and on Whatman-41 surfaces for elemental analysis by neutron activation for 25 elements. The elemental data are assessed in terms of distribution functions and interrelationships and are compared between locations as a function of resultant wind direction in an attempt to relate the findings to sources.

  10. Relating hygroscopicity and composition of organic aerosol particulate matter

    SciTech Connect

    Duplissy, J.; DeCarlo, P. F.; Dommen, J.; Alfarra, M. R.; Metzger, A.; Barmpadimos, I.; Prevot, A. S. H.; Weingartner, E.; Tritscher, T.; Gysel, M.; Aiken, A. C.; Jimenez, J. L.; Canagaratna, M. R.; Worsnop, D. R.; Collins, D. R.; Tomlinson, J.; Baltensperger, U.

    2011-01-01

    A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "κorg" parameter, and f44 was determined and is given by κorg = 2.2 × f44 - 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. Finally, the use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass.

  11. Structure analysis and size distribution of particulate matter from candles and kerosene combustion in burning chamber

    NASA Astrophysics Data System (ADS)

    Baitimirova, M.; Osite, A.; Katkevics, J.; Viksna, A.

    2012-08-01

    Burning of candles generates particulate matter of fine dimensions that produces poor indoor air quality, so it may cause harmful impact on human health. In this study solid aerosol particles of burning of candles of different composition and kerosene combustion were collected in a closed laboratory system. Present work describes particulate matter collection for structure analysis and the relationship between source and size distribution of particulate matter. The formation mechanism of particulate matter and their tendency to agglomerate also are described. Particles obtained from kerosene combustion have normal size distribution. Whereas, particles generated from the burning of stearin candles have distribution shifted towards finer particle size range. If an additive of stearin to paraffin candle is used, particle size distribution is also observed in range of towards finer particles. A tendency to form agglomerates in a short time is observed in case of particles obtained from kerosene combustion, while in case of particles obtained from burning of candles of different composition such a tendency is not observed. Particles from candles and kerosene combustion are Aitken and accumulation mode particles

  12. Particulate organic matter predicts bacterial productivity in a river dominated estuary

    NASA Astrophysics Data System (ADS)

    Crump, B. C.

    2015-12-01

    Estuaries act as coastal filters for organic and inorganic fluvial materials in which microbial, biogeochemical, and ecological processes combine to transform organic matter and nutrients prior to export to the coastal ocean. The function of this estuarine 'bioreactor' is linked to the residence times of those materials and to rates of microbial heterotrophic activity. Our ability to forecast the impact of global change on estuarine bioreactor function requires an understanding of the basic controls on microbial community activity and diversity. In the Columbia River estuary, the microbial community undergoes a dramatic seasonal shift in species composition during which a spring bacterioplankton community, dominated by Flavobacteriaceae and Oceanospirillales, is replaced by a summer community, dominated by Rhodobacteraceae and several common marine taxa. This annual shift occurs in July, following the spring freshet, when river flow and river chlorophyll concentration decrease and when estuarine water residence time increases. Analysis of a large dataset from 17 research cruises (1990-2014) showed that the composition of particulate organic matter in the estuary changes after the freshet with decreasing organic carbon and nitrogen content, and increasing contribution of marine and autochthonous estuarine organic matter (based on PO13C and pigment ratios). Bacterial production rates (measured as leucine or thymidine incorporation rates) in the estuary respond to this change, and correlate strongly with labile particulate nitrogen concentration and temperature during individual sampling campaigns, and with the concentration of chlorophyll in the Columbia River across all seasons. Regression models suggest that the concentration of labile particulate nitrogen and the rate of bacterial production can be predicted from sensor measurements of turbidity, salinity, and temperature in the estuary and chlorophyll in the river. These results suggest that the quality of

  13. Efficiency of Respirator Filter Media against Diesel Particulate Matter: A Comparison Study Using Two Diesel Particulate Sources.

    PubMed

    Burton, Kerrie A; Whitelaw, Jane L; Jones, Alison L; Davies, Brian

    2016-07-01

    Diesel engines have been a mainstay within many industries since the early 1900s. Exposure to diesel particulate matter (DPM) is a major issue in many industrial workplaces given the potential for serious health impacts to exposed workers; including the potential for lung cancer and adverse irritant and cardiovascular effects. Personal respiratory protective devices are an accepted safety measure to mitigate worker exposure against the potentially damaging health impacts of DPM. To be protective, they need to act as effective filters against carbon and other particulates. In Australia, the filtering efficiency of respiratory protective devices is determined by challenging test filter media with aerosolised sodium chloride to determine penetration at designated flow rates. The methodology outlined in AS/NZS1716 (Standards Australia International Ltd and Standards New Zealand 2012. Respiratory protective devices. Sydney/Wellington: SAI Global Limited/Standards New Zealand) does not account for the differences between characteristics of workplace contaminants like DPM and sodium chloride such as structure, composition, and particle size. This study examined filtering efficiency for three commonly used AS/NZS certified respirator filter models, challenging them with two types of diesel emissions; those from a diesel generator and a diesel engine. Penetration through the filter media of elemental carbon (EC), total carbon (TC), and total suspended particulate (TSP) was calculated. Results indicate that filtering efficiency assumed by P2 certification in Australia was achieved for two of the three respirator models for DPM generated using the small diesel generator, whilst when the larger diesel engine was used, filtering efficiency requirements were met for all three filter models. These results suggest that the testing methodology specified for certification of personal respiratory protective devices by Standards Australia may not ensure adequate protection for

  14. High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

    DOEpatents

    Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

  15. High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

    DOEpatents

    Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

  16. Effects of Crayfish on Quality of Fine Particulate Organic Matter

    NASA Astrophysics Data System (ADS)

    Montemarano, J. J.; Kershner, M. W.; Leff, L. G.

    2005-05-01

    The origin and ontogeny of detritus often determines its bioavailability. Crayfish shred and consume detrital organic matter, influencing fine particulate organic matter (FPOM) availability, composition and quality. Given consumption of FPOM by many invertebrates, crayfish can indirectly affect these organisms by altering FPOM bioavailability through organic matter fragmentation, biofilm disturbance, and defecation. These effects may or may not vary among coarse particulate organic matter (CPOM) from different leaf species. To assess crayfish effects on FPOM quality, crayfish were fed stream-conditioned maple or oak leaves in hanging 1-mm mesh-bottom baskets in aquaria. After 12 h, crayfish and remaining leaves were removed. FPOM fragments that fell through the mesh were vacuum filtered and analyzed for percent organic matter, C:N ratio, and bacterial abundance. The same analyses were conducted on crayfish feces collected using finger cots encasing crayfish abdomens. C:N ratios did not differ between feces and maple leaf CPOM, but were lower in FPOM produced through fragmentation and disturbance (P = 0.023). Overall, crayfish alter the ontogeny of detritus, which may, in turn, affect stream FPOM dynamics.

  17. On the design of novel multifunctional materials by using particulate additives

    NASA Astrophysics Data System (ADS)

    Dunnigan, Ross Daniel

    This thesis has been organized into five chapters. The main focus of this thesis is to design novel multifunctional materials by using particulate additives. Chapter 1 is devoted to reviewing recent studies in additive manufacturing (AM) and other background information. In Chapter 2, the synthesis and characterization of novel Ti3SiC2-reinforced Zn-matrix composites is reported. During this study, all the Zn composites were hot pressed at 500°C for 5 min at a uniaxial pressure of ~150 MPa. Microstructure analysis by SEM (Scanning Electron Microscopy) and phase analysis by XRD (X-ray Diffraction) confirmed that there was minimal interfacial reaction between Ti3SiC 2 particles and the Zn matrix. The addition of Ti3SiC 2 improved the tribological performance of these composites against alumina substrates but did not have any beneficial effect on the mechanical performance. The addition of Ti3SiC2 particulates to metal and polymer matrices show interesting properties. Chapter 3 will focus on additive manufacturing of Ti3SiC2 particulates in a polymer matrix. Waste materials are a big problem in the world. Chapters 4 and 5 focus on recycling materials. The mechanical and tribological properties of the Resin-Nylon and ResinPolyester composites are reported, respectively.

  18. PRODUCTION OF SHEET FROM PARTICULATE MATERIAL

    DOEpatents

    Blainey, A.

    1959-05-12

    A process is presented for forming coherent sheet material from particulate material such as granular or powdered metal, granular or powdered oxide, slurries, pastes, and plastic mixes which cohere under pressure. The primary object is to avoid the use of expensive and/ or short lived pressing tools, that is, dies and specially profiled rolls, and so to reduce the cost of the product and to prcvide in a simple manner for the making of the product in a variety of shapes or sizes. The sheet material is formed when the particulate material is laterally confined in a boundary material deformable in all lateral directions under axial pressure and then axially compressing the layer of particulate material together with the boundary material.

  19. Method for dispersing catalyst onto particulate material

    DOEpatents

    Utz, Bruce R.; Cugini, Anthony V.

    1992-01-01

    A method for dispersing finely divided catalyst precursors onto the surface of coal or other particulate material includes the steps of forming a wet paste mixture of the particulate material and a liquid solution containing a dissolved transition metal salt, for instance a solution of ferric nitrate. The wet paste mixture is in a state of incipient wetness with all of this solution adsorbed onto the surfaces of the particulate material without the presence of free moisture. On adding a precipitating agent such as ammonia, a catalyst precursor such as hydrated iron oxide is deposited on the surfaces of the coal. The catalyst is activated by converting it to the sulfide form for the hydrogenation or direct liquefaction of the coal.

  20. Thermogravimetric analysis of diesel particulate matter

    NASA Astrophysics Data System (ADS)

    Lapuerta, M.; Ballesteros, R.; Rodríguez-Fernández, J.

    2007-03-01

    The regulated level of diesel particulate mass for 2008 light-duty diesel on-road engines will be 0.005 g km-1 in Europe. Measurements by weighing and analysis of this low level of particulate mass based on chemical extraction are costly, time consuming and hazardous because of the use of organic solvents, potentially carcinogenic. An alternative to this analysis is proposed here: a thermal mass analyser that measures the volatile fraction (VOF) as well as the soot fraction of the particulate matter (PM) collected on a cleaned fibre glass filter. This paper evaluates this new thermal mass measurement (TGA) as a possible alternative to the conventional chemical extraction method, and presents the results obtained with both methods when testing a diesel engine fuelled with a reference diesel fuel (REF), a pure biodiesel fuel (B100) and two blends with 30% and 70% v/v biodiesel (B30 and B70, respectively).

  1. The interplay between particulate and dissolved neodymium in the Western North Atlantic: First insights and interpretations

    NASA Astrophysics Data System (ADS)

    Stichel, T.; Kretschmer, S.; Lambelet, M.; van de Flierdt, T.; Rutgers van der Loeff, M.; Rijkenberg, M. J. A.; Gerringa, L. J.; De Baar, H. J. W.

    2014-12-01

    Dissolved neodymium (Nd) isotopes (expressed as ɛNd) have been widely used as a water mass tracer to reconstruct paleo ocean circulation. However, the marine geochemical cycle of Nd is not well understood. Unclear input mechanisms, scarcity of available data, and observed decoupling between dissolved ɛNd and Nd concentration patterns ([Nd]) are only a few of the unresolved issues. The latter is often referred to as the Nd paradox(e.g. Goldstein and Hemming 2003). Here we revisit this paradox with an unprecedented data set on particulate Nd isotope and concentration data from five stations along the Dutch GEOTRACES transect GA02 in the western North and equatorial Atlantic Ocean (cruises 64PE319 and 64PE321 from April to July 2010). Particulates were collected with in-situ pumps on 0.8 µm Supor filters and subjected to a total digestion procedure in the home laboratory. The particulates collected farthest north (Irminger Sea and Labrador Sea) show a strong affinity to the nearby land masses in their Nd isotope composition: Very negative values (ɛNd ≈-20) are observed in the Labrador Sea, which is surrounded by old continental rocks. More positive values of up to ɛNd ≈-4 are found east of Greenland probably derived from the Nansen Fjord Formation's basaltic rocks. In these two areas the particulate ɛNd is offset from dissolved Nd isotopes by up to 7.7 ɛ-units, but reveals a similar vertical distribution. Further downstream of the flow path of the North Atlantic Deep Water, dissolved and particulate Nd isotopic compositions in the water column seem to merge and become indistinguishable from one another south of Bermuda (BATS station). This seems to indicate that particulate and dissolved fractions exchange with increasing distance from source regions and age of water masses. Neodymium concentrations in particulates [pNd] are low (KD<5%) and invariant. However, most stations show a significant increase in [pNd] close to the seafloor, where [pNd] nearly

  2. Characterization of coarse particulate matter in school gyms.

    PubMed

    Braniš, Martin; Šafránek, Jiří

    2011-05-01

    We investigated the mass concentration, mineral composition and morphology of particles resuspended by children during scheduled physical education in urban, suburban and rural elementary school gyms in Prague (Czech Republic). Cascade impactors were deployed to sample the particulate matter. Two fractions of coarse particulate matter (PM(10-2.5) and PM(2.5-1.0)) were characterized by gravimetry, energy dispersive X-ray spectrometry and scanning electron microscopy. Two indicators of human activity, the number of exercising children and the number of physical education hours, were also recorded. Lower mass concentrations of coarse particulate matter were recorded outdoors (average PM(10-2.5) 4.1-7.4 μg m(-3) and PM(2.5-1.0) 2.0-3.3 μg m(-3)) than indoors (average PM(10-2.5) 13.6-26.7 μg m(-3) and PM(2.5-1.0) 3.7-7.4 μg m(-3)). The indoor concentrations of coarse aerosol were elevated during days with scheduled physical education with an average indoor-outdoor (I/O) ratio of 2.5-16.3 for the PM(10-2.5) and 1.4-4.8 for the PM(2.5-1.0) values. Under extreme conditions, the I/O ratios reached 180 (PM(10-2.5)) and 19.1 (PM(2.5-1.0)). The multiple regression analysis based on the number of students and outdoor coarse PM as independent variables showed that the main predictor of the indoor coarse PM concentrations is the number of students in the gym. The effect of outdoor coarse PM was weak and inconsistent. The regression models for the three schools explained 60-70% of the particular dataset variability. X-ray spectrometry revealed 6 main groups of minerals contributing to resuspended indoor dust. The most abundant particles were those of crustal origin composed of Si, Al, O and Ca. Scanning electron microscopy showed that, in addition to numerous inorganic particles, various types of fibers and particularly skin scales make up the main part of the resuspended dust in the gyms. In conclusion, school gyms were found to be indoor microenvironments with high

  3. Particulate hot gas stream cleanup technical issues

    SciTech Connect

    Pontius, D.H.; Snyder, T.R.

    1999-09-30

    The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

  4. Much ado about dioxides and particulates

    SciTech Connect

    Doane, F.P.

    1980-02-01

    Technical feature: The effect of carbon dioxide on climate is uncertain, and recent high CO2 levels may not persist. Worldwide warming trends since 1840 are outlined. There is no conclusive evidence that increased burning of fossil fuels has had or will have any ill effect on the climate. While there has been a slight increase in the CO2 content of the atmosphere, the oxidation of humus and bogs rather than fossil fuels seems to be the main source of increased atmospheric CO2 and particulates. Increased plant growth and adsorption of CO2 and particulates by the oceans will maintain an even balance in the atmosphere. (17 references, 2 tables)

  5. [Suspended particulates and lung health].

    PubMed

    Neuberger, Manfred; Moshammer, Hanns

    2004-01-01

    Based on several severe air pollution episodes, a temporal correlation between high concentrations of particulate matter (PM) and SO2 pollution and acute increases in respiratory and cardiopulmonary mortality had been established in Vienna for the 1970's. After air pollution had decreased in Austria in the 1980's--as documented by data on SO2, and total suspended particles (TSP)--no such associations between day-to-day changes of SO2 and TSP and mortality have been documented any more, however, traffic related pollutants like fine particles and NO2 remained a problem. Therefore, short term effects of PM on lung function, morbidity and mortality were investigated in Vienna, Linz, Graz and a rural control area. Long-term exposure and chronic disease--even more important for public health--were studied in repeated cross-sectional, a mixed longitudinal and a birth cohort study on school children in the city of Linz. Lung function growth was found impaired from long-term exposure to air pollutants and improved in districts where ambient air pollution had decreased. Where only TSP and SO2 had decreased, no continuous improvement of small airway function was found and end-expiratory flow rates stayed impaired where NO2-reduction from technical improvements of cars and industry was counterbalanced by increase of motorized (diesel) traffic. Remaining acute effects of ambient air pollution in 2001 from PM, NO2 and co-pollutants found in a time series study also show that continuing efforts are necessary. Active surface of particles inhaled several hours to days before spirometry was found related to short-term reductions in forced vital capacity-FVC (p<0.01), forced expiratory volume in one second-FEV1 (p<0.01) and maximal expiratory flow rate at 50% of vital capacity-MEF50 (p<0.05). In pupils with asthma or previous airway obstruction 4-week-diaries proved that the following symptoms increased with acute exposure to higher active surface of particles: wheezing (p<0

  6. Processing and damage recovery of intrinsic self-healing glass fiber reinforced composites

    NASA Astrophysics Data System (ADS)

    Sordo, Federica; Michaud, Véronique

    2016-08-01

    Glass fiber reinforced composites with a self-healing, supramolecular hybrid network matrix were produced using a modified vacuum assisted resin infusion moulding process adapted to high temperature processing. The quality and fiber volume fraction (50%) of the obtained materials were assessed through microscopy and matrix burn-off methods. The thermo-mechanical properties were quantified by means of dynamic mechanical analysis, revealing very high damping properties compared to traditional epoxy-based glass fiber reinforced composites. Self-healing properties were assessed by three-point bending tests. A high recovery of the flexural properties, around 72% for the elastic modulus and 65% of the maximum flexural stress, was achieved after a resting period of 24 h at room temperature. Recovery after low velocity impact events was also visually observed. Applications for this intrinsic and autonomic self-healing highly reinforced composite material point towards semi-structural applications where high damping and/or integrity recovery after impact are required.

  7. Direct and quantitative photothermal absorption spectroscopy of individual particulates

    SciTech Connect

    Tong, Jonathan K.; Hsu, Wei-Chun; Eon Han, Sang; Burg, Brian R.; Chen, Gang; Zheng, Ruiting; Shen, Sheng

    2013-12-23

    Photonic structures can exhibit significant absorption enhancement when an object's length scale is comparable to or smaller than the wavelength of light. This property has enabled photonic structures to be an integral component in many applications such as solar cells, light emitting diodes, and photothermal therapy. To characterize this enhancement at the single particulate level, conventional methods have consisted of indirect or qualitative approaches which are often limited to certain sample types. To overcome these limitations, we used a bilayer cantilever to directly and quantitatively measure the spectral absorption efficiency of a single silicon microwire in the visible wavelength range. We demonstrate an absorption enhancement on a per unit volume basis compared to a thin film, which shows good agreement with Mie theory calculations. This approach offers a quantitative approach for broadband absorption measurements on a wide range of photonic structures of different geometric and material compositions.

  8. Hybridized polymer matrix composites

    NASA Technical Reports Server (NTRS)

    London, A.

    1981-01-01

    Design approaches and materials are described from which are fabricated pyrostatic graphite/epoxy (Gr/Ep) laminates that show improved retention of graphite particulates when subjected to burning. Sixteen hybridized plus two standard Gr/Ep laminates were designed, fabricated, and tested in an effort to eliminate the release of carbon (graphite) fiber particles from burned/burning, mechanically disturbed samples. The term pyrostatic is defined as meaning mechanically intact in the presence of fire. Graphite particulate retentive laminates were constructed whose constituent materials, cost of fabrication, and physical and mechanical properties were not significantly different from existing Gr/Ep composites. All but one laminate (a Celion graphite/bis-maleimide polyimide) were based on an off-the-shelf Gr/Ep, the AS-1/3501-5A system. Of the 16 candidates studied, four thin (10-ply) and four thick (50-ply) hybridized composites are recommended.

  9. Qualitative and quantitative determination of water in airborne particulate matter

    NASA Astrophysics Data System (ADS)

    Canepari, S.; Farao, C.; Marconi, E.; Giovannelli, C.; Perrino, C.

    2012-10-01

    This paper describes the optimization and validation of a new simple method for the quantitative determination of water in atmospheric particulate matter (PM). The analyses are performed by using a coulometric Karl-Fisher system equipped with a controlled heating device; different water contributions are separated by the application of an optimized thermal ramp (three heating steps: 50-120 °C, 120-180 °C, 180-250 °C). The analytical performance of the method was verified by using standard materials containing 5.55% and 1% by weight of water. The recovery was greater than 95%; the detection limit was about 20 μg. The method was then applied to NIST reference materials (NIST1649a, urban particulate matter) and to real PM10 samples collected in different geographical areas. In all cases the repeatability was satisfactory (10-15%). When analyzing the reference material, the separation of four different types of water was obtained. In real PM10 samples the amount of water and its thermal profile differed as a function of the chemical composition of the dust. Mass percentages of 3-4% of water were obtained in most samples, but values up to about 15% were reached in areas where the chemical composition of PM is dominated by secondary inorganic ions and organic matter. High percentages of water were also observed in areas where PM is characterized by the presence of desert dust. A possible identification of the quality of water released from the samples was tried by applying the method to some hygroscopic compounds that are likely contained in PM (pure SiO2, Al2O3, ammonium salts, carbohydrates and dicarboxylic acids) and by comparing the results with those obtained from field samples.

  10. Qualitative and quantitative determination of water in airborne particulate matter

    NASA Astrophysics Data System (ADS)

    Canepari, S.; Farao, C.; Marconi, E.; Giovannelli, C.; Perrino, C.

    2013-02-01

    This paper describes the optimization and validation of a new simple method for the quantitative determination of water in atmospheric particulate matter (PM). The analyses are performed by using a coulometric Karl-Fisher system equipped with a controlled heating device; different water contributions are separated by the application of an optimized thermal ramp (three heating steps: 50-120 °C, 120-180 °C, 180-250 °C). The analytical performance of the method was verified by using standard materials containing 5.55% and 1% by weight of water. The recovery was greater than 95%; the detection limit was about 20 μg. The method was then applied to NIST Reference Materials (NIST1649a, urban particulate matter) and to real PM10 samples collected in different geographical areas. In all cases the repeatability was satisfactory (10-15%). When analyzing the Reference Material, the separation of four different types of water was obtained. In real PM10 samples the amount of water and its thermal profile differed as a function of the chemical composition of the dust. Mass percentages of 3-4% of water were obtained in most samples, but values up to about 15% were reached in areas where the chemical composition of PM is dominated by secondary inorganic ions and organic matter. High percentages of water were also observed in areas where PM is characterized by the presence of desert dust. A possible identification of the quality of water released from the samples was tried by applying the method to some hygroscopic compounds that are likely contained in PM (pure SiO2, Al2O3, ammonium salts, carbohydrates and dicarboxylic acids) and by comparing the results with those obtained from field samples.

  11. Particulate emissions from commercial shipping: Chemical, physical, and optical properties

    NASA Astrophysics Data System (ADS)

    Lack, Daniel A.; Corbett, James J.; Onasch, Timothy; Lerner, Brian; Massoli, Paola; Quinn, Patricia K.; Bates, Timothy S.; Covert, David S.; Coffman, Derek; Sierau, Berko; Herndon, Scott; Allan, James; Baynard, Tahllee; Lovejoy, Edward; Ravishankara, A. R.; Williams, Eric

    2009-04-01

    We characterize particulate emissions on the basis of chemical, physical, and optical properties from commercial vessels. Observations during the Texas Air Quality Study/Gulf of Mexico Atmospheric Composition and Climate Study 2006 field campaign provide chemical and physical characteristics including sulfate (SO42-) mass, organic matter (OM) mass, black carbon (BC) mass, particulate matter (PM) mass, number concentrations (condensation nuclei (CN) > 5 nm), and cloud condensation nuclei (CCN). Optical characterization included multiple wavelength visible light absorption and extinction, extinction relative humidity dependence, and single scatter albedo (SSA). The global contribution of shipping PM was calculated to be 0.90 Tg a-1, in good agreement with previous inventories (0.91 and 1.13 Tg a-1 from Eyring et al. (2005a) and Wang et al. [2008]). Observed PM composition was 46% SO42-, 39% OM, and 15% BC and differs from inventories that used 81%, 14%, and 5% and 31%, 63%, and 6% SO42-, OM, and BC, respectively. SO42- and OM mass were found to be dependent on fuel sulfur content as were SSA, hygroscopicity, and CCN concentrations. BC mass was dependent on engine type and combustion efficiency. A plume evolution study conducted on one vessel showed conservation of particle light absorption, decrease in CN > 5 nm, increase in particle hygroscopicity, and an increase in average particle size with distance from emission. These results suggest emission of small nucleation mode particles that subsequently coagulate/condense onto larger BC and OM. This work contributes to an improved understanding of the impacts of ship emissions on climate and air quality and will also assist in determining potential effects of altering fuel standards.

  12. 76 FR 5270 - Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Particulate Matter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... particulates can cause heart and lung disease. Particulate matter also aggravates asthma. Airborne particulate... more for fine particulates. WPC states that it would be difficult for sources to limit PM 2.5...

  13. Miniature Sensors for Airborne Particulate Matter

    EPA Science Inventory

    Our group is working to design a small,lightweight, low-cost real-time particulate matter(PM) sensor to enable better monitoring of PMconcentrations in air, with the goal of informingpolicymakers and regulators to provide betterpublic health. The sensor reads the massconcentratio...

  14. Particulate control system for biomass firing technologies

    SciTech Connect

    Easom, B.H.; Smolensky, L.A.; Wysk, S.R.

    1996-12-31

    The new particulate control equipment, the so-called Core Separator, overcomes most of the limitations inherent in conventional particulate control systems and can be effectively adapted for biomass applications. The Core Separator is a mechanical collector; however, this technology overcomes the performance limitation inherent in cyclones by performing the tasks of separation and collection in two separate components. The separation process is less affected by secondary flows and is much more efficient than the collection process. Also, the components of the system are arranged in such a way that the separation process determines the system efficiency. As a result, particulate emission rates downstream of this system are one fourth of those from the most efficient cyclones. This technology has been demonstrated through commercial unit installations in the U.S. and abroad. It has been used for industrial separations including coal fly ash, minerals, and chemical recovery applications. It is considered a lower-cost alternative to fabric filters and electrostatic precipitators, albeit one that can meet or exceed regulations for particulate emissions. Development of this technology has been funded by the U.S. Department of Energy, Environmental Protection Agency, and Electric Power Research Institute.

  15. SPATIAL PREDICTION OF FINE PARTICULATE MATTER

    EPA Science Inventory

    A new national monitoring network for the measurement of fine particular matter (PM2.5) is currently under development. A primary goal of this network is to collect monitoring data in residential communities for the evaluation of compliance with particulate air quality standards...

  16. Control Techniques for Particulate Air Pollutants.

    ERIC Educational Resources Information Center

    National Air Pollution Control Administration (DHEW), Washington, DC.

    Included is a comprehensive review of the approaches commonly recommended for controlling the sources of particulate air pollution. Not all possible combinations of control techniques that might bring about more stringent control of each individual source are reviewed. The many agricultural, commercial, domestic, industrial, and municipal…

  17. REINVENTING PERSONAL EXPOSURE TO PARTICULATE MATTER

    EPA Science Inventory

    Recent epidemiologic studies of modern air pollution show statistically significant relationships between fluctuations of daily non-trauma mortality and fluctuations of daily ambient particulate matter (PM) levels at low concentrations. A review of historic smoke-fog (smog)episo...

  18. FINE PARTICULATE MATTER EMISSIONS FROM CANDLES

    EPA Science Inventory

    The paper gives reulst of testing five types of candles, purchased from local stores, for fine particulate matter (PM) emissions under close-to-realistic conditions in a research house. The test method allows for determination of both the emission and deposition rates. Most tes...

  19. Holographic Investigation of Solid Propellant Particulates.

    DTIC Science & Technology

    1981-12-01

    Science and Engineering Ii ABSTRACT This investigation completed the development process to establish a technique to obtain holographic recordings of...13 C. EXPERIMENTAL TECHNIQUE --------------------------------- 20 0. DISCUSSION...conditions (pressure, etc.) to the behavior of the particulates within the propellant port and through the nozzle. Four experimental techniques are being

  20. Trace gas and particulate emissions from biomass burning in temperate ecosystems

    NASA Technical Reports Server (NTRS)

    Cofer, Wesley R., III; Levine, Joel S.; Winstead, Edward L.; Stocks, Brian J.

    1991-01-01

    Emissions measured from fires in graminoid wetlands, Mediterranean chaparrals, and boreal forests, suggest that such ecosystemic parameters as fuel size influence combustion emissions in ways that are broadly predictable. The degree of predictability is most noticeable when wetland fire-related results are compared with boreal forest emissions; the inorganic fraction of the particulate emissions is close in composition irrespective of the ecosystem. It is found that both aerosol and trace gas emissions are influenced by the phase of combustion.

  1. Instrumentation for Nano-porous, Nano-particulate Geopolymeric Materials Research

    DTIC Science & Technology

    2008-11-04

    nano-sized high surface area ceramic powders in geopolymers and geopolymeric composites. On the other hand, the Thinky ARE-250 mixer was purchased to...DATES COVERED (From - To) 6/15/07 - 6/14/08 4. TITLE AND SUBTITLE Instrumentation for Nano-porous, Nano-particulate Geopolymeric Materials... Geopolymers are a new class of ceramic materials which are best understood as rigid inorganic, aluminosilicate, hydrated gels, charge-balanced by cations

  2. Instrumentation for Nano-porous, Nano-particulate Geopolymeric Materials Research

    DTIC Science & Technology

    2008-11-04

    surface area ceramic powders in geopolymers and geopolymeric composites. On the other hand, the Thinky ARE-250 mixer was purchased to assist with...3. DATES COVERED (From - To) 6/15/07 – 6/14/08 4. TITLE AND SUBTITLE Instrumentation for Nano-porous, Nano-particulate Geopolymeric ...STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT -- Geopolymers are a new class of ceramic materials which are best understood as rigid

  3. Source apportionment of particulate matter in Denmark

    NASA Astrophysics Data System (ADS)

    Moenster, J.; Glasius, M.; Nielsen, O. J.; Bilde, M.; Jensen, F. P.

    2005-12-01

    Atmospheric particulate matter (PM) has received considerable attention over the last decade as an important component of air pollution, particularly due to its health effects on the exposed population. Typically the mass of particles with diameters smaller that 10 μm (PM10) has been used in large cohort studies to estimate health effects such as increase in hospitalization rate, asthma attacks and premature deaths. Particles smaller than 2.5 μm (PM2.5) and ultra fine particles have been used in various epidemiological studies and correlations between exposure to fine and ultra fine particles and health effects have been found. Limits of acceptable concentrations of PM10, PM2.5 and some carcinogenic species have been made, and it is important to find the origin of the particulate matter to prevent exceeds of these limits. This can be done by measuring particle mass, organic/inorganic fractions of particles, the chemical components and other relevant factors, and then use receptor modeling for source apportionment of the particulate matter. We have done measurements at street level and urban background in Copenhagen, Denmark, to determine the origin of different sizes of particulate matter and the toxic organic compounds connected to these particles. We also did measurements in a small village with less traffic and more residential wood combustion for a comparison between traffic and wood combustion generated pollution. Our results show a significant amount of particulate matter coming from non local sources and are dominated by long-range transported inorganic salts. The amount of these is highly depended on the wind direction and thus on the origin of the wind plume. The origin of the carcinogenic organic compound benzo(a)pyrene was found to be local combustion sources. To prevent events of high particulate matter concentration in Copenhagen, Denmark, a reduction of emission from the local traffic will only lead to a minor effect, since the majority of the

  4. Development of Particulates and Aerosols Research

    NASA Technical Reports Server (NTRS)

    DeWitt, Kenneth; Rivera, Monica

    2005-01-01

    During the past year several accomplishments were made for both the Particulate Matter Characterization and Measurement System, (PMCMS) and PAGEMS projects. The PAGEMS focus is to measure particulate emissions as a function of combustor parameters such as inlet temperature, inlet pressure and fuel air ratio. These measurements are used to evaluate combustor performance in hopes of correlating particulate emissions with engine conditions. These measurements have taken place at in-house NASA combustor facilities and off-site facilities. Ths work is unique because particulate measurements at high- pressure conditions are not commonly made. Some calibration of the PAGEMS instrumentation was done as well as minor modifications to the PAGEMS plumbing setup. These led to measurement improvements. The instrumentation and measurement process for PAGEMS was assessed and new instruments such as a thermodenuder, thermal mass flow meters and a cyclone separator were purchased to improve the PAGEMS instrumentation and measurement process. A worksheet was created to simulate varying inlet conditions to the DMA. This worksheet allows the user to assess the error in the measurements when certain conditions exist. Two technical papers were written with the PAGEMS team for the EXCAVATE field project. A paper was also reviewed for an in house publication. Also data was processed and analyzed for another field project (PAX) and will be part of a third PAGEMS paper. Accomplishments were also made with the PMCMS project. The calibration of the radial differential mobility analyzer, (RDMA) in the particle sizing system in the PMCMS was completed and provided satisfactory results. The voltages used for the RDMA depending on the particle of interest were corrected. The measurement capability of the PMCMS was increased by replacing the MetOne CPC with a TSI CPC. Lastly, assistance was provided to three college summer students with calibration of their particulate equipment and Monica Rivera

  5. Particulate Emissions from a Pre-Emissions Control Era Spark-Ignition Vehicle: A Historical Benchmark

    SciTech Connect

    John M.E. Storey; C. Scott Sluder; Douglas A. Blom; Erin Higinbotham

    2000-06-19

    This study examined the particulate emissions from a pre-emissions control era vehicle operated on both leaded and unleaded fuels for the purpose of establishing a historical benchmark. A pre-control vehicle was located that had been rebuilt with factory original parts to approximate an as-new vehicle prior to 1968. The vehicle had less than 20,000 miles on the rebuilt engine and exhaust. The vehicle underwent repeated FTP-75 tests to determine its regulated emissions, including particulate mass. Additionally, measurements of the particulate size distribution were made, as well as particulate lead concentration. These tests were conducted first with UTG96 certification fuel, followed by UTG96 doped with tetraethyl lead to approximate 1968 levels. Results of these tests, including transmission electron micrographs of individual particles from both the leaded and unleaded case are presented. The FTP composite PM emissions from this vehicle averaged 40.5 mg/mile using unleaded fuel. The results from the leaded fuel tests showed that the FTP composite PM emissions increased to an average of 139.5 mg/mile. Analysis of the particulate size distribution for both cases demonstrated that the mass-based size distribution of particles for this vehicle is heavily skewed towards the nano-particle range. The leaded-fuel tests showed a significant increase in mass concentration at the <0.1 micron size compared with the unleaded-fuel test case. The leaded-fuel tests produced lead emissions of nearly 0.04 g/mi, more than a 4-order-of-magnitude difference compared with unleaded-fuel results. Analysis of the size-fractionated PM samples showed that the lead PM emissions tended to be distributed in the 0.25 micron and smaller size range.

  6. Electrically heated particulate filter preparation methods and systems

    DOEpatents

    Gonze, Eugene V [Pinckney, MI

    2012-01-31

    A control system that controls regeneration of a particulate filter is provided. The system generally includes a fuel control module that controls injection of fuel into exhaust that passes through the particulate filter. A regeneration module controls current to the particulate filter to initiate regeneration after the fuel has been injected into the exhaust.

  7. 40 CFR 60.182 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.182... Smelters § 60.182 Standard for particulate matter. (a) On and after the date on which the performance test... furnace, or sintering machine discharge end any gases which contain particulate matter in excess of 50...

  8. 40 CFR 60.52 - Standard for particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for particulate matter. 60.52... § 60.52 Standard for particulate matter. (a) On and after the date on which the initial performance... atmosphere from any affected facility any gases which contain particulate matter in excess of 0.18 g/dscm...

  9. 40 CFR 60.122 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.122... Smelters § 60.122 Standard for particulate matter. (a) On and after the date on which the performance test... furnace any gases which: (1) Contain particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  10. 40 CFR 52.2059 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Particulate matter... Control strategy: Particulate matter. (a) Pennsylvania has committed to undertake a comprehensive program... Investigating and Controlling Nontraditional Particulate Matter Emissions Task Completion date Scheduled...

  11. 40 CFR 60.282 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.282... § 60.282 Standard for particulate matter. (a) On and after the date on which the performance test...: (i) Contain particulate matter in excess of 0.10 g/dscm (0.044 gr/dscf) corrected to 8 percent...

  12. 40 CFR 60.92 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.92... Facilities § 60.92 Standard for particulate matter. (a) On and after the date on which the performance test... which: (1) Contain particulate matter in excess of 90 mg/dscm (0.04 gr/dscf). (2) Exhibit 20...

  13. 40 CFR 60.472 - Standards for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for particulate matter. 60... Processing and Asphalt Roofing Manufacture § 60.472 Standards for particulate matter. (a) On and after the...) Particulate matter in excess of: (i) 0.04 kg/Mg (0.08 lb/ton) of asphalt shingle or mineral-surfaced...

  14. 40 CFR 52.2584 - Control strategy; Particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy; Particulate matter... Control strategy; Particulate matter. (a) Part D—Disapproval—USEPA disapproves Regulation NR 154.11(7)(b... control strategy to attain and maintain the standards for particulate matter, because it does not...

  15. 40 CFR 60.52 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.52... § 60.52 Standard for particulate matter. (a) On and after the date on which the initial performance... atmosphere from any affected facility any gases which contain particulate matter in excess of 0.18 g/dscm...

  16. 40 CFR 52.427 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy: Particulate matter...: Particulate matter. (a) Determination of attainment. EPA has determined, as of May 16, 2012, that based on... fine particulate matter (PM2.5) nonattainment area has attained the 2006 24-hour PM2.5 national...

  17. 40 CFR 60.472 - Standards for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for particulate matter. 60... Processing and Asphalt Roofing Manufacture § 60.472 Standards for particulate matter. (a) On and after the...) Particulate matter in excess of: (i) 0.04 kg/Mg (0.08 lb/ton) of asphalt shingle or mineral-surfaced...

  18. 40 CFR 52.2584 - Control strategy; Particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy; Particulate matter... Control strategy; Particulate matter. (a) Part D—Disapproval—USEPA disapproves Regulation NR 154.11(7)(b... control strategy to attain and maintain the standards for particulate matter, because it does not...

  19. 40 CFR 60.382 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.382... Processing Plants § 60.382 Standard for particulate matter. (a) On and after the date on which the... stack emissions that: (1) Contain particulate matter in excess of 0.05 grams per dry standard...

  20. 40 CFR 60.172 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.172... Smelters § 60.172 Standard for particulate matter. (a) On and after the date on which the performance test... contain particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  1. 40 CFR 60.142a - Standards for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for particulate matter. 60... 20, 1983 § 60.142a Standards for particulate matter. (a) Except as provided under paragraphs (b) and...-blown BOPF and contain particulate matter in excess of 23 mg/dscm (0.010 gr/dscf). (3) Exit from...

  2. 40 CFR 52.427 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy: Particulate matter...: Particulate matter. (a) Determination of attainment. EPA has determined, as of May 16, 2012, that based on... fine particulate matter (PM2.5) nonattainment area has attained the 2006 24-hour PM2.5 national...

  3. 40 CFR 52.1476 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Particulate matter... strategy: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standards for particulate matter...

  4. 40 CFR 60.182 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.182... Smelters § 60.182 Standard for particulate matter. (a) On and after the date on which the performance test... furnace, or sintering machine discharge end any gases which contain particulate matter in excess of 50...

  5. 40 CFR 60.402 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.402... Plants § 60.402 Standard for particulate matter. (a) On and after the date on which the performance test... which: (i) Contain particulate matter in excess of 0.030 kilogram per megagram of phosphate rock feed...

  6. 40 CFR 60.292 - Standards for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for particulate matter. 60... Manufacturing Plants § 60.292 Standards for particulate matter. (a) On and after the date on which the..., particulate matter at emission rates exceeding those specified in table CC-1, Column 2 and Column...

  7. 40 CFR 52.1476 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Particulate matter... strategy: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standards for particulate matter...

  8. 40 CFR 60.162 - Standard for particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for particulate matter. 60.162... Smelters § 60.162 Standard for particulate matter. (a) On and after the date on which the performance test... particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  9. 40 CFR 60.342 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.342... Manufacturing Plants § 60.342 Standard for particulate matter. (a) On and after the date on which the... gases which: (1) Contain particulate matter in excess of 0.30 kilogram per megagram (0.60 lb/ton)...

  10. 40 CFR 52.2584 - Control strategy; Particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy; Particulate matter... Control strategy; Particulate matter. (a) Part D—Disapproval—USEPA disapproves Regulation NR 154.11(7)(b... control strategy to attain and maintain the standards for particulate matter, because it does not...

  11. 40 CFR 60.302 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.302... § 60.302 Standard for particulate matter. (a) On and after the 60th day of achieving the maximum... a grain dryer any process emission which: (1) Contains particulate matter in excess of 0.023...

  12. 40 CFR 52.776 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy: Particulate matter...: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for attainment and maintenance of the secondary standards for particulate matter in...

  13. 40 CFR 60.92 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.92... Facilities § 60.92 Standard for particulate matter. (a) On and after the date on which the performance test... which: (1) Contain particulate matter in excess of 90 mg/dscm (0.04 gr/dscf). (2) Exhibit 20...

  14. 40 CFR 52.2584 - Control strategy; Particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy; Particulate matter... Control strategy; Particulate matter. (a) Part D—Disapproval—USEPA disapproves Regulation NR 154.11(7)(b... control strategy to attain and maintain the standards for particulate matter, because it does not...

  15. 40 CFR 60.162 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.162... Smelters § 60.162 Standard for particulate matter. (a) On and after the date on which the performance test... particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  16. 40 CFR 60.272a - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60... Standard for particulate matter. (a) On and after the date of which the performance test required to be... control device and contain particulate matter in excess of 12 mg/dscm (0.0052 gr/dscf); (2) Exit from...

  17. 40 CFR 60.92 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.92... Facilities § 60.92 Standard for particulate matter. (a) On and after the date on which the performance test... which: (1) Contain particulate matter in excess of 90 mg/dscm (0.04 gr/dscf). (2) Exhibit 20...

  18. 40 CFR 60.292 - Standards for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for particulate matter. 60... Manufacturing Plants § 60.292 Standards for particulate matter. (a) On and after the date on which the..., particulate matter at emission rates exceeding those specified in table CC-1, Column 2 and Column...

  19. 40 CFR 60.682 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.682... Insulation Manufacturing Plants § 60.682 Standard for particulate matter. On and after the date on which the... gases which contain particulate matter in excess of 5.5 kg/Mg (11.0 1b/ton) of glass pulled....

  20. 40 CFR 60.142a - Standards for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for particulate matter. 60... 20, 1983 § 60.142a Standards for particulate matter. (a) Except as provided under paragraphs (b) and...-blown BOPF and contain particulate matter in excess of 23 mg/dscm (0.010 gr/dscf). (3) Exit from...

  1. 40 CFR 60.182 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.182... Smelters § 60.182 Standard for particulate matter. (a) On and after the date on which the performance test... furnace, or sintering machine discharge end any gases which contain particulate matter in excess of 50...

  2. 40 CFR 60.282 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.282... § 60.282 Standard for particulate matter. (a) On and after the date on which the performance test...: (i) Contain particulate matter in excess of 0.10 g/dscm (0.044 gr/dscf) corrected to 8 percent...

  3. 40 CFR 60.162 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.162... Smelters § 60.162 Standard for particulate matter. (a) On and after the date on which the performance test... particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  4. 40 CFR 60.92 - Standard for particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for particulate matter. 60.92... Facilities § 60.92 Standard for particulate matter. (a) On and after the date on which the performance test... which: (1) Contain particulate matter in excess of 90 mg/dscm (0.04 gr/dscf). (2) Exhibit 20...

  5. 40 CFR 60.342 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.342... Manufacturing Plants § 60.342 Standard for particulate matter. (a) On and after the date on which the... gases which: (1) Contain particulate matter in excess of 0.30 kilogram per megagram (0.60 lb/ton)...

  6. 40 CFR 60.182 - Standard for particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for particulate matter. 60.182... Smelters § 60.182 Standard for particulate matter. (a) On and after the date on which the performance test... furnace, or sintering machine discharge end any gases which contain particulate matter in excess of 50...

  7. 40 CFR 60.282 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.282... § 60.282 Standard for particulate matter. (a) On and after the date on which the performance test...: (i) Contain particulate matter in excess of 0.10 g/dscm (0.044 gr/dscf) corrected to 8 percent...

  8. 40 CFR 60.682 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.682... Insulation Manufacturing Plants § 60.682 Standard for particulate matter. On and after the date on which the... gases which contain particulate matter in excess of 5.5 kg/Mg (11.0 1b/ton) of glass pulled....

  9. 40 CFR 52.1476 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Particulate matter... strategy: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standards for particulate matter...

  10. 40 CFR 52.776 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy: Particulate matter...: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for attainment and maintenance of the secondary standards for particulate matter in...

  11. 40 CFR 52.1476 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Particulate matter... strategy: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standards for particulate matter...

  12. 40 CFR 60.172 - Standard for particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for particulate matter. 60.172... Smelters § 60.172 Standard for particulate matter. (a) On and after the date on which the performance test... contain particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  13. 40 CFR 60.162 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.162... Smelters § 60.162 Standard for particulate matter. (a) On and after the date on which the performance test... particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  14. 40 CFR 60.302 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.302... § 60.302 Standard for particulate matter. (a) On and after the 60th day of achieving the maximum... a grain dryer any process emission which: (1) Contains particulate matter in excess of 0.023...

  15. 40 CFR 60.342 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.342... Manufacturing Plants § 60.342 Standard for particulate matter. (a) On and after the date on which the... gases which: (1) Contain particulate matter in excess of 0.30 kilogram per megagram (0.60 lb/ton)...

  16. 40 CFR 60.402 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.402... Plants § 60.402 Standard for particulate matter. (a) On and after the date on which the performance test... which: (i) Contain particulate matter in excess of 0.030 kilogram per megagram of phosphate rock feed...

  17. 40 CFR 60.142a - Standards for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for particulate matter. 60... 20, 1983 § 60.142a Standards for particulate matter. (a) Except as provided under paragraphs (b) and...-blown BOPF and contain particulate matter in excess of 23 mg/dscm (0.010 gr/dscf). (3) Exit from...

  18. 40 CFR 60.282 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.282... § 60.282 Standard for particulate matter. (a) On and after the date on which the performance test...: (i) Contain particulate matter in excess of 0.10 g/dscm (0.044 gr/dscf) corrected to 8 percent...

  19. 40 CFR 52.2059 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Particulate matter... Control strategy: Particulate matter. (a) Pennsylvania has committed to undertake a comprehensive program... Investigating and Controlling Nontraditional Particulate Matter Emissions Task Completion date Scheduled...

  20. 40 CFR 52.776 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy: Particulate matter...: Particulate matter. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for attainment and maintenance of the secondary standards for particulate matter in...

  1. 40 CFR 52.776 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy: Particulate matter...: Particulate matter. Link to an amendment published at 78 FR 28507, May 15, 2013. (a) The requirements of... the secondary standards for particulate matter in the Metropolitan Indianapolis Intrastate Region....

  2. 40 CFR 60.92 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.92... Facilities § 60.92 Standard for particulate matter. (a) On and after the date on which the performance test... which: (1) Contain particulate matter in excess of 90 mg/dscm (0.04 gr/dscf). (2) Exhibit 20...

  3. 40 CFR 60.302 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.302... § 60.302 Standard for particulate matter. (a) On and after the 60th day of achieving the maximum... a grain dryer any process emission which: (1) Contains particulate matter in excess of 0.023...

  4. 40 CFR 52.2059 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy: Particulate matter... Control strategy: Particulate matter. (a) Pennsylvania has committed to undertake a comprehensive program... Investigating and Controlling Nontraditional Particulate Matter Emissions Task Completion date Scheduled...

  5. 40 CFR 60.52 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.52... § 60.52 Standard for particulate matter. (a) On and after the date on which the initial performance... atmosphere from any affected facility any gases which contain particulate matter in excess of 0.18 g/dscm...

  6. 40 CFR 60.142a - Standards for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for particulate matter. 60... 20, 1983 § 60.142a Standards for particulate matter. (a) Except as provided under paragraphs (b) and...-blown BOPF and contain particulate matter in excess of 23 mg/dscm (0.010 gr/dscf). (3) Exit from...

  7. 40 CFR 60.292 - Standards for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for particulate matter. 60... Manufacturing Plants § 60.292 Standards for particulate matter. (a) On and after the date on which the..., particulate matter at emission rates exceeding those specified in table CC-1, Column 2 and Column...

  8. 40 CFR 60.162 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.162... Smelters § 60.162 Standard for particulate matter. (a) On and after the date on which the performance test... particulate matter in excess of 50 mg/dscm (0.022 gr/dscf)....

  9. 40 CFR 52.2059 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy: Particulate matter... Control strategy: Particulate matter. (a) Pennsylvania has committed to undertake a comprehensive program... Investigating and Controlling Nontraditional Particulate Matter Emissions Task Completion date Scheduled...

  10. 40 CFR 60.182 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.182... Smelters § 60.182 Standard for particulate matter. (a) On and after the date on which the performance test... furnace, or sintering machine discharge end any gases which contain particulate matter in excess of 50...

  11. 40 CFR 60.302 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.302... § 60.302 Standard for particulate matter. (a) On and after the 60th day of achieving the maximum... a grain dryer any process emission which: (1) Contains particulate matter in excess of 0.023...

  12. 40 CFR 60.52 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.52... § 60.52 Standard for particulate matter. (a) On and after the date on which the initial performance... atmosphere from any affected facility any gases which contain particulate matter in excess of 0.18 g/dscm...

  13. 40 CFR 52.2584 - Control strategy; Particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy; Particulate matter... Control strategy; Particulate matter. (a) Part D—Disapproval—USEPA disapproves Regulation NR 154.11(7)(b... control strategy to attain and maintain the standards for particulate matter, because it does not...

  14. 40 CFR 60.132 - Standard for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter. 60.132... and Bronze Production Plants § 60.132 Standard for particulate matter. (a) On and after the date on... reverberatory furnace any gases which: (1) Contain particulate matter in excess of 50 mg/dscm (0.022...

  15. 40 CFR 60.402 - Standard for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for particulate matter. 60.402... Plants § 60.402 Standard for particulate matter. (a) On and after the date on which the performance test... which: (i) Contain particulate matter in excess of 0.030 kilogram per megagram of phosphate rock feed...

  16. 40 CFR 60.52 - Standard for particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for particulate matter. 60.52... § 60.52 Standard for particulate matter. (a) On and after the date on which the initial performance... atmosphere from any affected facility any gases which contain particulate matter in excess of 0.18 g/dscm...

  17. 40 CFR 60.682 - Standard for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for particulate matter. 60.682... Insulation Manufacturing Plants § 60.682 Standard for particulate matter. On and after the date on which the... gases which contain particulate matter in excess of 5.5 kg/Mg (11.0 1b/ton) of glass pulled....

  18. 40 CFR 60.292 - Standards for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for particulate matter. 60... Manufacturing Plants § 60.292 Standards for particulate matter. (a) On and after the date on which the..., particulate matter at emission rates exceeding those specified in table CC-1, Column 2 and Column...

  19. 40 CFR 52.2059 - Control strategy: Particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy: Particulate matter... Control strategy: Particulate matter. (a) (b) EPA approves the PM-10 attainment demonstration for the...-Wilmington, PA-NJ-DE fine particulate matter (PM2.5) nonattainment area has attained the 2006 24-hour...

  20. High-Fidelity Micromechanics Model Enhanced for Multiphase Particulate Materials

    NASA Technical Reports Server (NTRS)

    Pindera, Marek-Jerzy; Arnold, Steven M.

    2003-01-01

    This 3-year effort involves the development of a comprehensive micromechanics model and a related computer code, capable of accurately estimating both the average response and the local stress and strain fields in the individual phases, assuming both elastic and inelastic behavior. During the first year (fiscal year 2001) of the investigation, a version of the model called the High-Fidelity Generalized Method of Cells (HFGMC) was successfully completed for the thermo-inelastic response of continuously reinforced multiphased materials with arbitrary periodic microstructures (refs. 1 and 2). The model s excellent predictive capability for both the macroscopic response and the microlevel stress and strain fields was demonstrated through comparison with exact analytical and finite element solutions. This year, HFGMC was further extended in two technologically significant ways. The first enhancement entailed the incorporation of fiber/matrix debonding capability into the two-dimensional version of HFGMC for modeling the response of unidirectionally reinforced composites such as titanium matrix composites, which exhibit poor fiber/matrix bond. Comparison with experimental data validated the model s predictive capability. The second enhancement entailed further generalization of HFGMC to three dimensions to enable modeling the response of particulate-reinforced (discontinuous) composites in the elastic material behavior domain. Next year, the three-dimensional version will be generalized to encompass inelastic effects due to plasticity, viscoplasticity, and damage, as well as coupled electromagnetothermomechanical (including piezoelectric) effects.