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Sample records for ferrite fine particles

  1. Subdomain zinc ferrite particles: Synthesis and characterization

    NASA Astrophysics Data System (ADS)

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

    1990-05-01

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

  2. Influence of particle size on the magnetic spectrum of NiCuZn ferrites for electromagnetic shielding applications

    NASA Astrophysics Data System (ADS)

    Wu, Xiaohan; Yan, Shuoqing; Liu, Weihu; Feng, Zekun; Chen, Yajie; Harris, Vincent G.

    2016-03-01

    The effect of ferrite particle size on the magnetic spectra (1 MHz to 1 GHz) of NiCuZn polycrystalline ferrites doped with Co2O3 and Bi2O3 were systematically investigated. The experiments indicate that the ferrite particle size tailored by grinding time and corresponding sintering temperatures is crucial to achieving high permeability, high Q-factor and low magnetic loss, at 13.56 MHz for electromagnetic shielding applications especially in the near field communication (NFC) field. It is evident that high-performance NiZnCu ferrite materials are strongly tailored by morphology and microstructure. It is conclusive that fine ferrite particles and relatively low sintering temperatures are favorable to lowering magnetic loss and enhancing permeability. This work has built a foundation for improvement of the ferrite slurry used for fabrication of large area tape-casting ferrite sheets.

  3. Effect of UV radiations to control particle size of Mn-Zn spinel ferrite nano-particles

    NASA Astrophysics Data System (ADS)

    Ameen Ramiza, F.; Ajmal, S. K.; Khan, M. B.; Nasim, A.; Jamil, Y.; Kashif, K.; Amira, S.

    2016-08-01

    MnxZn1-xFe2O4 (0.0 < x < 1.0) ferrite nano particles were synthesized for concentration varying from 0.27 to 0.87 to obtain chemically homogenous powder for obtaining fine particle size by co precipitation technique. Keeping in view the interest of scientists for particle size, the present work focus on the impact of UV radiation to control the particle size of prepared fine magnetic particles. The particles were digested for ninety minutes at a temperature of 90oC. The samples were divided into four equal quantities and were subjected to different doses of UV radiation. The chemically produced samples of Mn-Zn ferrite nano particles were analyzed by XRD which confirmed cubic spinel structure of the material. The average crystallite size (t), lattice parameter (a) and other structural parameters of UV-irradiated MnxZni-xFe2O4 spinel ferrite were calculated from XRD data. The spinel peak of the irradiated sample when compared with the control sample, shifted from 35.38 to 35.15. In few samples, additional peaks supporting the ferrite structure were also observed. The variation in the particle sizes observed for various doses of UV irradiation were in the range of 17.6 to 6.2 nm, whereas the particle size of the control was 8.82nm. The experiment was repeated for different concentrations, at the same digestion temperature and time revealed the similar results indicating that UV radiations can have a remarkable effect to control the phase and size of nano size fine magnetic ferrite particles. The present work successfully document the impact of UV to control the particle size.

  4. A study of the magnetic properties of cobalt ferrite-coated zinc ferrite particles

    NASA Astrophysics Data System (ADS)

    Tang, Huan; Du, You-wei; Qiu, Zi-qiang; Walker, J. C.

    1987-04-01

    Nearly spherical Zn0.2Fe2.8O4 particles coated with an epitaxial layer of CoFe2O4 ferrites of various thicknesses were studied with Mössbauer spectroscopy. Measurements reveal that the magnetic structures of these particles are different at room temperature and liquid nitrogen or liquid helium temperatures, indicating the existence of a Verwey transition, which occurs between 77 and 119 K. Coating of Co-ferrite has no sizable effect on the transition.

  5. Effect of MX type particles on creep strength of ferritic steel

    NASA Astrophysics Data System (ADS)

    Tamura, M.; Sakasegawa, H.; Kohyama, A.; Esaka, H.; Shinozuka, K.

    2003-09-01

    Creep rupture strength at 650 °C and microstructures of the plain ferritic steels with fine particles of the NaCl type (MX) were studied. Precipitation hardening by the fine MX type particles is more effective than solid solution hardening by tungsten. Excess precipitation of MX type particles relatively weakens the grain boundaries as compared with the matrix and, as a consequence, lowers the rupture strength. The equivalent obstacle spacing for mobile dislocations is calculated from the rupture data and is comparable to the interparticle distance observed by transmission electron microscopy. By controlling the interparticle distance of MX type particles with some adjustments of the chemical composition to meet the engineering requirements, it is feasible to develop a new alloy with high rupture strength at 650 °C which is superior to the conventional ferritic steels.

  6. Fine Particle Scrubbing: A Proceedings

    ERIC Educational Resources Information Center

    Journal of the Air Pollution Control Association, 1974

    1974-01-01

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

  7. Physical facets of ultrasonic cavitational synthesis of zinc ferrite particles.

    PubMed

    Reddy, Bhaskar Rao; Sivasankar, Thirugnanasambandam; Sivakumar, Manickam; Moholkar, Vijayanand S

    2010-02-01

    This paper addresses the physical features of the ultrasonic cavitational synthesis of zinc ferrite particles and tries to establish the relationship between cavitation physics and sonochemistry of the zinc ferrite synthesis. A dual approach of coupling experimental results with simulations of radial motion of cavitation bubbles has been adopted. The precursors for the zinc ferrite, viz. ZnO and Fe(3)O(4) are produced in situ by the hydrolysis of Zn and Fe(II) acetates stimulated by (*)OH radicals produced from the transient collapse of the cavitation bubbles. Experiments performed under different conditions create significant variation in the production of (*)OH radicals, and hence, the rate of acetate hydrolysis. Correlation of the results of experiments and simulations sheds light on the important facets of the physical mechanism of ultrasonic cavitational zinc ferrite synthesis. It is revealed that too much or too little rate of acetate hydrolysis results in smaller particle size of zinc ferrite. The first effect of a higher rate of hydrolysis leads to excessively large growth of particles, due to which they become susceptible to the disruptive action of cavitation bubbles. Whereas, the second effect of too small rate of hydrolysis of Zn and Fe(II) acetates restricts the growth of particles. It has been observed that the initial reactant concentration does not influence the mean particle size or the size distribution of zinc ferrite particles. The present investigation clearly confirms that the rate-controlling step of zinc ferrite synthesis through ultrasonic cavitational route is the rate of formation of (*)OH radicals from cavitation bubbles.

  8. Coating of zinc ferrite particles with a conducting polymer, polyaniline.

    PubMed

    Stejskal, Jaroslav; Trchová, Miroslava; Brodinová, Jitka; Kalenda, Petr; Fedorova, Svetlana V; Prokes, Jan; Zemek, Josef

    2006-06-01

    Particles of zinc ferrite, ZnOFe2O3, were coated with polyaniline (PANI) phosphate during the in situ polymerization of aniline in an aqueous solution of phosphoric acid. The PANI-ferrite composites were characterized by FTIR spectroscopy. X-ray photoelectron spectroscopy was used to determine the degree of coating with a conducting polymer. Even a low content of PANI, 1.4 wt%, resulted in the 45% coating of the particles' surface. On the other hand, even at high PANI content, the coating of ferrite surface did not exceeded 90%. This is explained by the clustering of hydrophobic aniline oligomers at the hydrophilic ferrite surface and the consequent irregular PANI coating. The conductivity increased from 2 x 10(-9) to 6.5 S cm(-1) with increasing fraction of PANI phosphate in the composite. The percolation threshold was located at 3-4 vol% of the conducting component. In the absence of any acid, a conducting product, 1.4 x 10(-2) Scm(-1), was also obtained. As the concentration of phosphoric acid increased to 3 M, the conductivity of the composites reached 1.8 S cm(-1) at 10-14 wt% of PANI. The ferrite alone can act as an oxidant for aniline; a product having a conductivity 0.11 S cm(-1) was obtained after a one-month immersion of ferrite in an acidic solution of aniline.

  9. Surface Structure of Nanometer-Sized Zinc Ferrite Particles by the Anomalous X-ray Scattering (AXS) Method

    NASA Astrophysics Data System (ADS)

    Matsubara, Eiichiro; Okuda, Kaneharu; Waseda, Yoshio; Saito, Toshihiko

    1992-10-01

    The atomic structure of nanometer-sized zinc ferrite particles has been studied with the anomalous x-ray scattering (AXS) method as well as the ordinary x-ray diffraction. The analysis of the peak broadening indicated that little microstrain exists in these nanometer-sized particles, and the average size of the particles is estimated to be 4 nm. Since the ratio of atoms located on the surface increases extremely in such fine particles, the contribution of these surface atoms to the x-ray scattering intensity was evaluated. The interference function Qi (Q) for the surface atoms appears to be similar to that of the zinc-ferrite glass. The experimental intensity is successfully explained by using a simple particle model consisting of the about 0.2 nm thick surface layer having a glass-like structure and the internal atoms having the ferrite crystalline structure.

  10. The effect of calcining temperature on the magnetic properties of the ultra-fine NiCuZn-ferrites

    SciTech Connect

    Kim, Jung-Sik Ham, Chang-Woo

    2009-03-05

    In this study, the ultra-fine NiCuZn-ferrite was prepared by a coprecipitation method. The magnetic properties were investigated in terms of calcining temperature. The ferrite powders, Ni{sub 0.206}Cu{sub 0.206}Zn{sub 0.618}Fe{sub 1.94}O{sub 4-{delta}}, were initially heat treated at various temperatures of 300-750 deg. C, and then sintered at the final temperature of 900 deg. C. The average particle size calculated by a XRD pattern and confirmed by a transmission electron microscope (TEM) micrograph was 7.5 nm. The calcining temperature was an important factor for microstructures and magnetic properties of the sintered ferrite. Scanning electron microscope (SEM) micrographs showed a uniform grain growth with small pores and high densification at the calcining temperature of 450 deg. C. From the results of magnetic property measurements, the ferrite calcined at 450 deg. C showed higher initial permeability (170) and quality factor (72) than those of other calcining temperatures.

  11. Fluidized-Bed Particles Scavenge Silicon Fines

    NASA Technical Reports Server (NTRS)

    Hsu, G. C.; Rohatgi, N.; Lutwack, R.; Hogle, R.

    1985-01-01

    Waste reduced, and silicon production rate improved. In new process silicon formed by thermal decomposition of SiH4. Part of silicon formed on silicon seed particles as result of surface chemical reaction. However, silicon formed by homogeneous reaction in gas phase tends to form aggregates of silicon atoms, which appear as fine particles (like dust). Believed that scavenging action of seed particles enables large fraction fines to be incorporated onto seed surface. This mode of growth confirmed by electron microscopy photographs.

  12. Development of porosity in an oxide dispersion strengthened ferritic alloy containing nanoscale oxide particles

    SciTech Connect

    Schneibel, Joachim H; Liu, Chain T; Hoelzer, David T; Mills, Michael J.; Sarosi, P. M.; Hayashi, Taisuke; Wendt, Ullrich; Heyse, Hartmut

    2007-01-01

    The development of porosity at 1000 C in an oxide dispersion strengthened ferritic alloy containing ultra-fine oxide particles with diameters on the order of a few nm is investigated. A comparison with an alloy fabricated by internal oxidation demonstrates that the porosity formation is associated with mechanical alloying with Y2O3 in argon. The pores grow in spite of a sub-micron grain size suggesting that the grain boundaries are not effective paths for removing entrapped gas from the pores.

  13. Microwave characterization of (Co,Zn) 2W barium hexagonal ferrite particles

    NASA Astrophysics Data System (ADS)

    Nie, Y.; He, H. H.; Feng, Z. K.; Zhang, X. C.; Cheng, X. M.

    2006-08-01

    This paper presents the static magnetic and microwave characterization of hexagonal ferrite BaZn 1.1Co 0.9Fe 16O 27 particles for application in a microwave absorber. The hexagonal ferrite particles have been developed through conventional ceramic processes. Ferrite particles were examined via scanning electron microscope, X-ray diffraction and vibrating sample magnetometry. The complex permeability and permittivity of ferrite-wax composites were measured over the frequency range of 2-8 GHz. The microwave intrinsic permeability and permittivity spectra have been presented, which were calculated on the basis of the measurement data of the ferrite-wax mixtures using the Bruggeman equation. The microwave absorption properties of these ferrite particles have also been discussed. The results indicate that these ferrites have good potential to be used as a broad band microwave absorber.

  14. Hydrothermal growth of fine magnetite and ferrite crystals

    NASA Astrophysics Data System (ADS)

    Byrappa, Shayan; Vicas, C. S.; Dhanaraj, Neel; Namratha, K.; Keerthana, S. D.; Dey, Ravi; Byrappa, K.

    2016-10-01

    In the present work, magnetite (Fe3O4, avg. 70 nm) synthesis employing Azadirachta indica (neem) leaf extract is reported originally using hydrothermal conditions and the results obtained were compared with that of D-glucose. Fourier transform infrared spectroscopy confirms the presence of polysaccharides and proteins in the extract which act as both surfactants and reducing agents, aided the formation of magnetite nanostructures. Authors also reported the selective doping of Zn, Cu and Co on nickel ferrite for the enhancement of adsorptive dye removal property, adopting and investigating the use of eloquent one-step green hydrothermal approach (T=180 °C, t=4 h, pH=12) with sodium dodecyl sulfate as surfactant. X-ray diffraction studies reveal that all the materials synthesized are isometric spinel structures and furthermore, morphological evidences using scanning electron microscopy are accounted. Adsorptive dye removal ability of synthesized materials was investigated using trypan blue as a probe. It was evident from the results that magnetite using neem extract showed enhanced adsorption ability (75%) than that of D-glucose (62%). Also, exponential increase in dye removal efficiency from 55% to 81% due to the presence of copper in nickel ferrite was duly noted.

  15. The influence of fine ferrite formation on the γ/α interface, fine bainite and retained austenite in a thermomechanically-processed transformation induced plasticity steel

    DOE PAGES

    Timokhina, Ilana B.; Miller, Michael K.; Beladi, Hossein; ...

    2016-03-03

    We subjected a Fe–0.26C–1.96Si–2Mn with 0.31Mo (wt%) steel to a novel thermomechanical processing route to produce fine ferrite with different volume fractions, bainite, and retained austenite. In two types of fine ferrites were found to be: (i) formed along prior austenite grain boundaries, and (ii) formed intragranularly in the interior of austenite grains. An increase in the volume fraction of fine ferrite led to the preferential formation of blocky retained austenite with low stability, and to a decrease in the volume fraction of bainite with stable layers of retained austenite. Moreover, the difference in the morphology of the bainitic ferritemore » and the retained austenite after different isothermal ferrite times was found to be responsible for the deterioration of the mechanical properties. The segregation of Mn, Mo, and C at distances of 2–2.5 nm from the ferrite and retained austenite/martensite interface on the retained austenite/martensite site was observed after 2700 s of isothermal hold. Finally, it was suggested that the segregation occurred during the austenite-to-ferrite transformation, and that this would decrease the interface mobility, which affects the austenite-to-ferrite transformation and ferrite grain size.« less

  16. Mechanical properties of 15%Mn steel with fine lamellar structure consisting of ferrite and austenite phases

    NASA Astrophysics Data System (ADS)

    Ueji, R.; Okitsu, Y.; Nakamura, T.; Takagi, Y.; Tanaka, Y.

    2010-07-01

    New steel with fine lamellar structure consisting of austenite and ferrite was developed. 15mass%Mn-3%Al-3%Si steel sheet was used in this study. First of all, the effect of the cooling rate on the microstructure was examined. The cooling at the slower speed of 100 deg/hour created the dual phase structure consisting of both austenite and ferrite. The additional rolling developed the fine lamellar duplex structure. Improvement of both the tensile strength and elongation was achieved by rolling. The strength increases furthermore by the rolling up to larger reduction. The 90% rolled sheet shows high tensile strength around 1000MPa with large elongation (15%-20%). These results indicate that the multi-phased structure with controlled lamellar morphology is beneficial for the management of both high strength and large ductility.

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

    NASA Astrophysics Data System (ADS)

    Totsuji, Hiroo

    2017-03-01

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

  18. Synthesis of Strontium Ferrite Ultrafine Particles Using Microemulsion Processing.

    PubMed

    Chen, Dong-Hwang; Chen, Yuh-Yuh

    2001-04-01

    The strontium ferrite ultrafine particles have been prepared using the microemulsion processing. The mixed hydroxide precursor was obtained via the coprecipitation of Sr(2+) and Fe(3+) in a water-in-oil microemulsion of water/CTAB/n-butanol/isooctane. According to the investigation on the thermochemical properties by TGA/DTA and the phase analysis by XRD, it was shown that the precursor could yield pure strontium ferrite after calcination at 700 degrees C for 5 h while using an appropriate molar ratio of Sr/Fe in microemulsions. From TEM measurement, the diameters of the precursor and calcined particles were 3.8+/-0.7 and 50-100 nm, respectively. The magnetic properties characterized by a SQUID magnetometer showed that the saturation magnetization, remanent magnetization, coercivity, and squareness ratio were 55 emu/g, 28 emu/g, 492 Oe, and 0.51, respectively. The magnetization was also observed to increase with the decrease of temperature at 5-400 K. Compared with those reported earlier, the quite low coercivity implies the potential application of final product in the high-density perpendicular recording media. Copyright 2001 Academic Press.

  19. Extended X-ray absorption fine structural studies of copper and nickel ferrites

    NASA Astrophysics Data System (ADS)

    Malviya, P. K.; Sharma, P.; Mishra, Ashutosh; Bhalse, D.

    2014-09-01

    The Cu-Ni ferrites with general formula Cu1-xNix Fe2O4 (where x=0.0, 0.05, 0.10, 0. 15, 0.20) were prepared by solid state root method. X-ray, K- absorption fine structural measurements were carried out. EXAFS spectra have been recorded at the K-edge of Fe using the dispersive EXAFS (DEXAFS) beam line at 2.5GeV Indus-2 synchrotron radiation source RRCAT, Indore, India. The EXAFS data have been analysed using the computer software Athena. These have been used to determine the bond lengths in these ferrites with the help of four different methods, namely, Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods.

  20. The many measures of fine particles

    SciTech Connect

    Kaye, B.H.; Trottier, R.

    1995-04-01

    Particle size is a critical parameter for a variety of operations in the chemical process industries (CPI). For example, the flow characteristics of granular materials, the sintering behavior of metallurgical powders, and the combustion efficiency of powdered coal are influenced to a major extent by particle size. The big push in the ceramics industry today is toward processing of powders at or below the one-micrometer level because use of such fine-grained materials allows tighter control of product properties. Accurate measurement or estimation of particle size is important because the quality and performance of most powder-based products are closely related to the size distribution of the fine particles. The electro-optic data processing revolution has spawned a new generation of particle-characterization equipment based on laser probing of particles systems. Computer-aided analysis of the data has come to play a dominant role. The paper discusses the critical step of sampling, the use of sieving for larger particles, the significance of particle shape, the use of lasers in size classifiers, particle surface properties, permeability techniques, and the need for instrument calibration.

  1. Influence of particle size on H2 and H2S sensing characteristics of nanocrystalline zinc ferrite

    NASA Astrophysics Data System (ADS)

    Ghosh, P.; Das, M. R.; Mitra, P.

    2016-12-01

    Nanocrystalline zinc ferrite ZnFe2O4 was synthesized by sol-gel self-combustion technique. Ball milling at room temperature was carried out to control the particle size. Characterization of synthesized powders was made using X-ray diffraction and transmission electron microscopy analysis. Fine powders resulted from milling were used to prepare gas sensing elements in pellet form. The gas-sensing properties were studied in presence of hydrogen and hydrogen sulphide as test gases. The gas response behavior was found to be strongly influenced by the particle size. Significantly high sensitivity of 82 % was found for 7 nm zinc ferrite in presence of 200 ppm H2S at an operating temperature of 150 °C. Sensitivity was found to increase with temperature before being maximum at a particular operating temperature.

  2. Magnetization anomalies of nanosize zinc ferrite particles prepared using electrodeposition

    NASA Astrophysics Data System (ADS)

    Roy, M. K.; Verma, H. C.

    2006-11-01

    Nanosize zinc ferrite particles have been prepared for the first time using electrodeposition. Zinc and iron are deposited on the cathode from a common bath containing the salts of zinc and iron. The deposited materials were forced to undergo electrochemical oxidation in a strong alkaline solution (1 M KOH) to convert them into oxides. Crystallization in ZnFe 2O 4 structure was obtained by heating the deposited material at appropriate temperature. X-ray diffraction pattern confirmed that the procedure leads to the formation of pure phase of ZnFe 2O 4. The magnetization value for the smallest size ZnFe 2O 4 is much smaller than that for the ZnFe 2O 4 made by most of the other methods although it shows a nice hysteresis shape. The magnetization shows very little variation with size in the range studied.

  3. Computer Models Simulate Fine Particle Dispersion

    NASA Technical Reports Server (NTRS)

    2010-01-01

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

  4. Hydrothermal synthesis of fine stabilized superparamagnetic nanoparticles of Zn2+ substituted manganese ferrite

    NASA Astrophysics Data System (ADS)

    Zahraei, Maryam; Monshi, Ahmad; Morales, Maria del Puerto; Shahbazi-Gahrouei, Daryoush; Amirnasr, Mehdi; Behdadfar, Behshid

    2015-11-01

    Superparamagnetic Zn2+ substituted manganese ferrite Mn1-xZnxFe2O4 (x=0.3, 0.35, 0.4 and 0.45) nanoparticles (NPs) were synthesized via a direct, efficient and environmental friendly hydrothermal method. The synthesized NPs were characterized by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and vibrating sample magnetometry (VSM). The effects of various parameters such as the pH of reaction mixture, time and temperature of hydrothermal treatment and Zn substitution on the spinel phase formation, the magnetization, and the size of resulting NPs are discussed. The Zn2+ substituted manganese ferrite NPs obtained from hydrothermal process crystallized mainly in the spinel phase. Nevertheless, without citrate ions, the hematite phase appeared in the product. The monophase Zn2+ substituted manganese ferrite NPs hydrothermally prepared in the presence of citric acid had mean particle size of 7 nm and a narrow size distribution. Furthermore, the synthesized NPs can be used to prepare ferrofluids for biomedical applications due to their small size, good stability in aqueous medium (pH 7) and also high magnetization value.

  5. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing. 5 refs., 1 tab.

  6. Settling classes for fine suspended particles

    NASA Astrophysics Data System (ADS)

    Brach-Papa, Christophe; Boyer, Patrick; Ternat, Fabien; Amielh, Muriel; Anselmet, Fabien

    2006-08-01

    The modelling of pollutant transfer in freshwater systems can be refined by considering the heterogeneities of the sedimentary dynamics and of the chemical reactivities of fine suspended particles. One of the first steps is the fractionation of these fine particles into effective settling classes. Although several methods exist, most of them are based on either granulometric considerations and/or arbitrary threshold criteria. This article presents the bases of an experimental method focusing on the direct measurement of the settling velocities without considering the granulometry and/nor any threshold criteria. The experimental work consists in recording the temporal evolution of the vertical distribution of the suspended solid concentration in a settling tank. A mathematical analysis provides the number of particle groups, and the mass contribution and the settling velocity for each This procedure is described and applied for validation, as a first step, to calibrated suspensions. Additional work is needed for a further analysis of the physical constraints involved in the model, as well as for more extensive experimental validation. To cite this article: C. Brach-Papa et al., C. R. Mecanique 334 (2006).

  7. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  8. Physics of compaction of fine cohesive particles.

    PubMed

    Castellanos, A; Valverde, J M; Quintanilla, M A S

    2005-02-25

    Fluidized fractal clusters of fine particles display critical-like dynamics at the jamming transition, characterized by a power law relating consolidation stress with volume fraction increment [sigma--(c) proportional, variant(Deltaphi)(beta)]. At a critical stress clusters are disrupted and there is a crossover to a logarithmic law (Deltaphi = nu logsigma--(c)) resembling the phenomenology of soils. We measure lambda identical with- partial differentialDelta(1/phi)/ partial log(sigma--(c) proportional, variant Bo(0.2)(g), where Bo(g) is the ratio of interparticle attractive force (in the fluidlike regime) to particle weight. This law suggests that compaction is ruled by the internal packing structure of the jammed clusters at nearly zero consolidation.

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  11. Probing fine magnetic particles with neutron scattering

    SciTech Connect

    Pynn, R.

    1991-12-31

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

  12. Probing fine magnetic particles with neutron scattering

    SciTech Connect

    Pynn, R.

    1991-01-01

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

  13. Temperature dependence of magnetic behaviour in very fine grained, spark plasma sintered NiCuZn ferrites

    SciTech Connect

    Ahmadi, Behzad; Zehani, Karim; LoBue, Martino; Loyau, Vincent; Mazaleyrat, Frederic

    2012-04-01

    Recently, using spark plasma sintering technique, a family of very fine grained, fully dense NiCuZn ferrites have been produced, which show constant permeability up to several 10 MHz. These ferrites can be used for filtering purposes in high frequency applications where a wide frequency band is required. In this paper, we study the magnetization processes taking place in these nano grained materials, in the frequency interval of 100 kHz to 5 MHz. Using a fluxmetric hysteresis graph, permeability, loss, and BH loops are measured at different temperatures, from -5 deg. C to 110 deg. C. Results are compared to the behavior of micrometric grain size ferrites, which are commonly used for power electronic and high frequency applications.

  14. Isolation of genomic DNA using magnetic cobalt ferrite and silica particles.

    PubMed

    Prodelalová, Jana; Rittich, Bohuslav; Spanová, Alena; Petrová, Katerina; Benes, Milan J

    2004-11-12

    Adsorption separation techniques as an alternative to laborious traditional methods (e.g., based on phenol extraction procedure) have been applied for DNA purification. In this work we used two types of particles: silica and cobalt ferrite (unmodified or modified with a reagent containing weakly basic aminoethyl groups, aminophenyl groups, or alginic acid). DNA from chicken erythrocytes and DNA isolated from bacteria Lactococcus lactis were used for testing of adsorption/desorption properties of particles. The cobalt ferrite particles modified with different reagents were used for isolation of PCR-ready bacterial DNA from different dairy products.

  15. Ordering of Fine Particles in a Planar Magnetron Plasma

    SciTech Connect

    Hayashi, Y.; Takahashi, K.; Totsuji, H.; Ishihara, O.; Sato, N.; Watanabe, Y.; Adachi, S.

    2008-09-07

    Fine particles injected in a planar magnetron were pushed upward by diffusible plasma, leading to being suspended by the force balance with the gravity and forming three-dimensional structures on the two-dimensional structure formed by particle strings.

  16. Innovations in the flotation of fine and coarse particles

    NASA Astrophysics Data System (ADS)

    Fornasiero, D.; Filippov, L. O.

    2017-07-01

    Research on the mechanisms of particle-bubble interaction has provided valuable information on how to improve the flotation of fine (<20 µm) and coarse particles (>100 µm) with novel flotation machines which provide higher collision and attachment efficiencies of fine particles with bubbles and lower detachment of the coarse particles. Also, new grinding methods and technologies have reduced energy consumption in mining and produced better mineral liberation and therefore flotation performance.

  17. Nanocrystalline nickel ferrite particles synthesized by non-hydrolytic sol-gel method and their composite with biodegradable polymer.

    PubMed

    Yin, H; Casey, P S; Chow, G M

    2012-11-01

    Targeted drug delivery has been one of the most important biomedical applications for magnetic particles. Such applications require magnetic particles to have functionalized surfaces/surface coatings that facilitate their incorporation into a polymer matrix to produce a polymer composite. In this paper, nanocrystalline nickel ferrite particles with an oleic acid surface coating were synthesized using a non-hydrolytic sol-gel method and incorporated into a biodegradable polymer matrix, poly(D,L-lactide) PLA prepared using a double emulsion method. As-synthesized nickel ferrite particles had a multi-crystalline structure with chemically adsorbed oleic acid on their surface. After forming the PLA composite, nickel ferrite particles were encapsulated in PLA microspheres. At low nickel ferrite concentrations, composites showed very similar surface charges to that of PLA. The composites were magnetically responsive and increasing the nickel ferrite concentration was found to increase magnetization of the composite.

  18. Process for recovering fine coal particles from slurry of finely divided coal

    SciTech Connect

    Harada, K.; Ogino, E.; Yoshii, N.

    1982-08-24

    Fine coal particles are recovered from a slurry of finely divided coal by mixing coarsely divided coal and a binder together to cause the binder to adhere to the surfaces of the coarsely divided coal pieces, mixing the slurry with the coal pieces having the binder adhered thereto to cause fine coal particles to adhere to the binder over the surfaces of the coal pieces serving as nuclei and thereby form agglomerates, and separating the agglomerates from the remaining slurry portion to recover the fine coal particles along with the coarsely divided coal and the binder.

  19. NASAL FILTERING OF FINE PARTICLES IN CHILDREN VS. ADULTS

    EPA Science Inventory

    Nasal efficiency for removing fine particles may be affected by developmental changes in nasal structure associated with age. In healthy Caucasian children (age 6-13, n=17) and adults (age 18-28, n=11) we measured the fractional deposition (DF) of fine particles (1 and 2um MMAD)...

  20. CHAMBER SIMULATION OF FINE PARTICLE PENETRATION INTO HOUSES

    EPA Science Inventory

    the paper discusses chamber simulation of fine particle penetration into houses. (NOTE: A number of recent studies have shown a correlation of negative health effects with increases in outdoor fine particles. Since people spend up to 90% of their time indoors, the relationship be...

  1. NASAL FILTERING OF FINE PARTICLES IN CHILDREN VS. ADULTS

    EPA Science Inventory

    Nasal efficiency for removing fine particles may be affected by developmental changes in nasal structure associated with age. In healthy Caucasian children (age 6-13, n=17) and adults (age 18-28, n=11) we measured the fractional deposition (DF) of fine particles (1 and 2um MMAD)...

  2. Effect of ferrite powder fineness on the structure and properties of ceramic materials

    SciTech Connect

    Pashchenko, V.P.; Nesterov, A.M.; Litvinova, O.G.

    1995-03-01

    Comprehensive study of the structure and properties of ferrite materials prepared from powders with different specific surface (0.4 M{sup 2}/g < S{sub sp} < 1.2 m{sub 2/g}) shows that the optimum specific surface of manganese-zinc ferrite powders is about 0.6 m{sup 2}1/g. With an increase in the specific surface of nickel-zinc and barium ferrite powders the porous crystalline structure of sintered specimens and most of the main electromagnetic properties of ferrite articles are improved.

  3. Structure and magnetic properties of Zn-Ti-substituted Ba-ferrite particles for magnetic recording

    NASA Astrophysics Data System (ADS)

    Wang, C. S.; Wei, F. L.; Lu, M.; Han, D. H.; Yang, Z.

    1998-03-01

    The formation process of Zn-Ti-doped Ba-ferrite particles was investigated by the X-ray diffraction technique, transmission electron microscope and magnetic measurements. The effects of heating temperature Th and the Zn-Ti substitution x on the microstructure and magnetic properties of BaFe 12-2 xZn xTi x O 19 particles with x=0.10-0.80 were studied. The temperature dependence of magnetic properties of these particles was measured.

  4. A facile microwave synthetic route for ferrite nanoparticles with direct impact in magnetic particle hyperthermia.

    PubMed

    Makridis, A; Chatzitheodorou, I; Topouridou, K; Yavropoulou, M P; Angelakeris, M; Dendrinou-Samara, C

    2016-06-01

    The application of ferrite magnetic nanoparticles (MNPs) in medicine finds its rapidly developing emphasis on heating mediators for magnetic hyperthermia, the ever-promising "fourth leg" of cancer treatment. Usage of MNPs depends largely on the preparation processes to select optimal conditions and effective routes to finely tailor MNPs. Microwave heating, instead of conventional heating offers nanocrystals at significantly enhanced rate and yield. In this work, a facile mass-production microwave hydrothermal synthetic approach was used to synthesize stable ferromagnetic manganese and cobalt ferrite nanoparticles with sizes smaller than 14 nm from metal acetylacetonates in the presence of octadecylamine. Prolonging the reaction time from 15 to 60 min, led to ferrites with improved crystallinity while the sizes are slight increased. The high crystallinity magnetic nanoparticles showed exceptional magnetic heating parameters. In vitro application was performed using the human osteosarcoma cell line Saos-2 incubated with manganese ferrite nanoparticles. Hyperthermia applied in a two cycle process, while AC magnetic field remained on until the upper limit of 45 °C was achieved. The comparative results of the AC hyperthermia efficiency of ferrite nanoparticles in combination with the in vitro study coincide with the magnetic features and their tunability may be further exploited for AC magnetic hyperthermia driven applications.

  5. Helical-mode magnetostatic resonances in small ferrite particles and singular metamaterials.

    PubMed

    Kamenetskii, E O

    2010-12-08

    Small ferrite-disk particles with magnetostatic (magneto-dipole) oscillations are characterized by the topological-phase states-the vortex states. In a recently published paper (Kamenetskii et al 2010 Phys. Rev. A 81 053823), it was shown that such magnetic vortices act as traps, providing purely subwavelength confinement of electromagnetic fields. The symmetry properties of magnetostatic-vortex ferrite disks allow one to propose new-type subwavelength microwave structures. In this paper it is demonstrated that the unique topological properties of the fields in a ferrite disk are intimately related to the symmetry breaking effects of magnetostatic oscillations. This analysis is based on postulates about a physical meaning of the magnetostatic-potential function ψ(r, t) as a complex scalar wavefunction, which presumes a long-range phase coherence in magnetic dipole-dipole interactions. The proper solutions are found based on an analysis of magnetostatic-wave propagation in a helical coordinate system. It is shown that while a composition of two helical waves may acquire a geometrical phase over-running of 2π during a period, every separate helical wave has a dynamical phase over-running of π and so behaves as a double-valued function. This results in the appearance of helical-mode magnetostatic resonances in quasi-2D ferrite disks. The solutions give magnetostatic-wave power-flow-density vortices with cores at the disk center and azimuthally running waves of magnetization. The near fields of magnetostatic-vortex ferrite-disk particles are characterized by space-time symmetry violation. For incident electromagnetic waves, such particles, with sizes much less than the free-space electromagnetic wavelength, appear as local singular regions. From the properties of a composition of magnetostatic-vortex ferrite-disk particles, one may propose novel metamaterials-singular metamaterials.

  6. Synthesis and properties of hybrid hydroxyapatite-ferrite (Fe3O4) particles for hyperthermia applications

    NASA Astrophysics Data System (ADS)

    Tkachenko, M. V.; Kamzin, A. S.

    2016-04-01

    Hybrid ceramics consisting of hydroxyapatite Ca10(PO4)6(OH)2 and ferrite Fe3O4 were synthesized using a two-stage procedure. The first stage included the synthesis of Fe3O4 ferrite particles by co-precipitation and the synthesis of hydroxyapatite. In the second stage, the magnetic hybrid hydroxyapatite-ferrite bioceramics were synthesized by a thorough mixing of the obtained powders of carbonated hydroxyapatite and Fe3O4 ferrite taken in a certain proportion, pressing into tablets, and annealing in a carbon dioxide atmosphere for 30 min at a temperature of 1200°C. The properties of the components and hybrid particles were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Mössbauer spectroscopy. The saturation magnetization of the hybrid ceramic composite containing 20 wt % Fe3O4 was found to be 12 emu/g. The hybrid hydroxyapatite (Ca10(PO4)6(OH)2)-ferrite Fe3O4 ceramics, which are promising for the use in magnetotransport and hyperthermia treatment, were synthesized and investigated for the first time.

  7. EDITORIAL: Cluster issue on fine particle magnetism

    NASA Astrophysics Data System (ADS)

    Fiorani, D.

    2008-07-01

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

  8. Evaluation of the resistance of DNA immobilized on ferrimagnetic particles of cobalt ferrite nanopowder against nuclease cleavage.

    PubMed

    Pershina, A G; Sazonov, A E; Ogorodova, L M

    2010-07-01

    DNA was immobilized on ferrimagnetic particles of cobalt ferrite nanopowder (CoFe(2)O(4)) and its resistance to endonuclease (DNase I) hydrolysis was studied. Immobilization on cobalt ferrite nanoparticles prevented enzymatic cleavage of DNA. This process was not associated with enzyme inactivation under the effect of nanosize cobalt ferrite and was presumably determined by lesser availability of the DNA molecule as a result of its interaction with nanoparticles.

  9. Cu multiply twinned particle precipitation in low-temperature fired Ni-Zn-Cu ferrite

    NASA Astrophysics Data System (ADS)

    Fujimoto, Masayuki; Hoshi, Ken-Ichi; Nakazawa, Mutsuo; Sekiguchi, Shoichi

    1993-12-01

    Cu metal precipitates and truncated Cu metal multiply twinned particles (MTPs) were observed in low-temperature fired ferrite with a small excess of Ni-Zn-Cu chemical composition. The Cu metal precipitates suggest the existence of Cu solid solution and accelerated grain growth during the sintering accompanied with the formation of defect structures, such as oxygen vacancies in the ferrite spinel structure. The defect structure compensation during the cooling process after sintering results in Cu metal precipitation at the multiple grain junction.

  10. Cu Multiply Twinned Particle Precipitation in Low-Temperature Fired Ni-Zn-Cu Ferrite

    NASA Astrophysics Data System (ADS)

    Fujimoto, Masayuki; Hoshi, Ken-ichi; Nakazawa, Mutsuo; Sekiguchi, Shoichi

    1993-12-01

    Cu metal precipitates and truncated Cu metal multiply twinned particles (MTPs) were observed in low-temperature fired ferrite with a small excess of Ni-Zn-Cu chemical composition. The Cu metal precipitates suggest the existence of Cu solid solution and accelerated grain growth during the sintering accompanied with the formation of defect structures, such as oxygen vacancies in the ferrite spinel structure. The defect structure compensation during the cooling process after sintering results in Cu metal precipitation at the multiple grain junction.

  11. Acoustic Agglomeration Process of Fine Particles in a Resonance Structure

    NASA Astrophysics Data System (ADS)

    Shi, Chen-hao; Zhang, Jian; Zhao, Yun; Liang, Jie

    2017-07-01

    It was proved that the acoustic agglomeration technology has a good application prospect in the removal of fine particles. In this paper, a removal system of acoustic agglomeration is constructed by the acoustic resonance structure. With the finite element simulation model, the effect and condition of sound pressure level (SPL) increment of high intensity sound in the resonance structure are defined. In the experiment, the contrast of the sampling weight and particle size distribution changes of fine particles was compared under different operating conditions to examine the effect of acoustic agglomeration on the removal efficiency of fine particles. The results show the SPL increment of 10dB is obtained with SPL 145-165 dB when the working frequency is changed from 400 to 2000 Hz. Under the action of acoustic agglomeration, fine particles in the aerosol were significantly reduced, and the removal effect is markedly improved with the increase of SPL.

  12. Anticorrosion Properties of Pigments based on Ferrite Coated Zinc Particles

    NASA Astrophysics Data System (ADS)

    Benda, P.; Kalendová, A.

    The paper deals with a new anticorrosion pigment, synthesized on a core-shell basis. For its syntheses a starting substance is used that forms the lamellar shaped core; namely lamellar zinc. The cover of the core is represented by zinc oxide, which is in fact partly oxidized lamellar zinc core, and is created during the calcination of the pigment. The compound that forms the top layer of the core, a ferrite, is also formed during calcination. The formula for the prepared pigment is then defined as MexZn1-xFe2O4/Zn and the formula of thin ferrite layer is MexZn1-xFe2O4 (where Me = Ca, Mg). Due to its shape, this anticorrosion pigment includes another anticorrosion effect, the so called "barrier effect". The mechanisms of anticorrosion effect, corrosion efficiency and mechanical properties were investigated for epoxy-ester paint systems with 10%pigment volume concentration (PVC). Mechanical tests were performed to determine the adhesiveness and mechanical resistance of paints and accelerated corrosion tests were carried out to evaluate efficiency against chemical degradation factors.

  13. PENETRATION OF AMBIENT FINE PARTICLES INTO THE INDOOR ENVIRONMENT

    EPA Science Inventory

    Several recent studies have indicated significant health risks associated with exposure to fine particles as measured outdoors. However, much of the exposure is believed to have occurred infdoors. consequently, there is considerable interest in the relationship between indoor a...

  14. Role of annealing in the structural and magnetic properties of Zn-Ferrite nano-particles

    NASA Astrophysics Data System (ADS)

    Ojha, Chaturbhuj; Shrivastava, A. K.

    2017-05-01

    For the present work, Zinc ferrite having compositional formula ZnFe2O4 have synthesized at room temperature through Chemical Co-Precipitation method. The precursors were annealed at different temperature 500, 700, and 900 °C. The structural and magnetic properties were investigated by XRD, SEM and VSM. X-ray diffraction pattern confirms the formation of cubic structure. Their corresponding reflection planes are also determined. The lattice constant calculated from XRD peaks is 8.39 A. Particle size calculated from XRD peak broadening confirms an average particles size of 12nm. Particles size measured using SEM show good agreement with the calculated value. Magnetization measurements have been carried on the nano-size Zn-ferrite and it was found that saturation Magnetization, Coercivity and Remanance were very lower compared to bulk materials. The saturation magnetization increases with increase in annealing temperature.

  15. Dispersion of fine phosphor particles by newly developed beads mill

    NASA Astrophysics Data System (ADS)

    Joni, I. Made; Panatarani, C.; Maulana, Dwindra W.

    2016-02-01

    Fine phosphor Y2O3:Eu3+ particles has advanced properties compare to conventional particles applied for compact fluorescent lamp (CFL) as three band phosphor. However, suspension of fine particles easily agglomerated during preparation of spray coating of the CFL tube. Therefore, it is introduced newly developed beads mill system to disperse fine phosphor. The beads mill consist of glass beads, dispersing chamber (impellers), separator chamber, slurry pump and motors. The first important performance of beads mill is the performance of the designed on separating the beads with the suspended fine particles. We report the development of beads mill and its separation performance vary in flow rate and separator rotation speeds. The 27 kg of glass beads with 30 µm in size was poured into dispersing chamber and then water was pumped continuously through the slurry pump. The samples for the separation test was obtained every 1 hours vary in rotation speed and slurry flow rate. The results shows that the separation performance was 99.99 % obtained for the rotation speed of >1000 rpm and flow rate of 8 L/minute. The performances of the system was verified by dispersing fine phosphor Y2O3:Eu3+ particles with concentration 1 wt.%. From the observed size distribution of particles after beads mill, it is concluded that the current design of bead mill effectively dispersed fine phosphor Y2O3:Eu3+.

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

    SciTech Connect

    Gohda, Takuma; Iizuka, Satoru

    2008-09-07

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

  17. Effect of annealing atmospheres on cobalt ferrite nono-particles and their applications

    NASA Astrophysics Data System (ADS)

    Kumar, V.; Pant, R. P.; Jain, V. K.; Yadav, M. S.

    2008-12-01

    Cobalt ferrite nano-particles have been synthesized by co-precipitation and annealed in air and in an inert atmosphere. Change in the physical properties has been analyzed by various analytical techniques like XRD, TEM, VSM, etc. A significant change in the physical properties like structural, particle shape, size, magnetization and microwave absorption has been observed. The effect of annealing on other properties like Curie temperature, electrical conductivity is also investigated. Particles unannealed and annealed in air and in an inert atmosphere are studied for electromagnetic wave interference. Tables 3, Figs 3, Refs 18.

  18. Inter-particle interactions and magnetism in manganese-zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Poddar, P.; Srikanth, H.; Morrison, S. A.; Carpenter, E. E.

    2005-03-01

    Manganese-zinc ferrite (Mn xZn 1-xFe 2O 4) nanoparticles were synthesized by reverse micelle technique using two different surfactant media—(1) bis-(2-ethylhexl) sodium sulfosuccinate (AOT) and (2) mix of nonylphenol poly(oxyethylene) 5 and nonylphenol poly(oxyethylene) 9 (NP) followed by annealing of precursors to remove the surfactant coating and to obtain better crystalline phase. A comparison of the magnetic properties showed distinct differences in blocking temperature, coercivity and saturation magnetization. Radio-frequency (RF) transverse susceptibility (TS) measurements were in agreement with the static magnetization data. Our precise TS measurements further revealed features associated with anisotropy fields that were dependent on the grain size, crystallinity and inter-particle interactions. Overall, we have demonstrated that RF TS is an excellent probe of the dynamic magnetization and influence of effects such as crystallinity and inter-particle interactions in soft ferrite nanoparticles.

  19. Particle size dependence of rotational responses in Ni-Zn ferrite

    NASA Astrophysics Data System (ADS)

    Anil Kumar, P. S.; Sainkar, S. R.; Shrotri, J. J.; Kulkarni, S. D.; Deshpande, C. E.; Date, S. K.

    1998-06-01

    Active powders of Ni-Zn ferrite were synthesized by soft chemical approaches and were processed with varying concentrations of Bi2O3. The sintered products were characterized extensively using a vibrating sample magnetometer, scanning electron microscopy, and resistivity techniques. The loss factor and the permeability have been evaluated. At an optimum concentration of Bi2O3 doping the loss factor has been reduced by 20%. The rotational responses are found to be strongly dependent on particle size.

  20. EFFECT OF BODY SIZE ON BREATHING PATTERN AND FINE PARTICLE DEPOSITION IN CHILDREN

    EPA Science Inventory

    Inter-child variability in breathing patterns may contribute to variability in fine particle, lung deposition and morbidity in children associated with those particles. Fractional deposition (DF) of fine particles (2um monodisperse, carnauba wax particles) was measured in healthy...

  1. EFFECT OF BODY SIZE ON BREATHING PATTERN AND FINE PARTICLE DEPOSITION IN CHILDREN

    EPA Science Inventory

    Inter-child variability in breathing patterns may contribute to variability in fine particle, lung deposition and morbidity in children associated with those particles. Fractional deposition (DF) of fine particles (2um monodisperse, carnauba wax particles) was measured in healthy...

  2. Experimental Study on Clogging of Fine Particles in Sand Sediments

    NASA Astrophysics Data System (ADS)

    Hirabayashi, S.

    2015-12-01

    In the methane hydrate development from the sand sediment beneath the seafloor, it is anticipated that the migrating fine particles may block the pore and consequently reduces the permeability near the production well. Although this phenomenon is known as skin formation, its microscopic mechanism is still unknown. As a part of a Japanese National hydrate research program (MH21, funded by METI), we carried out an experiment on the clogging of fine particles in sand sediments. A transparent core holder was newly developed to directly visualize the behavior of fine particles in the pore of frame sands and formation of skin. It was observed that there seems to be an induction time before the clogging starts to occur. Once clogging occurs, the upstream fine particles cannot move downstream anymore and the skin is formed. It was found that the rate of skin formation is related to the total volume of injected fine particles while the flow velocity has something to do with the length of the induction time.

  3. Atomic engineering of mixed ferrite and core-shell nanoparticles.

    PubMed

    Morrison, Shannon A; Cahill, Christopher L; Carpenter, Everett E; Calvin, Scott; Harris, Vincent G

    2005-09-01

    Nanoparticulate ferrites such as manganese zinc ferrite and nickel zinc ferrite hold great promise for advanced applications in power electronics. The use of these materials in current applications requires fine control over the nanoparticle size as well as size distribution to maximize their packing density. While there are several techniques for the synthesis of ferrite nanoparticles, reverse micelle techniques provide the greatest flexibility and control over size, crystallinity, and magnetic properties. Recipes for the synthesis of manganese zinc ferrite, nickel zinc ferrite, and an enhanced ferrite are presented along with analysis of the crystalline and magnetic properties. Comparisons are made on the quality of nanoparticles produced using different surfactant systems. The importance of various reaction conditions is explored with a discussion on the corresponding effects on the magnetic properties, particle morphology, stoichiometry, crystallinity, and phase purity.

  4. Fine particles and coarse particles: concentration relationships relevant to epidemiologic studies.

    PubMed

    Wilson, W E; Suh, H H

    1997-12-01

    Fine particles and coarse particles are defined in terms of the modal structure of particle size distributions typically observed in the atmosphere. Differences between the various modes are discussed. The fractions of fine and coarse particles collected in specific size ranges, such as total suspended particulate matter (TSP), PM10, PM2.5, and PM(10-2.5), are shown. Correlations of 24-h concentrations of PM2.5, PM10, and PM(10-2.5) at the same site show that, in Philadelphia and St. Louis, PM2.5 is highly correlated with PM10 but poorly correlated with PM (10-2.5). Among sites distributed across these urban areas, the site-to-site correlations of 24-h PM concentrations are high for PM2.5 but not for PM(10-2.5). This indicates that a PM measurement at a central monitor can serve as a better indicator of the community-wide concentration of fine particles than of coarse particles. The fraction of ambient outdoor particles found suspended indoors is greater for fine particles than for coarse particles because of the difference in indoor lifetimes. Consideration of these relationships leads to the hypothesis that the statistical associations found between daily PM indicators and health outcomes may be the result of variations in the fine particle component of the atmospheric aerosol, not of variations in the coarse component. As a result, epidemiologic studies using PM10 or TSP may provide more useful information on the acute health effects of fine particles than coarse particles. Fine and coarse particles are separate classes of pollutants and should be measured separately in research and epidemiologic studies. PM2.5 and PM(10-2.5) are indicators or surrogates, but not measurements, of fine and coarse particles.

  5. Enhanced electrical properties in Nd doped cobalt ferrite nano-particles

    NASA Astrophysics Data System (ADS)

    Abbas, S.; Munir, A.; Zahra, F.; Rehman, M. A.

    2016-08-01

    Spinel ferrites are important class of compounds which has variety of electrical, magnetic and catalytic applications. A small amount of rare earth element causes modification in structural, electrical and magnetic properties of ferrite materials for practical applications. Neodymium doped cobalt ferrites with composition CoNdxFe2-xO4 where x is 0.1 has been synthesized by sol-gel method. Sol-gel method was preferred because it has good control over stoichiometry, crystallite size and particle size distribution. Characterization was done by using X-Ray Diffraction (XRD) technique for structural analysis and crystal structure was found to be spinel. Particles like morphology was observed in micrographs obtained by Scanning Electron Microscopy (SEM). Thermal analysis of sample has been done which includes Thermogravimetric analysis (TGA) and Differential Scanning calorimetry (DSC). Fourier transform infra-red spectroscopy (FT-IR) of samples was also performed. DC resistivity as a function of temperature has been studied and its shows direct dependence on temperature and inverse dependence on the concentration of Nd dopant. The studied material is a potential candidate for resistive random access memory application.

  6. Control of Particle Size and Morphology of Cobalt-Ferrite Nanoparticles by Salt-Matrix during Annealing

    NASA Astrophysics Data System (ADS)

    Azizi, A.; Sadrnezhaad, S. K.; Mostafavi, M.

    Salt-matrix annealing of mechanically alloyed Co-ferrite nanopowder was used to modify its particle size and morphology. Efficiency improvement due to suppression of sintering and growth resulted in reduction of average particle size from 100nm for salt-less to 40nm for salt-full annealing procedure. Nanosized single-phase cobalt-ferrite particles were observed after 2h annealing at 750°C in the samples milled for 20 hours both with and without NaCl. NaCl:CoFe2O4 ratio of 10:1 resulted in cabbage-like clusters containing particles smaller than 50 nm.

  7. Role of copper on structural, magnetic and dielectric properties of nickel ferrite nano particles

    NASA Astrophysics Data System (ADS)

    Balavijayalakshmi, J.; Suriyanarayanan, N.; Jayaprakash, R.

    2015-07-01

    Copper doped nickel ferrites Ni(1-x)CuxFe2O4 (where x=0.2, 0.4, 0.6) nanoparticles are prepared by co-precipitation method and sintered at 600 °C. The XRD study confirms the formation of single-phase cubic spinel Ni-Cu ferrites. The particle size increases with Cu substitution. FT-IR spectra confirm the absorption bands around 554-547 cm-1 for the tetrahedral sites and around 448-450 cm-1 for the octahedral sites. The inclusion of copper shifts the tetrahedral band to lower values. The saturation magnetization (Ms) and remanent magnetization (Mr) decrease with increase in copper concentration and the coercivity (Hc) is found to increase for all the compositions sintered at 600 °C. The dielectric constant decreases drastically for all the compositions and reaches a constant value. These nanoparticles can be tested for humidity sensing applications.

  8. Mössbauer investigation of zinc ferrite particles

    NASA Astrophysics Data System (ADS)

    Tang, H.; Du, Y.-W.; Qiu, Z.-Q.; Walker, J. C.

    1988-04-01

    Mössbauer spectra of Zn0.2Fe2.3O4 particles at different temperatures have been obtained. They have been analyzed with five components, one due to the A-site Fe3+ ions, and the others due to the B-site Fe3+ and Fe2+ ions. Magnetic and electronic properties have been discussed with regard to zinc substitution and temperature dependence.

  9. Fine structure of auroral particle acceleration

    SciTech Connect

    Lynch, K.A.

    1992-01-01

    A mass-analyzing capped hemispherical electrostatic analyzer was developed for the purpose of resolving the mass, energy, and pitch angle distributions of auroral ions. The instrument, the B-field Hemispherical Electrostatic Energy and Pitch Angle Spectrometer (BEEPS), is an extension of the HEEPS instrument, which uses a hemispherical analyzer and microchannel plates to measure the angular and energy distribution of ions. BEEPS uses a toroidal magnetic field constructed from rare-earth permanent magnets to separate ion measurements into two groups, protons and heavier ions. BEEPS was flown in February, 1991, from Poker Flat, Alaska, on the TOPAZ3 sounding rocket. This sounding rocket mission carried a full array of particle and field instrumentation to an altitude of over 1000 km. Electron data from the flight are presented and discussed in detail, and are shown in light of both ion and wave data taken during the same flight. Correspondences between the various data sets are presented. Particular note is made of the observation that ion heating seems to correspond with a field-aligned plateau in the electron distribution function below the peak electron energy. The growth rate of the n = -1 anomalous Doppler resonance of medium energy electrons with lower hybrid waves is discussed, and proposed as a mechanism for converting energy from the auroral electrons, the driver of the auroral activity, to the ion heating events.

  10. Source contributions to atmospheric fine carbon particle concentrations

    NASA Astrophysics Data System (ADS)

    Andrew Gray, H.; Cass, Glen R.

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

  11. Autonomous patterning of cells on microstructured fine particles.

    PubMed

    Takeda, Iwori; Kawanabe, Masato; Kaneko, Arata

    2015-05-01

    Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5-40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Modification of electrostatic charge on inhaled carrier lactose particles by addition of fine particles.

    PubMed

    Bennett, F S; Carter, P A; Rowley, G; Dandiker, Y

    1999-01-01

    Triboelectrification affects particle adhesion and agglomeration and hence the formulation, manufacture, and use of dry powder inhaler (DPI) devices. Electrostatic charge measurement of two component mixes of spray-dried or crystalline lactose fine particles (< 10 microns) 0, 5, 10, 15, 20, and 30% w/w with spray-dried or crystalline lactose 63-90 microns, respectively, has been undertaken using a system incorporating pneumatic transport of the mixed powders to a stainless steel cyclone charging device. The magnitude of charge on the mixes was shown to decrease with increased fine particle content, and there was no significant difference in charge for each concentration between spray-dried and crystalline lactose. Both the variation of charge and powder adhesion to the cyclone surface increased with increase in fine particle content. The proportion of fine particles in carrier systems in DPIs may thus have an important role where triboelectrification is involved.

  13. Benthic biofilm controls on fine particle dynamics in streams

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  14. Benthic Biofilm Controls on Fine Particle Dynamics in Streams

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    Benthic (streambed) biofilms metabolize a substantial fraction of particulate organic matter and nutrient inputs to streams. These microbial communities comprise a significant proportion of overall biomass in headwater streams, and they present a primary control on the transformation and export of labile organic carbon. Biofilm growth has been linked to enhanced fine particle deposition and retention, a feedback that confers a distinct advantage for the acquisition and utilization of energy sources. We quantified the influence of biofilm structure on fine particle deposition and resuspension in experimental stream mesocosms. Biofilms were grown in identical 3-m recirculating flumes over periods of 18-47 days to obtain a range of biofilm characteristics. Fluorescent, 8-μm particles were introduced to each flume, and their concentrations in the water column were monitored over a 30-minute period. We measured particle concentrations using a flow cytometer and mesoscale (10 μm-1 cm) biofilm structure using optical coherence tomography. Particle deposition-resuspension dynamics were determined by fitting results to a stochastic mobile-immobile model, which showed retention timescales for particles within the biofilm-covered streambeds followed a power-law residence time distribution. Deposition rates were not affected by biofilm structure, while particle retention timescales were strongly influenced by areal biofilm coverage. Our findings suggest that exposed biofilm surface area may be a primary predictor of reach-scale particle retention.

  15. Fine particle migration and collection in a wet electrostatic precipitator.

    PubMed

    Yang, Zhengda; Zheng, Chenghang; Chang, Qianyun; Wan, Yi; Wang, Yi; Gao, Xiang; Cen, Kefa

    2017-04-01

    Electrostatic precipitation is considered as an effective technology for fine particle removal. A lab-scale wet electrostatic precipitator (ESP) with wire-to-plate configuration was developed to study particle migration and collection. The performance of the wet ESP was evaluated in terms of the corona discharge characteristics, total removal efficiency and fractional removal efficiency. The corona discharge characteristics and particle removal abilities of the wet ESP were investigated and compared with dry ESP. Particle removal efficiency was influenced by discharge electrode type, SO2 concentration, specific collection area (SCA) and particle/droplet interaction. Results showed that the particle removal efficiency of wet ESP was elevated to 97.86% from 93.75% of dry ESP. Three types of discharge electrodes were investigated. Higher particle removal efficiency and larger migration velocity could be obtained with fishbone electrode. Particle removal efficiency decreased by 2.87% when SO2 concentration increased from 0 ppm to 43 ppm as a result of the suppression of corona discharge and particle charging. The removal efficiency increased with higher SCA, but it changed by only 0.71% with the SCA increasing from 25.0 m(2)/(m(3)/s) to 32.5 m(2)/(m(3)/s). Meanwhile, the increasing of particle and droplet concentration was favorable to the particle aggregation and improved particle removal efficiency. This work tends to study the particle migration and collection under spraying condition. The performance of a wet electrostatic precipitator (ESP) is evaluated in terms of the corona discharge characteristics, total particle removal efficiency, and fractional particle removal efficiency. The effects of water droplets on particle removal, especially on removal of particles with different sizes, is investigated. The optimization work was done to determine appropriate water consumption, discharge electrode type, and specific collection area, which can provide a basis for wet

  16. Sizing fine particles with the phase Doppler interferometric technique

    NASA Astrophysics Data System (ADS)

    Sankar, S. V.; Weber, B. J.; Kamemoto, D. Y.; Bachalo, W. D.

    1991-11-01

    A systematic theoretical and experimental study was carried out to investigate the response characteristics of a phase Doppler particle analyzer (PDPA). The theoretical analysis used a model based on the Lorenz-Mie theory; in the experiments the PDPA was used to size fine polystyrene latex particles dispersed in water and in air. The experimental and theoretical results demonstrate that the magnitude of oscillations in the phase vs size calibration curves of the PDPA can be decreased by a proper choice of the optical configuration. Sizing of small particles (less than 10 microns) with a resolution of +/-0.3 to +/-0.4 micron is shown to be possible.

  17. Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

    PubMed Central

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    As one component of a study investigating the impact of vehicle emissions on near-road air quality, human exposures, and potential health effects, particles were measured from September 21 to October 30, 2010 on both sides of a major roadway (Interstate-96) in Detroit. Traffic moved freely on this 12 lane freeway with a mean velocity of 69 mi/hr. with little braking and acceleration. The UC Davis DELTA Group rotating drum (DRUM) impactors were used to collect particles in 8 size ranges at sites nominally 100 m south, 10 m north, 100 m north, and 300 m north of the highway. Ultra-fine particles were continuously collected at the 10 m north and 100 m north sites. Samples were analyzed every 3 h for mass (soft beta ray transmission), 42 elements (synchrotron-induced x-ray fluorescence) and optical attenuation (350-800 nm spectroscopy). A three day period of steady southerly winds along the array allowed direct measurement of freeway emission rates for coarse (10 > Dp > 1.0 μm), PM2.5, very fine (0.26 > Dp > 0.09 μm), and ultra-fine (Dp < 0.09 μm) particles. The PM2.5 mass concentrations were modeled using literature emission rates during the south to north wind periods, and averaged 1.6 ± 0.5 μg/m3, versus the measured value of 2.0 ± 0.7 μg/m3. Using European freeway emission rates from 2010, and modeling them at the I-96 site, we would predict roughly 3.1 μg/m3 of PM2.5 particles, corrected from the 4.9 PM10 value by their measured road dust contributions. Using California car and truck emission rates of 1973, this value would have been about 16 μg/m3, corrected down from the 19 μg/m3 PM5.0 using measured roadway dust contributions. This would have included 2.7 μg/m3 of lead, versus the 0.0033 μg/m3 measured. Very fine particles were distributed across the array with a relatively weak falloff versus distance. For the ultra-fine particles, emissions of soot and metals seen in vehicular braking studies correlated with traffic at the 10 m site, but only the

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

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

  20. Atmospheric PAH concentrations in fine and coarse particles.

    PubMed

    Vardar, Nedim; Noll, Kenneth E

    2003-09-01

    Measurements of the urban air concentrations of PAHs associated with PM2.5-fine and PM 10-coarse particles in Chicago on the campus of IIT were achieved using a Universal Air Sampler. Short sampling time (12 hr) and high flow rates were used to measure the PAH concentrations in fine and coarse particles. Measured ambient concentrations of PAHs were classified based on wind direction and back trajectory calculations as Land and Lake samples. Differences in ambient concentrations of PAHs were observed between Land and Lake samples. Fine particle concentrations varied from 9.5 to 25.7 ng m(-3) and averaged 18.2 ng m(-3) for the Land samples, while they ranged from 4.2 to 31.5 ng m(-3) and averaged 13.4 ng m(-3) for the Lake samples. The measured PAH concentrations in coarse particles varied from 6.2 to 22.1 ng m(-3) and averaged 12.9 ng m(-3) for the Land samples, and they ranged from 2.4 to 13.0 ng m(-3) with an average value of 7.3 ng m(-3) for the Lake samples. The fine/coarse ratio of each individual PAH compound varied between 1.3 and 2.7 for the Land samples: it varied between 1.6 and 4.2 for the Lake samples. There was an increase in the fine/coarse ratio of PAH as molecular weight of the compound increases for both Land and Lake samples.

  1. Biocompatible ferrite nanoparticles for hyperthermia: effect of polydispersity, anisotropy energy and inter-particle interaction

    NASA Astrophysics Data System (ADS)

    Wadehra, Neha; Gupta, Ruby; Prakash, Bhanu; Sharma, Deepika; Chakraverty, S.

    2017-02-01

    We have simulated the rise in temperature (ΔT) of uniaxial single domain nanomagnets (particle size r) placed under alternating (AC) magnetic field (frequency ω) in ‘r-ω’ plane. Based on this, a phase space of ‘ΔT max-r-ω’ has been constructed. This phase space suggests two bio-compatible ferrites namely Fe3O4 and MnFe2O4 which may generate necessary temperature for hyperthermia effect. Our simulated results further show that introduction of particle size distribution drastically reduces the efficiency of heat generation. On the other hand, introduction of inter-particle magnetic dipolar interactions may enhance the temperature rise.

  2. High intensity conditioning to improve flotation of gold fine particles

    SciTech Connect

    Valderrama, L.; Perez, C.; Rubio, J.

    1995-12-31

    This work describes the effect of the degree of energy transferred to the pulp, during the conditioning stage, on gold flotation fines recovery, grade and kinetics, with three types of frother (Dowfroth 250, pine oil and MIBC) and amyl xanthate as collector. Best results show an increase in 24% recovery and 50% in concentrate grade, depending on the intensity of conditioning and type of frother (better with Dowfroth 250). For low or intermediate energies (0.5--1.5 kWh/m3 pulp), the fine particles adhere to larger ones, increasing the recovery due to a mixture of carrier (pyrite, in this case) and autogeneous carrier flotation and at higher shear (2--3 kWh/m3 pulp), gold fine particles aggregate themselves. These phenomena are demonstrated by measurements of flotation rate, true flotation (flotation by actual particle-bubble adhesion), and by the amount of entrained particles. Alternatives for this type of pulp conditioning and mechanisms involved are discussed.

  3. Modeling of Fine-Particle Formation in Turbulent Flames

    NASA Astrophysics Data System (ADS)

    Raman, Venkat; Fox, Rodney O.

    2016-01-01

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

  4. Synthesis, structural, dielectric and magnetic properties of polyol assisted copper ferrite nano particles

    NASA Astrophysics Data System (ADS)

    Pavithradevi, S.; Suriyanarayanan, N.; Boobalan, T.

    2017-03-01

    Nanocrystalline copper ferrite CuFe2O4 is synthesized by co-precipitation method in ethylene glycol as chelating agent, using sodium Hydroxide as precipitator at pH 8. The as synthesized CuFe2O4 is annealed at temperatures of 350 °C, 700 °C, and 1050 °C for 2 h respectively. The thermal analysis of the synthesized sample is done by TG technique. It is shown that at 260 °C ethylene glycol has evaporated completely and after 715 °C, spinel ferrite is formed with a cubic structure. The calculated lattice parameters are in agreement with the reported values. FTIR spectra of CuFe2O4 nano particles are as synthesized and annealed at 1050 °C and recorded between 400 cm-1 and 4000 cm-1. It shows that when the temperature increases ethylene glycol gradually evaporates. Finally, nano crystalline single phase spinel ferrite is obtained. X-ray diffraction (XRD) and electron diffraction (EDS) studies show that the sample is indexed as the face centered cubic spinel structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that the particles are flaky and spherical with the crystallite size in the range of 25-34 nm. From the dielectric studies, the dielectric constant decreases as the frequency increases. Low value of dielectric loss at higher frequencies suggests that the material is suitable for high frequency applications. AC conductivity increases with frequency. The magnetic properties of the samples are measured using a vibrating sample magnetometer (VSM) at room temperature, which shows that the sample exhibited a typical super paramagnetic behavior at low temperature. The saturation magnetization, remanant magnetism, and coercivity increases with applied field.

  5. Microwave Assisted Synthesis of Ferrite Nanoparticles: Effect of Reaction Temperature on Particle Size and Magnetic Properties.

    PubMed

    Kalyani, S; Sangeetha, J; Philip, John

    2015-08-01

    The preparation of ferrite magnetic nanoparticles of different particle sizes by controlling the reaction temperature using microwave assisted synthesis is reported. The iron oxide nanoparticles synthesized at two different temperatures viz., 45 and 85 °C were characterized using techniques such as X-ray diffraction (XRD), small angle X-ray scattering (SAXS), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The average size of iron oxide nanoparticles synthesized at 45 and 85 °C is found to be 10 and 13.8 nm, respectively, and the nanoparticles exhibited superparamagantic behavior at room temperature. The saturation magnetization values of nanoparticles synthesized at 45 and 85 °C were found to be 67 and 72 emu/g, respectively. The increase in particle size and saturation magnetization values with increase in incubation temperature is attributed to a decrease in supersaturation at elevated temperature. The Curie temperature was found to be 561 and 566 0C for the iron oxide nanoparticles synthesized at 45 and 85 °C, respectively. The FTIR spectrum of the iron oxide nanoparticles synthesized at different temperatures exhibited the characteristic peaks that corresponded to the stretching of bonds between octahedral and tetrahedral metal ions to oxide ions. Our results showed that the ferrite nanoparticle size can be varied by controlling the reaction temperature inside a microwave reactor.

  6. Fine separation of particles via the entropic splitter

    NASA Astrophysics Data System (ADS)

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

    2017-08-01

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

  7. Urban heat island impacted by fine particles in Nanjing, China.

    PubMed

    Wu, Hao; Wang, Tijian; Riemer, Nicole; Chen, Pulong; Li, Mengmeng; Li, Shu

    2017-09-12

    Atmospheric aerosol particles (especially particles with aerodynamic diameters equal to or less than 2.5 μm, called PM2.5) can affect the surface energy balance and atmospheric heating rates and thus may impact the intensity of urban heat islands. In this paper, the effect of fine particles on the urban heat island intensity in Nanjing was investigated via the analysis of observational data and numerical modelling. The observations showed that higher PM2.5 concentrations over the urban area corresponded to lower urban heat island (UHI) intensities, especially during the day. Under heavily polluted conditions, the UHI intensity was reduced by up to 1 K. The numerical simulation results confirmed the weakening of the UHI intensity due to PM2.5 via the higher PM2.5 concentrations present in the urban region than those in the suburban areas. The effects of the fine particles on the UHI reduction were limited to the lowest 500-1000 m. The daily range of the surface air temperature was also reduced by up to 1.1 K due to the particles' radiative effects. In summary, PM2.5 noticeably impacts UHI intensity, which should be considered in future studies on air pollution and urban climates.

  8. Preparation and magnetic properties of nano size nickel ferrite particles using hydrothermal method

    PubMed Central

    2012-01-01

    Background Nickel ferrite, a kind of soft magnetic materials is one of the most attracting class of materials due to its interesting and important properties and has many technical applications, such as in catalysis, sensors and so on. In this paper the synthesis of NiFe2O4 nanoparticles by the hydrothermal method is reported and the inhibition of surfactant (Glycerol or Sodium dodecyl sulfate) on the particles growth is investigated. Methods For investigation of the inhibition effect of surfactant on NiFe2O4 particles growth, the samples were prepared in presence of Glycerol and Sodium dodecyl sulfate. The X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM) and inductively coupled plasma atomic emission spectrometer (ICP-AES) techniques were used to characterize the samples. Results The results of XRD and ICP-AES show that the products were pure NiFe2O4 and also nanoparticles grow with increasing the temperature, while surfactant prevents the particle growth under the same condition. The average particle size was determined from the Scherrer's equation and TEM micrographs and found to be in the range of 50-60 nm that decreased up to 10-15 nm in presence of surfactant. The FT-IR results show two absorption bands near to 603 and 490 cm-1 for the tetrahedral and octahedral sites respectively. Furthermore, the saturated magnetization and coercivity of NiFe2O4 nanoparticles were in the range of 39.60 emu/g and 15.67 Qe that decreased for samples prepared in presence of surfactant. As well as, the nanoparticles exhibited a superparamagnetic behavior at room temperature. Conclusions Nanosized nickel ferrite particles were synthesized with and without surfactant assisted hydrothermal methods. The results show that with increasing of temperature, the crystallinity of nanoparticles is increased. In the presence of surfactants, the crystallinity of NiFe2O4 nanoparticles

  9. Zinc doped copper ferrite particles as temperature sensors for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Hankiewicz, Janusz H.; Alghamdi, Noweir; Hammelev, Nicholas M.; Anderson, Nick R.; Camley, Robert E.; Stupic, Karl; Przybylski, Marek; Zukrowski, Jan; Celinski, Zbigniew J.

    2017-05-01

    We investigate the use of Cu0.35Zn0.65Fe2O4 particles as temperature-dependent sensors in magnetic resonance imaging (MRI). This material has a Curie temperature near 290 K, but in the large magnetic fields found in MRI scanners, there is a significant temperature-dependent magnetic moment near body temperature; 310 K. When the ferrite particles are doped into an agar gel, the temperature-dependent magnetic moment leads to a temperature-dependent broadening of the NMR linewidth for water protons and to a temperature-dependent image intensity for MRI, allowing one to make temperature maps within objects. The temperature resolution is about 1.3 K.

  10. Structural, electrical and magnetic characteristics of nickel substituted cobalt ferrite nano particles, synthesized by self combustion method

    NASA Astrophysics Data System (ADS)

    Sontu, Uday Bhasker; Yelasani, Vijayakumar; Musugu, Venkata Ramana Reddy

    2015-01-01

    Nickel-substituted cobalt ferrite nano-particles are synthesized using a self-combustion method. Aqueous metal nitrates and citric acid form the precursors. No external oxidizing agents are used to change the pH of the precursors; this resulted in a more environment friendly synthesis. Structural, magnetic and electrical characteristics of the nano ferrites are verified using X-ray diffractometer (XRD), VSM and impedance analyzer respectively. Phase formation, particle size, lattice parameter, X-ray density, saturation magnetization, coercivity, dielectric constant and electrical activation energy as function of nickel substitution in cobalt ferrite are studied. It is shown here that the magnetic and electrical properties can be tuned by varying the nickel concentration.

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

    PubMed

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

    2014-08-01

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

  12. CHARACTERIZING THE SOURCES OF HUMAN EXPOSURE TO MUTAGENIC AND CARCINOGENIC CHEMICALS IN AIRBORNE FINE PARTICLES

    EPA Science Inventory

    Personal and ambient exposures to airborne fine particles, polycyclic aromatic hydrocarbons (PAH), and genotoxic activity has been studied in populations in the US, Japan, China, and the Czech Republic. Personal exposure monitors used to collect fine particles were extracted f...

  13. Synthesis of Single-Walled Carbon Nanotubes in a Glow Discharge Fine Particle Plasma

    SciTech Connect

    Imazato, N.; Imano, M.; Hayashi, Y.

    2008-09-07

    Carbon fine particles were synthesized being negatively charged and confined in a glow discharge plasma. The deposited fine particles were analyzed by Raman spectroscopy and transmission electron microscopy (TEM) and were confirmed to include single-walled carbon nanotubes.

  14. CHARACTERIZING THE SOURCES OF HUMAN EXPOSURE TO MUTAGENIC AND CARCINOGENIC CHEMICALS IN AIRBORNE FINE PARTICLES

    EPA Science Inventory

    Personal and ambient exposures to airborne fine particles, polycyclic aromatic hydrocarbons (PAH), and genotoxic activity has been studied in populations in the US, Japan, China, and the Czech Republic. Personal exposure monitors used to collect fine particles were extracted f...

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

    PubMed

    Aoyagi, Hideki; Ugwu, Charles U

    2011-01-01

    Adhesion of commercially produced fullerene fine particles to Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica pollen grains was investigated. The autofluorescence of pollen grains was affected by the adhesion of fullerene fine particles to the pollen grains. The degree of adhesion of fullerene fine particles to the pollen grains varied depending on the type of fullerene. Furthermore, germination of Camellia japonica pollen grains was inhibited by the adhesion of fullerene fine particles.

  16. Formation of nano-size oxide particles and δ-ferrite at elevated temperature in 9Cr-ODS steel

    NASA Astrophysics Data System (ADS)

    Kim, Sawoong; Ohtsuka, Satoshi; Kaito, Takeji; Yamashita, Shinichiro; Inoue, Masaki; Asayama, Tai; Shobu, Takahisa

    2011-10-01

    Excellent high-temperature strength and resistance to radiation damage of 9Cr Oxide Dispersion Strengthened (9Cr-ODS) martensitic steel have been realized by nano-size Y-Ti-O complex oxide particles dispersed in the matrix and a dual phase structure consisting of α'-martensite and δ-ferrite. These are produced by mechanically alloying Fe-Cr-Ti powders with Y 2O 3 followed by a hot-consolidation process. Therefore, the hot-consolidation process is the issue to be clarified for the formation of nano-size oxide particle and δ-ferrite. The temperature dependence of the formation and development of nano-size oxide particles and δ-ferrite using mechanically alloyed 9Cr-ODS raw powder were investigated applying X-ray Diffraction and Small Angle X-ray Scattering measurement at SPring-8 and by Electron Probe Micro Analysis. In situ heating measurement techniques with XRD and SAXS enabled real-time observation of phase transformations and allowed correlation between formation of nano-size oxide particle and δ-ferrite.

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

    EPA Pesticide Factsheets

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

  18. Hot Deformation of AA6082 Containing Fine Intermetallic Particles

    NASA Astrophysics Data System (ADS)

    Poletti, Cecilia; Wójcik, Tomasz; Sommitsch, Christof

    2013-03-01

    Hot deformation of AA6082 aluminum alloy was studied by compression tests carried out between 573 K and 823 K (300 °C and 550 °C) under a wide range of strain rates. Light optical and scanning electron microscopy were used to study the as-received microstructure, which consisted of elongated, partially recrystallized grains containing fine Mg2Si and AlFeMnSi particles. The hot-deformed material showed the effects of dynamic recovery, i.e., small low angle grain boundary formation and dislocation pinning by fine particles. The flow data were used to calculate the constitutive equations, obtaining high values of n exponent. This behavior was attributed to the interaction of particles with dislocations during hot deformation. Threshold stresses were introduced to adjust the constitutive equation to a n exponent value of 5 at high stresses and a value of 3 in the low stresses range, which was related to dislocations' climbing and sliding and thus to dynamic recovery. The threshold values were related to the detachment stresses in close connection with the precipitation state which was a function of the deformation temperature.

  19. A novel low-temperature preparation of Ni-Zn ferrite and the properties of the ultrafine particles formed

    NASA Astrophysics Data System (ADS)

    Chen, C. J.; Bridger, K.; Winzer, S. R.; PaiVerneker, V.

    1988-04-01

    Ultrafine particles of nickel-zinc ferrite have been formed from solutions of metal nitrates by coprecipitation with hydrazine, followed by aging at 90 °C. The crystallites either aggregate into much larger clusters or form single particles, depending upon the preparation conditions, and vary in size from 30 to ≊300 Å. Saturation magnetizations (Ms) of the ferrites varied from 40 to 65 emu/g and the coercivities from 1 to ≊100 Oe. Increasing hydrazine concentrations tended to produce particles with lower Ms. However, for hydrazine/metal ratios below unity, decreasing the hydrazine concentration dramatically lowered the Ms value. Particles formed without hydrazine (e.g., by aging hydroxides precipitated with potassium hydroxide) did not appear to be magnetic. Variations of the magnetic properties and lattice parameters as a function of preparation conditions will be discussed.

  20. Preparation of nanocrystalline NiZnCu ferrite particles by sol-gel method and their magnetic properties

    NASA Astrophysics Data System (ADS)

    Yan, Shifeng; Geng, Jianxin; Yin, Li; Zhou, Enle

    2004-06-01

    Polyvinyl alcohol (PVA) was first used as chelating agent and metal nitrates as precursor of ferrite in the fabrication of nanocrystalline Ni 0.65Zn 0.35Cu 0.1Fe 1.9O 4 particles by the sol-gel method. The thermal decomposition process of dried gel was studied by thermogravimetry (TG), differential thermal analysis (DTA) and infrared spectra (IR). The structural and magnetic properties of resultant particles were investigated by X-ray diffraction (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. The dependence of the decomposition of dried gel, the formation of spinel structured NiZnCu ferrite, the sizes of annealed particles, the saturation magnetization and coercivity of annealed particles on annealing temperature is presented.

  1. Polyfunctional bioceramics modified by M-type hexagonal ferrite particles for medical applications

    NASA Astrophysics Data System (ADS)

    Tkachenko, M. V.; Ol'Khovik, L. P.; Kamzin, A. S.

    2011-06-01

    Magnetic bioceramics based on Ca5(PO4)3OH hydroxyapatite and M-type hexagonal ferrite (HF) microcrystals has been synthesized and characterized. The material consists of a biocompatible apatite matrix containing dispersed M-type HF particles. The latter component makes the magnetic characteristics of synthesized ceramics significantly higher as compared to those of iron-oxide-modified bioglass ceramics currently used in medicine. These properties increase the efficiency and prospects of using the new bioceramics in medicine, in particular, for the hyperthermal treatment of malignant tumors. Thus, a new class of materials is created, which combine the necessary biocompatibility and biological activity of Ca5(PO4)3OH hydroxyapatite and high magnetic characteristics of M-type HF microcrystals.

  2. Process for making ultra-fine ceramic particles

    DOEpatents

    Stangle, Gregory C.; Venkatachari, Koththavasal R.; Ostrander, Steven P.; Schulze, Walter A.

    1995-01-01

    A process for producing ultra-fine ceramic particles in which droplets are formed from a ceramic precursor mixture containing a metal cation, a nitrogen-containing fuel, a solvent, and an anion capable of participating in an anionic oxidation-reduction reaction with the nitrogen containing fuel. The nitrogen-containing fuel contains at least three nitrogen atoms, at least one oxygen atom, and at least one carbon atom. The ceramic precursor mixture is dried to remove at least 85 weight percent of the solvent, and the dried mixture is then ignited to form a combusted powder.

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

    PubMed

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

    2014-12-15

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

  4. 77 FR 65346 - Determination of Attainment for the Sacramento Nonattainment Area for the 2006 Fine Particle...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... Particle Standard; California; Determination Regarding Applicability of Clean Air Act Requirements AGENCY... Sacramento nonattainment area in California has attained the 2006 24-hour fine particle (PM 2.5 ) National... for the 2006 24-hour NAAQS for fine particles (generally referring to particles less than or equal to...

  5. 78 FR 887 - Determination of Attainment for the Nogales Nonattainment Area for the 2006 Fine Particle...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-07

    ... Particle Standard; Arizona; Determination Regarding Applicability of Clean Air Act Requirements AGENCY... the Nogales nonattainment area in Arizona has attained the 2006 24-hour fine particle (PM 2.5... fine particles (generally referring to particles less than or equal to 2.5 micrometers in diameter, PM...

  6. Study of fine and ultrafine particles for coal cleaning

    SciTech Connect

    Birlingmair, D.; Buttermore, W.; Chmielewski, T.; Pollard, J.

    1990-04-01

    During the second quarter of work on this new project, critical review of the literature continued. Several new references related to gravity separation were identified and evaluated. A synopsis was assembled to summarize techniques developed by various researchers for the float/sink separation of ultrafine coal. In the reviewed literature, it was commonly concluded that substantial improvements in washability results for ultrafine coals can be obtained only through the application of dynamic (centrifugal) procedures, and through the use of dispersing aids such as ultrasound and surfactants. These results suggest the presence of physicochemical phenomena, typical of colloidal systems. In theoretical studies this quarter, the effects of Brownian motion on fine particle sedimentation have been identified and theoretically quantitated. The interaction between Brownian and gravitational forces was calculated, and a model was prepared to permit estimation of critical particle size in float/sink separations. In laboratory studies this quarter, aliquots of Upper Freeport coal were prepared and subjected to laboratory float/sink separations to investigate the relative effectiveness of static and centrifugal techniques for fine and ultrafine coal. This series will verify results of earlier work and provide a basis for comparing the effects which may result from further modifications to the separation techniques resulting from insights gained in the basic phenomena governing float/sink processes. 15 refs., 6 figs., 1 tab.

  7. The mortality impacts of fine particles in France.

    PubMed

    Pascal, Mathilde; de Crouy Chanel, Perrine; Wagner, Vérène; Corso, Magali; Tillier, Claude; Bentayeb, Malek; Blanchard, Myriam; Cochet, Amandine; Pascal, Laurence; Host, Sabine; Goria, Sarah; Le Tertre, Alain; Chatignoux, Edouard; Ung, Aymeric; Beaudeau, Pascal; Medina, Sylvia

    2016-11-15

    Worldwide, air pollution has become a main environmental cause of premature mortality. This burden is largely due to fine particles. Recent cohort studies have confirmed the health risks associated with chronic exposure to PM2.5 for European and French populations. We assessed the mortality impact of PM2.5 in continental France using these new results. Based on a meta-analysis of French and European cohorts, we computed a shrunken estimate of PM2.5-mortality relationship for the French population (RR 1.15 [1.05:1.25] for a 10μg/m(3) increase in PM2.5). This RR was applied to PM2.5 annual concentrations estimated at a fine spatial scale, using a classical health impacts assessment method. The health benefits associated with alternative scenarios of improving air quality were computed for 36,219 French municipalities for 2007-2008. 9% of the total mortality in continental France is attributable to anthropogenic PM2.5. This represents >48,000 deaths per year, and 950,000years of life lost per year, more than half occurring in urban areas larger than 100,000 inhabitants. If none of the municipalities exceeded the World Health Organization guideline value for PM2.5 (10μg/m(3)), the total mortality could be decreased by 3%, corresponding to 400,000years of life saved per year. Results were consistent with previous estimates of the long-term mortality impacts of fine particles in France. These findings show that further actions to improve air quality in France would substantially improve health. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Effect of particle size on structural, magnetic and dielectric properties of manganese substituted nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, E. Ranjith; Kamzin, Aleksandr S.; Prakash, T.

    2015-03-01

    Mn substituted NiFe2O4 ferrite nanoparticles (Mn-NiFe2O4) were synthesized by the auto-combustion method. Their actions were carried out at different fuel ratios (50%, 75% and 100%). The nanoparticles have been investigated by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The average crystallite size of the synthesized and annealed samples was between 25 and 75 nm, which were found to be dependent on both fuel ratio and annealing temperatures. However, lattice parameters, interplanar spacing and grain size were controlled by varying the fuel ratio. Magnetic characterizations of the nanoparticles were carried out using a vibrating sample magnetometer at room temperature. The saturation magnetization was computed and found to lie between 6 emu/g and 57 emu/g depending on the particle size of the studied sample. The coercivity was found to exhibit non-monotonic behavior with the particle size. Such behavior can be accounted for by the combination between surface anisotropy and thermal energies. The value of dielectric constant and dielectric loss was found to exhibit almost linear dependence on the particle size.

  9. Treatment and recovery of larger particles of fine oxidized coal

    SciTech Connect

    Finch, R.E.

    1980-09-16

    This invention relates to a method and treating agent for increasing the yield of larger particles of fine oxidized coal where the particle size is 28 X 100 mesh and preferably 28 X 70 mesh and where said coal particles are concentrated by froth flotation. The method consists of utilizing as a promoter an alkali metal or ammonium polyacrylate. A preferred promoter is about 0.05-1.5 lbs of sodium polyacrylate latex per ton of dry coal (0.017-0.5 lb of dry sodium polyacrylate per ton of dry coal), having an average molecular weight of about 100,000, to 1, 000,000 and more, with a preferred range of 1,000,000 or more. This preferred promoter or frothing aid for oxidized coal is a water-in-oil latex of sodium polyacrylate used with a water-inoil emulsifier and preferably used with an alcohol-type frother. The latex may be utilized neat and self inverts with the assistance of an oil-in-water surfactant and the water in the system upon application to form an oil-in-water emulsion, or it may be used as a two part system with an activator (Aqueous) to promote inversion. Additionally, the latex emulsion recovers larger particles in the size 100 mesh and greater and preferably in the range 28 X 70 mesh.

  10. Fine and ultrafine particle emissions from microwave popcorn.

    PubMed

    Zhang, Q; Avalos, J; Zhu, Y

    2014-04-01

    This study characterized fine (PM2.5 ) and ultrafine particle (UFP, diameter < 100 nm) emissions from microwave popcorn and analyzed influential factors. Each pre-packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3 min. The number concentration and size distribution of UFPs and PM2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil-lined original package or a brown paper bag. UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil-lined original package with a brown paper bag significantly reduced the peak concentration by 24-87% for total particle number and 36-70% for PM2.5 . A positive relationship was observed between both UFP number and PM2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9 × 10(10) to 8.0 × 10(10) No./min for total particle number and from 134 to 249 μg/min for PM2.5 .

  11. SOURCE STRENGTHS OF ULTRAFINE AND FINE PARTICLES DUE TO COOKING WITH A GAS STOVE

    EPA Science Inventory

    Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes, including ultrafine particles, produced during cooking. In this study, semicontinuous instruments with fine size discriminating ability were us...

  12. SOURCE STRENGTHS OF ULTRAFINE AND FINE PARTICLES DUE TO COOKING WITH A GAS STOVE

    EPA Science Inventory

    Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes, including ultrafine particles, produced during cooking. In this study, semicontinuous instruments with fine size discriminating ability were us...

  13. Control Experiment of Positively Charged Fine Particles at the Atmospheric Pressure

    SciTech Connect

    Yokota, Toshiaki; Ando, Ayumi; Sato, Noriyoshi

    2005-10-31

    It is already reported that the negatively charged fine particle flow was controlled by application of external electric field. The control of positively charged fine particles was examined in this experiment.The fine particles are able to take charges in the air under the atmospheric pressure by irradiation of UV light. The control of the positively charged fine particles has been attempted by the external electric field applied the negative potential. The fine particles for experiments are volcanic ashes, nylon 16, glass, and ice. Experiment was performed in the T-shaped glass chamber under the atmospheric pressure. The halogen lamp (500 W) was used to exit the electrons from particles by photo-emission. The ring and disk electrodes to control the positively charged particles were set at the bottom of chamber. The parallel electrodes were set at the middle of chamber and horizontal static electric fields (E = 0 {approx} 210 V/cm) were created in order to estimate the charge of fine particles. The charges of particle were estimated by the deflection of particle trajectory in the static electric fields and particle velocity. The estimated charges were 104e {approx} 5x106e and 103e {approx} 105e for volcanic ashes and nylon 16, respectively. When positively charged particles were introduced into collecting electrodes, the fine particles are collected in the electrodes. The result of control of positively charged fine particles is shown in this conference.

  14. Combustion Synthesis and Properties of Fine Particle Spinel Manganites

    NASA Astrophysics Data System (ADS)

    Dhas, N. Arul; Patil, K. C.

    1993-02-01

    Fine particle spinel manganites have been prepared by thermal decomposition of the precursors N2H5M1/3Mn2/3(N2H3COO)3 · H2O (M = Co and Ni) and M1/3 Mn2/3(N2H3COO)2 · 2H2O (M = Mg and Zn), as well as by the combustion of redox mixtures containing M(II) nitrate (M = Mg, Co, Ni, Cu, and Zn), Mn(II) nitrate, and maleic hydrazide (MH) in the required molar ratio. Both the precursor and redox mixtures undergo self-propagating, gas-producing, exothermic reactions once ignited at 250-375°C to yield corresponding manganites in less than 5 min. Formation of single phase products was confirmed by X-ray powder diffraction patterns. The manganites are of submicrometer size and have surface area in the range 20-76 m2/g.

  15. Emissions of fine particle fluoride from biomass burning.

    PubMed

    Jayarathne, Thilina; Stockwell, Chelsea E; Yokelson, Robert J; Nakao, Shunsuke; Stone, Elizabeth A

    2014-11-04

    The burning of biomasses releases fluorine to the atmosphere, representing a major and previously uncharacterized flux of this atmospheric pollutant. Emissions of fine particle (PM2.5) water-soluble fluoride (F-) from biomass burning were evaluated during the fourth Fire Laboratory at Missoula Experiment (FLAME-IV) using scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) and ion chromatography with conductivity detection. F- was detected in 100% of the PM2.5 emissions from conifers (n=11), 94% of emissions from agricultural residues (n=16), and 36% of the grasses and other perennial plants (n=14). When F- was quantified, it accounted for an average (±standard error) of 0.13±0.02% of PM2.5. F- was not detected in remaining samples (n=15) collected from peat burning, shredded tire combustion, and cook-stove emissions. Emission factors (EF) of F- emitted per kilogram of biomass burned correlated with emissions of PM2.5 and combustion efficiency, and also varied with the type of biomass burned and the geographic location where it was harvested. Based on recent evaluations of global biomass burning, we estimate that biomass burning releases 76 Gg F- yr(-1) to the atmosphere, with upper and lower bounds of 40-150 Gg F- yr(-1). The estimated F- flux from biomass burning is comparable to total fluorine emissions from coal combustion plus other anthropogenic sources. These data demonstrate that biomass burning represents a major source of fluorine to the atmosphere in the form of fine particles, which have potential to undergo long-range transport.

  16. Effect of particle size, fraction and carbide banding on deformation and damage behavior of ferrite-cementite steel under tensile/shear loads

    NASA Astrophysics Data System (ADS)

    Zhuang, Xincun; Ma, Siming; Zhao, Zhen

    2017-01-01

    Deformation and damage behavior of ferrite-cementite steel was investigated using microstructure-based representative volume element (RVE) methodology. A series of automatically generated 2D RVEs with ferrite matrix and globular cementite particles were generated as representative of various microstructures. The geometrically necessary dislocation (GND) accumulation at the ferrite-cementite interphase was also studied by introducing an intermediate layer around the cementite particles. Damage mechanisms such as ductile fracture in ferrite matrix, brittle fracture in cementite, and decohesion at ferrite-cementite interphase were considered to study the fracture modes. The relationships between interface strength and particle size were estimated according to the modified Argon criterion and showed satisfactory agreement with related works. The influences of microstructural features, such as particle size, particle fraction and carbide banding, on deformation and damage evolution were investigated under tensile and shear loads. Simulation results indicated that small particle size and particle fraction could postpone the initial decohesion under both tensile and shear loads, while carbide banding can lead to early fracture due to local stress concentration, which has potential to cause the loss of ductility and premature failure. These adverse effects become more severe when more cementite particles remain in the band or the gather density of the cementite particles in the band becomes higher.

  17. Sources of fine particle composition in New York city

    NASA Astrophysics Data System (ADS)

    Li, Zheng; Hopke, Philip K.; Husain, Liaquat; Qureshi, Sumizah; Dutkiewicz, Vincent A.; Schwab, James J.; Drewnick, Frank; Demerjian, Kenneth L.

    Fine particle composition data from samples collected at Queens College during July 2001 were studied using positive matrix factorization (PMF). The sampling systems are an integrated filter sampler with a 6-h sampling time interval, an aerosol mass spectrometer (AMS) with a 10-min sampling time interval and a particle-into-liquid sampler with ion chromatography (PILS-IC) with 15-min sampling time interval. The data from the AMS and the PILS-IC were aggregated to 6-h average values for the PMF calculation. Sulfate, ammonium, and nitrate data were compared among the different instruments. The PMF method uses the estimated errors in the data to provide optimal point-by-point weighting and permits efficient treatment of missing and below detection limit values. Six source categories were resolved from the data. They are: secondary sulfate with high concentration SO 42-; secondary nitrate with the presence of high concentration NO 3-; motor vehicle emissions with high concentration of OC and Zn; road dust represented by Al, Ca, Fe, and K; sea salt with high concentration of Cl and Na; and oil combustion marked by the presence of Ni and V.

  18. Characteristics of the Electromagnetic Wave Absorbers of Composites Made of Ni-Zn Ferrite and Isolated SiO2 Particles

    NASA Astrophysics Data System (ADS)

    Kusunoki, Hiroki; Hiraki, Kiyohiro; Kondo, Takatoshi; Takada, Kazushi; Yoshikado, Shinzo

    It is found from simulation study that electromagnetic wave absorbers made of composites of Ni-Zn ferrite and SiO2 particles, which are mutually isolated each other in the continuous medium of Ni-Zn ferrite, show absorption in the frequency region both below and above 1GHz. The spray method is proposed to fabricate such composites in this study. The thin films of Ni-Zn ferrite can be coated on the surface of SiO2 particles by the spray thin film deposition method. It is confirmed by XRD and the electromagnetic characteristics measurement. The measured complex permeability approached to the calculated result using the isolation model of SiO2 particles in the Ni-Zn ferrite medium than using Lichtenecker’s logarithm mixed low.

  19. Characterization of the interactions within fine particle mixtures in highly concentrated suspensions for advanced particle processing.

    PubMed

    Otsuki, Akira; Bryant, Gary

    2015-12-01

    This paper aims to summarize recent investigations into the dispersion of fine particles, and the characterization of their interactions, in concentrated suspensions. This summary will provide a better understanding of the current status of this research, and will provide useful feedback for advanced particle processing. Such processes include the fabrication of functional nanostructures and the sustainable beneficiation of complex ores. For example, there has been increasing demand for complex ore utilization due to the noticeable decrease in the accessibility of high grade and easily extractable ores. In order to maintain the sustainable use of mineral resources, the effective beneficiation of complex ores is urgently required. It can be successfully achieved only with selective particle/mineral dispersion/liberation and the assistance of mineralogical and particle characterization.

  20. Magnetic heating by silica-coated Co-Zn ferrite particles

    NASA Astrophysics Data System (ADS)

    Veverka, M.; Závěta, K.; Kaman, O.; Veverka, P.; Knížek, K.; Pollert, E.; Burian, M.; Kašpar, P.

    2014-02-01

    This study is aimed at the preparation of silica-coated nanoparticles of cobalt-zinc ferrite and their heating properties with respect to potential application in magnetic fluid hyperthermia. The magnetic cores of Co0.4Zn0.6Fe2O4+γ possessing two different sizes were prepared by the coprecipitation method followed by annealing and mechanical treatment. The subsequent encapsulation of the samples by silica led to colloidally stable suspensions in water. The single phase character of the cores was confirmed by x-ray powder diffraction while detailed studies of the coated products by transmission electron microscopy and x-ray photoelectron spectroscopy showed that the silica shell had a thickness of at least 5 nm. The dc magnetic measurements were employed in order to determine the concentrations of magnetic particles in suspensions and to analyse the distribution of blocking temperatures. The heating efficiency of the nanoparticles was studied simultaneously by means of magnetic and calorimetric measurements in various ac fields. Specifically, the magnetic losses were calculated from the ac hysteresis loops while the heating effect of the nanoparticles was determined by measuring the time dependence of the temperature of their suspensions. The evaluation of the heating power from the latter experiments was supplemented by deriving the corrections for non-adiabatic properties of the calorimeter. More accurate results enabled detailed analysis and comparison with data published for other heating agents.

  1. Residential infiltration of fine and ultrafine particles in Edmonton

    NASA Astrophysics Data System (ADS)

    Kearney, Jill; Wallace, Lance; MacNeill, Morgan; Héroux, Marie-Eve; Kindzierski, Warren; Wheeler, Amanda

    2014-09-01

    Airborne indoor particles arise from both indoor sources and ambient particles that have infiltrated indoors. The intra-urban variability of infiltration factors (Finf) is a source of measurement error in epidemiological studies estimating exposure from a central site measurement, hence information on the within and between-home variability of Finf is useful to better characterize ambient PM exposure. The objective of this paper was to estimate magnitudes and predictors of daily residential infiltration factors (Finf) and ambient/non-ambient components of indoor ultrafine particle (UFP) and fine particle (FP) concentrations. FPs and UFPs were measured continuously for 7 consecutive days in 74 Edmonton homes in winter and summer 2010 (50 homes in each season). Simultaneous measurements of outdoor (near-home) FP and ambient (at a central site) UFP concentrations were also measured. Daily infiltration factors were estimated for each home; considerable variability was seen within and between homes. For FPs, seasonal-averaged Finf (the average of the 7 daily Finf estimates) ranged from 0.10 to 0.92 in winter (median = 0.30, n = 49) and 0.31 to 0.99 in summer (median = 0.68, n = 48). For UFPs, the seasonal-averaged Finf ranged from 0.08 to 0.47 across homes in winter (median = 0.21, n = 33 houses) and from 0.16 to 0.94 in summer (median = 0.57, n = 48). The higher median Finf in summer was attributed to a high frequency of open windows. Daily infiltration factors were also estimated based on the indoor/outdoor PM1 sulfur ratio. These estimates were poorly correlated with DustTrak-based FP infiltration factor estimates; the difference may be due to losses of volatile components on the PM1 filter samples. Generalized linear mixed models were used to identify variables significantly associated with Finf and the non-ambient component of indoor FP and UFP concentrations. Wind speed was consistently associated with Finf across all seasons for both FPs and UFPs. The use of an

  2. Magnetization of nano-fine particles of Pd/Ni alloys

    NASA Astrophysics Data System (ADS)

    Nunomura, N.; Teranishi, T.; Miyake, M.; Oki, A.; Yamada, S.; Toshima, N.; Hori, H.

    1998-01-01

    In order to investigate the giant magnetic moment problem in nano-fine Pd alloys particles, enough amount of Pd/Ni fine particles with quite narrow diameter distribution have been prepared by chemical method. The magnetization of Pd/Ni alloy ultrafine particles has been systematically investigated by using a SQUID magnetometer. The magnetization remarkably increases above the concentration of 8% of Ni. This result indicates the giant moment in the ultrafine Pd/Ni alloy particles.

  3. Fine particle concentrations in buses and taxis in Florence, Italy

    NASA Astrophysics Data System (ADS)

    Fondelli, M. Cristina; Chellini, Elisabetta; Yli-Tuomi, Tarja; Cenni, Isabella; Gasparrini, Antonio; Nava, Silvia; Garcia-Orellana, Isabel; Lupi, Andrea; Grechi, Daniele; Mallone, Sandra; Jantunen, Matti

    On October 2004, a sampling survey was carried out in Florence to estimate urban fine particle exposure concentrations inside commuting vehicles during workdays characterized by heavy traffic. Portable samplers were positioned inside four regularly scheduled diesel-powered buses and four taxis during eight weekdays. Each sampler consisted of a 2.5 μm size pre-separator cyclone, a direct-reading data logging photometer (pDR-1200), and a 4 L min -1 filter sampler for the determination of PM 2.5 mass concentration. Based on reflectance analysis measurements, a PM 2.5 Black Smoke Index was determined for each filter, and the elemental composition of the PM 2.5 was analyzed by Particle Induced X-ray Emission (PIXE). PM 2.5 mass concentrations inside the vehicles correlated well with the urban ambient air PM 2.5 concentrations measured at the fixed-site monitoring stations. The PM 2.5 excess above the urban ambient level was on average 32 μg m -3 (range: 22-52 μg m -3) and 20 μg m -3 (range: 11-29 μg m -3) in buses and taxis, respectively. The PM 2.5-bound sulfur concentration was also higher in the buses than in the taxis. Based on daily Time-Microenvironment-Activity-Diary (TMAD) data, the Florentines spend on average 9.7% of their day in traffic, and the corresponding average exposure is approximately 12% of their daily PM 2.5 personal exposure. The obtained data could be used to plan interventions to minimize the PM 2.5 citizen exposures in commuting.

  4. Loss of Fine Particle Ammonium from Denuded Nylon Filters

    SciTech Connect

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

    2006-08-01

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH4NO3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, Illinois (February 2003), San Gorgonio, California (April 2003 and July 2004), Grand Canyon National Park, Arizona (May, 2003), Brigantine, New Jersey (November 2003), and Great Smoky Mountains National Park (NP), Tennessee (July–August 2004). Samples were collected over 24-hr periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, Illinois to 28% in San Gorgonio, California in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(--III) (particulate NH4+ plus gaseous NH3) present as gaseous NH3. The amount of ammonium lost at most sites could be explained by the amount of NH4NO3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH4NO3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  5. Loss of fine particle ammonium from denuded nylon filters

    NASA Astrophysics Data System (ADS)

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William; Collett, Jeffrey L.

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH 4NO 3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, IL (February 2003), San Gorgonio, CA (April 2003 and July 2004), Grand Canyon NP, AZ (May, 2003), Brigantine, NJ (November 2003), and Great Smoky Mountains National Park (NP), TN (July-August 2004). Samples were collected over 24 h periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, IL to 28% in San Gorgonio, CA in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(-III) (particulate NH 4++gaseous NH 3) present as gaseous NH 3. The amount of ammonium lost at most sites could be explained by the amount of NH 4NO 3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH 4NO 3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  6. The temperature dependence of magnetic properties of Zn-Ti substituted Ba-ferrite particles for magnetic recording

    NASA Astrophysics Data System (ADS)

    Wei, Fulin; Lu, Mai; Yang, Zheng

    1999-01-01

    It was shown that the morphological and magnetic properties of Zn-Ti doped Ba-ferrite particles are suitable for magnetic recording. In order to clarify the temperature dependence of the magnetic properties of these particles, BaFe 10.8-2 xZn xTi xO 19 particles with the nominal composition x=0.0-0.50 were prepared by synthesis from salt melts. The saturation magnetization Ms, magnetic anisotropy field HA and magnetocrystalline anisotropy constant K1 of the above-mentioned particle assemblies were estimated by using the law of approach to saturation of polycrystalline ferrite, and the Curie temperature Tc was determined by the thermodynamic relation. With an increasing x, the Tc decreased, while the lattice parameters a, c and M s have an unnoticeable maximum at x=0.20. The Hc( T) curves of samples with different x show that all particles have positive temperature coefficient in the vicinity of room temperature, which decreases with increasing x. The Ms( T), H A(T) and K 1(T) were determined and discussed.

  7. 40 CFR 52.247 - Control Strategy and regulations: Fine Particle Matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.247 Section 52.247 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Strategy and regulations: Fine Particle Matter. (a) Determination of Attainment: Effective February 8, 2013...

  8. 40 CFR 52.247 - Control Strategy and regulations: Fine Particle Matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.247 Section 52.247 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Strategy and regulations: Fine Particle Matter. (a) Determination of Attainment: Effective February 8, 2013...

  9. A Study on Hydrodynamic Behavior of Fine Sediment in Retention Structure Using Particle Image Velocimetry.

    PubMed

    MoayeriKashani, Masoumeh; Hin, Lai Sai; Ibrahim, Shaliza; Sulaiman, Nik Meriam Nik

    2016-12-01

      Detention ponds are one type of stormwater best management practices (BMPs) that can be used for the quantity control of stormwater. The pond works by reducing peak discharge downstream through temporary storage and gradual release. In this paper, a new experimental procedure using particle image velocimetry (PIV) is introduced for a two-dimensional study of the hydrodynamic behavior of fine particles in a specially designed sediment basin. The hydrodynamic behavior of fine particles under different hydraulics parameters was achieved by shifting outlet placement, using different particle-size diameters, varying the distance of the inlet from the water surface, and varying the flow rate. The same inlet and outlet level reduced fine-particle dispersion and a lower flow rate assisted with controlling high siltation. Furthermore, smaller spherical particles had more influence on fine particle suspension. Therefore, controlling the hydraulic parameters can decrease the siltation problem level.

  10. High-temperature in-situ TEM straining of the interaction with dislocations and particles for Cu-added ferritic stainless steel.

    PubMed

    Kobayashi, Shuhei; Kaneko, Kenji; Yamada, Kazuhiro; Kikuchi, Masao; Kanno, Norihiro; Hamada, Junichi

    2014-11-01

    IntroductionCu is always present in the matrix when ferritic steels were prepared from ferrous scrap. When the ferritic steels are aged thermally, Cu precipitates start appear and disperse finely and homogeneously [1], which may make the steels strengthened by precipitation hardening. In this study, the interaction between Cu precipitates and dislocations was exmined via high-temperature in-situ TEM straining. ExperimentalCu-added ferritic stainless steel (Fe-18.4%Cr-1.5%Cu) was used in the present study. Specimen was aged at1073 K for 360 ks. Samples for TEM observation were prepared by focused ion beam (FIB; Quanta 3D 200i) method. Microstructure of specimen was analyzed by JEM-3200FSK and high-temperature in-situ TEM straining was conducted using JEM-1300NEF. Results and discussionInteraction between Cu precipitates and dislocation is seen from consecutive TEM images acquired by in-situ TEM straining at 1073 K, as shown in Fig.1. The size of Cu precipitates was about 70 nm and several dislocations were present within the field of view. In particular, progressing dislocations contacted with the Cu precipitate at right angle, as indicated by arrows in Fig.1 (b) to (d). This result implies that there is an attractive interaction between dislocations and the Cu precipitate. This is attributed to the fact that Stress field of dislocations was easily relaxed in interface between the Cu precipitate and matrix because of lattice and interface diffusion as well as slip in the interface [2,3]. Furthermore, dislocations pass through the particle after contacting it, so that the interaction with dislocations and particles should be explained by Srolovitz mechanism [4].jmicro;63/suppl_1/i28/DFU083F1F1DFU083F1Fig. 1.TEM images foucused on interaction with dislocations and partticles. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Sources of fine particle composition in the northeastern US

    NASA Astrophysics Data System (ADS)

    Song, Xin-Hua; Polissar, Alexandr V.; Hopke, Philip K.

    Fine particle composition data obtained at three sampling sites in the northeastern US were studied using a relatively new type of factor analysis, positive matrix factorization (PMF). The three sites are Washington, DC, Brigantine, NJ and Underhill, VT. The PMF method uses the estimates of the error in the data to provide optimal point-by-point weighting and permits efficient treatment of missing and below detection limit values. It also imposes the non-negativity constraint on the factors. Eight, nine and 11 sources were resolved from the Washington, Brigantine and Underhill data, respectively. The factors were normalized by using aerosol fine mass concentration data through multiple linear regression so that the quantitative source contributions for each resolved factor were obtained. Among the sources resolved at the three sites, six are common. These six sources exhibit not only similar chemical compositions, but also similar seasonal variations at all three sites. They are secondary sulfate with a high concentration of S and strong seasonal variation trend peaking in summer time; coal combustion with the presence of S and Se and its seasonal variation peaking in winter time; oil combustion characterized by Ni and V; soil represented by Al, Ca, Fe, K, Si and Ti; incinerator with the presence of Pb and Zn; sea salt with the high concentrations of Na and S. Among the other sources, nitrate (dominated by NO 3-) and motor vehicle (with high concentrations of organic carbon (OC) and elemental carbon (EC), and with the presence of some soil dust components) were obtained for the Washington data, while the three additional sources for the Brigantine data were nitrate, motor vehicle and wood smoke (OC, EC, K). At the Underhill site, five other sources were resolved. They are wood smoke, Canadian Mn, Canadian Cu smelter, Canadian Ni smelter, and another salt source with high concentrations of Cl and Na. A nitrate source similar to that found at the other sites could

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

    NASA Astrophysics Data System (ADS)

    Park, Jungsu; Hunt, James R.

    2017-09-01

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

  13. Indoor concentrations of fine particles and particle-bound PAHs in Gothenburg, Sweden

    NASA Astrophysics Data System (ADS)

    Johannesson, S.; Bergemalm-Rynell, K.; Strandberg, B.; Sällsten, G.

    2009-02-01

    Fine particles are formed in a variety of processes, both natural and anthropogenic. Epidemiological studies have shown an association between exposure to particulate matter and adverse health effects. Airborne particles contain a variety of compounds, including polycyclic aromatic hydrocarbons (PAHs), and several of the PAHs are known or suspected carcinogens. In this study, stationary measurements of PM2.5 were performed in the residences of 20 study participants along with simultaneous monitoring at an urban background site. The collected particle mass was then analyzed for its content of some particle-bound PAHs using GC-MS. The median level of PM2.5 indoors was 7.3 μg/m3 and in urban background 5.3 μg/m3. For benzo(a)pyrene (B(a)P) the corresponding results were 10 pg/m3 and 35 pg/m3, respectively. There were significant correlations between indoor and ambient levels for both PM2.5 (rs=0.58, p=0.02) and B(a)P (rs=0.67, p=0.007). No significant correlation was, however, found between the concentration of PM2.5 and the associated levels of the investigated PAH compounds. This finding implies that exposure to B(a)P or other particle-bound PAH components needs to be separately assessed.

  14. NanoFerrite Particle Based Radioimmunonanoparticles: Binding affinity and in vivo pharmacokinetics

    PubMed Central

    Natarajan, A.; Gruettner, C.; Ivkov, R.; DeNardo, G. L.; Mirick, G.; Yuan, A.; Foreman, A.; DeNardo, S. J.

    2008-01-01

    Dextran and PEG coated iron oxide nanoparticles (NP), when suitably modified to enable conjugation with molecular targeting agents, provide opportunities to target cancer cells. Monoclonal Antibodies, scFv, and peptides conjugated to 20-nm NP have been reported to target cancer for imaging and alternating magnetic field (AMF) therapy. The physical characteristics of NP's can affect their in vivo performance. Surface morphology, surface charge density, and particle size are considered important factors that determine pharmacokinetics, toxicity, and biodistribution. New NanoFerrite (NF) particles having improved specific AMF absorption rates and diameters of 30 nm and 100 nm were studied to evaluate the variation in their in vitro and in vivo characteristics in comparison to the previously studied 20 nm Superparamagnetic Iron Oxide (SPIO) NP. SPIO NP 20-nm, NF NP 30- and 100-nm were conjugated to 111In-DOTA-ChL6, a radioimmunoconjugate. Radioimmunoconjugates were conjugated to NP's using 25μg of RIC/mg of NP by carbodiimide chemistry. The radioimmunonanoparticles (RINP) were purified characterized by PAGE, cellulose acetate electrophoresis (CAE), live cell binding assays, and pharmacokinetics in athymic mice bearing human breast cancer (HBT 3477) xenografts. RINP (2.2 mg) were injected iv and whole body, blood and tissue data were collected at 4, 24, and 48 hours. The preparations used for animal study were >90% monomeric by PAGE and CAE. The immunoreactivity of the RINP was 40−60% compared to 111In-ChL6. Specific activities of the doses were 20−25μCi/2.2 mg and 6−11μg of MAb/2.2 mg of NP. Mean tumor uptakes (% ID/g ± SD) of each SPIO 20nm, NF 30nm, and 100nm RINP at 48h were 9.00 ± 0.8 (20nm), 3.0 ± 0.3 (30nm), and 4.5 ± 0.8 (100nm) respectively; the ranges of tissue uptakes were liver (16−32 ± 1 − 8), kidney (7.0−15 ± 1) spleen (8−17 ± 3 − 8) lymph nodes 5 − 6 ± 1 −2) and lung (2.0− 4 ± 0.1 − 2). In conclusion, this study

  15. NanoFerrite particle based radioimmunonanoparticles: binding affinity and in vivo pharmacokinetics.

    PubMed

    Natarajan, A; Gruettner, C; Ivkov, R; DeNardo, G L; Mirick, G; Yuan, A; Foreman, A; DeNardo, S J

    2008-06-01

    Dextran and PEG-coated iron oxide nanoparticles (NP), when suitably modified to enable conjugation with molecular targeting agents, provide opportunities to target cancer cells. Monoclonal antibodies, scFv, and peptides conjugated to 20 nm NP have been reported to target cancer for imaging and alternating magnetic field (AMF) therapy. The physical characteristics of NPs can affect their in vivo performance. Surface morphology, surface charge density, and particle size are considered important factors that determine pharmacokinetics, toxicity, and biodistribution. New NanoFerrite (NF) particles having improved specific AMF absorption rates and diameters of 30 and 100 nm were studied to evaluate the variation in their in vitro and in vivo characteristics in comparison to the previously studied 20 nm superparamagnetic iron oxide (SPIO) NP. SPIO NP 20 nm and NF NP 30 and 100 nm were conjugated to (111)In-DOTA-ChL6, a radioimmunoconjugate. Radioimmunoconjugates were conjugated to NPs using 25 microg of RIC/mg of NP by carbodiimide chemistry. The radioimmunonanoparticles (RINP) were purified and characterized by PAGE, cellulose acetate electrophoresis (CAE), live cell binding assays, and pharmacokinetics in athymic mice bearing human breast cancer (HBT 3477) xenografts. RINP (2.2 mg) were injected iv and whole body; blood and tissue data were collected at 4, 24, and 48 h. The preparations used for animal study were >90% monomeric by PAGE and CAE. The immunoreactivity of the RINP was 40-60% compared to (111)In-ChL6. Specific activities of the doses were 20-25 microCi/2.2 mg and 6-11 microg of mAb/2.2 mg of NP. Mean tumor uptakes (% ID/g +/- SD) of each SPIO 20 nm, NF 30 nm, and 100 nm RINP at 48 h were 9.00 +/- 0.8 (20 nm), 3.0 +/- 0.3 (30 nm), and 4.5 +/- 0.8 (100 nm), respectively; the ranges of tissue uptakes were liver (16-32 +/- 1-8), kidney (7.0-15 +/- 1), spleen (8-17 +/- 3-8), lymph nodes 5-6 +/- 1-2), and lung (2.0-4 +/- 0.1-2). In conclusion, this study

  16. FTIR and structural properties of co-precipitated cobalt ferrite nano particles

    NASA Astrophysics Data System (ADS)

    Hutamaningtyas, E.; Utari; Suharyana; Wijayanta, A. T.; Purnama, B.

    2016-11-01

    The FTIR and structural properties in co-precipitated cobalt ferrite (CoFe2O4) nanoparticles are discussed in this paper. The synthesis was conducted at temperatures of 75°C and 95°C following post annealing at 1200°C for 5 hours. Other modification samples were synthesis at temperature of 95°C and then annealing at temperature of 1000°C and 1200°C for 5 hours. For both modification of synthesis and annealing temperature, FTIR result showed a metal oxide at a wave number of 590 cm-1 which indicated cobalt ferrite nanoparticles. The crystalline structure was confirmed using x-ray diffraction that the high purity of cobalt ferrite was realized. Calculation of the cation distribution by using comparison I220/I222 and I422/I222 show that the synthesis and annealing temperature succesfully modify cation occupy the site octahedral and tetrahedral.

  17. Nano to micro particle size distribution measurement in the fluid by interactive force apparatus for fine particle processing.

    PubMed

    Fujita, Toyohisa; Dodbiba, Gjergj; Okaya, Katsunori; Matsuo, Seiji; Wang, Li Pang; Onda, Kana; Otsuki, Akira

    2013-12-01

    The direct measurement of fine particles size distribution of dispersions or coagulations in liquid is important for water purification, fine particles separation for recycling and mineral processing, as well as the new material production. The nano to micro particle size is usually measured by light scattering method; however, it is difficult to measure at high concentration of suspension. Here, a novel dynamical method by using the interactive force measurement between particles in liquid under electric field is used for measuring distribution of fine particle. Three types of nano to submicron particles, that is well-dispersed nano particles, coagulated nano particles and settled submicron particles, have been measured by interactive force measurement method. The particle size distributions are compered with the size distributions of dried particles measured by TEM or SEM. The well-dispersed nano particle size distribution by interactive force measurement is influenced by the nano size surfactant micelles. The size distribution of coagulated nano particles in water is larger than the result by TEM. On the other hand, the submicron nickel particle size distribution is similar with the one analyzed by SEM.

  18. Characterization of individual fine and ultrafine particles with a real-time single particle mass spectrometer

    NASA Astrophysics Data System (ADS)

    Reinard, Melissa S.

    2008-10-01

    Designed to analyze aerosols in ambient settings, the Real-Time Single Particle Mass Spectrometer (RSMS) provides a highly time-resolved measurement of the physical and chemical properties of individual fine (<2.5 mum dia.) and ultrafine (<0.1 mum dia.) particles. Understanding aerosols within this size range is crucial as these particles greatly impact both human health and the environment. Data collected by RSMS can be used identify particle sources and atmospheric processes. RSMS was deployed to Wilmington, DE during 2005-2006 as part of E-DATAS (Enhanced Delaware Air Toxics Assessment Study), a collaboration with the Delaware Department of Natural Resources (DNREC), the Environmental Protection Agency (EPA) and Duke University. Mass spectra acquired by RSMS were compared to a Scanning Mobility Particle Sizer (SMPS) to give a quantitative estimate of the chemical composition of PM1.0 (particulate matter <1.0 mum dia.) impacting the city. A method to collect and analyze particles directly from emission stacks of industrial facilities was developed to help identify sources of PM. Single particle mass spectrometry, in general, has remained primarily a qualitative technique due to several instrumental limitations which affect the data. First, the shot-to-shot variation in the laser pulse caused inconsistencies between the mass spectra of particles with the same composition. To determine whether this variation was systematic or random, the covariance between ions was calculated for laboratory generated aerosols. Second, RSMS was found to be highly sensitive to specific chemical species such as ammonium nitrate and transition/alkali metals. When these compounds are present in a particle they dominate the mass spectra and dwarf other the signal from other components to the baseline. To explore this bias, data collected by RSMS in Wilmington, DE was compared to data also collected in Wilmington by the quantitative NanoAerosol Mass Spectrometer (NAMS). Finally, a light

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

    PubMed

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

    2017-03-01

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

  20. A comparison of four gravimetric fine particle sampling methods.

    PubMed

    Yanosky, J D; MacIntosh, D L

    2001-06-01

    A study was conducted to compare four gravimetric methods of measuring fine particle (PM2.5) concentrations in air: the BGI, Inc. PQ200 Federal Reference Method PM2.5 (FRM) sampler; the Harvard-Marple Impactor (HI); the BGI, Inc. GK2.05 KTL Respirable/Thoracic Cyclone (KTL); and the AirMetrics MiniVol (MiniVol). Pairs of FRM, HI, and KTL samplers and one MiniVol sampler were collocated and 24-hr integrated PM2.5 samples were collected on 21 days from January 6 through April 9, 2000. The mean and standard deviation of PM2.5 levels from the FRM samplers were 13.6 and 6.8 microg/m3, respectively. Significant systematic bias was found between mean concentrations from the FRM and the MiniVol (1.14 microg/m3, p = 0.0007), the HI and the MiniVol (0.85 microg/m3, p = 0.0048), and the KTL and the MiniVol (1.23 microg/m3, p = 0.0078) according to paired t test analyses. Linear regression on all pairwise combinations of the sampler types was used to evaluate measurements made by the samplers. None of the regression intercepts was significantly different from 0, and only two of the regression slopes were significantly different from 1, that for the FRM and the MiniVol [beta1 = 0.91, 95% CI (0.83-0.99)] and that for the KTL and the MiniVol [beta1 = 0.88, 95% CI (0.78-0.98)]. Regression R2 terms were 0.96 or greater between all pairs of samplers, and regression root mean square error terms (RMSE) were 1.65 microg/m3 or less. These results suggest that the MiniVol will underestimate measurements made by the FRM, the HI, and the KTL by an amount proportional to PM2.5 concentration. Nonetheless, these results indicate that all of the sampler types are comparable if approximately 10% variation on the mean levels and on individual measurement levels is considered acceptable and the actual concentration is within the range of this study (5-35 microg/m3).

  1. Fine particle retention within stream storage areas at baseflow and in response to a storm event

    NASA Astrophysics Data System (ADS)

    Drummond, Jen; Harvey, Jud; Larsen, Laurel; González-Pinzón, Ricardo; Packman, Aaron

    2016-04-01

    Fine particles (1-100 μm), including particulate organic carbon (POC) and fine sediment, influence stream ecological functioning because they have a high affinity to sorb nitrogen and phosphorus, which are limited nutrients in aquatic ecosystems. These particles immobilize within in-stream storage areas, especially hyporheic sediments and benthic biofilms. However, fine particles are also known to remobilize at all flow conditions. The combination of immobilization and remobilization events leads to downstream transport and transient retention, which fuels stream ecosystems. The main objective of this study was to quantify immobilization and remobilization rates of fine particles that influence biogeochemical cycling in sand-and-gravel bed streams. During our field injection experiment, a thunderstorm driven spate allowed us to observe fine particle dynamics during both baseflow and in response to increased flow in the fifth-order stream Difficult Run, Virginia, USA. Solute and fine particles were measured within stream surface waters and porewaters at four different in-stream locations and multiple depths. Modeling of in-stream breakthrough curves (leading edge and initial decline before the storm) with a stochastic mobile-immobile model show that fine particles were mainly transported with the solute, but with additional net deposition. Porewater samples showed that flow paths within the stream sediments are complex and heterogeneous, with varying travel times depending on the in-stream location (i.e. channel thalweg, pool or lateral cavity). Higher filtration coefficients of fine particles were observed within the channel thalweg compared to the pool, and the filtration coefficient increased with sediment depth. Furthermore, we observed the accumulation of immobilized fine particles within hyporheic sediment and benthic biofilms on cobbles during baseflow and retention was evident even after the spate. Approximately 64% of fine particles were retained during

  2. Advances in Dusty Plasmas 6.Dusty Plasmas and Carbon Fine Particles

    NASA Astrophysics Data System (ADS)

    Hayashi, Yasuaki

    Formation and growth process of carbon fine particles in plasmas attract interests of researchers in the field not only of basic science but also of applied science. Since carbon has many bonding states, materials containing carbon could be formed in a variety of structures. Mechanism of the formation of the interstellar dusts and fine particles produced experimentally on earth is not well understood. This paper reports our experimental results on the formation of carbon fine particles in various laboratory conditions. Our results may suggest a mechanism of the formation of the interstellar dusts.

  3. Structural, Optical and EXAFS Studies of Nickel Substituted Copper Ferrites Nano-Particle by Sol-Gel Auto Combustion Method

    NASA Astrophysics Data System (ADS)

    Mishra, Ashutosh; khan, Mehjabeen; Jarabana, Kanaka M.; Bisen, Supriya

    2016-10-01

    The Cu-Ni ferrites with general formula Cu1-xNixFe2O4 (where x=0.0, 0.1, 0.2, 0.3) were prepared by sol gel method. The Extended X-ray absorption fine structure (EXAFS), X- ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) measurements were carried out. EXAFS spectra have been recorded at the k edge of Iron using the dispersive EXAFS (DEXAFS) beam line at 2.5 GeV at Indus -2 synchrotron radiation source RRCAT, Indore, India. The EXAFS data have been analyzed using the computer software Athena. These have been used to determine the bond lengths in these ferrites with the help of three different methods, namely, Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The phase uncorrected bond lengths have also been obtained from Fourier transformation method and the results obtained have been compared with the results obtained from LSS method, which also gives phase uncorrected bond lengths. XRD shows the structure is the tetragonal, and FTIR was used to determine the nature of the vibrational modes present in the system.

  4. Characterization of fine particles from machining in automotive plants.

    PubMed

    Dasch, Jean; D'Arcy, James; Gundrum, Aaron; Sutherland, John; Johnson, John; Carlson, David

    2005-12-01

    Sampling of the full range of particle sizes was carried out on 16 processes in six different General Motors plants over a period of 2.5 years. This article deals with particle characterization from five of the processes that relate to machining, specifically, wet machining with water-based fluids from old and new technology processes, grinding with straight oils from old and new technology processes, and dry machining. The concentrations measured by different instruments were in reasonable agreement, although the light-scattering instrument generally produced higher values than filters. Of the processes studied, the old technology grinding using straight oils generated the highest particle concentrations. The new technology controls (enclosed, vented machines) were highly effective but more so for large particles than small particles. The particle size distribution was shifted to smaller particles with enclosed processes. Dry machining generated the largest particles of all processes studied.

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

    PubMed

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

    2007-05-01

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

  6. Effect of cobalt substitution on structural and magnetic properties and chromium adsorption of manganese ferrite nano particles

    NASA Astrophysics Data System (ADS)

    Ahalya, K.; Suriyanarayanan, N.; Ranjithkumar, V.

    2014-12-01

    Manganese ferrite (MnFe2O4) and cobalt doped manganese ferrite (Mn1-xCoxFe2O4) with x=0, 0.2, 0.4, 0.6, and 0.8 are synthesized at pH 11 and an annealing temperature of 900 °C, through co-precipitation technique. The particle sizes are found to be in the range of 30-35 nm. The varying dopant concentrations influence the crystalline edges, surface morphology and magnetic properties of the samples. Particle size initially increases for the incorporation of cobalt up to x=0.6 and then decreases. As cobalt concentration increases, the saturation magnetization increases up to x=0.6 and then decreases. Stretching and bending of bonds at tetrahedral and octahedral sites respectively are noticed and they shift towards the longer wavelengths. The samples are tested for their application as adsorbents of toxic heavy metal Cr(VI). The adsorption efficiency variations with dopant concentrations of samples, quantity of adsorbent and concentrations of chromium are studied.

  7. Relationships involving fine-particle mass, fine-particle sulfur, and ozone during episodic periods at sites in and around St. Louis, Missouri

    SciTech Connect

    Altshuller, A.P.

    1985-01-01

    A number of investigations have been published on relationships involving particulate sulfate over regions of North America. Elevated concentrations of sulfate and ozone have been identified as occurring during the same periods in the summer months of the year in the United States. Particle sulfur and particle mass measurements obtained from the regional monitoring stations (RAMS) in and around St. Louis, Missouri, during the Regional Air Pollution Study (RAPS) have been discussed previously. Ozone measurements made in the RAPS study have received separate consideration. The large extended series of concurrent measurements of fine-particle sulfur, fine-particle mass, and ozone at both urban and nonurban locations in the St. Louis area provides an opportunity to examine relationships among these species in detail. The emphasis here is on the patterns of concentration of these species particularly during periods of especially high concentrations, episodic periods.

  8. Fine Particle Emissions from Residual Fuel Oil Combustion: Characterization and Mechanisms of Formation

    DTIC Science & Technology

    2000-08-04

    NC, 1999. 3 . Bachmann, J. D ., Damberg, R. J., Caldwell, J. C., Ed- wards, C., and Koman, P. D ., Review of the National Ambient Air Quality Standards...residual fuel oil combustion to be suspect, as far as emission of toxic fine particles is concerned. Build- ing upon previous work examining the...control number. 1. REPORT DATE 04 AUG 2000 2. REPORT TYPE N/A 3 . DATES COVERED - 4. TITLE AND SUBTITLE Fine Particle Emissions from Residual

  9. FINE PARTICLE EXPOSURE IS ASSOCIATED WITH ALTERED VENTRICULAR REPOLARIZATION

    EPA Science Inventory

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

  10. FINE PARTICLE EXPOSURE IS ASSOCIATED WITH ALTERED VENTRICULAR REPOLARIZATION

    EPA Science Inventory

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  12. Asthma-Related Outcomes in Patients Initiating Extrafine Ciclesonide or Fine-Particle Inhaled Corticosteroids

    PubMed Central

    Postma, Dirkje S.; Dekhuijzen, Richard; van der Molen, Thys; Martin, Richard J.; van Aalderen, Wim; Roche, Nicolas; Guilbert, Theresa W.; Israel, Elliot; van Eickels, Daniela; Khalid, Javaria Mona; Herings, Ron M.C.; Overbeek, Jetty A.; Miglio, Cristiana; Thomas, Victoria; Hutton, Catherine; Hillyer, Elizabeth V.

    2017-01-01

    Purpose Extrafine-particle inhaled corticosteroids (ICS) have greater small airway deposition than standard fine-particle ICS. We sought to compare asthma-related outcomes after patients initiated extrafine-particle ciclesonide or fine-particle ICS (fluticasone propionate or non-extrafine beclomethasone). Methods This historical, matched cohort study included patients aged 12-60 years prescribed their first ICS as ciclesonide or fine-particle ICS. The 2 cohorts were matched 1:1 for key demographic and clinical characteristics over the baseline year. Co-primary endpoints were 1-year severe exacerbation rates, risk-domain asthma control, and overall asthma control; secondary endpoints included therapy change. Results Each cohort included 1,244 patients (median age 45 years; 65% women). Patients in the ciclesonide cohort were comparable to those in the fine-particle ICS cohort apart from higher baseline prevalence of hospitalization, gastroesophageal reflux disease, and rhinitis. Median (interquartile range) prescribed doses of ciclesonide and fine-particle ICS were 160 (160-160) µg/day and 500 (250-500) µg/day, respectively (P<0.001). During the outcome year, patients prescribed ciclesonide experienced lower severe exacerbation rates (adjusted rate ratio [95% CI], 0.69 [0.53-0.89]), and higher odds of risk-domain asthma control (adjusted odds ratio [95% CI], 1.62 [1.27-2.06]) and of overall asthma control (2.08 [1.68-2.57]) than those prescribed fine-particle ICS. The odds of therapy change were 0.70 (0.59-0.83) with ciclesonide. Conclusions In this matched cohort analysis, we observed that initiation of ICS with ciclesonide was associated with better 1-year asthma outcomes and fewer changes to therapy, despite data suggesting more difficult-to-control asthma. The median prescribed dose of ciclesonide was one-third that of fine-particle ICS. PMID:28102056

  13. Asthma-Related Outcomes in Patients Initiating Extrafine Ciclesonide or Fine-Particle Inhaled Corticosteroids.

    PubMed

    Postma, Dirkje S; Dekhuijzen, Richard; van der Molen, Thys; Martin, Richard J; van Aalderen, Wim; Roche, Nicolas; Guilbert, Theresa W; Israel, Elliot; van Eickels, Daniela; Khalid, Javaria Mona; Herings, Ron M C; Overbeek, Jetty A; Miglio, Cristiana; Thomas, Victoria; Hutton, Catherine; Hillyer, Elizabeth V; Price, David B

    2017-03-01

    Extrafine-particle inhaled corticosteroids (ICS) have greater small airway deposition than standard fine-particle ICS. We sought to compare asthma-related outcomes after patients initiated extrafine-particle ciclesonide or fine-particle ICS (fluticasone propionate or non-extrafine beclomethasone). This historical, matched cohort study included patients aged 12-60 years prescribed their first ICS as ciclesonide or fine-particle ICS. The 2 cohorts were matched 1:1 for key demographic and clinical characteristics over the baseline year. Co-primary endpoints were 1-year severe exacerbation rates, risk-domain asthma control, and overall asthma control; secondary endpoints included therapy change. Each cohort included 1,244 patients (median age 45 years; 65% women). Patients in the ciclesonide cohort were comparable to those in the fine-particle ICS cohort apart from higher baseline prevalence of hospitalization, gastroesophageal reflux disease, and rhinitis. Median (interquartile range) prescribed doses of ciclesonide and fine-particle ICS were 160 (160-160) μg/day and 500 (250-500) μg/day, respectively (P<0.001). During the outcome year, patients prescribed ciclesonide experienced lower severe exacerbation rates (adjusted rate ratio [95% CI], 0.69 [0.53-0.89]), and higher odds of risk-domain asthma control (adjusted odds ratio [95% CI], 1.62 [1.27-2.06]) and of overall asthma control (2.08 [1.68-2.57]) than those prescribed fine-particle ICS. The odds of therapy change were 0.70 (0.59-0.83) with ciclesonide. In this matched cohort analysis, we observed that initiation of ICS with ciclesonide was associated with better 1-year asthma outcomes and fewer changes to therapy, despite data suggesting more difficult-to-control asthma. The median prescribed dose of ciclesonide was one-third that of fine-particle ICS.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  15. Effect of antisite formation on magnetic properties of nickel zinc ferrite particles

    NASA Astrophysics Data System (ADS)

    Ghosh, B.; Sardar, M.; Banerjee, S.

    2013-11-01

    In this report, we have investigated the effect of antisite ordering on the magnetic behavior of NixZn1-xFe2O4 nanoparticles for x = 0, 0.25, 0.5, 0.75, and 1. Observed magnetization versus temperature data show systematic gradual changes from antiferromagnetic to ferrimagnetic phase with increasing amount of Ni concentration. Saturation magnetization of the parent Zn ferrite increases when substituted by Ni and then decreases for concentration greater than x = 0.5. Coercivity also shows a concentration dependence. Saturation magnetization has no dependence on cooling field at all concentrations. For x = 0.5 the system act as an extremely soft magnetic material with highest saturation magnetization and lowest coercivity. Site occupancy by cations plays an important role for local moment imbalance between different antiferromagnetic sublattices giving rise to ferrimagnetic interaction upon Ni substituted in Zn ferrite.

  16. Method of separating and de-watering fine particles

    DOEpatents

    Yoon, Roe-Hoan

    2016-12-13

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

  17. The influence of annealing in the ferrite-plus-austenite phase field on the stability of vanadium carbide precipitates

    NASA Technical Reports Server (NTRS)

    Locci, I. E.; Michal, G. M.

    1989-01-01

    The effect of rapid excursions into the ferrite-plus-austenite two-phase field on V4C3 precipitates formed by tempering in the ferrite phases was investigated. Heat treatments were first performed to produce a starting microstructure of fine vanadium carbide particles precipitated in a ferrite matrix, and the microstructure was then subjected to various short-time heat treatment cycles that transformed part of the matrix to austenite. TEM was used to determine the effects of the matrix change on the size, morphology, and distribution of the vanadium carbide particles.

  18. Pulmonary response to intratracheal instillation of ultrafine versus fine titanium dioxide: role of particle surface area.

    PubMed

    Sager, Tina M; Kommineni, C; Castranova, Vincent

    2008-12-01

    The production and use of nanoparticles is growing rapidly due to the unique physical and chemical properties associated with their nano size and large surface area. Since nanoparticles have unique physicochemical properties, their bioactivity upon exposure to workers or consumers is of interest. In this study, the issue of what dose metric (mass dose versus surface area dose) is appropriate for toxicological studies has been addressed. Rats were exposed by intratracheal instillation to various doses of ultrafine or fine TiO2. At 1, 7, or 42 days post-exposure, inflammatory and cytotoxic potential of each particle type was compared on both a mass dosage (mg/rat) as well as an equal surface area dosage (cm2 of particles per cm2 of alveolar epithelium) basis. The findings of the study show that on a mass basis the ultrafine particles caused significantly more inflammation and were significantly more cytotoxic than the fine sized particles. However, when doses were equalized based on surface area of particles delivered, the ultrafine particles were only slightly more inflammogenic and cytotoxic when compared to the fine sized particles. Lung burden data indicate that ultrafine TiO2 appears to migrate to the interstitium to a much greater extent than fine TiO2. This study suggests that surface area of particles may be a more appropriate dose metric for pulmonary toxicity studies than mass of particles.

  19. Comparison of sulfur measurements from a regional fine particle network with concurrent acid modes network results

    SciTech Connect

    Bennett, R.L.; Stockburger, L.; Barnes, H.M.

    1994-01-01

    The Fine Particle Network (FPN), a system of fine particle (less than 2.5 micrometers) samplers, was operated at 41 sites selected from the Enviromental Protection Agency Acid MODES program during the two year period in 1988-90. The 24-hour sample results included fine particle mass and the most predominant chemical element concentrations determined by wavelength dispersive x-ray fluorescence analysis. Statistical summaries of the fine mass and sulfur concentrations by site and season were prepared. The availability of simultaneous particulate sulfate measurements from independent collection and analytical procedures provided an opportunity to examine their agreement and provide a more reliable data base for evaluation of regional particulate models and estimation of contribution to urban aerosol concentration.

  20. Ultrasonic agitation-floating classification of nano-sized Ba-Mg ferrites particles formed by using self-propagating high temperature synthesis and fabrication of nickel-ferrites thin sheet by pulse-electroforming.

    PubMed

    Choi, Yong

    2013-01-01

    Nickel-nano-sized ferrites composites sheet for electromagnetic shielding was produced by pulse-electroforming in a modified nickel sulfamate solution. The ferrite particles were prepared by self-propagating high temperature synthesis (SHS) followed by mechanical milling, and classified with an ultrasonic agitation-floating unit to obtain about 100 nm in size. Average combustion temperature and combustion propagating rate during SHS reaction were 1190 K and 5.8 mm/sec at the oxygen pressure of 1.0 MPa, respectively. The nickel-ferrite composite sheet had preferred orientation which (100) pole clearly concentrated to normal direction, whereas, (110) and (111) poles tended to split to the longitudinal direction, respectively. Maximum magnetization, residual magnetization and coercive force of the nano-sized ferrites were 27.13 A x m2/kg, 6.4 A x m2/kg and 14.58 kA/m, respectively. Complex permeability of the composites decreased with an increase in frequency, and its real value (mu'r) had the maximum at about 0.3 GHz. The dielectric constants of the composites were epsilon'r = 6.7 and epsilon"r = 0.

  1. 77 FR 65651 - Determination of Attainment for the Chico Nonattainment Area for the 2006 Fine Particle Standard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-30

    ... Particle Standard; California; Determination Regarding Applicability of Clean Air Act Requirements AGENCY... Chico nonattainment area in California has attained the 2006 24-hour fine particle (PM 2.5 ) National... the 2006 24-hour NAAQS for fine particles (generally referring to particles less than or equal to 2.5...

  2. 78 FR 55225 - Determination of Attainment for the Chico Nonattainment Area for the 2006 Fine Particle Standard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-10

    ... Particle Standard; California; Determination Regarding Applicability of Clean Air Act Requirements AGENCY... the Chico nonattainment area in Butte County, California has attained the 2006 24-hour fine particle... fine particles (generally referring to particles less than or equal to 2.5 micrometers in diameter, PM...

  3. Relaxation process and ferromagnetic resonance investigation of ferrofluids with Mn-Zn and Mn-Fe mixed ferrite particles

    NASA Astrophysics Data System (ADS)

    Mălăescu, I.; Ştefu, N.; Gabor, L.

    2001-09-01

    The magnetic relaxation processes in two ferrofluids with Mn 0.4Zn 0.6Fe 2O 4 (sample F1) and Mn 0.6Fe 0.4Fe 2O 4 (sample F2) mixed ferrite particles, dispersed in n-decan and kerosene, respectively, are investigated through the determination of components χ' and χ'' of the complex magnetic susceptibility in the range of (2-30) MHz. The values of the saturation magnetization of the two ferrofluids are M∞=5.28 kA/m for sample F1 and M∞=10.99 kA/m for sample F2. A maximum of the imaginary component χ'' was observed for both samples at frequencies of tens MHz. This maximum was assigned to relaxation processes of Néel type. The effective anisotropy constant K of the particles from the studied samples was evaluated, using both static and dynamic measurements and the values were found to be K1=6.12×10 3 J m -3 for the ferrofluid F1, and K2=5.60×10 3 J m -3 for the ferrofluid F2. From ferromagnetic resonance measurements, and based on the theoretical values computed for the Lande factor ( g), the effective anisotropy constants for the mixed ferrite particles in the studied ferrofluids and the anisotropy field values were determined using a new method. The values obtained in this way for the anisotropy constants K1 and K2 are compared to the ones determined from magnetic relaxation measurements.

  4. Fine-particle filter prevents damage to vacuum pumps

    NASA Technical Reports Server (NTRS)

    Harlamert, P., Jr.

    1964-01-01

    A filter system for mechanical pumps is designed with a baffle assembly that rotates in a circulating oil bath which traps destructive particles. This prevents severe damage to the pump and is serviceable for long periods before it requires cleaning.

  5. Shock induced magnetic effects in fine particle iron dispersions

    NASA Technical Reports Server (NTRS)

    Wasilewski, P. J.

    1979-01-01

    Magnetic effects associated with shock induced transformation of fcc antiferromagnetic iron precipitates in polycrystalline copper disks at levels up to 5 GPa in weak magnetic fields (H not greater than 0.5 Oe) were investigated. The demagnetization and anisotropy associated with second order transition, the effects of plastic deformation in imparting magnetic anisotropy and magnetic hardening, and the influence of post shock thermal transients on magnetization associated with recovery, recrystallization and grain growth were studied. It was found that on the microsecond time scale of the shock induced first order transformation, the field sense is recorded in the transformed iron particles. For a given particle size the degree of transformation of fcc iron depends on the level of the shock. For a given shock level the resultant magnetic properties depend on the particle size distribution, with maximum effects noted in specimens with 400 to 600 A particles.

  6. SPECIATION OF GAS-PHASE AND FINE PARTICLE EMISSIONS FROM BURNING OF FOLIAR FUELS

    EPA Science Inventory

    Particle size distributions (10-1000 nm aerodynamic diameter), physical and chemical properties of fine particle matter (PM2.5) with aerodynamic diameter <2.5 micrometers, and gas-phase emissions from controlled open burning of assorted taxa were measured. Chemical speciation of ...

  7. Dissolution of fine and intermediate sized galena particles and their interactions with iron hydroxide colloids.

    PubMed

    Peng, Yongjun; Grano, Stephen

    2010-07-01

    Dissolution of fine (-10 microm) and intermediate (+10-53 microm) galena particles was studied in the presence and absence of iron hydroxide colloids at pH 9 with nitrogen and oxygen purging. X-ray photoelectron spectroscopy (XPS) measurements and ethylene diamine-tetra acid (EDTA) extraction of the galena particles after dissolution indicate that galena dissolution is strongly dependent on particle size. Fine galena particles produced a much higher amount of lead hydroxide species per surface area than intermediate galena particles. Gas purging only affected galena dissolution slightly. More iron hydroxide colloids adsorbed on fine particles. Zeta potential measurements indicate that galena dissolution enhances the adsorption of iron hydroxide colloids due to the electrostatic attraction between lead hydroxide products and iron hydroxide colloids at pH 9. This explains the stronger affinity of iron hydroxide colloids to fine galena particles than intermediate galena particles. This study has an important implication in sulfide flotation where iron hydroxide colloids play a dominant role in mineral depression.

  8. SPECIATION OF GAS-PHASE AND FINE PARTICLE EMISSIONS FROM BURNING OF FOLIAR FUELS

    EPA Science Inventory

    Particle size distributions (10-1000 nm aerodynamic diameter), physical and chemical properties of fine particle matter (PM2.5) with aerodynamic diameter <2.5 micrometers, and gas-phase emissions from controlled open burning of assorted taxa were measured. Chemical speciation of ...

  9. DIFFERENTIAL GENE EXPRESSION BY CHAPEL HILL FINE PARTICLES IN HUMAN ALVEOLAR MACHROPHAGES

    EPA Science Inventory

    Pollutant particles (PM) induce systemic and lung inflammation. Alveolar macrophages (AM) are one of the lung cells directly exposed to PM that may initiate these responses. In this study, we determined the gene expression profile induced by Chapel Hill fine particles (PM2.5) in ...

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

    EPA Science Inventory

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

  11. PERSONAL EXPOSURE TO FINE PARTICLE POLYCYCLIC AROMATIC HYDROCARBONS: OUTDOOR SOURCE TRACERS

    EPA Science Inventory


    The most carcinogenic and toxic polycyclic aromatic hydrocarbons (PAH) are the 4-5 ring PAH found preferentially adsorbed to the fine particles (<2.54u in urban ambient air and personal air. Personal exposure to the carcinogenic particle bound PAH is also highly correlated ...

  12. DIFFERENTIAL GENE EXPRESSION BY CHAPEL HILL FINE PARTICLES IN HUMAN ALVEOLAR MACHROPHAGES

    EPA Science Inventory

    Pollutant particles (PM) induce systemic and lung inflammation. Alveolar macrophages (AM) are one of the lung cells directly exposed to PM that may initiate these responses. In this study, we determined the gene expression profile induced by Chapel Hill fine particles (PM2.5) in ...

  13. Fine-Mode Marine Aerosol Composition over the Southern Ocean Exampled by Individual Particle Analysis

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Anderson, J. R.

    2012-12-01

    During a cruise in the Southern Ocean in the austral summer of 2010-2011, the fine-mode aerosol particles (0.1 - 1.0 microns in diameter) were collected on a transect from 55S, 94E to 69S, 76E to characterize marine aerosols, as aerosol particles in that size fraction may effectively serve as cloud condensation nuclei and scatter solar radiation in the marine atmospheric boundary layer. Analyses of individual aerosol particles were performed by automated scanning electron microscopy. Preliminary results indicate that the main components of the aerosol particles examined so far include sodium chloride, calcium sulfate and aluminum oxide (alumina), and the great majority of the particles consist of these components or mixtures of these components. A small percentage of fine particles were detected to have minor Fe. The aerosol samples collected appeared to be impacted by air masses from the Antarctic Peninsula and Patagonia. The presence of fine Al-rich particles suggests transport from a source or sources in Patagonia, such as the complex at Puerto Madryn, Argentina. The presence of Al of industrial origin (and the lack of Al-rich silicates from soil dust) in these fine particles is of interest, since its presence in aerosols is sometimes used as a marker for dust. The possible impact of anthropogenic pollutant aerosols on this remote oceanic region is also striking.

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

    EPA Science Inventory

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  16. Preparation of a melt-processed La123 bulk superconductor with finely dispersed Y211 particle

    NASA Astrophysics Data System (ADS)

    Hee-Gyoun Lee; Il-Hyun Kook; Gye-Won Hong; Kyu-Won Lee; Yong-Il Kim; Chang-Soo Kim; Jong-Jin Kim; Myoung-Youp Song

    1995-02-01

    A high-magnetization La123 specimen with finely dispersed second-phase particles was successfully fabricated by a melt process under a reduced oxygen partial pressure. The dispersion of the fine second-phase particle was obtained by adding Y211 particles to the La123 specimen. The melt-down and the crack propagation were effectively suppressed in a melt-processed specimen with Y211 addition. The magnetization of the La123 specimen was clearly enhanced with Y211 addition. It is considered that the Y211 addition introduced extra flux-pinning centers in the La123 specimen.

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

    NASA Astrophysics Data System (ADS)

    Dutt, Meenakshi; Elliott, James A.

    2009-06-01

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

  18. Experimental verification of interactions between randomly distributed fine magnetic particles

    NASA Astrophysics Data System (ADS)

    Taketomi, Susamu; Shull, Robert D.

    2003-10-01

    We experimentally examined whether or not a magnetic fluid (MF) is really superparamagnetic by comparing the initial magnetic susceptibilities of the mother MFs with those of their highly diluted solutions (more than 1000 times diluted) in which the dipole-dipole interaction between the particles was negligible. We used three mother MFs, SA 1, SB 1, and SC 1, and their highly diluted solutions, SA 2, SB 2, and SC 2, respectively. The particles' dispersability was best in SA 1 and poorest in SC 1. From the static field experiment, it was found that the mutual interaction between the particles in SB 1, and SC 1 made clusters of particles with magnetically closed flux circuits even at zero field while no interaction was detected in SA 1. The initial complex magnetic susceptibility, χ˜, as a function of temperature, T, under an AC field experiment revealed that the complex susceptibility of both the samples SA 1 and SA 2 showed peaks as a function of T. However, their χ˜ vs. T curves were not similar, leading to the conclusion that the sample SA 1 was not superparamagnetic. Instead, SA 1 was a magnetic spin-glass induced by the weak interaction between the particle spins. The existence of the spin-glass state was also confirmed by the Volgel-Fulcher law dependence of the AC-susceptibility peak temperature, Tp, or the frequency of the AC field.

  19. Sizing fine particles with the phase Doppler interferometric technique.

    PubMed

    Sankar, S V; Weber, B J; Kamemoto, D Y; Bachalo, W D

    1991-11-20

    A theoretical model based on the Lorenz-Mie theory was used to study the response characteristics of the Aerometrics phase Doppler particle analyzer (PDPA). The validity of the model was verified experimentally, and its suitability for calculating measurement uncertainties was established. The theoretical and experimental results suggest that size resolutions of the order of +/-0.3 microm are possible when the PDPA is used to measure small spherical particles (< 10 microm). We show that the optical configuration of the PDPA plays an important role in establishing the sizing uncertainty of the instrument.

  20. Growing Characteristics of Fine Ice Particles in Surfactant Solution

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiroshi; Nakayama, Kosuke; Komoda, Yoshiyuki; Usui, Hiromoto; Okada, Kazuto; Fujisawa, Ryo

    Time variation characteristics of ice particles in a surfactant solution have been investigated. The effect of surfactants on corrosion characteristics was also studied. The results were compared with those treated with poly(vinyl alcohol). From the results, the present surfactant, cetyl dimethyl betaine was not found to be effective on preventing Ostward ripening of ice particles as poly(vinyl alcohol) showed. Then, it was concluded some effective technology has to be installed with surfactants when this surfactant treatment is realized. On the corrosion characteristics, it was found that the present surfactant shows the same level as tap water.

  1. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 2, Single particle kinetic studies of sulfidation and regeneration reactions of candidate zinc ferrite sorbents

    SciTech Connect

    Silaban, A.; Harrison, D.P.

    1989-05-02

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  2. Pattern formation and flow control of fine particles by laser-scanning micromanipulation.

    PubMed

    Sasaki, K; Koshioka, M; Misawa, H; Kitamura, N; Masuhara, H

    1991-10-01

    A novel micromanipulation technique is proposed for aligning fine particles on micrometer-scale spatial patterns and for moving the particles continuously along the formed patterns. This technique is based on the repetitive scanning of a focused trapping laser beam. The velocity of the particle flow can be controlled by scan speed and laser power. The origin of the driving force is considered theoretically and experimentally.

  3. Design of grid-type microwave absorbers with high-permittivity composites of Ag-coated Ni-Zn ferrite particles

    NASA Astrophysics Data System (ADS)

    Cho, Han-Shin; Kim, Sung-Soo

    2015-05-01

    We investigate the microwave absorbing characteristics in grid-shaped rubber composite sheets containing Ag-coated Ni-Zn ferrite particles. The improvements in the microwave absorbance are obtained through the insertion of a periodic air cavity in the high-permittivity composites. In the bulk specimens containing conductive and magnetic Ag-coated ferrite microspheres, the impedance matching is not satisfied due to the high dielectric permittivity of the composite. The insertion of an air cavity in those absorbers reduces the permittivity and permeability, and thereby leading to impedance matching at a higher frequency. In the grid-type absorber with an optimum air cavity volume rate, the reflection loss can be decreased to as low as -30 dB at 10.5 GHz with a small layer thickness of 2 mm. The proposed grid-type microwave absorber has advantages of a small matching thickness and a considerable reduction in weight in comparison with conventional ferrite composite absorbers.

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

    NASA Technical Reports Server (NTRS)

    Baerns, M. G.; Ramaswami, D.

    1969-01-01

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

  5. Thermomagnetic stability of M-type strontium ferrite (SrFe12O19) particles with different shapes

    NASA Astrophysics Data System (ADS)

    Park, Jihoon; Hong, Yang-Ki; Lee, Woncheol; Kim, Chin-Mo; Choi, Kang-Ryong; An, Sung-Yong; Seo, Jung-Wook; Hur, Kang-Heon

    2016-01-01

    M-type strontium ferrite (SrFe12O19: SrM) with two different shapes were synthesized by a simple and benign process. One is peanut-like shape, and the other is hexagonal platelet. These shapes were controlled by the shape and size of precursor Fe3O4 particles. A mixture of submicron- or nanometer-sized Fe3O4 particles and SrCO3 nanoparticles was calcined to transform to SrM, followed by acid-washing to remove secondary phase from SrM particles. Static magnetic properties, magnetic interactions, and thermomagnetic stability of the SrM particles were studied. The measured saturation magnetization and intrinsic coercivity are 74.2 emu/g and 4431 Oe, respectively, for the peanut-like SrM particles and 73.6 emu/g and 5360 Oe for the hexagonal SrM platelets. The saturation magnetization is close to the theoretical value of 76 emu/g. Both types of SrM show dipolar interactions and good thermomagnetic stability, i.e. α = Δ σ s / σ s = -0.16%/K and β = Δ H ci/ H ci = 0.15%/K for the peanut-like SrM particles and α = -0.12%/K and β = 0.12%/K for the hexagonal SrM platelets. The temperature coefficient of intrinsic coercivity ( β) is positive and magnetization still remains high at 400 K; 60 emu/g for the hexagonal SrM platelets and 50 emu/g for the peanut-like SrM particles. [Figure not available: see fulltext.

  6. Effectiveness of initiating extrafine-particle versus fine-particle inhaled corticosteroids as asthma therapy in the Netherlands.

    PubMed

    van der Molen, Thys; Postma, Dirkje S; Martin, Richard J; Herings, Ron M C; Overbeek, Jetty A; Thomas, Victoria; Miglio, Cristiana; Dekhuijzen, Richard; Roche, Nicolas; Guilbert, Theresa; Israel, Elliot; van Aalderen, Wim; Hillyer, Elizabeth V; van Rysewyk, Simon; Price, David B

    2016-05-17

    Most randomised clinical trials typically exclude a significant proportion of asthma patients, including those at higher risk of adverse events, with comorbidities, obesity, poor inhaler technique and adherence, or smokers. However, these patients might differentially benefit from extrafine-particle inhaled corticosteroids (ICS). This matched cohort, database study, compared the effectiveness of extrafine-particle with fine-particle ICS in a real-life population initiating ICS therapy in the Netherlands. Data were from the Pharmo Database Network, comprising pharmacy and hospital discharge records, representative of 20 % of the Dutch population. The study population included patients aged 12 - 60, with a General Practice-recorded diagnosis for asthma (International Classification of Primary Care code R96), when available, ≥2 prescriptions for asthma therapy at any time in their recorded history, and receiving first prescription of ICS therapy as either extrafine-particle (ciclesonide or hydrofluoroalkane beclomethasone dipropionate [BDP]) or fine-particle ICS (fluticasone propionate or non-extrafine-particle-BDP). Patients were matched (1:1) on relevant demographic and clinical characteristics over 1-year baseline. Primary outcomes were severe exacerbation rates, risk domain asthma control and overall asthma control during the year following first ICS prescription. Secondary outcomes, treatment stability and being prescribed higher versus lower category of short-acting β2 agonists (SABA) dose, were compared over a 1-year outcome period using conditional logistic regression models. Following matching, 1399 patients were selected in each treatment cohort (median age: 43 years; males: 34 %). Median (interquartile range) initial ICS doses (fluticasone-equivalents in μg) were 160 (160 - 320) for extrafine-particle versus 500 (250 - 500) for fine-particle ICS (p < 0.001). Following adjustment for residual confounders, matched patients prescribed

  7. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    NASA Astrophysics Data System (ADS)

    Chen, Daming; Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (Tc). We prepared aluminum doped barium ferrite ceramics (BaAlxFe12-xO19, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate Tc and magnetic properties of BaFe12-xAlxO19. It is found that Tc decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πMs) decreases with increasing x, while the coercivity (Hc) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement.

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

    PubMed

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

    2014-01-30

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

  9. Selective separation of ultra-fine particles by magnetophoresis

    SciTech Connect

    Ying, T.; Prenger, F. Coyne; Wingo, R. M.; Worl, L. A.

    2002-01-01

    The selective and-specific extraction of species of interest fiom local environmental and other sample sources are importaut fbr scientific research, industrial processes, and environmental applications. A novel process for selective separation of ultrafine particles using 'magnetophoresis' is investigated. The principle of this process is that the direction and velocity of particle movement in a magnetic field are determined by magnetic, gravitational, and drag fbrces. By controlling these fbrces, one is able to control the migration rates of different species and then magnetically fiactionate mixtures of species into discrete groups. This study demonstrated for the fist time the selective separation of various species, such as iron (111) oxide, cupric (11) oxide, samarium (In) oxide, and cerium (III) oxide, by magnetophoresis. To better understand this phenomenon, a fbrce-balance model was developed that provides a good interpretation of the experimental results.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    PubMed

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

    2014-08-15

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

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

    NASA Astrophysics Data System (ADS)

    Niño-Martínez, N.; Martínez-Castañón, G. A.; Aragón-Piña, A.; Martínez-Gutierrez, F.; Martínez-Mendoza, J. R.; Ruiz, Facundo

    2008-02-01

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO2 particles using a simple aqueous reduction method. The reducing agent used was NaBH4; different molar ratios TiO2:Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO2 particles and that the TiO2:Ag molar ratio plays an important role. We used three different TiO2Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO2 particles.

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

    PubMed

    Niño-Martínez, N; Martínez-Castañón, G A; Aragón-Piña, A; Martínez-Gutierrez, F; Martínez-Mendoza, J R; Ruiz, Facundo

    2008-02-13

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

    The purpose of the present study was to evaluate six nitro-polycyclic aromatic hydrocarbons (NPAHs) in fine (< 2.5 μm) and coarse (2.5-10 μm) atmospheric particles in an urban and industrial area located in the Metropolitan Area of Porto Alegre (MAPA), RS, Brazil. The method used was of NPAHs isolation and derivatization, and subsequent gas chromatography by electron capture detection (CG/ECD). Results revealed a higher concentration of NPAHs, especially 3-nitrofluoranthene and 1-nitropyrene, in fine particles in the sampling sites studied within the MAPA. The diagnostic ratios calculated for PAHs and NPAHs identified the influence of heavy traffic, mainly of diesel emissions. The correlation of NPAHs with other pollutants (NO x, NO 2, NO and O 3) evidence the influence of vehicular emissions in the MAPA. The seasonal variation evidenced higher NPAHs concentrations in the fine particles during winter for most compounds studied.

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

    PubMed Central

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

    2017-01-01

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

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

    PubMed Central

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

    2014-01-01

    We study the packing of fine glass powders of mean particle diameter in the range (4–52) μm both experimentally and by numerical DEM simulations. We obtain quantitative agreement between the experimental and numerical results, if both types of attractive forces of particle interaction, adhesion and non-bonded van der Waals forces are taken into account. Our results suggest that considering only viscoelastic and adhesive forces in DEM simulations may lead to incorrect numerical predictions of the behavior of fine powders. Based on the results from simulations and experiments, we propose a mathematical expression to estimate the packing fraction of fine polydisperse powders as a function of the average particle size. PMID:25178812

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

    PubMed

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

    2014-09-02

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

  19. The ozonolysis of primary aliphatic amines in fine particles

    NASA Astrophysics Data System (ADS)

    Zahardis, J.; Geddes, S.; Petrucci, G. A.

    2008-02-01

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

  20. Temporal structure of gas temperature fluctuations and ignition of fine particles

    NASA Astrophysics Data System (ADS)

    Derevich, I. V.; Galdina, D. D.

    2016-11-01

    The paper studies ignition of fine particles, i.e., irreversible growth of particle temperature from an exothermal heterogeneous reaction, with the rate approximated with the Arrhenius law. The particles are suspended in gas with fluctuating temperature, and heat transfer from the particle surface occurs according to the Newtonian law. The equations take into account the temporal structure of gas temperature fluctuations. Modern methods of functional analysis were applied for deriving a closed equation for the probability density function for the particle temperature distribution. The gas temperature fluctuations lessen the threshold for the particle ignition in the hot gas as compared with the deterministic variant. The equations for probability density function produce a closed system of conjugate equations for the average temperature and dispersion of particle temperature fluctuations. The results of simulation illustrate the phenomenon of self-speeding drift of particle temperature towards the temperature of ignition startup.

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  3. Source apportionment of urban fine and ultra-fine particle number concentration in a Western Mediterranean city

    NASA Astrophysics Data System (ADS)

    Pey, Jorge; Querol, Xavier; Alastuey, Andrés; Rodríguez, Sergio; Putaud, Jean Philippe; Van Dingenen, Rita

    Extensive measurements on particle number concentration and size distribution (13-800 nm), together with detailed chemical composition of PM 2.5 have constituted the main inputs of the database used for a source apportionment analysis. Data were collected at an urban background site in Barcelona, Western Mediterranean. The source identification analysis helped us to distinguish five emission sources (vehicle exhausts, mineral dust, sea spray, industrial source and fuel-oil combustion) and two atmospheric processes (photochemical induced nucleation and regional/urban background particles derived from coagulation and condensation processes). After that, a multilinear regression analysis was applied in order to quantify the contribution of each factor. This study reveals that vehicle exhausts contribute dominantly to the number concentration in all the particle sizes (52-86%), but especially in the range 30-200 nm. This work also points out the importance of the regional and/or urban formed aerosols (secondary inorganic particles) on the total number concentration (around 25% of the total number), with a higher impact on the accumulation mode. The photo-chemically induced nucleation of aerosols only represents a small proportion of the total number as an annual mean (3%), but is very relevant when considering only the nucleation mode (13-20 nm) fraction (23%). The other sources recognized registered sporadic contributions to the total number, coinciding with specific meteorological scenarios. This study discloses the main sources and features affecting and controlling the fine and ultra-fine aerosols in a typical city in the Western Mediterranean coast. Whereas the road traffic appears to be the most important source of sub-micrometric aerosols, other sources may not be negligible under specific meteorological conditions.

  4. Preparation of medical magnetic nanobeads with ferrite particles encapsulated in a polyglycidyl methacrylate (GMA) for bioscreening

    SciTech Connect

    Nishibiraki, H.; Kuroda, C.S.; Maeda, M.; Matsushita, N.; Abe, M.; Handa, H.

    2005-05-15

    Ferrite nanoparticles (an intermediate between Fe{sub 3}O{sub 4} and {gamma}-Fe{sub 2}O{sub 3}), {approx}7 nm in diameter, were embedded in beads of a mixed polymer of styrene (St) and glycidyl methacrylate (GMA) by emulsifier-free emulsion polymerization method. The beads were coated with GMA by a seeded polymerization method in order to suppress nonspecific protein binding on the surfaces; GMA exhibits very low nonspecific protein binding, which is required for carriers used for bioscreening. The beads have diameters of 180{+-}50 nm and saturation magnetizations of 28 emu/g, exceeding commercially available polymer-coated beads of micron size having a weaker saturation magnetization ({approx}12 emu/g)

  5. Curing properties of furfuryl alcohol condensate with carbonaceous fine particles under ultrasonication.

    PubMed

    Hoshi, K; Akatsu, T; Tanabe, Y; Yasuda, E

    2001-04-01

    Ultrasonic treatment (sonication) was carried out through the curing process of furan resin by using an ultrasonic homogenizer at the frequency of 20 kHz and the various intensities (0-90 W). Various carbonaceous fine particles were added to furan resin to investigate the change of polymerization degree. The curing rate of furan resin was accelerated by sonication, which increased the polymerization degree with an increase in ultrasound intensity. The increase of curing rate was also observed by small additions of carbonaceous fine particles. In this case, the curing rate was increased with an increase in the specific surface area on additives.

  6. Fine particle receptor modeling in the atmosphere of Mexico City.

    PubMed

    Vega, Elizabeth; Lowenthal, Douglas; Ruiz, Hugo; Reyes, Elizabeth; Watson, John G; Chow, Judith C; Viana, Mar; Querol, Xavier; Alastuey, Andrés

    2009-12-01

    Source apportionment analyses were carried out by means of receptor modeling techniques to determine the contribution of major fine particulate matter (PM2.5) sources found at six sites in Mexico City. Thirty-six source profiles were determined within Mexico City to establish the fingerprints of particulate matter sources. Additionally, the profiles under the same source category were averaged using cluster analysis and the fingerprints of 10 sources were included. Before application of the chemical mass balance (CMB), several tests were carried out to determine the best combination of source profiles and species used for the fitting. CMB results showed significant spatial variations in source contributions among the six sites that are influenced by local soil types and land use. On average, 24-hr PM2.5 concentrations were dominated by mobile source emissions (45%), followed by secondary inorganic aerosols (16%) and geological material (17%). Industrial emissions representing oil combustion and incineration contributed less than 5%, and their contribution was higher at the industrial areas of Tlalnepantla (11%) and Xalostoc (8%). Other sources such as cooking, biomass burning, and oil fuel combustion were identified at lower levels. A second receptor model (principal component analysis, [PCA]) was subsequently applied to three of the monitoring sites for comparison purposes. Although differences were obtained between source contributions, results evidence the advantages of the combined use of different receptor modeling techniques for source apportionment, given the complementary nature of their results. Further research is needed in this direction to reach a better agreement between the estimated source contributions to the particulate matter mass.

  7. Magnetic and structural properties of nanosize Ni Zn Cr ferrite particles synthesized by combustion reaction

    NASA Astrophysics Data System (ADS)

    Gama, L.; Hernandez, E. P.; Cornejo, D. R.; Costa, A. A.; Rezende, S. M.; Kiminami, R. H. G. A.; Costa, A. C. F. M.

    2007-10-01

    This paper reports on Cr 3+-doped and undoped Ni-Zn nanosize ferrite obtained by reaction combustion synthesis. The powders resulting from this synthesis were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and their magnetic properties examined with an alternative gradient magnetometer (AGM) and by ferromagnetic resonance (FMR). The XRD results confirmed the formation of Ni 0.5Zn 0.5Fe 2O 4 bulk spinel and small quantities of second phase hematite (αFe 2O 4) to the powders without chromium. However, the powders containing 0.1 mol of chromium showed only a Ni-Zn ferrite cubic phase. The Ni 0.5Zn 0.5Fe 2O 4 and Ni 0.5Zn 0.5Fe 1.9Cr 0.1O 4 showed average crystallite sizes of 20.7 and 22.7 nm, respectively. The SEM micrographs of the powders to the sample without chromium reveals nanoparticles with a regular morphology without pre-sintering and with the presence of soft agglomerations. The powder with 0.1 mol of chromium displays homogeneous and finer nanoparticles, which are more reactive and hence more agglomerated. Saturation magnetization of the phase without Cr 3+ was 61.97 emu/g, while that of the powder with chromium was 40.56 emu/g. The inclusion of chromium caused the magnetization index to drop by 34% and decreased the coercive field, Hc, by 77%. It is known that the inclusion of chromium is advantageous for high-frequency transformer applications.

  8. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  9. The mechanisms of fine particle generation and electrification during Mount St. Helens volcanic eruption

    NASA Technical Reports Server (NTRS)

    Cheng, R. J.

    1982-01-01

    Microscopical investigation of volcanic ash collected from ground stations during Mount St. Helens eruptions reveal a distinctive bimodel size distribution with high concentrations of particle ranges at (1) 200-100 microns and (2) 20-0.1 microns. Close examination of individual particles shows that most larger ones are solidified magma particles of porous pumice with numerous gas bubbles in the interior and the smaller ones are all glassy fragments without any detectable gas bubbles. Elemental analysis demonstrates that the fine fragments all have a composition similar to that of the larger pumice particles. Laboratory experiments suggest that the formation of the fine fragments is by bursting of glassy bubbles from a partially solidified surface of a crystallizing molten magma particle. The production of gas bubbles is due to the release of absorbed gases in molten magma particles when solubility decreases during phase transition. Diffusion cloud chamber experiments strongly indicate that sub-micron volcanic fragments are highly hygroscopic and extremely active as cloud condensation nuclei. Ice crystals also are evidently formed on those fragments in a supercooled (-20 C) cloud chamber. It has been reported that charge generation from ocean volcanic eruptions is due to contact of molten lava with sea water. This seems to be insufficient to explain the observed rapid and intense lightning activities over Mount St. Helens eruptions. Therefore, a hypothesis is presented here that highly electrically charged fine solid fragments are ejected by bursting of gas bubbles from the surface of a crystallizing molten magma particles.

  10. Nasal contribution to breathing and fine particle deposition in children versus adults.

    PubMed

    Bennett, William D; Zeman, Kirby L; Jarabek, Annie M

    2008-01-01

    Both the route of breathing, nasal versus oral, and the effectiveness of the nose to filter inhaled, fine particles may differ between children and adults. This study compared (1) the nasal contribution to breathing at rest and during mild to moderate exercise in children (age 6-10 yr) versus young adults and (2) the nasal deposition efficiency (NDE) of fine particles (1 and 2 microm MMAD, GSD < 1.2) under resting and light exercise breathing conditions in the same children and adults. Nasal contribution to breathing was assessed by respiratory inductance plethysmography and a nasal mask with flow meter during incremental exercise on a bicycle ergometer. Fine particle deposition fractions for nasal and oral breathing were assessed by inhalation of monodisperse carnauba wax particles and laser photometry to determine inhaled/exhaled concentrations. There was a trend for children to have a lesser nasal contribution to breathing at rest and during exercise, but the differences from adults were not statistically significant. Children did, however, have significantly decreased NDE for 2-microm particles under light exercise breathing conditions compared to adults, suggesting less efficient nasal filtering for larger particles and higher flow conditions. These results suggest that the lungs of children may be exposed to higher concentrations of inhaled, ambient particles than adults.

  11. Magnetic fine particles of Fe and Co encapsulated by carbon layers

    NASA Astrophysics Data System (ADS)

    Tokoro, Hisato; Fujii, Shigeo; Oku, Takeo

    2005-04-01

    Fine particles of Fe and Co encapsulated by carbon (C) nanolayers were synthesized through reduction of the metal oxides by C. They were ∼400 nm in diameter, and the shell of the C layers was ∼5 nm in thickness. The Fe particles were composed of mixture of body-centered cubic (BCC), α , and face-centered cubic (FCC), γ -phase, and the Co particles were composed of a FCC, α -phase. Maximum saturation magnetization of the Fe was 101 Am2/kg and that of the Co was 136 Am2/kg. Those C-encapsulated particles showed excellent soft magnetic properties and oxidation resistance in air.

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

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

  13. Enhancing the linear flow of fine granules through the addition of elongated particles

    PubMed Central

    Guo, Zhiguo; Chen, Xueli; Xu, Yang; Liu, Haifeng

    2015-01-01

    Sandglasses have been used to record time for thousands of years because of their constant flow rates; however, they now are drawing attention for their substantial scientific importance and extensive industrial applications. The presence of elongated particles in a binary granular system is believed to result in undesired flow because their shape implies a larger resistance to flow. However, our experiments demonstrate that the addition of elongated particles can substantially reduce the flow fluctuation of fine granules and produce a stable linear flow similar to that in an hourglass. On the basis of experimental data and previous reports of flow dynamics, we observed that the linear flow is driven by the “needle particle effect,” including flow orientation, reduced agglomeration, and local perturbation. This phenomenon is observed in several binary granular systems, including fine granules and secondary elongated particles, which demonstrates that our simple method can be widely applied to the accurate measurement of granular flows in industry. PMID:26551736

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

    USGS Publications Warehouse

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    PubMed

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

    2012-07-01

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

  17. Spatial variability of fine particle concentrations in three European areas

    NASA Astrophysics Data System (ADS)

    Hoek, Gerard; Meliefste, Kees; Cyrys, Josef; Lewné, Marie; Bellander, Tom; Brauer, Mike; Fischer, Paul; Gehring, Ulrike; Heinrich, Joachim; van Vliet, Patricia; Brunekreef, Bert

    Epidemiological studies of long-term air pollution effects have been hampered by difficulties in characterizing the spatial variation in air pollution. We conducted a study to assess the risk of long-term exposure to traffic-related air pollution for the development of inhalant allergy and asthma in children in Stockholm county, Munich and the Netherlands. Exposure to traffic-related air pollution was assessed through a 1-year monitoring program and regression modeling using exposure indicators. This paper documents the performance of the exposure monitoring strategy and the spatial variation of ambient particle concentrations. We measured the ambient concentration of PM2.5 and the reflectance of PM2.5 filters ('soot') at 40-42 sites representative of different exposure conditions of the three study populations. Each site was measured during four 14-day average sampling periods spread over one year (spring 1999 to summer 2000). In each study area, a continuous measurement site was operated to remove potential bias due to temporal variation. The selected approach was an efficient method to characterize spatial differences in annual average concentration between a large number of sites in each study area. Adjustment with data from the continuous measurement site improved the precision of the calculated annual averages, especially for PM2.5. Annual average PM2.5 concentrations ranged from 11 to 20 μg/m 3 in Munich, from 8 to 16 μg/m 3 in Stockholm and from 14 to 26 μg/m 3 in the Netherlands. Larger spatial contrasts were found for the absorption coefficient of PM2.5. PM2.5 concentrations were on average 17-18% higher at traffic sites than at urban background sites, but PM2.5 absorption coefficients at traffic sites were between 31% and 55% increased above background. This suggests that spatial variation of traffic-related air pollution may be underestimated if PM2.5 only is measured.

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

    PubMed

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

    2009-04-15

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

  19. Evaluation of an abbreviated impactor for fine particle fraction (FPF) determination of metered dose inhalers (MDI).

    PubMed

    Guo, Changning; Ngo, Diem; Ahadi, Shafiq; Doub, William H

    2013-09-01

    Abbreviated impactors have been developed recently to allow more rapid evaluation of inhalation products as alternates to the eight-stage Andersen Cascade Impactor (ACI) which has been widely used in the pharmaceutical industry for assessing aerodynamic particle size distribution. In this paper, a two-stage abbreviated impactor, Westech Fine Particle Dose Impactor (WFPD), was used to characterize the aerodynamic particle size of metered dose inhaler (MDI) products, and the results were compared with those obtained using the standard eight-stage ACI. Seven commercial MDI products, with different propellants (chlorofluorocarbon/hydrofluoroalkane) and formulation types (suspension/solution, dry/normal/wet), were tested in this study by both WFPD and ACI. Substantially equivalent measures of fine particle fraction were obtained for most of the tested MDI products, but larger coarse particle fraction and extra-fine particle fraction values were measured from WFPD relative to those measured using the ACI. Use of the WFPD also produced more wall loss than the ACI. Therefore, it is recommended that the system suitability be evaluated on a product-by-product basis to establish substantial equivalency before implementing an abbreviated impactor measurement methodology for routine use in inhaler product characterization.

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

    PubMed

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

    2017-01-01

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

  1. 40 CFR 52.131 - Control Strategy and regulations: Fine Particle Matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.131 Section 52.131 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Arizona § 52.131 Control...

  2. 40 CFR 52.131 - Control Strategy and regulations: Fine Particle Matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control Strategy and regulations: Fine Particle Matter. 52.131 Section 52.131 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Arizona § 52.131 Control...

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

    EPA Science Inventory

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

  4. The path toward clean air: implementing new standards for ozone and fine particles

    SciTech Connect

    Lydia Wegman; Erika Sasser

    2005-04-01

    Many areas in the United States have air pollution that exceeds the levels allowed by the U.S. Environmental Protection Agency (EPA) under its revised National Ambient Air Quality Standards for ozone and fine particles. This article provides an overview of the steps EPA and states are taking to implement the new standards. 17 refs., 3 figs., 2 tabs.

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

    EPA Science Inventory

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

  6. 76 FR 14812 - Additional Air Quality Designations for the 2006 24-Hour Fine Particle National Ambient Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... Particle National Ambient Air Quality Standards, 110(k)(6) Correction and Technical Correction Related to... the Annual Fine Particles National Ambient Air Quality Standards Correction In rule document 2011-2269...

  7. Nano-scale nitride-particle-strengthened high-temperature wrought ferritic and martensitic steels

    SciTech Connect

    Klueh, Ronald L; Hashimoto, Naoyuki; Maziasz, Philip J

    2009-04-21

    A method of making a steel composition includes the steps of: a. providing a steel composition that includes up to 15% Cr, up to 3% Mo, up to 4% W, 0.05-1% V, up to 2% Si, up to 3% Mn, up to 10% Co, up to 3% Cu, up to 5% Ni, up to 0.3% C, 0.02-0.3% N, balance iron, wherein the percentages are by total weight of the composition; b. austenitizing the composition at a temperature in the range of 1000.degree. C. to 1400.degree. C.; c. cooling the composition of steel to a selected hot-working temperature in the range 500.degree. C. to 1000.degree. C.; d. hot-working the composition at the selected hot-working temperature; e. annealing the composition for a time period of up to 10 hours at a temperature in the range of 500.degree. C. to 1000.degree. C.; and f. cooling the composition to ambient temperature to transform the steel composition to martensite, bainite, ferrite, or a combination of those microstructures.

  8. Comparative risk analysis of dioxins in fish and fine particles from heavy-duty vehicles.

    PubMed

    Leino, Olli; Tainio, Marko; Tuomisto, Jouni T

    2008-02-01

    Dioxins and airborne fine particles are both environmental health problems that have been the subject of active public debate. Knowledge on fine particles has increased substantially during the last 10 years, and even the current, lowered levels in the Europe and in the United States appear to be a major public health problem. On the other hand, dioxins are ubiquitous persistent contaminants, some being carcinogens at high doses, and therefore of great concern. Our aim was to (a) quantitatively analyze the two pollutant health risks and (b) study the changes in risk in view of the current and forthcoming EU legislations on pollutants. We performed a comparative risk assessment for both pollutants in the Helsinki metropolitan area (Finland) and estimated the health effects with several scenarios. For primary fine particles: a comparison between the present emission situation for heavy-duty vehicles and the new fine particle emission standards set by the EU. For dioxins: an EU directive that regulates commercial fishing of Baltic salmon and herring that exceed the dioxin concentration limit set for fish meat, and a derogation (= exemption) from the directive for these two species. Both of these two decisions are very topical issues and this study estimates the expected changes in health effects due to these regulations. It was found that the estimated fine particle risk clearly outweighed the estimated dioxin risk. A substantial improvement to public health could be achieved by initiating reductions in emission standards; about 30 avoided premature deaths annually in the study area. In addition, the benefits of fish consumption due to omega-3 exposure were notably higher than the potential dioxin cancer risk. Both regulations were instigated as ways of promoting public health.

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

    PubMed Central

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-01-01

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

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

    PubMed

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-08-10

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

  11. Spectroscopy of peaks at microwave range for nanostructure SrFe12O19 and NiFe2O4 ferrite particles

    NASA Astrophysics Data System (ADS)

    Ariaee, Sina; Mehdipour, Mostafa; Moradnia, Mina

    2017-05-01

    In this paper, (SrFe12O19 and NiFe2O4) nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts utilizing the sodium hydroxide solution. The resulting precursors were heat-treated at 1100 °C for 4 h. After cooling in the furnace, the ferrite powders were pressed at 0.1 MPa and then sintered at 1200 °C for 4 h. The spectroscopy and characterization of peaks at the microwave range (X-band) for the nanostructure ferrite particles were investigated by the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. The extracted data from these theoretical and experimental results showed that the natural ferromagnetic resonance can be lead to the narrow peaks and the width of the peaks can be related to the periodic effects. Two kinds of peaks were seen for NiFe2O4 at X-band (8-12 GHz); the narrow peak at (9.8 GHz) was remaining unchanged and consistent while the wide one was shifted from 11 GHz to 8.5 GHz by decreasing the thickness of the samples. These phenomena were also happened for SrFe12O19 samples. The natural resonance was not happened due to the hard magnetic properties of these nano structure particles.

  12. Precipitates and Particles Coarsening of 9Cr-1.7W-0.4Mo-Co Ferritic Heat-Resistant Steel after Isothermal Aging.

    PubMed

    Gao, Qiuzhi; Zhang, Yanan; Zhang, Hailian; Li, Huijun; Qu, Fu; Han, Jian; Lu, Cheng; Wu, Bintao; Lu, Yao; Ma, Yan

    2017-07-19

    The precipitates obtained by EPE technology from the 9Cr-1.7W-0.4Mo-Co ferritic heat-resistant steel subject to isothermal aging were investigated using SEM, TEM and XRD. The particle size distribution and the coarsening kinetics of M23C6 with duration of isothermal aging were also analyzed with or without consideration of Laves phase. The results show that the isolated dislocations were detected in delta ferrite interior, and the precipitates on delta ferrite and martensite boundaries are obviously larger than other locations. Fe2W-Laves phase can only be found as duration of aging time to 2000 h, and is preferential to form adjacent to M23C6 particles. The small M23C6 particles firstly coarsen, but the large M23C6 are relatively stable during short aging. The total coarsening rate of M23C6 precipitates is 9.75 × 10(-28)m(3)s(-1), and the coarsening of M23C6 depends on the formation of Laves phase.

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

    SciTech Connect

    Misra, Shikha; Mishra, S. K.

    2015-02-15

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

  14. Mineralogical characterization of ambient fine/ultrafine particles emitted from Xuanwei C1 coal combustion

    NASA Astrophysics Data System (ADS)

    Lu, Senlin; Hao, Xiaojie; Liu, Dingyu; Wang, Qiangxiang; Zhang, Wenchao; Liu, Pinwei; Zhang, Rongci; Yu, Shang; Pan, Ruiqi; Wu, Minghong; Yonemochi, Shinich; Wang, Qingyue

    2016-03-01

    Nano-quartz in Xuanwei coal, the uppermost Permian (C1) coal deposited in the northwest of Yuanan, China, has been regarded as one of factors which caused high lung cancer incidence in the local residents. However, mineralogical characterization of the fine/ultrafine particles emitted from Xuanwei coal combustion has not previously been studied. In this study, PM1 and ultrafine particles emitted from Xuanwei coal combustion were sampled. Chemical elements in the ambient particles were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and mineralogical characterization of these ambient particles was investigated using scanning electronic microscopy (SEM/EDX) and transmission electronic microscopy, coupled with energy-dispersive spectroscopy (TEM/EDX). Our results showed that the size distribution of mineral particles from the coal combustion emissions ranged from 20 to 200 nm. Si-containing particles and Fe-containing particles accounted for 50.7% of the 150 individual particles measured, suggesting that these two types of particles were major minerals in the ambient particles generally. The nano-mineral particles were identified as quartz (SiO2) and gypsum (CaSO4) based on their crystal parameters and chemical elements. Additionally, there also existed unidentified nano-minerals. Armed with these data, toxicity assessments of the nano-minerals will be carried out in a future study.

  15. Fine particles that adsorb lipopolysaccharide via bridging calcium cations may mimic bacterial pathogenicity towards cells.

    PubMed

    Ashwood, Paul; Thompson, Richard P H; Powell, Jonathan J

    2007-01-01

    Fine particles (10(2)- to 10(3)-nm diameter) are potentially potent adjuvants in acquired immune responses but little is known about their interaction with pathogen-associated molecular patterns (PAMPs) and impact upon innate immunity. Here we show that 200-nm-sized, food-grade titanium dioxide avidly binds lipopolysaccharide (LPS) with bridging calcium cations, and the complex induces marked proinflammatory signalling in primary human mononuclear phagocytes. In particular, caspase 1-dependent interleukin-1beta (IL-1beta) secretion was induced at levels far greater than for the sum of the individual components, and without concomitant secretion of modulatory cytokines such as interleukin-1 receptor antagonist or transforming growth factor-beta1 (TGF-beta1). Secondly, the conjugate induced apoptotic-like cell death. These responses were inhibited by blockade of both phagocytosis and scavenger receptor uptake. Specific caspase 1-facilitated IL-1beta secretion and apoptosis following phagocytosis are features of cellular responses to certain invasive, enteric pathogens, and hence induction of these events may be mimicked by fine particle-LPS conjugates. The inadvertent adsorption of PAMPs to ingested, inhaled, or "wear" fine particulate matter provides a further potential mechanism for the proinflammatory nature of fine particles.

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

    PubMed

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

    2013-09-10

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

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

    NASA Astrophysics Data System (ADS)

    Solonenko, O. P.

    2012-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Lalak, Zygmunt; Lewicki, Marek

    2013-05-01

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

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

    SciTech Connect

    Watson, J.H.P.

    1995-02-01

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

  20. A comparative study on the varying exposure to atmospheric fine and coarse particles under urban and rural conditions.

    PubMed

    Wolf-Benning, Uta; Schultz, Eckart; Dietze, Volker; Kaminski, Uwe; Endlicher, Wilfried

    2012-11-01

    This paper is based on the results of three air quality studies conducted in Buenos Aires in Berlin, and in German spas between 2003 and 2007. A high comparability of results was ensured by using the same sampling techniques and analytical methods. Total particle sampling was achieved by active sampling of fine (PM2.5) and passive sampling of coarse particles > or = 2.5 microm and giant particles > or = 10 microm. The highly absorbing, black, predominantly carbonaceous particles (BC) of fine particle samples were determined by measuring the total light attenuation of filter samples and interpreting the extinction value as black carbon. The difference between the gravimetric total mass concentration of the PM2.5 samples and the BC is defined as the transparent, mostly mineral fine fraction. In coarse/giant particle samples the mean gray value was determined by means of automated light microscopy with subsequent single-particle analysis. "Opaque" particles were separated from the "transparent" particle fraction by applying a grey value threshold level. Microscopic measurement of individual particles was employed to establish the size distribution of the coarse and giant fraction. Due to different health effects, the separate detection of these components is suggested. Decline functions of particles are given, possibly providing useful information for a more detailed specification of the local particle distribution, and for a better estimate of the individual exposure. Atmospheric dispersal of particles was found effected mainly by source characteristics. An increased, spatially largely constant level of fine transparent particles in Berlin indicates a particle plume originating from photochemical processes. Buenos Aires, in contrast, is characterized by a lower background level of fine transparent particles but is considerably affected by fine black particles from diesel emissions and by a higher resuspension of coarse/giant transparent, mainly soil particles.

  1. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  2. Magnetization of sol gel prepared zinc ferrite nanoparticles: Effects of inversion and particle size

    NASA Astrophysics Data System (ADS)

    Atif, M.; Hasanain, S. K.; Nadeem, M.

    2006-05-01

    Nanoparticles of ZnFe 2O 4 have been prepared by using sol-gel method in two different mediums (acidic and basic) in order to observe the influence of the medium on the magnetic properties of the obtained nanoparticles. X-ray diffraction and Mössbauer studies of these samples show the presence of single-phase spinel structure. The average size of the particles as determined by X-ray diffraction increases with the annealing temperature from 18 to 52 nm. With the increase in particle size, magnetization decreases while the magnetization blocking temperature increases. Magnetization studies show that the samples prepared in basic medium have more ferrimagnetic nature as compared to those prepared in acidic medium. We understand this increase in magnetization as reflective of the increased degree of inversion (transfer of Fe 3+ ions from octahedral to tetrahedral sites) in the particles of smaller size unit cells. From lattice parameter calculations on different particles it is determined that inversion is more favorable in the particles prepared in a basic medium than in the acidic medium due to the smaller cell size in the former.

  3. Modeled deposition of fine particles in human airway in Beijing, China

    NASA Astrophysics Data System (ADS)

    Li, Xiaoying; Yan, Caiqing; Patterson, Regan F.; Zhu, Yujiao; Yao, Xiaohong; Zhu, Yifang; Ma, Shexia; Qiu, Xinghua; Zhu, Tong; Zheng, Mei

    2016-01-01

    This study aims to simulate depositions of size-segregated particles in human airway in Beijing, China during seasons when fine particulate matter concentrations are high (December 2011 and April 2012). Particle size distributions (5.6-560 nm, electrical mobility diameter) near a major road in Beijing were measured by the TSI Fast Mobility Particle Sizer (FMPS). The information of size distributions provided by FMPS was applied in the Multiple-Path Particle Dosimetry model (MPPD) to quantify number and mass depositions of particles in human airway including extrathoracic (ET), tracheobronchial (TB), and pulmonary (PUL) regions of exposed Chinese in Beijing. Our results show that under ambient conditions, particle number concentration (NC) deposition in PUL is the highest in the three major regions of human airway. The total particle NC deposition in human airway in winter is higher than that in spring, especially for ultrafine particles (1.8 times higher) while particle mass concentration (MC) deposition is higher in spring. Although particle MC in clean days are much lower than that in heavily polluted days, total particle NC deposition in human airway in clean days is comparable to that in heavily polluted days. NC deposition for nucleation mode particles (10-20 nm, aerodynamic diameter) in clean days is higher than that in heavily polluted days. MC deposition for accumulation mode particles (100-641 nm, aerodynamic diameter) in heavily polluted days is much higher than that in clean days, while that of nucleation mode is negligible. The temporal variation shows that the arithmetic mean and the median values of particle NC and MC depositions in the evening are both the highest, followed by morning and noon, and it is most likely due to increased contribution from traffic emissions.

  4. XMCD and XMCD-PEEM Studies on Magnetic-Field-Assisted Self-Assembled 1D Nanochains of Spherical Ferrite Particles

    DOE PAGES

    Zhang, Wen; Wong, Ping Kwan Johnny; Zhang, Dong; ...

    2017-05-30

    Quasi-1D nanochains of spherical magnetic ferrite particles with a homogeneous particle size of ≈200 nm and a micrometer-sized chain length are fabricated in this paper via a self-assembly method under an external magnetic field. This assisting magnetic field (Hassist), applied during synthesis, significantly modifies the distribution of the Fe2+Oh, Fe3+Td, and Fe3+Oh cations in the chains, as demonstrated by X-ray magnetic circular dichroism (XMCD) combined with theoretical analysis. This provides direct evidence of the nontrivial role of external synthetic conditions for defining the crystal chemistry of nanoscale ferrites and in turn their magnetic properties, providing an extra degree of freedommore » for intentional control over the performances of 1D magnetic nanodevices for various applications. Magnetic imaging, performed via XMCD in photoemission electron microscopy, further shows the possibility of creating and trapping a series of adjacent magnetic domain walls in a single chain, suggesting that there is great application potential for these nanochains in 1D magnetic nanodevices, as determined by field- or current-driven domain wall motions. Finally, practical control over the magnetic properties of the nanochains is also achieved by extrinsic dopants of cobalt and zinc, which are observed to occupy the ferrite ionic sites in a selective manner.« less

  5. Surface-level fine particle mass concentrations: from hemispheric distributions to megacity sources.

    PubMed

    Hidy, George M

    2009-07-01

    Since 1990, basic knowledge of the "chemical climate" of fine particles, has greatly improved from Junge's compilation from the 1960s. A worldwide baseline distribution of fine particle concentrations on a synoptic scale of approximately 1000 km can be estimated at least qualitatively from measurements. A geographical distribution of fine particle characteristics is deduced from a synthesis of a variety of disparate data collected at ground level on all continents, especially in the northern hemisphere. On the average, the regional mass concentrations range from 1 to 80 microg/m3, with the highest concentrations in regions of high population density and industrialization. Fine particles by mass on a continental and hemispheric spatial scale are generally dominated by non-sea salt sulfate (0.2 to approximately 20 microg/m3, or approximately 25%) and organic carbon (0.2-> 10 microg/m3, or approximately 25%), with lesser contributions of ammonium, nitrate, elemental carbon, and elements found in sea salt or soil dust. The crustal and trace metal elements contribute a varied amount to fine particle mass depending on location, with a larger contribution in marine conditions or during certain events such as dust storms or volcanic disturbances. The average distribution of mass concentration and major components depends on the proximity to areal aggregations of sources, most of which are continental in origin, with contributions from sea salt emissions in the marine environment. The highest concentrations generally are within or near very large population and industrial centers, especially in Asia, including parts of China and India, as well as North America and Europe. Natural sources of blowing dust, sea salt, and wildfires contribute to large, intermittent spatial-scale particle loadings beyond these ranges. A sampling of 10 megacities illustrates a range of characteristic particle composition, dependent on local and regional sources. Long-range transport of pollution

  6. [Influence of nanosize particles of cobalt ferrite on contractile responses of smooth muscle segment of airways].

    PubMed

    Kapilevich, L V; Zaĭtseva, T N; Nosarev, A V; D'iakova, E Iu; Petlina, Z R; Ogorodova, L M; Ageev, B G; Magaeva, A A; Itin, V I; Terekhova, O G; Medvedev, M A

    2012-02-01

    Contractile responses of airways segments of porpoises inhaling nanopowder CoFe2O4 were stidued by means of a mechanographic method. Inhalation of the nanosize particles of CoFe2O4 in vivo and in vitro testing the nanomaterial on isolated smooth muscles led to potentiation histaminergic, cholinergic contractile activity in airways of porpoises and to strengthening of adrenergic relaxing answers. Nanosize particles vary amplitude of hyperpotassium reductions in smooth muscle segments of airways similarly to the effect of depolymerizing drug colchicine.

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

    PubMed

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

    2011-07-01

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

  8. Spatial and monthly trends in speciated fine particle concentration in the United States

    NASA Astrophysics Data System (ADS)

    Malm, William C.; Schichtel, Bret A.; Pitchford, Marc L.; Ashbaugh, Lowell L.; Eldred, Robert A.

    2004-02-01

    In the spring of 1985 an interagency consortium of federal land management agencies and the Environmental Protection Agency established the Interagency Monitoring of Protected Visual Environments (IMPROVE) network to assess visibility and aerosol monitoring for the purpose of tracking spatial and temporal trends of visibility and visibility-impairing particles in rural areas. The program was initiated with 20 monitoring sites and was expanded to 165 sites between 2000 and 2003. This paper reports on fine aerosol data collected in the year 2001 at 143 sites. The major fine (dp < 2.5 μm) particle aerosol species, sulfates, nitrates, organics, light-absorbing carbon, and wind-blown dust, and coarse gravimetric mass are monitored, and at some sites, light scattering and/or extinction are measured. Sulfates, carbon, and crustal material are responsible for most of the fine mass at the majority of locations throughout the United States, while at sites in southern California and the midwestern United States, nitrates can contribute significantly. In the eastern United States, sulfates contribute between 50 and 60% of the fine mass. Sulfate concentrations tend to be highest in the summer months while organic concentrations can be high in the spring, summer, or fall seasons, depending upon fire-related emissions. However, at the two urban sites, Phoenix, Arizona, and Puget Sound, Washington, organics peak during the winter months. Nitrate concentrations also tend to be highest during the winter months. During the spring months in many areas of the western United States, fine soil can contribute as much as 40% of fine mass. The temporal changes in soil concentration that occur simultaneously over much of the western United States including the Rocky Mountain region suggest a large source region, possibly long-range transport of Asian dust.

  9. Characterization of interparticle forces in the packing of cohesive fine particles.

    PubMed

    Yang, R Y; Zou, R P; Yu, A B; Choi, S K

    2008-09-01

    We numerically investigate force structures in the packing of fine cohesive particles using the discrete element method. By changing the particle size and therefore the van der Waals force, the effect of cohesion on the normal contact force and the total normal force, which is the sum of the normal contact forces and the van der Waals forces, is analyzed. It is shown that, with decreasing particle size, the normal contact forces become more uniform and have a narrower and more symmetric distribution, while the distributions of the total normal forces widen. Spatial correlation between the interparticle forces exists for the packing of coarse noncohesive particles. As the particle size decreases, this correlation becomes weaker for the contact forces but stronger for the total normal forces. A comparison between the effective weight of particles and the internal force structure suggests that there are differences between the particle-particle and particle-wall forces. The bimodal distribution of the effective weight indicates that there may exist two phases in the packings when cohesion is present, governed by the compressive and tensile stresses.

  10. Metallic Nickel Nanoparticles May Exhibit Higher Carcinogenic Potential than Fine Particles in JB6 Cells

    PubMed Central

    Bowman, Linda; Zou, Baobo; Mao, Guochuan; Xu, Jin; Castranova, Vincent; Zhao, Jinshun; Ding, Min

    2014-01-01

    While numerous studies have described the pathogenic and carcinogenic effects of nickel compounds, little has been done on the biological effects of metallic nickel. Moreover, the carcinogenetic potential of metallic nickel nanoparticles is unknown. Activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) have been shown to play pivotal roles in tumor initiation, promotion, and progression. Mutation of the p53 tumor suppressor gene is considered to be one of the steps leading to the neoplastic state. The present study examines effects of metallic nickel fine and nanoparticles on tumor promoter or suppressor gene expressions as well as on cell transformation in JB6 cells. Our results demonstrate that metallic nickel nanoparticles caused higher activation of AP-1 and NF-κB, and a greater decrease of p53 transcription activity than fine particles. Western blot indicates that metallic nickel nanoparticles induced a higher level of protein expressions for R-Ras, c-myc, C-Jun, p65, and p50 in a time-dependent manner. In addition, both metallic nickel nano- and fine particles increased anchorage-independent colony formation in JB6 P+ cells in the soft agar assay. These results imply that metallic nickel fine and nanoparticles are both carcinogenetic in vitro in JB6 cells. Moreover, metallic nickel nanoparticles may exhibit higher carcinogenic potential, which suggests that precautionary measures should be taken in the use of nickel nanoparticles or its compounds in nanomedicine. PMID:24691273

  11. Settling velocities of fine suspended particles in the Changjiang Estuary, China

    USGS Publications Warehouse

    Shi, Z.; Zhou, H.J.; Eittreim, S.L.; Winterwerp, J.C.

    2003-01-01

    Point-sampled suspended sediment concentration profiles (grain size largely < 32 ??m) were measured in August 1978, April 1990, and May 1990 in the Changjiang Estuary. They were selectively fit with the Rouse equation in order to calculate the median settling velocities ws,50 of fine suspended particles in the Changjiang Estuary, East China Sea. Calculated settling velocities ranged from 0.4 to 4.1 mm s-1. Furthermore, ws values increased with the mean concentration C?? of sediment in suspension. The best-fit equation for the field settling velocity of fine particles in the Changjiang Estuary can be expressed by the power law: ws = 2.37 C??0.84 (r2 < 0.3). ?? 2003 Elsevier Ltd. All rights reserved.

  12. Morphology of Proeutectoid Ferrite

    NASA Astrophysics Data System (ADS)

    Yin, Jiaqing; Hillert, Mats; Borgenstam, Annika

    2017-01-01

    The morphology of grain boundary nucleated ferrite particles in iron alloys with 0.3 mass pct carbon has been classified according to the presence of facets. Several kinds of particles extend into both grains of austenite and have facets to both. It is proposed that they all belong to a continuous series of shapes. Ferrite plates can nucleate directly on the grain boundary but can also develop from edges on many kinds of particles. Feathery structures of parallel plates on both sides of a grain boundary can thus form. In sections, parallel to their main growth direction, plates have been seen to extend the whole way from the nucleation site at the grain boundary and to the growth front. This happens in the whole temperature range studied from 973 K to 673 K (700 °C to 400 °C). The plates thus grow continuously and not by subunits stopping at limited length and continuing the growth by new ones nucleating. Sometimes, the plates have ridges and in oblique sections they could be mistaken for the start of new plates. No morphological signs were observed indicating a transition between Widmanstätten ferrite and bainitic ferrite. It is proposed that there is only one kind of acicular ferrite.

  13. Morphology of Proeutectoid Ferrite

    NASA Astrophysics Data System (ADS)

    Yin, Jiaqing; Hillert, Mats; Borgenstam, Annika

    2017-03-01

    The morphology of grain boundary nucleated ferrite particles in iron alloys with 0.3 mass pct carbon has been classified according to the presence of facets. Several kinds of particles extend into both grains of austenite and have facets to both. It is proposed that they all belong to a continuous series of shapes. Ferrite plates can nucleate directly on the grain boundary but can also develop from edges on many kinds of particles. Feathery structures of parallel plates on both sides of a grain boundary can thus form. In sections, parallel to their main growth direction, plates have been seen to extend the whole way from the nucleation site at the grain boundary and to the growth front. This happens in the whole temperature range studied from 973 K to 673 K (700 °C to 400 °C). The plates thus grow continuously and not by subunits stopping at limited length and continuing the growth by new ones nucleating. Sometimes, the plates have ridges and in oblique sections they could be mistaken for the start of new plates. No morphological signs were observed indicating a transition between Widmanstätten ferrite and bainitic ferrite. It is proposed that there is only one kind of acicular ferrite.

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

    PubMed Central

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

    2016-01-01

    ABSTRACT OBJECTIVE To analyze the association between fine particulate matter concentration in the atmosphere and hospital care by acute respiratory diseases in children. METHODS Ecological study, carried out in the region of Grande Vitória, Espírito Santo, in the winter (June 21 to September 21, 2013) and summer (December 21, 2013 to March 19, 2014). We assessed data of daily count for outpatient care and hospitalization by respiratory diseases (ICD-10) in children from zero to 12 years in three hospitals in the Region of Grande Vitória. For collecting fine particulate matter, we used portable samplers of particles installed in six locations in the studied region. The Generalized Additive Model with Poisson distribution, fitted for the effects of predictor covariates, was used to evaluate the relationship between respiratory outcomes and concentration of fine particulate matter. RESULTS The increase of 4.2 µg/m3 (interquartile range) in the concentration of fine particulate matter increased in 3.8% and 5.6% the risk of medical care or hospitalization, respectively, on the same day and with six-day lag from the exposure. CONCLUSIONS We identified positive association between outpatient care and hospitalizations of children under 12 years due to acute respiratory diseases and the concentration of fine particulate matter in the atmosphere. PMID:28099552

  15. Measurements of fine particle size using image processing of a laser diffraction image

    NASA Astrophysics Data System (ADS)

    Tsubaki, Kotaro

    2016-08-01

    The measurement of fine particle size is important in spray systems, minimum quantity lubrication, and weather observation. Introducing the recent progress of imaging techniques, the authors developed a portable measurement system. To overcome the large light intensity difference between the incident laser light and diffracted light and the limitation of the dynamic range of imaging devices, the event correlation was adopted. The growth of droplets in fog was experimentally measured.

  16. Biomagnetic of Apatite-Coated Cobalt Ferrite: A Core-Shell Particle for Protein Adsorption and pH-Controlled Release.

    PubMed

    Tang, I-Ming; Krishnamra, Nateetip; Charoenphandhu, Narattaphol; Hoonsawat, Rassmidara; Pon-On, Weeraphat

    2011-12-01

    Magnetic nanoparticle composite with a cobalt ferrite (CoFe2O4, (CF)) core and an apatite (Ap) coating was synthesized using a biomineralization process in which a modified simulated body fluid (1.5SBF) solution is the source of the calcium phosphate for the apatite formation. The core-shell structure formed after the citric acid-stabilized cobalt ferrite (CFCA) particles were incubated in the 1.5 SBF solution for 1 week. The mean particle size of CFCA-Ap is about 750 nm. A saturation magnetization of 15.56 emug(-1) and a coercivity of 1808.5 Oe were observed for the CFCA-Ap obtained. Bovine serum albumin (BSA) was used as the model protein to study the adsorption and release of the proteins by the CFCA-Ap particles. The protein adsorption by the CFCA-Ap particles followed a more typical Freundlich than Langmuir adsorption isotherm. The BSA release as a function of time became less rapid as the CFCA-Ap particles were immersed in higher pH solution, thus indicating that the BSA release is dependent on the local pH.

  17. Biomagnetic of Apatite-Coated Cobalt Ferrite: A Core–Shell Particle for Protein Adsorption and pH-Controlled Release

    PubMed Central

    2011-01-01

    Magnetic nanoparticle composite with a cobalt ferrite (CoFe2O4, (CF)) core and an apatite (Ap) coating was synthesized using a biomineralization process in which a modified simulated body fluid (1.5SBF) solution is the source of the calcium phosphate for the apatite formation. The core–shell structure formed after the citric acid–stabilized cobalt ferrite (CFCA) particles were incubated in the 1.5 SBF solution for 1 week. The mean particle size of CFCA-Ap is about 750 nm. A saturation magnetization of 15.56 emug-1 and a coercivity of 1808.5 Oe were observed for the CFCA-Ap obtained. Bovine serum albumin (BSA) was used as the model protein to study the adsorption and release of the proteins by the CFCA-Ap particles. The protein adsorption by the CFCA-Ap particles followed a more typical Freundlich than Langmuir adsorption isotherm. The BSA release as a function of time became less rapid as the CFCA-Ap particles were immersed in higher pH solution, thus indicating that the BSA release is dependent on the local pH. PMID:27502643

  18. Fine particles on Mars - Observations with the Viking 1 lander cameras

    NASA Technical Reports Server (NTRS)

    Mutch, T. A.; Arvidson, R. E.; Binder, A. B.; Huck, F. O.; Levinthal, E. C.; Liebes, S., Jr.; Morris, E. C.; Nummedal, D.; Pollack, J. B.; Sagan, C.

    1976-01-01

    Drifts of fine-grained sediment are present in the vicinity of the Viking 1 lander. Many drifts occur in the lees of large boulders. Morphologic analysis indicates that the last dynamic event was one of general deflation for at least some drifts. Particle cohesion implies that there is a distinct small-particle upturn in the threshold velocity-particle size curve; the apparent absence of the most easily moved particles (150 micrometers in diameter) may be due to their preferential transport to other regions or their preferential collisional destruction. A twilight rescan with lander cameras indicates a substantial amount of red dust with mean radius on the order of 1 micrometer in the atmosphere.

  19. Fine particles on mars: Observations with the viking 1 lander cameras

    USGS Publications Warehouse

    Mutch, T.A.; Arvidson, R. E.; Binder, A.B.; Huck, F.O.; Levinthal, E.C.; Liebes, S.; Morris, E.C.; Nummedal, D.; Pollack, James B.; Sagan, C.

    1976-01-01

    Drifts of fine-grained sediment are present in the vicinity of the Viking 1 lander. Many drifts occur in the lees of large boulders. Morphologic analysis indicates that the last dynamic event was one of general deflation for at least some drifts. Particle cohesion implies that there is a distinct small-particle upturn in the threshold velocity-particle size curve; the apparent absence of the most easily moved particles (150 micrometers in diameter) may be due to their preferential transport to other regions or their preferential collisional destruction. A twilight rescan with lander cameras indicates a substantial amount of red dust with mean radius on the order of 1 micrometer in the atmosphere.

  20. Movement of fine particles on an air bubble surface studied using high-speed video microscopy.

    PubMed

    Nguyen, Anh V; Evans, Geoffrey M

    2004-05-01

    A CCD high-speed video microscopy system operating at 1000 frames per second was used to obtain direct quantitative measurements of the trajectories of fine glass spheres on the surface of air bubbles. The glass spheres were rendered hydrophobic by a methylation process. Rupture of the intervening water film between a hydrophobic particle and an air bubble with the consequent formation of a three-phase contact was observed. The bubble-particle sliding attachment interaction is not satisfactorily described by the available theories. Surface forces had little effect on the particle sliding with a water film, which ruptured probably due to the submicrometer-sized gas bubbles existing at the hydrophobic particle-water interface.

  1. Fine particles on Mars: observations with the viking 1 lander cameras.

    PubMed

    Mutch, T A; Arvidson, R E; Binder, A B; Huck, F O; Levinthal, E C; Liebes, S; Morris, E C; Nummedal, D; Pollack, J B; Sagan, C

    1976-10-01

    Drifts of fine-grained sediment are present in the vicinity of the Viking 1 lander. Many drifts occur in the lees of large boulders. Morphologic analysis indicates that the last dynamic event was one of general deflation for at least some drifts. Particle cohesion implies that there is a distinct small-particle upturn in the threshold velocity-particle size curve; the apparent absence of the most easily moved particles (150 micrometers in diameter) may be due to their preferential transport to other regions or their preferential collisional destruction. A twilight rescan with lander cameras indicates a substantial amount of red dust with mean radius on the order of 1 micrometer in the atmosphere.

  2. Fine structure of all-particle energy spectrum in the knee region

    NASA Astrophysics Data System (ADS)

    Garyaka, A.; Martirosov, R.; Ter-Antonyan, S.; Babayan, H.; Erlykin, A.; Gallant, Y.; Jones, L.; Kempa, J.; Nikolskaya, N.; Pattison, B.; Procureur, J.; Sokhoyan, S.; Vardanyan, H.

    2013-02-01

    All-particle energy spectrum in the knee region obtained from extensive air shower (EAS) measurements (GAMMA experiment, 700 g/cm2, Armenia) is presented. Energies of primary particles in the range of 106-108 GeV were evaluated on the basis of observed shower parameters Nch,Nμ, s, θ and corresponding parameterisation of CORSIKA simulated database for SIBYLL interaction model. All shower detection and reconstruction uncertainties were included in the simulated showers for four kinds (H, He, O, Fe) of primary nuclei. The reliability of observed all-particle energy spectrum is investigated from viewpoint of methodical errors and statistical fluctuations. Observed fine structure of all-particle energy spectrum can be interpreted by the rigidity-dependent steepening Galactic diffuse nuclei flux and an additional iron component in the region of 70-80 PeV primary energies most likely originated from nearby pulsars.

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

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Rowson, Neil; Ingram, Andy

    2016-11-01

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

  4. Effect of race on fine particle deposition for oral and nasal breathing.

    PubMed

    Bennett, William D; Zeman, Kirby L

    2005-11-01

    Nasal efficiency for removing fine particles from inhaled air may be affected by variations in nasal structure associated with race. In 11 African American and 11 Caucasian adults (age 18-31 yr) we measured the fractional deposition (DF) of fine particles (1 and 2 mum mass median aerodynamic diameter) (MMAD) for oral and nasal breathing using individual breathing patterns previously measured by respiratory inductance plethysmography during a graded exercise protocol. DF for both nasal and mouth breathing was measured separately by laser photometry at the same tidal volume and breathing rate for resting and light exercise (20% of maximum work load) conditions. From these DF measures, nasal deposition efficiency (NDE) was calculated for each condition. For light exercise conditions, NDE for both 1- and 2-microm particles was less in African Americans versus Caucasians, 0.15 +/- 0.07 (SD) versus 0.24 +/- 0.11 for 1-microm particles (p = .03), and 0.29 +/- 0.13 versus 0.44 +/- 0.11 for 2-microm particles (p = .006). The racial differences in NDE were associated with racial differences in nasal resistance and nostril shape. These race-dependent nasal efficiencies are dosimetric factors that should be considered in modeling and assessing particulate dose from human exposure to air pollutants.

  5. Application of acoustic agglomeration to reduce fine particle emissions from coal combustion plants

    SciTech Connect

    Gallego-Juarez, J.A.; Riera-Franco De Sarabia, E.; Rodriguez-Corral, G.

    1999-11-01

    Removal of fine particles (smaller than 2.5 {micro}m) from industrial flue gases is, at present, one of the most important problems in air pollution abatement. These particles which are hazardous because of their ability to penetrate deeply into the lungs, are difficult to remove by conventional separation technology. Sonic energy offers a means to solve this problem. The application of a high-intensity acoustic field to an aerosol induces agglomeration processes which changes the size distribution in favor of larger particles, which are then easier to precipitate with a conventional separator. In this work, the authors present a semiindustrial pilot plant in which this process is applied for reduction of particle emissions in coal combustion fumes. This installation basically consists of an acoustic agglomeration chamber with a rectangular cross-section, driven by four high-power and highly directional acoustic transducers of 10 and/or 20 kHz, and an electrostatic precipitator (ESP). In the experiments, a fluidized bed coal combustor was used as fume generator, and a sophisticated air sampling station was set up to carry out measurements with fume flow rates up to about 2,000 m{sup 3}/h, gas temperatures of about 150 C, and mass concentrations in the range 1--5 g/m{sup 3}. The fine particle reduction produced by the acoustic filter was about 40% of the number concentration.

  6. Contribution of fine particle sulfates to light scattering in St. Louis summer aerosol

    SciTech Connect

    Vossler, T.L.; Macias, E.S.

    1986-12-01

    The contribution of fine particle (NH/sub 4/)/sub 2/SO/sub 4/ to total light scattering was calculated from measured sulfur size distributions and estimates of water that might be associated with this deliquescent species. The most common type of sulfur size distribution observed had a major sulfur mass peak between 0.5 and 1.0 ..mu..m in diameter and was associated with the highest levels of b/sub scat/. A less common type with no peak above 0.5 ..mu..m was associated only with low values of b/sub scat/. On average, (NH/sub 4/)SO/sub 4/ plus associated water contributed 68% of the total light scattering due to particles during the summer of 1984. The measured light scattering coefficient, b/sub scat/, and (NH/sub 4/)/sub 2/SO/sub 4/ plus associated water were extremely well correlated. b/sub scat/ and total fine particle mass were not as well correlated, because the correlation between b/sub scat/ and non-sulfate fine mass was poor. The average calculated light scattering efficiency of (NH/sub 4/)/sub 2/SO/sub 4/ plus water was 4.2 m/sup 2//g. The higher values were associated with sulfur size distributions with a major peak above 0.5 ..mu..m.

  7. Superparamagnetic Particle Size Limit of Mn-Zn Ferrite Nanoparticles Synthesised Through Aqueous Method

    NASA Astrophysics Data System (ADS)

    Joseyphus, R. Justin; Narayanasamy, A.; Jeyadevan, B.; Shinoda, K.; Tohji, K.

    2006-05-01

    Mn0.67Zn0.33Fe2O4 nanoparticles with size ranging from 20 to 80 nm have been synthesized using the modified oxidation method. The Curie temperatures for all the samples are found to be within 630 ± 5 K suggesting that there is no size-dependent cation distribution. Mössbauer studies on the synthesized nanoparticles suggest that the critical particle size limit for superparamagnetism to be about 25 nm at 293 K.

  8. Superparamagnetic Particle Size Limit of Mn-Zn Ferrite Nanoparticles Synthesised Through Aqueous Method

    SciTech Connect

    Joseyphus, R. Justin; Narayanasamy, A.; Jeyadevan, B.; Shinoda, K.; Tohji, K.

    2006-05-15

    Mn0.67Zn0.33Fe2O4 nanoparticles with size ranging from 20 to 80 nm have been synthesized using the modified oxidation method. The Curie temperatures for all the samples are found to be within 630 {+-} 5 K suggesting that there is no size-dependent cation distribution. Moessbauer studies on the synthesized nanoparticles suggest that the critical particle size limit for superparamagnetism to be about 25 nm at 293 K.

  9. Magnetic Soret effect in a hydrocarbon based colloid containing surfacted Mn-Zn ferrite particles

    NASA Astrophysics Data System (ADS)

    Blums, E.; Odenbach, S.; Mezulis, A.; Maiorov, M.

    1999-07-01

    The Soret effect has been investigated in a hydrocarbon based magnetic fluid containing surfacted Mn 0.5Zn 0.5Fe 2O 4 nanoparticles with a magnetic volume concentration of 2.3%. The magnetic fluid fills up a vertical diffusion column which consists of a flat vertical channel between two walls and two reservoirs at the ends of the channel. One wall of the channel is being heated while the another one is cooled, maintaining a temperature gradient over the channel's width that leads to separation of particles due to the Soret effect as well as the convective flow in the channel. The combination of the two mentioned effects brings up a measurable change of the concentration of magnetic particles in both reservoirs. The results have been obtained for uniform magnetic fields, aligned parallelly and normally to the temperature gradient respectively, by measuring the concentration of magnetic particles in the reservoirs. Obtained results are in good qualitative agreement with thermodiffusion column theory, published earlier (E. Blums, J. Magn. Magn. Mater. 149 (1995) 111).

  10. Analysis of Pneumatic Fine Particle Peening Process by Using a High-Speed

    NASA Astrophysics Data System (ADS)

    Ito, Tatsuya; Kikuchi, Shoichi; Hirota, Yo; Sasago, Atsushi; Komotori, Jun

    In this study, the peening behavior of shot particles in a fine particle peening (FPP) process such as velocity and impact angles were analyzed by using a high-speed-camera. Results showed that the velocity of shot particles depended on a peening pressure; the higher the peening pressure, the higher the particle velocity. The particle velocity measured in this study was approximately 120 m/s; this was much higher than that of the conventional shot peening (SP) process. This was because the air resistance of shot particles in the FPP process was higher than that of shot particles in the SP process. In order to discuss the surface modification effect of the FPP process, commercial-grade pure iron treated by the FPP process was characterized by micro-Vickers hardness tester and scanning electron microscope (SEM). Thickness of hardened layer treated with higher peening pressure was much higher than that of the lower pressure treated one. The unique microstructure with stratification patterns, which was harder than that of the other part, was observed near the specimen surface. The reason for the microstructural changes by the FPP treatment was discussed based on the kinetic energy of shot particles.

  11. The exposure to coarse, fine and ultrafine particle emissions from concrete mixing, drilling and cutting activities.

    PubMed

    Azarmi, Farhad; Kumar, Prashant; Mulheron, Mike

    2014-08-30

    Building activities generate coarse (PM10≤10μm), fine (PM2.5≤2.5μm) and ultrafine particles (<100nm) making it necessary to understand both the exposure levels of operatives on site and the dispersion of ultrafine particles into the surrounding environment. This study investigates the release of particulate matter, including ultrafine particles, during the mixing of fresh concrete (incorporating Portland cement with Ground Granulated Blastfurnace Slag, GGBS or Pulverised Fuel Ash, PFA) and the subsequent drilling and cutting of hardened concrete. Particles were measured in the 5-10,000nm size range using a GRIMM particle spectrometer and a fast response differential mobility spectrometer (DMS50). The mass concentrations of PM2.5-10 fraction contributed ∼52-64% of total mass released. The ultrafine particles dominated the total particle number concentrations (PNCs); being 74, 82, 95 and 97% for mixing with GGBS, mixing with PFA, drilling and cutting, respectively. Peak values measured during the drilling and cutting activities were 4 and 14 times the background. Equivalent emission factors were calculated and the total respiratory deposition dose rates for PNCs for drilling and cutting were 32.97±9.41×10(8)min(-1) and 88.25±58.82×10(8)min(-1). These are a step towards establishing number and mass emission inventories for particle exposure during construction activities. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    PubMed

    Zhao, H; Stephens, B

    2017-01-01

    Much of human exposure to particulate matter of outdoor origin occurs inside buildings, particularly in residences. The particle penetration factor through leaks in a building's exterior enclosure assembly is a key parameter that governs the infiltration of outdoor particles. However, experimental data for size-resolved particle penetration factors in real buildings, as well as penetration factors for fine particles less than 2.5 μm (PM2.5 ) and ultrafine particles less than 100 nm (UFPs), remain limited, in part because of previous limitations in instrumentation and experimental methods. Here, we report on the development and application of a modified test method that utilizes portable particle sizing instrumentation to measure size-resolved infiltration factors and envelope penetration factors for 0.01-2.5 μm particles, which are then used to estimate penetration factors for integral measures of UFPs and PM2.5 . Eleven replicate measurements were made in an unoccupied apartment unit in Chicago, IL to evaluate the accuracy and repeatability of the test procedure and solution methods. Mean estimates of size-resolved penetration factors ranged from 0.41 ± 0.14 to 0.73 ± 0.05 across the range of measured particle sizes, while mean estimates of penetration factors for integral measures of UFPs and PM2.5 were 0.67 ± 0.05 and 0.73 ± 0.05, respectively. Average relative uncertainties for all particle sizes/classes were less than 20%. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

    NASA Astrophysics Data System (ADS)

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

    1996-08-01

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

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

    SciTech Connect

    Serrano, P.; Allen, G.; Castillejos, M.; Gold, D.; Speizer, F.; Hernandez, M.; Hayes, C.; McDonnell, W.

    1994-12-31

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  17. Synthesis of Mn1-xZnxFe2O4 ferrite powder by co-precipitation method

    NASA Astrophysics Data System (ADS)

    Irfan, Salma; Ajaz-un-Nabi, M.; Jamil, Yasir; Amin, Nasir

    2014-06-01

    Ferrimagnetic substances referred to as ferrites are ionic crystals whose chemical composition is of the form XFe2 O4 where X signifies a divalent metal. Magnetic Nano sized ferrites have found a significant potential in many applications, such as magnetic recording media, Ferro fluids and radar absorbing coating. Ferrites are widely used in many industrial applications due to their spontaneous magnetization. Soft ferrites of Mn-Zn, Ni-Zn and Mg-Mn are well known for their high magnetic permeability. In the present research work we have prepared fine Mn1-xZnxFe2O4 ferrite powder with varying x concentrations (0.25-0.75) by metal chloride precursors through a co-precipitation technique by pipette drop method using aqueous NaOH solution for comparing their spontaneous magnetization and particle size. The co-precipitation technique is a high way to produce chemically homogeneous powder with fine particle size in nanometers (22.5nm-74.5nm).The effect of x-concentration on the particle size of the Mn(1-x) Zn(x) ferrite has been discussed on the basis of XRD. The crystalline phases have been identified by X-ray diffraction with Cu-Kα radiations. The XRD patterns have verified that the specimen has spinal type structure. The observable peaks are broad since the size of the particles is small. We have concluded that at constants temperature particle size increases with increasing x-concentrations. Effect of different concentrations of x (Zn+2) on the spontaneous magnetization of different Mn(1-x) Zn(x) Fe2O4 sample is determined. We have reached the conclusion that all the samples of Mn(1-x) Zn(x) Fe2 O4 ferrites were magnetic either of low or high magnetization. The maximum spontaneous magnetization and minimum particle size is obtained at x=0.25 (at digestion temperature=65°C).

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

    NASA Astrophysics Data System (ADS)

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

    2004-09-01

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

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

    PubMed Central

    2011-01-01

    Inhalation of (nano)particles may lead to pulmonary inflammation. However, the precise mechanisms of particle uptake and generation of inflammatory mediators by alveolar macrophages (AM) are still poorly understood. The aim of this study was to investigate the interactions between particles and AM and their associated pro-inflammatory effects in relation to particle size and physico-chemical properties. NR8383 rat lung AM were treated with ultrafine (uf), fine (f) TiO2 or fine crystalline silica (DQ12 quartz). Physico-chemical particle properties were investigated by transmission electron microscopy, elemental analysis and thermogravimetry. Aggregation and agglomeration tendency of the particles were determined in assay-specific suspensions by means of dynamic light scattering. All three particle types were rapidly taken up by AM. DQ12 and ufTiO2 , but not fTiO2 , caused increased extracellular reactive oxygen species (ROS), heme oxygenase 1 (HO-1) mRNA expression and tumor necrosis factor (TNF)-α release. Inducible nitric oxide synthase (iNOS) mRNA expression was increased most strongly by ufTiO2 , while DQ12 exclusively triggered interleukin (IL) 1β release. However, oscillations of intracellular calcium concentration and increased intracellular ROS were observed with all three samples. Uptake inhibition experiments with cytochalasin D, chlorpromazine and a Fcγ receptor II (FcγRII) antibody revealed that the endocytosis of fTiO2 by the macrophages involves actin-dependent phagocytosis and macropinocytosis as well as clathrin-coated pit formation, whereas the uptake of ufTiO2 was dominated by FcγIIR. The uptake of DQ12 was found to be significantly reduced by all three inhibitors. Our findings suggest that the contrasting AM responses to fTiO2 , ufTiO2 and DQ12 relate to differences in the involvement of specific uptake mechanisms. PMID:21995556

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

    PubMed

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

    2010-04-01

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

  1. Mortality and ambient fine particles in southwest Mexico City, 1993-1995.

    PubMed Central

    Borja-Aburto, V H; Castillejos, M; Gold, D R; Bierzwinski, S; Loomis, D

    1998-01-01

    ++Epidemiologic studies have focused attention on the health effects of fine particulate air pollutants <2.5 microm in diameter (PM2.5). To further characterize the potential effects of fine particles, we investigated the relationship of air pollution to mortality in Mexico City during 1993-1995. The concentration of PM2.5 was measured on a 24-hr integrated basis; concentrations of NO2 and ozone were measured hourly and reduced to 24-hr means. Daily mortality was determined from death registration records, and Poisson regression was used to model daily death counts as a function of air pollutant levels on the same and previous days, while controlling for temperature and periodic cycles. Without taking other air pollutants into account, a 10 microg/m3 increase in the level of PM2.5 was associated with a 1.4% increase in total mortality, both on the current day and 4 days after exposure [95% confidence interval (CI), 0.2-2.5]. An equivalent increase in PM2.5 was also associated with somewhat larger excesses of deaths among people over 65 years of age and from cardiovascular and respiratory causes, which occurred after a lag of 4 days. The mean concentration of ozone over a 2-day period was associated with a 1.8% increase in mortality from cardiovascular diseases. NO2 was not consistently related to mortality. Fine particles had an independent effect on mortality when modeled simultaneously with other pollutants, and the association of ozone with cardiovascular mortality was strengthened after adjusting for NO2 and PM2.5. These results support previous findings that urban air pollution at current levels leads to excess mortality and suggest that fine particles may play a causal role in producing that excess. Images Figure 1 PMID:9831546

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

    NASA Astrophysics Data System (ADS)

    Azarmi, Farhad; Kumar, Prashant; Mulheron, Mike; Colaux, Julien L.; Jeynes, Chris; Adhami, Siavash; Watts, John F.

    2015-08-01

    Understanding of the emissions of coarse (PM10 ≤10 μm), fine (PM2.5 ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5-10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    Assessing the environmental, health, and climate impacts of bioaerosols requires knowledge of their size and abundance. These two properties were assessed through daily measurements of chemical tracers for pollens (sucrose, fructose, and glucose), fungal spores (mannitol and glucans), and Gram-negative bacterial endotoxins in two particulate matter (PM) size modes: fine particles (< 2.5 µm) and coarse particles (2.5-10 µm) as determined by their aerodynamic diameter. Measurements were made during the spring tree pollen season (mid-April to early May) and late summer ragweed season (late August to early September) in the Midwestern US in 2013. Under dry conditions, pollen, and fungal spore tracers were primarily in coarse PM (> 75 %), as expected for particles greater than 2.5 µm. Rainfall on 2 May corresponded to maximum atmospheric pollen tracer levels and a redistribution of pollen tracers to the fine PM fraction (> 80 %). Both changes were attributed to the osmotic rupture of pollen grains that led to the suspension of fine-sized pollen fragments. Fungal spore tracers peaked in concentration following spring rain events and decreased in particle size, but to a lesser extent than pollens. A short, heavy thunderstorm in late summer corresponded to an increase in endotoxin and glucose levels, with a simultaneous shift to smaller particle sizes. Simultaneous increase in bioaerosol levels and decrease in their size have significant implications for population exposures to bioaerosols, particularly during rain events. Chemical mass balance (CMB) source apportionment modeling and regionally specific pollen profiles were used to apportion PM mass to pollens and fungal spores. Springtime pollen contributions to the mass of particles < 10 µm (PM10) ranged from 0.04 to 0.8 µg m-3 (0.2-38 %, averaging 4 %), with maxima occurring on rainy days. Fungal spore contributions to PM10 mass ranged from 0.1 to 1.5 µg m-3 (0.8-17 %, averaging 5 %), with maxima occurring after

  4. Synthesis of Ferrite Nickel Nano-particles and Its Role as a p-Dopant in the Improvement of Hole Injection of an Organic Light-Emitting Diode

    NASA Astrophysics Data System (ADS)

    Noori, Maryam; Jafari, Mohammad Reza; Hosseini, Sayed Mohsen; Shahedi, Zahra

    2017-07-01

    We fabricated an organometallic complex based on zinc ions using zinc complex as a fluorescent in organic light-emitting diodes (OLEDs). Also, the nano-particles of ferrite nickel were produced in a simple aqueous system prepared by mixing Ni (NO3)2, Fe (NO3)3 and deionized water solutions. The synthesized zinc bis (8-hydroxyquinoline) (Znq2) complex and NiFe2O4 nano-particles were characterized by using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) as well as photoluminescence spectroscopy analysis. Their energy level was also determined by some cyclic voltammetry (CV) measurements. The maximum green photoluminescence was observed at 565 nm. The nano-particles of ferrite nickel were utilized in preparation of OLEDs by blending of the magnetic nano-particles with PEDOT:PSS and Zn-complex solutions. The electrical and optical performance of prepared OLEDs with/without doped nano-particle was studied. The samples were configured into two structures: (1) Indium Tin Oxide (ITO)/ poly(3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/Znq2/(2-4-biphenylyl)-5-phenyl-oxadiazole (PBD)/aluminum (Al) and (2) ITO/PEDOT:PSS:NiFe2O4(NPs)/Znq2/PBD/Al. Obtained results showed that the current density and electroluminescence efficiency were increased and the turn-on voltage decreased (about 3 V) by using nano-particles into a PEDOT:PSS layer (Hole transport layer). Also, the electroluminescence efficiency was decreased by incorporating magnetic nano-particles into a Zn-complex layer (emissive layer). It was found that utilizing NiFe2O4 nano-particles caused an increase of hole-injection layer conductivity effectively and a decrease of the turn-on voltage.

  5. Synthesis of Ferrite Nickel Nano-particles and Its Role as a p-Dopant in the Improvement of Hole Injection of an Organic Light-Emitting Diode

    NASA Astrophysics Data System (ADS)

    Noori, Maryam; Jafari, Mohammad Reza; Hosseini, Sayed Mohsen; Shahedi, Zahra

    2017-02-01

    We fabricated an organometallic complex based on zinc ions using zinc complex as a fluorescent in organic light-emitting diodes (OLEDs). Also, the nano-particles of ferrite nickel were produced in a simple aqueous system prepared by mixing Ni (NO3)2, Fe (NO3)3 and deionized water solutions. The synthesized zinc bis (8-hydroxyquinoline) (Znq2) complex and NiFe2O4 nano-particles were characterized by using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) as well as photoluminescence spectroscopy analysis. Their energy level was also determined by some cyclic voltammetry (CV) measurements. The maximum green photoluminescence was observed at 565 nm. The nano-particles of ferrite nickel were utilized in preparation of OLEDs by blending of the magnetic nano-particles with PEDOT:PSS and Zn-complex solutions. The electrical and optical performance of prepared OLEDs with/without doped nano-particle was studied. The samples were configured into two structures: (1) Indium Tin Oxide (ITO)/ poly(3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/Znq2/(2-4-biphenylyl)-5-phenyl-oxadiazole (PBD)/aluminum (Al) and (2) ITO/PEDOT:PSS:NiFe2O4(NPs)/Znq2/PBD/Al. Obtained results showed that the current density and electroluminescence efficiency were increased and the turn-on voltage decreased (about 3 V) by using nano-particles into a PEDOT:PSS layer (Hole transport layer). Also, the electroluminescence efficiency was decreased by incorporating magnetic nano-particles into a Zn-complex layer (emissive layer). It was found that utilizing NiFe2O4 nano-particles caused an increase of hole-injection layer conductivity effectively and a decrease of the turn-on voltage.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    PubMed

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

    2011-09-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    Mineral dust interacts with incoming/outgoing radiation, gases, other aerosols, and clouds. The assessment of its optical and chemical impacts requires knowledge of the physical and chemical properties of bulk dust and single particles. Despite the existence of a large body of data from field measurements and laboratory analyses, the internal properties of single dust particles have not been defined precisely. Here, we report on the mineralogical organization and internal structures of individual fine ( < 5 µm) Saharan dust particles sampled at Tenerife, Canary Islands. The bulk of Tenerife dust was composed of clay minerals (81 %), followed by quartz (10 %), plagioclase (3 %), and K-feldspar (2 %). Cross-sectional slices of Saharan dust particles prepared by the focused ion beam technique were analyzed by transmission electron microscopy (TEM) to probe the particle interiors. TEM analysis showed that the most common particle type was clay-rich agglomerate, dominated by illite-smectite series clay minerals with subordinate kaolinite. Submicron grains of iron (hydr)oxides (goethite and hematite) were commonly dispersed through the clay-rich particles. The median total volume of the iron (hydr)oxide grains included in the dust particles was estimated to be about 1.5 % vol. The average iron content of clay minerals, assuming 14 wt % H2O, was determined to be 5.0 wt %. Coarse mineral cores, several micrometers in size, were coated with thin layers of clay-rich agglomerate. Overall, the dust particles were roughly ellipsoidal, with an average axial ratio of 1.4 : 1.0 : 0.5. The mineralogical and structural properties of single Saharan dust particles provide a basis for the modeling of dust radiative properties. Major iron-bearing minerals, such as illite-smectite series clay minerals and iron (hydr)oxides, were commonly submicron- to nano-sized, possibly enhancing their biogeochemical availability to remote marine ecosystems lacking micronutrients.

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

    NASA Astrophysics Data System (ADS)

    Amano, Y.; Nanbu, H.; Kameyama, Y.; Komotori, J.

    2010-06-01

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

  10. Reconciling satellite aerosol optical thickness and surface fine 5 particle mass through aerosol liquid water

    SciTech Connect

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

    2016-11-28

    Summertime aerosol optical thickness (AOT) over the Southeast U.S. is sharply enhanced over wintertime values. This seasonal pattern is unique and of particular interest because temperatures there have not warmed over the past 100 years. Patterns in surface fine particle mass are inconsistent with satellite reported AOT. In this work, we attempt to reconcile the spatial and temporal distribution of AOT over the U.S. with particle mass measurements at the surface by examining trends in aerosol liquid water (ALW), a particle constituent that scatters radiation affecting the satellite AOT, but is removed in mass measurements at routine surface monitoring sites. We employ the thermodynamic model ISORROPIAv2.1 to estimate ALW mass concentrations at IMRPOVE sites using measured ion mass concentrations and NARR meteorological data. Our findings suggest ALW provides a plausible explanation for the geographical and seasonal patterns in AOT and can reconcile previously noted discrepancies with surface mass measurements.

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

    PubMed

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

    2011-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhao, Yun; Zeng, Xinwu; Tian, Zhangfu

    2015-10-01

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

  13. Dielectric Behavior of Nano sized Particles of Zn-Cr Ferrite

    NASA Astrophysics Data System (ADS)

    Pareek, S. P.; Prasad, Arun S.; Dolia, S. N.; Kumar, S.; Dhawan, M. S.; Samariya, Arvind; Asokan, K.; Parashar, Jyoti; Saxena, V. K.; Sharma, K. B.

    2011-11-01

    Dielectric behavior of nanosized ZnCrxFe2-xO4 particles with x = 0.2, 0.4, 0.6 and 0.8, synthesized using sol-gel method have been studied. The XRD patterns confirm formation of single phase cubic spinel structure of the specimens. The dielectric behavior of all the samples has been studied at 300 K as a function of frequency in the range 75 kHz to 10 MHz. Both the real value of dielectric constant (ɛ̗) and the dielectric loss factor (tanδ) decreases with frequency respectively for all the samples. This decrease in the values could be explained on the basis of available ferrous, i.e. Fe2+, ions on octahedral sites such that beyond a certain frequency of applied electric field the electronic exchange between the ferrous and ferric ions i.e. Fe2+↔Fe3+ cannot follow the applied alternating electric field. Also, a gradual reduction in both ɛ̗ and tanδ observed as Cr concentration increases.

  14. Additional Final Area Designations and Technical Amendment for the 2012 Annual Fine Particle Standard Established in 2012 - Mar 2015

    EPA Pesticide Factsheets

    EPA is establishing or revising initial area designations and a technical amendment to correct an inadvertent error in the initial designation for one area for the 2012 annual national ambient air quality standards for fine particle pollution.

  15. Interaction of fine particles and nanoparticles with red blood cells visualized with advanced microscopic techniques.

    PubMed

    Rothen-Rutishauser, Barbara M; Schürch, Samuel; Haenni, Beat; Kapp, Nadine; Gehr, Peter

    2006-07-15

    So far, little is known about the interaction of nanoparticles with lung cells, the entering of nanoparticles, and their transport through the blood stream to other organs. The entering and localization of different nanoparticles consisting of differing materials and of different charges were studied in human red blood cells. As these cells do not have any phagocytic receptors on their surface, and no actinmyosin system, we chose them as a model for nonphagocytic cells to study how nanoparticles penetrate cell membranes. We combined different microscopic techniques to visualize fine and nanoparticles in red blood cells: (I) fluorescent particles were analyzed by laser scanning microscopy combined with digital image restoration, (II) gold particles were analyzed by conventional transmission electron microscopy and energy filtering transmission electron microscopy, and (III) titanium dioxide particles were analyzed by energy filtering transmission electron microscopy. By using these differing microscopic techniques we were able to visualize and detect particles < or = 0.2 microm and nanoparticles in red blood cells. We found that the surface charge and the material of the particles did not influence their entering. These results suggest that particles may penetrate the red blood cell membrane by a still unknown mechanism different from phagocytosis and endocytosis.

  16. Fine encapsulation of dual-particle electronic ink by incorporating block copolymer for electrophoretic display application.

    PubMed

    Yin, Pei-Pei; Wu, Gang; Dai, Run-Ying; Qin, Wen-Long; Wang, Mang; Chen, Hong-Zheng

    2012-12-15

    The design of the oppositely charged ink particles based on titanium dioxide and carbon black for the monochrome electrophoretic display (EPD) was reported. The white ink particles with acidic surface and black ink particles with basic surface were synthesized and sterically stabilized by long alkyl chains, which were charged oppositely by mixing with basic surfactant (OLOA 1200) and acidic surfactant (Span 80), respectively. The electrophoretic mobility and the Zeta potential were -3.87×10(-10)m(2)V(-1)s(-1) and -25.1 mV for the white ink particles, 3.79×10(-10)m(2)V(-1)s(-1) and 24.6 mV for the black ink particles. In addition, the block copolymer, poly(lauryl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (PLMA-b-PDMAEMA) synthesized by atom transfer radical polymerization (ATRP), was first incorporated in the modification of the pigments for the fine encapsulation. Then, a stable dual-particle electronic ink with contrast ratio of 120:1 was prepared and encapsulated with the gelatin (GE)/sodium carboxymethylcellulose (NaCMC)/sodium dodecyl sulfate (SDS) microcapsules by complex coacervation method. Finally, the matrix character display prototype driven at a low voltage exhibited excellent performance, the contrast ratio of which was 8:1 at 9 V DC. Copyright © 2012 Elsevier Inc. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    Azarmi, Farhad; Kumar, Prashant

    2016-07-01

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

  18. A study of multistage/multifunction column for fine particle separation

    SciTech Connect

    Chiang, Shiao-Hung

    1996-07-01

    The overall objective of the research program is to explore the potential application of a new invention involving a multistage column equipped with vortex-inducing loop-flow contactors (hereafter referred to as the multistage column) for fine coal cleaning process. The research work will identify the design parameters and their effects on the performance of the separation process. The results of this study will provide an engineering basis for further development of this technology in coal cleaning and in the general areas of fluid/particle separation. In the last quarter, we investigated the fine coal beneficiation behaviors in the multistage column and the conventional column. In this quarter, we have initiated the wastewater treatment tests program to verify the multifunction features of the multistage column. We also performed data analysis of the bubble sizes using a model based on the unified proportionality equation. 7 refs., 10 figs., 7 tabs.

  19. Comparing Inhaled Ultrafine versus Fine Zinc Oxide Particles in Healthy Adults

    PubMed Central

    Beckett, William S.; Chalupa, David F.; Pauly-Brown, Andrea; Speers, Donna M.; Stewart, Judith C.; Frampton, Mark W.; Utell, Mark J.; Huang, Li-Shan; Cox, Christopher; Zareba, Wojciech; Oberdörster, Günter

    2005-01-01

    Rationale: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 μm diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1–1.0 μm diameter). Objectives: We compared exposure–response relationships for respiratory, hematologic, and cardiovascular endpoints between ultrafine and accumulation mode zinc oxide particles. Methods: In a human inhalation study, 12 healthy adults inhaled 500 μg/m3 of ultrafine zinc oxide, the same mass of fine zinc oxide, and filtered air while at rest for 2 hours. Measurements and Main Results: Preexposure and follow-up studies of symptoms, leukocyte surface markers, hemostasis, and cardiac electrophysiology were conducted to 24 hours post-exposure. Induced sputum was sampled 24 hours after exposure. No differences were detected between any of the three exposure conditions at this level of exposure. Conclusions: Freshly generated zinc oxide in the fine or ultrafine fractions inhaled by healthy subjects at rest at a concentration of 500 μg/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints. PMID:15735058

  20. Fine-particle magnetic granulometry in an ash-flow tuff

    NASA Astrophysics Data System (ADS)

    Till, J. L.; Jackson, M. J.; Rosenbaum, J. G.; Solheid, P.

    2012-04-01

    The Tiva Canyon Tuff at Yucca Mountain in the southwestern U.S. is a welded ashflow deposit containing nanoscale Fe-oxide grains that approximate ideal assemblages of narrowly sized non-interacting magnetic particles. The low-impurity magnetite microcrystals exsolved from volcanic glass in the basal 5 m section of the tuff and display a continuous variation in grain size with stratigraphic height due to differential cooling rates in the unit. These rocks can potentially serve as useful reference material for determining fine magnetic particle grain size from size-sensitive magnetic properties in environmental and rock magnetic studies. A detailed magnetic characterization of this section revealed a distinctive magnetic signature at each stratigraphic level in the section corresponding to different grain-size distributions, with salient transitions in room temperature magnetic susceptibility and remanence that denote the spatial limits of stable single domain behavior. The progression in magnetic grain size and domain state from superparamagnetic grains near the base to pseudo-single domain grains near the top of the section, inferred from fundamental magnetic properties, are also indicated by thermal fluctuation tomography as well as previous electron microscope observations. These rocks constitute a unique natural example of weakly interacting fine magnetic particle assemblages that display clear grain-size-dependent magnetic properties over a broad range of grain sizes.

  1. Fine particle clay catalysts for coal liquefaction. Quarterly technical report, May 9, 1991--August 8, 1991

    SciTech Connect

    Olson, E.S.

    1991-12-31

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

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

    NASA Astrophysics Data System (ADS)

    Perrone, M. R.; Burlizzi, P.; De Tomasi, F.; Chaikovsky, A.

    2014-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  4. Bioaccessibility of trace elements in fine and ultrafine atmospheric particles in an industrial environment.

    PubMed

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

    2015-10-01

    The lung bioaccessibility, i.e., the solubility in alveolar lung fluid of metals in particulate matter, has been recognized as an important parameter for health risk assessment, associated with the inhalation of airborne particles. The purpose of this study is to use an in vitro method to estimate the pulmonary bioaccessibility of toxic metals in different particle sizes, from a multi-influenced industrial emission area. The fine and ultrafine particles collected with cascade impactors in the chimneys and at different distances from a Fe-Mn smelter were extracted with a simulated alveolar fluid (Gamble solution). In addition, a four-step sequential extraction procedure was employed to approach the metal speciation. The bioaccessibility of metals ranged from almost insoluble for Fe (<1%) to extremely soluble for Rb (>80%). In terms of particle size, the trace element bioaccessibility is generally higher for the finer size fractions (submicron and ultrafine particles) than for the coarse one (>1 µm). These submicron particles have a very high number concentration and specific surface area, which confer them an important contact surface with the alveolar fluid, i.e., a higher bioaccessibility. Interestingly, the bioaccessibility of most metals clearly increases between the chimney stacks and the close environment of the studied Fe-Mn smelter, over a very short distance (800 m), possibly due to a mix with surrounding steelworks emissions. This increase is not observed over a greater distance from the smelter (2000 m), when industrial particles were mixed with urban aerosols, except for Fe, under more soluble forms in combustion particles.

  5. Molecular Weight Dependence of Synthetic Glycopolymers on Flocculation and Dewatering of Fine Particles.

    PubMed

    Lu, Han; Xiang, Li; Cui, Xin; Liu, Jing; Wang, Yinan; Narain, Ravin; Zeng, Hongbo

    2016-11-08

    In this study, poly(2-lactobionamidoethyl methacrylamide) of various molecular weights (MWs) was synthesized using conventional free-radical polymerization. The effect of MW and polymer dosage on the settling rate of kaolin particles, turbidity of the supernatant, mud-line position, and solid content was investigated to determine the flocculation performance. The interaction forces, polymer conformation, particle sizes, and MWs were determined using several techniques, including surface forces apparatus, atomic force microscopy (AFM), dynamic light scattering, and gel permeation chromatography. Our results reveal that the initial settling rate of kaolin particles and the clarity of supernatants increase with increasing MW of the glycopolymers. Surface force measurements and AFM imaging of the adsorbed polymer surfaces show strong polymer-particle adhesion and bridging attraction between the glycopolymers and clay surfaces, which increase with increasing MW of the glycopolymer. The strengthened bridging attraction with the polymer MW is attributed to the formation of stronger adhesion (e.g., via hydrogen bonding) between the fine particles and the abundant hydroxyl groups in the glycopolymers of higher MW, thus contributing to enhanced flocculation behaviors. Our results provide new insights into the development of eco-friendly polymer flocculants based on glycopolymers for an efficient solid-liquid separation in tailing treatment and into the fundamental understanding of associated intermolecular interactions and flocculation mechanisms.

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

    PubMed

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

    2016-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

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

    PubMed

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

    2009-08-15

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

  9. Accretion of Fine Particles: Sticking Probability Estimated by Optical Sizing of Fractal Aggregates

    NASA Astrophysics Data System (ADS)

    Sugiura, N.; Higuchi, Y.

    1993-07-01

    Sticking probability of fine particles is an important parameter that determines (1) the settling of fine particles to the equatorial plane of the solar nebula and hence the formation of planetesimals, and (2) the thermal structure of the nebula, which is dependent on the particle size through opacity. It is generally agreed that the sticking probability is 1 for submicrometer particles, but at sizes larger than 1 micrometer, there exist almost no data on the sticking probability. A recent study [1] showed that aggregates (with radius from 0.2 to 2 mm) did not stick when collided at a speed of 0.15 to 4 m/s. Therefore, somewhere between 1 micrometer and 200 micrometers, sticking probabilities of fine particles change from nearly 1 to nearly 0. We have been studying [2,3] sticking probabilities of dust aggregates in this size range using an optical sizing method. The optical sizing method has been well established for spherical particles. This method utilizes the fact that the smaller the size, the larger the angle of the scattered light. For spheres with various sizes, the size distribution is determined by solving Y(i) = M(i,j)X(j), where Y(i) is the scattered light intensity at angle i, X(j) is the number density of spheres with size j, and M(i,j) is the scattering matrix, which is determined by Mie theory. Dust aggregates, which we expect to be present in the early solar nebula, are not solid spheres, but probably have a porous fractal structure. For such aggregates the scattering matrix M(i,j) must be determined by taking account of all the interaction among constituent particles (discrete dipole approximation). Such calculation is possible only for very small aggregates, and for larger aggregates we estimate the scattering matrix by extrapolation, assuming that the fractal nature of the aggregates allows such extrapolation. In the experiments using magnesium oxide fine particles floating in a chamber at ambient pressure, the size distribution (determined by

  10. Large scale transport of fine sulfur particles in the intermontane United States

    NASA Astrophysics Data System (ADS)

    Ashbaugh, L. L.

    This research was undertaken to study the patterns and modes of transport of fine sulfur particles in the western United States. Particles were collected in two size ranges using stacked filter samplers at 40 remote sampling sites in Montana, North and South Dakota. Wyoming, Utah, Colorado, Arizona, and New Mexico. Meteorological data were obtained from the National Climatic Center. Two three-day samples were collected each week for two years. Eulerian transort fields were determined by combining the measured concentrations with the meteorological data. An empirical orthogonal function analysis was carried out to determine spatial patterns in the sulfur variability. A statistical Lagrangian trajectory analysis was carried out usng 1980 data to determine surce regions for clean and polluted air arriving at two sites. Finally, a preliminary diffusion model calculation was made to test the theory against measured concentrations. Maps of sulfur concentrations, wind fields, and mean and synoptic scale eddy transport fields are presented for several averaging periods.

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

    NASA Astrophysics Data System (ADS)

    van Bergen, S. K.; Holmén, B. A.

    2001-12-01

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

  12. Study of structure and magnetic properties of Ni-Zn ferrite nano-particles synthesized via co-precipitation and reverse micro-emulsion technique

    NASA Astrophysics Data System (ADS)

    Abdullah Dar, M.; Shah, Jyoti; Siddiqui, W. A.; Kotnala, R. K.

    2014-08-01

    Nano-crystalline Ni-Zn ferrites were synthesized by chemical co-precipitation and reverse micro-emulsion technique with an average crystallite size of 11 and 6 nm, respectively. The reverse micro-emulsion method has been found to be more appropriate for nano-ferrite synthesis as the produced particles are monodisperse and highly crystalline. Zero-field cooled and field cooled magnetization study under different magnetic fields and magnetic hysteresis loops at different temperatures have been performed. The non-saturated M-H loops, absence of hysteresis, and coercivity at room temperature are indicative of the presence of super paramagnetic and single-domain nano-particles for both the materials. In sample `a', the blocking temperature ( T B) has been observed to decrease from 255 to 120 K on increasing the magnetic field from 50 to 1,000 Oe, which can be attributed to the reduction of magneto crystalline anisotropy constant. The M S and coercivity were found to be higher for sample `a' as compared with sample `b' since surface effects are neglected on increasing the crystallite size.

  13. Comparison of POLDER Derived Aerosol Optical Thickness to Surface Monitor Fine Particle Concentration

    NASA Astrophysics Data System (ADS)

    Leon, J.; Kacenelenbogen, M.; Chiapello, I.

    2005-12-01

    The Particulate Matter (PM) mass measured at the ground level is a common way to quantify the amount of aerosol particles in the atmosphere and is used as a standard to evaluate air quality. Satellite remote sensing is well suited for a daily monitoring of the aerosol load. However, there are no straightforward relationship between aerosol optical properties derived from the satellite sensor and the PM mass at the ground. This paper is focused on the use of Polarization and Directionality of Earth's Reflectance (POLDER-2) derived aerosol optical thickness (AOT) for the monitoring of PM2.5. We present a correlation study between PM2.5 data collected in the frame of the French Environmental protection agency, aerosol optical properties derived from Sun photometer measurements, and POLDER derived-AOT over the land. POLDER AOT retrieval algorithm over the land is based on the use of the measurement of the linear polarized light in the 670 nm and 865 nm channels. We show that only the fine fraction (below 0.3 μm) of the aerosol size distribution contributes to the signal in polarization and then to the POLDER derived-AOT and then is well suited for monitoring of fine particle. The correlation between POLDER AOT and PM2.5 is significant (R between 0.6 and 0.7) over several sites. We present a tentative evaluation of Air Quality Categories from satellite data.

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

    PubMed

    Wolthers, Ole D

    2016-02-01

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

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

    PubMed

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

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of <2mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles. Zn-Cu, Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products. Copyright © 2014. Published by Elsevier B.V.

  16. Fine and ultrafine particles generated during fluidized bed combustion of different solid fuels

    SciTech Connect

    Urciuolo, M.; Barone, A.; D'Alessio, A.; Chirone, R.

    2008-12-15

    The paper reports an experimental study carried out with a 110-mm ID fluidized bed combustor focused on the characterization of particulates formation/emission during combustion of coal and non-fossil solid fuels. Fuels included: a bituminous coal, a commercial predried and granulated sludge (GS), a refuse-derived fuel (RDF), and a biomass waste (pine seed shells). Stationary combustion experiments were carried out analyzing the fate of fuel ashes. Fly ashes collected at the combustor exhaust were characterized both in terms of particle size distribution and chemical composition, with respect to both trace and major elements. Tapping-Mode Atomic Force Microscopy (TM-AFM) technique and high-efficiency cyclone-type collector devices were used to characterize the size and morphology of the nanometric-and micronic-size fractions of fly ash emitted at the exhaust respectively. Results showed that during the combustion process: I) the size of the nanometric fraction ranges between 2 and 65 nm; ii) depending on the fuel tested, combustion-assisted attrition or the production of the primary ash particles originally present in the fuel particles, are responsible of fine particle generation. The amount in the fly ash of inorganic compounds is larger for the waste-derived fuels, reflecting the large inherent content of these compounds in the parent fuels.

  17. Environmental and health impacts of fine and ultrafine metallic particles: assessment of threat scores.

    PubMed

    Goix, Sylvaine; Lévêque, Thibaut; Xiong, Tian-Tian; Schreck, Eva; Baeza-Squiban, Armelle; Geret, Florence; Uzu, Gaëlle; Austruy, Annabelle; Dumat, Camille

    2014-08-01

    This study proposes global threat scores to prioritize the harmfulness of anthropogenic fine and ultrafine metallic particles (FMP) emitted into the atmosphere at the global scale. (Eco)toxicity of physicochemically characterized FMP oxides for metals currently observed in the atmosphere (CdO, CuO, PbO, PbSO(4), Sb(2)O(3), and ZnO) was assessed by performing complementary in vitro tests: ecotoxicity, human bioaccessibility, cytotoxicity, and oxidative potential. Using an innovative methodology based on the combination of (eco)toxicity and physicochemical results, the following hazard classification of the particles is proposed: CdCl2~CdO>CuO>PbO>ZnO>PbSO(4)>Sb(2)O(3). Both cadmium compounds exhibited the highest threat score due to their high cytotoxicity and bioaccessible dose, whatever their solubility and speciation, suggesting that cadmium toxicity is due to its chemical form rather than its physical form. In contrast, the Sb(2)O(3) threat score was the lowest due to particles with low specific area and solubility, with no effects except a slight oxidative stress. As FMP physicochemical properties reveal differences in specific area, crystallization systems, dissolution process, and speciation, various mechanisms may influence their biological impact. Finally, this newly developed and global approach could be widely used in various contexts of pollution by complex metal particles and may improve risk management. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. A pilot study to characterize fine particles in the environment of an automotive machining facility.

    PubMed

    Sioutas, C

    1999-04-01

    The main goal of this study was to characterize fine particles (e.g., smaller than about 3 microns) in an automotive machining environment. The Toledo Machining Plant of Chrysler Corporation was selected for this purpose. The effect of local mechanical processes as aerosol sources was a major part of this investigation. To determine the size-dependent mass concentration of particles in the plant, the Micro-Orifice Uniform Deposit Impactor (MOUDI Model 100, MSP Corp., Minneapolis, Minnesota) was used. The MOUDI was placed at central locations in departments with sources inside the plant, so that the obtained information on the size distribution realistically represents the aerosol to which plant workers are exposed. Sampling was conducted over a 4-day period, and during three periods per day, each matching the work shifts. A special effort was made to place the MOUDI at a central location of a department with relatively homogeneous particle sources. The selected sampling sites included welding, grinding, steel machining, and heat treating processes. The average 24-hour mass concentrations of particles smaller than 3.2 microns in aerodynamic diameter were 167.8, 103.9, 201.7, and 112.7 micrograms/m3 for welding, grinding, mild steel, and heat treating processes, respectively. Finally, the mass median diameters of welding, heat treatment, machining, and grinding operations were approximately 0.5, 0.5, 0.6, and 0.8 micron, respectively.

  19. Source strengths of ultrafine and fine particles due to cooking with a gas stove.

    PubMed

    Wallace, Lance A; Emmerich, Steven J; Howard-Reed, Cynthia

    2004-04-15

    Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes, including ultrafine particles, produced during cooking. In this study, semicontinuous instruments with fine size discriminating ability were used to calculate particle counts in 124 size bins from 0.01 to 2.5 microm. Data were collected at 5 min intervals for 18 months in an occupied house. Tracer gas measurements were made every 10 min in each of 10 rooms of the house to establish air change rates. Cooking episodes (N = 44) were selected meeting certain criteria (high concentrations, no concurrent indoor sources, long smooth decay curves), and the number and volume of particles produced were determined for each size category. For each episode, the particle decay rate was determined and used to determine the source strength for each size category. The selected cooking episodes (mostly frying) were capable of producing about 10(14) particles over the length of the cooking period (about 15 min), more than 90% of them in the ultrafine (< 0.1 microm) range, with an estimated whole-house volume concentration of 50 (microm/cm)3. More than 60% of this volume occurred in the 0.1-0.3 microm range. Frying produced peak numbers of particles at about 0.06 microm, with a secondary peak at 0.01 microm. The peak volume occurred at a diameter of about 0.16 microm. Since the cooking episodes selected were biased toward higher concentrations, the particle concentrations measured during about 600 h of morning and evening cooking over a full year were compared to concentrations measured during noncooking periods at the same times. Cooking was capable of producing more than 10 times the ultrafine particle number observed during noncooking periods. Levels of PM2.5 were increased during cooking by a factor of 3. Breakfast cooking (mainly heating water for coffee and using an electric toaster) produced concentrations about half those produced from more

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

    NASA Astrophysics Data System (ADS)

    Delmelle, Pierre; Villiéras, Frédéric; Pelletier, Manuel

    2005-02-01

    Our understanding on how ash particles in volcanic plumes react with coexisting gases and aerosols is still rudimentary, despite the importance of these reactions in influencing the chemistry and dynamics of a plume. In this study, six samples of fine ash (<100 μm) from different volcanoes were measured for their specific surface area, as, porosity and water adsorption properties with the aim to provide insights into the capacity of silicate ash particles to react with gases, including water vapour. To do so, we performed high-resolution nitrogen and water vapour adsorption/desorption experiments at 77 K and 303 K, respectively. The nitrogen data indicated as values in the range 1.1 2.1 m2/g, except in one case where a as of 10 m2/g was measured. This high value is attributed to incorporation of hydrothermal phases, such as clay minerals, in the ash surface composition. The data also revealed that the ash samples are essentially non-porous, or have a porosity dominated by macropores with widths >500 Å. All the specimens had similar pore size distributions, with a small peak centered around 50 Å. These findings suggest that fine ash particles have relatively undifferentiated surface textures, irrespective of the chemical composition and eruption type. Adsorption isotherms for water vapour revealed that the capacity of the ash samples for water adsorption is systematically larger than predicted from the nitrogen adsorption as values. Enhanced reactivity of the ash surface towards water may result from (i) hydration of bulk ash constituents; (ii) hydration of surface compounds; and/or (iii) hydroxylation of the surface of the ash. The later mechanism may lead to irreversible retention of water. Based on these experiments, we predict that volcanic ash is covered by a complete monolayer of water under ambient atmospheric conditions. In addition, capillary condensation within ash pores should allow for deposition of condensed water on to ash particles before water

  1. In vitro and in vivo assessment of pulmonary risk associated with exposure to combustion generated fine particles.

    PubMed

    Fahmy, Baher; Ding, Liren; You, Dahui; Lomnicki, Slawo; Dellinger, Barry; Cormier, Stephania A

    2010-03-01

    Strong correlations exist between exposure to PM(2.5) and adverse pulmonary effects. PM(2.5) consists of fine (particles with ultrafine particles accounting for >70% of the total particles. Environmentally persistent free radicals (EPFRs) have recently been identified in airborne PM(2.5). To determine the adverse pulmonary effects of EPFRs associated with exposure to elevated levels of PM(2.5), we engineered 2.5 mum surrogate EPFR-particle systems. We demonstrated that EPFRs generated greater oxidative stress in vitro, which was partly responsible for the enhanced cytotoxicity following exposure. In vivo studies using rats exposed to EPFRs containing particles demonstrated minimal adverse pulmonary effects. Additional studies revealed that fine particles failed to reach the alveolar region. Overall, our study implies qualitative differences between the health effects of PM size fractions.

  2. In Vitro and In Vivo Assessment of Pulmonary Risk Associated with Exposure to Combustion Generated Fine Particles

    PubMed Central

    Fahmy, Baher; Ding, Liren; You, Dahui; Lomnicki, Slawo; Dellinger, Barry; Cormier, Stephania A.

    2009-01-01

    Strong correlations exist between exposure to PM2.5 and adverse pulmonary effects. PM2.5 consists of fine (≤2.5 μm) and ultrafine (≤0.1 μm) particles with ultrafine particles accounting for >70% of the total particles. Environmentally persistent free radicals (EPFRs) have recently been identified in airborne PM2.5. To determine the adverse pulmonary effects of EPFRs associated with exposure to elevated levels of PM2.5, we engineered 2.5 μm surrogate EPFR-particle systems. We demonstrated that EPFRs generated greater oxidative stress in vitro, which was partly responsible for the enhanced cytotoxicity following exposure. In vivo studies using rats exposed to EPFRs containing particles demonstrated minimal adverse pulmonary effects. Additional studies revealed that fine particles failed to reach the alveolar region. Overall, our study implies qualitative differences between the health effects of PM size fractions. PMID:20369027

  3. Comparison of fine particle measurements from a direct-reading instrument and a gravimetric sampling method.

    PubMed

    Kim, Jee Young; Magari, Shannon R; Herrick, Robert F; Smith, Thomas J; Christiani, David C

    2004-11-01

    Particulate air pollution, specifically the fine particle fraction (PM2.5), has been associated with increased cardiopulmonary morbidity and mortality in general population studies. Occupational exposure to fine particulate matter can exceed ambient levels by a large factor. Due to increased interest in the health effects of particulate matter, many particle sampling methods have been developed In this study, two such measurement methods were used simultaneously and compared. PM2.5 was sampled using a filter-based gravimetric sampling method and a direct-reading instrument, the TSI Inc. model 8520 DUSTTRAK aerosol monitor. Both sampling methods were used to determine the PM2.5 exposure in a group of boilermakers exposed to welding fumes and residual fuel oil ash. The geometric mean PM2.5 concentration was 0.30 mg/m3 (GSD 3.25) and 0.31 mg/m3 (GSD 2.90)from the DUSTTRAK and gravimetric method, respectively. The Spearman rank correlation coefficient for the gravimetric and DUSTTRAK PM2.5 concentrations was 0.68. Linear regression models indicated that log, DUSTTRAK PM2.5 concentrations significantly predicted loge gravimetric PM2.5 concentrations (p < 0.01). The association between log(e) DUSTTRAK and log, gravimetric PM2.5 concentrations was found to be modified by surrogate measures for seasonal variation and type of aerosol. PM2.5 measurements from the DUSTTRAK are well correlated and highly predictive of measurements from the gravimetric sampling method for the aerosols in these work environments. However, results from this study suggest that aerosol particle characteristics may affect the relationship between the gravimetric and DUSTTRAK PM2.5 measurements. Recalibration of the DUSTTRAK for the specific aerosol, as recommended by the manufacturer, may be necessary to produce valid measures of airborne particulate matter.

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

    NASA Astrophysics Data System (ADS)

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

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

  5. Evaluation of fine-particle catalysts: Activity testing results and phase identification using Mossbauer spectroscopy

    SciTech Connect

    Stohl, F.V.; Diegert, K.V.; Goodnow, D.; Rao, K.R.P.M.; Huggins, F.; Huffman, G.P.

    1994-10-01

    To evaluate and compare the activities/selectivities of fine- particle size catalysts being developed in the DOE/PETC Advanced Research (AR) Coal Liquefaction program by using standard coal liquefaction activity test procedures. Previously reported results have described the standard test procedure that was developed at Sandia to evaluate fine-particle size iron catalysts being developed in DOE/PETC`s AR Coal Liquefaction Program. This test uses DECS-17 Blind Canyon Coal, phenanthrene as the reaction solvent, and a factorial experimental design that enables evaluation of a catalyst over ranges of temperature (350 to 400{degrees}C), time (20 to 60 minutes), and catalyst loading (0 to 1 wt% on a dmmf coal basis). Testing has been performed on Pacific Northwest Laboratories` (PNL) 6-line ferrihydrite catalyst. Results showed that this catalyst is more active than the University of Pittsburgh`s sulfated iron oxide catalyst that was evaluated previously. PNL has also produced two additional batches of catalyst in an effort to optimize their preparation procedures for larger batches. Sandia has observed significant differences in activities among these three catalysts; these differences might be due to particle size effects, the type of drying procedure, or the amount of moisture present. Mossbauer characterization of the iron phases in the coal, catalyst precursors, and tetrahydrofuran (THF) insoluble material from liquefaction reactions has been performed on the University of Pittsburgh`s catalyst and the first PNL catalyst that was tested at Sandia. The Mossbauer results were obtained at the University of Kentucky and will be presented. Future work will include testing additional catalysts being developed in the AR Coal Liquefaction Program, developing procedures to characterize reaction products, and determining the kinetics of the reactions.

  6. Speciation of gas-phase and fine particle emissions from burning of foliar fuels.

    PubMed

    Hays, Michael D; Geron, Christopher D; Linna, Kara J; Smith, N Dean; Schauer, James J

    2002-06-01

    Fine particle matter with aerodynamic diameter <2.5 microm (PM2.5) and gas-phase emissions from open burning of six fine (foliar) fuels common to fire-prone U.S. ecosystems are investigated. PM2.5 distribution is unimodal within the 10-450 nm range, indicative of an accumulation mode. Smoldering relative to flaming combustion shows smaller particle number density per unit time and median size. Over 100 individual organic compounds in the primarily carbonaceous (>70% by mass) PM2.5 are chemically speciated by gas chromatography/mass spectrometry. Expressed as a percent of PM2.5 mass, emission ranges by organic compound class are as follows: n-alkane (0.1-2%), polycyclic aromatic hydrocarbon (PAH) (0.02-0.2%), n-alkanoic acid (1-3%), n-alkanedioic acid (0.06-0.3%), n-alkenoic acid (0.3-3%), resin acid (0.5-6%), triterpenoid (0.2-0.5%), methoxyphenol (0.5-3%), and phytosterol (0.2-0.6%). A molecular tracer of biomass combustion, the sugar levoglucosan is abundant and constitutes a remarkably narrow PM2.5 mass range (2.8-3.6%). Organic chemical signatures in PM2.5 from open combustion of fine fuels differ with those of residential wood combustion and other related sources, making them functional for source-receptor modeling of PM. Inorganic matter [PM2.5 - (organic compounds + elemental carbon)] on average is estimated to make up 8% of the PM2.5. Wavelength dispersive X-ray fluorescence spectroscopy and ion chromatography identify 3% of PM2.5 as elements and water-soluble ions, respectively. Compared with residential wood burning, the PM2.5 of fine fuel combustion is nitrate enriched but shows lower potassium levels. Gas-phase C2-C13 hydrocarbon and C2-C9 carbonyl emissions are speciated by respective EPA Methods T0-15 and T0-11A. They comprise mainly low molecular weight C2-C3 compounds and hazardous air pollutants (48 wt % of total quantified volatile organic carbon).

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

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

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

    PubMed

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

    2012-01-01

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

  9. Attenuation of Gas Turbulence by a Nearly Stationary Dispersion of Fine Particles

    NASA Technical Reports Server (NTRS)

    Paris, A. D.; Eaton, J. K.; Hwang, W.

    1999-01-01

    particles fall through the measurement volume. Measurements will be acquired using a high resolution image velocimetry (PIV) system being developed specifically for work in particle-laden flows. The measurements will include the decay of the turbulence kinetic energy under various particle loadings. The spatial spectra of the turbulence will also be measured. In a second set of experiments, the interaction of a single eddy with a collection of nearly stationary particles will be examined. The eddy will be a vortex ring emitted by a jet pulse through an orifice. The distortion of the vortex under the influence of the particles will be examined to gain a better understanding of how fine particles can cause such large reductions in turbulence levels. This experiment could not be conducted in terrestrial gravity because the high particle velocities would overwhelm the relatively low speed motion of the vortex ring. This experimental program is just getting underway. The initial challenge is to build a closed facility containing reasonably homogeneous and isotropic turbulence with zero mean velocity. Our approach is to use a set of synthetic jets mounted on the periphery of a transparent plexiglass box to create the turbulence. A synthetic jet is a plenum chamber with an orifice open to the volume of interest. The volume of the chamber fluctuates periodically so alternately a jet is ejected from the volume or flow is drawn back in as a sink. The asymmetry of this situation results in a net transport of momentum and kinetic energy into the volume of interest. The present apparatus includes eight synthetic jets each powered independently by a six inch loudspeaker. The synthetic jets discharge through ejector tubes to increase the scale of the turbulence. Construction of the apparatus is now complete and preliminary flow visualization studies have been conducted. The PIV system is also under development. A compact dual-pulse YAG laser has been acquired as the light source and

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

    PubMed

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

    2015-06-01

    The National Aeronautics and Space Administration has announced a plan to establish a manned colony on the surface of the moon, and our country, Japan, has declared its participation. The surface of the moon is covered with soil called lunar regolith, which includes fine particles. It is possible that humans will inhale lunar regolith if it is brought into the spaceship. Therefore, an evaluation of the pulmonary effects caused by lunar regolith is important for exploration of the moon. In the present study, we examine the cellular effects of lunar regolith simulant, whose components are similar to those of lunar regolith. We focused on the chemical component and particle size in particular. The regolith simulant was fractionated to < 10 μm, < 25 μm and 10-25 μm by gravitational sedimentation in suspensions. We also examined the cellular effects of fine regolith simulant whose primary particle size is 5.10 μm. These regolith simulants were applied to human lung carcinoma A549 cells at concentrations of 0.1 and 1.0 mg/ml. Cytotoxicity, oxidative stress and immune response were examined after 24 h exposure. Cell membrane damage, mitochondrial dysfunction and induction of Interleukin-8 (IL-8) were observed at the concentration of 1.0 mg/ml. The cellular effects of the regolith simulant at the concentration of 0.1 mg/ml were small, as compared with crystalline silica as a positive control. Secretion of IL-1β and tumor necrosis factor-α (TNF-α) was observed at the concentration of 1.0 mg/ml, but induction of gene expression was not observed at 24 h after exposure. Induction of cellular oxidative stress was small. Although the cellular effects tended to be stronger in the < 10 μm particles, there was no remarkable difference. These results suggest that the chemical components and particle size have little relationship to the cellular effects of lunar regolith simulant such as cell membrane damage, induction of oxidative stress and proinflammatory effect.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    Fine (< 2.5 μm), submicron (< 1 μm) and ultrafine (< 100 nm) atmospheric particles were collected during a 3-weeks campaign in a heavily industrialized area and physically and chemically characterized in order to determine their main sources. As a basis of comparison, the present one-year average EU limit value (25 μg·m- 3) and the WHO recommendation for PM2.5 (10 μg m- 3) were regularly exceeded during this campaign. Submicron particles (PM1) account for 55 to 70% of PM2.5 mass concentrations. A bi-modal size distribution, centered on 0.4 and 2.0 μm, suggests two types of emissions: high temperature processes that liberate primary or secondary submicron particles and mechanical procedures in open air, or local traffic, which lead to the emission of coarser particles (> 1 μm). The trace elements As, Cd, Ni, Pb, Sb, V and Zn, characteristics of the local industrial activities display 60% to 85% of their mass in the submicron and ultrafine fractions and appear highly enriched, by reference to the crustal source. High atmospheric pressure periods, corresponding to northeasterly winds, induce the highest contributions of metalworking emissions and the highest PM2.5 concentrations (32.5 ± 11.9 μg·m- 3). A Principal Component Analysis of the dataset produces 7 factors associated to metallurgy-, steelworks-, oil processing-, coal combustion-, neighboring traffic-, dust resuspension- and sea salt-sources, that explain the obtained concentrations. A Multiple Linear Regression Analysis confirms that Fe-Mn alloy refining, iron- and steel-making are the main sources (> 40%) controlling metal concentrations in PM2.5. Less predictably, resuspended dust and fresh/aged sea salts are also significant contributors (≈ 20%). Considering the related health hazards, authorities should pay more attention to the exposure of people living in this area and the possible impact of fine particles in terms of public health.

  12. The preparation of copper fine particle paste and its application as the inner electrode material of a multilayered ceramic capacitor

    NASA Astrophysics Data System (ADS)

    Yonezawa, Tetsu; Takeoka, Shinsuke; Kishi, Hiroshi; Ida, Kiyonobu; Tomonari, Masanori

    2008-04-01

    Well size-controlled copper fine particles (diameter: 100-300 nm) were used as the inner electrode material of multilayered ceramic capacitors (MLCCs). The particles were dispersed in terpineol to form a printing paste with 50 wt% copper particles. The MLCC precursor modules prepared by the layer-by-layer printing of copper and BaTiO3 particles were cosintered. Detailed observation of the particles, paste, and MLCCs before and after sintering was carried out by electron microscopy. The sintering temperature of Cu-MLCC was as low as 960 °C. The permittivity of these MLCCs was successfully measured with the copper inner layers.

  13. Geochemical and petrographical characterization of fine-grained carbonate particles along proximal to distal transects

    NASA Astrophysics Data System (ADS)

    Turpin, Mélanie; Emmanuel, Laurent; Immenhauser, Adrian; Renard, Maurice

    2012-12-01

    The origin of carbonate ooze particles is often poorly understood. This is due to their polygenic origin and potential post-depositional alteration. Here, the outcome of a physical separation study with regard to different component classes of micritic carbonates is shown. The focus is on grain size and morphology, mineralogy and isotope signatures. Two contrasting proximal-to-distal transects were investigated: (1) the Miocene leeward margin of Great Bahama Bank (ODP Leg 166) and (2) the transition between the Maiella platform and the Umbria-Marche basin in central Italy near the Cenomanian-Turonian boundary. In both case settings, carbonate particles of biogenic origin include at least three groups of organisms: (i) planktonic foraminifera, (ii) calcareous nannofossils and (iii) fragments of unspecified neritic skeletal material. Two further particle types lack diagnostic structures, and based on particle size and mineralogy, are here referred to as (iv) macroparticles (5-20 μm, mainly xenomorphic) and (v) microparticles (< 12 μm, mainly automorphic to sub-automorphic). Macro- and microparticles represent 50 to 80% of the carbonate phase in slope and toe-of-slope domains and share characteristic carbon and oxygen isotope signatures. Macro- and microparticles are considered shallow-water precipitation products subsequently exported into the slope and toe-of-slope domains. Macroparticles are probably related to the fragmentation of neritic skeletal components while microparticles point to inorganic and/or bioinduced precipitation in the water column. In some cases, macro- and microparticles may have an early diagenetic origin. The identification of the origin of fine-grained particles allows for a quantitative assessment of exported, in situ and diagenetic carbonate materials in periplatform environments. The data shown here represent an important step towards a more complete characterization of carbonate ooze and micrite.

  14. Observations of Fine and Coarse Particle Nitrate at Several Rural Locations in the United States

    SciTech Connect

    Lee, Taehyoung; Yu, Xiao-Ying; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

    2008-04-01

    Nitrate comprises an important part of aerosol mass at many non-urban locations during some times of the year. Little is known, however, about the chemical form and size distribution of particulate nitrate in these environments. While submicron ammonium nitrate is often assumed to be the dominant species, this assumption is rarely tested. Properties of aerosol nitrate were characterized at several IMPROVE monitoring sites during a series of field studies. Study sites included Bondville, Illinois (February 2003), San Gorgonio Wilderness Area, California (April and July 2003), Grand Canyon National Park, Arizona (May 2003), Brigantine National Wildlife Refuge, New Jersey (November 2003), and Great Smoky Mountains National Park, Tennessee (July/August 2004). Nitrate was found predominantly in submicron ammonium nitrate particles during the Bondville and San Gorgonio (April) campaigns. Coarse mode nitrate particles, resulting from reactions of nitric acid or its precursors with sea salt or soil dust, were more important at Grand Canyon and Great Smoky Mountains. Both fine and coarse mode nitrate were important during the studies at Brigantine and San Gorgonio (July). These results, which complement earlier findings about the importance of coarse particle nitrate at Yosemite and Big Bend National Parks, suggest a need to more closely examine common assumptions regarding the importance of ammonium nitrate at non-urban sites, to include pathways for coarse mode nitrate formation in regional models, and to consider impacts of coarse particle nitrate on visibility. Because coarse particle nitrate modes often extend well below 2.5 µm aerodynamic diameter, measurements of PM2.5 nitrate in these environments should not automatically be assumed to contain only ammonium nitrate.

  15. Observations of fine and coarse particle nitrate at several rural locations in the United States

    NASA Astrophysics Data System (ADS)

    Lee, Taehyoung; Yu, Xiao-Ying; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

    Nitrate comprises an important part of aerosol mass at many non-urban locations during some times of the year. Little is known, however, about the chemical form and size distribution of particulate nitrate in these environments. While submicron ammonium nitrate is often assumed to be the dominant species, this assumption is rarely tested. Properties of aerosol nitrate were characterized at several IMPROVE monitoring sites during a series of field studies. Study sites included Bondville, Illinois (February 2003), San Gorgonio Wilderness Area, California (April and July 2003), Grand Canyon National Park, Arizona (May 2003), Brigantine National Wildlife Refuge, New Jersey (November 2003), and Great Smoky Mountains National Park, Tennessee (July/August 2004). Nitrate was found predominantly in submicron ammonium nitrate particles during the Bondville and San Gorgonio (April) campaigns. Coarse mode nitrate particles, resulting from reactions of nitric acid or its precursors with sea salt or soil dust, were more important at Grand Canyon and Great Smoky Mountains. Both fine and coarse mode nitrate were important during the studies at Brigantine and San Gorgonio (July). These results, which complement earlier findings about the importance of coarse particle nitrate at Yosemite and Big Bend National Parks, suggest a need to more closely examine common assumptions regarding the importance of ammonium nitrate at non-urban sites, to include pathways for coarse mode nitrate formation in regional models, and to consider impacts of coarse particle nitrate on visibility. Because coarse particle nitrate modes often extend well below 2.5 μm aerodynamic diameter, measurements of PM 2.5 nitrate in these environments should not automatically be assumed to contain only ammonium nitrate.

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

    SciTech Connect

    Goix, Sylvaine; Lévêque, Thibaut; Xiong, Tian-Tian; Schreck, Eva; and others

    2014-08-15

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

  17. The grape cluster, metal particle 63344,1. [in lunar coarse fines

    NASA Technical Reports Server (NTRS)

    Goldstein, J. I.; Axon, H. J.; Agrell, S. O.

    1975-01-01

    The grape cluster metal particle 63344,1 found in lunar coarse fines is examined using the scanning electron microscope (SEM), electron microprobe, and an optical microscope. This metal particle is approximately 0.5 cm in its largest dimension and consists of hundreds of metallic globules welded together to form a structure somewhat like a bunch of grapes. Electron microprobe analysis for Fe, Ni, Co, P, and S in the metal was carried out using wavelength dispersive detectors. No primary solidification structure is observed in the globules, and the particle is slow cooled from the solidification temperature (nearly 1300 C) taking days to probably months to reach 600 C. Two mechanisms for the formation of globules are proposed. One mechanism involves the primary impact of an iron meteorite which produces a metallic liquid and vapor phase. The second mechanism involves the formation of a liquid pool of metal after impact of an iron meteorite projectile followed by a secondary impact in the liquid metal pool.

  18. Enhanced control of fine particles following Title IV coal switching and NOx control

    SciTech Connect

    Durham, M.D.; Baldrey, K.E.; Bustard, C.J.; Martin, C.

    1997-12-31

    Electrostatic precipitators (ESPs) serve as the primary particle control devices for a majority of coal-fired power generating units in the United States. ESPs are used to collect particulate matter that range in size from less than one micrometer in diameter to several hundred micrometers. Many of the options that utilities will use to respond to Title IV of the 1990 Clean Air Act Amendments will result in changes to the ash that will be detrimental to the performance of the ESP causing increased emissions of fine particles and higher opacity. For example, a switch to low-sulfur coal significantly increases particle resistivity while low-NO{sub x} burners increase the carbon content of ashes. Both of these changes could result in derating of the boiler to comply with emissions standards. ADA has developed a chemical additive that is designed to improve the operation of ESI`s to bring these systems into compliance operation without the need for expensive capital modifications. The additives provide advantages over competing technologies in terms of low capital cost, easy to handle chemicals, and relatively non-toxic chemicals. In addition, the new additive is insensitive to ash chemistry which will allow the utility complete flexibility to select the most economical coal. Results from full-scale and pilot plant demonstrations are reported.

  19. Seasonal variation of ionic species in fine particles at Qingdao, China

    NASA Astrophysics Data System (ADS)

    Hu, Min; He, Ling-Yan; Zhang, Yuan-Hang; Wang, Min; Pyo Kim, Yong; Moon, K. C.

    Totally nine measurement campaigns for ambient particles and SO 2 have been conducted during the period of 1997-2000 in Qingdao in order to understand the characteristics of the particulate matter in coastal areas of China. The mass fractions of PM 2.5, PM 2.5-10 and PM >10 in TSP are 49%, 25% and 26%, respectively. The size distribution of particles mass concentrations in Qingdao shows bi-modal distribution. Mass fraction percentages of water-soluble ions in PM 2.5, PM 2.5-10 and PM >10 decreased from 62% to 35% and 21%. In fine particles, sulfate, nitrate and ammonium, secondary formed compounds, are major components, totally accounting for 50% of PM 2.5 mass concentration. The ratios of sulfate, chloride, ammonium and potassium in PM 2.5 for heating versus non-heating periods are 1.34, 1.80, 1.56 and 1.44, respectively. The ratio of nitrate is 3.02 and this high ratio could be caused by reduced volatilization at lower temperature. Sulfate concentrations are higher than nitrate in PM 2.5. The chemical forms of sulfate and nitrate are probably (NH 4) 2SO 4 and NH 4NO 3 and chloride depletion was observed. Backward trajectory analysis reflected possible influence of air pollutant transport to Qingdao local aerosol pollution.

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

    NASA Astrophysics Data System (ADS)

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

    2001-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed

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

    2016-03-01

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

  3. Fine Adjustment of Interfacial Potential between pH-Responsive Hydrogels and Cell-Sized Particles.

    PubMed

    Monzel, Cornelia; Veschgini, Mariam; Madsen, Jeppe; Lewis, Andrew L; Armes, Steven P; Tanaka, Motomu

    2015-08-11

    We quantitatively determined interfacial potentials between cell-sized particles and stimulus-responsive hydrogels using a microinterferometer. The hydrogel is based on physically interconnected ABA triblock copolymer micelles comprising an inner biocompatible PMPC block and two outer pH-responsive PDPA blocks. The out-of-plane temporal fluctuation in the position of the cell-sized particles was calculated from changes in the interference pattern measured by Reflection Interference Contrast Microscopy (RICM), thus yielding the particle-substrate interaction potential V (Δh). Measurements in pH buffers ranging from 7.0 to 7.8 resulted in a systematic reduction in height of the potential minima ⟨Δh⟩ and a concomitant increase in the potential curvature V″ (Δh). The experimental data were analyzed by applying the modified Ross and Pincus model for polyelectrolytes, while accounting for gravitation, lubrication and van der Waals interactions. Elastic moduli calculated from V″ (Δh) were in good agreement with those measured by Atomic Force Microscopy. The ability to fine-tune both the gel elasticity and the interfacial potential at around physiological pH makes such triblock copolymer hydrogels a promising biocompatible substrate for dynamic switching of cell-material interactions.

  4. Qualitative investigation of uptake of fine particle size microcrystalline cellulose following oral administration in rats.

    PubMed Central

    Kotkoskie, L A; Butt, M T; Selinger, E; Freeman, C; Weiner, M L

    1996-01-01

    A subchronic toxicity study was conducted to evaluate the potential toxicological effects associated with intestinal translocation of a special fine particle size (median particle size 6 microns) microcrystalline cellulose (MCC). Four groups of Sprague-Dawley rats (20/sex/group) received either 0 (control), 500, 2500 or 5000 mg/kg/day MCC (25% w/v in tap water) daily by oral gavage for 90 d. At study termination, organs and tissues from high-dose and control animals, including multiple sections of intestine with gut-associated lymphoid tissue, were processed for light microscopy with subsequent examination under polarised light for the presence of birefringent MCC particles. None were observed in any tissue examined. No toxicologically significant effects or lesions were found in any other parameter or organ evaluated. The 'no observed adverse effect level' (NOAEL) for toxicological effects was greater than 5000 mg/kg/day MCC, which was the highest dosage tested. These results further verify the safety of commercial MCC products for use in food and pharmaceutical applications. Images Fig. 1 Fig. 2 Fig. 3 PMID:8982827

  5. Toxicity of chemical components of fine particles inhaled by aged rats: effects of concentration.

    PubMed

    Kleinman, Michael T; Hyde, Dallas M; Bufalino, Charles; Basbaum, Carol; Bhalla, Deepak K; Mautz, William J

    2003-09-01

    This study tested the hypothesis that exposure to mixtures containing fine particles and ozone (O3) would cause pulmonary injury and decrements in functions of immunological cells in exposed rats (22-24 months old) in a dose-dependent manner. Rats were exposed to high and low concentrations of ammonium bisulfate and elemental carbon and to 0.2 ppm O3. Control groups were exposed to purified air or O3 alone. The biological end points measured included histopathological markers of lung injury, bronchoalveolar lung fluid proteins, and measures of the function of the lung's innate immunological defenses (macrophage antigen-directed phagocytosis and respiratory burst activity). Exposure to O3 alone at 0.2 ppm did not result in significant changes in any of the measured end points. Exposures to the particle mixtures plus O3 produced statistically significant changes consistent with adverse effects. The low-concentration mixture produced effects that were statistically significant compared to purified air but, with the exception of macrophage Fc receptor binding, exposure to the high-concentration mixture did not. The effects of the low- and high-concentration mixtures were not significantly different. The study supports previous work that indicated that particle + O3 mixtures were more toxic than O3 alone.

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

    PubMed

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

    2009-02-01

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

  7. Generation of Hydroxyl Radicals from Ambient Fine Particles in a Surrogate Lung Fluid Solution

    PubMed Central

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

    2008-01-01

    While it has been hypothesized that the adverse health effects associated with ambient particulate matter (PM) are due to production of hydroxyl radical (·OH), few studies have quantified ·OH production from PM. Here we report the amounts of ·OH produced from ambient fine particles (PM2.5) collected in northern California and extracted in a cell-free surrogate lung fluid (SLF). On average, the extracted particles produced 470 nmol ·OH mg−1-PM2.5 during our 15-month collection period. There was a clear seasonal pattern in the efficiency with which particles generated ·OH, with highest production during spring and summer and lowest during winter. In addition, nighttime PM was typically more efficient than daytime PM at generating ·OH. Transition metals played the dominant role in ·OH production: on average (± σ), the addition of desferoxamine (a chelator that prevents metals from forming ·OH) to the SLF removed (90 ± 5) % of ·OH generation. Furthermore, based on the concentrations of Fe in the PM2.5 SLF extracts, and the measured yield of ·OH as a function of Fe concentration, dissolved iron can account for the majority of ·OH produced in most of our PM2.5 extracts. PMID:19245037

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

    PubMed

    Yonezawa, Tetsu; Uchida, Yoshiki; Tsukamoto, Hiroki

    2015-12-28

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

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

    SciTech Connect

    Jost O.L. Wendt

    2003-06-02

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process.

  10. TEM and HRTEM study of oxide particles in an Al-alloyed high-Cr oxide dispersion strengthened ferritic steel with Hf addition

    NASA Astrophysics Data System (ADS)

    Dou, Peng; Kimura, Akihiko; Kasada, Ryuta; Okuda, Takanari; Inoue, Masaki; Ukai, Shigeharu; Ohnuki, Somei; Fujisawa, Toshiharu; Abe, Fujio; Jiang, Shan; Yang, Zhigang

    2017-03-01

    The nanoparticles in an Al-alloyed high-Cr oxide dispersion strengthened (ODS) ferritic steel with Hf addition, i.e., SOC-16 (Fe-15Cr-2W-0.1Ti-4Al-0.62Hf-0.35Y2O3), have been examined by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Relative to an Al-alloyed high-Cr ODS ferritic steel without Hf addition, i.e., SOC-9 (Fe-15.5Cr-2W-0.1Ti-4Al-0.35Y2O3), the dispersion morphology and coherency of the oxide nanoparticles in SOC-16 were significantly improved. Almost all the small nanoparticles (diameter <10 nm) in SOC-16 were found to be consistent with cubic Y2Hf2O7 oxides with the anion-deficient fluorite structure and coherent with the bcc steel matrix. The larger particles (diameter >10 nm) were also mainly identified as cubic Y2Hf2O7 oxides with the anion-deficient fluorite structure. The results presented here are compared with those of SOC-9 with a brief discussion of the underlying mechanisms of the unusual thermal and irradiation stabilities of the oxides as well as the superior strength, excellent irradiation tolerance and extraordinary corrosion resistance of SOC-16.

  11. Sintering effect on structural, magnetic and optical properties of Ni0.5Zn0.5Fe2O4 ferrite nano particles

    NASA Astrophysics Data System (ADS)

    Kannan, Y. B.; Saravanan, R.; Srinivasan, N.; Ismail, I.

    2017-02-01

    Ni0.5Zn0.5Fe2O4 nano ferrite particles have been prepared by mechanical alloying via high energy ball milling and sintered at different temperatures from 700 °C to 1000 °C. Spinel structure is confirmed from the analysis of XRD data. Rietveld refinement method is employed to refine the XRD powder data and the structural parameters are calculated from the refinement. Small amount of hematite phase is found in all samples. The SEM, EDAX and XRF analysis reveals respectively the morphology, stoichiometric composition and purity of the powder samples. Using Maximum Entropy Method (MEM) the values of the bond strength between various sites interactions in ferrites are evaluated and compared with theoretical predictions of strengthening/weakening of various sites interactions from the values of interionic distances and interionic bond angles. Ferromagnetic nature of the samples is confirmed from the vibrating sample magnetometer study. The obtained low saturation magnetization values are attributed to presence of second phase. The optical band gap energy of the samples was determined by using UV-VIS techniques.

  12. Effect of Fine Particle Peening on Oxidation Resistance of Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kikuchi, Shoichi; Yasutake, Yujiro; Komotori, Jun

    Fine particle peening (FPP) treatment was introduced to improve the oxidation resistance of austenitic stainless steel. After FPP treatment, oxidation tests were performed at 700 and 800 °C for 1, 4 and 12 h in an atmospheric environment. The surface microstructures of the oxidized specimens were observed using optical microscopy, scanning electron microscopy (SEM), glow discharge optical emission spectroscopy (GD-OES), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The amount of oxygen diffused into the FPP-treated specimens was significantly less than that into un-peened specimens. Iron oxides were formed in the un-peened specimens as a result of the oxidation tests. In contrast, a protective chromium oxide layer was created on the FPP-treated surface, because the fine grains and dislocations induced by FPP treatment accelerated the diffusion of chromium during the subsequent oxidation tests. These results indicate that FPP treatment is a very efficient process to improve the atmospheric oxidation resistance of austenitic stainless steel.

  13. Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow

    PubMed Central

    Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

    2013-01-01

    We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system. PMID:23378921

  14. Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.

    PubMed

    Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

    2013-01-01

    We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system.

  15. Aerosol Measurements of the Fine and Ultrafine Particle Content of Lunar Regolith

    NASA Technical Reports Server (NTRS)

    Greenberg, Paul S.; Chen, Da-Ren; Smith, Sally A.

    2007-01-01

    We report the first quantitative measurements of the ultrafine (20 to 100 nm) and fine (100 nm to 20 m) particulate components of Lunar surface regolith. The measurements were performed by gas-phase dispersal of the samples, and analysis using aerosol diagnostic techniques. This approach makes no a priori assumptions about the particle size distribution function as required by ensemble optical scattering methods, and is independent of refractive index and density. The method provides direct evaluation of effective transport diameters, in contrast to indirect scattering techniques or size information derived from two-dimensional projections of high magnification-images. The results demonstrate considerable populations in these size regimes. In light of the numerous difficulties attributed to dust exposure during the Apollo program, this outcome is of significant importance to the design of mitigation technologies for future Lunar exploration.

  16. Preparation and Characterization of Fine-Particle NTO and Its Formulation with Al Nanopowders

    NASA Astrophysics Data System (ADS)

    Lee, K.-Y.; Kennedy, J. E.; Asay, B. W.; Son, S. F.; Martin, E. S.

    2004-07-01

    We have initiated study of the effect of nano-aluminum on the detonation performance of NTO. A novel method for the preparation of both fine-particle NTO (UF-NTO) and its formulation with Al nanopowder has been developed. Results from small-scale sensitivity tests on both the UF-NTO and aluminized NTO composite indicated that they are insensitive to impact, friction and HESD. The performance of both UF-NTO and NTO/Al mix was evaluated by detonation-spreading floret tests. At the same pressed density, it was found that, when initiated by a 3-mm-diameter flyer plate, the aluminized NTO composite produced a shallower dent on a copper witness plate than neat UF-NTO and thus was inferior to UF-NTO in detonation spreading.

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

    SciTech Connect

    Rajan, S.

    1990-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  19. Neuropathological Consequences of Gestational Exposure to Concentrated Ambient Fine and Ultrafine Particles in the Mouse.

    PubMed

    Klocke, Carolyn; Allen, Joshua L; Sobolewski, Marissa; Mayer-Pröschel, Margot; Blum, Jason L; Lauterstein, Dana; Zelikoff, Judith T; Cory-Slechta, Deborah A

    2017-04-01

    Increasing evidence indicates that the central nervous system (CNS) is a target of air pollution. We previously reported that postnatal exposure of mice to concentrated ambient ultrafine particles (UFP; ≤100 nm) via the University of Rochester HUCAPS system during a critical developmental window of CNS development, equivalent to human 3rd trimester, produced male-predominant neuropathological and behavioral characteristics common to multiple neurodevelopmental disorders, including autism spectrum disorder (ASD), in humans. The current study sought to determine whether vulnerability to fine (≤2.5 μm) and UFP air pollution exposure extends to embryonic periods of brain development in mice, equivalent to human 1st and 2nd trimesters. Pregnant mice were exposed 6 h/day from gestational days (GDs) 0.5-16.5 using the New York University VACES system to concentrated ambient fine/ultrafine particles at an average concentration of 92.69 μg/m3 over the course of the exposure period. At postnatal days (PNDs) 11-15, neuropathological consequences were characterized. Gestational air pollution exposures produced ventriculomegaly, increased corpus callosum (CC) area and reduced hippocampal area in both sexes. Both sexes demonstrated CC hypermyelination and increased microglial activation and reduced total CC microglia number. Analyses of iron deposition as a critical component of myelination revealed increased iron deposition in the CC of exposed female offspring, but not in males. These findings demonstrate that vulnerability of the brain to air pollution extends to gestation and produces features of several neurodevelopmental disorders in both sexes. Further, they highlight the importance of the commonalities of components of particulate matter exposures as a source of neurotoxicity and common CNS alterations. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e

  20. Long-range transport episodes of fine particles in southern Finland during 1999-2007

    NASA Astrophysics Data System (ADS)

    Niemi, Jarkko V.; Saarikoski, Sanna; Aurela, Minna; Tervahattu, Heikki; Hillamo, Risto; Westphal, Douglas L.; Aarnio, Päivi; Koskentalo, Tarja; Makkonen, Ulla; Vehkamäki, Hanna; Kulmala, Markku

    The frequency, strength and sources of long-range transport (LRT) episodes of fine particles (PM 2.5) were studied in southern Finland using air quality monitoring results, backward air mass trajectories, remote sensing of fire hot spots, transport and dispersion modelling of smoke and chemical analysis of particle samples (black carbon, monosaccharide anhydrides, oxalate, succinate, malonate, SO 42-, NO 3-, K + and NH 4+). At an urban background site in Helsinki, the daily WHO guideline value (24-h PM 2.5 mean 25 μg m -3) was exceeded during 1-7 LRT episodes per year in 1999-2007. The 24-h mean maximum concentrations varied between 25 and 49 μg m -3 during the episodes, which was 3-6 times higher than the local mean concentration (8.7 μg m -3) in 1999-2007. The highest particle concentrations (max. 1-h mean 163 μg m -3) and the longest episodes (max. 9 days) were mainly caused by the emissions from open biomass burning, especially during springs and late-summers in 2002 and 2006. During the period 2001-2007, the satellite remote sensing of active fire hot spots and transport and dispersion modelling of smoke indicated that approximately half of the episodes were caused partly by the emissions from wildfires and/or agricultural waste burning in fields in Eastern Europe, especially in Russia, Belarus and Ukraine. Other episodes were mainly caused by the LRT of ordinary anthropogenic pollutants, e.g. from energy production, traffic, industry and wood combustion. During those 'other episodes', air masses also arrived from Eastern Europe, including Poland. The highest concentrations of biomass-burning tracers, such as monosaccharide anhydrides (levoglucosan + mannosan + galactosan) and K +, were observed during open biomass-burning episodes, but quite high values were also measured during some winter episodes due to wood combustion emissions. Our results indicate that open biomass burning in Eastern Europe causes high fine particle concentration peaks in large

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

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

  2. Utilization of the Fine Particles Obtained from Cold Pressed Vegetable Oils: A Case Study in Organic Rice Bran, Sunflower and Sesame Oils.

    PubMed

    Srikaeo, Khongsak; Poungsampao, Phuttan; Phuong, Nguyen Thi

    2017-01-01

    Fine particles obtained from the physical refining of organic cold pressed vegetable oils which are normally discarded as a process waste can be utilized as cosmetic and food ingredients. This paper demonstrated the use of the fine particles from rice bran (Thai Jasmine and Riceberry varieties), sunflower and sesame oils as the ingredient in body mask and as dietary fiber. It was found that the fine particles from rice brans exhibited better antioxidant properties than those of sunflower and sesame. The mixed fine particles were added to body mask formula. The addition of the fine particles affected the physical properties and stability of the body mask especially viscosity and pH. Total dietary fiber recovered from the fine particles ranged from 17.91-23.83 g/100g dry sample. Dietary fiber from Riceberry exhibited the best antioxidant properties as evidenced by DPPH radical scavenging activity and reducing power.

  3. Contribution of fine-particle sulfates to light scattering in St. Louis

    SciTech Connect

    Vossler, R.L.

    1985-01-01

    The extent to which sulfates produce visibility reduction in the St. Louis area was examined. The contribution of fine aerosol sulfates to total light scattering was calculated from measured sulfur size distributions and Mie theory of light scattering. The aerosol was collected during both a summer and a winter season. Short sampling intervals (10 minutes to 3 hours) permitted observation of the fine structure of the sulfur size distribution and concentration, and involved only small changes in meteorology. Size separation was accomplished with an 8-stage low pressure impactor, which yielded size fractions in the range of 4 ..mu..m greater than or equal to d greater than or equal to 0.05 ..mu..m. Elemental sulfur was measured by flash volatilization and flame photometric detection. All fine sulfur was assumed to be in the form of (NH/sub 4/)/sub 2/SO/sub 4/. Water which might be associated with this deliquescent aerosol was estimated. The measured light scattering coefficient and (NH/sub 4/)/sub 2/SO/sub 4/ were extremely well correlated (r = 0.97) in the summer, but not as well correlated (r = 0.63) in the winter. Conversely, the light scattering coefficient and non-sulfate fine mass were well correlated (r = 0.85) in the winter, but poorly correlated (r = 0.24) in the summer. The light scattering efficiency of (NH/sub 4/)/sub 2/SO/sub 4/ plus associated water calculated from Mie theory and size distributions was 4.2 m/sup 2//g for the summer aerosol, but only 2.0 m/sup 2//g for the dry winter (NH/sub 4/)/sub 2/SO/sub 4/. Two basic types of sulfur size distributions were observed. The most common type observed during the summer had a major sulfur mass peak between 0.5 ..mu..m and 1.0 ..mu..m in diameter. The combination of large sulfate particles and high sulfate loadings led to the dominance of sulfates in visibility reduction during the summer.

  4. Fine-particle water and pH in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Guo, H.; Xu, L.; Bougiatioti, A.; Cerully, K. M.; Capps, S. L.; Hite, J. R., Jr.; Carlton, A. G.; Lee, S.-H.; Bergin, M. H.; Ng, N. L.; Nenes, A.; Weber, R. J.

    2015-05-01

    Particle water and pH are predicted using meteorological observations (relative humidity (RH), temperature (T)), gas/particle composition, and thermodynamic modeling (ISORROPIA-II). A comprehensive uncertainty analysis is included, and the model is validated. We investigate mass concentrations of particle water and related particle pH for ambient fine-mode aerosols sampled in a relatively remote Alabama forest during the Southern Oxidant and Aerosol Study (SOAS) in summer and at various sites in the southeastern US during different seasons, as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study. Particle water and pH are closely linked; pH is a measure of the particle H+ aqueous concentration and depends on both the presence of ions and amount of particle liquid water. Levels of particle water, in turn, are determined through water uptake by both the ionic species and organic compounds. Thermodynamic calculations based on measured ion concentrations can predict both pH and liquid water but may be biased since contributions of organic species to liquid water are not considered. In this study, contributions of both the inorganic and organic fractions to aerosol liquid water were considered, and predictions were in good agreement with measured liquid water based on differences in ambient and dry light scattering coefficients (prediction vs. measurement: slope = 0.91, intercept = 0.5 μg m-3, R2 = 0.75). ISORROPIA-II predictions were confirmed by good agreement between predicted and measured ammonia concentrations (slope = 1.07, intercept = -0.12 μg m-3, R2 = 0.76). Based on this study, organic species on average contributed 35% to the total water, with a substantially higher contribution (50%) at night. However, not including contributions of organic water had a minor effect on pH (changes pH by 0.15 to 0.23 units), suggesting that predicted pH without consideration of organic water could be sufficient for the purposes of aqueous

  5. Measurement and capture of fine and ultrafine particles from a pilot-scale pulverized coal combustor with an electrostatic precipitator

    SciTech Connect

    Ying Li; Achariya Suriyawong; Michael Daukoru; Ye Zhuang; Pratim Biswas

    2009-05-15

    Experiments were carried out in a pilot-scale pulverized coal combustor at the Energy and Environmental Research Center (EERC) burning a Powder River Basin (PRB) subbituminous coal. A scanning mobility particle sizer (SMPS) and an electrical low-pressure impactor (ELPI) were used to measure the particle size distributions (PSDs) in the range of 17 nm to 10 m at the inlet and outlet of the electrostatic precipitator (ESP). At the ESP inlet, a high number concentration of ultrafine particles was found, with the peak at approximately 75 nm. A trimodal PSD for mass concentration was observed with the modes at approximately 80-100 nm, 1-2 {mu}m, and 10 {mu}m. The penetration of ultrafine particles through the ESP increased dramatically as particle size decreased below 70 nm, attributable to insufficient or partial charging of the ultrafine particles. Injection of nanostructured fine-particle sorbents for capture of toxic metals in the flue gas caused high penetration of the ultrafine particles through the ESP. The conventional ESP was modified to enhance charging using soft X-ray irradiation. A slipstream of flue gas was introduced from the pilot-scale facility and passed through this modified ESP. Enhancement of particle capture was observed with the soft X-ray irradiation when moderate voltages were used in the ESP, indicating more efficient charging of fine particles. 32 refs., 5 figs., 1 tab.

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

    SciTech Connect

    Jost O.L. Wendt

    2003-01-31

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. Previous research results have demonstrated that the inhalation of coal/MSS ash particles cause an increase in lung permeability than coal ash particles alone. Elemental analysis of the coal/MSS ash particles showed that Zn was more abundant in these ash particles than the ash particles of coal ash alone.

  7. Immersion calorimetry of fine coal particles and its relation to flotation

    SciTech Connect

    Melkus, T.G.; Chiang, S.H.; Wen, W.W.

    1987-01-01

    A Setaram C-80 heat flux microcalorimeter was used to study the surface and interfacial properties of fine coal particles in water containing flotation agents via heat of immersion measurements. Heat of immersion (..delta..H/sub imm/) is usually a small exothermic quantity and can be used to characterize a solid in terms of its relative hydrophobicity or hydrophilicity. The effects of coal type, surface oxidation, mineral matter content, kerosene concentration, and pH on the wetting characteristics were investigated. Although coal is a heterogeneous mixture of organic and inorganic materials, immersional calorimetry has proven to be quite helpful in measuring surface properties of coal, and the following conclusions can be drawn: The heat of immersion decreased with increasing kerosene concentration, which corresponds to the coal particles increasing hydrophobicity; in varying the pH, the ..delta..H/sub imm/ went through a minimum at a pH value of 6.5 to 7.0, which coincides with the reported optimum pH range for flotation; both oxidation and clay slime coating (addition of kaolin), which are known to make the coal less hydrophobic, increased the ..delta..H/sub imm/; and the trends that were shown to exist in the heat of immersion measurements (for varying kerosene concentration, pH oxidation, and clay slime coating) correlated well with independent flotation experiments. 16 refs., 6 figs., 2 tabs.

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

    PubMed Central

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

    2017-01-01

    As fine particle (FP) pollution is harmful to humans, previous studies have focused on the mechanisms of FP removal by forests. The current study aims to compare the FP removal capacities of urban forests and wetlands on the leaf, canopy, and landscape scales. Water washing and scanning electron microscopy are used to calculate particle accumulation on leaves, and models are used to estimate vegetation collection, sedimentation, and dry deposition. Results showed that, on the leaf scale, forest species are able to accumulate more FP on their leaf surface than aquatic species in wetlands. On the canopy scale, horizontal vegetation collection is the major process involved in FP removal, and the contribution of vertical sedimentation/emission can be ignored. Coniferous tree species also showed stronger FP collection ability than broadleaf species. In the landscape scale, deposition on the forest occurs to a greater extent than that on wetlands, and dry deposition is the major process of FP removal on rain-free days. In conclusion, when planning an urban green system, planting an urban forest should be the first option for FP mitigation. PMID:28393900

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

  10. Ultra Fine Particles from Diesel Engines Induce Vascular Oxidative Stress via JNK Activation

    PubMed Central

    Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

    2011-01-01

    Exposure of particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultra fine particles (UFP) from diesel vehicle engines have been shown to be pro-atherogenic in apoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induced vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intra-cellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O2·-) production in human aortic endothelial cells (HAEC). Flow cytometry (FACS) showed that UFP increased MitoSOX Red intensity specific for mitochondrial superoxide. Protein carbonyl content is increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated hemeoxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pre-treatment with antioxidant, N-acetyl cysteine (NAC), significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP stimulated O2·- production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation play an important role in UFP-induced oxidative stress and stress response gene expression. PMID:19154785

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

    NASA Astrophysics Data System (ADS)

    See, Siao Wei; Balasubramanian, Rajasekhar

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

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

    PubMed

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

    2006-10-10

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

  13. Comparison of Satellite Observations of Aerosol Optical Depth to Surface Monitor Fine Particle Concentration

    NASA Technical Reports Server (NTRS)

    Kleb, Mary M.; AlSaadi, Jassim A.; Neil, Doreen O.; Pierce, Robert B.; Pippin, Margartet R.; Roell, Marilee M.; Kittaka, Chieko; Szykman, James J.

    2004-01-01

    Under NASA's Earth Science Applications Program, the Infusing satellite Data into Environmental Applications (IDEA) project examined the relationship between satellite observations and surface monitors of air pollutants to facilitate a more capable and integrated observing network. This report provides a comparison of satellite aerosol optical depth to surface monitor fine particle concentration observations for the month of September 2003 at more than 300 individual locations in the continental US. During September 2003, IDEA provided prototype, near real-time data-fusion products to the Environmental Protection Agency (EPA) directed toward improving the accuracy of EPA s next-day Air Quality Index (AQI) forecasts. Researchers from NASA Langley Research Center and EPA used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument combined with EPA ground network data to create a NASA-data-enhanced Forecast Tool. Air quality forecasters used this tool to prepare their forecasts of particle pollution, or particulate matter less than 2.5 microns in diameter (PM2.5), for the next-day AQI. The archived data provide a rich resource for further studies and analysis. The IDEA project uses data sets and models developed for tropospheric chemistry research to assist federal, state, and local agencies in making decisions concerning air quality management to protect public health.

  14. Ventilation dependence of concentration metrics of Ultra-fine Particles in a coagulating household smoke.

    PubMed

    Anand, S; Sreekanth, B; Mayya, Y S

    2016-01-01

    Role of Ultra-fine Particles (UFPs) in causing adverse health effects among large population across the world, attributable to household smoke, is being increasingly recognized. However, there is very little theoretical perspective available on the complex behavior of the UFP metrics with respect to controlling factors, such as ventilation rate and particle emission rate from the combustion sources. This numerical study examines through coagulation dynamics, the dependence of UFP metrics, viz., number (PN), mass (PM(0.1)) and surface area (PA(0.1)) concentrations below 0.1 μm diameter, on ventilation and the number emission rate from household smoke. For strong sources, the steady-state concentrations of these metrics are found to increase initially with increasing Air Exchange Rate (AER), reach a peak value and then decrease. Counter correlations are seen between UFP metric and PM(2.5) concentrations. The concepts of Critical Air Exchange Rate (CAER) and Half-Value Air Exchange Rate (HaVAER) have been introduced which indicate a feasibility of mitigation of PM(0.1) and PA(0.1), unlike PN, by ventilation techniques. The study clearly brings forth complex differential behavior of the three UFP metrics. The results are further discussed.

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

    PubMed

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  17. Cell damage in vitro following direct contact with fine particles of titanium, titanium alloy and cobalt-chrome-molybdenum alloy.

    PubMed

    Evans, E J

    1994-07-01

    Fibroblastic cells in vitro were exposed to powders of titanium, titanium-aluminium-vanadium alloy and cobalt-chrome-molybdenum (Co-Cr-Mo) alloy, either in direct contact with the cells or separated from the cells by a microporous membrane. Fine particles of all the materials reduced cell growth when in direct contact with cells, but only the finest particles of Co-Cr-Mo alloy caused cell damage through the microporous membrane. This provides further evidence that there is a mechanism of cell damage in vitro which depends on a direct interaction between cells and particles and is largely independent of the chemical nature of the particle.

  18. Energy-filtered TEM imaging and EELS study of ODS particles and argon-filled cavities in ferritic-martensitic steels.

    PubMed

    Klimiankou, M; Lindau, R; Möslang, A

    2005-01-01

    Oxide-dispersion-strengthened (ODS) ferritic-martensitic steels with yttrium oxide (Y(2)O(3)) have been produced by mechanical alloying and hot isostatic pressing for use as advanced material in fusion power reactors. Argon gas, usually widely used as inert gas during mechanical alloying, was surprisingly detected in the nanodispersion-strengthened materials. Energy-filtered transmission electron microscopy (EFTEM) and electron energy loss spectroscopy (EELS) led to the following results: (i) chemical composition of ODS particles, (ii) voids with typical diameters of 1-6 nm are formed in the matrix, (iii) these voids are filled with Ar gas, and (iv) the high-density nanosized ODS particles serve as trapping centers for the Ar bubbles. The Ar L(3,2) energy loss edge at 245 eV as well as the absorption features of the ODS particle elements were identified in the EELS spectrum. The energy resolution in the EEL spectrum of about 1.0 eV allows to identify the electronic structure of the ODS particles.

  19. Fine-tuning of process conditions to improve product uniformity of polystyrene particles used for wind tunnel velocimetry

    NASA Technical Reports Server (NTRS)

    Ray, Asit K.

    1990-01-01

    Monodisperse polymer particles (having uniform diameter) were used for the last two decades in physical, biological, and chemical sciences. In NASA Langley Research Center monodisperse polystyrene particles are used in wind tunnel laser velocimeters. These polystyrene (PS) particles in latex form were formulated at the Engineering Laboratory of FENGD using emulsion-free emulsion polymerization. Monodisperse PS latices particles having different particle diameters were formulated and useful experimental data involving effects of process conditions on particle size were accumulated. However, similar process conditions and chemical recipes for polymerization of styrene monomer have often yielded monodisperse particles having varying diameters. The purpose was to improve the PS latex product uniformity by fine-tuning the process parameters based on the knowledge of suspension and emulsion polymerization.

  20. Use of micro-XANES to speciate chromium in airborne fine particles in the Sacramento Valley

    SciTech Connect

    Michelle L. Werner; Peter S. Nico; Matthew A. Marcus; Cort Anastasio

    2007-07-15

    While particulate matter (PM) in the atmosphere can lead to a wide array of negative health effects, the cause of toxicity is largely unknown. One aspect of PM that likely affects health is the chemical composition, in particular the transition metals within the particles. Chromium is one transition metal of interest due to its two major oxidation states, with Cr(III) being much less toxic compared to Cr(VI). Using microfocused X-ray absorption near edge structure (micro-XANES), we analyzed the Cr speciation in fine particles (diameters {le} 2.5 {mu}m) collected at three sites in the Sacramento Valley of northern California: Sacramento, a large urban area, Davis, a small city, and Placerville, a rural area. These are several major stationary sources of Cr within 24 km of the site including chrome-plating plants, power plants and incinerators. The microfocused X-ray beam enables us to look at very small areas on the filter with a resolution of typically 5-7 micrometers. With XANES we are able to not only distinguish between Cr(VI) and Cr(III), but also to identify different types of Cr(III) and more reduced Cr species. At all of our sampling sites the main Cr species were Cr(III), with Cr(OH){sub 3} or a Cr-Fe, chromite-like, phase being the dominant species. Cr(VI)-containing particles were found only in the most urban site. All three sites contained some reduced Cr species, either Cr(0) or Cr{sub 3}C{sub 2}, although these were minor components. This work demonstrates that micro-XANES can be used as a minimally invasive analytical tool to investigate the composition of ambient PM. 32 refs., 6 figs.

  1. Pulmonary bioassay studies with nanoscale and fine-quartz particles in rats: toxicity is not dependent upon particle size but on surface characteristics.

    PubMed

    Warheit, David B; Webb, Thomas R; Colvin, Vicki L; Reed, Kenneth L; Sayes, Christie M

    2007-01-01

    Pulmonary toxicology studies in rats demonstrate that nanoparticles are more toxic than fine-sized particles of similar chemistry. This study, however, provides evidence to contradict this theory. The aims of the study were (1) to compare the toxicity of synthetic 50 nm nanoquartz I particles versus (mined) Min-U-Sil quartz ( approximately 500 nm); the toxicity of synthetic 12 nm nanoquartz II particles versus (mined) Min-U-Sil ( approximately 500 nm) versus (synthetic) fine-quartz particles (300 nm); and (2) to evaluate the surface activities among the samples as they relate to toxicity. Well-characterized samples were tested for surface activity and hemolytic potential. In addition, groups of rats were instilled with either doses of 1 or 5 mg/kg of carbonyl iron (CI) or various alpha-quartz particle types in phosphate-buffered saline solution and subsequently assessed using bronchoalveolar lavage fluid biomarkers, cell proliferation, and histopathological evaluation of lung tissue at 24 h, 1 week, 1 month, and 3 months postexposure. Exposures to the various alpha-quartz particles produced differential degrees of pulmonary inflammation and cytotoxicity, which were not always consistent with particle size but correlated with surface activity, particularly hemolytic potential. Lung tissue evaluations of three of the quartz samples demonstrated "typical" quartz-related effects--dose-dependent lung inflammatory macrophage accumulation responses concomitant with early development of pulmonary fibrosis. The various alpha-quartz-related effects were similar qualitatively but with different potencies. The range of particle-related toxicities and histopathological effects in descending order were nanoscale quartz II = Min-U-Sil quartz > fine quartz > nanoscale quartz I > CI particles. The results demonstrate that the pulmonary toxicities of alpha-quartz particles appear to correlate better with surface activity than particle size and surface area.

  2. Ion composition of coarse and fine particles in Iasi, north-eastern Romania: Implications for aerosols chemistry in the area

    NASA Astrophysics Data System (ADS)

    Arsene, Cecilia; Olariu, Romeo Iulian; Zarmpas, Pavlos; Kanakidou, Maria; Mihalopoulos, Nikolaos

    2011-02-01

    Atmospheric loadings of the aerosols coarse (particles of AED > 1.5 μm) and fine fractions (particles of AED < 1.5 μm) were determined in Iasi, north-eastern Romania from January 2007 to March 2008. Concentrations of water soluble ions (SO 42-, NO 3-, Cl -, C 2O 42-, NH 4+, K +, Na +, Ca 2+ and Mg 2+) were measured using ion chromatography (IC). In the coarse particles, calcium and carbonate are the main ionic constituents (˜65%), whereas in the fine particles SO 42-, NO 3-, Cl - and NH 4+ are the most abundant. Temperature and relative humidity (RH) associated with increased concentrations of specific ions might be the main factors controlling the aerosol chemistry at the investigated site. From August 2007 to March 2008 high RH (as high as 80% for about 82% of the investigated period) was prevailing in Iasi and the collected particles were expected to have deliquesced and form an internal mixture. We found that in fine particles ammonium nitrate (NH 4NO 3) is important especially under conditions of NH 4+/SO 42- ratio higher than 1.5 and high RH (RH above deliquescence of NH 4Cl, NH 4NO 3 and (NH 4) 2SO 4). At the investigated site large ammonium artifacts may occur due to inter-particle interaction especially under favorable meteorological conditions. A methodology for estimating the artifact free ambient ammonium concentration is proposed for filter pack sampling data of deliquesced particles. Nitrate and sulfate ions in coarse particles are probably formed via reactions of nitric and sulfuric acid with calcium carbonate and sodium chloride which during specific seasons are abundant at the investigated site. In the fine mode sulfate concentration maximized during summer (due to enhanced photochemistry) and winter (due to high concentration of SO 2 emitted from coal burning). Natural contributions, dust or sea-salt related, prevail mainly in the coarse particles. From May 2007 to August 2007, when air masses originated mainly from Black Sea, in the coarse

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

    PubMed

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

    2013-12-17

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

  4. [Concentrations of fine particulate matters and ultrafine particles and influenced factors during winter in an area of Beijing].

    PubMed

    Ni, Yang; Tu, Xing-ying; Zhu, Yi-dan; Guo, Xin-biao; Deng, Fu-rong

    2014-06-18

    To study the concentrations of fine particulate matters and ultrafine particles and influenced factors during winter in an area of Beijing. Real-time monitoring of particles' mass and number concentrations were conducted in an area of Beijing from February 7(th) to 27(th), 2013. At the same time, the meteorological data were also collected from the Beijing meteorological website. Differences of the particles' mass and number concentrations during different periods were analyzed using Mann-Whitney U test. Meanwhile, the influenced factors were also analyzed. The mean concentrations of fine particulate matters and ultrafine particles were (157.2 ± 142.8) μg/m³ and (25 018 ± 9 309) particles/cm³, respectively. The particles' number and mass concentrations in haze days were 1.27 times and 2.91 times higher than those in non-haze days, respectively. The mass concentrations of fine particulate matters in the self-monitoring site were higher than those in the nearest central monitoring sites, and the hourly-average concentrations of particles were significantly consistent with those at the commuter times. Meanwhile, the setting off of fireworks/firecrackers during the Spring Festival could lead to short-term increases of the particles' number and mass concentrations. When the wind speed was low and the related humidity was high, the concentrations of particulate matters were relatively high, and the mass concentrations of fine particulate matters were lagged about 1-2 d. The level of the particulate matters in this area was high. Heavy traffic, setting off of fireworks/firecrackers and meteorological factors may be some of the main factors affecting the concentrations of the particulate matters in this area. Among those factors, the effect of setting off of fireworks/firecrackers didn't last long and the effect of the meteorological factors had a hysteresis effect.

  5. Synthesis of Novel Ferrite Based Recyclable Catalyst Used to Clean Dye and Emerging Contaminates from Water

    EPA Science Inventory

    Herein, we describe synthesis of novel palladium, copper, cobalt and vanadium ferrites. The ferrites were synthesized by combustion method using polyvinyl alcohol. The particles phases were confirmed using X-ray diffraction and sizes were determined using particle size analyzer. ...

  6. Synthesis of Novel Ferrite Based Recyclable Catalyst Used to Clean Dye and Emerging Contaminates from Water

    EPA Science Inventory

    Herein, we describe synthesis of novel palladium, copper, cobalt and vanadium ferrites. The ferrites were synthesized by combustion method using polyvinyl alcohol. The particles phases were confirmed using X-ray diffraction and sizes were determined using particle size analyzer. ...

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

    PubMed

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

    2017-01-12

    To analyze the association between fine particulate matter concentration in the atmosphere and hospital care by acute respiratory diseases in children. Ecological study, carried out in the region of Grande Vitória, Espírito Santo, in the winter (June 21 to September 21, 2013) and summer (December 21, 2013 to March 19, 2014). We assessed data of daily count for outpatient care and hospitalization by respiratory diseases (ICD-10) in children from zero to 12 years in three hospitals in the Region of Grande Vitória. For collecting fine particulate matter, we used portable samplers of particles installed in six locations in the studied region. The Generalized Additive Model with Poisson distribution, fitted for the effects of predictor covariates, was used to evaluate the relationship between respiratory outcomes and concentration of fine particulate matter. The increase of 4.2 µg/m3 (interquartile range) in the concentration of fine particulate matter increased in 3.8% and 5.6% the risk of medical care or hospitalization, respectively, on the same day and with six-day lag from the exposure. We identified positive association between outpatient care and hospitalizations of children under 12 years due to acute respiratory diseases and the concentration of fine particulate matter in the atmosphere. Analisar a associação entre a concentração de material particulado fino na atmosfera e atendimento hospitalar por doenças respiratórias agudas em crianças. Estudo ecológico, realizado na Região da Grande Vitória, ES, no inverno (21 de junho a 21 de setembro de 2013) e no verão (21 de dezembro de 2013 a 19 de março de 2014). Foram avaliados dados de contagem diária de atendimentos ambulatoriais e hospitalizações por doenças respiratórias (CID-10) em crianças de zero a 12 anos em três hospitais da Região da Grande Vitoria. Para a coleta de material particulado fino foram utilizados amostradores portáteis de partículas instalados em seis locais na regi

  8. High retention of N P nutrients, soil organic carbon, and fine particles by cover crops under tropical climate

    USDA-ARS?s Scientific Manuscript database

    Conservation of soil and water is fundamental to the development of sustainable agriculture. Transport of nitrogen (N) and phosphorus (P), and fine soil particles down the soil profile of a gravelly loam soil (loamy-skeletal, carbonatic, hyperthermic Lithic Udorthents) was investigated under various...

  9. Pulmonary effects of inhaled concentrated fine particles (PM2.5) in somkers and patients with chronic obstructive lung disease

    EPA Science Inventory

    Although numerous field and epidemiological studies of particulate matter (PM) have strongly suggested that patients with COPD and smokers may be susceptible to fine particles (PM2.5), very little is known about the health effects on such sub-populations. In a randomized double...

  10. Pulmonary effects of inhaled concentrated fine particles (PM2.5) in somkers and patients with chronic obstructive lung disease

    EPA Science Inventory

    Although numerous field and epidemiological studies of particulate matter (PM) have strongly suggested that patients with COPD and smokers may be susceptible to fine particles (PM2.5), very little is known about the health effects on such sub-populations. In a randomized double...

  11. CONTINUOUS MONITORING OF ULTRAFINE, FINE, AND COARSE PARTICLES IN A RESIDENCE FOR 18 MONTHS IN 1999-2000

    EPA Science Inventory

    Continuous monitors were employed for 18 months in an occupied townhouse to measure ultrafine, fine, and coarse particles; air change rates; wind speed and direction; temperature; and relative humidity (RH). A main objective was to document short-term and long-term variation in...

  12. CONTINUOUS MONITORING OF ULTRAFINE, FINE, AND COARSE PARTICLES IN A RESIDENCE FOR 18 MONTHS IN 1999-2000

    EPA Science Inventory

    Continuous monitors were employed for 18 months in an occupied townhouse to measure ultrafine, fine, and coarse particles; air change rates; wind speed and direction; temperature; and relative humidity (RH). A main objective was to document short-term and long-term variation in...

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  15. Neurodevelopmental Deceleration by Urban Fine Particles from Different Emission Sources: A Longitudinal Observational Study

    PubMed Central

    Basagaña, Xavier; Esnaola, Mikel; Rivas, Ioar; Amato, Fulvio; Alvarez-Pedrerol, Mar; Forns, Joan; López-Vicente, Mònica; Pujol, Jesús; Nieuwenhuijsen, Mark; Querol, Xavier; Sunyer, Jordi

    2016-01-01

    Background: A few studies have reported associations between traffic-related air pollution exposure at schools and cognitive development. The role of PM components or sources other than traffic on cognitive development has been little explored. Objectives: We aimed to explore the role of PM sources in school air on cognitive development. Methods: A cohort of 2,618 schoolchildren (average age, 8.5 years) belonging to 39 schools in Barcelona (Spain) was followed up for a year. Children completed computerized tests assessing working memory, superior working memory, and inattentiveness during four visits. Particulate matter ≤ 2.5 μm (PM2.5) was measured during two 1-week campaigns in each school, both outdoors and in the classroom. Source apportionment resulted in nine sources: mineral, organic/textile/chalk, traffic, secondary sulfate and organics, secondary nitrate, road dust, metallurgy, sea spray, and heavy oil combustion. Differences in cognitive growth trajectories were assessed with mixed models with age-by-source interaction terms. Results: An interquartile range increase in indoor traffic-related PM2.5 was associated with reductions in cognitive growth equivalent to 22% (95% CI: 2%, 42%) of the annual change in working memory, 30% (95% CI: 6%, 54%) of the annual change in superior working memory, and 11% (95% CI: 0%, 22%) of the annual change in the inattentiveness scale. None of the other PM2.5 sources was associated with adverse effects on cognitive development. Conclusions: Traffic was the only source of fine particles associated with a reduction in cognitive development. Reducing air pollution from traffic at primary schools may result in beneficial effects on cognition. Citation: Basagaña X, Esnaola M, Rivas I, Amato F, Alvarez-Pedrerol M, Forns J, López-Vicente M, Pujol J, Nieuwenhuijsen M, Querol X, Sunyer J. 2016. Neurodevelopmental deceleration by urban fine particles from different emission sources: a longitudinal observational study. Environ

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

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

  17. Inviscid behaviour of fines-rich pyroclastic flows inferred from experiments on gas-particle mixtures [rapid communication

    NASA Astrophysics Data System (ADS)

    Roche, O.; Gilbertson, M. A.; Phillips, J. C.; Sparks, R. S. J.

    2005-12-01

    Experiments were carried out on granular flows generated by instantaneous release of gas-fluidised, bidisperse mixtures and propagating into a horizontal channel. The mixture consists of fine (< 100 μm) and coarse (> 100 μm) particles of same density, with corresponding grain size ratios of ˜ 2 to 9. Initial fluidisation of the mixture destroys the interparticle frictional contacts, and the flow behaviour then depends on the initial bed packing and on the timescale required to re-establish strong frictional contacts. At a fines mass fraction ( α) below that of optimal packing (˜ 40%), the initial mixtures consist of a continuous network of coarse particles with fines in interstitial voids. Strong frictional contacts between the coarse particles are probably rapidly re-established and the flows steadily decelerate. Some internal friction reduction appears to occur as α and the grain size ratio increases, possibly due to particle rolling and the lower roughness of internal shear surfaces. Segregation only occurs at large grain size ratio due to dynamical sieving with fines concentrated at the flow base. In contrast, at α above that for optimal packing, the initial mixtures consist of coarse particles embedded in a matrix of fines. Flow velocities and run-outs are similar to that of the monodisperse fine end-member, thus showing that the coarse particles are transported passively within the matrix whatever their amount and grain size are. These flows propagate at constant height and velocity as inviscid fluid gravity currents, thus suggesting negligible interparticle friction. We have determined a Froude number of 2.61 ± 0.08 consistent with the dam-break model for fluid flows, and with no significant variation as a function of α, the grain size ratio, and the initial bed expansion. Very little segregation occurs, which suggests low intensity particle interactions during flow propagation and that active fluidisation is not taking place. Strong frictional

  18. Structural and magnetic properties of nickel-zinc ferrite nanocrystalline magnetic particles prepared by microwave combustion method

    NASA Astrophysics Data System (ADS)

    Parmar, H.; Upadhyay, R. V.; Rayaprol, S.; Siruguri, V.

    2014-12-01

    Magnetic, nano-crystalline samples of zinc substituted nickel ferrite, (ZnxNi1-xFe2O4 for x = 0.0-0.9 in step of 0.2), are synthesized using microwave combustion synthesis technique. The structural properties of Ni-Zn are determined using X-ray powder diffraction, transmission electron microscopy; Fourier transforms infrared spectroscopy and neutron diffraction techniques. Average crystalline size obtained from X-ray diffraction and neutron diffraction is in the range of 30-60 nm. The cation distribution obtained from X-ray diffraction and neutron diffraction show that Zn occupies only tetrahedral A-site in the spinel lattice. The values of magnetic moment derived from magnetization measurements and neutron diffraction agrees nearly 97 % to that of bulk at 300 K. This methodology can be used to prepare large quantities (about 10 g) of sample at one time using kitchen microwave oven working at 1,200 W power.

  19. Increase in relative deposition of fine particles in the rat lung periphery in the absence of gravity.

    PubMed

    Darquenne, Chantal; Borja, Maria G; Oakes, Jessica M; Breen, Ellen C; Olfert, I Mark; Scadeng, Miriam; Prisk, G Kim

    2014-10-15

    While it is well recognized that pulmonary deposition of inhaled particles is lowered in microgravity (μG) compared with gravity on the ground (1G), the absence of sedimentation causes fine particles to penetrate deeper in the lung in μG. Using quantitative magnetic resonance imaging (MRI), we determined the effect of gravity on peripheral deposition (DEPperipheral) of fine particles. Aerosolized 0.95-μm-diameter ferric oxide particles were delivered to spontaneously breathing rats placed in plethysmographic chambers both in μG aboard the NASA Microgravity Research Aircraft and at 1G. Following exposure, lungs were perfusion fixed, fluid filled, and imaged in a 3T MR scanner. The MR signal decay rate, R2*, was measured in each voxel of the left lung from which particle deposition (DEP) was determined based on a calibration curve. Regional deposition was assessed by comparing DEP between the outer (DEPperipheral) and inner (DEPcentral) areas on each slice, and expressed as the central-to-peripheral ratio. Total lung deposition tended to be lower in μG compared with 1G (1.01 ± 0.52 vs. 1.43 ± 0.52 μg/ml, P = 0.1). In μG, DEPperipheral was larger than DEPcentral (P < 0.03), while, in 1G, DEPperipheral was not significantly different from DEPcentral. Finally, central-to-peripheral ratio was significantly less in μG than in 1G (P ≤ 0.05). These data show a larger fraction of fine particles depositing peripherally in μG than in 1G, likely beyond the large- and medium-sized airways. Although not measured, the difference in the spatial distribution of deposited particles between μG and 1G could also affect particle retention rates, with an increase in retention for particles deposited more peripherally.

  20. Increase in relative deposition of fine particles in the rat lung periphery in the absence of gravity

    PubMed Central

    Borja, Maria G.; Oakes, Jessica M.; Breen, Ellen C.; Olfert, I. Mark; Scadeng, Miriam; Prisk, G. Kim

    2014-01-01

    While it is well recognized that pulmonary deposition of inhaled particles is lowered in microgravity (μG) compared with gravity on the ground (1G), the absence of sedimentation causes fine particles to penetrate deeper in the lung in μG. Using quantitative magnetic resonance imaging (MRI), we determined the effect of gravity on peripheral deposition (DEPperipheral) of fine particles. Aerosolized 0.95-μm-diameter ferric oxide particles were delivered to spontaneously breathing rats placed in plethysmographic chambers both in μG aboard the NASA Microgravity Research Aircraft and at 1G. Following exposure, lungs were perfusion fixed, fluid filled, and imaged in a 3T MR scanner. The MR signal decay rate, R2*, was measured in each voxel of the left lung from which particle deposition (DEP) was determined based on a calibration curve. Regional deposition was assessed by comparing DEP between the outer (DEPperipheral) and inner (DEPcentral) areas on each slice, and expressed as the central-to-peripheral ratio. Total lung deposition tended to be lower in μG compared with 1G (1.01 ± 0.52 vs. 1.43 ± 0.52 μg/ml, P = 0.1). In μG, DEPperipheral was larger than DEPcentral (P < 0.03), while, in 1G, DEPperipheral was not significantly different from DEPcentral. Finally, central-to-peripheral ratio was significantly less in μG than in 1G (P ≤ 0.05). These data show a larger fraction of fine particles depositing peripherally in μG than in 1G, likely beyond the large- and medium-sized airways. Although not measured, the difference in the spatial distribution of deposited particles between μG and 1G could also affect particle retention rates, with an increase in retention for particles deposited more peripherally. PMID:25170069

  1. Sources of personal exposure to fine particles in Toronto, Ontario, Canada

    SciTech Connect

    David Kim; Andrea Sass-Kortsak; James T. Purdham; Robert E. Dales; Jeffrey R. Brook

    2005-08-01

    Individuals are exposed to particulate matter from both indoor and outdoor sources. The aim of this study was to compare the relative contributions of three sources of personal exposure to fine particles (PM2.5) by using chemical tracers. The study design incorporated repeated 24-hr personal exposure measurements of air pollution from 28 cardiac-compromised residents of Toronto, Ontario, Canada. Each study participant wore the Rupprecht & Patashnick ChemPass Personal Sampling System 1 day a week for a maximum of 10 weeks. During their individual exposure measurement days the subjects reported to have spent an average of 89% of their time indoors. Particle phase elemental carbon, sulfate, and calcium personal exposure data were used in a mixed-effects model as tracers for outdoor PM2.5 from traffic-related combustion, regional, and local crustal materials, respectively. These three sources were found to contribute 13% {+-} 10%, 17% {+-}16%, and 7% {+-} 6% of PM2.5 exposures. The remaining fraction of the personal PM2.5 is hypothesized to be predominantly related to indoor sources. For comparison, central site outdoor PM2.5 measurements for the same dates as personal measurements were used to construct a receptor model using the same three tracers. In this case, traffic-related combustion, regional, and local crustal materials were found to contribute 19% {+-} 17%, 52% {+-} 22%, and 10% {+-} 7%, respectively. The results indicate that the three outdoor PM2.5 sources considered are statistically significant contributors to personal exposure to PM2.5. The results also suggest that among the Toronto subjects, who spent a considerable amount of time indoors, exposure to outdoor PM2.5 includes a greater relative contribution from combustion sources compared with outdoor PM2.5 measurements where regional sources are the dominant contributor. 56 refs., 3 figs., 6 tabs.

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

    PubMed

    Lanzinger, Stefanie; Schneider, Alexandra; Breitner, Susanne; Stafoggia, Massimo; Erzen, Ivan; Dostal, Miroslav; Pastorkova, Anna; Bastian, Susanne; Cyrys, Josef; Zscheppang, Anja; Kolodnitska, Tetiana; Peters, Annette

    2016-11-15

    Evidence of short-term effects of ultrafine particles (UFP) on health is still inconsistent and few multicenter studies have been conducted so far especially in Europe. Within the UFIREG project, we investigated the short-term effects of UFP and fine particulate matter (particulate matter with an aerodynamic diameter less than 2.5 μm [PM2.5]) on daily cause-specific hospital admissions in five Central and Eastern European cities using harmonized protocols for measurements and analyses. Daily counts of cause-specific hospital admissions focusing on cardiovascular and respiratory diseases were obtained for Augsburg and Dresden (Germany), 2011-2012; Chernivtsi (Ukraine), 2013 to March 2014; and Ljubljana (Slovenia) and Prague (Czech Republic), 2012-2013. Air pollution and meteorologic data were measured at fixed monitoring sites in all cities. We analyzed city-specific associations using confounder-adjusted Poisson regression models and pooled the city-specific effect estimates using metaanalysis methods. A 2,750 particles/cm(3) increase (average interquartile range across all cities) in the 6-day average of UFP indicated a delayed and prolonged increase in the pooled relative risk of respiratory hospital admissions (3.4% [95% confidence interval, -1.7 to 8.8%]). We also found increases in the pooled relative risk of cardiovascular (exposure average of lag 2-5, 1.8% [0.1-3.4%]) and respiratory (6-d average exposure, 7.5% [4.9-10.2%]) admissions per 12.4 μg/m(3) increase (average interquartile range) in PM2.5. Our findings indicated delayed and prolonged effects of UFP exposure on respiratory hospital admissions in Central and Eastern Europe. Cardiovascular and respiratory hospital admissions increased in association with an increase in PM2.5. Further multicenter studies are needed using harmonized UFP measurements to draw definite conclusions on health effects of UFP.

  3. Factors affecting the stability of the performance of ambient fine-particle concentrators.

    PubMed

    Kim, S; Sioutas, C; Chang, M C; Gong, H

    2000-01-01

    This article describes a systematic evaluation of factors affecting the stability of the performance of Harvard ambient fine-particle concentrators, an essential requirement for controlled animal and human exposure studies that utilize these technologies. Phenomenological problems during the operation of the concentrator, including pressure drop increase and decrease in concentration enrichment, were statistically correlated with ambient air parameters such as temperature, relative humidity, PM2.5 mass concentration, and mass median diameter. The normalized hourly pressure drop across the concentrator was strongly associated (R2 = .81) with the product of ambient PM2.5 mass concentration and the difference between the vapor pressure downstream of the impactor nozzle and the saturation vapor pressure at the adiabatic expansion temperature (i.e., the temperature of the aerosol immediately downstream of the virtual impactors). From multiple regression analysis, the average enrichment factor was predicted reasonably well (R2 = .67) by aerosol mass median diameter and the normalized hourly pressure drop. Based on these results, we can anticipate in any given day whether an exposure study can be conducted without a considerable increase in the concentrator pressure drop, which might lead to an abrupt or premature termination of the exposure. As particle mass concentration and ambient dewpoint are the two main parameters responsible for raising the pressure drop across the concentrator, efforts should be made to either desiccate the ambient aerosol at days of high dewpoints, or to dilute the ambient PM at days of high concentrations, prior to drawing the aerosol through the virtual impactors. The latter approach is recommended on days of severe ambient pollution conditions because it is simpler and also makes it possible to maintain the appropriate concentration level delivered to the exposure chamber.

  4. Source apportionment of size segregated fine/ultrafine particle by PMF in Beijing

    NASA Astrophysics Data System (ADS)

    Tan, Ji-hua; Duan, Jing-chun; Chai, Fa-he; He, Ke-bin; Hao, Ji-Ming

    2014-03-01

    Considering the adverse health effects to human body, the number concentration of atmospheric PM (particulate material) is more important than the mass concentration. CO, NO, NO2, SO2 and number concentrations of PM were obtained from a remote site (Miyun), a roadside site (North Fourth Ring Road) and an urban residential site (Tsinghua University) in Beijing in winter. The size distribution and the possible sources of number concentrations were examined using EPA PMF (positive matrix factorization) model. A data set of totally 9610 of number concentration with the size range of 0.028 μm to 0.948 μm was included in the PMF analysis. The highest total particle number, mass and area of fine particles concentrations were observed at the North Fourth Ring Road site and the lowest were observed at Miyun site. Four factors were identified at Miyun site, as Factor 1 and Factor 4 may be related to long distance transportation, and Factor 2 and Factor 3 may be assigned as coal combustion and locomotive emission nearby, respectively; three factors were identified at North Fourth Ring Road, of which Factor 1 and Factor 3 are traffic related and Factor 2 may be coal combustion related. Compared with Factor 1, the contributions of Factor 3 to NOx and SO2 were 4-5 times higher. Additionally, Factor 3 was also a major contributor to CO. It suggested that Factor 1 and Factor 3 had the same source emission of motor vehicle, but different engine types, fuel types or exhaust treatments. Three factors were identified at Tsinghua site, as Factor 1 may come from aging vehicle emission, and Factor 2 and Factor 3 may be coal combustion related.

  5. Trends in elemental concentrations of fine particles at remote sites in the United States of America

    NASA Astrophysics Data System (ADS)

    Eldred, Robert A.; Cahill, Thomas A.

    The University of California at Davis has been monitoring particulate concentrations in remote sites throughout the United States of America since 1979 in networks operated for the National Park Service and the Environmental Protection Agency. Twelve sites in remote class I visibility areas have almost complete records from June 1982 to August 1992, seven in the southwest, three in the northwest, and two in the east. During this period, two samples of fine particles (0-2.5 μm) on Teflon filters were collected every week and analysed for elemental concentration by Particle Induced X-ray Emission (PIXE). This paper will examine the historical trends for sulfur, zinc, lead, and the soil elements. Measurements during the past four years have verified that the sulfur is present as sulfate. In the southwest, 80% of the sulfur trends in spring, summer and fall decreased, while most of the winter trends increased. The annual trends decreased at six of the seven sites. The trends in the northwest increased slightly. The two eastern sites had the most important trends, with significant increases of almost 4% per year in summer, 1-3% increases in spring and fall, and 2% decreases in winter. The annual increases were between 2 and 3%. Generally there were no significant trends for zinc and the soil elements. Lead at all sites decreased sharply through 1986, corresponding to the shift to unleaded gasoline, but has since leveled off at around 18% of the 1982 means. The most important conclusion of this study is that through the use of stable sampling and analytical protocols, we have been able to determine statistically significant historical trends of as small as 1-2% per year for sites with 10-year records.

  6. Physicochemical properties and ability to generate free radicals of ambient coarse, fine, and ultrafine particles in the atmosphere of Xuanwei, China, an area of high lung cancer incidence

    NASA Astrophysics Data System (ADS)

    Lu, Senlin; Yi, Fei; Hao, Xiaojie; Yu, Shang; Ren, Jingjing; Wu, Minghong; Jialiang, Feng; Yonemochi, Shinich; Wang, Qingyue

    2014-11-01

    The link between the high incidence of lung cancer and harmful pollutants emitted by local coal combustion in Xuanwei, Yunnan province, China, has been a focus of study since the 1980s. However, the mechanisms responsible for the high lung cancer rate remain unclear, necessitating further study. Since a close relationship between ambient air particle pollution and respiratory diseases exists, we sampled size-resolved ambient particles from the atmosphere of Xuanwei. In our indoor experiment, cutting-edge methods, including scanning electron microscopy coupled with energy dispersive X-ray detection (SEM/EDX), particle-induced X-ray emission (PIXE), electronic paramagnetic resonance (EPR) and the cell-free DCFH-DA assay, were employed to investigate the physicochemical properties, the potential to generate free radicals and the oxidative potential of ambient coarse (diameter, 1.8-10 μm), fine (diameter, 0.1-1.8 μm), and ultrafine (diameter, <0.1 μm) particles. We found the total mass concentrations of the size-resolved particles collected in spring were higher than that in early winter. Mass percentage of fine particles accounted for 68% and 61% of the total particulate mass in spring and in early winter samples, respectively, indicating that fine particles were the major component of the Xuanwei ambient particulate matters. On the other hand, the results of SEM/EDX analysis showed that the coarse particles were dominated by minerals, the fine particles by soot aggregates and fly ashes, and the ultrafine particles by soot particles and unidentified particles. Our PIXE results revealed that crustal elements (Ca, Ti Si, Fe) were mainly distributed in coarse particles, while trace metals (Cr, Mn, Ni, Cu, Zn, Pb) dominated in the fine particle fraction, and S, a typical element emitted by coal combustion, mainly resided in fine particles collected from the winter atmosphere. EPR results indicated that the magnitude of free radical intensity caused by size

  7. Role of mode of heating on the synthesis of nanocrystalline zinc ferrite

    NASA Astrophysics Data System (ADS)

    Chaudhari, Prashant R.; Gaikwad, V. M.; Acharya, S. A.

    2015-08-01

    In the present work, microwave-assisted coprecipitation route was used for synthesis of nanocrystalline zinc ferrite and results were compared with conventionally prepared zinc ferrite. Synthesis conditions were kept uniform in both cases, except that the mode of heating was changed. The effects of mode of heating on the material properties were studied systematically. Microstructures of both samples were studied by scanning electron microscopy and transmission electron microscopy and the particle size was found to be in the range of 3-4 nm. Particle size distribution in microwave-processed MS-ZnFe2O4 is found to be highly uniform compared to conventionally processed samples (CS-ZnFe2O4). XRD data confirmed the presence of single-phase face-centered cubic structure for both the samples. The XRD data fitted well with Reitveld refinement. The functional groups were analyzed by FT-IR. Local distortions in the structures were studied by FT-Raman spectra of zinc ferrites at room temperature. This study concludes that the microwave-assisted synthesis route reduced the time of reaction by around 23 h and developed uniformly distributed fine-scaled particles. This method has high potential to synthesize other ferrite materials also.

  8. Traveling electric field probed by a fine particle above voltage-modulated strips in a striped electrode device

    SciTech Connect

    Li Yangfang; Jiang Ke; Thomas, H. M.; Morfill, G. E.; Zhang Wengui; Ma, J. X.

    2010-03-15

    It is described that the distribution of the horizontal electric field above a striped electrode can be inferred from the trajectory of a single fine particle with known mass and diameter. The striped electrode consists of 100 segmented stainless steel strips, each electrically insulated. A traveling periodic potential profile is produced above the striped electrode by modulating the voltage signals on the strips. When the voltage modulation is on, the fine particle, which is originally levitated in the sheath region above the striped electrode, experiences a periodic oscillation along both the vertical and the horizontal directions because of the periodic electric force arising from the modulation voltages. Tracking the motion of the fine particles, the electric force is obtained from the momentum equation including the gravity and the neutral gas friction. With the particle charge estimated by the vertical oscillation method, the electric field can be derived. The horizontal electric field obtained by this method is in agreement with the result predicted by a collisional particle-in-cell simulation.

  9. Dynamics of fine particles and photo-oxidants in the Eastern Mediterranean (SUB-AERO)

    NASA Astrophysics Data System (ADS)

    Lazaridis, M.; Eleftheriadis, K.; Smolik, J.; Colbeck, I.; Kallos, G.; Drossinos, Y.; Zdimal, V.; Vecera, Z.; Mihalopoulos, N.; Mikuska, P.; Bryant, C.; Housiadas, C.; Spyridaki, A.; Astitha, Marina; Havranek, V.

    As part of the European project SUB-AERO, comprehensive aerosol and gaseous pollutant measurement campaigns were performed at the Finokalia station (July 2000 and January 2001) on the island of Crete (Greece) in combination with boat measurements in the eastern part of the Mediterranean area. The measurements were performed with the participation of nine European research institutions. The objective of the measurement campaigns was to evaluate and assess the spatial and temporal variability of photochemical pollutants and fine particles. The current overview paper presents the framework and main results of the measurements and modelling studies performed during the project. Extensive measurements of gaseous and atmospheric-aerosol physical, chemical and optical characteristics were performed during the measurement campaigns in conjunction with detailed chemical analyses of the aerosol species. Along with the experimental work mesoscale modelling, using a combination of the UAM-AERO air quality model together with the RAMS prognostic meteorological model, was used to reveal the dynamics of particulate matter and photo-oxidants. Furthermore, regional chemistry transport models were applied to determine the background and initial conditions for the mesoscale modelling.

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

    PubMed

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

    2000-04-01

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

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

    PubMed

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

    2017-01-01

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

  12. Electreted polyetherimide-silica fibrous membranes for enhanced filtration of fine particles.

    PubMed

    Li, Xiaoqi; Wang, Na; Fan, Gang; Yu, Jianyong; Gao, Jing; Sun, Gang; Ding, Bin

    2015-02-01

    Development of technologies for air filtration and purification is critical to meet the global challenges of threatened human health and accelerated greenhouse effect, especially for point-of-use applications. Here, we report a novel electreted polyetherimide-silica (PEI-SiO2) fibrous membrane by a single-step strategy to achieve effective filtration of fine particles. The hierarchical structured PEI-SiO2 membranes were endowed with promising superhydrophobicity with a water contact angle of 152°, allowing their better self-cleaning performance compared with commercial polypropylene (PP) filter media. Morphology, electric charge property, porous structure, and filtration performance could be regulated by tuning the type and concentration of electrets as well as the solution properties. Furthermore, unlike the commercial PP-based filter media, the as-prepared membranes can be treated at 200°C for 30min without sacrificing filtration efficiency (99.992%) and pressure drop (61Pa) owing to the combined contribution of polarization and space charges. We anticipate that this promising electreted fibrous medium will act as a core part of numerous air filtration systems, including ultra-low penetration air filters, clean room, respirator, and protective clothing. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

  14. Assessment of inter-individual, geographic, and seasonal variability in estimated human exposure to fine particles.

    PubMed

    Jiao, Wan; Frey, H Christopher; Cao, Ye

    2012-11-20

    Health effects associated with ambient fine particle (PM(2.5)) exposure are typically estimated based on concentration-response (C-R) functions using area-wide concentration as an exposure surrogate. Persons 65 and older are particularly susceptible to adverse effects from PM(2.5) exposure. Using a stochastic microenvironmental simulation model, distributions of daily PM(2.5) exposures were estimated based on ambient concentration, air exchange rate, penetration factor, deposition rate, indoor emission sources, census data, and activity diary data, and compared for selected regions and seasons. Even though the selected subpopulation spends an average of over 20 h per day indoors, the ratio of daily average estimated exposure to ambient concentration (E(a)/C) is approximately 0.5. The daily average E(a)/C ratio varies by a factor of 4-5 over a 95% frequency range among individuals, primarily from variability in air exchange rates. The mean E(a)/C varies by 6-36% among selected NC, TX, and NYC domains, and 15-34% among four seasons, as a result of regional differences in housing stock and seasonal differences in air exchange rates. Variability in E(a)/C is a key factor that may help explain heterogeneity in C-R functions across cities and seasons. Priorities for improving exposure estimates are discussed.

  15. Evaluation of fine-particle size catalysts using standard test procedures

    SciTech Connect

    Stohl, F.V.; Diegert, K.V.; Goodnow, D.C.

    1996-07-01

    The goal of this project is to evaluate and compare the activities/selectivities of fine-particle size catalysts being developed in the DOE/PETC Advanced Research (AR) Liquefaction Program by using standard coal liquefaction activity test procedures. Since bituminous and subbituminous coals have significantly different properties, it is feasible that catalysts may perform differently with these coal types. Because all previous testing has been done with the DECS-17 Blind Canyon bituminous coal, it is important to develop the capability of evaluating catalysts using a subbituminous coal. Initial efforts towards developing a subbituminous coal test are aimed at comparing the reactivities of the Wyodak subbituminous coal and the Blind Canyon bituminous coal. Therefore, the same factorial experimental design was used with the Wyodak coal as was used previously with the Blind Canyon coal. In addition, PNL`s 6-line ferrihydrite catalyst precursor was used in the development of the Wyodak coal test procedure because this catalyst is the best powder catalyst found to date in Sandia`s tests with Blind Canyon coal. Results show that Blind Canyon coal yields higher DHP amounts in the reaction products and higher tetrahydrofuran conversions at the higher severity conditions. Wyodak coal gives higher heptane conversions and higher gas yields for all conditions tested.

  16. Fine particle pH during severe haze episodes in northern China

    NASA Astrophysics Data System (ADS)

    Liu, Mingxu; Song, Yu; Zhou, Tian; Xu, Zhenying; Yan, Caiqing; Zheng, Mei; Wu, Zhijun; Hu, Min; Wu, Yusheng; Zhu, Tong

    2017-05-01

    Aerosol acidity plays an important role in atmospheric chemistry. China emits large amounts of SO2, NOx, and NH3 into the atmosphere, but aerosol acidity is poorly characterized. In this study, simultaneous 1 h measurements of particulate and gaseous compositions along with the ISORROPIA-II thermodynamic equilibrium model were used to study aerosol acidity during severe haze episodes in northern China. The summed concentration of sulfate, nitrate, and ammonium was 135 ± 51 μg/m3 with a maximum of 250 μg/m3, and the gas-phase NH3 mixing ratio was 22 ± 9 ppb. Fine particles were moderately acidic, with a pH range of 3.0-4.9 and an average of 4.2, which was higher than those in the United States and Europe. Excess NH3 and high aerosol water content are responsible for the relatively lower aerosol acidity. These results suggest that the new pathways for sulfate production in China proposed by recent studies should be revisited.

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

    PubMed Central

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

    2017-01-01

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

  18. Characterization of TiN, TiC and Ti(C,N) in titanium-alloyed ferritic chromium steels focusing on the significance of different particle morphologies

    SciTech Connect

    Michelic, S.K.; Loder, D.; Reip, T.; Ardehali Barani, A.; Bernhard, C.

    2015-02-15

    Titanium-alloyed ferritic chromium steels are a competitive option to classical austenitic stainless steels owing to their similar corrosion resistance. The addition of titanium significantly influences their final steel cleanliness. The present contribution focuses on the detailed metallographic characterization of titanium nitrides, titanium carbides and titanium carbonitrides with regard to their size, morphology and composition. The methods used are manual and automated Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy as well as optical microscopy. Additional thermodynamic calculations are performed to explain the precipitation procedure of the analyzed titanium nitrides. The analyses showed that homogeneous nucleation is decisive at an early process stage after the addition of titanium. Heterogeneous nucleation gets crucial with ongoing process time and essentially influences the final inclusion size of titanium nitrides. A detailed investigation of the nuclei for heterogeneous nucleation with automated Scanning Electron Microscopy proved to be difficult due to their small size. Manual Scanning Electron Microscopy and optical microscopy have to be applied. Furthermore, it was found that during solidification an additional layer around an existing titanium nitride can be formed which changes the final inclusion morphology significantly. These layers are also characterized in detail. Based on these different inclusion morphologies, in combination with thermodynamic results, tendencies regarding the formation and modification time of titanium containing inclusions in ferritic chromium steels are derived. - Graphical abstract: Display Omitted - Highlights: • The formation and modification of TiN in the steel 1.4520 was examined. • Heterogeneous nucleation essentially influences the final steel cleanliness. • In most cases heterogeneous nuclei in TiN inclusions are magnesium based. • Particle morphology provides important information

  19. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. In the first quarterly report for this program the concept behind our approach was detailed, the structure of the program was presented, key technical issues were identified, preliminary designs were outlined, and technical progress was discussed. All progress made during the second quarter of this program related to experiment design of the proposed supercritical expansion technique for generating ultra-fine, iron compound, catalyst particles. This second quarterly report, therefore, presents descriptions of the final designs for most system components; diagnostic approaches and designs for determining particles size and size distributions, and the composition of the pre-expansion supercritical solution; and the overall technique progress made during this reporting period. 6 refs., 15 figs., 1 tab.

  20. Formation of fine particles enriched by V and Ni from heavy oil combustion: Anthropogenic sources and drop-tube furnace experiments

    NASA Astrophysics Data System (ADS)

    Jang, Ha-Na; Seo, Yong-Chil; Lee, Ju-Hyung; Hwang, Kyu-Won; Yoo, Jong-Ik; Sok, Chong-Hui; Kim, Seong-Heon

    The present study attempts to investigate the emission characteristics of fine particles with special emphasis on nickel and vanadium metal elements emitted from the heavy oil combustion in industrial boilers and power plant, which are typical anthropogenic sources in Korea. A series of combustion experiments were performed to investigate the emission characteristics of particles in the size range of submicron by means of drop-tube furnace with three major domestic heavy oils. Cascade impactors were utilized to determine the size distribution of particulates as well as to analyze the partitioning enrichment of vanadium and nickel in various size ranges. Experimental results were compared with field data of particle size distribution and metal partitioning at commercial utility boilers with heavy oil combustion. Such data were interpreted by chemical equilibrium and particle growth mechanism by means of computational models. In general, fine particles were the major portion of PM 10 emitted from the heavy oil combustion, with significant fraction of ultra-fine particles. The formation of ultra-fine particles through nucleation/condensation/coagulation from heavy oil combustion was confirmed by field and experimental data. Vanadium and nickel were more enriched in fine particles, particularly in ultra-fine particles. The conventional air pollution devices showed inefficient capability to remove ultra-fine particles enriched with hazardous transition metal elements such as vanadium and nickel.

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

    NASA Astrophysics Data System (ADS)

    2014-06-01

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

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

    PubMed Central

    Kanaya, Kazuo; Okamoto, Koji; Shimbo, Shinichiro

    2010-01-01

    Background and objectives It has been postulated that air-borne fine water particles (or mist) can induce asthma attacks in asthmatic children. To date, no attempt has been made to quantify the density of air-borne fine water particles with the aim of relating particle density to the etiology of asthma among children. The aim of this study was to investigate the relation of asthma attack frequency and the particle density evaluated in terms of light transmittance. Methods The density of fine water particles was quantified by measuring reductions in light transmittance at 250, 365 and 580 nm at an outdoor location when the surroundings were in darkness. The measurements were made at distances varying from 1 to 3 m from the light sources and performed every morning and evening for 1 year. Each day was separated into two half-day units [i.e., morning (from midnight to noon) and afternoon (from noon to midnight)]. The number of asthma attacks among 121 enrolled asthmatic children was counted for each unit. A possible correlation between the transmittance reduction and frequency of asthma attacks was assessed. Results A significant difference was observed in the extent of reduction in light transmittance at 365 nm between the units with asthma attacks and those without attacks. Furthermore, the reduction in the transmittance was more evident when more asthma attacks were recorded among the patients. No difference was detected in the reduction in light transmittance at 250 or 580 nm. Conclusions These results support the hypothesis that air-borne fine water particles are among the etiological factors that induce asthma attacks in asthmatic children. PMID:21432216

  3. Bioassay by intratracheal instillation for detection of lung toxicity due to fine particles in F344 male rats.

    PubMed

    Yokohira, Masanao; Takeuchi, Hijiri; Yamakawa, Keiko; Saoo, Kousuke; Matsuda, Yoko; Zeng, Yu; Hosokawa, Kyoko; Imaida, Katsumi

    2007-01-01

    We have established and documented an in vivo bioassay for detection of hazards with intratracheally instilled fine particles, which can be used for risk assessment of toxicity of materials inhaled into deep lung tissue of humans (Yokohira et al. Establishment of a bioassay system for detection of lung toxicity due to fine particle instillation: sequential histopathological changes with acute and subacute lung damage due to intratracheal instillation of quartz in F344 male rats. J Toxicol Pathol 2005;18:13-8). For validation we here examined toxicity of fine particles from quartz, hydrotalcite, potassium octatitanate, palladium oxide and carbon black with this bioassay. A total of 108, 10-week-old F344/DuCrj male rats were randomly divided into 8 groups. Groups 1 to 5 underwent intratracheal instillation of the 5 test particles (4 mg/rat) suspended in 0.2 ml vehicle (saline or 10% propylene glycol and 1% sodium carboxymethyl cellulose in saline: PG-CMC) with a specially designed aerolizer, and subgroups of 7 rats were killed on Days 1 and 28 thereafter. Groups 6 and 7 similarly were exposed to saline and PG-CMC, respectively, as vehicle controls, while group 8 was maintained untreated. Using histopathological changes and immunohistochemically assessed bromodeoxyuridine (BrdU) labeling indices, inducible nitric oxide synthase (iNOS) and matrix metalloproteinase-3 (MMP-3) levels as end points, the quartz treated group exhibited high toxicity, while the values for the other particle-treated groups pointed to only slight effects. Although additional efforts are needed to establish advantages and disadvantages with our bioassay, models featuring intratracheal instillation clearly can be useful for detection of acute or subacute lung toxicity due to inhaled fine particles by using histopathological scoring and markers like BrdU and iNOS for screening purposes in short-term studies.

  4. Separation and recovery of fine particles from waste circuit boards using an inflatable tapered diameter separation bed.

    PubMed

    Duan, Chenlong; Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

    2014-01-01

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

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

    PubMed Central

    Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution. PMID:25379546

  6. Characterization of non-exhaust coarse and fine particles from on-road driving and laboratory measurements.

    PubMed

    Kwak, Ji-hyun; Kim, Hongsuk; Lee, Janghee; Lee, Seokhwan

    2013-08-01

    We investigated the physical and chemical properties of non-exhaust coarse and fine particles generated by on-road driving and in a laboratory setting using a mobile sampling system. The on-road driving and laboratory measurements performed under constant speed driving revealed that particles produced by tire wear had a size distribution in the range of 2-3 μm, while roadway particles (RWPs) measured behind the front tire during on-road driving largely comprised crustal materials such as road surface wear particles and road dust as well as tire wear particles (TWPs). The mode diameters of particles obtained from on-road driving under cornering conditions were similar to those obtained under constant speed conditions, but with higher concentrations of crustal elements. Under braking conditions, the particulate matter (PM) concentrations of brake wear particles (BWPs) sampled near the brake pad increased significantly and were much higher than the concentration of RWPs during deceleration, indicating that BWPs are one of the main sources of non-exhaust emissions. In addition, BWPs observed from on-road and laboratory measurements had a broader PM size range (1-10 μm) than RWPs. Size-segregated chemical analysis of PM samples indicated that the concentrations of Fe and Ca were highest in the coarse fraction emitted under constant speed and cornering conditions, while Fe, Ba, and Ti were most abundant in the fine fraction emitted during braking events. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Improving Simulations of Fine Dust Surface Concentrations over the Western United States by Optimizing the Particle Size Distribution

    SciTech Connect

    Zhang, Li; Kok, Jasper F.; Henze, Daven; Li, Qinbin; Zhao, Chun

    2013-06-28

    To improve estimates of remote contributions of dust to fine particulate matter (PM2.5) in the western United States, new dust particle size distributions (PSDs) based upon scale-invariant fragmentation theory (Kok_PSD) with constraints from in situ measurements (IMP_PSD) are implemented in a chemical transport model (GEOS-Chem). Compared to initial simulations, this leads to reductions in the mass of emitted dust particles with radii <1.8 mm by 40%-60%. Consequently, the root-mean-square error in simulated fine dust concentrations compared to springtime surface observations in the western United States is reduced by 67%-81%. The ratio of simulated fine to coarse PM mass is also improved, which is not achievable by reductions in total dust emissions. The IMP_PSD best represents the PSD of dust transported from remote sources and reduces modeled PM2.5 concentrations up to 5 mg/m3 over the western United States, which is important when considering sources contributing to nonattainment of air quality standards. Citation: Zhang, L., J. F. Kok, D. K. Henze, Q. Li, and C. Zhao (2013), Improving simulations of fine dust surface concentrations over the western United States by optimizing the particle size distribution, Geophys. Res. Lett., 40, 3270-3275, doi:10.1002/grl.50591.

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

    SciTech Connect

    Jost O.L. Wendt

    2001-05-04

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NO{sub x} concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end we shall use an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined.

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

    SciTech Connect

    Jost O.L. Wendt

    2001-08-01

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end work is progress using an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. For the Third Quarter of this project we present our data on trace metal partitioning obtained from combustion of MSS and Gas, MSS and Coal and Coal and Gas alone.

  10. Apportionment of sources of fine and coarse particles in four major Australian cities by positive matrix factorisation

    NASA Astrophysics Data System (ADS)

    Chan, Yiu-Chung; Cohen, David D.; Hawas, Olga; Stelcer, Eduard; Simpson, Rod; Denison, Lyn; Wong, Neil; Hodge, Mary; Comino, Eva; Carswell, Stewart

    In this study, 437 days of 6-daily, 24-h samples of PM 2.5, PM 2.5-10 and PM 10 were collected over a 12-month period during 2003-2004 in Melbourne, Sydney, Brisbane and Adelaide. The elemental, ionic and polycyclic aromatic hydrocarbon composition of the particles were determined. Source apportionment was carried out by using the positive matrix factorisation software (PMF2). Eight factors were identified for the fine particle samples including 'motor vehicles', 'industry', 'other combustion sources', 'ammonium sulphates', 'nitrates', 'marine aerosols', 'chloride depleted marine aerosols' and 'crustal/soil dust'. On average combustion sources, secondary nitrates/sulphates and natural origin dust contributed about 46%, 25% and 26% of the mass of the fine particle samples, respectively. 'Crustal/soil dust', 'marine aerosols', 'nitrates' and 'road side dust' were the four factors identified for the coarse particle samples. On average natural origin dust contributed about 76% of the mass of the coarse particle samples. The contributions of the sources to the sample mass basically reflect the emission source characteristics of the sites. Secondary sulphates and nitrates were found to spread out evenly within each city. The average contribution of secondary nitrates to fine particles was found to be rather uniform in different seasons, rather than higher in winter as found in other studies. This could be due to the low humidity conditions in winter in most of the Australian cities which made the partitioning of the particle phase less favourable in the NH 4NO 3 equilibrium system. A linear relationship was found between the average contribution of marine aerosols and the distance of the site from the bay side. Wind erosion was found associated with higher contribution of crustal dust on average and episodes of elevated concentration of coarse particles in spring and summer.

  11. SWeRF--A method for estimating the relevant fine particle fraction in bulk materials for classification and labelling purposes.

    PubMed

    Pensis, Ingeborg; Luetzenkirchen, Frank; Friede, Bernd

    2014-05-01

    In accordance with the European regulation for classification, labelling and packaging of substances and mixtures (CLP) as well as the criteria as set out in the Globally Harmonized System (GHS), fine fraction of crystalline silica (CS) has been classified as a specific target organ toxicity, the specific organ in this case being the lung. Generic cut-off values for products containing a fine fraction of CS trigger the need for a method for the quantification of the fine fraction of CS in bulk materials. This article describes the so-called SWeRF method, the size-weighted relevant fine fraction. The SWeRF method combines the particle size distribution of a powder with probability factors from the EN 481 standard and allows the relevant fine fraction of a material to be calculated. The SWeRF method has been validated with a number of industrial minerals. This will enable manufacturers and blenders to apply the CLP and GHS criteria for the classification of mineral products containing RCS a fine fraction of CS.

  12. SWeRF—A Method for Estimating the Relevant Fine Particle Fraction in Bulk Materials for Classification and Labelling Purposes

    PubMed Central

    2014-01-01

    In accordance with the European regulation for classification, labelling and packaging of substances and mixtures (CLP) as well as the criteria as set out in the Globally Harmonized System (GHS), fine fraction of crystalline silica (CS) has been classified as a specific target organ toxicity, the specific organ in this case being the lung. Generic cut-off values for products containing a fine fraction of CS trigger the need for a method for the quantification of the fine fraction of CS in bulk materials. This article describes the so-called SWeRF method, the size-weighted relevant fine fraction. The SWeRF method combines the particle size distribution of a powder with probability factors from the EN 481 standard and allows the relevant fine fraction of a material to be calculated. The SWeRF method has been validated with a number of industrial minerals. This will enable manufacturers and blenders to apply the CLP and GHS criteria for the classification of mineral products containing RCS a fine fraction of CS. PMID:24389081

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

    PubMed

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

    2011-01-01

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

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

    PubMed

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

    2012-01-01

    Ambient coarse particles (diameter 1.8-10 microm), fine particles (diameter 0.1-1.8 microm), and ultrafine particles (diameter < 0.1 microm) in the atmosphere of the city of Shanghai were sampled during the summer of 2008 (from Aug 27 to Sep 08). Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX). Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence (SRXRF). Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 +/- 2.18, 8.82 +/- 3.52, and 2.02 +/- 0.41 microg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

  15. Residual ferrite formation in 12CrODS steels

    NASA Astrophysics Data System (ADS)

    Ukai, S.; Kudo, Y.; Wu, X.; Oono, N.; Hayashi, S.; Ohtsuka, S.; Kaito, T.

    2014-12-01

    Increasing Cr content from 9 to 12 mass% leads to superior corrosion and high-temperature oxidation resistances, and usually changes microstructure from martensite to a ferrite. To make transformable martensitic type of 12CrODS steels that have superior processing capability by using α/γ phase transformation, alloy design was conducted through varying nickel content. The structure of 12CrODS steels was successfully modified from full ferrite to a transformable martensite-base matrix containing ferrite. This ferrite consists of both equilibrium ferrite and a metastable residual ferrite. It was shown that the fraction of the equilibrium ferrite is predictable by computed phase diagram and formation of the residual ferrite was successfully evaluated through pinning of α/γ interfacial boundaries by oxide particles.

  16. Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full-scale chamber.

    PubMed

    Afshari, A; Matson, U; Ekberg, L E

    2005-04-01

    Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 +/- 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 microm to larger than 1.0 microm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 microm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a flat iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 x 10(7) particles per second) was observed when ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 x 10(10) particles per second) was observed in the radiator test. Humans and their activities are known to generate substantial amounts of particulate matter indoors and potentially they can have a strong influence on short-term exposure

  17. The preparation of copper fine particle paste and its application as the inner electrode material of a multilayered ceramic capacitor.

    PubMed

    Yonezawa, Tetsu; Takeoka, Shinsuke; Kishi, Hiroshi; Ida, Kiyonobu; Tomonari, Masanori

    2008-04-09

    Well size-controlled copper fine particles (diameter: 100-300 nm) were used as the inner electrode material of multilayered ceramic capacitors (MLCCs). The particles were dispersed in terpineol to form a printing paste with 50 wt% copper particles. The MLCC precursor modules prepared by the layer-by-layer printing of copper and BaTiO(3) particles were cosintered. Detailed observation of the particles, paste, and MLCCs before and after sintering was carried out by electron microscopy. The sintering temperature of Cu-MLCC was as low as 960 °C. The permittivity of these MLCCs was successfully measured with the copper inner layers.

  18. A fine-particle sodium tracer for long-range transport of the Kuwaiti oil-fire smoke

    NASA Astrophysics Data System (ADS)

    Lowenthal, Douglas H.; Borys, Randolph D.; Rogers, C. Fred; Chow, Judith C.; Stevens, Robert K.; Pinto, Joe P.; Ondov, John M.

    1993-04-01

    Evidence for long-range transport of the Kuwaiti oil-fire smoke during the months following the Persian Gulf War has been more or less indirect. For example, high concentrations of aerosol particles containing soot and oil-combustion tracers such as vanadium observed at great distances from the Middle East may have come from sources other than the oil fires. However, more-recent data on the aerosol chemistry of Kuwaiti oil-fire plumes provides a direct link between those fires and aerosols collected at the Mauna Loa Observatory (MLO) during the late spring and summer of 1991.By itself, temporal covariation of fine-particle concentrations of elemental carbon, sulfur, and the noncrustal V / Zn ratio in MLO aerosols suggested a link to large-scale oil-combustion sources, but not necessarily to Kuwait. However, high concentrations of fine-particle (0.1-1.0 µm diameter) NaCl were observed in the “white” oil-fire plumes over Kuwait during the summer of 1991. Further analysis of the Mauna Loa data indicates strong temporal correspondence between the noncrustal V / Zn and noncrustal Na / Zn ratios and strong consistency between the noncrustal Na to noncrustal V ratios found at Mauna Loa and in the Kuwaiti oil-fire plume. In the absence of other demonstrable sources of fine-particle Na, these relationships provide a direct link between the Kuwaiti oil fires and aerosol composition observed at MLO.

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

    PubMed Central

    Rich, David Q.; Özkaynak, Halûk; Crooks, James; Baxter, Lisa; Burke, Janet; Ohman-Strickland, Pamela; Thevenet-Morrison, Kelly; Kipen, Howard M.; Zhang, Junfeng; Kostis, John B.; Lunden, Melissa; Hodas, Natasha; Turpin, Barbara J.

    2013-01-01

    Previous studies have reported an increased risk of myocardial infarction (MI) associated with acute increases in PM concentration. Recently, we reported that MI/fine particle (PM2.5) associations may be limited to transmural infarctions. In this study, we retained data on hospital discharges with a primary diagnosis of acute myocardial infarction (using International Classification of Diseases 9th Revision [ICD-9] codes), for those admitted January 1, 2004 to December 31, 2006, who were ≥18 years of age, and were residents of New Jersey at the time of their MI. We excluded MI with a diagnosis of a previous MI and MI coded as a subendocardial infarction, leaving n=1563 transmural infarctions available for analysis. We coupled these health data with PM2.5 species concentrations predicted by the Community Multiscale Air Quality chemical transport model, ambient PM2.5 concentrations, and used the same case-crossover methods to evaluate whether the relative odds of transmural MI associated with increased PM2.5 concentration is modified by the PM2.5 composition/mixture (i.e. mass fractions of sulfate, nitrate, elemental carbon, organic carbon, and ammonium). We found the largest relative odds estimates on the days with the highest tertile of sulfate mass fraction (OR=1.13; 95% CI = 1.00, 1.27), nitrate mass fraction (OR=1.18; 95% CI = 0.98, 1.35), and ammonium mass fraction (OR=1.13; 95% CI = 1.00 1.28), and the lowest tertile of EC mass fraction (OR=1.17; 95% CI = 1.03, 1.34). Air pollution mixtures on these days were enhanced in pollutants formed through atmospheric chemistry (i.e., secondary PM2.5) and depleted in primary pollutants (e.g., EC). When mixtures were laden with secondary PM species (sulfate, nitrate, and/or organics) we observed larger relative odds of myocardial infarction associated with increased PM2.5 concentrations. Further work is needed to confirm these findings and examine which secondary PM2.5 component(s) is/are responsible for an acute MI

  20. An intratracheal instillation bioassay system for detection of lung toxicity due to fine particles in f344 rats.

    PubMed

    Yokohira, Masanao; Kuno, Toshiya; Yamakawa, Keiko; Hashimoto, Nozomi; Ninomiya, Fumiko; Suzuki, Satoshi; Saoo, Kousuke; Imaida, Katsumi

    2009-03-01

    It is an urgent priority to establish in vivo bioassays for detection of hazards related to fine particles, which can be inhaled into deep lung tissue by humans. In order to establish an appropriate bioassay for detection of lung damage after particle inhalation, several experiments were performed in rats using quartz as a typical lung toxic particle. The results of pilot experiments suggest that Days 1 and 28 after intratracheal instillation of 2 mg of fine test particles in vehicle are most appropriate for detection of acute and subacute inflammatory changes, respectively. Furthermore, the BrdU incorporation on Day 1 and the iNOS level on Day 28 proved to be suitable end-point markers for this purpose. An examination of the toxicity of a series of particles was performed with the developed bioassay. Although some materials, including nanoparticles, demonstrated toxicity that was too strong for sensitive assessment, a ranking order could be clarified. The bioassay thus appears suitable for rapid hazard identification with a possible ranking of the toxicity of various particles at single concentrations.

  1. Analysis of primary fine particle national ambient air quality standard metrics.

    PubMed

    Johnson, Philip R S; Graham, John J

    2006-02-01

    In accordance with the Clean Air Act, the U.S. Environmental Protection Agency (EPA) is currently reviewing its National Ambient Air Quality Standards for particulate matter, which are required to provide an adequate margin of safety to populations, including susceptible subgroups. Based on the latest scientific, health, and technical information about particle pollution, EPA staff recommends establishing more protective health-based fine particle standards. Since the last standards review, epidemiologic studies have continued to find associations between short-term and long-term exposure to particulate matter and cardiopulmonary morbidity and mortality at current pollution levels. This study analyzed the spatial and temporal variability of fine particulate (PM2.5) monitoring data for the Northeast and the continental United States to assess the protectiveness of various levels, forms, and combinations of 24-hr and annual health-based standards currently recommended by EPA staff and the Clean Air Scientific Advisory Committee. Recommended standards have the potential for modest or substantial increases in protection in the Northeast, ranging from an additional 13-83% of the population of the region who are living in areas not likely to meet new standards and thereby benefiting from compliance with more protective air pollution controls. Within recommended standard ranges, an optimal 24-hr (98th percentile)/annual standard suite occurs at 30/12 microg/m3, providing short- and long-term health protection for a substantial percentage of both Northeast (84%) and U.S. (78%) populations. In addition, the Northeast region will not benefit as widely as the nation as a whole if less stringent standards are selected. Should the 24-hr (98th percentile) standard be set at 35 microg/m3, Northeast and U.S. populations will receive 16-48% and 7-17% less protection than a 30 microg/m3 standard, respectively, depending on the level of the annual standard. A 30/12 microg/m3 standard

  2. Measurement of fine particles and smoking activity in a statewide survey of 36 California Indian casinos.

    PubMed

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

    2011-01-01

    Despite California's 1994 statewide smoking ban, exposure to secondhand smoke (SHS) continues in California's Indian casinos. Few data are available on exposure to airborne fine particles (PM₂.₅) in casinos, especially on a statewide basis. We sought to measure PM₂.₅ concentrations in Indian casinos widely distributed across California, exploring differences due to casino size, separation of smoking and non-smoking areas, and area smoker density. A selection of 36 out of the 58 Indian casinos throughout California were each visited for 1-3 h on weekend or holiday evenings, using two or more concealed monitors to measure PM₂.₅ concentrations every 10 s. For each casino, the physical dimensions and the number of patrons and smokers were estimated. As a preliminary assessment of representativeness, we also measured eight casinos in Reno, NV. The average PM₂.₅ concentration for the smoking slot machine areas (63 μg/m³) was nine times as high as outdoors (7 μg/m³), whereas casino non-smoking restaurants (29 μg/m³) were four times as high. Levels in non-smoking slot machine areas varied: complete physical separation reduced concentrations almost to outdoor levels, but two other separation types had mean levels that were 13 and 29 μg/m³, respectively, higher than outdoors. Elevated PM₂.₅ concentrations in casinos can be attributed primarily to SHS. Average PM₂.₅ concentrations during 0.5-1 h visits to smoking areas exceeded 35 μg/m³ for 90% of the casino visits.

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

    PubMed

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

    2017-06-23

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

  4. Aerosol fine fraction in the Venice Lagoon: Particle composition and sources

    NASA Astrophysics Data System (ADS)

    Prodi, F.; Belosi, F.; Contini, D.; Santachiara, G.; Di Matteo, L.; Gambaro, A.; Donateo, A.; Cesari, D.

    2009-04-01

    The work presents a characterisation of aerosol sampled during three campaigns conducted in the Venice Lagoon from 30 June to 21 July 2004, from 15 February to 10 March 2005 and from 8 May to 25 May 2006. The results yield information about the physical-chemical characteristics of fine aerosol, the possible sources and its fate. Sulphate (SO 42-), nitrate (NO 3-) and ammonium (NH 4+) are identified as the main water soluble components. The sum of these ions in the spring campaign 2006 varies from 51% to nearly 100% of PM2.5 fraction aerosol. NH 4+ is found to be significantly correlated to non-sea-salt sulphate (nss-SO 42-) and NO 3-, thus indicating the prevalent presence of ammonium nitrate and sulphate. The overall lack of a clear diurnal and seasonal cycle of sulphate suggests a transport from the Po Valley, while the diurnal and seasonal profile of nitrate concentrations suggests a prevalence of local generation. Sulphates from sea water through oxidation of dimethylsulfide (DMS) are not negligible (about 10% of the anthropogenic sulphate). The marine aerosol contribution to PM1 and PM2.5 fractions, calculated using Na + as a tracer of sea-salts, is low (range 1-6%). In some cases chlorine depletion is observed. The content of chlorine in the aerosol particle is mostly higher than expected for marine environments (considered on the basis of Cl -/Na + ratio). Therefore, specific sources for the element have been suggested. Oxalic acid anion, which accounts for 55% of the organic compounds examined, presents mean values 180 ng m - 3 and 161 ng m - 3 in the winter and spring campaigns, comparable with reported values in low polluted urban areas. In the winter campaign there is a high correlation between formate and acetate ( R2 = 0.93), suggesting that a common source makes a high contribution to the measured concentrations.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

  8. Determinants of fine particle (PM 2.5) personal exposure levels in transport microenvironments, London, UK

    NASA Astrophysics Data System (ADS)

    Adams, H. S.; Nieuwenhuijsen, M. J.; Colvile, R. N.

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

  9. Temporal and Spatial Variations in Fine and Coarse Particles in Seoul, Korea

    SciTech Connect

    Ghim, Young Sung; Chang, Young-Soo; Jung, Kweon

    2015-06-01

    Concentrations of fine (PM2.5) and coarse particles (PM10 -2.5), whose diameters are less 2.5 µm, and between 2.5 and 10 µm, respectively, at ambient air monitoring stations in Seoul between 2002 and 2008 were analyzed. Effects of Asian dust are mainly manifested as concentration spikes of PM10 - 2.5 but were considerable on PM2.5 levels in 2002 when Asian dust storms were the strongest. Excluding the effects of Asian dust, annual average PM2.5 showed a downward trend. Despite a similarity in year - to - year variations, PM10- 2.5, mostly affected by fugitive dust emissions, and CO and NO2, primarily affected by motor vehicle emissions, did not show a decrease. PM2.5 along with CO and NO2 had the highest values during the morning rush hour. PM10 - 2.5 peak lagged about one hour behind that of PM2.5 because of fugitive dust emissions despite an increasing mixing height. On high PM2.5 days, PM2. 5 peaks occurred two hours later than usual as the effects of secondary formation became more important. A test for the spatial variabilities shows that PM10 - 2.5, which is known to be greatly influenced by local effects, is lower in its correlation coeffic ient and higher in its coefficient of divergence (COD, which serves as an indicator for spatial variability) than PM2.5, albeit that the difference between the two is small. The average COD of PM2.5 among monitoring stations was about 0.2 but was lowered t o 0.13 when considering high PM2.5 days only, which signifies that spatial uniformity increases significantly.

  10. A Biopersistence Study following Exposure to Chrysotile Asbestos Alone or in Combination with Fine Particles

    PubMed Central

    Bernstein, D. M.; Donaldson, K.; Decker, U.; Gaering, S.; Kunzendorf, P.; Chevalier, J.; Holm, S. E.

    2008-01-01

    In designing a study to evaluate the inhalation biopersistence of a chrysotile asbestos that was used as a component of a joint-compound, a feasibility study was initiated to evaluate the short-term biopersistence of the chrysotile alone and of the chrysotile in combination witht the sanded reformulated joint-compound. Two groups of Wistar rats were exposed to either 7RF3 chrysotile (Group 2) or to 7RF3 chrysotile combined with aerosolized sanded joint-compound (Group 3). In addition, a control group was exposed to flltered-air. The chrysotile used in the Ready Mix joint compound is rapidly removed from the lung. The chrysotile alone exposure group had a clearance half-time of fibers L > 20 μm of 2.2 days; in the chrysotile plus sanded exposure group the clearance half-time of fibers L > 20 μm was 2.8 days. However, across all size ranges there was approximately an order of magnitude decrease in the mean number of fibers remaining in the lungs of Group 3 as compared to Group 2 despite similiar aerosol exposures. Histopathological examination showed that the chrysotile exposed lungs had the same appearance as the flltered-air controls. This study uniquely illustrates that additional concurrent exposure to an aerosol of the sanded joint-compound, with large numbers of fine-particles depositing in the lungs, accelerates the recruitment of macrophages, resulting in a tenfold decrease in the number of fibers remaining in the lung. The increased number of macrophages in the chrysotile/sanded joint exposure group was confirmed histologically, with this being the only exposure-related histological finding reported. PMID:18788018

  11. Differentiating the effects of fine and coarse particles on daily mortality in Shanghai, China.

    PubMed

    Kan, Haidong; London, Stephanie J; Chen, Guohai; Zhang, Yunhui; Song, Guixiang; Zhao, Naiqing; Jiang, Lili; Chen, Bingheng

    2007-04-01

    The findings on health effects of ambient fine particles (PM2.5) and coarse particles (PM10-2.5) remain inconsistent. In China, PM2.5 and PM10-2.5 are not the criteria air pollutants, and their monitoring data are scarce. There have been no epidemiological studies of health effects of PM2.5 and PM10-2.5 simultaneously in China. We conducted a time series study to examine the acute effects of PM2.5 and PM10-2.5 on daily mortality in Shanghai, China from Mar. 4, 2004 to Dec. 31, 2005. We used the generalized additive model (GAM) with penalized splines to analyze the mortality, air pollution and covariate data. The average concentrations of PM2.5 and PM10-2.5 were 56.4 microg/m3 and 52.3 microg/m3 in our study period, and PM2.5 constituted around 53.0% of the PM10 mass. Compared with the Global Air Quality Guidelines set by World Health Organization (10 microg/m3 for annual mean) and U.S. National Ambient Air Quality Standards (15 microg/m3 for annual mean), the PM2.5 level in Shanghai was much higher. We found that PM2.5 was associated with the death rates from all causes and from cardiorespiratory diseases in Shanghai. We did not find a significant effect of PM10-2.5 on mortality outcomes. A10 microg/m3 increase in the 2-day moving average (lag01) concentration of PM2.5 corresponded to 0.36% (95% CI 0.11%, 0.61%), 0.41% (95% CI 0.01%, 0.82%) and 0.95% (95% CI 0.16%, 1.73%) increase of total, cardiovascular and respiratory mortality. For PM10-2.5, the effects were attenuated and less precise. Our analyses provide the first statistically significant evidence in China that PM2.5 has an adverse effect on population health and strengthen the rationale for further limiting levels of PM2.5 in outdoor air in Shanghai.

  12. Lung deposition of fine and ultrafine particles outdoors and indoors during a cooking event and a no activity period.

    PubMed

    Mitsakou, C; Housiadas, C; Eleftheriadis, K; Vratolis, S; Helmis, C; Asimakopoulos, D

    2007-04-01

    Some indoor activities increase the number concentration of small particles and, hence, enhance the dose delivered to the lungs. The received particle dose indoors may exceed noticeably the dose from ambient air under routine in-house activities like cooking. In the present work, the internal dose by inhalation of ultrafine and fine particles is assessed, using an appropriate mechanistic model of lung deposition, accommodating aerosol, and inhalation dynamics. The analysis is based on size distribution measurements (10-350 nm) of indoor and outdoor aerosol number concentrations in a typical residence in Athens, Greece. Four different cases are examined, namely, a cooking event, a no activity period indoors and the equivalent time periods outdoors. When the cooking event (frying of bacon-eggs with a gas fire) occurred, the amount of deposited particles deep into the lung of an individual indoors exceeded by up to 10 times the amount received by an individual at the same time period outdoors. The fine particle deposition depends on the level of physical exertion and the hygroscopic properties of the inhaled aerosol. The dose is not found linearly dependant on the indoor/outdoor concentrations during the cooking event, whereas it is during the no activity period. The necessity for determining the dose in specific regions of the human lung, as well as the non-linear relationship between aerosol concentration and internal dose makes the application of dosimetry models important. Lung dose of fine and ultrafine particles, during a cooking event, is compared with the dose at no indoor activity and the dose received under outdoor exposure conditions. The dose is expressed in terms of number or surface of deposited particles. This permits to address the dosimetry of very small particles, which are released by many indoor sources but represent a slight fraction of the particulate matter mass. The enhancement of the internal dose resulting from fine and ultrafine particles

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

    PubMed

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

    2014-02-07

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

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

    PubMed

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

    2015-09-01

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

  15. Use of the electrical aerosol detector as an indicator of the surface area of fine particles deposited in the lung.

    PubMed

    Wilson, William E; Stanek, John; Han, Hee-Siew Ryan; Johnson, Tim; Sakurai, Hiromu; Pui, David Y H; Turner, Jay; Chen, Da-Ren; Duthie, Scott

    2007-02-01

    Because of recent concerns about the health effects of ultrafine particles and the indication that particle toxicity is related to surface area, we have been examining techniques for measuring parameters related to the surface area of fine particles, especially in the 0.003- to 0.5-microm size range. In an earlier study, we suggested that the charge attached to particles, as measured by a prototype of the Electrical Aerosol Detector (EAD, TSI Inc., Model 3070), was related to the 1.16 power of the mobility diameter. An inspection of the pattern of particle deposition in the lung as a function of particle size suggested that the EAD measurement might be a useful indicator of the surface area of particles deposited in the lung. In this study, we calculate the particle surface area (micrometer squared) deposited in the lung per cubic centimeter of air inhaled as a function of particle size using atmospheric particle size distributions measured in Minneapolis, MN, and East St. Louis, IL. The correlations of powers of the mobility diameter, Dx, were highest for X = 1.1-1.6 for the deposited surface area and for X = 1.25 with the EAD signal. This overlap suggested a correspondence between the EAD signal and the deposited surface area. The correlation coefficients of the EAD signal and particle surface area deposited in the alveolar and tracheobronchial regions of the lung for three breathing patterns are in the range of Pearson's r = 0.91-0.95 (coefficient of determination, R2 = 0.82-0.90). These statistical relationships suggest that the EAD could serve as a useful indicator of particle surface area deposited in the lung in exposure and epidemiologic studies of the human health effects of atmospheric particles and as a measure of the potential surface area dose for the characterization of occupational environments.

  16. Fine sediment and nutrient dynamics related to particle size and floc formation in a Burdekin River flood plume, Australia.

    PubMed

    Bainbridge, Zoe T; Wolanski, Eric; Alvarez-Romero, Jorge G; Lewis, Stephen E; Brodie, Jon E

    2012-01-01

    The extreme 2010-2011 wet season resulted in highly elevated Burdekin River discharge into the Great Barrier Reef lagoon for a period of 200 days, resulting in a large flood plume extending >50km offshore and >100km north during peak conditions. Export of suspended sediment was dominated by clay and fine silt fractions and most sediment initially settled within ∼10km of the river mouth. Biologically-mediated flocculation of these particles enhanced deposition in the initial low salinity zone. Fine silt and clay particles and nutrients remaining in suspension, were carried as far as 100km northward from the mouth, binding with planktonic and transparent exopolymer particulate matter to form large floc aggregates (muddy marine snow). These aggregates, due to their sticky nature, likely pose a risk to benthic organisms e.g. coral and seagrass through smothering, and also by contributing to increased turbidity during wind-induced resuspension events. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. FINE PARTICLES ARE MORE STRONGLY ASSOCIATED THAN COARSE PARTICLES WITH ACUTE REPIRATORY HEALTH EFFECTS IN SCHOOL CHILDREN

    EPA Science Inventory

    Numerous studies have reported associations between airborne particles and a range of respiratory outcomes from symptoms to mortality. Current attention has been focused on the characteristics of these particles responsible for the adverse health effects. We have reanalyzed three...

  18. Effects of ambient coarse, fine, and ultrafine particles and their biological constituents on systemic biomarkers: a controlled human exposure study.

    PubMed

    Liu, Ling; Urch, Bruce; Poon, Raymond; Szyszkowicz, Mieczyslaw; Speck, Mary; Gold, Diane R; Wheeler, Amanda J; Scott, James A; Brook, Jeffrey R; Thorne, Peter S; Silverman, Frances S

    2015-06-01

    Ambient coarse, fine, and ultrafine particles have been associated with mortality and morbidity. Few studies have compared how various particle size fractions affect systemic biomarkers. We examined changes of blood and urinary biomarkers following exposures to three particle sizes. Fifty healthy nonsmoking volunteers, mean age of 28 years, were exposed to coarse (2.5-10 μm; mean, 213 μg/m3) and fine (0.15-2.5 μm; mean, 238 μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (< 0.3 μm; mean, 136 μg/m3) and filtered medical air. Exposures lasted 130 min, separated by ≥ 2 weeks. Blood/urine samples were collected preexposure and 1 hr and 21 hr postexposure to determine blood interleukin-6 and C-reactive protein (inflammation), endothelin-1 and vascular endothelial growth factor (VEGF; vascular mediators), and malondialdehyde (lipid peroxidation); as well as urinary VEGF, 8-hydroxy-deoxy-guanosine (DNA oxidation), and malondialdehyde. Mixed-model regressions assessed pre- and postexposure differences. One hour postexposure, for every 100-μg/m3 increase, coarse CAP was associated with increased blood VEGF (2.41 pg/mL; 95% CI: 0.41, 4.40) in models adjusted for O3, fine CAP with increased urinary malondialdehyde in single- (0.31 nmol/mg creatinine; 95% CI: 0.02, 0.60) and two-pollutant models, and ultrafine CAP with increased urinary 8-hydroxydeoxyguanosine in single- (0.69 ng/mg creatinine; 95% CI: 0.09, 1.29) and two-pollutant models, lasting < 21 hr. Endotoxin was significantly associated with biomarker changes similar to those found with CAPs. Ambient particles with various sizes/constituents may influence systemic biomarkers differently. Endotoxin in ambient particles may contribute to vascular mediator changes and oxidative stress.

  19. Microstructural change during superplastic deformation of δ-ferrite/austenite duplex stainless steel

    NASA Astrophysics Data System (ADS)

    Maehara, Y.; Ohmori, Y.

    1987-05-01

    Superplasticity of a 25 pct Cr-6.5 pct Ni-3 pct Mo-0.14 pct N δ/γ duplex stainless steel has been studied with particular emphasis on the microstructural change during deformation. Two large superplastic elongations are obtained at temperatures around 1323 K in δ/γ duplex phase region and 1173 K where σ phase particles precipitate dynamically at a strain rate of ~10-3 s-1. During deformation in the higher temperature region, fine Widmanstätten γ particles coarsen and coarse γ grains formed during the prior treatments are broken into spherical particles, resulting in a homogeneous dispersion of γ particles within the σ-ferrite matrix. The dynamic recrystallization of soft σ-ferrite matrix occurs locally in the region where the strain reaches some critical value, and the final microstructure consists of equiaxed σ and γ grains. In the case of lower temperature deformation, a eutectoid decomposition of δ-ferrite into γ and σ phases occurs. The relatively soft γ grains which are severely deformed by hard σ particles recrystallize dynamically, and these processes lead to the γ/σ equiaxed duplex structure. The extremely large superplasticity of this alloy can mainly be explained in terms of the above microstructural change during deformation.

  20. Microstructural change during superplastic deformation of δ-ferrite/austenite duplex stainless steel

    NASA Astrophysics Data System (ADS)

    Maehara, Y.; Ohmori, Y.

    1987-04-01

    Superplasticity of a 25 pct Cr-6.5 pct Ni-3 pct Mo-0.14 pct N δ/γ duplex stainless steel has been studied with particular emphasis on the microstructural change during deformation. Two large superplastic elongations are obtained at temperatures around 1323 K in δ/γ duplex phase region and 1173 K where σ phase particles precipitate dynamically at a strain rate of 10-3 s-1. During deformation in the higher temperature region, fine Widmanstätten γ particles coarsen and coarse γ grains formed during the prior treatments are broken into spherical particles, resulting in a homogeneous dispersion of γ particles within the σ-ferrite matrix. The dynamic recrystallization of soft σ-ferrite matrix occurs locally in the region where the strain reaches some critical value, and the final microstructure consists of equiaxed σ and γ grains. In the case of lower temperature deformation, a eutectoid decomposition of δ-ferrite into γ and σ phases occurs. The relatively soft γ grains which are severely deformed by hard σ particles recrystallize dynamically, and these processes lead to the γ/σ equiaxed duplex structure. The extremely large superplasticity of this alloy can mainly be explained in terms of the above microstructural change during deformation.

  1. Synthesis and magnetic properties of nanostructured spinel ferrites using a glycine-nitrate process

    NASA Astrophysics Data System (ADS)

    Kikukawa, Nobuyuki; Takemori, Makoto; Nagano, Yoshinobu; Sugasawa, Masami; Kobayashi, Satoru

    2004-12-01

    To prepare zinc-substituted spinel-type ferrite fine particles of M1-xZnxFe2O4 (M=Mg, Mn, Co, Ni, Cu, (Li, Fe) x=0-1) with good crystallinity and stoichiometry, the authors investigated a glycine-nitrate process. The product powder was an agglomerate of fine particles whose typical diameter was several tens of nanometers. X-ray diffraction patterns revealed that the produced particles were mono-phase in almost all reaction systems. Energy-dispersive X-ray spectroscopy microanalysis of the product particles (Mn-Zn-Fe-O) revealed that the distributions of Mn/Fe ratio and Zn/Fe ratio were highly sharp both within the agglomerate and between agglomerates.

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

    SciTech Connect

    Shimizu, S.; Shimizu, T.; Thomas, H. M.; Morfill, G. E.; Jacob, W.

    2011-11-15

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

  3. Fine-particle sodium tracer for long-range transport of the Kuwaiti oil-fire smoke

    SciTech Connect

    Lowenthal, D.H.; Borys, R.D.; Rogers, C.F.; Chow, J.C.; Stevens, R.K.

    1993-04-23

    Evidence for long-range transport of the Kuwaiti oil-fire smoke during the months following the Persian Gulf War has been more or less indirect. However, more-recent data on the aerosol chemistry of Kuwaiti oil-fire plumes provides a direct link between those fires and aerosols collected at the Mauna Loa Observatory (MLO) during the late spring and summer of 1991. By itself, temporal covariation of fine-particle concentrations of elemental carbon, sulfur, and the noncrustal V/Zn ratio in MLO aerosols suggested a link to large-scale oil-combustion sources, but not necessarily to Kuwait. However, high concentrations of fine-particle (0.1-1.0 microm diameter) NaCl were observed in the 'white' oil-fire plumes over Kuwait during the summer of 1991. In the absence of other demonstratable sources of fine-particle Na, these relationships provide a direct link between the Kuwaiti oil-fires and aerosol composition observed at MLO. (Copyright (c) 1993 American Geophysical Union.)

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

    PubMed

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

    2015-07-21

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

  5. Solid dispersion particles of amorphous indomethacin with fine porous silica particles by using spray-drying method.

    PubMed

    Takeuchi, Hirofumi; Nagira, Shinsuke; Yamamoto, Hiromitsu; Kawashima, Yoshiaki

    2005-04-11

    The solid dispersion particles of indomethacin (IMC) were prepared with different types of silica, non-porous (Aerosil 200) or porous silica (Sylysia 350) by using spray-drying method. Powder X-ray diffraction analysis showed that IMC in solid dispersion particles is in amorphous state irrespective of the type of silica formulated. In DSC analysis, the melting peak of IMC in solid dispersion particles with Sylysia 350 shifted to lower temperature than that in solid dispersion particles with Aerosil 200 although the peak of each solid dispersion particles was much smaller than that of original IMC crystals. Dissolution property of IMC was remarkably improved by formulating the silica particles to the solid dispersion particles. In comparing the effect of the type of the silica particles, the dissolution rate of solid dispersion particles with Sylysia 350 was faster than that with Aerosil 200. The formulation amount of IMC did not affect on the amorphous state of IMC in the resultant solid dispersion particles in powder X-ray diffraction patterns. However, the area of the melting peak of IMC in the solid dispersion particles increased and an exothermic peak owing to recrystallization was observed with increasing the IMC content in the DSC patterns. The dissolution rate of IMC from the solid dispersion particles with Sylysia 350 was faster than that of Aerosil 200 irrespective of IMC content. In stability test, amorphous IMC in the solid dispersion particles with each silica particles did not crystallize under storing at severe storage conditions (40 degrees C, 75% RH) for 2 months, while amorphous IMC without silica easily crystallized under same conditions.

  6. Synthesis and Characterization of Nickel Zinc Ferrite

    NASA Astrophysics Data System (ADS)

    Kurian, Manju; Nair, Divya S.

    2011-10-01

    Nano crystalline mixed ferrites can be prepared through different methods. In the present work a comparison was made on sol-gel auto combustion method and co-precipitation method by preparing Nickel Zinc Ferrite. The prepared samples were calcined at different temperatures and were characterized by powder XRD, FTIR. X-ray diffraction analysis indicated the formation of ferrite in nanophase. The lattice parameter was found to be in the range 8.31-8.41Ao. This confirms that nano crystalline ferrite samples are in the cubic spinel structure. An average nano crystalline size was estimated from XRD by the Scherrer's equation. FTIR study also confirms the formation of ferrites. Sol-gel auto combustion technique was superior to co-precipitation method for producing single phase nano particles with smaller crystallite size.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  8. Determining contributions of biomass burning and other sources to fine particle contemporary carbon in the western United States

    NASA Astrophysics Data System (ADS)

    Holden, Amanda S.; Sullivan, Amy P.; Munchak, Leigh A.; Kreidenweis, Sonia M.; Schichtel, Bret A.; Malm, William C.; Collett, Jeffrey L., Jr.

    2011-02-01

    Six-day integrated fine particle samples were collected at urban and rural sampling sites using Hi-Volume samplers during winter and summer 2004-2005 as part of the IMPROVE (Interagency Monitoring of PROtected Visual Environments) Radiocarbon Study. Filter samples from six sites (Grand Canyon, Mount Rainier, Phoenix, Puget Sound, Rocky Mountain National Park, and Tonto National Monument) were analyzed for levoglucosan, a tracer for biomass combustion, and other species by High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). Contemporary carbon concentrations were available from previous carbon isotope measurements at Lawrence Livermore National Laboratory. Primary contributions of biomass burning to measured fine particle contemporary carbon were estimated for residential wood burning (winter) and wild/prescribed fires (summer). Calculated contributions ranged from below detection limit to more than 100% and were typically higher at rural sites and during winter. Mannitol, a sugar alcohol emitted by fungal spores, was analyzed and used to determine contributions of fungal spores to fine particle contemporary carbon. Contributions reached up to 13% in summer samples, with higher contributions at rural sites. Concentrations of methyltetrols, oxidation products of isoprene, were also measured by HPAEC-PAD. Secondary organic aerosol (SOA) from isoprene oxidation was estimated to contribute up to 22% of measured contemporary carbon. For each sampling site, a substantial portion of the contemporary carbon was unexplained by primary biomass combustion, fungal spores, or SOA from isoprene oxidation. This unexplained fraction likely contains contributions from other SOA sources, including oxidation products of primary smoke emissions and plant emissions other than isoprene, as well as other primary particle emissions from meat cooking, plant debris, other biological aerosol particles, bio-diesel combustion, and other sources. Loss

  9. Characteristics of water-soluble ions and carbon in fine and coarse particles collected near an open burning site

    NASA Astrophysics Data System (ADS)

    Lin, Chih-Chung; Huang, Kuo-Lin; Tsai, Jen-Hsiung; Lee, Wen-Jhy; Chen, Shui-Jen; Lin, Shao-Kai

    2012-05-01

    This study investigates the chemical characteristics of particles that were collected from the open burning of wax apple agricultural waste, and evaluates the impact of such burning on regional air quality. The water-soluble ions, elemental carbon (EC), and organic carbon (OC) in fine (Dp ≤ 2.5 μm) and coarse (2.5 < Dp ≤ 10 μm) particles were collected using a micro-orifice uniform deposition impactor (MOUDI) and two Dichot samplers. The average PM2.5/PM10 ratio during open burning (0.90) was higher than those both before and after burning (0.57 and 0.55, respectively). The particle distributions before and during burning were bi-modal and uni-modal, respectively. During the open burning, the OC or K+ content markedly increased; however, that of secondary aerosol (NH4+, NO3- and SO42-) decreased. The Na+/Cl- molar ratios of fine particles before, after, and during the open burning 0.40, 0.18, and 0.24, respectively; however, the corresponding (Na+ + K+)/Cl- molar ratios were 0.74, 0.99, and 0.39, respectively. OC, K+ and Cl- were quite abundant in the open burning of agricultural waste (wax apple), and the OC/Na+, K+/Na+, and Cl-/Na+ (mass) ratios in fine particles (318, 10.2, and 10.5, respectively) may be used as reference indexes associated with the open burning of wax apple waste.

  10. Fine particle air pollution and secondhand smoke exposures and risks inside 66 US casinos.

    PubMed

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

    2011-05-01

    Smoking bans often exempt casinos, exposing occupants to fine particles (PM(2.5)) from secondhand smoke. We quantified the relative contributions to PM(2.5) from both secondhand smoke and infiltrating outdoor sources in US casinos. We measured real-time PM(2.5), particulate polycyclic aromatic hydrocarbons (PPAH), and carbon dioxide (CO(2)) (as an index of ventilation rate) inside and outside 8 casinos in Reno, Nevada. We combined these data with data from previous studies, yielding a total of 66 US casinos with smoking in California, Delaware, Nevada, New Jersey, and Pennsylvania, developing PM(2.5) frequency distributions, with 3 nonsmoking casinos for comparison. Geometric means for PM(2.5) were 53.8 μg/m(3) (range 18.5-205 μg/m(3)) inside smoking casinos, 4.3 μg/m(3) (range 0.26-29.7 μg/m(3)) outside those casinos, and 3.1 μg/m(3) (range 0.6-9 μg/m(3)) inside 3 nonsmoking casinos. In a subset of 21 Reno and Las Vegas smoking casinos, PM(2.5) in gaming areas averaged 45.2 μg/m(3) (95% CI, 37.7-52.7 μg/m(3)); adjacent nonsmoking casino restaurants averaged 27.2 μg/m(3) (95% CI, 17.5-36.9 μg/m(3)), while PM(2.5) outside the casinos averaged 3.9 μg/m(3) (95% CI, 2.5-5.3 μg/m(3)). For a subset of 10 Nevada and Pennsylvania smoking casinos, incremental (indoor-outdoor) PM(2.5) was correlated with incremental PPAH (R(2)=0.