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Sample records for sub-micron metallic particles

  1. Short range investigation of sub-micron zirconia particles

    Energy Technology Data Exchange (ETDEWEB)

    Caracoche, M C; Martinez, J A [Departamento de Fisica, IFLP, Facultad de Ciencias Exactas, CICPBA, Universidad Nacional de La Plata (Argentina); Rivas, P C [IFLP-CONICET, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata (Argentina); Bondioli, F; Cannillo, V [Dipartimento di Ingegniria dei Materiali e dell' Ambiente, Facolta di Ingegneria, Universita di Modena e Reggio Emilia (Italy); Ferrari, A M, E-mail: cristina@fisica.unlp.edu.a [Dipartimento di Scienza a Metodi dell' Ingegneria, Universita di Modena e Reggio Emilia (Italy)

    2009-05-01

    The Perturbed Angular Correlations technique was used to determine the configurations around Zirconium ions and their thermal behavior in non-aggregated sub-micron zirconia spherical particles. Three residues containing- Zr surroundings were determined for the non-crystalline starting particles, which were identified under the assumption of a certain chemical reactions sequence during synthesis. While the one made up mainly by hydroxyl groups was common to both samples, the two involving mainly organic residues were particle size dependent. Upon crystallization, both samples stabilized in the t'- and t- tetragonal forms and the Xc-cubic form but their amounts and temperatures of appearance were different. On heating, the structure of the smaller particles became gradually monoclinic achieving total degradation upon the subsequent cooling to RT.

  2. Discovering sub-micron ice particles across Dione' surface

    Science.gov (United States)

    Scipioni, Francesca; Schenk, Pual; Tosi, Federico; Clark, Roger; Dalle Ore, Cristina; Combe, Jean-Philippe

    2015-11-01

    Water ice is the most abundant component of Saturn’s mid-sized moons. However, these moons show an albedo asymmetry - their leading sides are bright while their trailing side exhibits dark terrains. Such differences arise from two surface alteration processes: (i) the bombardment of charged particles from the interplanetary medium and driven by Saturn’s magnetosphere on the trailing side, and (ii) the impact of E-ring water ice particles on the satellites’ leading side. As a result, the trailing hemisphere appears to be darker than the leading side. This effect is particularly evident on Dione's surface. A consequence of these surface alteration processes is the formation or the implantation of sub-micron sized ice particles.The presence of such particles influences and modifies the surfaces' spectrum because of Rayleigh scattering by the particles. In the near infrared range of the spectrum, the main sub-micron ice grains spectral indicators are: (i) asymmetry and (ii) long ward minimum shift of the absorption band at 2.02 μm (iii) a decrease in the ratio between the band depths at 1.50 and 2.02 μm (iv) a decrease in the height of the spectral peak at 2.6 μm (v) the suppression of the Fresnel reflection peak at 3.1 μm and (vi) the decrease of the reflection peak at 5 μm relative to those at 3.6 μm.We present results from our ongoing work mapping the variation of sub-micron ice grains spectral indicators across Dione' surface using Cassini-VIMS cubes acquired in the IR range (0.8-5.1 μm). To characterize the global variations of spectral indicators across Dione' surface, we divided it into a 1°x1° grid and then averaged the band depths and peak values inside each square cell.We will investigate if there exist a correspondence with water ice abundance variations by producing water ice' absorption band depths at 1.25, 1.52 and 2.02 μm, and with surface morphology by comparing the results with ISS color maps in the ultraviolet, visible and infrared

  3. Deciphering sub-micron ice particles on Enceladus surface

    Science.gov (United States)

    Scipioni, F.; Schenk, P.; Tosi, F.; D'Aversa, E.; Clark, R.; Combe, J.-Ph.; Ore, C. M. Dalle

    2017-07-01

    The surface of Saturn's moon Enceladus is composed primarily by pure water ice. The Cassini spacecraft has observed present-day geologic activity at the moon's South Polar Region, related with the formation and feeding of Saturn's E-ring. Plumes of micron-sized particles, composed of water ice and other non-ice contaminants (e.g., CO2, NH3, CH4), erupt from four terrain's fractures named Tiger Stripes. Some of this material falls back on Enceladus' surface to form deposits that extend to the North at ∼40°W and ∼220°W, with the highest concentration found at the South Pole. In this work we analyzed VIMS-IR data to identify plumes deposits across Enceladus' surface through the variation in band depth of the main water ice spectral features. To characterize the global variation of water ice band depths across Enceladus, the entire surface was sampled with an angular resolution of 1° in both latitude and longitude, and for each angular bin we averaged the value of all spectral indices as retrieved by VIMS. The position of the plumes' deposits predicted by theoretical models display a good match with water ice band depths' maps on the trailing hemisphere, whereas they diverge significantly on the leading side. Space weathering processes acting on Enceladus' surface ionize and break up water ice molecules, resulting in the formation of particles smaller than one micron. We also mapped the spectral indices for sub-micron particles and we compared the results with the plumes deposits models. Again, a satisfactory match is observed on the trailing hemisphere only. Finally, we investigated the variation of the depth of the water ice absorption bands as a function of the phase angle. In the visible range, some terrains surrounding the Tiger Stripes show a decrease in albedo when the phase angle is smaller than 10°. This unusual effect cannot be confirmed by near infrared data, since observations with a phase angle lower than 10° are not available. For phase angle

  4. Deformation Behavior of Sub-micron and Micron Sized Alumina Particles in Compression.

    Energy Technology Data Exchange (ETDEWEB)

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay; Mook, William; Boyce, Brad; Kotula, Paul Gabriel; McKenzie, Bonnie Beth; Bufford, Daniel Charles; Hall, Aaron Christopher.

    2014-09-01

    The ability to integrate ceramics with other materials has been limited due to high temperature (>800degC) ceramic processing. Recently, researchers demonstrated a novel process , aerosol deposition (AD), to fabricate ceramic films at room temperature (RT). In this process, sub - micro n sized ceramic particles are accelerated by pressurized gas, impacted on the substrate, plastically deformed, and form a dense film under vacuum. This AD process eliminates high temperature processing thereby enabling new coatings and device integration, in which ceramics can be deposited on metals, plastics, and glass. However, k nowledge in fundamental mechanisms for ceramic particle s to deform and form a dense ceramic film is still needed and is essential in advancing this novel RT technology. In this wo rk, a combination of experimentation and atomistic simulation was used to determine the deformation behavior of sub - micron sized ceramic particle s ; this is the first fundamental step needed to explain coating formation in the AD process . High purity, singl e crystal, alpha alumina particles with nominal size s of 0.3 um and 3.0 um were examined. Particle characterization, using transmission electron microscopy (TEM ), showed that the 0.3 u m particles were relatively defect - free single crystals whereas 3.0 u m p articles were highly defective single crystals or particles contained low angle grain boundaries. Sub - micron sized Al 2 O 3 particles exhibited ductile failure in compression. In situ compression experiments showed 0.3um particles deformed plastically, fractured, and became polycrystalline. Moreover, dislocation activit y was observed within the se particles during compression . These sub - micron sized Al 2 O 3 particles exhibited large accum ulated strain (2 - 3 times those of micron - sized particles) before first fracture. I n agreement with the findings from experimentation , a tomistic simulation s of nano - Al 2 O 3 particles showed dislocation slip and

  5. Penetration of sub-micron particles into dentinal tubules using ultrasonic cavitation.

    Science.gov (United States)

    Vyas, N; Sammons, R L; Pikramenou, Z; Palin, W M; Dehghani, H; Walmsley, A D

    2017-01-01

    Functionalised silica sub-micron particles are being investigated as a method of delivering antimicrobials and remineralisation agents into dentinal tubules. However, their methods of application are not optimised, resulting in shallow penetration and aggregation. The aim of this study is to investigate the impact of cavitation occurring around ultrasonic scalers for enhancing particle penetration into dentinal tubules. Dentine slices were prepared from premolar teeth. Silica sub-micron particles were prepared in water or acetone. Cavitation from an ultrasonic scaler (Satelec P5 Newtron, Acteon, France) was applied to dentine slices immersed inside the sub-micron particle solutions. Samples were imaged with scanning electron microscopy (SEM) to assess tubule occlusion and particle penetration. Qualitative observations of SEM images showed some tubule occlusion. The particles could penetrate inside the tubules up to 60μm when there was no cavitation and up to ∼180μm when there was cavitation. The cavitation bubbles produced from an ultrasonic scaler may be used to deliver sub-micron particles into dentine. This method has the potential to deliver such particles deeper into the dentinal tubules. Cavitation from a clinical ultrasonic scaler may enhance penetration of sub-micron particles into dentinal tubules. This can aid in the development of novel methods for delivering therapeutic clinical materials for hypersensitivity relief and treatment of dentinal caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Nano-ring arrays for sub-micron particle trapping

    Science.gov (United States)

    Han, Xue; Truong, Viet Giang; Nic Chormaic, Síle

    2017-04-01

    Plasmonic tweezers based on nano-ring arrays on gold thin film are demonstrated. A cylindrical surface plasmon resonance is generated in the aperture of a nano-ring and a transmission peak results. When nano-slits are included to connect the nano-rings, the transmission peak becomes narrower. When the size of the aperture of the nano-ring is reduced, this peak is red-shifted. Both 0.5 μm and 1 μm polystyrene particles are trapped successfully by nano-ring arrays. A self-induced back-action effect is observed when a red-shifted laser beam is used. With multiple trapping sites provided by the nano-ring array, this type of plasmonic tweezers has huge potential to be integrated in lab-on-a-chip systems for life sciences research.

  7. Physics of sub-micron cosmic dust particles

    Science.gov (United States)

    Roy, N. L.

    1974-01-01

    Laboratory tests with simulated micrometeoroids to measure the heat transfer coefficient are discussed. Equations for ablation path length for electrically accelerated micrometeoroids entering a gas target are developed which yield guidelines for the laboratory measurement of the heat transfer coefficient. Test results are presented for lanthanum hexaboride (LaB sub 6) microparticles in air, argon, and oxygen targets. The tests indicate the heat transfer coefficient has a value of approximately 0.9 at 30 km/sec, and that it increases to approximately unity at 50 km/sec and above. Test results extend to over 100 km/sec. Results are also given for two types of small particle detectors. A solid state capacitor type detector was tested from 0.61 km/sec to 50 km/sec. An impact ionization type detector was tested from 1.0 to 150 km/sec using LaB sub 6 microparticles.

  8. Water ice and sub-micron ice particles on Tethys and Mimas

    Science.gov (United States)

    Scipioni, Francesca; Nordheim, Tom; Clark, Roger Nelson; D'Aversa, Emiliano; Cruikshank, Dale P.; Tosi, Federico; Schenk, Paul M.; Combe, Jean-Philippe; Dalle Ore, Cristina M.

    2017-10-01

    IntroductionWe present our ongoing work, mapping the variation of the main water ice absorption bands, and the distribution of the sub-micron particles, across Mimas and Tethys’ surfaces using Cassini-VIMS cubes acquired in the IR range (0.8-5.1 μm). We present our results in the form of maps of variation of selected spectral indicators (depth of absorption bands, reflectance peak height, spectral slopes).Data analysisVIMS acquires hyperspectral data in the 0.3-5.1 μm spectral range. We selected VIMS cubes of Tethys and Mimas in the IR range (0.8-5.1 μm). For all pixels in the selected cubes, we measured the band depths for water-ice absorptions at 1.25, 1.5 and 2.02 μm and the height of the 3.6 μm reflection peak. Moreover, we considered the spectral indictors for particles smaller than 1 µm [1]: (i) the 2 µm absorption band is asymmetric and (ii) it has the minimum shifted to longer λ (iii) the band depth ratio 1.5/2.0 µm decreases; (iv) the reflection peak at 2.6 µm decreases; (v) the Fresnel reflection peak is suppressed; (vi) the 5 µm reflectance is decreased relative to the 3.6 µm peak. To characterize the global variation of water-ice band depths, and of sub-micron particles spectral indicators, across Mimas and Tethys, we sampled the two satellites’ surfacees with a 1°x1° fixed-resolution grid and then averaged the band depths and peak values inside each square cell.3. ResultsFor both moons we find that large geologic features, such as the Odysseus and Herschel impact basins, do not correlate with water ice’s abundance variation. For Tethys, we found a quite uniform surface on both hemispheres. The only deviation from this pattern shows up on the trailing hemisphere, where we notice two north-oriented, dark areas around 225° and 315°. For Mimas, the leading and trailing hemispheres appear to be quite similar in water ice abundance, the trailing portion having water ice absorption bands lightly more suppressed than the leading side

  9. Sub-micron particle number size distribution characteristics at two urban locations in Leicester

    Science.gov (United States)

    Hama, Sarkawt M. L.; Cordell, Rebecca L.; Kos, Gerard P. A.; Weijers, E. P.; Monks, Paul S.

    2017-09-01

    The particle number size distribution (PNSD) of atmospheric particles not only provides information about sources and atmospheric processing of particles, but also plays an important role in determining regional lung dose. Owing to the importance of PNSD in understanding particulate pollution two short-term campaigns (March-June 2014) measurements of sub-micron PNSD were conducted at two urban background locations in Leicester, UK. At the first site, Leicester Automatic Urban Rural Network (AURN), the mean number concentrations of nucleation, Aitken, accumulation modes, the total particles, equivalent black carbon (eBC) mass concentrations were 2002, 3258, 1576, 6837 # cm-3, 1.7 μg m-3, respectively, and at the second site, Brookfield (BF), were 1455, 2407, 874, 4737 # cm-3, 0.77 μg m-3, respectively. The total particle number was dominated by the nucleation and Aitken modes, with both consisting of 77%, and 81% of total number concentrations at AURN and BF sites, respectively. This behaviour could be attributed to primary emissions (traffic) of ultrafine particles and the temporal evolution of mixing layer. The size distribution at the AURN site shows bimodal distribution at 22 nm with a minor peak at 70 nm. The size distribution at BF site, however, exhibits unimodal distribution at 35 nm. This study has for the first time investigated the effect of Easter holiday on PNSD in UK. The temporal variation of PNSD demonstrated a good degree of correlation with traffic-related pollutants (NOX, and eBC at both sites). The meteorological conditions, also had an impact on the PNSD and eBC at both sites. During the measurement period, the frequency of NPF events was calculated to be 13.3%, and 22.2% at AURN and BF sites, respectively. The average value of formation and growth rates of nucleation mode particles were 1.3, and 1.17 cm-3 s-1 and 7.42, and 5.3 nm h-1 at AURN, and BF sites, respectively. It can suggested that aerosol particles in Leicester originate mainly

  10. Effective Use of Focused Ion Beam (FIB) in Investigating Fundamental Mechanical Properties of Metals at the Sub-Micron Scale

    OpenAIRE

    Greer, Julia R.

    2006-01-01

    Recent advances in the 2-beam focused ion beams technology (FIB) have enabled researchers to not only perform high-precision nanolithography and micro-machining, but also to apply these novel fabrication techniques to investigating a broad range of materials' properties at the submicron and nano-scales. In our work, the FIB is utilized in manufacturing of sub-micron cylinders, or nano-pillars, as well as of TEM cross-sections to directly investigate plasticity of metals at thes...

  11. Cathepsin K-targeted sub-micron particles for regenerative repair of vascular elastic matrix.

    Science.gov (United States)

    Jennewine, Brenton; Fox, Jonathan; Ramamurthi, Anand

    2017-04-01

    regenerative elastic matrix repair in the AAA wall. Proactive screening of high risk elderly patients now enables early detection of Abdominal Aortic Aneurysms (AAAs). Current management of small, growing AAAs is limited to passive, imaging based growth monitoring. There are also no established drug-based therapeutic alternatives to surgery for AAAs, which is unsuitable for many elderly patients, and none which can achieve restore disrupted and lost elastic matrix in the AAA wall, which is essential to achieve growth arrest or regression. We seek to test the feasibility of a regenerative therapy based on localized, one time delivery of drug-releasing Sub-Micron-sized drug delivery polymer Particles (SMPs) that are also uniquely chemically functionalized on their surface to also provide them pro-elastin-regenerative & anti-matrix degradative properties, and also conjugated with antibodies targeting cathepsin K, an elastolytic enzyme that is highly overexpressed in AAA tissues; the latter serves as a modality to enable targeted binding of the SMPs to the AAA wall following intravenous infusion, or intraoartal, catheter-based delivery. Such SMPs can potentially stimulate structural repair in the AAA wall following one time infusion to delay or prevent AAA growth to rupture. The therapy can provide a non-surgical treatment option for high risk AAA patients. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. Assessment of Sub-Micron Particles by Exploiting Charge Differences with Dielectrophoresis

    Directory of Open Access Journals (Sweden)

    Maria F. Romero-Creel

    2017-08-01

    Full Text Available The analysis, separation, and enrichment of submicron particles are critical steps in many applications, ranging from bio-sensing to disease diagnostics. Microfluidic electrokinetic techniques, such as dielectrophoresis (DEP have proved to be excellent platforms for assessment of submicron particles. DEP is the motion of polarizable particles under the presence of a non-uniform electric field. In this work, the polarization and dielectrophoretic behavior of polystyrene particles with diameters ranging for 100 nm to 1 μm were studied employing microchannels for insulator based DEP (iDEP and low frequency (<1000 Hz AC and DC electric potentials. In particular, the effects of particle surface charge, in terms of magnitude and type of functionalization, were examined. It was found that the magnitude of particle surface charge has a significant impact on the polarization and dielectrophoretic response of the particles, allowing for successful particle assessment. Traditionally, charge differences are exploited employing electrophoretic techniques and particle separation is achieved by differential migration. The present study demonstrates that differences in the particle’s surface charge can also be exploited by means of iDEP; and that distinct types of nanoparticles can be identified by their polarization and dielectrophoretic behavior. These findings open the possibility for iDEP to be employed as a technique for the analysis of submicron biological particles, where subtle differences in surface charge could allow for rapid particle identification and separation.

  13. Preparation of chitosan-TPP sub-micron particles: Critical evaluation and derived recommendations.

    Science.gov (United States)

    Rázga, Filip; Vnuková, Dominika; Némethová, Veronika; Mazancová, Petra; Lacík, Igor

    2016-10-20

    The controlled preparation of chitosan particles is far from being trivial due to a considerable number of experimental parameters. For chitosan-tripolyphosphate (TPP) particles we evaluate the impact of chemical (type of chitosan, concentration, chitosan to TPP ratio, pH, ionic strength) and process factors (dialysis, stirring rate, rate of TPP addition, temperature, needle diameter) on the size and colloidal stability. The particles were prepared at pH=6.0 at which chitosan adopts the coiled conformation that is discussed as the dominant factor in controlling the stoichiometry of crosslinking reaction shifted towards TPP. These conditions result in identical particle size around 400nm and zeta potential around 22mV. The colloidal stability evaluated 24 hours after preparation depends on the amount of TPP during crosslinking. Under the same conditions, the colloidal stability up to 1 month is demonstrated. Several recommendations are provided to increase the control over formation of chitosan-TPP particles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Bragg diffraction from sub-micron particles isolated by optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yuan, E-mail: ygao0709@anl.gov; Harder, Ross; Southworth, Stephen; Guest, Jeffrey; Ocola, Leonidas; Young, Linda [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Scherer, Norbert; Yan, Zijie [Department of Chemistry, University of Chicago, Chicago, IL 60637 (United States); Pelton, Matthew [Department of Physics, University of Maryland, Baltimore County, MD 21250 (United States)

    2016-07-27

    We describe an apparatus using dynamic holographic optical tweezers which is capable of trapping and aligning a single micron scale anisotropic ZnO particle for x-ray Bragg diffraction experiments. The optical tweezers demonstrate enough stability to perform coherent x-ray diffraction imaging.

  15. A Novel Step-Doping Fully-Depleted Silicon-on-Insulator Metal-Oxide-Semiconductor Field-Effect Transistor for Reliable Deep Sub-micron Devices

    Science.gov (United States)

    Elahipanah, Hossein; Orouji, Ali A.

    2009-11-01

    For first time, we report a novel deep sub-micron fully-depleted silicon-on-insulator metal-oxide-semiconductor field-effect-transistor (FD SOI MOSFET) where the channel layer consists of two sections with a step doping (SD) region in order to increase performance and reliability of the device. This new structure that called SD FD SOI structure (SDFD-SOI MOSFET), were used for reaching suitable threshold voltage upon device scaling and reliability improvement. We demonstrate that the electric field was modified in the channel and common peak near the source junction have been reduced in the SDFD-SOI structure. The device demonstrates large enhancements in performance areas such as current drive capability, output resistance, hot-carrier reliability and threshold voltage roll-off. It was found that the device performance is very much dependent upon the SD region parameters. Simulation results show that the proposed structure improved on/off current ratio, and saturated output characteristics compared with conventional SOI structure (C-SOI MOSFET). Also, it was shown that substrate current of SDFD-SOI MOSFET is much lower than the C-SOI MOSFET which presented the lower hot-carrier degradation in proposed MOSFET. Results show that the most short-channel problems in very large scale integrated circuits (VLSI) could be solved and the proposed SDFD-SOI MOSFETs can work very well in deep sub-micron and nanoscale regime.

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

    Directory of Open Access Journals (Sweden)

    M. Cusack

    2013-05-01

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

  17. The heterogeneous reaction of hydroxyl radicals with sub-micron squalane particles: a model system for understanding the oxidative aging of ambient aerosols

    Science.gov (United States)

    Smith, J. D.; Kroll, J. H.; Cappa, C. D.; Che, D. L.; Liu, C. L.; Ahmed, M.; Leone, S. R.; Worsnop, D. R.; Wilson, K. R.

    2009-05-01

    The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3±0.07 at an average OH concentration of ~1×1010 molecules cm-3. Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle-phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle-phase organic matter in the troposphere.

  18. The heterogeneous reaction of hydroxyl radicals with sub-micron squalane particles: a model system for understanding the oxidative aging of ambient aerosols

    Directory of Open Access Journals (Sweden)

    J. D. Smith

    2009-05-01

    Full Text Available The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3±0.07 at an average OH concentration of ~1×1010 molecules cm−3. Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle-phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle-phase organic matter in the troposphere.

  19. Sub-micron particle behaviour and capture at an immuno-sensor surface in an ultrasonic standing wave.

    Science.gov (United States)

    Kuznetsova, Larisa A; Martin, Stacey P; Coakley, W Terence

    2005-12-15

    The capture of 200 nm biotinylated latex beads from suspensions of concentration 10(7) to 2.5 x 10(8) particle/ml on an immuno-coated surface of the acoustic reflector in an ultrasound standing wave (USW) resonator has been studied while the acoustic pathlength was less than one half wavelength (lambda/2). The particles were delivered to the reflector's surface by acoustically induced flow. The capture dependencies on suspension concentration, duration of experiments and acoustic pressure have been established at 1.09, 1.46 and 1.75 MHz. Five-fold capture increase has been obtained at 1.75 MHz in comparison to the control (no ultrasound) situation. The contrasting behaviours of 1, 0.5 and 0.2 mum fluorescent latex beads in a lambda/4 USW resonator at 1.46 MHz have been characterized. The particle movements were observed with an epi-fluorescent microscope and the velocities of the particles were measured by particle image velocimetry (PIV). The experiments showed that whereas the trajectories of 1 mum particles were mainly affected by the direct radiation force, 0.5 mum particles were influenced both by the radiation force and acoustic streaming. The 0.2 mum latex beads followed acoustic streaming in the chamber and were not detectably affected by the radiation force. The streaming-associated behaviour of the 200 nm particles has implications for enhanced immunocapture of viruses and macromolecules (both of which are also too small to experience significant acoustic radiation force).

  20. Influence of biomass burning on mixing state of sub-micron aerosol particles in the North China Plain

    Science.gov (United States)

    Kecorius, Simonas; Ma, Nan; Teich, Monique; van Pinxteren, Dominik; Zhang, Shenglan; Gröβ, Johannes; Spindler, Gerald; Müller, Konrad; Iinuma, Yoshiteru; Hu, Min; Herrmann, Hartmut; Wiedensohler, Alfred

    2017-09-01

    Particulate emissions from crop residue burning decrease the air quality as well as influence aerosol radiative properties on a regional scale. The North China Plain (NCP) is known for the large scale biomass burning (BB) of field residues, which often results in heavy haze pollution episodes across the region. We have been able to capture a unique BB episode during the international CAREBeijing-NCP intensive field campaign in Wangdu in the NCP (38.6°N, 115.2°E) from June to July 2014. It was found that aerosol particles originating from this BB event showed a significantly different mixing state compared with clean and non-BB pollution episodes. BB originated particles showed a narrower probability density function (PDF) of shrink factor (SF). And the maximum was found at shrink factor of 0.6, which is higher than in other episodes. The non-volatile particle number fraction during the BB episode decreased to 3% and was the lowest measured value compared to all other predefined episodes. To evaluate the influence of particle mixing state on aerosol single scattering albedo (SSA), SSA at different RHs was simulated using the measured aerosol physical-chemical properties. The differences between the calculated SSA for biomass burning, clean and pollution episodes are significant, meaning that the variation of SSA in different pollution conditions needs to be considered in the evaluation of aerosol direct radiative effects in the NCP. And the calculated SSA was found to be quite sensitive on the mixing state of BC, especially at low-RH condition. The simulated SSA was also compared with the measured values. For all the three predefined episodes, the measured SSA are very close to the calculated ones with assumed mixing states of homogeneously internal and core-shell internal mixing, indicating that both of the conception models are appropriate for the calculation of ambient SSA in the NCP.

  1. Hygroscopicity of Chemically Aged, sub-micron Squalane Particles: On the Role of Size and Composition towards the Hygroscopicity Parameter κ

    Science.gov (United States)

    Harmon, C. W.; Smith, J. D.; Che, D. L.; Leone, S. R.; Wilson, K. R.

    2010-12-01

    Measurements presented herein explore cloud condensation nuclei (CCN) activity of sub-micron squalane particles chemically aged by hydroxyl radicals as a function of size and OH exposure. As squalane particles are exposed to OH radicals, size-selected 100, 150, and 200 nm particles monotically decrease in size with increasing OH exposure. Concurrently, their CCN derived hygroscopicity parameter values, κ, increase with OH exposure until saturating at 0.165 in the 100 nm data set, 0.140 in the 150 nm data set, and reach a maximum value of 0.075 in the 200 nm data set at the highest level of OH exposure. The critical super-saturation relative humidity (RH) at which CCN activity is achieved decreases initially with increasing OH exposure and then increases with OH exposure, most notably for the 100 nm data set and weakly with the 150 nm data set. Chemically aged squalane particles from the 200 nm data set show a monotonic decrease in critical super-saturation RH with all values of increasing OH exposure between 0.1-2.5 × 10^13 s molec./cc. The measured O:C ratios of 160 nm chemically aged squalane particles, which were reported previously, are compared to κ values by the CCN derived relationship reported in literature: κ = 0.30*O:C and reasonable agreement is attained in the size-selected 150 nm data set. These values are also compared with the hygroscopic growth factor derived relationship in literature: κ = 0.49*(O:C -0.25) and reasonable agreement is attained at O:C > 0.35.

  2. Transglutaminase-induced or citric acid-mediated cross-linking of whey proteins to tune the characteristics of subsequently desolvated sub-micron and nano-scaled particles.

    Science.gov (United States)

    Bagheri, Leila; Yarmand, Mohammadsaeed; Madadlou, Ashkan; Mousavi, Mohammad E

    2014-01-01

    Whey proteins were inter-connected either by the enzyme transglutaminase or citric acid and then desolvated with ethanol to generate particles. Both samples comprised of sub-micron (>300 nm) and nano-scaled (~100 nm) particles based on the hydrodynamic size measurements. Enzyme-induced cross-linking of proteins yielded more monodisperse particles and decreased the mean size of the major (nano-scaled) fraction of particles. Scanning electron microscopy images revealed a spherical morphology for all samples with mean sizes of particles from enzymatically cross-linked proteins. The mediating role of citric acid in bridging the proteins was confirmed by Fourier transform infrared spectroscopy. Differential scanning calorimetry indicated that pre-heating of protein solution before cross-linking and desolvation denatured the proteins entirely. In vitro degradation of whey protein particles in a simulated gastric fluid demonstrated that cross-linking of whey proteins before desolvation stage enhanced significantly the digestion stability of particles.

  3. Separating the signal from the noise: Expanding flow cytometry into the sub-micron range.

    Science.gov (United States)

    Cytometry Part A Special Section: Separating the signal from the noise: Expanding flow cytometry into the sub-micron range. The current Cytometry Part A Special Section presents three studies that utilize cytometers to study sub-micron particles. The three studies involve the 1...

  4. Synthesis, characterization and electrochemical characterization of lead selenide sub-micron particles capped with a benzoate ligand and prepared at different temperatures

    Science.gov (United States)

    Rodríguez-Rodríguez, Weyshla A.; Colón, Jadiel; Guzmán, Roger; Rivera, Harry; Santiago-Berríos, Mitk'El B.

    2014-09-01

    Semiconductor materials offer several potential benefits as active elements in the development of harvesting-energy conversion technologies. In particular, lead selenide (PbSe) semiconductors have been used and proposed to design solar energy harvesting devices, IR sensors, FET devices, etc. Lead salts have drawn particular attention from the applied and fundamental research communities due to their exceptionally strong quantum confinement effects. Several syntheses of PbSe have been proposed using long chain surfactants to allow the formation of particles and nanoparticles. Here we present a synthesis using benzoic acid as the capping ligand in ambient atmosphere. Although the particles are not in nanometric size, we compare the crystal structure (using x-ray powder diffraction data), the near infrared and mid-infrared absorption properties of PbSe using oleic acid as the capping ligand with PbSe using benzoic acid as the capping ligand. The new synthetized particles were shown to have similar crystal structure and absorb light in the near infrared region at 1410 nm. We also performed cyclic voltammetry of these particles drop-casted in the surface of a glassy carbon electrode. The particles showed electrochemical behavior with an oxidation peak near (-402 ± 5 mV) versus Ag/AgCl reference electrode. The particles seem to form a polymeric film at the surface of a glassy carbon electrode.

  5. The surface characterisation and comparison of two potential sub-micron, sugar bulking excipients for use in low-dose, suspension formulations in metered dose inhalers.

    Science.gov (United States)

    James, Jeff; Crean, Barry; Davies, Martyn; Toon, Richard; Jinks, Phil; Roberts, Clive J

    2008-09-01

    This study compares the surface characteristics and surface energetics of two potential bulking excipients, anhydrous sub-micron alpha-lactose and sub-micron sucrose, for use with low-dose, suspension formulations in pressurised metered dose inhalers (pMDIs). Both sub-micron bulking excipients are processed from parent materials (alpha-lactose monohydrate/alpha-lactose monohydrate and silk grade sucrose, respectively) so the surface characteristics of each material were determined and compared. Additionally, the surface energetics and adhesive interactions between each sub-micron bulking excipient and some chosen active pharmaceutical ingredients (APIs) used in pMDI formulations were also determined. From this data, it was possible to predict the potential degree of interaction between the APIs and each sub-micron bulking excipient, thus determining suitable API-excipient combinations for pMDI formulation optimisation. Salmon calcitonin was also investigated as a potential API due to the current interest in, and the potential low-dose requirements for, the pulmonary delivery of proteins. The size and morphology of each sub-micron excipient (and parent materials) were determined using scanning electron microscopy (SEM) and the crystalline nature of each sub-micron excipient and parent material was assessed using X-ray diffraction (XRD). The surface chemistry of each sub-micron excipient was analysed using X-ray photoelectron spectroscopy (XPS). The surface energies of each sub-micron excipient, along with their respective parent materials and any intermediates, were determined using two techniques. The surface energies of these materials were determined via (a) single particle adhesive interactions using atomic force microscopy (AFM) and (b) 'bulk' material surface interactions using contact angle measurements (CA). From the CA data, it was possible to calculate the theoretical work of adhesion values for each API-excipient interaction using the surface component

  6. Spectroscopic and magnetic properties of neodymium doped in GdPO{sub 4} sub-micron-stars prepared by solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, G.A., E-mail: ajith@gakumar.net [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, 78249 (United States); Balli, Nicolas R. [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, 78249 (United States); Kailasnath, M. [International School of Photonics, Cochin University of Science and Technology, Kochi, 682022 (India); Mimun, L. Christopher [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, 78249 (United States); Dannangoda, Chamath; Martirosyan, Karen S. [University of Texas at Rio Grande Valley, Brownsville, TX, 78520 (United States); Santhosh, C. [Department of Atomic and Molecular Spectroscopy, Manipal University, Manipal, 576104 (India); Sardar, Dhiraj K. [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, 78249 (United States)

    2016-07-05

    Neodymium-doped gadolinium orthophosphate (GdPO{sub 4}:Nd{sup 3+}) luminomagnetic sub-micron-stars were prepared by solvothermal method using metal nitrates and phosphoric acid. Monoclinic star shaped in six lobed sub-micron-stars with 600 nm length is obtained with uniform particle size distribution. After heat-treatment at 800 °C for 1 h in air, the stars separate into isolated petal shaped particles and show characteristic emission bands of Nd{sup 3+} with the strongest emission at 1064 nm. The emission intensities and fluorescence decay times are dependent on the Nd{sup 3+} concentration with the highest emission intensity and longest fluorescence decay time of 311 μs at 1064 nm with 0.5 mol% Nd{sup 3+}. Under 808 nm excitation with 12 W/cm{sup 2} power density a quantum yield of 9% was obtained for the 1.0 mol% Nd{sup 3+}. The presence of paramagnetic Gd{sup 3+} gives magnetic properties to the phosphor with a calculated magnetic moment of 1510 and 107,965 Bohr magneton at 300 and 5 K, respectively. - Highlights: • Star shaped Nd doped GdPO{sub 4} sub-micron phosphor particles are prepared for the first time. • Particles show both optical and magnetic properties. • Under 808 nm excitation near infrared emission was observed at 1064 nm with 9% quantum yield. • Magnetic moment of the particle was 1510 and 107,965 Bohr magneton at 300 and 5 K, respectively.

  7. Scanning SQUID susceptometers with sub-micron spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A. [Department of Applied Physics, Stanford University, Stanford, California 94305-4045 (United States); Paulius, Lisa [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Spanton, Eric M. [Department of Physics, Stanford University, Stanford, California 94305-4045 (United States); Schiessl, Daniel [Attocube Systems AG, Königinstraße 11A, 80539 Munich (Germany); Jermain, Colin L.; Gibbons, Jonathan [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Fung, Y.-K.K.; Gibson, Gerald W. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Huber, Martin E. [Department of Physics, University of Colorado Denver, Denver, Colorado 80217-3364 (United States); Ralph, Daniel C. [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States); Ketchen, Mark B. [OcteVue, Hadley, Massachusetts 01035 (United States)

    2016-09-15

    Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ{sub 0}/Hz{sup 1/2}. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

  8. Sub-micron Cu/SSZ-13: Synthesis and application as selective catalytic reduction (SCR) catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Prodinger, Sebastian; Derewinski, Miroslaw A.; Wang, Yilin; Washton, Nancy M.; Walter, Eric D.; Szanyi, János; Gao, Feng; Wang, Yong; Peden, Charles H. F.

    2017-02-01

    For the first time, sub-micron Cu/SSZ-13, obtained by modifying an existing synthesis procedure, was shown to be an effective and stable catalyst for selective catalytic reduction reactions, such as NO reduction. Characterization of the materials with X-ray diffraction, N2-physisorption and 27Al MAS NMR shows that hydrothermal aging, simulating SCR reaction conditions, is more destructive in respect to dealumination for smaller particles prior to Cu-exchange. However, the catalytic performance and hydrothermal stability for Cu/SSZ-13 is independent of the particle size. In particular, the stability of tetrahedral framework Al is improved in the sub-micron Cu/SSZ-13 catalysts of comparable Cu loading. This indicates that variations in the Al distribution for different SSZ-13 synthesis procedures have a more critical influence on stabilizing isolated Cu-ions during harsh hydrothermal aging than the particle size. This study is of high interest for applications in vehicular DeNOx technologies where high loadings of active species on wash coats can be achieved by using sub-micron Cu/SSZ-13. The authors would like to thank B. W. Arey and J. J. Ditto for performing electron microscope imaging. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. S. P and M. A. D also acknowledge support by the Materials Synthesis and Simulation Across Scales (MS3 Initiative) conducted under the Laboratory Directed Research & Development Program at PNNL. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

  9. Impact-disrupted gunshot residue: A sub-micron analysis using a novel collection protocol

    Directory of Open Access Journals (Sweden)

    V. Spathis

    2017-06-01

    Full Text Available The analysis of gunshot residue (GSR has played an integral role within the legal system in relation to shooting cases. With a characteristic elemental composition of lead, antimony, barium, and a typically discriminative spheroidal morphology, the presence and distribution of GSR can aid in firearm investigations. In this experiment, three shots of low velocity rim-fire ammunition were fired over polished silicon collection substrates placed at six intervals over a 100 cm range. The samples were analysed using a Field Emission Gun Scanning Electron Microscope (FEG-SEM in conjunction with an X-flash Energy Dispersive X-ray (EDX detector, allowing for GSR particle analyses of composition and structure at the sub-micron level. The results of this experiment indicate that although classic spheroidal particles are present consistently throughout the entire range of samples their sizes vary significantly, and at certain distances from the firearm particles with an irregular morphology were discerned, forming “impact-disrupted” GSR particles, henceforth colloquially referred to as “splats”. Upon further analysis, trends with regards to the formation of these splat particles were distinguished. An increase in splat frequency was observed starting at 10 cm from the firearm, with 147 mm−2 splat density, reaching a maximal flux at 40 cm (451 mm−2, followed by a gradual decrease to the maximum range sampled. Moreover, the structural morphology of the splats changes throughout the sampling range. At the distances closest to the firearm, molten-looking particles were formed, demonstrating the metallic residues were in a liquid state when their flight path was disrupted. However, at increased distances-primarily where the discharge plume was at maximum dispersion and moving away from the firearm, the residues have had time to cool in-fight resulting in semi-congealed and solid particles that subsequently disrupted upon impact, forming more

  10. Acoustic Emission Patterns and the Transition to Ductility in Sub-Micron Scale Laboratory Earthquakes

    Science.gov (United States)

    Ghaffari, H.; Xia, K.; Young, R.

    2013-12-01

    We report observation of a transition from the brittle to ductile regime in precursor events from different rock materials (Granite, Sandstone, Basalt, and Gypsum) and Polymers (PMMA, PTFE and CR-39). Acoustic emission patterns associated with sub-micron scale laboratory earthquakes are mapped into network parameter spaces (functional damage networks). The sub-classes hold nearly constant timescales, indicating dependency of the sub-phases on the mechanism governing the previous evolutionary phase, i.e., deformation and failure of asperities. Based on our findings, we propose that the signature of the non-linear elastic zone around a crack tip is mapped into the details of the evolutionary phases, supporting the formation of a strongly weak zone in the vicinity of crack tips. Moreover, we recognize sub-micron to micron ruptures with signatures of 'stiffening' in the deformation phase of acoustic-waveforms. We propose that the latter rupture fronts carry critical rupture extensions, including possible dislocations faster than the shear wave speed. Using 'template super-shear waveforms' and their network characteristics, we show that the acoustic emission signals are possible super-shear or intersonic events. Ref. [1] Ghaffari, H. O., and R. P. Young. "Acoustic-Friction Networks and the Evolution of Precursor Rupture Fronts in Laboratory Earthquakes." Nature Scientific reports 3 (2013). [2] Xia, Kaiwen, Ares J. Rosakis, and Hiroo Kanamori. "Laboratory earthquakes: The sub-Rayleigh-to-supershear rupture transition." Science 303.5665 (2004): 1859-1861. [3] Mello, M., et al. "Identifying the unique ground motion signatures of supershear earthquakes: Theory and experiments." Tectonophysics 493.3 (2010): 297-326. [4] Gumbsch, Peter, and Huajian Gao. "Dislocations faster than the speed of sound." Science 283.5404 (1999): 965-968. [5] Livne, Ariel, et al. "The near-tip fields of fast cracks." Science 327.5971 (2010): 1359-1363. [6] Rycroft, Chris H., and Eran Bouchbinder

  11. Sub-micron Hard X-ray Fluorescence Imaging of Synthetic Elements

    Science.gov (United States)

    Jensen, Mark P.; Aryal, Baikuntha P.; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E.

    2013-01-01

    Synchrotron-based X-ray fluorescence microscopy (SXFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurement such as μ-XANES (X-ray absorption near edge structure). We have used SXFM to image and simultaneously quantify the transuranic element plutonium at the L3 or L2 edge as well as lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope 242Pu. Elemental maps reveal that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions for an average 202 μm2 cell is 1.4 fg Pu/cell or 2.9 × 10−20 moles Pu/μm2, which is similar to the detection limit of K-edge SXFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its Lα X-ray emission. PMID:22444530

  12. Interaction of Burning Metal Particles

    Science.gov (United States)

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

    1999-01-01

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

  13. Analysis and Design of Monolithic Inductors in Sub-micron CMOS

    DEFF Research Database (Denmark)

    Fallesen, Carsten; Jørgensen, Allan

    1997-01-01

    In the last few years the CMOS processes have gone into deep sub-micron channel lengths. This means that it is now possible to make GHz applications in CMOS. In analog GHz applications it is often necessary to have access to inductors. This report describes the development of a physical model of ...

  14. Sub-micron-sized delafossite CuCrO2 with different morphologies ...

    Indian Academy of Sciences (India)

    40, No. 1, February 2017, pp. 195–199. c Indian Academy of Sciences. DOI 10.1007/s12034-016-1340-6. Sub-micron-sized delafossite CuCrO2 with different morphologies synthesized by nitrate–citric acid sol–gel route. SATISH BOLLOJU1 and RADHAKRISHNAN SRINIVASAN1,2,∗. 1Department of Chemistry, BITS Pilani ...

  15. Directed assembly of conducting polymers on sub-micron templates by electrical fields

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jia; Wei, Ming [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Busnaina, Ahmed [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, Northeastern University, Boston, MA 02115 (United States); Barry, Carol [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Mead, Joey, E-mail: Joey_Mead@uml.edu [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, University of Massachusetts Lowell, Lowell, MA 01854 (United States)

    2013-02-20

    Highlights: Black-Right-Pointing-Pointer Nanoscale patterns with dimensions of assembled PANi down to 100 nm were fabricated. Black-Right-Pointing-Pointer We use electrophoretic and dielectrophoretic assembly to deposit PANi. Black-Right-Pointing-Pointer Electrophoretic and dielectrophoretic assembly of PANi finished in less than 1 min. Black-Right-Pointing-Pointer Effect of process parameters on assembly of PANi onto nanoscale pattern was studied. Black-Right-Pointing-Pointer The assembled PANi can be transferred to other flexible substrates. - Abstract: Patterning of conducting polymer into sub-micron patterns over large areas at high rate and low cost is significant for commercial manufacturing of novel devices. Electrophoretic and dielectrophoretic assembly provide an easily scaled approach with high fabrication rates. In this work, electrophoretic and dielectrophoretic assembly were used to assemble polyaniline (PANi) into multiscale sub-micron size patterns in less than 1 min. The process was controlled by assembly time, amplitude, and frequency of the electric field. Dielectrophoretic assembly is preferable for manufacturing as it reduces damage to the templates used to control the assembly. Using this method, sub-micron patterns with dimensions of the assembled PANi down to 100 nm were fabricated over large areas in short times. The assembled PANi was further transferred to other flexible polymer substrates by a thermoforming process, providing a fast, easily controlled and promising approach for fabrication of nanoscale devices.

  16. Laser smoothing of sub-micron grooves in hydroxyl-rich fused silica

    Energy Technology Data Exchange (ETDEWEB)

    Shen Nan [Lawrence Livermore National Laboratory, 7000 East Avenue, L-491, Livermore, CA 94550-9234 (United States); Matthews, Manyalibo J., E-mail: ibo@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Avenue, L-491, Livermore, CA 94550-9234 (United States); Fair, James E.; Britten, Jerald A.; Nguyen, Hoang T.; Cooke, Diane; Elhadj, Selim; Yang, Steven T. [Lawrence Livermore National Laboratory, 7000 East Avenue, L-491, Livermore, CA 94550-9234 (United States)

    2010-04-01

    Nano- to micrometer-sized surface defects on UV-grade fused silica surfaces are known to be effectively smoothed through the use of high-temperature localized CO{sub 2} laser heating, thereby enhancing optical properties. However, the details of the mass transport and the effect of hydroxyl content on the laser smoothing of defective silica at sub-micron length scales are still not completely understood. In this study, we examine the morphological evolution of sub-micron, dry-etched periodic surface structures on type II and type III SiO{sub 2} substrates under 10.6 {mu}m CO{sub 2} laser irradiation using atomic force microscopy (AFM). In situ thermal imaging was used to map the transient temperature field across the heated region, allowing assessment of the T-dependent mass transport mechanisms under different laser-heating conditions. Computational fluid dynamics simulations correlated well with experimental results, and showed that for large effective capillary numbers (N{sub c} > 2), surface diffusion is negligible and smoothing is dictated by capillary action, despite the relatively small spatial scales studied here. Extracted viscosity values over 1700-2000 K were higher than the predicted bulk values, but were consistent with the surface depletion of OH groups, which was confirmed using confocal Raman microscopy.

  17. Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes

    Energy Technology Data Exchange (ETDEWEB)

    Famiano, M.A.

    1997-07-07

    A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time ({approximately}1 {micro}s to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, {sup 137}Cs gamma rays, and electrons from a {sup 90}Sr/{sup 90}Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired.

  18. The fabrication of integrated carbon pipes with sub-micron diameters

    Science.gov (United States)

    Kim, B. M.; Murray, T.; Bau, H. H.

    2005-08-01

    A method for fabricating integrated carbon pipes (nanopipettes) of sub-micron diameters and tens of microns in length is demonstrated. The carbon pipes are formed from a template consisting of the tip of a pulled alumino-silicate glass capillary coated with carbon deposited from a vapour phase. This method renders carbon nanopipettes without the need for ex situ assembly and facilitates parallel production of multiple carbon-pipe devices. An electric-field-driven transfer of ions in a KCl solution through the integrated carbon pipes exhibits nonlinear current-voltage (I-V) curves, markedly different from the Ohmic I-V curves observed in glass pipettes under similar conditions. The filling of the nanopipette with fluorescent suspension is also demonstrated.

  19. Dynamics of Dissolved Organic Matter and Microbes in Seawater through Sub-Micron Particle Size Analyses

    Digital Repository Service at National Institute of Oceanography (India)

    Goes, J.I.; Balch, W.M.; Vaughn, J.M.; Gomes, H.R.

    processes responsible for the dynamics of DOM rely on monitoring the consumption and breakdown of specific compounds of phytoplankton origin, generally, through the use of labeled precursors and substrates (Kirchman et al., 1991; Fry et al., 1996; Rich et al... attempts to determine the molecular weight or size spectrum of DOM using size exclusion chromatography, but these have generally proven unsatisfactory (Beckett et al., 1987). One reason is that DOM is exposed to high shear stresses during separation...

  20. Metallic nano-particles for trapping light.

    Science.gov (United States)

    Tang, Yongan; Vlahovic, Branislav

    2013-02-07

    We study metallic nano-particles for light trapping by investigating the optical absorption efficiency of the hydrogenated amorphous silicon thin film with and without metallic nano-particles on its top. The size and shape of these nano-particles are investigated as to their roles of light trapping: scattering light to the absorption medium and converting light to surface plasmons. The optical absorption enhancement in the red light region (e.g., 650nm) due to the light trapping of the metallic nano-particles is observed when a layer of metallic nano-particle array has certain structures. The investigation of the light with incident angles shows the importance of the coupling efficiency of light to surface plasmons in the metallic nano-particle light trapping. PACS: 73.20.Mf, 42.25.s, 88.40.hj.

  1. A Nordic project on high speed low power design in sub-micron CMOS technology for mobile phones

    DEFF Research Database (Denmark)

    Olesen, Ole

    This paper is a survey paper presenting the Nordic CONFRONT project and reporting some results from the group at CIE/DTU, Denmark. The objective of the project is to demonstrate the feasibility of sub-micron CMOS for the realisation of RF front-end circuits operating at frequencies in the 1...

  2. Large area sub-micron chemical imaging of magnesium in sea urchin teeth.

    Science.gov (United States)

    Masic, Admir; Weaver, James C

    2015-03-01

    The heterogeneous and site-specific incorporation of inorganic ions can profoundly influence the local mechanical properties of damage tolerant biological composites. Using the sea urchin tooth as a research model, we describe a multi-technique approach to spatially map the distribution of magnesium in this complex multiphase system. Through the combined use of 16-bit backscattered scanning electron microscopy, multi-channel energy dispersive spectroscopy elemental mapping, and diffraction-limited confocal Raman spectroscopy, we demonstrate a new set of high throughput, multi-spectral, high resolution methods for the large scale characterization of mineralized biological materials. In addition, instrument hardware and data collection protocols can be modified such that several of these measurements can be performed on irregularly shaped samples with complex surface geometries and without the need for extensive sample preparation. Using these approaches, in conjunction with whole animal micro-computed tomography studies, we have been able to spatially resolve micron and sub-micron structural features across macroscopic length scales on entire urchin tooth cross-sections and correlate these complex morphological features with local variability in elemental composition. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Chemical Mapping of Proterozoic Organic Matter at Sub-Micron Spatial Resolution

    Science.gov (United States)

    Oehler, Dorothy Z.; Robert, Francois; Mostefaoui, Smail; Meibom, Anders; Selo, Madeleine; McKay, David S.

    2006-01-01

    We have used a NanoSIMS ion microprobe to map sub-micron-scale distributions of carbon, nitrogen, sulfur, silicon, and oxygen in organic microfossils and laminae from the approximately 0.85 Ga Bitter Springs Formation of Australia. The data provide clues about the original chemistry of the microfossils, the silicification process, and biosignatures of specific microorganisms and microbial communities. Chemical maps of fossil unicells and filaments reveal distinct wall-and sheath-like structures enriched in C, N and S, consistent with their accepted biological origin. Surprisingly, organic laminae, previously considered to be amorphous, also exhibit filamentous and apparently compressed spheroidal structures defined by strong enrichments in C, N and S. By analogy to data from the well-preserved microfossils, these structures are interpreted as being of biological origin, most likely representing densely packed remnants of microbial mats. Because the preponderance of organic matter in Precambrian sediments is similarly "amorphous," our findings open a large body of generally neglected material to in situ structural, chemical, and isotopic study. Our results also offer new criteria for assessing biogenicity of problematic kerogenous materials and thus can be applied to assessments of poorly preserved or fragmentary organic residues in early Archean sediments and any that might occur in meteorites or other extraterrestrial samples.

  4. Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

    Science.gov (United States)

    Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

    2015-09-28

    The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

  5. Laser smoothing of sub-micron grooves in hydroxyl-rich fused silica

    Energy Technology Data Exchange (ETDEWEB)

    Shen, N; Matthews, M J; Fair, J E; Britten, J A; Nguyen, H T; Cooke, D; Elhadj, S; Yang, S T

    2009-10-30

    Nano- to micrometer-sized surface defects on UV-grade fused silica surfaces are known to be effectively smoothed through the use of high-temperature localized CO{sub 2} laser heating, thereby enhancing optical properties. However, the details of the mass transport and the effect of hydroxyl content on the laser smoothing of defective silica at submicron length scales is still not completely understood. In this study, we examine the morphological evolution of sub-micron, dry-etched periodic surface structures on type II and type III SiO{sub 2} substrates under 10.6 {micro}m CO{sub 2} laser irradiation using atomic force microscopy (AFM). In-situ thermal imaging was used to map the transient temperature field across the heated region, allowing assessment of the T-dependent mass transport mechanisms under different laser-heating conditions. Computational fluid dynamics simulations correlated well with experimental results, and showed that for large effective capillary numbers (N{sub c} > 2), surface diffusion is negligible and smoothing is dictated by capillary action, despite the relatively small spatial scales studied here. Extracted viscosity values over 1700-2000K were higher than the predicted bulk values, but were consistent with the surface depletion of OH groups, which was confirmed using confocal Raman microscopy.

  6. Ultrathin oxides for the SCM analysis of sub-micron doping profiles

    Energy Technology Data Exchange (ETDEWEB)

    Ciampolini, Lorenzo; Bertin, F.; Hartmann, J.M.; Rochat, N.; Holliger, Ph.; Laugier, F.; Chabli, A

    2003-09-15

    Attenuated total reflection (ATR) spectroscopy and spectroscopic ellipsometry (SE) have been used to characterize oxides used for the scanning capacitance microscopy (SCM) technique. SCM has been used to study boron and phosphorous doped Si test structures epitaxially grown on (100) Si substrates. SCM samples have one-dimensional (1D) doping profiles with sub-micron features, with staircase-like steps in the unipolar sample and a smoother profile in the bipolar sample, as obtained by secondary ion mass spectrometry (SIMS) profiling. Cross-sectional SCM results obtained on samples oxidized by the standard low-temperature UV-ozone method are presented, discussed and compared to results obtained on cleaved samples oxidized by a simple exposure to air. The results show that the native oxide covering a (110) cleaved section may yield SCM images of sufficient quality, with no contrast reversal on a wide range of doping levels, as well as observed on sections prepared with the UV-ozone technique. However, the long-term stability of the SCM signal on native oxides is poor, and UV-ozone oxidation can be used to recover a valid SCM signal. Realistic ultrathin oxide thickness data obtained by SE on (110) substrates are presented together with ATR results, which confirm the superior quality of UV-ozone oxides with respect to other kinds of oxides.

  7. Sub-micron opto-chemical probes for studying living neurons

    Science.gov (United States)

    Hossein-Zadeh, M.; Delgado, J.; Schweizer, F.; Lieberman, R.

    2017-02-01

    We have fabricated sub-micron opto-chemical probes for pH, oxygen and calcium monitoring and demonstrated their application in intracellular and extracellular monitoring of neurons (cortical neuronal cultures and acute hippocampal slices). Using these probes, we have measured extracellular pH in the stratum radiatum of the CA1 region of mouse hippocampus upon stimulation of presynaptic Schaffer collateral axons. Synaptic transmission was monitored using standard electrophysiological techniques. We find that the local pH transiently changes in response to synaptic stimulation. In addition, the geometry of the functionalized region on the probe combined with high sensitivity imaging enables simultaneous monitoring of spatially adjacent but distinct compartments. As proof of concept we impaled cultured neurons with the probe measured calcium and pH inside as well as directly outside of neurons as we changed the pH and calcium concentration in the physiological solution in the perfusion chamber. As such these probes can be used to study the impact of the environment on both cellular and extra-cellular space. Additionally as the chemical properties of the surrounding medium can be controlled and monitored with high precision, these probes enable differential measurement of the target parameter referenced to a stable bath. This approach eliminates the uncertainties associated with non-chemical fluctuations in the fluorescent emission and result in a self-calibrated opto-chemical probe. We have also demonstrated multifunctional probes that are capable of measuring up to three parameters in the extracellular space in brain slices.

  8. Laser Pulse Heating of Spherical Metal Particles

    Directory of Open Access Journals (Sweden)

    Michael I. Tribelsky

    2011-12-01

    Full Text Available We consider the general problem of laser pulse heating of spherical metal particles with the sizes ranging from nanometers to millimeters. We employ the exact Mie solution of the diffraction problem and solve the heat-transfer equation to determine the maximum temperature rise at the particle surface as a function of optical and thermometric parameters of the problem. Primary attention is paid to the case when the thermal diffusivity of the particle is much larger than that of the environment, as it is in the case of metal particles in fluids. We show that, in this case, for any given duration of the laser pulse, the maximum temperature rise as a function of the particle size reaches a maximum at a certain finite size of the particle. We suggest simple approximate analytical expressions for this dependence, which cover the entire parameter range of the problem and agree well with direct numerical simulations.

  9. Sub-micron resolution high-speed spectral domain optical coherence tomography in quality inspection for printed electronics

    Science.gov (United States)

    Czajkowski, J.; Lauri, J.; Sliz, R.; Fält, P.; Fabritius, T.; Myllylä, R.; Cense, B.

    2012-04-01

    We present the use of sub-micron resolution optical coherence tomography (OCT) in quality inspection for printed electronics. The device used in the study is based on a supercontinuum light source, Michelson interferometer and high-speed spectrometer. The spectrometer in the presented spectral-domain optical coherence tomography setup (SD-OCT) is centered at 600 nm and covers a 400 nm wide spectral region ranging from 400 nm to 800 nm. Spectra were acquired at a continuous rate of 140,000 per second. The full width at half maximum of the point spread function obtained from a Parylene C sample was 0:98 m. In addition to Parylene C layers, the applicability of sub-micron SD-OCT in printed electronics was studied using PET and epoxy covered solar cell, a printed RFID antenna and a screen-printed battery electrode. A commercial SD-OCT system was used for reference measurements.

  10. Trends and sources of ozone and sub-micron aerosols at the Mt. Bachelor Observatory during 2004-2015

    Science.gov (United States)

    Zhang, L.; Jaffe, D. A.; Hee, J.

    2016-12-01

    Tropospheric ozone (O3) and airborne particles have significant impacts on human health and the environment. The Mt. Bachelor Observatory (MBO, 2.8 km a.s.l.) in Central Oregon, USA, now has one of the longest continuous free tropospheric records of O3, CO and aerosols in North America. In this study, we report on sources and trends of O3 and sub-micron aerosol scattering at MBO for 2004-2015. For O3, the seasonal cycle shows a bimodal pattern with peaks in April and July, while aerosol scattering (σsp) is lognormally distributed with a very high average in August and a smaller maximum in May. Mean O3 concentrations show a positive and significant trend in all seasons except winter, with an increase of approximately 0.6 ppb/year. This trend appears to be driven by Asian pollution in spring and regional wildfires in summer. For aerosol scattering, we see a significant increase only in summer, driven by recent increases in wildfire activity in the western US. Monthly criteria for isolating free troposphere (FT) and boundary layer (BL) air masses at MBO were obtained based on comparison of MBO water vapor (WV) distributions to those of Salem (SLE) and Medford (MFR), Oregon at equivalent pressure level. In all seasons, FT O3 is, on average, higher than BL O3, but the seasonal patterns are rather similar. For σsp the mean in summer is significantly higher than the FT, indicating the importance of regional wildfire smoke. We have identified four types of air masses that impact O3, CO and aerosols: Asian long range transport (ALRT), regional wildfires, regional industrial pollution, and upper troposphere and lower stratosphere (UTLS) intrusions. Over the 12 years of observations, we have identified 204 individual plume events based on the criteria of 8 consecutive polluted hours with elevated σsp, O3 or CO. Multi-pollutant correlations and backward trajectories were used to differentiate background source categories. A series of enhancement ratios (ERs) including

  11. Prescribed 3-D Direct Writing of Suspended Micron/Sub-micron Scale Fiber Structures via a Robotic Dispensing System.

    Science.gov (United States)

    Yuan, Hanwen; Cambron, Scott D; Keynton, Robert S

    2015-06-12

    A 3-axis dispensing system is utilized to control the initiating and terminating fiber positions and trajectory via the dispensing software. The polymer fiber length and orientation is defined by the spatial positioning of the dispensing system 3-axis stages. The fiber diameter is defined by the prescribed dispense time of the dispensing system valve, the feed rate (the speed at which the stage traverses from an initiating to a terminating position), the gauge diameter of the dispensing tip, the viscosity and surface tension of the polymer solution, and the programmed drawing length. The stage feed rate affects the polymer solution's evaporation rate and capillary breakup of the filaments. The dispensing system consists of a pneumatic valve controller, a droplet-dispensing valve and a dispensing tip. Characterization of the direct write process to determine the optimum combination of factors leads to repeatedly acquiring the desired range of fiber diameters. The advantage of this robotic dispensing system is the ease of obtaining a precise range of micron/sub-micron fibers onto a desired, programmed location via automated process control. Here, the discussed self-assembled micron/sub-micron scale 3D structures have been employed to fabricate suspended structures to create micron/sub-micron fluidic devices and bioengineered scaffolds.

  12. Systematic Sub-Micron Na/Ca Banding in Orbulina universa and bilobata

    Science.gov (United States)

    Bonnin, E. A.; Zhu, Z.; Spero, H. J.; Hoenisch, B.; Russell, A. D.; Fehrenbacher, J. S.; Gagnon, A. C.

    2016-02-01

    Mg/Ca ratios in planktic foraminifera are used widely as a proxy for past sea-surface temperatures. However, over the last decade, it has become clear that these ratios are not constant throughout the shell. Instead these ratios vary systematically by several fold between day and night independent of temperature, a phenomenon that has yet to be explained mechanistically. Determining whether elements other than Mg also exhibit sub-micron banding is essential to properly interpret Me/Ca-based paleoproxies and could help constrain the mechanisms causing Me/Ca variability. Using time-of-flight secondary ion mass spectrometry (ToF-SIMS), an isotope mapping technique with a spatial resolution of roughly 200 nm, we discovered systematic Na/Ca banding in individuals of the symbiont-bearing planktic foraminifer Orbulina universa that had been cultured at constant temperature. Using stable-isotope time stamps, we show that this Na/Ca banding varies inversely with Mg/Ca, with high Na/Ca during the day and low Na/Ca at night for most individuals. Using a combination of analytical models and complementary instrumental techniques, we test whether these patterns can be explained by various ion transport processes. In addition to this Na/Ca banding pattern, there is a distinct region of both high Mg/Ca and high Na/Ca at the location of the primary organic membrane. This POM signature may be a useful way to map organic layers in foraminifera, a method we tested in bilobata, a rare morphotype of O. universa that develops a secondary sphere. Mapping Na/Ca and Mg/Ca in bilobata, we show that an additional organic layer is required during secondary sphere growth and that mineralization occurs over both spheres when this additional quasi-chamber forms. Applying ToF-SIMS and our new understanding of Na/Ca heterogeneity to bilobata is a first step towards connecting the extensive geochemical knowledge developed in O. universa to the multi-chambered species used in paleoceanography.

  13. High Proportions of Sub-micron Particulate Matter in Icelandic Dust Storms in 2015

    Science.gov (United States)

    Dagsson Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur; Magnusdottir, Agnes

    2017-04-01

    Iceland is extremely active dust region and desert areas of over 44,000 km2 acknowledge Iceland as the largest Arctic and European desert. Frequent dust events, up to 135 dust days annually, transport dust particles far distances towards the Arctic and Europe. Satellite MODIS pictures have revealed dust plumes exceeding 1,000 km. The annual dust deposition was calculated as 40.1 million tons yr-1. Two dust storms were measured in transverse horizontal profile about 90 km far from different dust sources in southwestern Iceland in the summer of 2015. Aerosol monitor DustTrak DRX 8533EP was used to measure PM mass concentrations corresponding to PM1, PM2.5, PM4, PM10 and the total PM15 at several places within the dust plume. Images from camera network operated by the Icelandic Road and Coastal Administration were used to estimate the visibility and spatial extent of measured dust events. A numerical simulation of surface winds was carried out with the numerical model HIRLAM with horizontal resolution of 5 km and used to calculate the total dust flux from the sources. The in situ measurements inside the dust plumes showed that aeolian dust can be very fine. The study highlights that suspended volcanic dust in Iceland causes air pollution with extremely high PM1 concentrations comparable to the polluted urban stations in Europe or Asia rather than reported dust event observations from around the world. The PM1/PM2.5 ratios are generally low during dust storms outside of Iceland, much lower than > 0.9 and PM1/PM10 ratios of 0.34-0.63 found in our study. It shows that Icelandic volcanic dust consists of higher proportion of submicron particles compared to crustal dust. The submicron particles are predicted to travel long distances. Moreover, such submicron particles pose considerable health risk because of high potential for entering the lungs. Icelandic volcanic glass has often fine pipe-vesicular structures known from asbestos and high content of heavy metals. Previous

  14. A plasmonic spanner for metal particle manipulation

    NARCIS (Netherlands)

    Zhang, Y.; Shi, W.; Shen, Z.; Man, Z.; Min, C.; Shen, J.; Zhu, S.; Urbach, H.P.; Yuan, X.

    2015-01-01

    Typically, metal particles are difficult to manipulate with conventional optical vortex (OV) tweezers, because of their strong absorption and scattering. However, it has been shown that the vortex field of surface plasmonic polaritons, called plasmonic vortex (PV), is capable of stable trapping and

  15. A Nordic project on high speed low power design in sub-micron CMOS technology for mobile phones

    DEFF Research Database (Denmark)

    Olesen, Ole

    This paper is a survey paper presenting the Nordic CONFRONT project and reporting some results from the group at CIE/DTU, Denmark. The objective of the project is to demonstrate the feasibility of sub-micron CMOS for the realisation of RF front-end circuits operating at frequencies in the 1.......8-2.0 GHz range. The ultimate goal is a single-chip transceiver, requiring only an external band-pass filter between the chip and the antenna. DECT has been chosen as a comparative standard to compare the new approaches developed in the work as well as to facilitate good knowledge transfer to industry. All...

  16. A simple and wide-range refractive index measuring approach by using a sub-micron grating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chun-Wei; Wu, Chun-Che; Lin, Shih-Chieh [Department of Power Mechanical Engineering, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)

    2015-04-13

    This paper presents the design and simulation results of a high-precision low-cost refractometer that demonstrates the main advantage of a wide measurement range (1 ≤ n ≤ 2). The proposed design is based on the diffractive properties of sub-micron gratings and Snell's Law. The precision and uncertainty factors of the proposed system were tested and analyzed, revealing that the proposed refractometer demonstrates a wide measurement range with sensitivity of 10{sup −4}.

  17. Optically and acoustically triggerable sub-micron phase-change contrast agents for enhanced photoacoustic and ultrasound imaging

    Directory of Open Access Journals (Sweden)

    Shengtao Lin

    2017-06-01

    Full Text Available We demonstrate a versatile phase-change sub-micron contrast agent providing three modes of contrast enhancement: 1 photoacoustic imaging contrast, 2 ultrasound contrast with optical activation, and 3 ultrasound contrast with acoustic activation. This agent, which we name ‘Cy-droplet’, has the following novel features. It comprises a highly volatile perfluorocarbon for easy versatile activation, and a near-infrared optically absorbing dye chosen to absorb light at a wavelength with good tissue penetration. It is manufactured via a ‘microbubble condensation’ method. The phase-transition of Cy-droplets can be optically triggered by pulsed-laser illumination, inducing photoacoustic signal and forming stable gas bubbles that are visible with echo-ultrasound in situ. Alternatively, Cy-droplets can be converted to microbubble contrast agents upon acoustic activation with clinical ultrasound. Potentially all modes offer extravascular contrast enhancement because of the sub-micron initial size. Such versatility of acoustic and optical ‘triggerability’ can potentially improve multi-modality imaging, molecularly targeted imaging and controlled drug release.

  18. Optically and acoustically triggerable sub-micron phase-change contrast agents for enhanced photoacoustic and ultrasound imaging.

    Science.gov (United States)

    Lin, Shengtao; Shah, Anant; Hernández-Gil, Javier; Stanziola, Antonio; Harriss, Bethany I; Matsunaga, Terry O; Long, Nicholas; Bamber, Jeffrey; Tang, Meng-Xing

    2017-06-01

    We demonstrate a versatile phase-change sub-micron contrast agent providing three modes of contrast enhancement: 1) photoacoustic imaging contrast, 2) ultrasound contrast with optical activation, and 3) ultrasound contrast with acoustic activation. This agent, which we name 'Cy-droplet', has the following novel features. It comprises a highly volatile perfluorocarbon for easy versatile activation, and a near-infrared optically absorbing dye chosen to absorb light at a wavelength with good tissue penetration. It is manufactured via a 'microbubble condensation' method. The phase-transition of Cy-droplets can be optically triggered by pulsed-laser illumination, inducing photoacoustic signal and forming stable gas bubbles that are visible with echo-ultrasound in situ . Alternatively, Cy-droplets can be converted to microbubble contrast agents upon acoustic activation with clinical ultrasound. Potentially all modes offer extravascular contrast enhancement because of the sub-micron initial size. Such versatility of acoustic and optical 'triggerability' can potentially improve multi-modality imaging, molecularly targeted imaging and controlled drug release.

  19. X-ray imaging with sub-micron resolution using large-area photon counting detectors Timepix

    Science.gov (United States)

    Dudak, J.; Karch, J.; Holcova, K.; Zemlicka, J.

    2017-12-01

    As X-ray micro-CT became a popular tool for scientific purposes a number of commercially available CT systems have emerged on the market. Micro-CT systems have, therefore, become widely accessible and the number of research laboratories using them constantly increases. However, even when CT scans with spatial resolution of several micrometers can be performed routinely, data acquisition with sub-micron precision remains a complicated task. Issues come mostly from prolongation of the scan time inevitably connected with the use of nano-focus X-ray sources. Long exposure time increases the noise level in the CT projections. Furthermore, considering the sub-micron resolution even effects like source-spot drift, rotation stage wobble or thermal expansion become significant and can negatively affect the data. The use of dark-current free photon counting detectors as X-ray cameras for such applications can limit the issue of increased image noise in the data, however the mechanical stability of the whole system still remains a problem and has to be considered. In this work we evaluate the performance of a micro-CT system equipped with nano-focus X-ray tube and a large area photon counting detector Timepix for scans with effective pixel size bellow one micrometer.

  20. A Nordic Project Project on High Speed Low Power Design in Sub-micron CMOS Technology for Mobile

    DEFF Research Database (Denmark)

    Olesen, Ole

    1997-01-01

    This paper is a survey paper presenting the Nordic CONFRONT project and reporting some results from the group at CIE/DTU, Denmark. The objective of the project is to demonstrate the feasibility of sub-micron CMOS for the realisation of RF front-end circuits operating at frequencies in the 1.......8-2.0 GHz range. The ultimate goal is a single-chip transceiver, requiring only an external band-pass filter between the chip and the antenna. DECT has been chosen as a comparative standard to compare the new approaches developed in the work as well as to facilitate good knowledge transfer to industry. All...... of including good off-chip components in the design by use of innovative, inexpensive package technology.To achieve a higher level of integration, the project will use a novel codesign approach to the design strategy. Rather than making specifications based on a purely architectural approach, the work uses...

  1. Simulation of monolithic active pixels in deep sub-micron technologies

    CERN Document Server

    Manolopoulos, S; Turchetta, R

    2002-01-01

    The use of monolithic active pixels (MAPS) has quickly spread in a number of scientific fields ranging from imaging to high-energy particle physics applications. The success of MAPS is due to a number of reasons, for example their low power consumption, fast readout, high spatial resolution and low cost. The latter reflects the use of standard CMOS processes for fabrication. In this paper, the performance of MAPS designed in 0.25 mu m technology will be modelled by means of TCAD device simulation software. The dependence of the device performance on parameters that affect the detection of minimum ionising particles (MIP) will be studied aiming at the optimisation of the detector performance. More specifically, the simulations will focus on the influence of the epitaxial layer thickness on the amount of collected charge, that defines the signal and the cluster size, that affects the spatial resolution.

  2. Filtration of ultrafine metallic particles in industry.

    Science.gov (United States)

    Bémer, D; Morele, Y; Régnier, R

    2015-01-01

    Thermal metal spraying, metal cutting and arc welding processes generate large quantities of ultrafine particles that cause the irreversible clogging of industrial filters. The aim of the study performed was to identify the causes of the clogging of cartridge filters and investigate other paths for cleaning them. This study required the development of a test bench capable of reproducing a thermal spraying process to test the performances of different filtration techniques. This test instrument first, permitted the precise characterization of the aerosol generated by the process and, second, defined the clogging and cleaning conditions for filters. Several parameters were tested: the type of filter, online and off-line cleaning, pre-coating, cleaning by jets of high-speed compressed air via a probe.

  3. Preparation and characterization of sub-micron dispersions of sand in ethylene glycol-water mixture

    OpenAIRE

    Manikandan,S.; Karthikeyan, N.; M Silambarasan; K. S. Suganthi; Rajan, K. S.

    2012-01-01

    Experiments were carried out on the preparation and characterization of dispersions of sand in ethylene glycol-water (50-50%) mixture. The dispersions were prepared by stirred bead milling of 20-30 µm sand (in water) followed by dilution with water and ethylene glycol. The influence of temperature (31-45 ºC), particle concentration (< 2 vol %) and ultrasonication on the viscosity of sand-ethylene glycol-water dispersions was studied. The thermal conductivity of dispersions as a function of pa...

  4. Polyethylene and metal wear particles: characteristics and biological effects.

    Science.gov (United States)

    Catelas, Isabelle; Wimmer, Markus A; Utzschneider, Sandra

    2011-05-01

    This paper first presents a brief overview about the mechanism of wear particle formation as well as wear particle characteristics in metal-on-polyethylene and metal-on-metal artificial hip joints. The biological effects of such particles are then described, focusing on the inflammatory response induced by each type of particles as well as on how metal wear products may be the source of a T lymphocyte-mediated specific immune response, early adverse tissue responses, and genotoxicity. Finally, some of the current in vivo models used for the analysis of tissue response to various wear particles are presented.

  5. Computer simulation of carburizers particles heating in liquid metal

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2010-01-01

    Full Text Available In this article are introduced the problems of computer simulation of carburizers particles heating (anthracite, graphite and petroleum coke, which are present in liquid metal. The diameter of particles, their quantity, relative velocity of particles and liquid metal and the thermophysical properties of materials (thermal conductivity, specific heat and thermal diffusivity have been taken into account in calculations. The analysis has been carried out in the aspect of liquid metal carburization in metallurgical furnaces.

  6. A method for the separation of non-ferrous metal containing particles from a particle stream

    NARCIS (Netherlands)

    Van der Weijden, R.D.; Rem, P.C.

    2004-01-01

    The invention relates to a method for the recovery of non-ferrous metal-comprising particles from a particle stream. According to the invention, the particle stream is put onto a conveyor belt in the form of a monolayer such that with the aid of a liquid, at least the non-ferrous metal comprising

  7. Liquid Metal Phagocytosis: Intermetallic Wetting Induced Particle Internalization.

    Science.gov (United States)

    Tang, Jianbo; Zhao, Xi; Li, Jing; Zhou, Yuan; Liu, Jing

    2017-05-01

    A biomimetic cellular-eating phenomenon in gallium-based liquid metal to realize particle internalization in full-pH-range solutions is reported. The effect, which is called liquid metal phagocytosis, represents a wet-processing strategy to prepare various metallic liquid metal-particle mixtures through introducing excitations such as an electrical polarization, a dissolving medium, or a sacrificial metal. A nonwetting-to-wetting transition resulting from surface transition and the reactive nature of the intermetallic wetting between the two metallic phases are found to be primarily responsible for such particle-eating behavior. Theoretical study brings forward a physical picture to the problem, together with a generalized interpretation. The model developed here, which uses the macroscopic contact angle between the two metallic phases as a criterion to predict the particle internalization behavior, shows good consistency with experimental results.

  8. Corrosion of metal particle and metal evaporated tapes

    Science.gov (United States)

    Speliotis, Dennis E.

    1991-01-01

    Very high coercivity metal particle (MP) and metal evaporated (ME) tapes are being used in 8mm video and digital audio tape applications, and more recently in digital data recording applications. In view of the inherent susceptibility of such media to environmental corrosion, a number of recent studies have addressed their long term stability and archivability. These studies have used an accelerated corrosion test based either on elevated temperature-humidity or polluting gas atmospheres known as Battelle tests. A comparison of the Battelle test results performed at different laboratories reveals a large variation from one location to another, presumably due to incorrect replication of the Battelle condition. Furthermore, when the Battelle tests are performed on enclosed cartridges, it is quite possible that diffusion limits the penetration of the extremely low concentration polluting gaseous species to the inner layers of the tapes during the short time of the accelerated test, whereas in real life these diffusion limitations may not apply. To avoid this uncertainty, the corrosion behavior of commercial 8mm MP and ME tapes when cassettes without their external plastic cases were exposed to 50 deg C and 80 percent RH for 7.5 weeks is investigated.

  9. Material comprising two different non-metallic parrticles having different particle sizes for use in solar reactor

    Science.gov (United States)

    Klausner, James F.; Momen, Ayyoub Mehdizadeh; Al-Raqom, Fotouh A.

    2017-10-03

    Disclosed herein is a composite particle comprising a first non-metallic particle in which is dispersed a second non-metallic particle, where the first non-metallic particle and the second non-metallic particle are inorganic; and where a chemical composition of the first non-metallic particle is different from a chemical composition of the second non-metallic particle; and where the first non-metallic particle and the second non-metallic particle are metal oxides, metal carbides, metal nitrides, metal borides, metal silicides, metal oxycarbides, metal oxynitrides, metal boronitrides, metal carbonitrides, metal borocarbides, or a combination thereof.

  10. On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW – Spain

    Directory of Open Access Journals (Sweden)

    M. Sorribas

    2011-11-01

    Full Text Available This study focuses on the analysis of the sub-micron aerosol characteristics at El Arenosillo Station, a rural and coastal environment in South-western Spain between 1 August 2004 and 31 July 2006 (594 days. The mean total concentration (NT was 8660 cm−3 and the mean concentrations in the nucleation (NNUC, Aitken (NAIT and accumulation (NACC particle size ranges were 2830 cm−3, 4110 cm−3 and 1720 cm−3, respectively. Median size distribution was characterised by a single-modal fit, with a geometric diameter, median number concentration and geometric standard deviation of 60 nm, 5390 cm−3 and 2.31, respectively. Characterisation of primary emissions, secondary particle formation, changes to meteorology and long-term transport has been necessary to understand the seasonal and annual variability of the total and modal particle concentration. Number concentrations exhibited a diurnal pattern with maximum concentrations around noon. This was governed by the concentrations of the nucleation and Aitken modes during the warm seasons and only by the nucleation mode during the cold seasons. Similar monthly mean total concentrations were observed throughout the year due to a clear inverse variation between the monthly mean NNUC and NACC. It was related to the impact of desert dust and continental air masses on the monthly mean particle levels. These air masses were associated with high values of NACC which suppressed the new particle formation (decreasing NNUC. Each day was classified according to a land breeze flow or a synoptic pattern influence. The median size distribution for desert dust and continental aerosol was dominated by the Aitken and accumulation modes, and marine air masses were dominated by the nucleation and Aitken modes. Particles

  11. Particle migration and gap healing around trabecular metal implants

    DEFF Research Database (Denmark)

    Rahbek, O; Kold, S; Zippor, B

    2005-01-01

    Bone on-growth and peri-implant migration of polyethylene particles were studied in an experimental setting using trabecular metal and solid metal implants. Cylindrical implants of trabecular tantalum metal and solid titanium alloy implants with a glass bead blasted surface were inserted either...

  12. Fabrication of a high-aspect-ratio sub-micron tool using a cathode coated with stretched-out insulating layers

    Science.gov (United States)

    Zeng, Yongbin; Wang, Yufeng; Qu, Ningsong; Zhu, Di

    2013-09-01

    This paper describes a method for preparing a high-aspect-ratio sub-micron tool using a cathode coated with stretched-out insulating layers and a straight reciprocating motion applied at the anode via the liquid membrane electrochemical machining (ECM). Simulation results indicate that the application of a cathode coated with stretched-out insulating layers is beneficial for the localization of ECM. Moreover, a mathematical model was derived to estimate the final average diameter of the fabricated tools. Experiments were conducted to verify the versatility and feasibility of the proposed method and its mathematical model. It was observed that the calculated and the experimental results are in good agreement with each other. A sub-micron tool with an average diameter 140.8 nm and an aspect ratio up to 50 was fabricated using the proposed method.

  13. Separating and recycling metals from mixed metallic particles of crushed electronic wastes by vacuum metallurgy.

    Science.gov (United States)

    Zhan, Lu; Xu, Zhenming

    2009-09-15

    During the treatment of electronic wastes, a crushing process is usually used to strip metals from various base plates. Several methods have been applied to separate metals from nonmetals. However, mixed metallic particles obtained from these processes are still a mixture of various metals, including some toxic heavy metals such as lead and cadmium. With emphasis on recovering copper and other precious metals, there have hitherto been no satisfactory methods to recover these toxic metals. In this paper, the criterion of separating metals from mixed metallic particles by vacuum metallurgy is built. The results show that the metals with high vapor pressure have been almost recovered completely, leading to a considerable reduction of environmental pollution. In addition, the purity of copper in mixed particles has been improved from about 80 wt % to over 98 wt %.

  14. SiO2/ZnO Composite Hollow Sub-Micron Fibers: Fabrication from Facile Single Capillary Electrospinning and Their Photoluminescence Properties.

    Science.gov (United States)

    Song, Guanying; Li, Zhenjiang; Li, Kaihua; Zhang, Lina; Meng, Alan

    2017-02-24

    In this work, SiO2/ZnO composite hollow sub-micron fibers were fabricated by a facile single capillary electrospinning technique followed by calcination, using tetraethyl orthosilicate (TEOS), polyvinylpyrrolidone (PVP) and ZnO nanoparticles as raw materials. The characterization results of the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) spectra indicated that the asprepared composite hollow fibers consisted of amorphous SiO2 and hexagonal wurtzite ZnO. The products revealed uniform tubular structure with outer diameters of 400-500 nm and wall thickness of 50-60 nm. The gases generated and the directional escaped mechanism was proposed to illustrate the formation of SiO2/ZnO composite hollow sub-micron fibers. Furthermore, a broad blue emission band was observed in the photoluminescence (PL) of SiO2/ZnO composite hollow sub-micron fibers, exhibiting great potential applications as blue light-emitting candidate materials.

  15. SiO2/ZnO Composite Hollow Sub-Micron Fibers: Fabrication from Facile Single Capillary Electrospinning and Their Photoluminescence Properties

    Directory of Open Access Journals (Sweden)

    Guanying Song

    2017-02-01

    Full Text Available In this work, SiO2/ZnO composite hollow sub-micron fibers were fabricated by a facile single capillary electrospinning technique followed by calcination, using tetraethyl orthosilicate (TEOS, polyvinylpyrrolidone (PVP and ZnO nanoparticles as raw materials. The characterization results of the scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FT-IR spectra indicated that the asprepared composite hollow fibers consisted of amorphous SiO2 and hexagonal wurtzite ZnO. The products revealed uniform tubular structure with outer diameters of 400–500 nm and wall thickness of 50–60 nm. The gases generated and the directional escaped mechanism was proposed to illustrate the formation of SiO2/ZnO composite hollow sub-micron fibers. Furthermore, a broad blue emission band was observed in the photoluminescence (PL of SiO2/ZnO composite hollow sub-micron fibers, exhibiting great potential applications as blue light-emitting candidate materials.

  16. Optimum Disposition of Metal Particles in the Propellant Grain

    Directory of Open Access Journals (Sweden)

    Leonid L. Minkov

    2014-01-01

    Full Text Available Using the dispersed metal in solid propellants to increase the temperature of combustion products leads to such a problem as the specific impulse loss due to the incomplete combustion of metal particles in the exhaust products. A redistribution of metal loaded into the propellant grain is one of the methods to decrease the specific impulse loss. This paper reports on the ways to obtain the optimum metal particle disposition for the case-bounded propellant grain of tube cross-sectional type. Three different approaches to analyze the metal combustion efficiency are discussed. The influence of the dynamic nonequilibrium of two-phase flow on the optimum metal particles disposition in the propellant grain of tube cross-sectional type is investigated.

  17. Trends and sources of ozone and sub-micron aerosols at the Mt. Bachelor Observatory (MBO) during 2004-2015

    Science.gov (United States)

    Zhang, Lei; Jaffe, Daniel A.

    2017-09-01

    In this paper, we report the climatology of tropospheric ozone (O3) and sub-micron aerosol scattering at the Mt. Bachelor Observatory (MBO, 2.8 km asl) in central Oregon, USA, during 2004-2015. The seasonal cycle for O3 showed a bimodal pattern with peaks in April and July, while aerosol scattering (σsp) was lognormally distributed with a very high peak in August and a smaller peak in May. The mean O3 concentrations showed positive and significant trends in all seasons except winter, with a slope of 0.6-0.8 ppbv yr-1. Monthly criteria for isolating free tropospheric (FT) and boundary layer influenced (BLI) air masses at MBO were obtained based on comparison of MBO water vapor (WV) distributions to those of Salem (SLE) and Medford (MFR), Oregon, at equivalent pressure level. In all seasons, FT O3 was, on average, higher than BLI O3, but the seasonal patterns were rather similar. For σsp the FT mean in spring was higher, but the BLI mean in summer was significantly higher, indicating the importance of regional wildfire smoke. To better understand the causes for the seasonal and interannual trends at MBO, we identified four major categories of air masses that impact O3, carbon monoxide (CO) and aerosols: upper troposphere and lower stratosphere (UTLS) O3 intrusion, Asian long-range transport (ALRT), Arctic air pollution (AAP) and plumes from the Pacific Northwest region (PNW). ALRT and PNW plumes can be further divided into wildfires (WF), industrial pollution (IP) and mineral dust (MD). Over the 12 years of observations, 177 individual plume events have been identified. Enhancement ratios (ERs) and Ångström exponents (AEs) of aerosols were calculated for all events. The lowest slope of Δσsp/ΔO3 is a unique feature of UTLS events. PNW-WF events have the highest averages for Δσsp/ΔCO, Δσsp/ΔO3 and Δσsp/ΔNOy compared to other events. These ERs decrease during long-range transport due to the shorter residence time of aerosols compared to the other

  18. Porous metal oxide particles and their methods of synthesis

    Science.gov (United States)

    Chen, Fanglin; Liu, Qiang

    2013-03-12

    Methods are generally disclosed for synthesis of porous particles from a solution formed from a leaving agent, a surfactant, and a soluble metal salt in a solvent. The surfactant congregates to form a nanoparticle core such that the metal salt forms about the nanoparticle core to form a plurality of nanoparticles. The solution is heated such that the leaving agent forms gas bubbles in the solution, and the plurality of nanoparticles congregate about the gas bubbles to form a porous particle. The porous particles are also generally disclosed and can include a particle shell formed about a core to define an average diameter from about 0.5 .mu.m to about 50 .mu.m. The particle shell can be formed from a plurality of nanoparticles having an average diameter of from about 1 nm to about 50 nm and defined by a metal salt formed about a surfactant core.

  19. Plasma polymer-functionalized silica particles for heavy metals removal.

    Science.gov (United States)

    Akhavan, Behnam; Jarvis, Karyn; Majewski, Peter

    2015-02-25

    Highly negatively charged particles were fabricated via an innovative plasma-assisted approach for the removal of heavy metal ions. Thiophene plasma polymerization was used to deposit sulfur-rich films onto silica particles followed by the introduction of oxidized sulfur functionalities, such as sulfonate and sulfonic acid, via water-plasma treatments. Surface chemistry analyses were conducted by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Electrokinetic measurements quantified the zeta potentials and isoelectric points (IEPs) of modified particles and indicated significant decreases of zeta potentials and IEPs upon plasma modification of particles. Plasma polymerized thiophene-coated particles treated with water plasma for 10 min exhibited an IEP of less than 3.5. The effectiveness of developed surfaces in the adsorption of heavy metal ions was demonstrated through copper (Cu) and zinc (Zn) removal experiments. The removal of metal ions was examined through changing initial pH of solution, removal time, and mass of particles. Increasing the water plasma treatment time to 20 min significantly increased the metal removal efficiency (MRE) of modified particles, whereas further increasing the plasma treatment time reduced the MRE due to the influence of an ablation mechanism. The developed particulate surfaces were capable of removing more than 96.7% of both Cu and Zn ions in 1 h. The combination of plasma polymerization and oxidative plasma treatment is an effective method for the fabrication of new adsorbents for the removal of heavy metals.

  20. Models for Metal Hydride Particle Shape, Packing, and Heat Transfer

    OpenAIRE

    Smith, Kyle C.; Fisher, Timothy S.

    2012-01-01

    A multiphysics modeling approach for heat conduction in metal hydride powders is presented, including particle shape distribution, size distribution, granular packing structure, and effective thermal conductivity. A statistical geometric model is presented that replicates features of particle size and shape distributions observed experimentally that result from cyclic hydride decrepitation. The quasi-static dense packing of a sample set of these particles is simulated via energy-based structu...

  1. Metal Diffusion in Smoothed Particle Hydrodynamics Simulations of Dwarf Galaxies

    Science.gov (United States)

    Williamson, David; Martel, Hugo; Kawata, Daisuke

    2016-05-01

    We perform a series of smoothed particle hydrodynamics simulations of isolated dwarf galaxies to compare different metal mixing models. In particular, we examine the role of diffusion in the production of enriched outflows and in determining the metallicity distributions of gas and stars. We investigate different diffusion strengths by changing the pre-factor of the diffusion coefficient, by varying how the diffusion coefficient is calculated from the local velocity distribution, and by varying whether the speed of sound is included as a velocity term. Stronger diffusion produces a tighter [O/Fe]-[Fe/H] distribution in the gas and cuts off the gas metallicity distribution function at lower metallicities. Diffusion suppresses the formation of low-metallicity stars, even with weak diffusion, and also strips metals from enriched outflows. This produces a remarkably tight correlation between “metal mass-loading” (mean metal outflow rate divided by mean metal production rate) and the strength of diffusion, even when the diffusion coefficient is calculated in different ways. The effectiveness of outflows at removing metals from dwarf galaxies and the metal distribution of the gas is thus dependent on the strength of diffusion. By contrast, we show that the metallicities of stars are not strongly dependent on the strength of diffusion, provided that some diffusion is present.

  2. Nanostructured metal particle-modified electrodes for ...

    Indian Academy of Sciences (India)

    face-dominated properties, which significantly differ from those of the bulk material. The integration of metal nanoparticles into thin film of permselective membrane is particularly important for various appli- cations, for example in biological ... tally interesting class of materials, in part because of an apparent dichotomy which ...

  3. Numerical modelling of electrochemical polarization around charged metallic particles

    Science.gov (United States)

    Bücker, Matthias; Undorf, Sabine; Flores Orozco, Adrián; Kemna, Andreas

    2017-04-01

    We extend an existing analytical model and carry out numerical simulations to study the polarization process around charged metallic particles immersed in an electrolyte solution. Electro-migration and diffusion processes in the electrolyte are described by the Poisson-Nernst-Planck system of partial differential equations. To model the surface charge density, we consider a time- and frequency-invariant electric potential at the particle surface, which leads to the build-up of a static electrical double layer (EDL). Upon excitation by an external electric field at low frequencies, we observe the superposition of two polarization processes. On the one hand, the induced dipole moment on the metallic particle leads to the accumulation of opposite charges in the electrolyte. This charge polarization corresponds to the long-known response of uncharged metallic particles. On the other hand, the unequal cation and anion concentrations in the EDL give rise to a salinity gradient between the two opposite sides of the metallic particle. The resulting concentration polarization enhances the magnitude of the overall polarization response. Furthermore, we use our numerical model to study the effect of relevant model parameters such as surface charge density and ionic strength of the electrolyte on the resulting spectra of the effective conductivity of the composite model system. Our results do not only give interesting new insight into the time-harmonic variation of electric potential and ion concentrations around charged metallic particle. They are also able to reduce incongruities between earlier model predictions and geophysical field and laboratory measurements. Our model thereby improves the general understanding of IP signatures of metallic particles and represents the next step towards a quantitative interpretation of IP imaging results. Part of this research is funded by the Austrian Federal Ministry of Science, Research and Economy under the Raw Materials Initiative.

  4. Controlled Shrinkage of Expanded Glass Particles in Metal Syntactic Foams.

    Science.gov (United States)

    Al-Sahlani, Kadhim; Taherishargh, Mehdi; Kisi, Erich; Fiedler, Thomas

    2017-09-13

    Metal matrix syntactic foams have been fabricated via counter-gravity infiltration of a packed bed of recycled expanded glass particles (EG) with A356 aluminum alloy. Particle shrinkage was studied and has been utilized to increase the particles' strength and tailor the mechanical properties of the expanded glass/metal syntactic foam (EG-MSF). The crushing strength of particles could be doubled by shrinking them for 20 min at 700 °C. Owing to the low density of EG (0.20-0.26 g/cm³), the resulting foam exhibits a low density (1.03-1.19 g/cm³) that increases slightly due to particle shrinkage. Chemical and physical analyses of EG particles and the resulting foams were conducted. Furthermore, metal syntactic foam samples were tested in uni-axial compression tests. The stress-strain curves obtained exhibit three distinct regions: elastic deformation followed by a stress plateau and densification commencing at 70-80% macroscopic strain. Particle shrinkage increased the mechanical strength of the foam samples and their average plateau stress increased from 15.5 MPa to 26.7 MPa.

  5. Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure

    Directory of Open Access Journals (Sweden)

    Junlong Tian

    2015-06-01

    Full Text Available In this work, Au-Bi2Te3 nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus forewing (T_FW as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi2Te3 nanocomposite thermoelectric film was analyzed by X-ray diffraction (XRD, field-emission scanning-electron microscopy (FESEM, and transmission electron microscopy (TEM. Coupled the plasmon resonances of the Au nanoparticles with the hierarchical sub-micron antireflection quasi-periodic structure, the Au-Bi2Te3 nanocomposite thermoelectric film possesses an effective infrared absorption and infrared photothermal conversion performance. Based on the finite difference time domain method and the Joule effect, the heat generation and the heat source density distribution of the Au-Bi2Te3 nanocomposite thermoelectric film were studied. The heterogeneity of heat source density distribution of the Au-Bi2Te3 nanocomposite thermoelectric film opens up a novel promising technique for generating thermoelectric power under illumination.

  6. Sub-micron resolution surface plasmon resonance imaging enabled by nanohole arrays with surrounding Bragg mirrors for enhanced sensitivity and isolation.

    Science.gov (United States)

    Lindquist, Nathan C; Lesuffleur, Antoine; Im, Hyungsoon; Oh, Sang-Hyun

    2009-02-07

    We present nanohole arrays in thin gold films as sub-micron resolution surface plasmon resonance (SPR) imaging pixels in a microarray format. With SPR imaging, the resolution is not limited by diffraction, but by the propagation of surface plasmon waves to adjacent sensing areas, or nanohole arrays, causing unwanted interference. For ultimate scalability, several issues need to be addressed, including: (1) as several nanohole arrays are brought close to each other, surface plasmon interference introduces large sources of error; and (2) as the size of the nanohole array is reduced, i.e. fewer holes, detection sensitivity suffers. To address these scalability issues, we surround each biosensing pixel (a 3-by-3 nanohole array) with plasmonic Bragg mirrors, blocking interference between adjacent SPR sensing pixels for high-density packing, while maintaining the sensitivity of a 50 x larger footprint pixel (a 16-by-16 nanohole array). We measure real-time, label-free streptavidin-biotin binding kinetics with a microarray of 600 sub-micron biosensing pixels at a packing density of more than 10(7) per cm(2).

  7. The synthesis of metal nanoparticulate catalysts within functional microgel particles

    Science.gov (United States)

    Kaliva, Maria; Pavlopoulou, Eleni; Christodoulakis, Konstantinos; Vamvakaki, Maria; Anastasiadis, Spiros H.

    2012-02-01

    Electrostatically and sterically stabilized polymer microgel particles have been prepared containing either amino (poly(2-(diethylamino)ethyl methacrylate), PDEA) or carboxylic acid (poly(acrylic acid), PAA; poly(methacrylic acid), PMMA) functional groups. The PDEA, PAA and PMAA particles can be used for the incorporation of a large variety of metal nanoparticulate catalysts due to their functional amine and carboxylic acid groups; Pd, Ru and Ni nanoparticles have been synthesized. The more polar PAA microgels were designed as the nanocatalyst carrier system in aqueous reaction media while the less polar PMAA particles were prepared as the metal nanoparticle template for use in catalytic reactions that take place in organic solvents. The sterically and electrostatically stabilized microgel particles possess surface functional groups that can potentially interact with the microchannel walls of microfluidic catalytic reactors.

  8. Metal diffusion in smoothed particle hydrodynamics simulations of dwarf galaxies

    OpenAIRE

    Williamson, David John; Martel, Hugo; Kawata, Daisuke

    2016-01-01

    We perform a series of smoothed particle hydrodynamics simulations of isolated dwarf galaxies to compare different metal mixing models. In particular, we examine the role of diffusion in the production of enriched outflows, and in determining the metallicity distributions of gas and stars. We investigate different diffusion strengths, by changing the pre-factor of the diffusion coefficient, by varying how the diffusion coefficient is calculated from the local velocity distribution, and by var...

  9. The Particle Distribution in Liquid Metal with Ceramic Particles Mould Filling Process

    Science.gov (United States)

    Dong, Qi; Xing, Shu-ming

    2017-09-01

    Adding ceramic particles in the plate hammer is an effective method to increase the wear resistance of the hammer. The liquid phase method is based on the “with the flow of mixed liquid forging composite preparation of ZTA ceramic particle reinforced high chromium cast iron hammer. Preparation method for this system is using CFD simulation analysis the particles distribution of flow mixing and filling process. Taking the 30% volume fraction of ZTA ceramic composite of high chromium cast iron hammer as example, by changing the speed of liquid metal viscosity to control and make reasonable predictions of particles distribution before solidification.

  10. Nanostructured films of metal particles obtained by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Muniz-Miranda, M., E-mail: muniz@unifi.it [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Gellini, C. [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Giorgetti, E.; Margheri, G.; Marsili, P. [Istituto Sistemi Complessi (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Lascialfari, L.; Becucci, L. [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Trigari, S. [Istituto Sistemi Complessi (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Giammanco, F. [Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy)

    2013-09-30

    Colloidal dispersions of silver and gold nanoparticles were obtained in pure water by ablation with nanosecond pulsed laser. Then, by filtration of the metal particles on alumina, we fabricated nanostructured films, whose surface morphology was examined by atomic force microscopy (AFM) and related to surface-enhanced Raman scattering (SERS) after adsorption of adenine. - Highlights: • Ag and Au colloidal nanoparticles were obtained by laser ablation. • Nanostructured Ag and Au films were fabricated by filtration of metal nanoparticles. • Surface morphology of metal films was investigated by atomic force microscopy. • Surface-enhanced Raman spectra (SERS) of adenine on metal films were obtained. • SERS enhancements were related to the surface roughness of the metal films.

  11. Particle size and metal distributions in anaerobically digested pig slurry.

    Science.gov (United States)

    Marcato, Claire E; Pinelli, Eric; Pouech, Philippe; Winterton, Peter; Guiresse, Maritxu

    2008-05-01

    Particle size distribution and trace element patterns were studied in a full-scale anaerobic digestion plant treating pig slurry. Mass balance was established for major (N, P, K, Ca, Fe, Mg and S) and minor (Al, Cu, Mn and Zn) elements. Most of the elements were conserved through the process but part of the P, Ca, Mg and Mn was deposited as crystals lining the digester. In the dry matter of the slurry, Cu and Zn occurred at between 170 and 2600 mg kg(-1) due to pig diet supplements. Analyses of particle size distributions in raw and digested slurries showed a general shift in distribution towards larger sizes due to degradation of small and easily degradable particles as well as formation of large microbial filaments. Graded sieving of digested slurry showed metals to be mainly present on 3-25 microm particles. Less than 2% Cu and Zn was removed by passage through a 250 microm rotary screen.

  12. Properties of particle phases for metal-matrix-composite design.

    Science.gov (United States)

    Baron, C; Springer, H

    2017-06-01

    Successful metallurgical design of metal-matrix-composites relies on the knowledge of the intrinsic property profiles of the metal matrix and especially the compounds employed for particles, whiskers or fibres. In this work we compiled the key properties melting point, bulk modulus, shear modulus, Young׳s modulus, density, hardness, Poisson׳s ratio and structure/space group from the widespread literature data for the most relevant compound types, i.e. borides, carbo-borides, carbides, oxides, nitrides and intermetallic phases.

  13. Refractory metal particles in refractory inclusions in the Allende meteorite

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, L. H.; Blander, M.

    1980-01-01

    An examination of refractory metal particles in five calcium-aluminum-rich inclusions in the Allende meteorite indicates a complex variety of compositions and large departures from equilibrium. These particles appear to have been primordial condensates which were isolated from the nebula and from each other at different times by cocondensing oxides. Selective diffusion and/or oxidation of the more oxidizable metals (Mo, W, Fe and Ni), phase segregations into different alloy phases (fcc, bcc, hcp and perhaps ordered phases) and the formation of metastable condensates appears to have been involved in the modification of these materials to their present state. Only a small fraction of our observations cannot be reconciled with this picture because of a lack of knowledge of some of the phase equilibria which might have bee involved.

  14. High performance imaging of relativistic soft X-ray harmonics by sub-micron resolution LiF film detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pikuz, Tatiana; Faenov, Anatoly [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Pirozhkov, Alexander; Esirkepov, Timur; Koga, James; Nakamura, Tatsufumi; Bulanov, Sergei; Fukuda, Yuji; Hayashi, Yukio; Kotaki, Hideyuki; Kando, Masaki [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Astapov, Artem; Pikuz, Sergey Jr. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Klushin, Georgy [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); International Laser Center of M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Nagorskiy, Nikolai; Magnitskiy, Sergei [International Laser Center of M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Kato, Yoshiaki [The Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka (Japan)

    2012-12-15

    The spectrum variation and the coherent properties of the high-order harmonics (HOH) generated by an oscillating electron spikes formed at the joint of the boundaries of a cavity and a bow wave, which are created by a relativistically self-focusing laser in underdense gas jet plasma, are investigated. This new mechanism for HOH generation efficiently produces emission from ultraviolet up to the XUV ''water window'' spectral range. To characterize such source in the wide spectral range a diffraction imaging technique is applied. High spatial resolution EUV and soft X-ray LiF film detector have been used for precise measurements of diffraction patterns. The measurements under observation angle of 8 to the axis of laser beam propagation have been performed. The diffraction patterns were observed on the detector clearly, when the square mesh was placed at the distance of 500 mm from the output of plasma and at the distance of 27.2 mm in front of the detector. It is shown that observed experimental patterns are well consistent with modeled ones for theoretical HOH spectrum, provided by particle-in-cell simulations of a relativistic-irradiance laser pulse interaction with underdense plasma (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Enhanced sun protection of nano-sized metal oxide particles over conventional metal oxide particles: an in vitro comparative study.

    Science.gov (United States)

    Singh, P; Nanda, A

    2014-06-01

    A systematic and detailed study has been designed and conducted, taking into account some of the proposed benefits such as increased efficiency, transparency, unique texture, protection of active ingredient and higher consumer compliance of cosmetics containing nano-sized metal oxides. This study also presents an in vitro method to determine sun protection factor of the investigational sunscreen cream samples containing zinc oxide and titanium dioxide with a varied range of particle size. Finally, a comparative study has been conducted between metal oxide particles, conventional as well as nanoparticles. All the skin cosmetics formulated were thermally stable with a pH ranging from 7.9 to 8.2. Moreover, the fatty acid substance content and residue were found to be analogous to the standard values in each skin cosmetic. The skin cosmetics containing the titanium or zinc oxide nanoparticles were found to have improved spreadability as compared to skin cosmetics containing conventional titanium or zinc oxide particles, respectively. All skin cosmetics were found to have uniform distribution of the particles. The sunscreen creams containing zinc oxide nanoparticles and titanium dioxide nanoparticles were found to have higher in vitro sun protection factor (SPF of 3.65 for ZnO nanoparticles and 4.93 for TiO2 nanoparticles) as compared to that of sunscreen creams containing conventional zinc oxide particles (SPF = 2.90) and conventional titanium dioxide (SPF = 1.29), clearly indicating the effect of reduction in particles size, from micro to nano, on the sun protection factor. Good texture, better spreadability and enhanced in vitro SPF proved the advantageous role of nanoparticles in cosmetics. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  16. Imaging of vaporised sub-micron phase change contrast agents with high frame rate ultrasound and optics.

    Science.gov (United States)

    Lin, Shengtao; Zhang, Ge; Jamburidze, Akaki; Chee, Melisse; Leow, Chee Hau; Garbin, Valeria; Tang, Meng-Xing

    2018-01-31

    Phase-change ultrasound contrast agent (PCCA), or nanodroplet shows promises as an alternative to conventional microbubble agent over a wide range of diagnostic applications. In the meantime, high-frame-rate (HFR) ultrasound imaging with microbubbles enables unprecedentedly temporal resolution compared to traditional contrast-enhanced ultrasound imaging. The combination of HFR ultrasound imaging and PCCAs can offer opportunities to observe and better understand PCCA behaviour after vaporisation capturing the fast phenomenon at a high temporal resolution. In this study, we utilised HFR ultrasound at frame rates in the kilohertz range (5-20 kHz) to image the native and size-selected PCCA populations immediately after vaporisation in vitro with clinical acoustic parameters. The size-selected PCCAs through filtration are shown to preserve submicron-sized (mean diameter < 200 nm) population without micron-sized outliers (> 1 µm) that are originally from the native PCCA emulsion. The results demonstrate imaging signals with different amplitude and temporal features compared to that of microbubbles. Compared with microbubbles, both B-mode and Pulse-Inversion (PI) signals from vaporised PCCA populations were reduced significantly in the first tens of milliseconds, while only B-mode signals from the PCCAs recovered during the next 400 ms, suggesting significant changes to the size distribution of PCCAs after vaporisation. It is also shown that such recovery in signal over time is not evident when using size-selective PCCAs. Furthermore, it was found that signals from the vaporised PCCA populations are affected by the amplitude and frame rate of the HFR ultrasound imaging. Using high-speed optical camera observation (30 kHz), we observed the particle size change in the vaporised PCCA populations exposed to the HFR ultrasound imaging pulses. These findings can benefit the understandings of PCCA behaviour under HFR ultrasound imaging. © 2018 Institute of Physics and

  17. Oil metal particles Detection Algorithm Based on Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Shang Wei

    2017-01-01

    Full Text Available In order to observe the real-time abrasion status of the aero-engine, we need to monitor the lubrication system online. As the aero-engine operating time and running state changes, the concentration, composition, size and other parameters of the metal debris can show different changes. They can be used as an important indicator to reflect the state of the aero-engine fault. However, due to the influence of electromagnetic, vibration disturbance and random noise signal introduced by the processing unit itself, the metal particles signal tend to comprise noise. Oil metal particles detection algorithm based on wavelet transform, utilizes the optimized localized nature in time domain and frequency domain of wavelet transform and the characteristics of multi-resolution analysis, combined with the signal characteristics in actual aero-engine condition to realize noise reduction and detection, while validating the algorithm using real experimental data. The result shows that noise can be effectively decreased and signal characteristics can be detected correctly.

  18. The fate of meteoric metals in ice particles: Effects of sublimation and energetic particle bombardment

    Science.gov (United States)

    Mangan, T. P.; Frankland, V. L.; Murray, B. J.; Plane, J. M. C.

    2017-08-01

    The uptake and potential reactivity of metal atoms on water ice can be an important process in planetary atmospheres and on icy bodies in the interplanetary and interstellar medium. For instance, metal atom uptake affects the gas-phase chemistry of the Earth's mesosphere, and has been proposed to influence the agglomeration of matter into planets in protoplanetary disks. In this study the fate of Mg and K atoms incorporated into water-ice films, prepared under ultra-high vacuum conditions at temperatures of 110-140 K, was investigated. Temperature-programmed desorption experiments reveal that Mg- and K-containing species do not co-desorb when the ice sublimates, demonstrating that uptake on ice particles causes irreversible removal of the metals from the gas phase. This implies that uptake on ice particles in terrestrial polar mesospheric clouds accelerates the formation of large meteoric smoke particles (≥1 nm radius above 80 km) following sublimation of the ice. Energetic sputtering of metal-dosed ice layers by 500 eV Ar+ and Kr+ ions shows that whereas K reacts on (or within) the ice surface to form KOH, adsorbed Mg atoms are chemically inert. These experimental results are consistent with electronic structure calculations of the metals bound to an ice surface, where theoretical adsorption energies on ice are calculated to be -68 kJ mol-1 for K, -91 kJ mol-1 for Mg, and -306 kJ mol-1 for Fe. K can also insert into a surface H2O to produce KOH and a dangling H atom, in a reaction that is slightly exothermic.

  19. Physical sputtering of metallic systems by charged-particle impact

    Energy Technology Data Exchange (ETDEWEB)

    Lam, N.Q.

    1989-12-01

    The present paper provides a brief overview of our current understanding of physical sputtering by charged-particle impact, with the emphasis on sputtering of metals and alloys under bombardment with particles that produce knock-on collisions. Fundamental aspects of ion-solid interactions, and recent developments in the study of sputtering of elemental targets and preferential sputtering in multicomponent materials are reviewed. We concentrate only on a few specific topics of sputter emission, including the various properties of the sputtered flux and depth of origin, and on connections between sputtering and other radiation-induced and -enhanced phenomena that modify the near-surface composition of the target. The synergistic effects of these diverse processes in changing the composition of the integrated sputtered-atom flux is described in simple physical terms, using selected examples of recent important progress. 325 refs., 27 figs.

  20. Image-Guided Ultrasound Characterization of Volatile Sub-Micron Phase-Shift Droplets in the 20-40 MHz Frequency Range.

    Science.gov (United States)

    Sheeran, Paul S; Daghighi, Yasaman; Yoo, Kimoon; Williams, Ross; Cherin, Emmanuel; Foster, F Stuart; Burns, Peter N

    2016-03-01

    Phase-shift perfluorocarbon droplets are designed to convert from the liquid to the gas state by the external application of acoustic or optical energy. Although droplet vaporization has been investigated extensively at ultrasonic frequencies between 1 and 10 MHz, few studies have characterized performance at the higher frequencies commonly used in small animal imaging. In this study, we use standard B-mode imaging sequences on a pre-clinical ultrasound platform to both image and activate sub-micron decafluorobutane droplet populations in vitro and in vivo at center frequencies in the range of 20-40 MHz. Results show that droplets remain stable against vaporization at low imaging pressures but are vaporized at peak negative pressures near 3.5 MPa at the three frequencies tested. This study also found that a small number of size outliers present in the distribution can greatly influence droplet performance. Removal of these outliers results in a more accurate assessment of the vaporization threshold and produces free-flowing microbubbles upon vaporization in the mouse kidney. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  1. A Fast, Versatile Nanoprobe for Complex Materials: The Sub-micron Resolution X-ray Spectroscopy Beamline at NSLS-II (491st Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, Juergen [BNL Photon Sciences Directorate

    2014-02-06

    Time is money and for scientists who need to collect data at research facilities like Brookhaven Lab’s National Synchrotron Light Source (NSLS), “beamtime” can be a precious commodity. While scanning a complex material with a specific technique and standard equipment today would take days to complete, researchers preparing to use brighter x-rays and the new sub-micron-resolution x-ray spectroscopy (SRX) beamline at the National Synchrotron Light Source II (NSLS-II) could scan the same sample in greater detail with just a few hours of beamtime. Talk about savings and new opportunities for researchers! Users will rely on these tools for locating trace elements in contaminated soils, developing processes for nanoparticles to deliver medical treatments, and much more. Dr. Thieme explains benefits for next-generation research with spectroscopy and more intense x-rays at NSLS-II. He discusses the instrumentation, features, and uses for the new SRX beamline, highlighting its speed, adjustability, and versatility for probing samples ranging in size from millimeters down to the nanoscale. He will talk about complementary beamlines being developed for additional capabilities at NSLS-II as well.

  2. Synthesis and self-assembly of dumbbell shaped ZnO sub-micron structures using low temperature chemical bath deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Borade, P. [National Centre for Nanoscience and Nanotechnology, University of Mumbai, Kalina Campus, Santacruz (E), Mumbai 400098 (India); Joshi, K.U. [Anton-Paar India Pvt. Ltd., Thane (W), 400607 (India); Gokarna, A.; Lerondel, G. [Laboratoire de Nanotechnologie et D' Instrumentation Optique, Institut Charles Delaunay, CNRS UMR 6281, Université de Technologie de Troyes, 12 Rue Marie Curie, BP 2060, 10010 Troyes (France); Walke, P. [National Centre for Nanoscience and Nanotechnology, University of Mumbai, Kalina Campus, Santacruz (E), Mumbai 400098 (India); Late, D. [National Chemical Laboratory (NCL), Pune 400027 (India); Jejurikar, S.M., E-mail: jejusuhas@gmail.com [National Centre for Nanoscience and Nanotechnology, University of Mumbai, Kalina Campus, Santacruz (E), Mumbai 400098 (India)

    2016-02-01

    We report well dispersed horizontal growth of ZnO sub-micron structures using simplest technique ever known i.e. chemical bath deposition (CBD). A set of samples were prepared under two different cases A) dumbbell shaped ZnO grown in CBD bath and B) tubular ZnO structures evolved from dumbbell shaped structures by dissolution mechanism. Single phase wurtzite ZnO formation is confirmed using X-ray diffraction (XRD) technique in both cases. From the morphological investigations performed using scanning electron microscopy (SEM), sample prepared under case A indicate formation of hex bit tool (HBT) shaped ZnO crystals, which observed to self-organize to form dumbbell structures. Further these microstructures are then converted into tubular structures as a fragment of post CBD process. The possible mechanism responsible for the self-assembly of HBT units to form dumbbell structures is discussed. Observed free excitonic peak located at 370 nm in photoluminescence (PL) spectra recorded at 18 K indicate that the micro/nanostructures synthesized using CBD are of high optical quality. - Highlights: • Controlled growth of Dumbbell shaped ZnO using Chemical Bath Deposition (CBD). • Growth mechanism of dumbbell shaped ZnO by self-assembling was discussed. • Quick Transformation of ZnO dumbbell structures in to tubular structures by dissolution. • Sharp UV Emission at 370 nm from both dumbbell and tubular structures.

  3. Scaling down the two-dimensional electron gas spin resonance (ESR) phenomena in GaAs/AlGaAs heterostructures to sub-micron samples

    Science.gov (United States)

    Bandaru, Prabhakar; Yablonovitch, Eli; Jiang, Hong-Wen

    2002-03-01

    Electron Spin Resonance (ESR) has been proposed as a technique for achieving single electron and subsequently single spin control, important for the emerging fields of spintronics and quantum computing. In this paper, we report on ESR in the quantum Hall regime, of sub-micron structures containing a few hundred electrons. These phenomena are contrasted with ESR phenomena in structures containing 10^7 - 10^9 electrons, which have been performed so far (Reference 1). There are several novel features observed in the ESR of small structures, such as a very large decrease of resistance and shift in the quantum Hall minima to lower magnetic fields after the resonance. These imply a reduction in the number of electrons and could result from the greater influence of the surface and impurity potential fluctuations intrinsic to a small sample. The ESR peak intensity is hypothesized to result from the transfer of electrons from the localized states to the extended states. References: 1.H.W.Jiang and E. Yablonovitch, Phys. Rev.B., 64, R041307, (2001) 2.M.Dobers, K.v. Klitzing and G. Weimann,Phys. Rev. B, 38, 5453, (1988).

  4. Sub-micron and nanoscale feature depth modulates alignment of stromal fibroblasts and corneal epithelial cells in serum-rich and serum-free media.

    Science.gov (United States)

    Fraser, Sarah A; Ting, Yuk-Hong; Mallon, Kelly S; Wendt, Amy E; Murphy, Christopher J; Nealey, Paul F

    2008-09-01

    Topographic features are generally accepted as being capable of modulating cell alignment. Of particular interest is the potential that topographic feature geometry induces cell alignment indirectly through impacting adsorbed proteins from the cell culture medium on the surface of the substrate. However, it has also been reported that micron-scale feature depth significantly impacts the level of alignment of cellular populations on topography, despite being orders of magnitude larger than the average adsorbed protein layer (nm). In order to better determine the impact of biomimetic length scale topography and adsorbed protein interaction on cellular morphology we have systematically investigated the effect of combinations of sub-micron to nanoscale feature depth and lateral pitch on corneal epithelial cell alignment. In addition we have used the unique properties of a serum-free media alternative in direct comparison to serum-rich medium to investigate the role of culture medium protein composition on cellular alignment to topographically patterned surfaces. Our observation that increasing groove depth elicited larger populations of corneal epithelial cells to align regardless of culture medium composition and of cell orientation with respect to the topography, suggests that these cells can sense changes in topographic feature depths independent of adsorbed proteins localized along ridge edges and tops. However, our data also suggests a strong combinatory effect of topography with culture medium composition, and also a cell type dependency in determining the level of cell elongation and alignment to nanoscale topographic features.

  5. Sub-micron and nanoscale feature depth modulates alignment of stromal fibroblasts and corneal epithelial cells in serum-rich and serum-free media

    Science.gov (United States)

    Fraser, Sarah A.; Ting, Yuk-Hong; Mallon, Kelly S.; Wendt, Amy E.; Murphy, Christopher J.; Nealey, Paul F.

    2011-01-01

    Topographic features are generally accepted as being capable of modulating cell alignment. Of particular interest is the potential that topographic feature geometry induces cell alignment indirectly through impacting adsorbed proteins from the cell culture medium on the surface of the substrate. However, it has also been reported that micron-scale feature depth significantly impacts the level of alignment of cellular populations on topography, despite being orders of magnitude larger than the average adsorbed protein layer (nm). In order to better determine the impact of biomimetic length scale topography and adsorbed protein interaction on cellular morphology we have systematically investigated the effect of combinations of sub-micron to nanoscale feature depth and lateral pitch on corneal epithelial cell alignment. In addition we have used the unique properties of a serum-free media alternative in direct comparison to serum-rich medium to investigate the role of culture medium protein composition on cellular alignment to topographically patterned surfaces. Our observation that increasing groove depth elicited larger populations of corneal epithelial cells to align regardless of culture medium composition and of cell orientation with respect to the topography, suggests that these cells can sense changes in topographic feature depths independent of adsorbed proteins localized along ridge edges and tops. However, our data also suggests a strong combinatory effect of topography with culture medium composition, and also a cell type dependency in determining the level of cell elongation and alignment to nanoscale topographic features. PMID:18041718

  6. Sub-micron Polymer–Zeolitic Imidazolate Framework Layered Hybrids via Controlled Chemical Transformation of Naked ZnO Nanocrystal Films

    Energy Technology Data Exchange (ETDEWEB)

    Meckler, Stephen M.; Li, Changyi; Queen, Wendy L.; Williams, Teresa E.; Long, Jeffrey R.; Buonsanti, Raffaella; Milliron, Delia J.; Helms, Brett A.

    2015-11-24

    Here we show that sub-micron coatings of zeolitic imidazolate frameworks (ZIFs) and even ZIF–ZIF bilayers can be grown directly on polymers of intrinsic microporosity from zinc oxide (ZnO) nanocrystal precursor films, yielding a new class of all-microporous layered hybrids. The ZnO-to-ZIF chemical transformation proceeded in less than 30 min under microwave conditions using a solution of the imidazole ligand in N,N-dimethylformamide (DMF), water, or mixtures thereof. By varying the ratio of DMF to water, it was possible to control the morphology of the ZIF-on-polymer from isolated crystallites to continuous films. Grazing incidence X-ray diffraction was used to confirm the presence of crystalline ZIF in the thin films, and X-ray absorption spectroscopy was used to quantify film purity, revealing films with little to no residual ZnO. The role solvent plays in the transformation mechanism is discussed in light of these findings, which suggest the ZnO nanocrystals may be necessary to localize heterogeneous nucleation of the ZIF to the polymer surface.

  7. Sub-micron Polymer–Zeolitic Imidazolate Framework Layered Hybrids via Controlled Chemical Transformation of Naked ZnO Nanocrystal Films

    Energy Technology Data Exchange (ETDEWEB)

    Meckler, Stephen M.; Li, Changyi; Queen, Wendy L. [Department; Williams, Teresa E.; Long, Jeffrey R.; Buonsanti, Raffaella; Milliron, Delia J. [McKetta; Helms, Brett A.

    2015-11-02

    Here we show that sub-micron coatings of zeolitic imidazolate frameworks (ZIFs) and even ZIF–ZIF bilayers can be grown directly on polymers of intrinsic microporosity from zinc oxide (ZnO) nanocrystal precursor films, yielding a new class of all-microporous layered hybrids. The ZnO-to-ZIF chemical transformation proceeded in less than 30 min under microwave conditions using a solution of the imidazole ligand in N,N-dimethylformamide (DMF), water, or mixtures thereof. By varying the ratio of DMF to water, it was possible to control the morphology of the ZIF-on-polymer from isolated crystallites to continuous films. Grazing incidence X-ray diffraction was used to confirm the presence of crystalline ZIF in the thin films, and X-ray absorption spectroscopy was used to quantify film purity, revealing films with little to no residual ZnO. The role solvent plays in the transformation mechanism is discussed in light of these findings, which suggest the ZnO nanocrystals may be necessary to localize heterogeneous nucleation of the ZIF to the polymer surface.

  8. Effects of digestion protocols on the isolation and characterization of metal-metal wear particles. I. Analysis of particle size and shape.

    Science.gov (United States)

    Catelas, I; Bobyn, J D; Medley, J B; Krygier, J J; Zukor, D J; Petit, A; Huk, O L

    2001-06-05

    Isolation of metal wear particles from hip simulator lubricants or tissues surrounding implants is a challenging problem because of small particle size, their tendency to agglomerate, and their potential for chemical degradation by digestion reagents. To provide realistic measurements of size, shape, and composition of metal wear particles, it is important to optimize particle isolation and minimize particle changes due to the effects of the reagents. In this study (Part I of II), transmission electron microscopy (TEM) was used to examine and compare the effects of different isolation protocols, using enzymes or alkaline solutions, on the size and shape of three different types of cobalt-based alloy particles produced from metal-metal bearings. The effect on particle composition was examined in a subsequent study (Part II). Large particles (particles (particle size and to a lesser extent particle shape. For both large particles and small particles generated in water, the changes in size were more extensive after alkaline than after enzymatic protocols and increased with alkaline concentration and time in solution, up to twofold at 2 h and threefold at 48 h. However, when isolating particles from 95% serum, an initial protective effect of serum proteins and/or lipids was observed. Because of this protective effect, there was no significant difference in particle size and shape for both oval and needle-shaped particles after 2 h in 2N KOH and after enzymatic treatments. However, round particles were significantly smaller after 2 h in 2N KOH than after enzymatic treatments. Particle composition may also have been affected by the 2N KOH treatment, as suggested by a difference in particle contrast under TEM, an issue examined in detail in Part II. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 55: 320-329, 2001

  9. Hydrogen absorption induced metal deposition on palladium and palladium-alloy particles

    Science.gov (United States)

    Wang, Jia X [East Setauket, NY; Adzic, Radoslav R [East Setauket, NY

    2009-03-24

    The present invention relates to methods for producing metal-coated palladium or palladium-alloy particles. The method includes contacting hydrogen-absorbed palladium or palladium-alloy particles with one or more metal salts to produce a sub-monoatomic or monoatomic metal- or metal-alloy coating on the surface of the hydrogen-absorbed palladium or palladium-alloy particles. The invention also relates to methods for producing catalysts and methods for producing electrical energy using the metal-coated palladium or palladium-alloy particles of the present invention.

  10. Modelling of non-metallic particles motion process in foundry alloys

    Directory of Open Access Journals (Sweden)

    P. L. Żak

    2015-04-01

    Full Text Available The behaviour of non-metallic particles in the selected composites was analysed, in the current study. The calculations of particles floating in liquids differing in viscosity were performed. Simulations based on the Stokes equation were made for spherical SiC particles and additionally the particle size influence on Reynolds number was analysed.The movement of the particles in the liquid metal matrix is strictly connected with the agglomerate formation problem.Some of collisions between non-metallic particles lead to a permanent connection between them. Creation of the two spherical particles and a metallic phase system generates the adhesion force. It was found that the adhesion force mainly depends on the surface tension of the liquid alloy and radius of non-metallic particles.

  11. Nano-analyses of wear particles from metal-on-metal and non-metal-on-metal dual modular neck hip arthroplasty.

    Science.gov (United States)

    Xia, Zhidao; Ricciardi, Benjamin F; Liu, Zhao; von Ruhland, Christopher; Ward, Mike; Lord, Alex; Hughes, Louise; Goldring, Steven R; Purdue, Edward; Murray, David; Perino, Giorgio

    2017-04-01

    Increased failure rates due to metallic wear particle-associated adverse local tissue reactions (ALTR) is a significant clinical problem in resurfacing and total hip arthroplasty. Retrieved periprosthetic tissue of 53 cases with corrosion/conventional metallic wear particles from 285 revision operations for ALTR was selected for nano-analyses. Three major classes of hip implants associated with ALTR, metal-on-metal hip resurfacing arthroplasty (MoM HRA) and large head total hip replacement (MoM LHTHA) and non-metal-on-metal dual modular neck total hip replacement (Non-MoM DMNTHA) were included. The size, shape, distribution, element composition, and crystal structure of the metal particles were analyzed by conventional histological examination and electron microscopy with analytic tools of 2D X-ray energy dispersive spectrometry and X-ray diffraction. Distinct differences in size, shape, and element composition of the metallic particles were detected in each implant class which correlate with the histological features of severity of ALTR and variability in implant performance. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Ultrafast microwave hydrothermal synthesis and characterization of Bi1-xLaxFeO3sub> micronized particles

    DEFF Research Database (Denmark)

    Ponzoni, C.; Cannio, M.; Boccaccini, Dino

    2015-01-01

    In this work a microwave assisted hydrothermal method is applied to successfully synthesize lanthanum doped bismuth ferrites (BLFO, Bi1-xLaxFeO3 where x = 0, 0.15, 0.30 and 0.45). The growth mechanism of the Bi1-xLaxFeO3 crystallites is discussed in detail. The existence of the single-phase perov...... temperature for pure BiFeO3 and Bi0,83La0.15FeO3. The results indicate that the materials are both weakly ferromagnetic, with no significant hysteresis in the curves. (C) 2015 Elsevier B.V. All rights reserved....

  13. Characteristics of metals in nano/ultrafine/fine/coarse particles collected beside a heavily trafficked road.

    Science.gov (United States)

    Lin, Chih-Chung; Chen, Shui-Jen; Huang, Kuo-Lin; Hwang, Wen-Ing; Chang-Chien, Guo-Ping; Lin, Wen-Yinn

    2005-11-01

    Fine particles emitted from vehicles have adverse health effects because of their sizes and chemical compositions. Therefore, this study attempted to characterize the metals in nano (0.010 Nano-MOUDI. The nano particles were found to contain more of traffic-related metals (Pb, Cd, Cu, Zn, Ba, and Ni) than particles of other sizes, although crustal metals accounted for over 90% of all the particulate metals. Most crustal metals, Ba, Ni, Pb, and Zn in ultrafine particles displayed Aitken modes due to their local origins. The Ag, Cd, Cr, Ni, Pb, Sb, V, and Zn were 37, 50, 28, 30, 24, 64, 38, and 22% by mass, respectively, in nano particles were strongly associated with diesel fuel, while the Cu, Mn, and Sr in particles nano particles, more associated with diesel soot than with gasoline exhaust, is another health concern.

  14. Functional Role of Infective Viral Particles on Metal Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Coates, John D.

    2014-04-01

    A proposed strategy for the remediation of uranium (U) contaminated sites was based on the immobilization of U by reducing the oxidized soluble U, U(VI), to form a reduced insoluble end product, U(IV). Previous studies identified Geobacter sp., including G. sulfurreducens and G. metallireducens, as predominant U(VI)-reducing bacteria under acetate-oxidizing and U(VI)-reducing conditions. Examination of the finished genome sequence annotation of the canonical metal reducing species Geobacter sulfurreducens strain PCA and G. metallireduceans strain GS-15 as well as the draft genome sequence of G. uraniumreducens strain Rf4 identified phage related proteins. In addition, the completed genome for Anaeromyxobacter dehalogenans and the draft genome sequence of Desulfovibrio desulfuricans strain G20, two more model metal-reducing bacteria, also revealed phage related sequences. The presence of these gene sequences indicated that Geobacter spp., Anaeromyxobacter spp., and Desulfovibrio spp. are susceptible to viral infection. Furthermore, viral populations in soils and sedimentary environments in the order of 6.4×10{sup 6}–2.7×10{sup 10} VLP’s cm{sup -3} have been observed. In some cases, viral populations exceed bacterial populations in these environments suggesting that a relationship may exist between viruses and bacteria. Our preliminary screens of samples collected from the ESR FRC indicated that viral like particles were observed in significant numbers. The objective of this study was to investigate the potential functional role viruses play in metal reduction specifically Fe(III) and U(VI) reduction, the environmental parameters affecting viral infection of metal reducing bacteria, and the subsequent effects on U transport.

  15. Mathematical Modeling of the Melting Rate of Metallic Particles in the Electric Arc Furnace

    National Research Council Canada - National Science Library

    González, O. J. P; Ramírez-Argáez, Marco A; Conejo, A. N

    2010-01-01

    A computational fluid dynamics model coupled to a lagrangian model of melting/solidifying particles has been developed to describe the melting kinetics of metallic particles in an industrial Electric Arc Furnace (EAF...

  16. Introducing asymmetric functionality into MOFs via the generation of metallic Janus MOF particles.

    Science.gov (United States)

    Ayala, Abraham; Carbonell, Carlos; Imaz, Inhar; Maspoch, Daniel

    2016-04-14

    Herein we report a versatile methodology for engineering metallic Janus MOF particles based on desymmetrization at interfaces, whereby each MOF particle is partially coated with a desired metal. We demonstrate that it enables the fabrication of homogeneous Janus MOF particles according to the MOF (ZIF-8, UiO-66 or UiO-66-SH), the metal (Au, Co or Pt), the MOF particle size (from the micrometer to the submicrometer regime) and the metal-film thickness (from 5 nm to 50 nm) employed. We anticipate that our strategy could be applied to impart new functionalities to MOFs, including asymmetric functionalization, magnetic-guidance and motorization.

  17. Non ideal detonation of emulsion explosives mixed with metal particles

    Science.gov (United States)

    Mendes, Ricardo; Ribeiro, José B.; Plaksin, I.; Campos, Jose

    2012-03-01

    The detonation of ammonium nitrate based compositions like emulsion explosives mixed with metal particles was experimentally investigated. Aluminum powder with a mean particle size of 6 μm was used, and the mass concentration of aluminum on the explosive charge ranged from 0 to 30% wt. The values of the detonation velocity, the pressure attenuation - P(x) - of the shock front amplitude in a standard PMMA monitor and manganin gauges pressure-time histories are shown as a function of the explosive charge porosity and specific mass. All these parameters except the pressuretimes histories have been evaluated using the multi-fiber optical probe (MFOP) method which is based on the use of an optical fiber strip, with 64 independent optical fibers. The MFOP allows a quasicontinuous evaluation of the detonation wave run propagation and the assessment of spatial resolved measurements of the shock wave induced in the PMMA barrier. Results of that characterization process are presented and discussed for aluminized and non-aluminized emulsion explosives. The experimental results have shown that the detonation velocity decreases monotonically with the increase of aluminum content. Nevertheless the peak of detonation pressure profiles presents a non-monotonic behavior increasing its value up to an Al content of 20% wt, after which it starts to decrease.

  18. Non ideal detonation of emulsion explosives mixed with metal particles

    Science.gov (United States)

    Mendes, R.; Ribeiro, J.; Plaksin, I.; Campos, J.

    2011-06-01

    The detonation of ammonium nitrate based compositions like emulsion explosives (EX) mixed with metal particles has been investigated experimentally. Aluminium powder with a mean particle size of 10 μm was used, and the mass concentration of aluminum on the explosive charge was ranged from 0 to 30%. The values of the detonation velocity, the pressure attenuation - P(x) - of detonation front amplitude in a standard PMMA monitor and manganin gauges pressure-time histories are shown as a function of the explosive charge porosity and specific mass. All these parameters except the pressure-times histories have been evaluated using the multi fiber optical probe (MFOP) method which is based on the use of an optical fiber strip, with 64 independent optical fibers. The MFOP allow a quasi continuous evaluation of the detonation wave run propagation and the assessment to spatial resolved measurements of the shock wave induced in the PMMA barrier which in turns allows a detailed characterization of the detonation reaction zone structure. Results of that characterization process are presented and discussed for aluminized and non aluminized EX. Moreover, the effect of the mass concentration of the sensitizing agent (hollow glass micro-balloons) on the non monotonic detonation velocity variation, for EX, will be discussed.

  19. Metal nanocrystals incorporated within pH-responsive microgel particles

    Science.gov (United States)

    Vamvakaki, Maria; Palioura, D.; Anastasiadis, S. H.; Armes, S. P.

    2007-03-01

    Cross-linked latexes of approximately 250 nm in diameter are synthesized by emulsion polymerization of 2-(diethylamino)ethyl methacrylate using a PEO-based macromonomer as the stabilizer at pH 9. These particles exhibit reversible swelling properties in water by adjusting the solution pH: at low pH they exist as swollen microgels due to protonation of the tertiary amine units whereas deswelling occurs above pH 7. The swollen microgels can be used as nanoreactors for the in situ synthesis of Pt nanoparticles. The effects of the method of Pt nanoparticle formation on the size of the microgel particles are studied by DLS. Polymer-metal interactions are investigated by UV-visible absorption spectroscopy, which confirms that the Pt salt is completely reduced to zero-valent Pt using NaBH4. TEM and XRD verify the formation of nanometer-sized Pt nanocrystals within the microgels, which can be used as recoverable colloidal catalyst supports for various organic reactions.

  20. Characterization of typical metal particles during haze episodes in Shanghai, China.

    Science.gov (United States)

    Li, Rui; Yang, Xin; Fu, Hongbo; Hu, Qingqing; Zhang, Liwu; Chen, Jianmin

    2017-08-01

    Aerosol particles were collected during three heavy haze episodes at Shanghai in the winter of 2013. Transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy was used to study the morphology and speciation of typical metal particles at a single-particle level. In addition, time-of-flight aerosol mass spectrometry (ATOFMS) was applied to identify the speciation of the Fe-containing particles. TEM analysis indicated that various metal-containing particles were hosted by sulfates, nitrates, and oxides. Fe-bearing particles mainly originated from vehicle emissions and/or steel production. Pb-, Zn-, and Sb-bearing particles were mainly contributed by anthropogenic sources. Fe-bearing particles were clustered into six groups by ATOFMS: Fe-Carbon, Fe-Inorganic, Fe-Trace metal, Fe-CN, Fe-PO3, and Fe-NO3. ATOFMS data suggested that Fe-containing particles corresponded to different origins, including industrial activities, resuspension of dusts, and vehicle emissions. Fe-Carbon and Fe-CN particles displayed significant diurnal variation, and high levels were observed during the morning rush hours. Fe-Inorganic and Fe-Trace metal particle levels peaked at night. Furthermore, Fe-Carbon and Fe-PO3 were mainly concentrated in the fine particles. Fe-CN, Fe-Inorganic, and Fe-Trace metal exhibited bimodal distribution. The mixing state of the particles revealed that all Fe-bearing particles tended to be mixed with sulfate and nitrate. The data presented herein is essential for elucidating the origin, evolution processes, and health effects of metal-bearing particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Aptamer functionalized noble metal particles for bioanalytical and biomedical applications

    Science.gov (United States)

    Yasun, Emir

    Noble metal particles, especially gold (Au) and silver (Ag) have been exploited in a broad range of biological applications due to their unique intrinsic features that depend on their physical appearance or optoelectronic properties, which can be tuned with the change in the size or shape of those particles. Thus, this tunability enables gold nanoparticles (AuNPs) to be used in biomedical diagnostic and therapeutical applications. In photothermal therapy applications, nanomaterials, which can absorb efficiently in NIR region, are utilized since the healthy tissue or cells can't absorb at this spectral region. Among AuNPs, gold nanorods (AuNRs) are one of the best candidates for hyperthermia therapy of cancer cells with their high absorption cross-sections and tunable absorption maxima in NIR region. When this unique optical property is combined with the specificity against cancer cells utilized by aptamer conjugations, AuNRs become to be one of the most important nanoparticles employed in both cancer cell sensing and therapy. However, one drawback of AuNRs is having the surfactant CTAB on their surface, which can cause nonspecificity and cytotoxicity. In this research, the side effects of CTAB are passivated by BSA modification, where the nonspecificity and cytotoxicity are dramatically decreased prior to the NIR treatment. Recognition of changes in the rare cancer protein abundances can lead the early diagnosis of cancer, so capturing these low abundance proteins has a great significance. In this research, firstly, aptamer conjugated AuNRs were used to capture 1ng of a-thrombin effectively from plasma samples as model system. Then both aptamer conjugated AuNRs and silver microspheres (SMSs) are used to capture the biomarker proteins of a colon cancer cell line, DLD-1. Gold and silver surfaces can easily be modified through thiolate chemistry, compared to the tedious modification steps for the magnetic particles, so more aptamer immobilization can be achieved for

  2. The Influence of Particle Shapes on Strength and Damage Properties of Metal Matrix Composites.

    Science.gov (United States)

    Qing, Hai

    2015-08-01

    The influence of the distribution of particle shapes, locations and orientations on the mechanical behavior of the particle reinforced Metal-Matrix Composite (MMC) is studied through finite element (FE) method under different loading conditions in this investigation. The FE-model with multi-particle is generated through the random sequential adsorption algorithm, with the particles treated respectively as elastic-brittle circular, regular octagon and hexagon and square shape. Ductile failure in metal matrix, brittle fracture of particles and interface debonding are taken into account during the simulations. 2D cohesive element is applied to simulate the debonding behavior of interface. The damage models based on the stress triaxial indicator and maximum principal stress criterion are developed to simulate the ductile failure of metal matrix and brittle cracking of particles, respectively. Simulation results show that the interface debonding dominates the failure process under the loading, while the damage in particle grows at slowest rate compared with those in matrix and interface.

  3. Characterisation of a metal matrix composite produced with laser particle injection

    NARCIS (Netherlands)

    Kloosterman, AB; De Hosson, JTM; Sudarshan, TS; Jeandin, M; Khor, KA

    1998-01-01

    This paper concentrates on the laser particle injection process. TiC, TiN end SiC particles were injected into Ti-6Al-4V, which resulted in the formation of a metal matrix composite with modest dissolution of the added particles. The laser tracks with SIC exhibited a diversity of microstructures

  4. Channeling and electromagnetic radiation of relativistic charged particles in metal-organic frameworks

    Science.gov (United States)

    Zhevago, N. K.; Glebov, V. I.

    2017-06-01

    We have developed the theory of electromagnetic interaction of relativistic charged particles with metal-organic frameworks (MOFs). The electrostatic potential and electron number density distribution in MOFs were calculated using the most accurate data for the atomic form factors. Peculiarities of axial channeling of fast charged particles and various types of electromagnetic radiation from relativistic particles has been discussed.

  5. Identifying airborne metal particles sources near an optoelectronic and semiconductor industrial park

    Science.gov (United States)

    Chen, Ho-Wen; Chen, Wei-Yea; Chang, Cheng-Nan; Chuang, Yen-Hsun; Lin, Yu-Hao

    2016-06-01

    The recently developed Central Taiwan Science Park (CTSP) in central Taiwan is home to an optoelectronic and semiconductor industrial cluster. Therefore, exploring the elemental compositions and size distributions of airborne particles emitted from the CTSP would help to prevent pollution. This study analyzed size-fractionated metal-rich particle samples collected in upwind and downwind areas of CTSP during Jan. and Oct. 2013 by using micro-orifice uniform deposited impactor (MOUDI). Correlation analysis, hierarchical cluster analysis and particle mass-size distribution analysis are performed to identify the source of metal-rich particle near the CTSP. Analyses of elemental compositions and particle size distributions emitted from the CTSP revealed that the CTSP emits some metals (V, As, In Ga, Cd and Cu) in the ultrafine particles (< 1 μm). The statistical analysis combines with the particle mass-size distribution analysis could provide useful source identification information. In airborne particles with the size of 0.32 μm, Ga could be a useful pollution index for optoelectronic and semiconductor emission in the CTSP. Meanwhile, the ratios of As/Ga concentration at the particle size of 0.32 μm demonstrates that humans near the CTSP would be potentially exposed to GaAs ultrafine particles. That is, metals such as Ga and As and other metals that are not regulated in Taiwan are potentially harmful to human health.

  6. Processes of conversion of a hot metal particle into aerogel through clusters

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B. M., E-mail: bmsmirnov@gmail.com [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2015-10-15

    Processes are considered for conversion into a fractal structure of a hot metal micron-size particle that is located in a buffer gas or a gas flow and is heated by an external electric or electromagnetic source or by a plasma. The parameter of this heating is the particle temperature, which is the same in the entire particle volume because of its small size and high conductivity. Three processes determine the particle heat balance: particle radiation, evaporation of metal atoms from the particle surface, and heat transport to the surrounding gas due to its thermal conductivity. The particle heat balance is analyzed based on these processes, which are analogous to those for bulk metals with the small particle size, and its high temperature taken into account. Outside the particle, where the gas temperature is lower than on its surface, the formed metal vapor in a buffer gas flow is converted into clusters. Clusters grow as a result of coagulation until they become liquid, and then clusters form fractal aggregates if they are removed form the gas flow. Subsequently, associations of fractal aggregates join into a fractal structure. The rate of this process increases in medium electric fields, and the formed fractal structure has features of aerogels and fractal fibers. As a result of a chain of the above processes, a porous metal film may be manufactured for use as a filter or catalyst for gas flows.

  7. Submicron particles of Co, Ni and Co–Ni alloys

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 24; Issue 5 ... Magnetic Materials Volume 24 Issue 5 October 2001 pp 515-521 ... Magnetic sub-micron sized particles (with diameters in the range 100–600 nm) of Co, Ni and Co–Ni alloys, protected with polyvinylpyrrolidone have been prepared in gram quantities ...

  8. Metal particles in a ceramic matrix--scanning electron microscopy and transmission electron microscopy characterization.

    Science.gov (United States)

    Konopka, K

    2006-09-01

    This paper is concerned with ceramic matrix (Al(2)O(3)) composites with introduced metal particles (Ni, Fe). The composites were obtained via sintering of powders under very high pressure (2.5 GPa). Scanning electron microscopy and transmission electron microscopy were chosen as the tools for the identification and description of the shape, size and distribution of the metal particles. The Al(2)O(3)-Ni composite contained agglomerates of the Ni particles surrounded by ceramic grains and nanometre-size Ni particles located inside the ceramic grains and at the ceramic grain boundaries. In the Al(2)O(3)-Fe composite, the Fe particles were mostly surrounded by ceramic grains. Moreover, holes left by the Fe particles were found. The high pressure used in the fabrication of the composites changed the shape of the metal and ceramic powder grains via plastic deformation.

  9. FDTD approach to optical forces of tightly focused vector beams on metal particles.

    Science.gov (United States)

    Qin, Jian-Qi; Wang, Xi-Lin; Jia, Ding; Chen, Jing; Fan, Ya-Xian; Ding, Jianping; Wang, Hui-Tian

    2009-05-11

    We propose an improved FDTD method to calculate the optical forces of tightly focused beams on microscopic metal particles. Comparison study on different kinds of tightly focused beams indicates that trapping efficiency can be altered by adjusting the polarization of the incident field. The results also show the size-dependence of trapping forces exerted on metal particles. Transverse tapping forces produced by different illumination wavelengths are also evaluated. The numeric simulation demonstrates the possibility of trapping moderate-sized metal particles whose radii are comparable to wavelength.

  10. Tailored microstructure of colloidal lipid particles for Pickering emulsions with tunable properties

    NARCIS (Netherlands)

    Schroder, Anja; Sprakel, Joris; Schroën, Karin; Berton-Carabin, Claire C.

    2017-01-01

    Sub-micron colloidal lipid particles (CLPs) can successfully be used as Pickering stabilizers in oil-in-water (O/W) emulsions, leading to an enhanced physical stability compared to conventional emulsifier-stabilized emulsions. Varying the lipid solid-liquid ratio leads to particles with distinct

  11. Application of vacuum metallurgy to separate pure metal from mixed metallic particles of crushed waste printed circuit board scraps.

    Science.gov (United States)

    Zhan, Lu; Xu, Zhenming

    2008-10-15

    The principle of separating pure metal from mixed metallic particles (MMPs) byvacuum metallurgy is that the vapor pressures of various metals at the same temperature are different As a result, the metal with high vapor pressure and low boiling point can be separated from the mixed metals through distillation or sublimation, and then it can be recycled through condensation under a certain condition. The vacuum metallurgy separation (VMS) of MMPs of crushed waste printed circuit boards (WPCBs) has been studied in this paper. Theoretical analyses show that the MMPs (copper, zinc, bismuth, lead, and indium, for example) can be separated by vacuum metallurgy. The copper particles (0.15-0.20 mm) and zinc particles (<0.30 mm) were chosen to simulate the MMPs of crushed WPCBs. Experimental results show that the separated efficiency of zinc in the copper-rich particles achieves 96.19 wt % when the vacuum pressure is 0.01-0.10 Pa, the heating temperature is 1123 K, and the heating time is 105 min. Under this operation condition, the separated efficiency of zinc in the copper-rich particles from crushed WPCBs achieves 97.00 wt % and the copper purity increases from 90.68 to 99.84 wt %.

  12. Single crystal particles of a mesoporous mixed transition metal oxide with a wormhole structure.

    Science.gov (United States)

    Lee, B; Lu, D; Kondo, J N; Domen, K

    2001-10-21

    A new type of mesoporous mixed transition metal oxide of Nb and Ta (NbTa-TIT-1) has been prepared through a two-step calcination, which consists of single crystal particles with wormhole mesoporous structure.

  13. Nonisothermal particle modeling of municipal solid waste combustion with heavy metal vaporization

    Energy Technology Data Exchange (ETDEWEB)

    Mazza, G. [Facultad de Ingenieria, Departamento de Quimica, Universidad Nacional del Comahue, IDEPA (CONICET - UNCo), Buenos Aires 1400, 8300 Neuquen (Argentina); Falcoz, Q.; Gauthier, D.; Flamant, G. [Laboratoire Procedes et Materiaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu Cedex (France); Soria, J. [Facultad de Ingenieria, Departamento de Quimica, Universidad Nacional del Comahue, IDEPA (CONICET - UNCo), Buenos Aires 1400, 8300 Neuquen (Argentina); Laboratoire Procedes et Materiaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu Cedex (France)

    2010-12-15

    A particulate model was developed for municipal solid-waste incineration in a fluidized bed combining solid-waste-particle combustion and heavy metal vaporization from the burning particles. Based on a simpler, isothermal version presented previously, this model combines an asymptotic-combustion model for carbonaceous-solid combustion and a shrinking-core model to describe the heavy metal vaporization phenomenon, in which the particle is now considered nonisothermal. A parametric study is presented that shows the influence of temperature on the global metal-vaporization process. The simulation results are compared to experimental data obtained with a lab-scale fluid bed incinerator and to the results of the simpler isothermal model. It is shown that conduction in the particle strongly affects the variation of the vaporization rate with time and that the present version of the model well fits both the shape of the plots and the maximum heavy metal vaporization rates for all bed temperatures. (author)

  14. An approach to calculating metal particle detection in lubrication oil based on a micro inductive sensor

    Science.gov (United States)

    Wu, Yu; Zhang, Hongpeng

    2017-12-01

    A new microfluidic chip is presented to enhance the sensitivity of a micro inductive sensor, and an approach to coil inductance change calculation is introduced for metal particle detection in lubrication oil. Electromagnetic knowledge is used to establish a mathematical model of an inductive sensor for metal particle detection, and the analytic expression of coil inductance change is obtained by a magnetic vector potential. Experimental verification is carried out. The results show that copper particles 50–52 µm in diameter have been detected; the relative errors between the theoretical and experimental values are 7.68% and 10.02% at particle diameters of 108–110 µm and 50–52 µm, respectively. The approach presented here can provide a theoretical basis for an inductive sensor in metal particle detection in oil and other areas of application.

  15. Atomistic theory of Ostwald ripening and disintegration of supported metal particles under reaction conditions.

    Science.gov (United States)

    Ouyang, Runhai; Liu, Jin-Xun; Li, Wei-Xue

    2013-02-06

    Understanding Ostwald ripening and disintegration of supported metal particles under operating conditions has been of central importance in the study of sintering and dispersion of heterogeneous catalysts for long-term industrial implementation. To achieve a quantitative description of these complicated processes, an atomistic and generic theory taking into account the reaction environment, particle size and morphology, and metal-support interaction is developed. It includes (1) energetics of supported metal particles, (2) formation of monomers (both the metal adatoms and metal-reactant complexes) on supports, and (3) corresponding sintering rate equations and total activation energies, in the presence of reactants at arbitrary temperature and pressure. The thermodynamic criteria for the reactant assisted Ostwald ripening and induced disintegration are formulated, and the influence of reactants on sintering kinetics and redispersion are mapped out. Most energetics and kinetics barriers in the theory can be obtained conveniently by first-principles theory calculations. This allows for the rapid exploration of sintering and disintegration of supported metal particles in huge phase space of structures and compositions under various reaction environments. General strategies of suppressing the sintering of the supported metal particles and facilitating the redispersions of the low surface area catalysts are proposed. The theory is applied to TiO(2)(110) supported Rh particles in the presence of carbon monoxide, and reproduces well the broad temperature, pressure, and particle size range over which the sintering and redispersion occurred in such experiments. The result also highlights the importance of the metal-carbonyl complexes as monomers for Ostwald ripening and disintegration of supported metal catalysts in the presence of CO.

  16. Electrochemical method for synthesizing metal-containing particles and other objects

    Science.gov (United States)

    Rondinone, Adam Justin; Ivanov, Ilia N.; Smith, Sean Campbell; Liang, Chengdu; Hensley, Dale K.; Moon, Ji-Won; Phelps, Tommy Joe

    2017-05-02

    The invention is directed to a method for producing metal-containing (e.g., non-oxide, oxide, or elemental) nano-objects, which may be nanoparticles or nanowires, the method comprising contacting an aqueous solution comprising a metal salt and water with an electrically powered electrode to form said metal-containing nano-objects dislodged from the electrode, wherein said electrode possesses a nanotextured surface that functions to confine the particle growth process to form said metal-containing nano-objects. The invention is also directed to the resulting metal-containing compositions as well as devices in which they are incorporated.

  17. Stabilization of Heavy Metal Particles in AL2O3-W Suspensions

    Directory of Open Access Journals (Sweden)

    Kędzierska – Sar A.

    2016-09-01

    Full Text Available Ceramic – metal composites are widely used materials in a whole world. There were invented many fabrication methods for those kind of materials, but still exists some problems which need to be fixed. Stability of high density metal particles (e.g. W, Mo, Nb in ceramic-metal composite suspensions is one of crucial issues to be solved in order to obtain homogenous composite material with desired properties such as high fracture toughness, mechanical strength, hardness, wear resistance.

  18. Effect of erodent particles on the erosion of metal specimens

    Energy Technology Data Exchange (ETDEWEB)

    Razzaque, M. Mahbubur, E-mail: mmrazzaque@me.buet.ac.bd; Alam, M. Khorshed; Khan, M. Ishak, E-mail: ishak.buet@gmail.com [Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET), Dhaka (Bangladesh)

    2016-07-12

    This paper presents the experimental results of the measurement of erosion rate of carbon steel specimens in sand water slurry system in a slurry pot tester. Sylhet sand has been sieved to get three sizes of erodent particles; namely, less than 250 micron, 250 to 590 micron and 590 to 1190 micron. Experiments are done with three sand concentrations (10%, 15% and 20%). The rate of erosion of the carbon steel specimens is measured as the loss of weight per unit surface area per unit time under the dynamic action of solid particles. The eroded surfaces of the specimens are examined using Scanning Electron Microscopy (SEM) to visualize the impact of the slurry of various conditions. It is seen that irrespective of the particle size the rate of erosion increases with the increase of slurry concentration. This increment of erosion rate at high concentration is high for large particles. High erosion rate is observed in case of large sand particles. In case of small and fine particles erosion rate is small because of low impact energy as well as the wastage of energy to overcome the hindrance of the finer particles before striking on the specimen surface.

  19. Band-Like Diffusion of Charged Particles in Metals : Condensed Matter and Statistical Physics

    OpenAIRE

    Kosaku, YAMADA; Research Institute for Fundamental Physics, Kyoto University

    1986-01-01

    Diffusion coefficient for charged heavy particles in metals is obtained by taking into account the particle-electron interaction based on the Kubo formula. It is pointed out that vertex correction in the two-particle Green's function is indespensable not to violate the internal consistency. By including the vertex correction in addition to the selfenergy correction, we obtain for band-like diffusion the same temperature dependence as that for hopping-like one.

  20. Characterization of metal particles on supporting materials mordenite, ultra stable Y zeolita, and natural zeolit

    Science.gov (United States)

    Sesario, Rujito; Dwi, Khoirina; Rahmawati, Fitria; Heraldy, Eddy; Rachmadani

    2017-08-01

    This research aims to prepare, characterize, and determine the metal particles of Molybdenum (Mo) and Cobalt (Co) metal on the supporting material Mordenite, Ultra Stable Y-Zeolite (USY), and Natural Zeolite (ZAA). In this research the catalysts were prepared, activated, and characterized. The bimetallic catalysts CoMo/Mordenite, CoMo/USY, CoMo/ZAA were prepared by coimpregnation method with ratio amount of Co : Mo metals 1 : 2. Activation of the catalyst included calcination and reduction. The crystallinity was characterized using X-ray diffraction (XRD), minerals present in the catalyst was analyzed using X-Ray Fluorescence (XRF). The results based on characterization, it is known that catalyst CoMo/USY shows best amount metal impregnated (Co metal content is 0.09657 mmol/g and metal content of Mo is 0.62723 mmol/g). The CoMo/Mordenite and CoMo/USY metal particles contained of CoO, MoO3, CoMoO4, Co, Mo, and CoMo. Thus CoMo/ZAA metal particles consisted of CoO, MoO3, CoMoO4, Co, Mo, CoMo. Based on the characterization of the crystal structure and the metal content it is known that the CoMo/USY was the best sample compared to CoMo/Mordenite and CoMo/ZAA.

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

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2016-01-01

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

  2. Self Assembly of Nano Metric Metallic Particles for Realization of Photonic and Electronic Nano Transistors

    Directory of Open Access Journals (Sweden)

    Asaf Shahmoon

    2010-05-01

    Full Text Available In this paper, we present the self assembly procedure as well as experimental results of a novel method for constructing well defined arrangements of self assembly metallic nano particles into sophisticated nano structures. The self assembly concept is based on focused ion beam (FIB technology, where metallic nano particles are self assembled due to implantation of positive gallium ions into the insulating material (e.g., silica as in silicon on insulator wafers that acts as intermediary layer between the substrate and the negatively charge metallic nanoparticles.

  3. On the Concentration Dependence of Metallic Nano-Particles in Enhanced Forster Resonance Energy Transfer

    Science.gov (United States)

    Hoa, N. M.; Nhung, T. H.; Thao, T. T.; Theu, L. T.; Viet, N. A.

    2017-06-01

    The enhanced Forster resonance energy transfer is obtained in recent experiments. One of the most important experimental facts is the observed strong enhancement of donor fluorescence with increasing concentration of metallic nanoparticle acceptors in the first stage. We propose three types of energy transfer mechanisms (Forster FRET, surface SET, and Coulomb CET) and predict simple relations for their dependencies on the concentration of metallic nano-particles. The competition of these mechanisms leads to the transfer intensity dependence on the concentration dependence of metallic nano-particles. Using these assumptions, we expect and argue about the compatibility between the experimental results.

  4. Review on preparation techniques of particle reinforced metal matrix composites

    Directory of Open Access Journals (Sweden)

    HAO Bin

    2006-02-01

    Full Text Available This paper reviews the investigation status of the techniques for preparation of metal matrix composites and the research outcomes achieved recently. The mechanisms, characteristics, application ranges and levels of development of these preparation techniques are analyzed. The advantages and the disadvantages of each technique are synthetically evaluated. Lastly, the future directions of research and the prospects for the preparation techniques of metal matrix composites are forecasted.

  5. Role of carboxylate ion and metal oxidation state on the morphology ...

    Indian Academy of Sciences (India)

    Sub-micron rods and spheres of cobalt succinate sesquihydrate and iron succinate trihydrate/pentahydrate respectively have been synthesized by the reverse micellar route. These precursors are an excellent source for the synthesis of metal and metal oxide nanoparticles. Cubes of (edge length ∼ 150 nm) Fe3O4 and ...

  6. Aerosol synthesis of nano and micro-scale zero valent metal particles from oxide precursors

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM; Lesman, Zayd [UNM; Soliman, Haytham [UNM; Zea, Hugo [UNM

    2010-01-01

    In this work a novel aerosol method, derived form the batch Reduction/Expansion Synthesis (RES) method, for production of nano / micro-scale metal particles from oxides and hydroxides is presented. In the Aerosol-RES (A-RES) method, an aerosol, consisting of a physical mixture of urea and metal oxide or hydroxides, is passed through a heated oven (1000 C) with a residence time of the order of 1 second, producing pure (zero valent) metal particles. It appears that the process is flexible regarding metal or alloy identity, allows control of particle size and can be readily scaled to very large throughput. Current work is focused on creating nanoparticles of metal and metal alloy using this method. Although this is primarily a report on observations, some key elements of the chemistry are clear. In particular, the reducing species produced by urea decomposition are the primary agents responsible for reduction of oxides and hydroxides to metal. It is also likely that the rapid expansion that takes place when solid/liquid urea decomposes to form gas species influences the final morphology of the particles.

  7. Metal-Particle-Decorated ZnO Nanocrystals: Photocatalysis and Charge Dynamics.

    Science.gov (United States)

    Lin, Wei-Hao; Chiu, Yi-Hsuan; Shao, Pao-Wen; Hsu, Yung-Jung

    2016-12-07

    Understanding of charge transfer processes is determinant to the performance optimization for semiconductor photocatalysts. As a representative model of composite photocatalysts, metal-particle-decorated ZnO has been widely employed for a great deal of photocatalytic applications; however, the dependence of charge carrier dynamics on the metal content and metal composition and their correlation with the photocatalytic properties have seldom been reported. Here, the interfacial charge dynamics for metal-decorated ZnO nanocrystals were investigated and their correspondence with the photocatalytic properties was evaluated. The samples were prepared with a delicate antisolvent approach, in which ZnO nanocrystals were grown along with metal particle decoration in a deep eutectic solvent. By modulating the experimental conditions, the metal content (from 0.6 to 2.3 at%) and metal composition (including Ag, Au, and Pd) in the resulting metal-decorated ZnO could be readily controlled. Time-resolved photoluminescence spectra showed that an optimal Au content of 1.3 at% could effectuate the largest electron transfer rate constant for Au-decorated ZnO nanocrystals, in conformity with the highest photocatalytic efficiency observed. The relevance of charge carrier dynamics to the metal composition was also inspected and realized in terms of the energy level difference between ZnO and metal. Among the three metal-decorated ZnO samples tested, ZnO-Pd displayed the highest photocatalytic activity, fundamentally according with the largest electron transfer rate constant deduced in carrier dynamics measurements. The current work was the first study to present the correlations among charge carrier dynamics, metal content, metal composition, and the resultant photocatalytic properties for semiconductor/metal heterostructures. The findings not only helped to resolve the standing issues regarding the mechanistic foundation of photocatalysis but also shed light on the intelligent design

  8. A study of the effect of solid particle impact and particle shape on the erosion morphology of ductile metals

    Science.gov (United States)

    Rao, P. V.; Young, S. G.; Buckley, D. H.

    1984-01-01

    Impulsive versus steady jet impingement of spherical glass bead particles on metal surfaces was studied using a gas gun facility and a commercial sand blasting apparatus. Crushed glass particles were also used in the sand blasting apparatus as well as glass beads. Comparisons of the different types of erosion patterns were made. Scanning electron microscopy, surface profilometry and energy dispersive X-ray spectroscopy analysis were used to characterize erosion patterns. The nature of the wear can be divided into cutting and deformation, each with its own characteristic features. Surface chemistry analysis indicates the possiblity of complex chemical and/or mechanical interactions between erodants and target materials.

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

    Science.gov (United States)

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

    2017-12-01

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

  10. Bio-Functional, Lanthanide-Labeled Polymer Particles by Seeded Emulsion Polymerization and their Characterization by Novel ICP-MS Detection.

    Science.gov (United States)

    Thickett, Stuart C; Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A

    2010-01-01

    We present the synthesis and characterization of monodisperse, sub-micron poly(styrene) (PS) particles loaded with up to and including 10(7) lanthanide (Ln) ions per particle. These particles have been synthesized by seeded emulsion polymerization with a mixture of monomer and a pre-formed Ln complex, and analyzed on a particle-by-particle basis by a unique inductively coupled plasma mass cytometer. Seed particles were prepared by surfactant-free emulsion polymerization (SFEP) to obtain large particle sizes in aqueous media. Extensive surface acid functionality was introduced using the acid-functional initiator ACVA, either during seed latex synthesis or in the second stage of polymerization. The loading of particles with three different Ln ions (Eu, Tb, and Ho) has proven to be close to 100 % efficient on an individual and combined basis. Covalent attachment of metal-tagged peptides and proteins such as Neutravidin to the particle surface was shown to be successful and the number of bound species can be readily determined. We believe these particles can serve as precursors for multiplexed, bead-based bio-assays utilizing mass cytometric detection.

  11. Catalytic Metal Free Production of Large Cage Structure Carbon Particles: A Candidate for Hydrogen Storage

    Science.gov (United States)

    Kimura, Yuki; Nuth, Joseph A., III; Ferguson, Frank T.

    2005-01-01

    We will demonstrate that carbon particles consisting of large cages can be produced without catalytic metal. The carbon particles were produced in CO gas as well as by introduction of 5% methane gas into the CO gas. The gas-produced carbon particles were able to absorb approximately 16.2 wt% of hydrogen. This value is 2.5 times higher than the 6.5 wt% goal for the vehicular hydrogen storage proposed by the Department of Energy in the USA. Therefore, we believe that this carbon particle is an excellent candidate for hydrogen storage for fuel cells.

  12. The fate of heavy metals during combustion and gasification of contaminated biomass—A brief review

    Energy Technology Data Exchange (ETDEWEB)

    Nzihou, Ange, E-mail: ange.nzihou@mines-albi.fr [Université de Toulouse, Mines Albi, CNRS, Centre RAPSODEE, Campus Jarlard, F-81013 Albi cedex 09 (France); Stanmore, Brian [Formerly of the University of Queensland, Brisbane, QLD 4072 (Australia)

    2013-07-15

    Highlights: ► A review on metal behaviour during the thermal treatment of contamined biomass. ► Wide range of biomass waste reported. ► Distribution of metals in the ash, and in the sub-micron particles discussed. -- Abstract: The literature on the presence of heavy metals in contaminated wastes is reviewed. Various categories of materials produced from domestic and industrial activities are included, but municipal solid waste, which is a more complex material, is excluded. This review considers among the most abundant the following materials – wood waste including demolition wood, phytoremediation scavengers and chromated copper arsenate (CCA) timber, sludges including de-inking sludge and sewage sludge, chicken litter and spent pot liner. The partitioning of the metals in the ashes after combustion or gasification follows conventional behaviour, with most metals retained, and higher concentrations in the finer sizes due to vaporisation and recondensation. The alkali metals have been shown to catalyse the biomass conversion, particularly lithium and potassium, although other metals are active to a lesser extent. The most prevalent in biomass is potassium, which is not only inherently active, but volatilises to become finely distributed throughout the char mass. Because the metals are predominantly found in the ash, the effectiveness of their removal depends on the efficiency of the collection of particulates. The potential for disposal into soil depends on the initial concentration in the feed material.

  13. Heavy metal ions adsorption by suspended particle and sediment of ...

    African Journals Online (AJOL)

    GREGORY

    2012-01-10

    Jan 10, 2012 ... samples in the laboratory, standard metals including Pb, Cu, Zn and Fe (15, 5, 5, and 5 mg/l, respectively) and sediments from the three stations, both arranged in the .... process, lead is separated from gold, silver, zinc and iron but much lead is deposited in waste. Figure 1 shows the situation of the Sorb ...

  14. Effect of ion beam irradiation on metal particle doped polymer ...

    Indian Academy of Sciences (India)

    tural and chemical properties of the composites were studied by means of an LCR meter, X-ray diffraction, FTIR spectroscopy and SEM/AFM, ... This reveals that ion beam irradiation promotes the metal/polymer bonding and converts polymeric ... stirrer at a high speed of around 700 rpm until all polymer grains dissolved.

  15. Heavy metal ions adsorption by suspended particle and sediment of ...

    African Journals Online (AJOL)

    Nowadays, it is important to evaluate the self-purifying capacity of rivers because of the different kinds of pollutants discharged into them. Important kind of pollutants and heavy metals exist in wastewaters industries. When the Sorb Dona mine is placed in Upper Chalus River, in the west of Mazandaran, products of mine ...

  16. Individual metal-bearing particles in a regional haze caused by firecracker and firework emissions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weijun, E-mail: liweijun@sdu.edu.cn [Environment Research Institute, Shandong University, Jinan, Shandong 250100 (China); State Key of Laboratory of Atmospheric Boundary Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 (China); Shi, Zongbo [School of Geography, Earth and Environmental Sciences, University of Birmingham (United Kingdom); Yan, Chao; Yang, Lingxiao; Dong, Can; Wang, Wenxing [Environment Research Institute, Shandong University, Jinan, Shandong 250100 (China)

    2013-01-15

    Intensive firecracker/firework displays during Chinese New Year (CNY) release fine particles and gaseous pollutants into the atmosphere, which may lead to serious air pollution. We monitored ambient PM{sub 2.5} and black carbon (BC) concentrations at a regional background site in the Yellow River Delta region during the CNY in 2011. Our monitoring data and MOUDI images showed that there was a haze event during the CNY. Daily average PM{sub 2.5} concentration reached 183 μg m{sup −3} during the CNY, which was six times higher than that before and after the CNY. Similarly, the black carbon (BC) concentrations were elevated during the CNY. In order to confirm whether the firecracker/firework related emission is the main source of the haze particles, we further analyzed the morphology and chemical composition of individual airborne particles collected before, during and after the CNY by using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (TEM/EDS). We found that sulfate and organic-rich particles were dominant in the atmosphere before and after the CNY. In contrast, K-rich sulfates and other metal (e.g., Ba-rich, Al-rich, Mg-rich, and Fe-rich) particles were much more abundant than ammoniated sulfate particles during the CNY. These data suggest that it was the aerosol particles from the firecracker/firework emissions that induced the regional haze episode during the CNY. In individual organic and K-rich particles, we often found more than two types of nano-metal particles. These metal-bearing particles also contained abundant S but not Cl. In contrast, fresh metal-bearing particles from firecrackers generated in the laboratory contained abundant Cl with minor amounts of S. This indicates that the firecracker/firework emissions during the CNY significantly changed the atmospheric transformation pathway of SO{sub 2} to sulfate. - Highlights: ► TEM was used to observe the aged individual particles from firecrackers

  17. Porous Particles: Controlling Molecular Diffusion within Metal-Organic Frameworks

    Science.gov (United States)

    Jee, Ah-Young; Sindoro, Melinda; Granick, Steve

    2014-03-01

    Systematic investigation of molecular diffusion under nanoconfinement is carried out utilizing pore tunability of ionic metal-organic frameworks (MOFs). The translational and rotational diffusion of specially-selected guest dyes is evaluated by fluorescence correlation microscopy (FCS). A curious novel technique is demonstrated of controlling diffusion by switching counterions. Systematically, this study provides generalizable examples of how pore size, guest size, and host-guest interaction affect diffusion within nanopores.

  18. Characterization of trace metals on soot aerosol particles with the SP-AMS: detection and quantification

    Science.gov (United States)

    Carbone, S.; Onasch, T.; Saarikoski, S.; Timonen, H.; Saarnio, K.; Sueper, D.; Rönkkö, T.; Pirjola, L.; Häyrinen, A.; Worsnop, D.; Hillamo, R.

    2015-11-01

    A method to detect and quantify mass concentrations of trace metals on soot particles by the Aerodyne soot-particle aerosol mass spectrometer (SP-AMS) was developed and evaluated in this study. The generation of monodisperse Regal black (RB) test particles with trace amounts of 13 different metals (Na, Al, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr and Ba) allowed for the determination of the relative ionization efficiency of each metal relative to black carbon (RIEmeas). The observed RIEmeas / RIEtheory values were larger than unity for Na, Rb, Ca, Sr and Ba due to thermal surface ionization (TSI) on the surface of the laser-heated RB particles. Values closer to unity were obtained for the transition metals Zn, Cu, V and Cr. Mn, Fe, and Ni presented the lowest RIEmeas / RIEtheory ratios and highest deviation from unity. The latter discrepancy is unexplained; however it may be related to problems with our calibration method and/or the formation of metal complexes that were not successfully quantified. The response of the metals to the laser power was investigated and the results indicated that a minimum pump laser current of 0.6 A was needed in order to vaporize the metals and the refractory black carbon (rBC). Isotopic patterns of metals were resolved from high-resolution mass spectra, and the mass-weighted size distributions for each individual metal ion were obtained using the high-resolution particle time-of-flight (HR-PToF) method. The RIEmeas values obtained in this study were applied to the data of emission measurements in a heavy-fuel-oil-fired heating station. Emission measurements revealed a large number of trace metals, including evidence for metal oxides and metallic salts, such as vanadium sulfate, calcium sulfate, iron sulfate and barium sulfate, which were identified in the SP-AMS high-resolution mass spectra. SP-AMS measurements of Ba, Fe, and V agreed with ICP-MS analyzed filter samples within a factor of 2 when emitted rBC mass loadings were elevated.

  19. Highly Acidic Ambient Particles, Soluble Metals, and Oxidative Potential: A Link between Sulfate and Aerosol Toxicity.

    Science.gov (United States)

    Fang, Ting; Guo, Hongyu; Zeng, Linghan; Verma, Vishal; Nenes, Athanasios; Weber, Rodney J

    2017-03-07

    Soluble transition metals in particulate matter (PM) can generate reactive oxygen species in vivo by redox cycling, leading to oxidative stress and adverse health effects. Most metals, such as those from roadway traffic, are emitted in an insoluble form, but must be soluble for redox cycling. Here we present the mechanism of metals dissolution by highly acidic sulfate aerosol and the effect on particle oxidative potential (OP) through analysis of size distributions. Size-segregated ambient PM were collected from a road-side and representative urban site in Atlanta, GA. Elemental and organic carbon, ions, total and water-soluble metals, and water-soluble OP were measured. Particle pH was determined with a thermodynamic model using measured ionic species. Sulfate was spatially uniform and found mainly in the fine mode, whereas total metals and mineral dust cations were highest at the road-side site and in the coarse mode, resulting in a fine mode pH metals and OP peaked at the intersection of these modes demonstrating that sulfate plays a key role in producing highly acidic fine aerosols capable of dissolving primary transition metals that contribute to aerosol OP. Sulfate-driven metals dissolution may account for sulfate-health associations reported in past studies.

  20. The effect of metal transfer modes and shielding gas composition on the emission of ultrafine particles in MAG steel welding

    OpenAIRE

    Gomes, J. F.; Miranda, R. M.; Carvalho, P.A.; Quintino, M. L.

    2014-01-01

    The present study aims to characterize ultrafine particles emitted during gas metal arc welding of mild steel and stainless steel, using different shielding gas mixtures, and to evaluate the effect of metal transfer modes, controlled by both processing parameters and shielding gas composition, on the quantity and morphology of the ultrafine particles. It was found that the amount of emitted ultrafine particles (measured by particle number and alveolar deposited surface area) are clearly depen...

  1. Is Metal Particle Release Associated with Peri-implant Bone Destruction? An Emerging Concept.

    Science.gov (United States)

    Fretwurst, T; Nelson, K; Tarnow, D P; Wang, H-L; Giannobile, W V

    2017-11-01

    Peri-implant diseases affecting the surrounding structures of endosseous dental implants include peri-implant mucositis and peri-implantitis. The prevalence of peri-implantitis ranges between 15% and 20% after 10 y, highlighting the major challenge in clinical practice in the rehabilitation of dental implant patients. The widespread nature of peri-implant bone loss poses difficulties in the management of biological complications affecting the long-term success of osseointegrated implant reconstructions. Metal and titanium particles have been detected in peri-implant supporting tissues. However, it remains unclear what mechanisms could be responsible for the elicitation of particle and ion release and whether these released implant-associated materials have a local and/or systemic impact on the peri-implant soft and hard tissues. Metal particle release as a potential etiologic factor has been intensively studied in the field of orthopedics and is known to provoke aseptic loosening around arthroplasties and is associated with implant failures. In dental medicine, emerging information about metal/titanium particle release suggests that the potential impact of biomaterials at the abutment or bone interfaces may have an influence on the pathogenesis of peri-implant bone loss. This mini-review highlights current evidence of metal particle release around dental implants and future areas for research.

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

    Directory of Open Access Journals (Sweden)

    I.A. Kuznetsova

    2014-03-01

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

  3. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

    2016-07-12

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  4. Fabrication of arrayed metallic nano-particles on a flexible substrate for inducing localized surface plasmon resonance.

    Science.gov (United States)

    Chen, Chun-Hung; Lee, Yung-Chun

    2013-02-11

    This paper presents a new method for fabricating periodic arrays of metallic nano-particles on flexible substrates. This method is based on metallic film contact transfer method and high-power pulsed laser annealing. Experiments have been carried out to produce arrayed metallic nano-particles oriented in a hexagonal pattern. The nano-particle size is 70 nm in diameter and the center-to-center pitch of the hexagonal array is 400 nm. Large-area patterning and fabrication of these arrayed nano-particles can be easily achieved up to an area size of few cm(2). Besides, composite or compounded metallic nano-particle arrays can also be produced using different metal materials. The localized surface plasmon resonance (LSPR) effects induced by the fabricated arrays of nano-particles are experimentally observed and quantitatively measured. Numerical simulation on these LPSR effects is performed and the simulation results are in good agreement with experimental data.

  5. Mapping metals incorporation of a whole single catalyst particle using element specific X-ray nanotomography.

    Science.gov (United States)

    Meirer, Florian; Morris, Darius T; Kalirai, Sam; Liu, Yijin; Andrews, Joy C; Weckhuysen, Bert M

    2015-01-14

    Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to combine multiple fields of view, computed tomography was performed to visualize the macropore structure of the catalyst and its availability for mass transport. We mapped the relative spatial distributions of Ni and Fe using multiple-energy tomography at the respective X-ray absorption K-edges and correlated these distributions with porosity and permeability of an equilibrated catalyst (E-cat) particle. Both metals were found to accumulate in outer layers of the particle, effectively decreasing porosity by clogging of pores and eventually restricting access into the FCC particle.

  6. Incorporation of cobalt and nickel metal nano-particles in nano-grain ...

    Indian Academy of Sciences (India)

    Sol-Gel Division, †Glass-Ceramic Coating Division, Central Glass and Ceramic Research Institute, Calcutta 700 032, India. Abstract. Precursor ... films were deposited onto silica glass substrate by the dipping technique. Annealing was ... Nano-grain zirconia; nano particles of cobalt and nickel metals; sol-gel. 1. Introduction.

  7. Capacitive electronic metal-support interactions: Outer surface charging of supported catalyst particles

    Science.gov (United States)

    Binninger, Tobias; Schmidt, Thomas J.; Kramer, Denis

    2017-10-01

    Electronic metal-support interactions (EMSI) in catalysis are commonly rationalized in terms of an electron transfer between support material and supported metal catalyst particles. This general perspective, however, cannot fully explain experimentally observed EMSI for metallic nanoparticulate catalysts, because the strong charge screening of metals should locally confine effects of direct electronic interaction with the support to the catalyst-support interface (CSI), which, apart from the perimeter, is largely inaccessible for catalysis reactants. The concept of capacitive EMSI is proposed here for catalyst particles at the nanometer scale, where electronic equilibration results in a long-range charging of the catalytically active outer surface (CAOS) bypassing the expected strong metallic charge screening, which is confirmed and quantified by electrostatic and density functional theory simulations revealing a strong dependence on the coverage of the support surface with catalyst particles. This long-range charge transfer leads to a shift of the local work function at the CAOS. In order to describe the catalytic consequences, an amendment of d -band theory in terms of `d -band + work function' is proposed. Furthermore, the charging of remote catalytic sites at the CAOS scales with the relative dielectric constant of the surrounding medium, and it is concluded that EMSI can have surprisingly strong influence especially in the presence of a strongly polarizable dielectric.

  8. Complexation- and ligand-induced metal release from 316L particles: importance of particle size and crystallographic structure.

    Science.gov (United States)

    Hedberg, Yolanda; Hedberg, Jonas; Liu, Yi; Wallinder, Inger Odnevall

    2011-12-01

    Iron, chromium, nickel, and manganese released from gas-atomized AISI 316L stainless steel powders (sized 316L particles immersed in ALF. Iron was mainly released, while manganese was preferentially released as a consequence of the reduction of manganese oxide on the surface. These processes resulted in highly complexing media in a partial oxidation of trivalent chromium to hexavalent chromium on the surface. The extent of metal release was partially controlled by surface properties (e.g., availability of elements on the surface and structure of the outermost surface) and partially by the complexation capacity of the different metals with the complexing agents of the different media. In general, compared to the coarse powder (<45 μm), the fine (<4 μm) powder displayed significantly higher released amounts of metals per surface area, increased with increased solution complexation capacity, while less amounts of metals were released into non-complexing solutions. Due to the ferritic structure of lower solubility for nickel of the fine powder, more nickel was released into all solutions compared with the coarser powder.

  9. Behavior of ceramic particles at the solid-liquid metal interface in metal matrix composites

    Science.gov (United States)

    Stefanescu, D. M.; Dhindaw, B. K.; Kacar, S. A.; Moitra, A.

    1988-01-01

    Directional solidification results were obtained in order to investigate particle behavior at the solid-liquid interface in Al-2 pct Mg (cellular interface) and Al-6.1 pct Ni (eutectic interface) alloys. It is found that particles can be entrapped in the solid if adequate solidification rates and temperature gradients are used. Model results showed critical velocity values slightly higher than those obtained experimentally.

  10. Particle size and metals concentrations of dust from a paint manufacturing plant.

    Science.gov (United States)

    Huang, Siew Lai; Yin, Chun-Yang; Yap, Siaw Yang

    2010-02-15

    In this study, the particle size distribution and concentration of metallic elements of solvent- and water-based paint dust from bulk dust collected from dust-collecting hoppers were determined. The mean particle size diameter over a 12-week sampling period was determined using a particle size analyzer. The metals composition and concentration of the dust were determined via acid digestion technique followed by concentration analysis using inductively coupled plasma. The volume weighted mean particle diameters were found to be 0.941+/-0.016 and 8.185+/-0.201 microm for solvent- and water-based paint dust, respectively. The mean concentrations of metals in solvent-based paint dust were found to be 100+/-20.00 microg/g (arsenic), 1550+/-550.00 microg/g (copper), 15,680+/-11,780.00 microg/g (lead) and 30,460+/-10,580.00 microg/g (zinc) while the mean concentrations of metals in water-based paint dust were found to be 20.65+/-6.11 microg/g (arsenic), 9.14+/-14.65 microg/g (copper), 57.46+/-22.42 microg/g (lead) and 1660+/-1260 microg/g (zinc). Both paint dust types could be considered as hazardous since almost all of the dust particles were smaller than 10 microm. Particular emphasis on containment of solvent-based paint dust particles should be given since it was shown that they were very fine in size (<1 microm) and had high lead and zinc concentrations.

  11. Adsorption of Heavy Metals in Industrial Wastewater by Magnetic Nano-particles

    Science.gov (United States)

    Tu, Y.; You, C.

    2010-12-01

    Industrial wastewater containing heavy metals is of great concern because of their toxic impact to living species and environments. Removal of metal ions from industrial effluent using nano-particles is an area of extensive research. This study collected wastewaters and effluents from 11 industrial companies in tanning, electronic plating, printed circuit board manufacturing, semi-conductor, and metal surface treatment industry and studied in detailed the major and trace element compositions to develop potential fingerprinting technique for pollutant source identification. The results showed that electronic plating and metal surface treatment industry produce high Fe, Mn, Cr, Zn, Ni and Mo wastewater. The tanning industry and the printed circuit board manufacturing industry released wastewater with high Fe and Cr, Cu and Ni, respectively. For semi-conductor industry, significant dissolved In was detected in wastewater. The absorption experiments to remove heavy metals in waters were conducted using Fe3O4 nano-particles. Under optimal conditions, more than 99 % dissolved metals were removed in a few minutes.

  12. Towards High Capacity Li-ion Batteries Based on Silicon-Graphene Composite Anodes and Sub-micron V-doped LiFePO4 Cathodes

    Science.gov (United States)

    Loveridge, M. J.; Lain, M. J.; Johnson, I. D.; Roberts, A.; Beattie, S. D.; Dashwood, R.; Darr, J. A.; Bhagat, R.

    2016-11-01

    Lithium iron phosphate, LiFePO4 (LFP) has demonstrated promising performance as a cathode material in lithium ion batteries (LIBs), by overcoming the rate performance issues from limited electronic conductivity. Nano-sized vanadium-doped LFP (V-LFP) was synthesized using a continuous hydrothermal process using supercritical water as a reagent. The atomic % of dopant determined the particle shape. 5 at. % gave mixed plate and rod-like morphology, showing optimal electrochemical performance and good rate properties vs. Li. Specific capacities of >160 mAh g-1 were achieved. In order to increase the capacity of a full cell, V-LFP was cycled against an inexpensive micron-sized metallurgical grade Si-containing anode. This electrode was capable of reversible capacities of approximately 2000 mAh g-1 for over 150 cycles vs. Li, with improved performance resulting from the incorporation of few layer graphene (FLG) to enhance conductivity, tensile behaviour and thus, the composite stability. The cathode material synthesis and electrode formulation are scalable, inexpensive and are suitable for the fabrication of larger format cells suited to grid and transport applications.

  13. Facile synthesis and characterization of novel rapid-setting spherical sub-micron bioactive glasses cements and their biocompatibility in vitro.

    Science.gov (United States)

    Li, Yuli; Liang, Qiming; Lin, Cai; Li, Xian; Chen, Xiaofeng; Hu, Qing

    2017-06-01

    Dental pulp vitality is extremely important for the tooth viability, since it provides nutrition and forms the dentin. Bioactive glasses (BGs) may be promising materials for pulp repair due to their excellent abilities of rapidly bonding to bone and stimulating new bone growth. However, the unsatisfied handling property, low plasticity, and poor rapid-setting property of traditional BGs limit its application in vital pulp therapy. Spherical bioactive glasses (SBGs) exhibited higher osteogenesis and odontogenic differentiation than irregular BGs. This study focuses on the application of SBGs with rapid setting property for dental pulp repair. Here, SBGs with various compositions were successfully synthesized by a sol-gel process using dodecylamine (DDA) served as both a catalyst and a template. The maximum content of CaO in SBGs was about 15%. The non-bridge oxygen amounts of the SiO network and the apatite-forming ability increased with the content proportion of CaO and P2O5. Bioactive glass pulp capping materials (BGPCMs) were prepared by mixing the SBGs powders and the phosphate buffer solution (PBS). The K3CaH(PO4)2 and hydroxyapatite (HA) formed between SBGs particles as soon as they were mixed with PBS solution. The compressive strengths of fully set BCPCM-2 molded were measured to be 31.76±1.9577MPa after setting for 24h. The K3CaH(PO4)2 and the low crystallinity HA phases at the initial stage of solidification transformed to crystalline HA for 3days, and the compressive strength was still higher than 10MPa. Additionally, SBG-2 with a designed molar composition of 35% SiO2, 55% CaO and 10% P2O5 more promoted dental pulp cell proliferation, and could be potential pulp capping applications. Copyright © 2017. Published by Elsevier B.V.

  14. Earthworm bioturbation influences the phytoavailability of metals released by particles in cultivated soils.

    Science.gov (United States)

    Leveque, Thibaut; Capowiez, Yvan; Schreck, Eva; Xiong, Tiantian; Foucault, Yann; Dumat, Camille

    2014-08-01

    The influence of earthworm activity on soil-to-plant metal transfer was studied by carrying out six weeks mesocosms experiments with or without lettuce and/or earthworms in soil with a gradient of metal concentrations due to particles fallouts. Soil characteristics, metal concentrations in lettuce and earthworms were measured and soil porosity in the mesocosms was determined. Earthworms increased the soil pH, macroporosity and soil organic matter content due to the burying of wheat straw provided as food. Earthworm activities increased the metals concentrations in lettuce leaves. Pb and Cd concentrations in lettuce leaves can increase up to 46% with earthworm activities … These results and the low correlation between estimated by CaCl2 and EDTA and measured pollutant phytoavailability suggest that earthworm bioturbation was the main cause of the increase. Bioturbation could affect the proximity of pollutants to the roots and soil organic matter. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Digital image processing of nanometer-size metal particles on amorphous substrates

    Science.gov (United States)

    Soria, F.; Artal, P.; Bescos, J.; Heinemann, K.

    1989-01-01

    The task of differentiating very small metal aggregates supported on amorphous films from the phase contrast image features inherently stemming from the support is extremely difficult in the nanometer particle size range. Digital image processing was employed to overcome some of the ambiguities in evaluating such micrographs. It was demonstrated that such processing allowed positive particle detection and a limited degree of statistical size analysis even for micrographs where by bare eye examination the distribution between particles and erroneous substrate features would seem highly ambiguous. The smallest size class detected for Pd/C samples peaks at 0.8 nm. This size class was found in various samples prepared under different evaporation conditions and it is concluded that these particles consist of 'a magic number' of 13 atoms and have cubooctahedral or icosahedral crystal structure.

  16. Image processing enhancement of high-resolution TEM micrographs of nanometer-size metal particles

    Science.gov (United States)

    Artal, P.; Avalos-Borja, M.; Soria, F.; Poppa, H.; Heinemann, K.

    1989-01-01

    The high-resolution TEM detectability of lattice fringes from metal particles supported on substrates is impeded by the substrate itself. Single value decomposition (SVD) and Fourier filtering (FFT) methods were applied to standard high resolution micrographs to enhance lattice resolution from particles as well as from crystalline substrates. SVD produced good results for one direction of fringes, and it can be implemented as a real-time process. Fourier methods are independent of azimuthal directions and allow separation of particle lattice planes from those pertaining to the substrate, which makes it feasible to detect possible substrate distortions produced by the supported particle. This method, on the other hand, is more elaborate, requires more computer time than SVD and is, therefore, less likely to be used in real-time image processing applications.

  17. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    Energy Technology Data Exchange (ETDEWEB)

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  18. Synthesis of scintillating metal organic frameworks for the detection of radiation from subatomic particles

    Science.gov (United States)

    Ingram, Conrad; Williams, Michael

    2013-04-01

    The objective of this research is to develop fluorescent metal organic frameworks (MOFs) as scintillation materials for more efficient light output and detection of ionizing radiation, such as neutrons, alpha particles or gamma rays, generated by fissile materials. MOFs are multidimensional porous structures, which are synthesized from the covalent bonding of metal ions or metal oxide clusters with organic ligand linkers, such as benzene dicarboxylates. The ligands will be chosen to have fluorescent characteristics, when excited by radiation or energetic sub-atomic particles. We will explore the synthesis of new MOFs, containing carboxylate ligands with unique conjugated chromophores, such as, benzene-1,3,5-triyltris(ethene-2,1-diyl)) tribenzoic acid and 9-hydroxy-9-vinyl-9H-fluorene-2,7-dicarboxylic acid), and doped with heavy metal as triplet-state harvesters, that we are proposing will result in stronger and possibly, unique luminescence spectral features that will allow for the discrimination between different ionizing radiations from subatomic particles. Photo-, catho- and radio-luminescence studies will be conducted on the materials, and radiation mechanism(s) will be investigated.

  19. In vitro genotoxic effects of different combinations of cobalt and metallic carbide particles.

    Science.gov (United States)

    De Boeck, Marlies; Lombaert, Noömi; De Backer, Sofie; Finsy, Robert; Lison, Dominique; Kirsch-Volders, Micheline

    2003-03-01

    Occupational exposure to hard metal dust, consisting of tungsten carbide (WC) and metallic cobalt particles (Co), is associated with an increased risk of lung cancer, while no increased risk was observed in workers exposed to Co alone. In vitro, in human peripheral blood mononucleated cells (PBMC), we previously demonstrated that WC-Co is more genotoxic than Co and WC alone. A possible mechanism underlying this higher genotoxicity is a specific physicochemical interaction between Co and WC particles leading to the enhanced short-term formation of active oxygen species. The aim of this study was to evaluate the in vitro genotoxicity of other combinations of Co with metal carbide particles in comparison with WC-Co. The ability of Cr(3)C(2), Mo(2)C and NbC and of their powder mixtures with Co to induce DNA strand breaks and alkali-labile sites was assessed by the alkaline Comet assay and their potential to induce chromosome(/genome) mutations by the cytokinesis-block micronucleus test on human PBMC from two donors. PBMC were treated in vitro for 15 min, 24 h after the onset of PHA stimulation. In the micronucleus test, while the metal carbides alone did not increase the micronucleus frequency, Co alone and the four tested carbide-Co mixtures induced a statistically significant concentration-dependent increase in micronucleated binucleates. In addition to WC, NbC and Cr(3)C(2) particles were able to interact with Co, producing a higher mutagenic effect than the individual metal particles. Mo(2)C particles did not display interactive mutagenicity with Co in the micronucleus test, possibly related to their small specific surface area, compactness and/or spherical shape. With the Comet assay, applied directly at the end of the treatment, less clear results, due to inter-experimental and inter-donor variation, were obtained. These data indicate that particular interaction of a metal carbide with Co leading to enhanced mutagenicity is not specific for WC.

  20. Platinum group metal particles aggregation in nuclear glass melts under the effect of temperature

    Science.gov (United States)

    Hanotin, Caroline; Puig, Jean; Neyret, Muriel; Marchal, Philippe

    2016-08-01

    The viscosity of simulated high level radioactive waste glasses containing platinum group metal particles is studied over a wide range of shear stress, as a function of the particles content and the temperature, thanks to a stress imposed rheometer, coupled to a high-temperature furnace. The system shows a very shear thinning behavior. At high shear rate, the system behaves as a suspension of small clusters and individual particles and is entirely controlled by the viscosity of the glass matrix as classical suspensions. At low shear rate, above a certain fraction in platinum group metal particles, the apparition of macroscopic aggregates made up of chains of RuO2 particles separated by thin layers of glass matrix strongly influences the viscosity of the nuclear glass and leads, in particular, to the apparition of yield stress and thixotropic effects. The maximum size of these clusters as well as their effective volume fraction have been estimated by a balance between Van der Waals attractive forces and hydrodynamic forces due to shear flow. We showed experimentally and theoretically that this aggregation phenomenon is favored by an increase of the temperature, owing to the viscosity decrease of the glass matrix, leading to an unusual increase of the suspension viscosity.

  1. An Analysis of the Retention of a Diamond Particle in a Metallic Matrix after Hot Pressing

    Directory of Open Access Journals (Sweden)

    Borowiecka-Jamrozek J.

    2017-03-01

    Full Text Available This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the radius of plastic zone around particle.

  2. Growth dynamics of carbon-metal particles and nanotubes synthesized by CO2 laser vaporization

    Science.gov (United States)

    Kokai, F.; Takahashi, K.; Yudasaka, M.; Iijima, S.

    To study the growth of carbon-Co/Ni particles and single-wall carbon nanotubes (SWNTs) by 20 ms CO2 laser-pulse irradiation of a graphite-Co/Ni (1.2 at.%) target in an Ar gas atmosphere (600 Torr), we used emission imaging spectroscopy and shadowgraphy with a temporal resolution of 1.67 ms. Wavelength-selected emission images showed that C2 emission was strong in the region close to the target (within 2 cm), while for the same region the blackbody radiation from the large clusters or particles increased with increasing distance from the target. Shadowgraph images showed that the viscous flow of carbon and metal species formed a mushroom or a turbulent cloud spreading slowly into the Ar atmosphere, indicating that particles and SWNTs continued to grow as the ejected material cooled. In addition, emission imaging spectroscopy at 1200 °C showed that C2 and hot clusters and particles with higher emission intensities were distributed over much wider areas. We discuss the growth dynamics of the particles and SWNTs through the interaction of the ambient Ar with the carbon and metal species released from the target by the laser pulse.

  3. Distribution, bioavailability, and leachability of heavy metals in soil particle size fractions of urban soils (northeastern China).

    Science.gov (United States)

    Yutong, Zong; Qing, Xiao; Shenggao, Lu

    2016-07-01

    This study examines the distribution, mobility, and potential environmental risks of heavy metals in various particle size fractions of urban soils. Representative urban topsoils (ten) collected from Anshan, Liaoning (northeastern China), were separated into six particle size fractions and their heavy metal contents (Cr, Cu, Cd, Pb, and Zn) were determined. The bioaccessibility and leachability of heavy metals in particle size fractions were evaluated using the toxicity characteristic leaching procedure (TCLP) and ethylenediaminetetraacetic acid (EDTA) extraction, respectively. The results indicated that the contents of five heavy metals (Cd, Cr, Cu, Pb and Zn) in the size fractions increased with the decrease of particle size. The clay fraction of size fractions in urban topsoils. Cr also concentrated in the coarse fraction of 2000-1000 μm, indicating a lithogenic contribution. However, the dominant size fraction responsible for heavy metal accumulation appeared to belong to particle fraction of 50-2 μm. The lowest distribution factors (DFs) of heavy metals were recorded in the 2000- to 1000-μm size fraction, while the highest in the clay fraction. The DFs of heavy metals in the clay fraction followed Zn (3.22) > Cu (2.84) > Pb (2.61) > Cr (2.19) > Cd (2.05). The enrichment factor suggested that the enrichment degree of heavy metal increased with the decrease of the particle size, especially for Cd and Zn. The TCLP- and EDTA-extractable concentrations of heavy metals in the clay fraction were relatively higher than those in coarse particles. Cd bioavailability was higher in the clay fraction than in other fractions or whole soils. In contrast, Cr exhibits similar bioaccessibilities in the six size fractions of soils. The results suggested that fine particles were the main sources of potentially toxic metals in urban soils. The variation of heavy metals in various size fractions should be taken into account in environment assessments.

  4. Characterization of airborne particles generated from metal active gas welding process.

    Science.gov (United States)

    Guerreiro, C; Gomes, J F; Carvalho, P; Santos, T J G; Miranda, R M; Albuquerque, P

    2014-05-01

    This study is focused on the characterization of particles emitted in the metal active gas welding of carbon steel using mixture of Ar + CO2, and intends to analyze which are the main process parameters that influence the emission itself. It was found that the amount of emitted particles (measured by particle number and alveolar deposited surface area) are clearly dependent on the distance to the welding front and also on the main welding parameters, namely the current intensity and heat input in the welding process. The emission of airborne fine particles seems to increase with the current intensity as fume-formation rate does. When comparing the tested gas mixtures, higher emissions are observed for more oxidant mixtures, that is, mixtures with higher CO2 content, which result in higher arc stability. These mixtures originate higher concentrations of fine particles (as measured by number of particles by cm(3) of air) and higher values of alveolar deposited surface area of particles, thus resulting in a more severe worker's exposure.

  5. Hydrodynamic interactions in metal rod-like particle suspensions due to induced charge electroosmosis

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K A; Hoffman, B; Saintillan, D; Shaqfeh, E G; Santiago, J G

    2008-05-05

    We present a theoretical and experimental study of the role of hydrodynamic interactions on the motion and dispersion of metal rod-like particles in the presence of an externally applied electric field. In these systems, the electric field polarizes the particles and induces an electroosmosis flow relative to the surface of each particle. The simulations include the effect of the gravitational body force, buoyancy, far-field hydrodynamic interactions, near-field lubrication forces, and electric field interactions. The particles in the simulations and experiments were observed to experience repeated pairing interactions in which they come together axially with their ends approaching each other, slide past one another until their centers approach, and then push apart. These interactions were confirmed in measurements of particle orientations and velocities, pair distribution functions, and net dispersion of the suspension. For large electric fields, the pair distribution functions show accumulation and depletion regions consistent with many pairing events. For particle concentrations of 1e8 particles/mL and higher, dispersion within the suspension dramatically increases with increased field strength.

  6. In-flight behavior of dissimilar co-injected particles in the spraying of metal-ceramic functionally gradient materials

    Energy Technology Data Exchange (ETDEWEB)

    Fincke, J.R.; Swank, W.D.; Haggard, D.C. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-12-31

    In the spraying of functionally gradient coatings the particle ensemble delivered to the substrate can vary from a relatively low melting point metallic particle to a significantly higher melting point ceramic particle. At various stages in the spray process the particle ensemble can be either predominantly metallic, ceramic, or an intermediate combination. For co-injected particles the mixtures do not behave as a simple linear superposition of the spray patterns of the individual particle types. The particle temperature, velocity, size distributions, and pattern characteristics of the resulting spray fields is examined for all ceramic particle sprays (ZrO{sub 2}), all metallic particle sprays (NiCrAlY), and for a 1:1 mixture. The major particle-particle interaction occurs in the injector itself and results in a modified spray pattern which is different from that of either material sprayed alone. The particle velocity distributions generally exhibit a bimodal nature which is dependent on the size and density of the injected particles.

  7. Absorbed dose assessment in particle-beam irradiated metal-oxide and metal-nonmetal memristors

    Directory of Open Access Journals (Sweden)

    Knežević Ivan D.

    2012-01-01

    Full Text Available Absorbed dose was estimated after Monte Carlo simulation of proton and ion beam irradiation on metal-oxide and metal-nonmetal memristors. A memristive device comprises two electrodes, each of a nanoscale width, and a double-layer active region disposed between and in electrical contact with electrodes. Following materials were considered for the active region: titanium dioxide, zirconium dioxide, hafnium dioxide, strontium titanium trioxide and galium nitride. Obtained results show that significant amount of oxygen ion - oxygen and nonmetal ion - nonmetal vacancy pairs is to be generated. The loss of such vacancies from the device is believed to deteriorate the device performance over time. Estimated absorbed dose values in the memristor for different constituting materials are of the same order of magnitude because of the close values of treshold displacement energies for the investigated materials.

  8. Characterization of trace metals in airborne carbonaceous aerosols by single-particle EDX – Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Pietrodangelo A.

    2013-04-01

    Full Text Available The presence of fine and ultrafine metal particles has been evidenced in size segregated airborne carbonaceous aerosols collected at one industrial and two background (urban and rural sites during an extended field campaign in Central Italy. Analysis of the backscattered electrons (BSE by SEM – EDX demonstrated an effective potential in evidencing main structural features of the metal content in identified carbon aerosols. Many observed ultrafine metal particles appear embedded in the skeleton of carbonaceous individual particles and aggregates in the coarse fraction, while the same is not evident in the case of mixed carbon-sulphates aerosol that has been detected in the submicron size. These carbon-sulphates formations include indeed nano-sized metal particles that appear physically combined but not embedded. Also, larger metal particles (ranging around 1 μm physical size were observed close to carbon materials, but not included in their structure. Main compositional differences of metal particles with size segregation could be evidenced by energy – dispersive X ray spectrometry (EDX. Larger particles are mainly rich in Fe, frequently in presence of Mn, Cu, Cr and Zn in variable proportions; either oxidized or elemental metals were detected. On the other hand, ultrafine particles associated with carbon–sulphates aerosol are enriched in Pb and Zn, although the presence of other trace elements not detectable by SEM – EDX technique cannot be excluded. Moreover, Ce-enriched ultrafine particles were clearly determined in cenospheres. Conversely, inclusion of fine and ultrafine metal particles was rarely or not observed in soot aggregates.

  9. Detection of charge dynamics of a tetraphenylporphyrin particle using GaAs-based nanowire enhanced by particle-metal tip capacitive coupling

    Science.gov (United States)

    Okamoto, Shoma; Sato, Masaki; Sasaki, Kentaro; Kasai, Seiya

    2017-06-01

    We investigate a detection technique of charge dynamics of a molecular particle using a GaAs-based nanowire where the charge sensitivity is locally enhanced by particle-metal tip capacitive coupling. By equivalent circuit analysis, it was clarified that the nanowire channel potential becomes sensitive to the molecular particle on the nanowire when the particle is capacitively coupled with a metal tip. The concept was demonstrated using a GaAs-based nanowire with tetraphenylporphyrin (TPP) particles on its surface and a measurement system integrating an atomic force microscope (AFM) and a dynamic current measurement monitor/spectrum analyzer. When the metal tip was in contact with a TPP particle on the nanowire under an appropriate tip bias condition, random telegraph signal (RTS) noise was imposed on the nanowire current, suggesting the increase in sensitivity to the charge state of the particle by the metal tip contact. We discussed the origin of the RTS noise through analysis of the time constant of RTS noise, RTS amplitude, and noise spectrum.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  11. Effect of particle size on thermal decomposition of alkali metal picrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Zhang, Tonglai, E-mail: ztlbit@bit.edu.cn; Yang, Li; Zhou, Zunning

    2014-05-01

    Graphical abstract: The smaller-sized picrate has greater gas emission than do its larger counterpart. The small size effect reduces the thermal decomposition activation energy, accelerates the reaction rate, and promotes the reaction activity. - Highlights: • Picrates were prepared into three micron sizes by microemulsion synthesis. • Thermal decomposition kinetics and thermodynamics were studied by DPTA and DSC. • Smaller-sized picrate has higher activity and faster reaction rate. • Particle size effect on thermal decomposition kinetics and thermodynamics was revealed. - Abstract: Three alkali metal picrates, KPA, RbPA and CsPA, were prepared into three micron sizes by microemulsion synthesis, and their thermal decomposition behaviors were investigated by DPTA at different temperatures and by DSC at different heating rates. The smaller-sized picrate has greater gas emission and smaller kinetic and thermodynamic parameters than do its larger counterpart. It can be attributed to the decreasing particle size which leads to the high surface energy, the fast mass and heat transfer, and the increasing active sites on the reaction interface. The small size effect and surface effect cause the autocatalysis which reduces the activation energy and promotes the reaction activity. The particle size does not affect the reaction mechanism. However, the picrates with different central alkali metals exhibit different reaction mechanisms even though they are of the same size. This is because the central metal determines the bond energy and consequently affects the stability of picrate.

  12. Geochemical phase and particle size relationships of metals in urban road dust.

    Science.gov (United States)

    Jayarathne, Ayomi; Egodawatta, Prasanna; Ayoko, Godwin A; Goonetilleke, Ashantha

    2017-11-01

    Detailed knowledge of the processes that metals undergo during dry weather periods whilst deposited on urban surfaces and their environmental significance is essential to predict the potential influence of metals on stormwater quality in order to develop appropriate stormwater pollution mitigation measures. However, very limited research has been undertaken in this area. Accordingly, this study investigated the geochemical phase and particle size relationships of seven metals which are commonly associated with urban road dust, using sequential extraction in order to assess their mobility characteristics. Metals in the sequentially extracted fractions of exchangeable, reducible, oxidisable and residual were found to follow a similar trend for different land uses even though they had variable accumulation loads. The high affinity of Cd and Zn for exchangeable reactions in both, bulk and size-fractionated solid samples confirmed their high mobility, while the significant enrichment of Ni and Cr in the stable residual fraction indicated a low risk of mobility. The study results also confirmed the availability of Cu, Pb and Mn in both, stable and mobile fractions. The fine fraction of solids (<150 μm) and antecedent dry days can be highlighted as important parameters when determining the fate of metals associated with urban road dust. The outcomes from this study are expected to contribute to the development of effective stormwater pollution mitigation strategies by taking into consideration the metal-particulate relationships. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Simulation and quantitative assessment of homogeneous and inhomogeneous particle distributions in particulate metal matrix composites.

    Science.gov (United States)

    Yang, N.; Boselli, J.; Sinclair, I.

    2001-02-01

    Reinforcement distributions play an important role in various aspects of the processing and final mechanical behaviour of particulate metal matrix composites (PMMCs). Methods for quantifying spatial distribution in such materials are, however, poorly developed, particularly in relation to the range of particle size, shape and orientation that may be present in any one system. The present work investigates via computer simulations the influences of particle morphology, homogeneity and inhomogeneity on spatial distribution measurements obtained by finite-body tessellation. Distribution inhomogeneity was simulated both by the segregation of particles away from specified regions within a microstructure and by generating point density peaks at random locations within a microstructure. Both isotropic and anisotropic inhomogeneous distributions were considered to simulate distribution patterns in PMMCs before and after mechanical working. It was found that the coefficient of variation of the mean near-neighbour distance (COV(dmean)), derived from particle interfaces using finite-body tessellation, was essentially independent of particle shape, size distribution, orientation and area fraction in homogeneous (random) distributions, but showed great sensitivity to inhomogeneity. Increased values of COV(dmean) were seen for both forms of inhomogeneous distributions considered here, with little influence of particle morphology. The COV(dmean) was also seen to be sensitive to anisotropic clustering, the presence of which was identified via nearest-neighbour angles and cell orientations. Although generally formulated for PMMCs, the present results may be generalized to other systems containing low aspect ratio finite bodies of low to moderate area fraction.

  14. Assessing the antifouling properties of cold-spray metal embedment using loading density gradients of metal particles.

    Science.gov (United States)

    Vucko, M J; King, P C; Poole, A J; Hu, Y; Jahedi, M Z; de Nys, R

    2014-01-01

    Particles of copper, bronze and zinc were embedded into a polymer using cold-spray technology to produce loading density gradients of metal particles. The gradients were used to identify the species with the highest tolerance to the release of copper and zinc ions. The gradients also established the minimum effective release rates (MERRs) of copper and zinc ions needed to prevent the recruitment of fouling under field conditions. Watersipora sp. and Simplaria pseudomilitaris had the highest tolerances to the release of metal ions. Copper and bronze gradient tubes were similar in their MERRs of copper ions against Watersipora sp. (0.058 g m(-2) h(-1) and 0.054 g m(-2) h(-1), respectively) and against S. pseudomilitaris (0.030 g m(-2) h(-1) and 0.025 g m(-2) h(-1), respectively). Zinc was not an effective antifoulant, with failure within two weeks. In conclusion, cold-spray gradients were effective in determining MERRs and these outcomes provide the basis for the development of cold-spray surfaces with pre-determined life-spans using controlled MERRs.

  15. Interaction of Heavy Metal Ions with Carbon and Iron Based Particles

    Directory of Open Access Journals (Sweden)

    Dana Fialova

    2014-03-01

    Full Text Available Due to the rapid development of industry and associated production of toxic waste, especially heavy metals, there is a great interest in creating and upgrading new sorption materials to remove these pollutants from the environment. This study aims to determine the effectiveness of different carbon forms (graphene, expanded carbon, multi-wall nanotubes and paramagnetic particles (Fe2O3 for adsorption of cadmium(II, lead(II, and copper(II on its surface, with different interaction time from 1 min to 24 h. The main attention is paid to the detection of these metals using differential pulse voltammetry. Based on the obtained results, graphene and Fe2O3 are found to be good candidates for removal of heavy metals from the environment.

  16. Metallic particles into mechanical and hydraulic systems in agricultural and construction machines

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jair Rosas da; Silva, Deise Paula da [Instituto Agronomico de Campinas (IAC), Campinas, SP (Brazil). Centro de Engenharia Agricola; Bormio, Marcos Roberto [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Fac. de Engenharia

    2008-07-01

    The lubricant oil analysis are an indicator of the conditions how the lubricant is, may to allow the prevision of damages that occurred into machine due to the internal abrasion of hydraulic and mechanical components of the machines. The present study had the objective to determine the kind and quantity of the metallic particles that occurred into the lubricant oil of the mechanical and hydraulic compartments of the energy transmission systems of three kinds of machines: a tracked-tractor, a sugarcane harvester and a group of power-shovels. The metallic particles presents into these compartments were determined under laboratory tests and concerning to the following elements: iron, copper, chromium, lead, nickel, aluminum, silex, tin and molybdenum. About to the tracked-tractor, the metallic contaminators into to the oil charges surpasses the tolerate levels, considering the technical standards adopted in this evaluation. In the sugarcane harvester only a metallic element in excess was identified and, in a power-shovel group it was showed the need to correct air false entrances in the hydraulic or mechanical systems due the high presence of silex element. (author)

  17. Cardiopulmonary responses of intratracheally instilled tire particles and constituent metal components

    Science.gov (United States)

    Gottipolu, R.R.; Landa, E.R.; Schladweiler, M.C.; McGee, J.K.; Ledbetter, A.D.; Richards, J.H.; Wallenborn, G.J.; Kodavanti, U.P.

    2008-01-01

    Tire and brake wear particles contain transition metals, and contribute to near-road PM. We hypothesized that acute cardiopulmonary injury from respirable tire particles (TP) will depend on the amount of soluble metals. Respirable fractions of two types of TP (TP1 and TP2) were analyzed for water and acid-leachable metals using ICP-AES. Both TP types contained a variety of transition metals, including zinc (Zn), copper (Cu), aluminum, and iron. Zn and Cu were detected at high levels in water-soluble fractions (TP2 > TP1). Male Wistar Kyoto rats (12-14 wk) were intratracheally instilled, in the first study, with saline, TP1 or TP2 (5 mg/kg), and in the second study, with soluble Zn, Cu (0.5 ??mol/kg), or both. Pulmonary toxicity and cardiac mitochondrial enzymes were analyzed 1 d, 1 wk, or 4 wk later for TP and 4 or 24 h later for metals. Increases in lavage fluid markers of inflammation and injury were observed at d 1 (TP2 > TP1), but these changes reversed by wk 1. No effects on cardiac enzymes were noted with either TP. Exposure of rats to soluble Zn and Cu caused marked pulmonary inflammation and injury but temporal differences were apparent (Cu effects peaked at 4 h and Zn at 24 h). Instillation of Zn, Cu, and Zn+ Cu decreased the activity of cardiac aconitase, isocitrate dehydrogenase, succinate dehydrogenase, cytochrome-c-oxidase and superoxide dismutase suggesting mitochondrial oxidative stress. The observed acute pulmonary toxicity of TP could be due to the presence of water soluble Zn and Cu. At high concentrations these metals may induce cardiac oxidative stress. Copyright ?? Informa Healthcare USA, Inc.

  18. Chemodynamics of metal ion complexation by charged nanoparticles: a dimensionless rationale for soft, core-shell and hard particle types.

    Science.gov (United States)

    Duval, Jérôme F L

    2017-05-17

    Soft nanoparticulate complexants are defined by a spatial confinement of reactive sites and electric charges inside their 3D body. In turn, their reactivity with metal ions differs significantly from that of simple molecular ligands. A revisited form of the Eigen mechanism recently elucidated the processes leading to metal/soft particle pair formation. Depending on e.g. particle size and metal ion nature, chemodynamics of nanoparticulate metal complexes is controlled by metal conductive diffusion to/from the particles, by intraparticulate complex formation/dissociation kinetics, or by both. In this study, a formalism is elaborated to achieve a comprehensive and systematic identification of the rate-limiting step governing the overall formation and dissociation of nanoparticulate metal complexes. The theory covers the different types of spherical particulate complexants, i.e. 3D soft/permeable and core-shell particles, and hard particles with reactive sites at the surface. The nature of the rate-limiting step is formulated by a dynamical criterion involving a power law function of the ratio between particle radius and an intraparticulate reaction layer thickness defined by the key electrostatic, diffusional and kinetic components of metal complex formation/dissociation. The analysis clarifies the intertwined contributions of particle properties (size, soft or hard type, charge, density or number of reactive sites) and aqueous metal ion dehydration kinetics in defining the chemodynamic behavior of nanoparticulate metal complexes. For that purpose, fully parameterized chemodynamic portraits involving the defining features of particulate ligand and metal ion as well as the physicochemical conditions in the local intraparticulate environment, are constructed and thoroughly discussed under conditions of practical interest.

  19. Thermoelectric properties of semiconductor-metal composites produced by particle blending

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2016-10-01

    Full Text Available In the quest for more efficient thermoelectric material able to convert thermal to electrical energy and vice versa, composites that combine a semiconductor host having a large Seebeck coefficient with metal nanodomains that provide phonon scattering and free charge carriers are particularly appealing. Here, we present our experimental results on the thermal and electrical transport properties of PbS-metal composites produced by a versatile particle blending procedure, and where the metal work function allows injecting electrons to the intrinsic PbS host. We compare the thermoelectric performance of composites with microcrystalline or nanocrystalline structures. The electrical conductivity of the microcrystalline host can be increased several orders of magnitude with the metal inclusion, while relatively high Seebeck coefficient can be simultaneously conserved. On the other hand, in nanostructured materials, the host crystallites are not able to sustain a band bending at its interface with the metal, becoming flooded with electrons. This translates into even higher electrical conductivities than the microcrystalline material, but at the expense of lower Seebeck coefficient values.

  20. The relation between heavy metals distribution and particle size fractions in some egyptian soils

    Directory of Open Access Journals (Sweden)

    Monier Morad Wahba

    Full Text Available Soil as a part of the environment receives pollutants from all types of human activities. Heavy metals originating from various organic waste sources and industrial activities accumulate in the soil surface, and their fate depends not only on the types and amounts of waste applied, but on soil properties. Furthermore, soils differ in their retention power for various heavy or trace elements. Twelve soil samples were selected from different sites irrigated with industrial and sewage wastes at Helwan city (Cairo Governorate in the north and El-Saff (Giza Governorate in the south. Separation of clay, silt and sand fractions were carried out. Chemical analyses of trace elements in the form of total and available contents (Fe, Mn, Zn and Pb were determined in each fraction. The obtained results show that the average amounts of heavy metals in different fractions are related to the particle size of the soil especially the fine fraction. Heavy metals content was always in the surface layers higher than sub-surface. All metals were highest in clay fraction followed by silt and sand fractions respectively. This investigation discussed the importance of the fine fractions in the accumulation of heavy metals by coordination number in the lattice structure.

  1. Impact of smoking on guided tissue regeneration using a biocomposite poly (lactic-co-glycolic) acid/sub-micron size hydroxyapatite with a rubber dam as an alternative barrier.

    Science.gov (United States)

    Stramazzotti, D; Coiana, C; Zizzi, A; Spazzafumo, L; Sauro, S; D'Angelo, A B; Rubini, C; Aspriello, S D

    2015-03-01

    The purpose of our study was to critically evaluate the results obtained from a guided tissue regeneration technique after 12 months using a bocomposite poly (lactic-co-glycolic) acid/sub-micron size hydroxyapatite (PLGA/HA) with a rubber dam as a barrier in smoking and non-smoking patients. We selected 36 patients (18 current smokers and 18 non-smokers) diagnosed with chronic advanced periodontitis with a periodontal site (probing depth [PD] >5) amenable to regenerative surgery. Twelve months after surgery, the periodontal parameters were found to have statistically improved, when non-smokers were compared with smokers, in: PD reduction (6.3 ± 2.1 mm vs. 3.6 ± 1.9 mm); CAL gain (4.4 ± 1.1 vs. 2.8 ± 2.2 mm); recession (1.8 ± 1.4 mm vs. 0.8 ± 0.9 mm); and hard tissue fill (4.7 ± 0.8 mm vs. 2.8 ± 2.1 mm). Furthermore, since we found PD baseline differences between groups, smoking seemed not to influence the outcomes achieved (CAL gain and ΔREC) 12 months post surgery with respect to PD baseline. The use of PLGA/HA with a rubber dam significantly improved the periodontal parameters in both smoking and non-smoking subjects. This improvement was nevertheless lower in smokers than the non-smokers, confirming the negative impact of smoking on periodontal regeneration. © The Author(s) 2015.

  2. Metallic ions in organs of rats injected with metallic particles of stainless steel 316L and Ti6Al4V alloy

    Directory of Open Access Journals (Sweden)

    Silvia Helena Giertz

    2010-03-01

    Full Text Available Despite the interest in identifying systemic effects caused by the metallic particles released from long term metallic implants in the body, few works support reliable conclusions about the effects of those particles in organs. The aim of the present work is to look for damages in tissues of liver, kidney, lung and heart of rats submitted to injection of Hank's solution contained particles of Ti6Al4V alloy and Stainless Steel 316L, obtained by metal friction. The particles size ranges from 50 to 200 µm for the Ti alloy and from 100 to 500 µm for the 316L. Tissues isolated from the organs after the euthanasia were prepared and analyzed in an optical microscope and Energy Dispersive Spectrometer (EDS. Lesions caused by an inflammatory response such as strange body epithelioid granuloma and giant cells were found in some of the tissues containing yttrium and aluminum.

  3. Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol.

    Directory of Open Access Journals (Sweden)

    Monique Williams

    Full Text Available Electronic cigarettes (EC deliver aerosol by heating fluid containing nicotine. Cartomizer EC combine the fluid chamber and heating element in a single unit. Because EC do not burn tobacco, they may be safer than conventional cigarettes. Their use is rapidly increasing worldwide with little prior testing of their aerosol.We tested the hypothesis that EC aerosol contains metals derived from various components in EC.Cartomizer contents and aerosols were analyzed using light and electron microscopy, cytotoxicity testing, x-ray microanalysis, particle counting, and inductively coupled plasma optical emission spectrometry.The filament, a nickel-chromium wire, was coupled to a thicker copper wire coated with silver. The silver coating was sometimes missing. Four tin solder joints attached the wires to each other and coupled the copper/silver wire to the air tube and mouthpiece. All cartomizers had evidence of use before packaging (burn spots on the fibers and electrophoretic movement of fluid in the fibers. Fibers in two cartomizers had green deposits that contained copper. Centrifugation of the fibers produced large pellets containing tin. Tin particles and tin whiskers were identified in cartridge fluid and outer fibers. Cartomizer fluid with tin particles was cytotoxic in assays using human pulmonary fibroblasts. The aerosol contained particles >1 µm comprised of tin, silver, iron, nickel, aluminum, and silicate and nanoparticles (<100 nm of tin, chromium and nickel. The concentrations of nine of eleven elements in EC aerosol were higher than or equal to the corresponding concentrations in conventional cigarette smoke. Many of the elements identified in EC aerosol are known to cause respiratory distress and disease.The presence of metal and silicate particles in cartomizer aerosol demonstrates the need for improved quality control in EC design and manufacture and studies on how EC aerosol impacts the health of users and bystanders.

  4. The role of particle-size soil fractions in the adsorption of heavy metals

    Science.gov (United States)

    Mandzhieva, Saglara; Minkina, Tatiana; Pinsky, David; Batukaev, Abdulmalik; Kalinitchenko, Valeriy; Sushkova, Svetlana; Chaplygin, Viktor; Dikaev, Zaurbek; Startsev, Viktor; Bakoev, Serojdin

    2014-05-01

    Ion-exchange adsorption phenomena are important in the immobilization of heavy metals (HMs) by soils. Numerous works are devoted to the study of this problem. However, the interaction features of different particle-size soil fractions and their role in the immobilization of HMs studied insufficiently. Therefore, the assessment of the effect of the particle-size distribution on the adsorption properties of soils is a vital task. The parameters of Cu2+, Pb2+ and Zn2+ adsorption by chernozems of the south of Russia and their particle-size fractions were studied. In the particle-size fractions separated from the soils, the concentrations of Cu2+, Pb2+, and Zn2 decreased with the decreasing particle size. The parameters of the adsorption values of k (the constant of the affinity)and Cmax.(the maximum adsorption of the HMs) characterizing the adsorption of HMs by the southern chernozem and its particle-size fractions formed the following sequence: silt > clay > entire soil. The adsorption capacity of chernozems for Cu2+, Pb2+, and Zn2+ depending on the particle-size distribution decreased in the following sequence: clay loamy ordinary chernozem clay loamy southern chernozem> loamy southern chernozem> loamy sandy southern chernozem. According to the parameters of the adsorption by the different particle-size fractions, the heavy metal cations form a sequence analogous to that obtained for the entire soils: Cu2+ ≥ Pb2+ > Zn2+. The parameters of the heavy metal adsorption by similar particle-size fractions separated from different soils decreased in the following order: clay loamy chernozem> loamy chernozem> loamy sandy chernozem. The analysis of the changes in the parameters of the Cu2+, Pb2+, and Zn2+ adsorption by the studied soils and their particle-size fractions showed that the extensive adsorption characteristic - the maximum adsorption (Cmax.) - is a less sensitive parameter characterizing the adsorption capacity of the soils than the intensive characteristic of

  5. On Absorption-Enhanced Organic Photovoltaic By Incorporating Metallic Nano Pyramid Particles

    Science.gov (United States)

    Qasem, Hussamaldeen Saif

    A lattice structure of metallic Nano pyramids (NPY) particles was planted on the interface between hole transport layer (HTL) and the transparent conductive layer (TCL) of an organic photovoltaic (OPV) cell. Standard metal evaporation along with Nano sphere lithography was used to grow the metallic NPY mesh structure. Silver (Ag) and Gold (Au) were the primary choice of the NPY mesh structure due to the excellent overlap of their peak localized surface Plasmon resonance (LSPR) frequency with the active layer absorption wavelengths. The current-voltage curve displayed an improvement in the efficiency and fill factor values of OPVs that used NPY lattice structure over devices that used regular sphere-shaped Nano particles. Despite the better-shaped and strong (LSPR) peak frequency of the Ag NPY lattice structure, Au NPY lattice structure exhibited an enhanced absorption and overall efficiency, which was owed to the wider (LSPR) frequency peak that Au possesses. The effect of NPY lattice structure could be further investigated with several approaches such as using different NPY materials, using core-shill approach, and growing the NPY on different layers or interfaces.

  6. Slow waves in microchannel metal waveguides and application to particle acceleration

    Directory of Open Access Journals (Sweden)

    L. C. Steinhauer

    2003-06-01

    Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6  mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  7. Slow waves in microchannel metal waveguides and application to particle acceleration

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2003-06-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  8. Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park.

    Science.gov (United States)

    Li, Haiyan; Shi, Anbang; Zhang, Xiaoran

    2015-06-01

    Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size (particle size distribution, as indicated by the variation of size fraction with the increase of dry days. The amount of heavy metal (i.e., Cu, Zn, Pb and Cd) content was the largest in particles with small size (particles was 74.7%, 55.5%, 56.6% and 71.3%, respectively. Heavy metals adsorbed in sediments may mainly be contributed by road traffic emissions. The contamination levels of Pb and Cd were higher than Cu and Zn on the basis of the mean heavy metal contents. Specifically, the geoaccumulation index (Igeo) decreased in the order: Cd>Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu. Copyright © 2015. Published by Elsevier B.V.

  9. Numerical simulation on magnetic assembled structures of iron-based metallic particles within MMCs by a homogeneous strong magnetic field

    Science.gov (United States)

    Liu, Chunwei; Sun, Zhi; Zheng, Lichun; Huang, Shuigen; Blanpain, Bart; Guo, Muxing

    2015-09-01

    Particle-reinforced metal matrix composites (MMCs) have excellent physicochemical properties as structural materials. The morphology and distribution control of reinforcement particles during the fabrication of MMCs are difficult-but-critical-to-achieve required properties of the materials. This research demonstrates a possibility to quantitatively control the distribution of particles in the metal matrix by applying a magnetic field. A 2D numerical model is developed and applied to evaluate the behaviour of Fe-based metallic particles in aluminum MMCs. By combination of 2D simulation with intersectional directions, this model also provides some hints for 3D practice. The assembled structure is found to be governed by the external magnetic field orientation, magnetic flux density and magnetic susceptibility of the particles. Both behaviours of particle agglomeration and dispersion are quantitatively characterized in different conditions. By using a strong magnetic field, it is found that assembled structures of weakly magnetic particles can be effectively manipulated. Therefore, it can be expected to fabricate particle-enhanced metal matrix composites/ceramics/glass with substantial improvements in physical and chemical properties by using a magnetic field.

  10. [Distribution characteristics and environmental significance of heavy metals in soil particle size fractions from tropical forests in China].

    Science.gov (United States)

    Gong, Cang; Xu, Dian-Dou; Cheng, Hang-Xin; Ren, Ya-Ge; Liu, Zhi-Ming; Liu, Ying-Han; Liu, Fei; Nie, Hai-Feng; Zheng, Xiang; Ma, Ling-Ling

    2013-03-01

    Three tropical forest soils were collected from Haikou, Qionghai and Tunchang in Hainan Island. Soil particle size fractionations were conducted using the standard dry-sieving procedure. Distribution of heavy metals in bulk samples and particle size fractions was determined by ICP-MS. The distribution characteristics and the response to organic carbon and iron were discussed. The results showed that the distribution of heavy metals was highly associated with the particle size fractions and variable patterns were found, which decreased with the increasing size. The accumulation of Cr, Ni, Cu, Zn, Cd and Cd was predominantly contributed by the particles finer than particle size of 53-1 000 microm. Generally, the microaggregate (size fractions were controlled by the organic carbon and iron contents, which increased with the decreasing particle size.

  11. Particle number projecting method for description of pairing effects in metal clusters

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, N. [Khlopin Radium Institute, St. Peterburg (Russian Federation); Nesterenko, V.; Pashkevich, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics; Frauendorf, S. [Institut fuer Kern- und Hadronenphysik, Forshungszentrum Rossendorf, Dresden (Germany)

    1996-05-01

    The particle number projecting method for the description of pairing effects in metal clusters is proposed. In contrast with the Bardeen-Cooper-Schrieffer method (BCS) which does not conserve the particle number (thus not providing the necessary accuracy of calculations for small clusters) and has no solutions at sufficiently weak pairing, the projecting method can be applied to both small and large clusters with any pairing strength. As an example, the projection method is used to check the assertion on the pairing origin of the odd-even staggering (OES) in the ionization potentials (IP) of sodium clusters. Both effects of pairing and shape deformation are taken into account simultaneously. In general, the results obtained show that the existence of pairing in sodium clusters is doubtful.

  12. Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; Keudell, Achim von [RD Plasmas with Complex Interactions, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum (Germany)

    2013-10-15

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP)

  13. Effect of different air-abrasion particles on metal-ceramic bond strength

    OpenAIRE

    Külünk, Tolga; Kurt, Murat; Ural, Çağrı; Külünk, Şafak; Baba, Seniha

    2011-01-01

    Background/purpose: Chipping and delaminating of veneering ceramics are critical problems in the fabrication of metal-ceramic restorations. The purpose of this study was to evaluate the effect of different air-abrasion particles on the shear bond strength of a ceramic to nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys. Materials and methods: Forty square specimens (10 mm × 10 mm × 1.5 mm) were cast for each Ni-Cr and Co-Cr alloys. Specimens were divided into four groups for the ...

  14. Metal particle emissions in the exhaust stream of diesel engines: an electron microscope study.

    Science.gov (United States)

    Liati, Anthi; Schreiber, Daniel; Dimopoulos Eggenschwiler, Panayotis; Arroyo Rojas Dasilva, Yadira

    2013-12-17

    Scanning electron microscopy and transmission electron microscopy were applied to investigate the morphology, mode of occurrence and chemical composition of metal particles (diesel ash) in the exhaust stream of a small truck outfitted with a typical after-treatment system (a diesel oxidation catalyst (DOC) and a downstream diesel particulate filter (DPF)). Ash consists of Ca-Zn-P-Mg-S-Na-Al-K-phases (lube-oil related), Fe, Cr, Ni, Sn, Pb, Sn (engine wear), and Pd (DOC coating). Soot agglomerates of variable sizes (1-5 μm, exceptionally 13 μm), rarely engine wear and escape into the atmosphere.

  15. Ni-functionalized submicron mesoporous silica particles as a sorbent for metal affinity chromatography.

    Science.gov (United States)

    Kurdyukov, Dmitry A; Chernova, Ekaterina N; Russkikh, Yana V; Eurov, Daniil A; Sokolov, Vasily V; Bykova, Anna A; Shilovskikh, Vladimir V; Keltsieva, Olga A; Ubyivovk, Eugenii V; Anufrikov, Yuri A; Fedorova, Anna V; Selyutin, Artem A; Sukhodolov, Nicolay G; Podolskaya, Ekaterina P; Golubev, Valery G

    2017-09-01

    In this research, a novel IMAC sorbent with high specificity for chlorine-containing compounds was developed. Ni-functionalized monodisperse spherical mesoporous silica particles of 500±25nm diameter were synthesized and their metal affinity properties were studied with the use of diclofenac as the model substance. The particles were aggregatively stable in the pH range of 3-12. The sorbent demonstrated a high adsorption capacity (0.60±0.06μg of DCF per 1mg of the sorbent) and high adsorption/desorption rate (20 and 5min was enough for the sorbent saturation and desorption of DCF, correspondingly). A mixture of eluents with addition of PFOS providing the almost complete recovery (98%) of diclofenac was first proposed. The monodispersity and the high sedimentation and aggregative stability of the particles provide the formation of a stable hydrosol even under ultrasound treatment which makes the mSiO2/Ni particles suitable for batch chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Control of Partial Coalescence of Self-Assembled Metal Nano-Particles across Lyotropic Liquid Crystals Templates towards Long Range Meso-Porous Metal Frameworks Design.

    Science.gov (United States)

    Dumée, Ludovic F; Lemoine, Jean-Baptiste; Ancel, Alice; Hameed, Nishar; He, Li; Kong, Lingxue

    2015-10-26

    The formation of purely metallic meso-porous metal thin films by partial interface coalescence of self-assembled metal nano-particles across aqueous solutions of Pluronics triblock lyotropic liquid crystals is demonstrated for the first time. Small angle X-ray scattering was used to study the influence of the thin film composition and processing conditions on the ordered structures. The structural characteristics of the meso-structures formed demonstrated to primarily rely on the lyotropic liquid crystal properties while the nature of the metal nano-particles used as well as the their diameters were found to affect the ordered structure formation. The impact of the annealing temperature on the nano-particle coalescence and efficiency at removing the templating lyotropic liquid crystals was also analysed. It is demonstrated that the lyotropic liquid crystal is rendered slightly less thermally stable, upon mixing with metal nano-particles and that low annealing temperatures are sufficient to form purely metallic frameworks with average pore size distributions smaller than 500 nm and porosity around 45% with potential application in sensing, catalysis, nanoscale heat exchange, and molecular separation.

  17. The role of soil's particle-size fractions in the adsorption of heavy metals

    Directory of Open Access Journals (Sweden)

    Saglara Mandzhieva

    2014-08-01

    Full Text Available The parameters of adsorption of Cu2+, Pb2+, and Zn2+ cations by southern chernozem and their particle-size fractions were studied. The adsorption of metals by soils and the strength of their fixation on the surface of soil particles under both mono- and poly-element contamination decreased with the decreasing proportion of fine fractions in the soil. The aim of this work was to study the effect of the particle-size distribution and the silt and physical clay fractions on the adsorption of copper, lead, and zinc by chernozems. The objects of study included the upper humus horizons of different southern chernozems of the Rostov oblast. To study the ion-exchange adsorption of the Cu2+, Pb2+, and Zn2+ cations, the soil in the natural ionic form was disaggregated using a pestle with a rubber head and sieved through a 1mm sieve. The soil samples were treated with solutions of Cu2+, Pb2+, and Zn2+ nitrates and acetates at the separate and simultaneous presence of heavy metals (HMs. In the solutions with the simultaneous presence of HMs, their molar concentrations were similar. The concentrations of the initial solutions varied in the range from 0.05 to 1 mM/l. The soil: solution ratio was 1:10. The contents of HMs in the filtrates were determined by atomic absorption spectrophotometry. The contents of adsorbed HM cations were calculated from the difference between the metal concentrations in the initial and equilibrium solutions. The increase in the degree of dispersion of the particle-size fractions in similar soils resulted not only in an increase in the content of adsorbed HMs but also in an enhancement of their fixation on the surface of the fine particles. Therefore, the adsorption capacity of the Lower Don soils for Cu2+, Pb2+, and Zn2+ decreased in the following sequence: clay loamy southern chernozem > loamy southern chernozem > loamy sandy southern chernozem. This was related to the qualitative differences in the mineralogy and chemistry of

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

    CERN Document Server

    Plettner, Tomas; Spencer, James; Wisdom, Jeffrey

    2005-01-01

    Laser driven particle accelerators based on the current generation of lasers will require sub-micron control of the laser field as well as precise beam guiding. Hence the fabrication techniques that allow integrating both elements into an accelerator-on-chip format become critical for the success of such particle accelerators. Micromachining technology for silicon has been shown to be one such feasible technology in PAC2003 but with a variety of complications on the laser side. Fortunately, in recent years the fabrication of transparent ceramics has become an interesting technology that could be applied for laser-particle accelerators in several ways. We discuss this area, its advantages such as the range of materials it provides and various ways to implement it followed by some different test examples that have been considered. One important goal of this approach is an integrated system that could avoid the necessity of having to inject either laser or particle pulses into these structures.

  19. Metal speciation dynamics in dispersions of soft colloidal ligand particles under steady-state laminar flow condition.

    Science.gov (United States)

    Duval, Jérôme F L; Qian, Shizhi

    2009-11-19

    A theory is presented for metal speciation dynamics in a swarm of soft, spherical core-hell colloidal ligand particles under steady-state laminar flow condition. Mass transfer and subsequent complexation of metal species within the reactive, permeable particle shell are governed by the interplay between (i) convective-diffusion of free metal ions M within and around the shell where ligands L are distributed, and (ii) kinetics of ML complex formation/dissociation in the shell. The local concentrations of metal M and complex ML are determined by the convective-diffusion equations with appropriate chemical source term and full account of radial and angular concentration polarization contributions. The steady-state flow field is determined from the solution of Navier-tokes equation including convective acceleration term for the fluid external to the particle, and from Brinkman equation for the internal fluid flow. The confined location of ligands within the particle shell leads to ML formation/dissociation rate constants (denoted as ka* and kd*, respectively) that differ significantly from their counterparts (ka and kd) defined for homogeneous ligand distribution throughout the solution. The relationship between ka,d* and ka,d is derived from the numerical evaluation of the spatial, time-dependent distributions of free and bound metal within and/or outside the particle. The dramatic dependence of ka,d* on hydrodynamic particle softness, Péclet number, soft surface layer thickness, and particle radius are analyzed in the steady-state nonequilibrium chemical regime within the context of dynamic features for colloidal complexes. The analysis covers the limiting cases of hydrodynamically impermeable, hard particles where binding sites are located at the very surface of the particle core (e.g., functionalized latex colloids) and free draining, polymeric ligand particles devoid of a hard core (e.g., porous gel particles). The formalism further applies to any values of the

  20. Metal-based magnetic fluids with core-shell structure FeB@SiO2 amorphous particles.

    Science.gov (United States)

    Yu, Mengchun; Bian, Xiufang; Wang, Tianqi; Wang, Junzhang

    2017-09-27

    FeB@SiO2 amorphous particles were firstly introduced into Ga85.8In14.2 alloys to prepare metal-based magnetic fluids. The morphology of the FeB amorphous particles is spherical with an average particle size of about 190 nm. The shape of the particles is regular and the particle size is homogeneous. Stable core-shell structure SiO2 modified FeB amorphous particles are obtained and the thickness of the SiO2 coatings is observed to be about 40 nm. The results of VSM confirm that the saturation magnetization of the FeB amorphous particles is 131.5 emu g-1, which is almost two times higher than that of the Fe3O4 particles. The saturation magnetization of the FeB@SiO2 amorphous particles is 106.9 emu g-1, an approximate decrease of 18.7% due to the non-magnetic SiO2 coatings. The results from the torsional oscillation viscometer show that the metal-based magnetic fluids with FeB amorphous particles exhibit a desirable high temperature performance and are ideal candidates for high temperature use.

  1. Sub-micron indent induced plastic deformation in copper and irradiated steel; Deformation plastique induite par l'essai d'indentation submicronique, dans le cuivre et l'acier 316L irradie

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Ch

    1999-07-01

    In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu (001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg. C - 600 deg. C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM

  2. Tunable potential well for plasmonic trapping of metallic particles by bowtie nano-apertures

    Science.gov (United States)

    Lu, Yu; Du, Guangqing; Chen, Feng; Yang, Qing; Bian, Hao; Yong, Jiale; Hou, Xun

    2016-09-01

    In this paper, the tunable optical trapping dependence on wavelength of incident beam is theoretically investigated based on numerical simulations. The Monte Carlo method is taken into account for exploring the trapping characteristics such as average deviation and number distribution histogram of nanoparticles. It is revealed that both the width and the depth of potential well for trapping particles can be flexibly adjusted by tuning the wavelength of the incident beam. In addition, incident wavelengths for the deepest potential well and for the strongest stiffness at bottom are separated. These phenomena are explained as the strong plasmon coupling between tweezers and metallic nanoparticles. In addition, required trapping fluence and particles’ distributions show distinctive properties through carefully modifying the incident wavelengths from 1280 nm to 1300 nm. Trapping with lowest laser fluence can be realized with 1280 nm laser and trapping with highest precision can be realized with 1300 nm laser. This work will provide theoretical support for advancing the manipulation of metallic particles and related applications such as single-molecule fluorescence and surface enhanced Raman spectroscopy.

  3. Effects of particle composition and species on toxicity of metallic nanomaterials in aquatic organisms.

    Science.gov (United States)

    Griffitt, Robert J; Luo, Jing; Gao, Jie; Bonzongo, Jean-Claude; Barber, David S

    2008-09-01

    Metallic nanoparticles are among the most widely used types of engineered nanomaterials; however, little is known about their environmental fate and effects. To assess potential environmental effects of engineered nanometals, it is important to determine which species are sensitive to adverse effects of various nanomaterials. In the present study, zebrafish, daphnids, and an algal species were used as models of various trophic levels and feeding strategies. To understand whether observed effects are caused by dissolution, particles were characterized before testing, and particle concentration and dissolution were determined during exposures. Organisms were exposed to silver, copper, aluminum, nickel, and cobalt as both nanoparticles and soluble salts as well as to titanium dioxide nanoparticles. Our results indicate that nanosilver and nanocopper cause toxicity in all organisms tested, with 48-h median lethal concentrations as low as 40 and 60 microg/L, respectively, in Daphnia pulex adults, whereas titanium dioxide did not cause toxicity in any of the tests. Susceptibility to nanometal toxicity differed among species, with filter-feeding invertebrates being markedly more susceptible to nanometal exposure compared with larger organisms (i.e., zebrafish). The role of dissolution in observed toxicity also varied, being minor for silver and copper but, apparently, accounting for most of the toxicity with nickel. Nanoparticulate forms of metals were less toxic than soluble forms based on mass added, but other dose metrics should be developed to accurately assess concentration-response relationships for nanoparticle exposures.

  4. Exposure vs toxicity levels of airborne quartz, metal and carbon particles in cast iron foundries.

    Science.gov (United States)

    Moroni, Beatrice; Viti, Cecilia; Cappelletti, David

    2014-01-01

    Aerosol dust samples and quartz raw materials from different working stations in foundry plants were characterized in order to assess the health risk in this working environment. Samples were analysed by scanning and transmission electron microscopy coupled with image analysis and microanalysis, and by cathodoluminescence spectroscopy. In addition, the concentration and the solubility degree of Fe and other metals of potential health effect (Mn, Zn and Pb) in the bulk samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Overall, the results indicate substantial changes in quartz crystal structure and texture when passing from the raw material to the airborne dust, which include lattice defects, non-bridging oxygen hole centres and contamination of quartz grains by metal and/or graphite particles. All these aspects point towards the relevance of surface properties on reactivity. Exposure doses have been estimated based on surface area, and compared with threshold levels resulting from toxicology. The possible synergistic effects of concomitant exposure to inhalable magnetite, quartz and/or graphite particles in the same working environment have been properly remarked.

  5. An ultra-thin Schottky diode as a transmission particle detector for biological microbeams

    Science.gov (United States)

    Harken, Andrew; Randers-Pehrson, Gerhard; Attinger, Daniel; Brenner, David J.

    2013-01-01

    We fabricated ultrathin metal-semiconductor Schottky diodes for use as transmission particle detectors in the biological microbeam at Columbia University’s Radiological Research Accelerator Facility (RARAF). The RARAF microbeam can deliver a precise dose of ionizing radiation in cell nuclei with sub-micron precision. To ensure an accurate delivery of charged particles, the facility currently uses a commercial charged-particle detector placed after the sample. We present here a transmission detector that will be placed between the particle accelerator and the biological specimen, allowing the irradiation of samples that would otherwise block radiation from reaching a detector behind the sample. Four detectors were fabricated with co-planar gold and aluminum electrodes thermally evaporated onto etched n-type crystalline silicon substrates, with device thicknesses ranging from 8.5 μm – 13.5 μm. We show coincident detections and pulse-height distributions of charged particles in both the transmission detector and the commercial detector above it. Detections are demonstrated at a range of operating conditions, including incoming particle type, count rate, and beam location on the detectors. The 13.5 μm detector is shown to work best to detect 2.7 MeV protons (H+), and the 8.5 μm detector is shown to work best to detect 5.4 MeV alpha particles (4He++). The development of a transmission detector enables a range of new experiments to take place at RARAF on radiation-stopping samples such as thick tissues, targets that need immersion microscopy, and integrated microfluidic devices for handling larger quantities of cells and small organisms. PMID:24058378

  6. Surface passivation of silicon nanowires based metal nano-particle assisted chemical etching for photovoltaic applications

    Science.gov (United States)

    Ben Rabha, Mohamed; Khezami, Lotfi; Jemai, Abdelbasset Bessadok; Alhathlool, Raed; Ajbar, Abdelhamid

    2017-03-01

    Metal Nano-particle Assisted Chemical Etching (MNpACE) is an extraordinary developed wet etching method for producing uniform semiconductor nanostructure (silicon nanowires) from patterned metallic film on crystalline silicon surface. The metal films facilitate the etching in HF and H2O2 solution and produce silicon nanowires (SiNWs).The creation of different SiNWs morphologies by changing the etching time and its effects on optical and optoelectronic properties was investigated. The combination effect of formed SiNWs and stain etching treatment in acid (HF/HNO3/H2O) solution on the surface morphology of Si wafers as well as on the optical and optoelectronic properties especially a PL response at 640 nm are presented. As a results, the effective lifetime (τeff) and surface recombination velocity (Seff) evolution of SiNWs after stain etching treatment showed significant improvements and less than 1% reflectance was achieved over the wavelength range of 400-800 nm and more than 36% reduction was observed compared to untreated surface. It has, thus, been demonstrated that all these factors may lead to improved energy efficiency from 8% to nearly 14.2% for a cell with SiNWs treated in acid (HF/HNO3/H2O) solution.

  7. Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes

    Energy Technology Data Exchange (ETDEWEB)

    Yurekli, Yilmaz, E-mail: yilmazyurekli@gmail.com

    2016-05-15

    Highlights: • NaX addition significantly enhanced water hydraulic permeability of the membrane. • Metal exchange capacity of the membrane increased with the NaX content. • Hybrid membrane was efficient for the solutions with low metal concentrations - Abstract: In this study, the adsorption and the filtration processes were coupled by a zeolite nanoparticle impregnated polysulfone (PSf) membrane which was used to remove the lead and the nickel cations from synthetically prepared solutions. The results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis indicated that the synthesized zeolite nanoparticles, using conventional hydrothermal method, produced a pure NaX with ultrafine and uniform particles. The performance of the hybrid membrane was determined under dynamic conditions. The results also revealed that the sorption capacity as well as the water hydraulic permeability of the membranes could both be improved by simply tuning the membrane fabricating conditions such as evaporation period of the casting film and NaX loading. The maximum sorption capacity of the hybrid membrane for the lead and nickel ions was measured as 682 and 122 mg/g respectively at the end of 60 min of filtration, under 1 bar of transmembrane pressure. The coupling process suggested that the membrane architecture could be efficiently used for treating metal solutions with low concentrations and transmembrane pressures.

  8. Mass production of polymer nano-wires filled with metal nano-particles.

    Science.gov (United States)

    Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

    2017-08-17

    Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

  9. Redox activity and chemical interactions of metal oxide nano- and micro-particles with dithiothreitol (DTT).

    Science.gov (United States)

    Nicolas, Johny; Jaafar, Malek; Sepetdjian, Elizabeth; Saad, Walid; Sioutas, Constantinos; Shihadeh, Alan; Saliba, Najat A

    2015-11-01

    The wide application and production of nanotechnology have increased the interest in studying the toxicity of nano- and micro-sized particles escaping into air from various aspects of the production process. Metal oxides (MOs) are one particular class of particles that exist abundantly in ambient PM. Studies show an emphasis on biological mechanisms by which inhalation exposure to MOs leads to disease. However, different biological assays provide different redox activity rankings making it difficult to assess the contributions of various MOs to measures of aggregate toxicity in multi-pollutant systems such as ambient PM. Therefore, research to evaluate the chemical interaction between these particles and molecules that are relevant to cellular redox activity can help in establishing indicators of reactivity. In particular, this study assesses the redox activity of six MOs mainly emitted from anthropogenic industrial activities using the dithiothreitol (DTT) assay. DTT is commonly used in acellular assays due to its analogous structure to cellular glutathione. The structural and chemical behaviors between active MOs and DTT were elucidated using FTIR, NMR, and BET methods. The results indicate that the health risk (redox activity) associated with MOs is mainly a function of their surface reactivity demonstrated by the ability of the oxidized (S-H) bond in DTT to form a stable bond with the MO surface.

  10. Metal copper films deposited on cenosphere particles by magnetron sputtering method

    Science.gov (United States)

    Yu, Xiaozheng; Xu, Zheng; Shen, Zhigang

    2007-05-01

    Metal copper films with thicknesses from several nanometres to several micrometres were deposited on the surface of cenosphere particles by the magnetron sputtering method under different working conditions. An ultrasonic vibrating generator equipped with a conventional magnetron sputtering apparatus was used to prevent the cenosphere substrates from accumulating during film growth. The surface morphology, the chemical composition, the average grain size and the crystallization of cenosphere particles were characterized by field emission scanning electron microscopy (FE-SEM), inductively coupled plasma-atom emission spectrometer, x-ray photoelectron spectroscopy and x-ray diffraction (XRD) analysis, respectively, before and after the plating process. The results indicate that the copper films were successfully deposited on cenosphere particles. It was found from the FE-SEM results that the films were well compacted and highly uniform in thickness. The XRD results show that the copper film coated on cenospheres has a face centred cubic structure and the crystallization of the film sample increases with increasing sputtering power.

  11. Metal copper films deposited on cenosphere particles by magnetron sputtering method

    Energy Technology Data Exchange (ETDEWEB)

    Yu Xiaozheng [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing, 100083 (China); Xu Zheng [General Research Institute for Non-ferrous Metals, Beijing 100088 (China); Shen Zhigang [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing, 100083 (China)

    2007-05-07

    Metal copper films with thicknesses from several nanometres to several micrometres were deposited on the surface of cenosphere particles by the magnetron sputtering method under different working conditions. An ultrasonic vibrating generator equipped with a conventional magnetron sputtering apparatus was used to prevent the cenosphere substrates from accumulating during film growth. The surface morphology, the chemical composition, the average grain size and the crystallization of cenosphere particles were characterized by field emission scanning electron microscopy (FE-SEM), inductively coupled plasma-atom emission spectrometer, x-ray photoelectron spectroscopy and x-ray diffraction (XRD) analysis, respectively, before and after the plating process. The results indicate that the copper films were successfully deposited on cenosphere particles. It was found from the FE-SEM results that the films were well compacted and highly uniform in thickness. The XRD results show that the copper film coated on cenospheres has a face centred cubic structure and the crystallization of the film sample increases with increasing sputtering power.

  12. Mobilization and transport of metal-rich colloidal particles from mine tailings into soil under transient chemical and physical conditions.

    Science.gov (United States)

    Lu, Cong; Wu, Yaoguo; Hu, Sihai; Raza, Muhammad Ali; Fu, Yilin

    2016-04-01

    Exposed mine tailing wastes with considerable heavy metals can release hazardous colloidal particles into soil under transient chemical and physical conditions. Two-layered packed columns with tailings above and soils below were established to investigate mobilization and transport of colloidal particles from metal-rich mine tailings into soil under transient infiltration ionic strength (IS: 100, 20, 2 mM) and flow rate (FR: 20.7, 41, and 62.3 mm h(-1)), with Cu and Pb as representatives of the heavy metals. Results show that the tailing particles within the colloidal size (below 2 μm) were released from the columns. A step-decrease in infiltration IS and FR enhanced, whereas a step-increase in the IS and FR restrained the release of tailing particles from the column. The effects of step-changing FR were unexpected due to the small size of the released tailing particles (220-342 nm, being not sensitive to hydrodynamic shear force), the diffusion-controlled particle release process and the relatively compact pore structure. The tailing particles present in the solution with tested IS were found negatively charged and more stable than soil particles, which provides favorable conditions for tailing particles to be transported over a long distance in the soil. The mobilization and transport of Cu and Pb from the tailings into soil were mediated by the tailing particles. Therefore, the inherent toxic tailing particles could be considerably introduced into soil under certain conditions (IS reduction or FR decrease), which may result in serious environmental pollution.

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

    Energy Technology Data Exchange (ETDEWEB)

    Plettner, T.; Gaume, R.; Wisdom, J.; /Stanford U., Phys. Dept.; Spencer, J.; /SLAC

    2005-06-07

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

  14. The Metal-Support Interaction Concerning the Particle Size Effect of Pd/Al2O3on Methane Combustion.

    Science.gov (United States)

    Murata, Kazumasa; Mahara, Yuji; Ohyama, Junya; Yamamoto, Yuta; Arai, Shigeo; Satsuma, Atsushi

    2017-12-11

    The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/θ, α-Al 2 O 3 with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/γ-Al 2 O 3 increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spectroscopy and spherical aberration-corrected scanning/transmission electron microscopy, the dependence of catalytic activity on Pd particle size and the alumina crystalline phase was due to the fraction of step sites on Pd particle surface. The difference in fraction of the step site is derived from the particle shape, which varies not only with Pd particle size but also with the strength of metal-support interaction. Therefore, this interaction perturbs the particle size effect of Pd/Al 2 O 3 for methane combustion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Hydrogen effect in (Al-Ti)-SiC particle metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Solovioff, G.; Eliezer, D. (Dept. of Materials Engineering, Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel)); Lavernia, E.J. (Dept. of Mechanical and Aerospace Engineering, California Univ., Irvine (United States))

    1992-12-30

    The development of advanced air frames and propulsion systems has generated significant research and development activity in the area of light-weight high temperature intermetallic alloys. Exposure to hydrogen results in the severe embrittlement of many intermetallics. In the present study the microstructure of spray-atomized and codeposited metal matrix composites (MMCs) were characterized following hydrogen charging. The results show that, under severe conditions such as exposure to NaCl solutions at cathodic charging conditions, initial crack propagation in (Al-Ti)-SiC[sub p] MMCs (which SiC[sub p] represents SiC particles) occurs without any applied stress. It is also important to note that hydrogen charging increases the amount of hydrogen in the material. There is always the possibility of preferential hydrogen accumulation at the large number of incoherent interfaces between the reinforcement particulates and the matrix. The phenomenology of hydrogen embrittlement and possible mechanisms of embrittlement are discussed. (orig.).

  16. Electrical four-point probing of spherical metallic thin films coated onto micron sized polymer particles

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Sigurd R., E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no; Stokkeland, August Emil; Zhang, Zhiliang; He, Jianying, E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Kristiansen, Helge [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway); Njagi, John; Goia, Dan V. [Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5814 (United States); Redford, Keith [Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway)

    2016-07-25

    Micron-sized metal-coated polymer spheres are frequently used as filler particles in conductive composites for electronic interconnects. However, the intrinsic electrical resistivity of the spherical thin films has not been attainable due to deficiency in methods that eliminate the effect of contact resistance. In this work, a four-point probing method using vacuum compatible piezo-actuated micro robots was developed to directly investigate the electric properties of individual silver-coated spheres under real-time observation in a scanning electron microscope. Poly(methyl methacrylate) spheres with a diameter of 30 μm and four different film thicknesses (270 nm, 150 nm, 100 nm, and 60 nm) were investigated. By multiplying the experimental results with geometrical correction factors obtained using finite element models, the resistivities of the thin films were estimated for the four thicknesses. These were higher than the resistivity of bulk silver.

  17. Particle layering in the ceramic-metal thin film Pt-Al2O3

    Science.gov (United States)

    Gibaud, A.; Hazra, S.; Sella, C.; Laffez, P.; Désert, A.; Naudon, A.; van Tendeloo, G.

    2001-05-01

    Experiments performed by x-ray reflectivity, grazing incidence small angle x-ray scattering (GISAXS), and transmission electron microscopy (TEM) on a cosputtered nanocermet thin film of Pt-Al2O3 are presented. It is shown that the morphology of such a heterogeneous material can be well interpreted by combining the information obtained from the three techniques. In particular, the layering of metal nanoparticles in the immediate vicinity of the substrate is clearly evidenced. GISAXS results are interpreted via a model which yields spherical nanoparticles of diameter 2R=3.1 nm, separated on the average by a distance of 5.8 nm. The evidence for the layering of particles close to the substrate is deduced from the analysis of the specular reflectivity and probed directly by TEM.

  18. Heavy metals distribution characteristics in different particle size of bottom ash after agglomeration/defluidization at various fluidization parameters

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chiou-Liang; Yeh, T.Y. [Department of Civil and Environmental Engineering, National University of Kaohsiung, Kaohsiung, 811, Nan-Tzu District (China)

    2010-04-15

    This study examined the effects of variations in alkali and alkaline earth metal content, bed material diameter, static bed height and gas velocity in a fluidized-bed combustion process to understand the distribution of heavy metals in bottom ash after agglomeration/defluidization. A smaller diameter bed material increased the relative abundance of small particle sizes in the bottom ash due to attrition and thermal impact at high temperature. The addition of Na led to an increase in the large particle abundance of the bottom ash, likely due to the formation of a eutectic with a low melting point, causing agglomeration. The addition of Ca inhibited the agglomeration/defluidization and increased the abundance of large particles in the bottom ash. In general, heavy metal concentrations increased when the bottom ash size was smaller than 0.59 mm and larger than 0.84 mm. Regarding the different fluidization parameters, the bottom ash had the lowest concentration of heavy metals at 1.5 U{sub mf}, an H/D of 2.1 and a bed material (silica) particle size of 0.645 mm. The concentrations of heavy metals in the bottom ash after Ca addition were higher than of those without Na or with Na only. Addition of Ca prolonged the operation time of fluidization and increased the feed quantity of heavy metal, helping the bed material adsorb more heavy metal. Therefore, the addition of Ca not only prolonged the fluidization time, reducing agglomeration/defluidization, but also resulted in a higher adsorption of heavy metals by the bed material, reducing their emission. (author)

  19. Electrical currents resulting from reduction/oxidation processes of tested particles on electrodes modified with metal-containing polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Malev, V.V., E-mail: elchem@rbcmail.r [Department of Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 Petergof, St. Petersburg (Russian Federation); Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr. 4, 194064 St. Petersburg (Russian Federation); Levin, O.V. [Department of Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 Petergof, St. Petersburg (Russian Federation)

    2011-04-01

    Metal-containing films are considered as systems including a multitude of microelectrodes, the role of which is played by metal clusters distributed in both the film interior and film interfaces. In the case of electrode reactions occurring exclusively on the surface of such metal inclusions and the film thickness significantly exceeding clusters' radii, it is shown that the concentration of species participating in such processes (tested particles, further on) satisfies a diffusion equation complicated with an accompanying electrochemical reaction. By assuming reversibility of the electron transfer processes between polymer fragments, one can arrive at solutions of the derived equation and calculate the corresponding currents resulting from tested particles' reactions. The role of such factors of inclusion of metal clusters into conducting polymer films, as its density and inhomogeneity is discussed in the context of their influence on the measured currents of reduction/oxidation processes of tested particles. Non-stationary effects that might be observed in cycling voltammetry and potential clamp measurements with electrodes modified by metal-containing films are also analyzed. The performed analysis shows that electrochemical properties of the modified electrodes in question practically coincide with those of the electrodes made of the corresponding metals and immersed into the same solutions.

  20. Particle-size dependence on metal(loid) distributions in mine wastes: Implications for water contamination and human exposure

    Science.gov (United States)

    Kim, C.S.; Wilson, K.M.; Rytuba, J.J.

    2011-01-01

    The mining and processing of metal-bearing ores has resulted in contamination issues where waste materials from abandoned mines remain in piles of untreated and unconsolidated material, posing the potential for waterborne and airborne transport of toxic elements. This study presents a systematic method of particle size separation, mass distribution, and bulk chemical analysis for mine tailings and adjacent background soil samples from the Rand historic mining district, California, in order to assess particle size distribution and related trends in metal(loid) concentration as a function of particle size. Mine tailings produced through stamp milling and leaching processes were found to have both a narrower and finer particle size distribution than background samples, with significant fractions of particles available in a size range (???250 ??m) that could be incidentally ingested. In both tailings and background samples, the majority of trace metal(loid)s display an inverse relationship between concentration and particle size, resulting in higher proportions of As, Cr, Cu, Pb and Zn in finer-sized fractions which are more susceptible to both water- and wind-borne transport as well as ingestion and/or inhalation. Established regulatory screening levels for such elements may, therefore, significantly underestimate potential exposure risk if relying solely on bulk sample concentrations to guide remediation decisions. Correlations in elemental concentration trends (such as between As and Fe) indicate relationships between elements that may be relevant to their chemical speciation. ?? 2011 Elsevier Ltd.

  1. Topological density-wave states in a particle-hole symmetric Weyl metal

    Science.gov (United States)

    Wang, Yuxuan; Ye, Peng

    2016-08-01

    We study the instabilities of a particle-hole symmetric Weyl metal with both electron and hole Fermi surfaces (FSs) around the Weyl points. For a repulsive interaction we find that the leading instability is towards a longitudinal spin-density-wave (SDWz) order. Besides, there exist three degenerate subleading instabilities: a charge-density-wave (CDW) instability, and two transverse spin-density-wave (SDWx ,y) instabilities. For an attractive interaction the leading instabilities are towards two pair-density-wave (PDW) orders which pair the two FSs separately. Both the PDW and SDWz order parameters fully gap out the FSs, while the CDW and SDWx ,y ones leave line nodes on both FSs. For the SDWz and the PDW states, the surface Fermi arc in the metallic state evolves to a chiral Fermi line which passes the projection of the Weyl points and traverses the full momentum space. For the CDW state, the line node projects to a "drumhead" band localized on the surface, which can lead to a topological charge polarization. We verify the surface states by computing the angular-resolved photoemission spectroscopy data.

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

    Science.gov (United States)

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

    2017-05-13

    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%.

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

    Science.gov (United States)

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

    2017-01-01

    Fine (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.

  4. Characterization of compositional modifications in metal-organic frameworks using carbon and alpha particle microbeams

    Science.gov (United States)

    Paneta, V.; Fluch, U.; Petersson, P.; Ott, S.; Primetzhofer, D.

    2017-08-01

    Zirconium-oxide based metal-organic frameworks (MOFs) were grown on p-type Si wafers. A modified linker molecule containing iodine was introduced by post synthetic exchange (PSE). Samples have been studied using Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) techniques, employing the 5 MV 15SDH-2 Pelletron Tandem accelerator at the Ångström laboratory. The degree of post synthetic uptake of the iodine-containing linker has been investigated with both a broad beam and a focused beam of carbon and alpha particles targeting different kind of MOF crystals which were of ∼1-10 μm in size, depending on the linker used. Iodine concentrations in MOF crystallites were also measured by Nuclear Magnetic Resonance Spectroscopy (NMR) and are compared to the RBS results. In parallel to the ion beam studies, samples were investigated by Scanning Electron Microscopy (SEM) to quantify possible crystallite clustering, develop optimum sample preparation routines and to characterize the potential ion beam induced sample damage and its dependence on different parameters. Based on these results the reliability and accuracy of ion beam data is assessed.

  5. Sources and the distribution of heavy metals in the particle size of soil polluted by gold mining upstream of Miyun Reservoir, Beijing: implications for assessing the potential risks.

    Science.gov (United States)

    Li, Qian; Ji, Hongbing; Qin, Fei; Tang, Lei; Guo, Xinyue; Feng, Jinguo

    2014-10-01

    Mining has been carried out upstream of Miyun Reservoir, Beijing, for several decades, and has caused metal emissions to the environment, threatening human health. We conducted a soil survey to assess metal contamination in this area and to determine distribution of heavy metals in the particle size. We attempted to determine the possible sources of the metals and the significance of metals in the fine particle fractions to soil risk assessments. Thirty-four soil samples were collected, and eight samples were partitioned into seven size fractions. Most of the metal concentrations in the soils were higher than the background levels in Beijing, and the metal concentrations and total organic matter (TOC) contents generally increased as the particle size decreased. Each metal except Hg significantly positively correlated with the TOC. The metals in the coarse-grained soils were mainly derived from parent materials, but the metals in the fine fractions were mostly anthropogenic. Statistical analyses showed that there were three metal sources: Cd, Cu, Hg, Pb, and Zn had anthropogenic sources; Co, Cr, Ni, and V had mixed anthropogenic and natural sources; and As and Be had natural sources. The trace metals were primarily in the clay and fine silt fractions, and they might pose health risks through the inhalation of resuspended soil particles (PM10 and PM2.5). The elevated accumulation factors, enrichment factors, and ecological risk indices for the metals in the fine fractions suggest that risk assessments should be based on the fine particle size.

  6. Correlating metal poisoning with zeolite deactivation in an individual catalyst particle by chemical and phase sensitive X-ray microscopy

    NARCIS (Netherlands)

    Ruiz-Martinez, J.; Beale, A.M.|info:eu-repo/dai/nl/325802068; Deka, U.|info:eu-repo/dai/nl/325811202; O'Brien, M.G.|info:eu-repo/dai/nl/314003738; Quinn, P.D.; Mosselmans, J.F.W.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2013-01-01

    Fluid catalytic cracking (FCC) is the main conversion process used in oil refineries. An X-ray microscopy method is used to show that metal poisoning and related structural changes in the zeolite active material lead to a non-uniform core–shell deactivation of FCC catalyst particles. The study links

  7. Method of manufacturing molded articles from metallic or ceramic powdered particles and binder system suitable for use therein

    NARCIS (Netherlands)

    Vervoort, P.J.; Vetter, R.; Duszczyk, J.

    1995-01-01

    The invention relates to a method of manufacturing molded articles by mixing metallic or ceramic powder particles homogeneously with a binder system, whereafter the mixture is shaped in fluid condition by injection molding, the molding obtained is treated with an aqueous liquid in order to wash out

  8. X-ray Fluorescence Tomography of Aged Fluid-Catalytic-Cracking Catalyst Particles Reveals Insight into Metal Deposition Processes

    NARCIS (Netherlands)

    Kalirai, Samanbir; Boesenberg, Ulrike; Falkenberg, Gerald; Meirer, Florian; Weckhuysen, Bert M.

    2015-01-01

    Microprobe X-ray fluorescence tomography was used to investigate metal poison deposition in individual, intact and industrially deactivated fluid catalytic cracking (FCC) particles at two differing catalytic life-stages. 3D multi-element imaging, at submicron resolution was achieved by using a

  9. Particles, sweat, and tears: a comparative study on bioaccessibility of ferrochromium alloy and stainless steel particles, the pure metals and their metal oxides, in simulated skin and eye contact.

    Science.gov (United States)

    Hedberg, Yolanda; Midander, Klara; Wallinder, Inger Odnevall

    2010-07-01

    Ferrochromium alloys are manufactured in large quantities and placed on the global market for use as master alloys (secondary raw materials), primarily for stainless steel production. Any potential human exposure to ferrochromium alloy particles is related to occupational activities during production and use, with 2 main exposure routes, dermal contact and inhalation and subsequent digestion. Alloy and reference particles exposed in vitro in synthetic biological fluids relevant for these main exposure routes have been investigated in a large research effort combining bioaccessibility; chemical speciation; and material, surface, and particle characteristics. In this paper, data for the dermal exposure route, including skin and eye contact, will be presented and discussed. Bioaccessibility data have been generated for particles of a ferrochromium alloy, stainless steel grade AISI 316L, pure Fe, pure Cr, iron(II,III)oxide, and chromium(III)oxide, upon immersion in artificial sweat (pH 6.5) and artificial tear (pH 8.0) fluids for various time periods. Measured released amounts of Fe, Cr, and Ni are presented in terms of average Fe and Cr release rates and amounts released per amount of particles loaded. The results are discussed in relation to bulk and surface composition of the particles. Additional information, essential to assess the bioavailability of Cr released, was generated by determining its chemical speciation and by providing information on its complexation and oxidation states in both media investigated. The effect of differences in experimental temperature, 30 degrees C and 37 degrees C, on the extent of metal release in artificial sweat is demonstrated. Iron was the preferentially released element in all test media and for all time periods and iron-containing particles investigated. The extent of metal release was highly pH dependent and was also dependent on the medium composition. Released amounts of Cr and Fe were very low (close to the limit of

  10. Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part I: physicochemical properties in patient and simulator studies.

    Science.gov (United States)

    Madl, Amy K; Liong, Monty; Kovochich, Michael; Finley, Brent L; Paustenbach, Dennis J; Oberdörster, Günter

    2015-07-01

    The objective of Part I of this analysis was to identify the relevant physicochemical characteristics of wear particles from cobalt-chromium alloy (CoCr) metal-on-metal (MoM) hip implant patients and simulator systems. For well-functioning MoM hip implants, the volumetric wear rate is low (<1mm(3) per million cycles or per year) and the majority of the wear debris is composed of oxidized Cr nanoparticles (<100nm) with minimal or no Co content. For implants with surgical malpositioning, the volumetric wear rate is as high as 100mm(3) per million cycles or per year and the size distribution of wear debris can be skewed to larger sizes (up to 1000nm) and contain higher concentrations of Co. In order to obtain data suitable for a risk assessment of wear debris in MoM hip implant patients, future studies need to focus on particle characteristics relevant to those generated in patients or in properly conducted simulator studies. Metallic implants are very common in the field of orthopedics. Nonetheless, concerns have been raised about the implications of nano-sized particles generated from the wear of these implants. In this two-part review, the authors first attempted to identify and critically evaluate the relevant physicochemical characteristics of CoCr wear particles from hip implant patients and simulator systems. Then they evaluated in vitro and animal toxicology studies with respect to the physicochemistry and dose-relevance to metal-on-metal implant patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Novel and non-traditional use of stable isotope tracers to study metal bioavailability from natural particles

    Science.gov (United States)

    Croteau, Marie-Noële; Cain, Daniel J.; Fuller, Christopher C.

    2013-01-01

    We devised a novel tracing approach that involves enriching test organisms with a stable metal isotope of low natural abundance prior to characterizing metal bioavailability from natural inorganic particles. In addition to circumventing uncertainties associated with labeling natural particles and distinguishing background metals, the proposed "reverse labeling" technique overcomes many drawbacks inherent to using radioisotope tracers. Specifically, we chronically exposed freshwater snails (Lymnaea stagnalis) to synthetic water spiked with Cu that was 99.4% 65Cu to increase the relative abundance of 65Cu in the snail’s tissues from 32% to >80%. The isotopically enriched snails were then exposed to benthic algae mixed with Cu-bearing Fe–Al particles collected from the Animas River (Colorado), an acid mine drainage impacted river. We used 63Cu to trace Cu uptake from the natural particles and inferred their bioavailability from calculation of Cu assimilation into tissues. Cu assimilation from these particles was 44%, indicating that 44% of the particulate Cu was absorbed by the invertebrate. This demonstrates that inorganic particulate Cu can be bioavailable. The reverse labeling approach shows great potential in various scientific areas such as environmental contamination and nutrition for addressing questions involving uptake of an element that naturally has multiple isotopes.

  12. Particle size studies to reveal crystallization mechanisms of the metal organic framework HKUST-1 during sonochemical synthesis.

    Science.gov (United States)

    Armstrong, Mitchell R; Senthilnathan, Sethuraman; Balzer, Christopher J; Shan, Bohan; Chen, Liang; Mu, Bin

    2017-01-01

    Systematic studies of key operating parameters for the sonochemical synthesis of the metal organic framework (MOF) HKUST-1(also called CuBTC) were performed including reaction time, reactor volume, sonication amplitude, sonication tip size, solvent composition, and reactant concentrations analyzed through SEM particle size analysis. Trends in the particle size and size distributions show reproducible control of average particle sizes between 1 and 4μm. These results along with complementary studies in sonofragmentation and temperature control were conducted to compare these results to kinetic crystal growth models found in literature to develop a plausible hypothetical mechanism for ultrasound-assisted growth of metal-organic-frameworks composed of a competitive mechanism including constructive solid-on-solid (SOS) crystal growth and a deconstructive sonofragmentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Cluster model of amorphized particles formation by plasma spraying of metallic powder

    Science.gov (United States)

    Barakhtin, Boris K.; Nesterova, E. V.

    1999-05-01

    Multifunctional coatings from materials with amorphized microcrystalline or nano-phase structure cause a considerable scientific and practical interest. With their help it is to manufacture heat resistant neutralizers of harmful ejections, to produce ecologically clean sources of electric current, to design electromagnetic protective shields and to fabricate a lot of other technical products. The variety of application and a unique complex of operating characteristics (ductility, strength, magnetic and chemical properties) are governed by the basic peculiarity of material in amorphized state - its thermodynamic instability. In comparison with traditional thermodynamically equilibrium metallic alloys, the kinetics of structure changes in amorphous materials is quite different. Thus, it is suggested, that they have peculiar defects (phasonics) which are not typical of materials in crystalline state, they have no translational symmetry and elementary cells. In the process of coatings forming with non-equilibrium structure states can be realized in them, which are characterized by a fluctuation type of origin, entropy export, appearance of space or temporary symmetry uncertainty of the transition direction 'order $ARLR disorder' in bifurcation points. The aforesaid explains a great scientific (not only practical) interest in the structure study of disordered medium. Functional coatings with amorphized, nano- and microcrystalline structure components formed on copper substrate by plasma spraying of dispersed (to 50 mcm) Ni-Al powder. According to the constitutional diagram it was expected to obtain a mixture from equilibrium intermetallide phases NiAl3 + Ni2Al3. The experimental results and investigations performed by X-ray structure, X-ray spectrum and electron microscopy techniques have shown it is possible to obtain phases of variable composition (Ni)m(Al)n with Ni content from 25 to 75 vol.%, including NiAl. It turned out that in the process of spraying the

  14. Partitioning characteristics and particle size distributions of heavy metals in the O{sub 2}/RFG waste incineration system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jyh-Cherng, E-mail: jcchen@sunrise.hk.edu.tw [Department of Safety, Health and Environmental Engineering, HungKuang University, No. 34, Chung-Chie Rd., Shalu, Taichung County 43302, Taiwan (China); Huang, Jian-Sheng [Department of Safety, Health and Environmental Engineering, HungKuang University, No. 34, Chung-Chie Rd., Shalu, Taichung County 43302, Taiwan (China)

    2009-12-30

    This study applies the oxygen/recycled flue gas (O{sub 2}/RFG) combustion technology for waste incineration and investigates the effects of different RFG rates on the concentrations of gas pollutants as well as the partitioning characteristics and particle size distributions of five heavy metals (Cr, Cu, Pb, Zn, and Cd). Experimental results show that the combustion efficiency can be improved and the concentration of CO{sub 2} is increased by appropriately controlling the RFG rate in the O{sub 2}/RFG incineration system. The partitioning characteristics and size distributions of heavy metals in O{sub 2}/RFG combustion system are different from those in general air combustion system. Under O{sub 2}/RFG combustion system, the partitioning percentages of heavy metals in sand bed, bottom ash, and collected ash are increased. The particle size distributions of heavy metals display the triple-peak curves. As the RFG rate rises, the concentrations of volatile heavy metals are increased in small-size (<1 {mu}m) fly ash, decreased in medium-size (1-10 {mu}m) fly ash and increased in large-size (>10 {mu}m) fly ash. These phenomena will benefit to increase the overall control efficiency of heavy metals in the incineration system.

  15. Combustion efficiency and pyrochemical properties of micron-sized metal particles as the components of modified double-base propellant

    Science.gov (United States)

    Wu, Xiong-Gang; Yan, Qi-Long; Guo, Xin; Qi, Xiao-Fei; Li, Xiao-Jiang; Wang, Ke-Qiang

    2011-04-01

    The combustion efficiency of metallized propellants are investigated and compared to the corresponding blank propellant in order to evaluate the actual effect of the metals in solid rocket applications. The image analysis coupled with energy dispersive spectrometry (EDS) analysis on a scanning electron microscope (SEM) and quantitative X-ray diffraction analysis were applied to the characterization of the original metal particles such as aluminum (Al), magnesium (Mg), boron (B), nickel (Ni), and Mg-Al alloy (Mg/Al) and their condensed combustion products. Under the explored operating conditions, the results confirm that the metallized propellants show heterogeneous diffusing flame, with significant change in pressure sensitivity, and larger aggregation/agglomeration phenomena in combustion products than that of the blank propellant. Besides, the chemical reactions in condensed phase and gas phase which control the burning process and combustion efficiency of the double-base propellant containing different metal particles were systematically investigated and descriptions of the detailed reaction mechanisms from solid phase to liquid phase or to gas phase are also included. It was indicated that the combustion efficiency is favored by the activity and melting points of the metals.

  16. The erosion performance of particle reinforced metal matrix composite coatings produced by co-deposition cold gas dynamic spraying

    Science.gov (United States)

    Peat, Tom; Galloway, Alexander; Toumpis, Athanasios; McNutt, Philip; Iqbal, Naveed

    2017-02-01

    This work reports on the erosion performance of three particle reinforced metal matrix composite coatings, co-deposited with an aluminium binder via cold-gas dynamic spraying. The deposition of ceramic particles is difficult to achieve with typical cold spray techniques due to the absence of particle deformation. This issue has been overcome in the present study by simultaneously spraying the reinforcing particles with a ductile metallic binder which has led to an increased level of ceramic/cermet particles deposited on the substrate with thick (>400 μm) coatings produced. The aim of this investigation was to evaluate the erosion performance of the co-deposited coatings within a slurry environment. The study also incorporated standard metallographic characterisation techniques to evaluate the distribution of reinforcing particles within the aluminium matrix. All coatings exhibited poorer erosion performance than the uncoated material, both in terms of volume loss and mass loss. The Al2O3 reinforced coating sustained the greatest amount of damage following exposure to the slurry and recorded the greatest volume loss (approx. 2.8 mm3) out of all of the examined coatings. Despite the poor erosion performance, the WC-CoCr reinforced coating demonstrated a considerable hardness increase over the as-received AA5083 (approx. 400%) and also exhibited the smallest free space length between adjacent particles. The findings of this study reveal that the removal of the AA5083 matrix by the impinging silicon carbide particles acts as the primary wear mechanism leading to the degradation of the coating. Analysis of the wear scar has demonstrated that the damage to the soft matrix alloy takes the form of ploughing and scoring which subsequently exposes carbide/oxide particles to the impinging slurry.

  17. PRODUCTION OF METAL CHEMICAL WELDING ADDITIVE WITH NANODISPERSED PARTICLES OF TITANIUM DIOXIDE

    Directory of Open Access Journals (Sweden)

    BOLDYREV Alexander Mikhaylovich

    2013-12-01

    Full Text Available When welding bridge structures automatic welding under a gumboil layer with metal chemical additive (MCA is widely applied in the modern bridge building. MCA consists of a chopped welding wire (granulated material, which is powdered by modifying chemical additive of titanium dioxide (TiO₂ in the cylindrical mixer «drunk cask». Chemical composition of all welding materials including welding wire, gumboil, electrodes, are strictly normalized and controlled. However, the existing technology of producing MCA doesn’t allow precise controlling of its structure under working conditions and that causes an impact on the stability of welded connections properties. Therefore the aim of this work is to develop a technology to produce stable MCA structure. The paper compares the existing and proposed manufacturing techniques of the metal chemical additive (MCA which is applied in automatic welding of butt connections for bridge structures. It is shown that production of MCA in a high-energy planetary mill provides more stable structure of the additive introduced into a welded joint. The granulometric analysis of the powder TiO₂ showed that when processing MCA in a planetary mill TiO₂ particles are crashed to nanodimensional order. This process is accompanied by crushing of granulated material too. The proposed method for production of MCA in a planetary mill provides stronger cohesion of dioxide with the granulate surface and, as a consequence, more stable MCA chemical structure. Application of MCA which has been mechanical intensified in a planetary mill, increases stability of mechanical properties, if compare with applied technology, in single-order by breaking point and almost twice by impact viscosity.

  18. Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    House, Stephen D., E-mail: sdh46@pitt.edu [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Bonifacio, Cecile S.; Grieshaber, Ross V.; Li, Long; Zhang, Zhongfan [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Ciston, Jim [National Center of Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Stach, Eric A. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States); Yang, Judith C. [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2016-10-15

    High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures. - Highlights: • The impact of supports on imaging nanoparticle lattice structure is quantified. • Visualization probabilities given particle size and support thickness are estimated. • Aberration-correction provided limited benefit

  19. Imaging Flow Cytometry Assays for Quantifying Pigment Grade Titanium Dioxide Particle Internalisation and Interactions with Immune Cells in Whole Blood.

    OpenAIRE

    Hewitt, Rachel Elaine; Vis, B.; Pele, LC; Rodrigues Faria, Nuno Jorge; Powell, Jonathan Joseph

    2017-01-01

    Pigment grade titanium dioxide is composed of sub-micron sized particles, including a nano fraction, and is widely utilised in food, cosmetic, pharmaceutical and biomedical industries. Oral exposure to pigment grade titanium dioxide results in at least some material entering the circulation in humans, although subsequent interactions with blood immune cells are unknown. Pigment grade titanium dioxide is employed for its strong light scattering properties and this work exploited that attribut...

  20. Annual trends in occurrence of submicron particles in ambient air and health risk posed by particle bound metals.

    Science.gov (United States)

    Izhar, Saifi; Goel, Anubha; Chakraborty, Abhishek; Gupta, Tarun

    2016-03-01

    Risk analysis is highly important in toxicology and public health studies. Health risk related to exposure to toxic metals of PM1 was assessed. Concentrations of 13 heavy metals, adsorbed to submicron particulate matter PM1 were experimentally examined but only 12 metals were found at detectable levels inside IIT Kanpur campus in 2008-2009 for all months excluding June and October. A total of 90 samples collected for 8 h sampling time by a single stage round nozzle, grease impaction substrate based impactor type PM1 sampler were analysed by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry). Results showed daily average PM1 concentration is 102.46 ± 35.9 μg/m(3) and metal concentration followed the trend: Ca > Fe > Mg > Zn > Pb > Cu > Cr > Ni > Se > Cd > V > As. Contamination level assessment using geo-accumulation index showed Ca, Fe and Mg exhibited non contamination whereas metals like Cr, Zn, As, Cd, Pb, Se, Ni and Cu exhibited ranges from moderate to extreme contamination. Ingestion is found to be the major exposure pathway for heavy metals. Non-carcinogenic health risk assessment for Pb, Cd and Cr (HI > 1) signified strong chances of adverse impact on children whereas adults are well under safe limit. Cancer Risk for adults and children followed the same decreasing order, Cr(VI)>Cd > Ni > As > Pb. It was found to be higher than permissible limits (10(-6)) for adults and children both. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. A comparison of two methods for metallizing fly-ash cenosphere particles: electroless plating and magnetron sputtering

    Science.gov (United States)

    Cai, Chujiang; Yu, Xiaozheng; Shen, Zhigang; Xing, Yushan

    2007-10-01

    A dense and uniform metal layer was completely coated on the surface of fly-ash cenosphere particles by either electroless plating or magnetron sputtering technique. The surface morphology and characteristics of the electroless and sputtered metal coatings have been compared and investigated by various characterization methods, including scanning electron microscopy, energy dispersion x-ray spectrum, x-ray photoelectron spectroscopy, optical microscopy and atomic force microscopy. The results indicate that the electroless plating process has a faster deposition rate as compared with the sputtering process, and the metal coating fabricated by electroless plating is rough as compared with the metal coating fabricated by magnetron sputtering. The Cu-coated fine cenospheres could be fabricated by the electroless plating technique.

  2. A comparison of two methods for metallizing fly-ash cenosphere particles: electroless plating and magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Cai Chujiang; Yu Xiaozheng; Shen Zhigang; Xing Yushan [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)

    2007-10-07

    A dense and uniform metal layer was completely coated on the surface of fly-ash cenosphere particles by either electroless plating or magnetron sputtering technique. The surface morphology and characteristics of the electroless and sputtered metal coatings have been compared and investigated by various characterization methods, including scanning electron microscopy, energy dispersion x-ray spectrum, x-ray photoelectron spectroscopy, optical microscopy and atomic force microscopy. The results indicate that the electroless plating process has a faster deposition rate as compared with the sputtering process, and the metal coating fabricated by electroless plating is rough as compared with the metal coating fabricated by magnetron sputtering. The Cu-coated fine cenospheres could be fabricated by the electroless plating technique.

  3. Enhanced Mechanical Properties of MgZnCa Bulk Metallic Glass Composites with Ti-Particle Dispersion

    Directory of Open Access Journals (Sweden)

    Pei Chun Wong

    2016-05-01

    Full Text Available Rod samples of Mg60Zn35Ca5 bulk metallic glass composites (BMGCs dispersed with Ti particles have been successfully fabricated via injection casting. The glass forming ability (GFA and the mechanical properties of these Mg-based BMGCs have been systematically investigated as a function of the volume fraction (Vf of Ti particles. The results showed that the compressive ductility increased with Vf. The mechanical performance of these BMGCs, with up to 5.4% compressive failure strain and 1187 MPa fracture strength at room temperature, can be obtained for the Mg-based BMGCs with 50 vol % Ti particles, suggesting that these dispersed Ti particles can absorb the energy of the crack propagations and can induce branches of the primary shear band into multiple secondary shear bands. It follows that further propagation of the shear band is blocked, enhancing the overall plasticity.

  4. Feasibility of asymmetric flow field-flow fractionation coupled to ICP-MS for the characterization of wear metal particles and metalloproteins in biofluids from hip replacement patients

    DEFF Research Database (Denmark)

    Löschner, Katrin; Harrington, Chris F.; Kearney, Jacque-Lucca

    2015-01-01

    Hip replacements are used to improve the quality of life of people with orthopaedic conditions, but the use of metal-on-metal (MoM) arthroplasty has led to poor outcomes for some patients. These problems are related to the generation of micro- to nanosized metal wear particles containing Cr, Co o...

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

    Science.gov (United States)

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

    2017-01-01

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

  6. Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes.

    Science.gov (United States)

    Yurekli, Yilmaz

    2016-05-15

    In this study, the adsorption and the filtration processes were coupled by a zeolite nanoparticle impregnated polysulfone (PSf) membrane which was used to remove the lead and the nickel cations from synthetically prepared solutions. The results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis indicated that the synthesized zeolite nanoparticles, using conventional hydrothermal method, produced a pure NaX with ultrafine and uniform particles. The performance of the hybrid membrane was determined under dynamic conditions. The results also revealed that the sorption capacity as well as the water hydraulic permeability of the membranes could both be improved by simply tuning the membrane fabricating conditions such as evaporation period of the casting film and NaX loading. The maximum sorption capacity of the hybrid membrane for the lead and nickel ions was measured as 682 and 122 mg/g respectively at the end of 60 min of filtration, under 1 bar of transmembrane pressure. The coupling process suggested that the membrane architecture could be efficiently used for treating metal solutions with low concentrations and transmembrane pressures. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Influence of particle bombardment on microstructure and internal stresses of refractory metal suicides on silicon

    Science.gov (United States)

    Hardtke, Ch.; Schilling, W.; Ullmaier, H.

    1991-07-01

    First results on microstructural changes and stress relaxation in thin refractory metal suicide films (TaSi 2 and MoSi 2) caused by particle bombardment are reported. The polycrystalline films had initial tensile stresses of some 10 9 Pa. Exposed to irradiation with Ge ions of 400 keV, both suicides showed a similar stress relaxation behaviour as a function of dose. During room-temperature implantation the initial tensile stress rapidly decreased and turned into compressive stress. Continuous irradiation partly relaxed the compressive stress and resulted in a saturation value of some -10 8 Pa. With increasing implantation temperature, the buildup of compressive stress gradually vanished, leaving only the initial decrease of tensile stress which finally approached zero. Based on microstructural investigations (TEM and X-ray diffraction) it is proposed to explain this behaviour by the combined action of two processes: relaxation of tensile stress by a volume increase due to irradiation-induced amorphization, and Frenkel defect production and relaxation of compressive stress by irradiation-induced densification of amorphous regions and/or Frenkel defect elimination.

  8. Ejecta from shocked metals: Comparative simulations using molecular dynamics and smoothed particle hydrodynamics

    Science.gov (United States)

    Dyachkov, Sergey; Parshikov, Anatoly; Zhakhovsky, Vasily

    2017-01-01

    Experimental methods of observation of early stage of shock-induced ejecta from metal surface with micrometer-sized perturbations are still limited in terms of following a complete sequence of processes having microscale dimensions and nanoscale times. To get an insight into micro-jet formation the ejecting from tin and copper samples is simulated in detail by smoothed particle hydrodynamics (SPH) and molecular dynamics (MD) methods. Such a comparative study shows, with some exception, a good similarity between material flows in nanometer- and micrometer-sized samples. We demonstrate that the jet velocity profiles and mass distributions obtained by both methods are similar, even for a MD sample with the linear size of 100 nm. It is shown that the bigger MD sample is simulated, the better agreement with SPH results is achieved for spike velocities of liquid jets due to decrease of surface tension effect. The calculated ejecta masses do nonetheless agree well for all sizes of interest. Material strength effect is also discussed in our comparative MD and SPH study. At relatively weak shock loading the plastic flow and jet formation is strongly arrested in MD sample due to a higher yield strength of solid at very high strain rates evolving on MD scale. In such conditions MD results are not scaled well to SPH results obtained at several order less strain rates.

  9. METALS DISTRIBUTION AND PARTICLE SIZE ANALYSIS IN WATER AND SEDIMENT OF THE DJETINJA RIVER AND DRAGIĆA SPRING (SERBIA

    Directory of Open Access Journals (Sweden)

    JELENA KIURSKI

    2010-12-01

    Full Text Available This paper reports the results on total metal concentration (Al, Fe, Cr, Cu, Ni and Zn in water and sediment of the Djetinja river basin in the area of western Serbia. Samples were collected in spring season. Based on the comparison of the concentrations of all analyzed metals it is possible to differentiate two zo¬nes: zone I (sampling sites 1-4, affected by the discharge of the Dragića spring, and zone II (sites 5-8, affected by the confluence of the Dragića spring with the Djetinja river. The analysis of suspended solid particle size in water as well as in sediment samples was performed in size range 0.02-2000 m and a posi¬tive corelation was found with the concentration of aluminium, zinc, iron and nickel in water samples. The study of particle size and metals distribution through the river basin of the Djetinja was a useful tool for getting information about the distribution degree of the polluting agents, and their possible evolution growth and pollution sources. The research of metals distribution and particle size analysis in water and sediment of the Djetinja river and Dragića spring (Serbia was conducted for the first time.

  10. Detection of the multiple spallation parameters and the internal structure of a particle cloud during shock-wave loading of a metal

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, A. V., E-mail: fedorovsarov@mail.ru; Mikhailov, A. L.; Finyushin, S. A.; Kalashnikov, D. A.; Chudakov, E. A.; Butusov, E. I.; Gnutov, I. S. [Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics (VNIIEF) (Russian Federation)

    2016-04-15

    The results of experiments on studying spallation and the ejection of particles from the surfaces of copper and lead samples are presented. A laser interferometry method is used to detect the particle cloud velocity and the multiple spallation parameters. Angular detectors are used to detect the depth profile of the particle cloud velocity dispersion and the structure of metal spallation.

  11. Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Gon Corradini, Patricia; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma, E-mail: jperez@iqsc.usp.br [Instituto de Quimica de Sao Carlos, USP (Brazil); Antolini, Ermete [Scuola di Scienza dei Materiali (Italy)

    2012-09-15

    The effect of the relationship between particle size (d), inter-particle distance (x{sub i}), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x{sub i}/d (>5) values, was evaluated. It was found that for y < 30 wt%, the optimum values of both d and x{sub i}/d can be always obtained. For y {>=} 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y < 30 wt% is concomitant to a decrease of the effective catalyst surface area due to an increase of d and/or a decrease of x{sub i}/d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x{sub i}/d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x{sub i}/d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

  12. Spatial variations in selected metal contents and particle size distribution in an urban and rural atmosphere of Islamabad, Pakistan.

    Science.gov (United States)

    Shah, Munir H; Shaheen, N; Jaffar, M; Khalique, A; Tariq, Saadia R; Manzoor, S

    2006-01-01

    Spatial variations in total suspended particulate matter (TSP) were investigated for distribution of metals and particle size fractions in the urban and rural atmosphere of Islamabad, Pakistan. The metals Na, K, Fe, Mn, Pb, Cd, Cr, Zn, Ni and Co, and the particle fractions 100 microm were included in the study. TSP samples were trapped on glass fibre filters using high volume samplers and quantification of metals was done using Atomic Absorption Spectrometry employing HNO(3) based wet digestion. At the urban site, Na was dominant at 2.384 microg/m(3) followed by K, Fe and Zn with 0.778, 0.667 and 0.567 microg/m(3) as mean concentrations, respectively. The metal levels for the rural site ranged from 0.002 microg/m(3) for Cd to 1.077 microg/m(3) for Na. However, compared with the urban site, mean Pb concentration showed an almost two-fold enhancement, i.e., 0.163 Vs. 0.327 microg/m(3). Metals and particle size source identification was done using Principal Component Analysis and Cluster Analysis. Five sources were traced out for the urban site: industrial, soil, automobile emissions, metallurgical industries and excavation activities. For the rural site, four sources were recorded: agricultural, automotive emissions, excavation activities and metallurgical units. Collectively, for both the sites, PM(10-100) emerged as a major contributor to TSP, followed by PM(2.5-10), PM(100) in that order. The metals showed in general positive relationship with fine particulate fractions (PM(2.5-10), PM(100)). Comparison with the corresponding data from various Asian sites revealed that the levels of Na, K, Fe, Mn, Co and Ni for the present study were lower than those reported for grossly polluted cities of the world.

  13. [Distributions and pollution status of heavy metals in the suspended particles of the estuaries and coastal area of eastern Hainan].

    Science.gov (United States)

    Xin, Cheng-Lin; Ren, Jing-Ling; Zhang, Gui-Ling; Shao, Ya-Ping; Zhang, Guo-Ling; Liu, Su-Mei

    2013-04-01

    The distributions and pollution status of heavy metals in the suspended particles were investigated in the Wanquan and Wenchang/Wenjiao estuaries and the coastal area of eastern Hainan in July 2008. The concentrations of metal elements (Al, Fe, Mn, Cr, Cu, Ni, V, Zn) were determined by ICP-AES after microwave digestion. Multivariate statistical methods (e. g. correlation analysis and principal factor analysis) were used to discuss the major factors controlling the variability of heavy metal concentrations and the pollution status in those areas. There was an obvious variability in particulate metal concentrations from upstream to estuary of both rivers. The concentrations first increased with increasing salinity and then decreased with further increase of the salinity; the concentrations were slightly higher at the coastal area in the east. The variability of particulate metal concentrations reduced significantly after the normalization by Al, indicating the effects of grain size. Enrichment factor calculation results showed that there was heavy metal pollution (especially Cu, Ni) in the Wenchang/Wenjiao River and estuary, while the situation in Wanquan River remained at pristine level. Concentrations of particulate metals in the study area were mainly controlled by source geology and provenance, as well as contamination from the discharge of waste water and biological activity.

  14. Kinetic study of phytotoxicity induced by foliar lead uptake for vegetables exposed to fine particles and implications for sustainable urban agriculture.

    Science.gov (United States)

    Xiong, TianTian; Austruy, Annabelle; Pierart, Antoine; Shahid, Muhammad; Schreck, Eva; Mombo, Stéphane; Dumat, Camille

    2016-08-01

    At the global scale, foliar metal transfer occurs for consumed vegetables cultivated in numerous urban or industrial areas with a polluted atmosphere. However, the kinetics of metal uptake, translocation and involved phytotoxicity was never jointly studied with vegetables exposed to micronic and sub-micronic particles (PM). Different leafy vegetables (lettuces and cabbages) cultivated in RHIZOtest® devices were, therefore, exposed in a greenhouse for 5, 10 and 15days to various PbO PM doses. The kinetics of transfer and phytotoxicity was assessed in relation to lead concentration and exposure duration. A significant Pb accumulation in leaves (up to 7392mg/kg dry weight (DW) in lettuce) with translocation to roots was observed. Lead foliar exposure resulted in significant phytotoxicity, lipid composition change, a decrease of plant shoot growth (up to 68.2% in lettuce) and net photosynthesis (up to 58% in lettuce). The phytotoxicity results indicated plant adaptation to Pb and a higher sensitivity of lettuce in comparison with cabbage. Air quality needs, therefore, to be considered for the health and quality of vegetables grown in polluted areas, such as certain megacities (in China, Pakistan, Europe, etc.) and furthermore, to assess the health risks associated with their consumption. Copyright © 2016. Published by Elsevier B.V.

  15. Metal-like conductivity exhibited by triboelectrically deposited polyaniline (emeraldine base) particles on microtextured SiC surfaces

    Science.gov (United States)

    Bayer, I. S.; Caramia, V.; Biswas, A.; Cingolani, R.; Athanassiou, A.

    2012-05-01

    We demonstrate a simple and rapid way to deposit layers of polyaniline (emeraldine base) particles on flexible microtextured silicon carbide surfaces by contact charging them using a smooth dielectric rubber. Wetting of the layers by trifluoroacetic acid creates conductive, continuous polymeric films after drying. Pre-functionalization of the textured surfaces with anionic surfactants prevents particle coagulation during contact charging and decreases sheet resistance to metal-like levels (˜60 Ω/□). Conductivity of the films can be tuned by controlling the rate of acid evaporation. Conductive films are highly stable under ambient conditions and show no hysteresis when biased with zero delay-time.

  16. A study of the nature of solid particle impact and shape on the erosion morphology of ductile metals

    Science.gov (United States)

    Rao, P. V.; Young, S. G.; Buckley, D. H.

    1982-01-01

    Impulsive versus steady jet impingement of spherical glass bead particles on metal surfaces was studied using a gas gun facility and a commercial sand blasting apparatus. Crushed glass particles were also used in the sand blasting apparatus as well as glass beads. Comparisons of the different types of erosion patterns were made. Scanning electron microscopy, surface profilometry and energy dispersive X-ray spectroscopy analysis were used to characterize erosion patterns. The nature of the wear can be divided into cutting and deformation, each with its own characteristic features. Surface chemistry analysis indicates the possibility of complex chemical and/or mechanical interactions between erodants and target materials.

  17. Coupling of Acoustic Cavitation with Dem-Based Particle Solvers for Modeling De-agglomeration of Particle Clusters in Liquid Metals

    Science.gov (United States)

    Manoylov, Anton; Lebon, Bruno; Djambazov, Georgi; Pericleous, Koulis

    2017-11-01

    The aerospace and automotive industries are seeking advanced materials with low weight yet high strength and durability. Aluminum and magnesium-based metal matrix composites with ceramic micro- and nano-reinforcements promise the desirable properties. However, larger surface-area-to-volume ratio in micro- and especially nanoparticles gives rise to van der Waals and adhesion forces that cause the particles to agglomerate in clusters. Such clusters lead to adverse effects on final properties, no longer acting as dislocation anchors but instead becoming defects. Also, agglomeration causes the particle distribution to become uneven, leading to inconsistent properties. To break up clusters, ultrasonic processing may be used via an immersed sonotrode, or alternatively via electromagnetic vibration. This paper combines a fundamental study of acoustic cavitation in liquid aluminum with a study of the interaction forces causing particles to agglomerate, as well as mechanisms of cluster breakup. A non-linear acoustic cavitation model utilizing pressure waves produced by an immersed horn is presented, and then applied to cavitation in liquid aluminum. Physical quantities related to fluid flow and quantities specific to the cavitation solver are passed to a discrete element method particles model. The coupled system is then used for a detailed study of clusters' breakup by cavitation.

  18. Sum-frequency generation spectroscopy on metals, oxides, and oxide-supported metal particles; Summenfrequenzerzeugungsspektroskopie an Metallen, Oxiden und oxidgetraegerten Metallpartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Aumer, Andreas

    2010-06-21

    This thesis focuses on 4 different model systems of surface science. The experimental techniques used for the measurements include sum frequency generation (SFG), thermal desorption spectroscopy (TDS), low energy electron diffraction (LEED), Auger electron spectroscopy (AES), infrared adsorption spectrosocopy (IRAS) and scanning tunneling microscopy (STM). By using SFG, measurements could be performed up to a pressure of 50 mbar. The systems under investigation were: CO on Pt(111), water on Ag(001) and on MgO/Ag(001), CO on Au/MgO/Ag(001), and CO on Au-Pd/MgO/Ag(001). The system of CO on Pt(111) exhibits a two peak-pattern under certain pressure and temperature conditions which has not been studied so far. Various experiments helped to elucidate the origin of this distinct behaviour. The measurements of water on Ag(001) and MgO/Ag(001) show that on MgO, water first adsorbs as a monolayer with a following multilayer, whereas on Ag(001) it adsorbs as a multilayer from the beginning. The monolayer can be studied below the multilayer and some resonances can be identified. For the case of Au/MgO/Ag(001), STM shows that the growth mode of Au depends on the thickness of the supporting MgO film, which can not be seen with spectroscopic methods. For mixed Au-Pd particles on MgO/Ag(001) a clear difference in the adsorption behaviour between pure metal particles and mixed particles can be seen, which is explained by an interaction between these metals. Annealing the mixed particles to 600 K leads to a segregation of the metals, where the Au atoms diffuse to the shell and the Pd atoms make up the core. The results of all these measurements are discussed in the light of recent publications. (orig.)

  19. Feasibility of granular bed filtration of an aerosol of ultrafine metallic particles including a pressure drop regeneration system.

    Science.gov (United States)

    Bémer, D; Wingert, L; Morele, Y; Subra, I

    2015-09-01

    A process for filtering an aerosol of ultrafine metallic particles (UFP) has been designed and tested, based on the principle of a multistage granular bed. The filtration system comprised a succession of granular beds of varying thickness composed of glass beads of different diameters. This system allows the pressure drop to be regenerated during filtration ("on-line" mode) using a vibrating probe. Tests monitoring the pressure drop were conducted on a "10-L/min" low airflow rate device and on a "100-m(3)/hr" prototype. Granular bed unclogging is automated on the latter. The cyclic operation and filtration performances are similar to that of filter medium-based industrial dust collectors. Filtration of ultrafine metallic particles generated by different industrial processes such as arc welding, metal cutting, or spraying constitutes a difficult problem due to the high filter clogging properties of these particles and to the high temperatures generally encountered. Granular beds represent an advantageous means of filtering these aerosols with difficult properties.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2001-05-04

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NO{sub x} concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end we shall use an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined.

  1. Influence of MgO particles on Microstructural and Mechanical Behaviour of AA7068 Metal Matrix Composites

    Science.gov (United States)

    Joshua, K. John; Vijay, S. J.; Selvaraj, D. Philip; Ramkumar, P.

    2017-10-01

    Present work deals with the fabrication of AA7068 metal matrix composites reinforced with different weight percentages of MgO (0%, 1%, 2%, and 5%) produced using powder metallurgy route. A low pressure of 318 MPa was applied for compacting the composites and sintered at a temperature of 560°C for one hour. Optical microscopy was done to study the microstructural behavior. Wear test has been conducted for a sliding distance of 3 km with a sliding velocity of 1.2 m/s of load 5N.,7.5N and 10N. Vickers micro hardness test has been conducted and the maximum value of 68 VHN was obtained by adding a weight percentage of 5% MgO particles. The wear resistance has been improved by adding MgO particles in the matrix material. EDAX analysis was done to ensure the presence of MgO particles.

  2. THERMO-MECHANICAL MODELLING OF METAL STRUCTURES SUBJECTED TO HIGH ENERGY PARTICLE BEAM IMPACTS

    CERN Document Server

    Peroni, L; Dallocchio, A

    2011-01-01

    Particle accelerators [Wiedemann 1993] act as microscopes for such a complex research; these large machines accelerate charged elementary particles (electrons, protons or ionized atoms) to high kinetic energies. A high energy particle beam can be brought into collision against a fixed target or against another beam and from this encounter a multitude of short life sub-atomic particles is originated. The higher the energy of the colliding beams and the event rate, the wider the spectrum of the generable sub-atomic particles.

  3. Ozone reaction with clothing and its initiated particle generation in an environmental chamber

    Science.gov (United States)

    Rai, Aakash C.; Guo, Bing; Lin, Chao-Hsin; Zhang, Jianshun; Pei, Jingjing; Chen, Qingyan

    2013-10-01

    Ozone-initiated chemistry in indoor air can produce sub-micron particles, which are potentially harmful for human health. Occupants in indoor spaces constitute potential sites for particle generation through ozone reactions with human skin and clothing. This investigation conducted chamber experiments to examine particle generation from ozone reactions with clothing (a T-shirt) under different indoor conditions. We studied the effect of various factors such as ozone concentration, relative humidity, soiling levels of T-shirt with human skin oils, and air change rate on particle generation. The results showed that ozone reactions with the T-shirt generated sub-micron particles, which were enhanced by the soiling of the T-shirt with human skin oils. In these reactions, a burst of ultrafine particles was observed about one hour after ozone injection, and then the particles grew to larger sizes. The particle generation from the ozone reactions with the soiled T-shirt was significantly affected by the different factors studied and these reactions were identified as another potential source for indoor ultrafine particles.

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

    Directory of Open Access Journals (Sweden)

    Castranova Vincent

    2009-04-01

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

  5. Structural characterizaiton and gas reactions of small metal particles by high-resolution, in-situ TEM and TED

    Science.gov (United States)

    1984-01-01

    The existing in-situ transmission electron microscopy (TEM) facility was improved by adding a separately pumped mini-specimen chamber. The chamber contains wire-evaporation sources for three metals and a specimen heater for moderate substrate temperatures. A sample introduction device was constructed, installed, and tested, facilitating rapid introduction of a specimen into the mini-chamber while maintaining the background pressure in that chamber in the 10(-9) millibar range. Small particles and clusters of Pd, grown by deposition from the vapor phase in an in-situ TEM facility on amorphous and crystalline support films of alumina and on ultra-thin carbon films, were analyzed by conventional high-resolution TEM and image analysis in terms of detectability, number density, and size distribution. The smallest particles that could be detected and counted contained no more than 6 atoms; size determinations could be made for particles 1 nm in diameter. The influence of various oxygen plasma treatments, annealing treatments, and of increasing the substrate temperature during deposition was investigated. The TEM technique was employed to demonstrate that under otherwise identica l conditions the lattice parameter of Pd particles in the 1 to 2 nm size range and supported in random orientation on ex-situ prepared mica films is expanded by some 3% when compared to 5 nm size particles. It is believed that this expansion is neither a small-particle diffraction effect nor due to pseudomorphism, but that it is due to a annealing-induced transformation of the small as-deposited particles with predominantly composite crystal structures into larger particles with true f.c.c. structure and thus inherently smaller lattice parameter.

  6. Progress Towards a Benchtop Energetics Capability (BRIEFING CHARTS)

    National Research Council Canada - National Science Library

    Fajardo, Mario E; Lewis, William K

    2006-01-01

    The incorporation of nanometric (sub-micron size) metal fuel and oxidizer particles into energetic materials is a promising approach to increasing significantly the systems-level performance of munitions...

  7. Characteristics of trace metals in traffic-derived particles in Hsuehshan Tunnel, Taiwan: size distribution, potential source, and fingerprinting metal ratio

    Science.gov (United States)

    Lin, Y.-C.; Tsai, C.-J.; Wu, Y.-C.; Zhang, R.; Chi, K.-H.; Huang, Y.-T.; Lin, S.-H.; Hsu, S.-C.

    2015-04-01

    Traffic emissions are a significant source of airborne particulate matter (PM) in ambient environments. These emissions contain an abundance of toxic metals and thus pose adverse effects on human health. Size-fractionated aerosol samples were collected from May to September 2013 by using micro-orifice uniform deposited impactors (MOUDIs). Sample collection was conducted simultaneously at the inlet and outlet sites of Hsuehshan Tunnel in northern Taiwan, which is the second-longest freeway tunnel (12.9 km) in Asia. This endeavor aims to characterize the chemical constituents and size distributions, as well as fingerprinting ratios of particulate metals emitted by vehicle fleets. A total of 36 metals in size-resolved aerosols were determined through inductively coupled plasma mass spectrometry. Three major groups - namely, tailpipe emissions (Zn, Pb, and V in fine mode), wear debris (Cu, Cd, Fe, Ga, Mn, Mo, Sb, and Sn), and resuspended dust (Ca, Mg, K, and Rb) - of airborne PM metals were categorized on the basis of the results of enrichment factor, correlation matrix, and principal component analysis. Size distributions of wear-originated metals resembled the pattern of crustal elements, which were predominated by super-micron particulates (PM1-10). By contrast, tailpipe exhaust elements such as Zn, Pb, and V were distributed mainly in submicron particles. By employing Cu as a tracer of wear abrasion, several inter-metal ratios - including Fe / Cu (14), Ba / Cu (1.05), Sb / Cu (0.16), Sn / Cu (0.10), and Ga / Cu (0.03) - served as fingerprints for wear debris. However, the data set collected in this work is useful for further studies on traffic emission inventory and human health effects of traffic-related PM.

  8. Mobility of trace metals associated with urban particles exposed to natural waters of various salinities from the Gironde Estuary, France

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Joerg; Blanc, Gerard [Bordeaux Univ., Talence (France). UMR 5805 EPOC; Norra, Stefan [Karlsruhe Univ. (Germany). Inst. of Mineralogy and Geochemistry; Klein, Daniel [Bordeaux Univ., Talence (France). UMR 5805 EPOC; Karlsruhe Univ. (Germany). Inst. of Mineralogy and Geochemistry

    2009-08-15

    extracted by means of concentrated HNO{sub 3}, estuarine freshwaters and waters of two different salinities (S=15 and S=31). Analysis of trace elements was carried out by means of quadrupole inductively coupled plasma-mass spectrometry. Furthermore, single particles from road sediments were characterised with scanning electron microscopy (SEM). Results: SEM analysis clearly showed that some particles contained fairly high concentrations of potentially toxic trace elements. Extractions of materials investigated by varying acidities and salinities documented that the potentially bioavailable fractions extracted by concentrated HNO{sub 3} may cover wide concentration ranges. Natural estuarine waters of various salinities (S=0.5; S=15; S=31) extracted high proportions of Co, Ni, Cu, Zn and Cd from urban particles, especially for high-salinity water (S=31). Extractions with freshwater revealed the lowest concentrations of desorbed trace elements. Particulate Mo, Pb and V showed similar or lower mobility in saline water compared with freshwater, depending on the sample type. Discussion: Trace element mobility in estuarine waters varied according to the type of urban particles and depended on salinity for Co, Ni, Cu, Zn and Cd. This is of high importance for towns located directly at the coast or for cities like Bordeaux, where water courses crossing the agglomerations are connected to saline water masses. Since trace elements desorbed from particles in saline waters may become highly bioavailable, they bear a potential risk for organisms. Comprehensive studies on the behaviour of urban particles in estuarine waters and the related potential environmental impact are still missing. Conclusions: Saline waters mobilise relatively high amounts of Co, Ni, Cu, Zn and Cd from urban particles suggesting considerable metal fluxes from riverine urban systems into coastal waters. Although estimates of trace metal inputs by urban bulk deposition (urban dust) and other types of urban particles

  9. X-ray Fluorescence Tomography of Aged Fluid-Catalytic-Cracking Catalyst Particles Reveals Insight into Metal Deposition Processes.

    Science.gov (United States)

    Kalirai, Sam; Boesenberg, Ulrike; Falkenberg, Gerald; Meirer, Florian; Weckhuysen, Bert M

    2015-11-01

    Microprobe X-ray fluorescence tomography was used to investigate metal poison deposition in individual, intact and industrially deactivated fluid catalytic cracking (FCC) particles at two differing catalytic life-stages. 3 D multi-element imaging, at submicron resolution was achieved by using a large-array Maia fluorescence detector. Our results show that Fe, Ni and Ca have significant concentration at the exterior of the FCC catalyst particle and are highly co-localized. As concentrations increase as a function of catalytic life-stage, the deposition profiles of Fe, Ni, and Ca do not change significantly. V has been shown to penetrate deeper into the particle with increasing catalytic age. Although it has been previously suggested that V is responsible for damaging the zeolite components of FCC particles, no spatial correlation was found for V and La, which was used as a marker for the embedded zeolite domains. This suggests that although V is known to be detrimental to zeolites in FCC particles, a preferential interaction does not exist between the two.

  10. Distribution of metal released from cobalt-chromium alloy orthopaedic wear particles implanted into air pouches in mice.

    Science.gov (United States)

    Afolaranmi, Grace A; Akbar, Moeed; Brewer, James; Grant, M Helen

    2012-06-01

    Metal-on-metal hip replacement implants generate wear debris and release ions both locally and systemically in patients. To investigate dissemination of metal, we determined blood and organ levels of cobalt (Co), chromium (Cr), and molybdenum (Mo) following the implantation of Co-Cr alloy wear debris in mice using skin pouches as a model system. We observed increased metal levels in blood for up to 72 h; the levels of Co were highest and remained elevated for 7 days. Co levels were elevated in all organs studied (liver, kidney, spleen, lung, heart, brain, and testes), with the peak at 48 h; highest levels were measured in liver and kidney (838.9 ± 223.7 ng/g in liver, and 938.8 ± 131.6 ng/g in kidney). Organ Cr levels were considerably lower than Co levels, for example, Cr in kidney was 117.2 ± 12.6 ng/g tissue at 48 h. Co is more mobile than Cr, reaching higher levels at earlier time points. This could be due to local tissue binding of Cr. Exposure to Co-Cr particles in vivo altered antioxidant enzyme expression and activities. We observed induction of catalase protein in the liver and glutathione reductase (GR) and peroxidase (GPx) proteins in the spleen. Activities of catalase and GPx in the liver were significantly increased while that of GR was decreased in the kidney. Organs of mice with Co-Cr particle implantation were exposed to increased metal levels capable of inducing reactive oxygen species scavenging enzymes, suggesting the tissue may be subjected to oxidative stress; however, the overall antioxidant defence system was not markedly disturbed. Copyright © 2012 Wiley Periodicals, Inc.

  11. Particle-bound metal transport after removal of a small dam in the Pawtuxet River, Rhode Island, USA.

    Science.gov (United States)

    Katz, David R; Cantwell, Mark G; Sullivan, Julia C; Perron, Monique M; Burgess, Robert M; Ho, Kay T

    2017-07-01

    The Pawtuxet River in Rhode Island, USA, has a long history of industrial activity and pollutant discharges. Metal contamination of the river sediments is well documented and historically exceeded toxicity thresholds for a variety of organisms. The Pawtuxet River dam, a low-head dam at the mouth of the river, was removed in August 2011. The removal of the dam was part of an effort to restore the riverine ecosystem after centuries of anthropogenic impact. Sediment traps were deployed below the dam to assess changes in metal concentrations and fluxes (Ag, Cd, Cr, Cu, Ni, Pb, and Zn) from the river system into Pawtuxet Cove. Sediment traps were deployed for an average duration of 24 days each, and deployments continued for 15 months after the dam was removed. Metal concentrations in the trapped suspended particulate matter dropped after dam removal (e.g., 460 to 276 mg/kg for Zn) and remained below preremoval levels for most of the study. However, particle-bound metal fluxes increased immediately after dam removal (e.g., 1206 to 4248 g/day for Zn). Changes in flux rates during the study period indicated that river volumetric flow rates acted as the primary mechanism controlling the flux of metals into Pawtuxet Cove and ultimately upper Narragansett Bay. Even though suspended particulate matter metal concentrations initially dropped after removal of the dam, no discernable effect on the concentration or flux of the study metals exiting the river could be associated with removal of the Pawtuxet River dam. Integr Environ Assess Manag 2017;13:675-685. Published 2016. This article is a US Government work and is in the public domain in the USA. Published 2016. This article is a US Government work and is in the public domain in the USA.

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

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Villumsen, Arne

    2006-01-01

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

  13. Evaluation of the morphology of metal particles in intrinsic conductive polymer dispersions

    Science.gov (United States)

    Lempa, E.; Graßmann, C.; Rabe, M.; Schwarz-Pfeiffer, A.; van Langenhove, L.

    2017-10-01

    For the production of smart textiles the resistivity of prints and coatings with intrinsic conductive polymers is often too high and the performance properties not sufficient. The addition of metal components enhances many characteristics, however the choice of type of metal, morphology and application method influence results to great extend.

  14. Mineral and/or metal content as critical determinants of particle-induced release of IL-6 and IL-8 from A549 cells.

    Science.gov (United States)

    Hetland, R B; Refsnes, M; Myran, T; Johansen, B V; Uthus, N; Schwarze, P E

    2000-05-12

    Mineral particles in occupational exposure and ambient air particles may cause adverse health effects in humans. In this study the ability of different stone quarry particles to induce release of the proinflammatory cytokines interleukin-6 (IL-6) and interleukin-8 (IL-8) from human epithelial lung cells (A549) was investigated. Size distribution within the PM10 fractions was quite similar for all particle samples, whereas mineral content and metal composition differed. Particles, containing minerals such as quartz, amphibole, chlorite, and epidote, induced a marked increase in IL-6 and IL-8 release. Particles composed mainly of plagioclase were much less effective. The most potent particle samples exhibited a relatively high content of transition metals such as iron. Exposure to identical masses or surface areas resulted in the same order of potency among the different particle samples. Significant cytotoxicity was observed only at higher concentrations of particle exposure. Thus, mineral composition and/or metal contents of particles from different stone quarries were critical determinants for the marked differences in potency to induce cytokine responses in human epithelial lung cells.

  15. Mapping metals incorporation of a whole single catalyst particle using element specific X-ray nanotomography

    NARCIS (Netherlands)

    Meirer, Florian; Morris, Darius T; Kalirai, Samanbir; Liu, Yijin; Andrews, Joy C; Weckhuysen, Bert M

    2015-01-01

    Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to

  16. Heat Transfer While Incorporating Metal Particles in a Melting Support Plate

    Directory of Open Access Journals (Sweden)

    Mamontov Gennady Ya.

    2016-01-01

    Full Text Available The work defines and solves the heat transfer problem for “particle – support plate” system heated to high temperatures by means of mathematical simulation methods. In the course of the formulated problem, the numerical studies were carried out under conditions of a high density of the particle material in comparison with the support plate material.

  17. The Correlation of Structural, Chemical, and Electronic Properties of Small Metal Particles and Their Alloys

    Science.gov (United States)

    1983-01-01

    The low pressure interaction of CO with small Ru particles supported on ultrahigh vacuum (UHV) cleaved mica was studied using flash thermal desorption, Auger electron microscopy, transmission electron microscopy, and transmission electron diffraction. Average particle sizes for these experiments varied between 1.2 and 16 nm. A careful search for CO decomposition on the Ru particles revealed no evidence of dissociaiton over a temperature range and pressure range of 300 to 550 C and 10 to the minus 11th power to 10 to the minus 6th millibar, respectively. Cas and heat treatments caused significant morphological changes and dispersion in the Ru particles, which affected CO desorptiom These effects were dependent on the particle size.

  18. Green Synthesis of Smart Metal/Polymer Nanocomposite Particles and Their Tuneable Catalytic Activities

    Directory of Open Access Journals (Sweden)

    Noel Peter Bengzon Tan

    2016-03-01

    Full Text Available Herein we report a simple and green synthesis of smart Au and Ag@Au nanocomposite particles using poly(N-isopropylacrylamide/polyethyleneimine (PNIPAm/PEI core-shell microgels as dual reductant and templates in an aqueous system. The nanocomposite particles were synthesized through a spontaneous reduction of tetrachloroauric (III acid to gold nanoparticles at room temperature, and in situ encapsulation and stabilization of the resultant gold nanoparticles (AuNPs with amine-rich PEI shells. The preformed gold nanoparticles then acted as seed nanoparticles for further generation of Ag@Au bimetallic nanoparticles within the microgel templates at 60 °C. These nanocomposite particles were characterized by TEM, AFM, XPS, UV-vis spectroscopy, zeta-potential, and particle size analysis. The synergistic effects of the smart nanocomposite particles were studied via the reduction of p-nitrophenol to p-aminophenol. The catalytic performance of the bimetallic Ag@Au nanocomposite particles was 25-fold higher than that of the monometallic Au nanoparticles. Finally, the controllable catalytic activities of the Au@PNIPAm/PEI nanocomposite particles were demonstrated via tuning the solution pH and temperature.

  19. Distinguishing metal bioconcentration from particulate matter in moss tissue: Testing methods of removing particles attached to the moss surface

    Energy Technology Data Exchange (ETDEWEB)

    Spagnuolo, V.; Giordano, S. [Department of Biology, University of Naples Federico II, Via Cintia 4, I-80126 Napoli (Italy); Pérez-Llamazares, A.; Ares, A.; Carballeira, A.; Fernández, J.A. [Area de Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Aboal, J.R., E-mail: jesusramon.aboal@usc.es [Area de Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2013-10-01

    Accurate differentiation of the proportion of bioconcentrated metals (i.e. incorporated into cells) and the proportion that is not bioconcentrated (i.e. adsorbed at the surface) would lead to a better understanding of the uptake processes and would represent an advance in the use of mosses as biomonitors. Traditionally the methods used to remove contaminants that are not bioconcentrated were to wash the plant material with water or to apply the sequential elution technique, but nowadays both options are considered inaccurate for these purposes. The remaining possibilities are to clean the moss samples with a nitrogen jet or by power ultrasound. Samples of terrestrial moss Pseudoscleropodium purum (Hewd.) Fleisch. were collected from five sampling stations. Different nitrogen jet cleaning procedures and ultrasound cleaning procedures were applied to the mosses. To determine whether any of the treatments altered the membrane integrity of the moss samples, the concentrations of K were determined. The shoots were observed under a scanning electron microscope, and the size and number of particles were determined. Nitrogen jet cleaning was determined to be unacceptable because it damaged the phyllids and/or altered the membrane permeability and did not eliminate the particles from the moss surface. Moreover, ultrasound cleaning treatment should also discarded because of the loss of extracellular metals that are transferred to the water in which the moss is cleaned. - Highlights: • The cleaning of surface particles on mosses is an unresolved issue • The use of a nitrogen jet as cleaning procedure was ruled out • The use of ultrasound treatments as cleaning procedure was also discarded • Currently it is not possible to quantify the bioconcentrated metal fraction in mosses.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2002-02-05

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NO{sub x} concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end work is progress using an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. Progress in the Sixth Quarter (January 1, 2002 through March 31, 2002) was slow because of slagging problems in the combustor. These required the combustor to be rebuilt, a job that is not yet complete. A paper describing our results heretofore has been accepted by the Journal Environmental Science and Technology.

  1. Heat conduction in metal-filled polymers - The role of particle size, shape, and orientation

    Science.gov (United States)

    Hansen, D.; Tomkiewicz, R.

    1975-01-01

    This paper presents a new type of analysis for predicting the thermal conductivity of disperse composites from the properties of the component phases and elementary characterizations of particle shapes and orientation. This analysis successfully predicted the sensitivity to particle shape which was confirmed by experiments also reported in this paper. These results suggest that highly elongated particles may be used to achieve dramatic modifications of thermal conductivity and the analysis presented here may be a useful tool in the design or development of disperse composites of specific thermal conductivity. The analysis may also apply to other properties such as electrical conductivity or magnetic permeability.

  2. Heterogeneous reactions of HO2 with a variety of aerosol types. Effects of transition metal ions and irradiation

    Science.gov (United States)

    Heard, Dwayne; Moon, Daniel; Ingham, Trevor; Whalley, Lisa; Seakins, Paul; Baeza-Romero, Maria-Teresa

    2017-04-01

    The lifetime of HO2 is sufficiently long that uptake to aerosols may constitute an important component of its budget, yet quantitative comparisons of field-measured and modelled concentrations have been hampered by uncertainties in the uptake coefficient (γ) of HO2 to aerosols. An aerosol flow tube coupled with very sensitive detection of HO2 has been used to determine γ for HO2 onto a wide range of aerosol types including inorganic salt aerosols, dusts (terrestrial and cosmic), single component organic aerosols (including surfactants and sucrose), and secondary organic aerosol. The injection of the latter into the stratosphere has been suggested as one strategy to mitigate global warming, and the application of TiO2 coatings to surfaces within the urban environment is used to remove NO2 resulting from traffic emissions and to facilitate self-cleaning. Uptake coefficients were determined as a function of relative humidity (RH), transition metal ion concentration, aerosol viscosity and temperature. Uptake coefficients were determined for sub-micron TiO2 particles as a function of RH. Significant uptake was observed in the dark, with γ = 0.021 ± 0.001 for RH=11%, increasing with RH and apparently dependent upon the number of monolayers of water adsorbed onto the TiO2 surface. When the TiO2 particles were illuminated with near-UV radiation (365 nm) significant production of HO2 radicals was observed, displaying a complex dependence upon radiation flux, RH and total particle surface area. When inorganic salt aerosols were generated in the presence of transition metal ions (copper, iron and manganese, either studied singly or as mixtures), the removal of HO2 was catalyzed leading to an increase in γ, which was observed to be a complex function of the concentration of the free, uncomplexed ions.

  3. Heavy metal pollution decreases microbial abundance, diversity and activity within particle-size fractions of a paddy soil.

    Science.gov (United States)

    Chen, Junhui; He, Feng; Zhang, Xuhui; Sun, Xuan; Zheng, Jufeng; Zheng, Jinwei

    2014-01-01

    Chemical and microbial characterisations of particle-size fractions (PSFs) from a rice paddy soil subjected to long-term heavy metal pollution (P) and nonpolluted (NP) soil were performed to investigate whether the distribution of heavy metals (Cd, Cu, Pb and Zn) regulates microbial community activity, abundance and diversity at the microenvironment scale. The soils were physically fractionated into coarse sand, fine sand, silt and clay fractions. Long-term heavy metal pollution notably decreased soil basal respiration (a measurement of the total activity of the soil microbial community) and microbial biomass carbon (MBC) across the fractions by 3-45% and 21-53%, respectively. The coarse sand fraction was more affected by pollution than the clay fraction and displayed a significantly lower MBC content and respiration and dehydrogenase activity compared with the nonpolluted soils. The abundances and diversities of bacteria were less affected within the PSFs under pollution. However, significant decreases in the abundances and diversities of fungi were noted, which may have strongly contributed to the decrease in MBC. Sequencing of denaturing gradient gel electrophoresis bands revealed that the groups Acidobacteria, Ascomycota and Chytridiomycota were clearly inhibited under pollution. Our findings suggest that long-term heavy metal pollution decreased the microbial biomass, activity and diversity in PSFs, particularly in the large-size fractions. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Exploring methods for compositional and particle size analysis of noble metal nanoparticles in Daphnia manga

    NARCIS (Netherlands)

    Krystek, P.W.; Brandsma, S.H.; Leonards, P.E.G.; de Boer, J.

    2016-01-01

    The identification and quantification of the bioaccumulation of noble metal engineered nanoparticles (ENPs) by aquatic organisms is of great relevance to understand the exposure and potential toxicity mechanisms of nanoscale materials. Four analytical scenarios were investigated in relation to

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

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2002-08-15

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

  6. Facile fabrication of core-in-shell particles by the slow removal of the core and its use in the encapsulation of metal nanoparticles.

    Science.gov (United States)

    Choi, Won San; Koo, Hye Young; Kim, Dong-Yu

    2008-05-06

    Core-in-shell particles with controllable core size have been fabricated from core-shell particles by means of the controlled core-dissolution method. These cores in inorganic shells were employed as scaffolds for the synthesis of metal nanoparticles. After dissolution of the cores, metal nanoparticles embedded in cores were encapsulated into the interior of shell, without any damage or change. This article describes a very simple method for deriving core-in-shell particles with controllable core size and encapsulation of nanoparticles into the interior of shell.

  7. Numerical study of melted particles crush metallic substrates and the interaction between particles and a plasma beam in the thermal projection process

    Energy Technology Data Exchange (ETDEWEB)

    Kriba, Ilhem [Plasma Laboratory, Faculty of Sciences, Department of Physics, University of Ouargla, Ouargla (Algeria)], E-mail: ilhem_kriba@yahoo.fr; Djebaili, A. [Laboratory of Chemistry and Environment Chemistry L.C.C.E, University of Batna (Algeria)

    2009-03-01

    Plasma spray processes have been widely used to produce high performance coatings of a wide range of materials (metallic, non-metallic, and ceramics), offering protection from, e.g. wear, extreme temperature, chemical attack and environmental corrosion. To obtain good quality coatings, spray parameters must be carefully selected. Due to the large variety in process parameters, it is difficult to optimize the process for each specific coating and substrate combinations. Furthermore modelling the spray process allows a better understanding of the process sequences during thermal spraying. The simulation of coating formation to estimate the process parameters is an important tool to develop new coating structures with defined properties. In this work, the process of plasma sprayed coating has been analyzed by numerical simulation. Commercial code is used to predict the plasma jet characteristics, plasma-particle interaction, and coating formation. Using this model we can obtain coating microstructure and characteristics which form a foundation for further improvement of an advanced ceramic coating build up model.

  8. Mechanical Properties of Individual Microgel Particles

    Science.gov (United States)

    Hashmi, Sara; Dufresne, Eric

    2009-03-01

    Microgels are important materials for both basic science and engineering and have wide applications from the study of phase transitions to the delivery of drugs. These micron and sub-micron particles, made of hydrogel materials, respond to solvent conditions. The most common microgels are environmentally sensitive, responding to temperature and pH. Our material of interest, poly(N-isopropylacrylamide) or NIPAM, undergoes a deswelling transition above a critical temperature. The deswelling behavior of this polymeric material has been thoroughly studied in ensemble microgel systems as well as in bulk hydrogel samples. We present measurements of the elastic properties of single microgel particles using atomic force microscopy. We observe a stiffening of the Young's modulus by an order of magnitude at temperatures well above the transition, where the cross-linked polymer network has fully collapsed. Interestingly, near the transition we observe a comparable softening of the material.

  9. Slow waves in microchannel metal waveguides and application to particle acceleration

    OpenAIRE

    L. C. Steinhauer; W. D. Kimura

    2003-01-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong ex...

  10. Effect of particle size on the thermal conductivity of nanofluids containing metallic nanoparticles

    National Research Council Canada - National Science Library

    Warrier, Pramod; Teja, Amyn

    2011-01-01

    .... Although literature data could be correlated well using the model, the effect of the size of the particles on the effective thermal conductivity of the nanofluid could not be elucidated from these data...

  11. Surface enhanced Raman scattering of monolayer MX2 with metallic nano particles

    Science.gov (United States)

    Zhang, Duan; Wu, Ye-Cun; Yang, Mei; Liu, Xiao; Coileáin, Cormac Ó.; Abid, Mourad; Abid, Mohamed; Wang, Jing-Jing; Shvets, Igor; Xu, Hongjun; Chun, Byong Sun; Liu, Huajun; Wu, Han-Chun

    2016-07-01

    Monolayer transition metal dichalcogenides MX2 (M = Mo, W; X = S) exhibit remarkable electronic and optical properties, making them candidates for application within flexible nano-optoelectronics. The ability to achieve a high optical signal, while quantitatively monitoring strain in real-time is the key requirement for applications in flexible sensing and photonics devices. Surface-enhanced Raman scattering (SERS) allows us to achieve both simultaneously. However, the SERS depends crucially on the size and shape of the metallic nanoparticles (NPs), which have a large impact on its detection sensitivity. Here, we investigated the SERS of monolayer MX2, with particular attention paid to the effect of the distribution of the metallic NPs. We show that the SERS depends crucially on the distribution of the metallic NPs and also the phonon mode of the MX2. Moreover, strong coupling between MX2 and metallic NPs, through surface plasmon excitation, results in splitting of the and modes and an additional peak becomes apparent. For a WS2-Ag system the intensity of the additional peak increases exponentially with local strain, which opens another interesting window to quantitatively measure the local strain using SERS. Our experimental study may be useful for the application of monolayer MX2 in flexible nano-optoelectronics.

  12. Single particle tracking of internalized metallic nanoparticles reveals heterogeneous directed motion after clathrin dependent endocytosis in mouse chromaffin cells

    Science.gov (United States)

    Gabriel, Manuela; Moya-Díaz, José; Gallo, Luciana I.; Marengo, Fernando D.; Estrada, Laura C.

    2018-01-01

    Most accepted single particle tracking methods are able to obtain high-resolution trajectories for relatively short periods of time. In this work we apply a straightforward combination of single-particle tracking microscopy and metallic nanoparticles internalization on mouse chromaffin cells to unveil the intracellular trafficking mechanism of metallic-nanoparticle-loaded vesicles (MNP-V) complexes after clathrin dependent endocytosis. We found that directed transport is the major route of MNP-Vs intracellular trafficking after stimulation (92.6% of the trajectories measured). We then studied the MNP-V speed at each point along the trajectory, and found that the application of a second depolarization stimulus during the tracking provokes an increase in the percentage of low-speed trajectory points in parallel with a decrease in the number of high-speed trajectory points. This result suggests that stimulation may facilitate the compartmentalization of internalized MNPs in a more restricted location such as was already demonstrated in neuronal and neuroendocrine cells (Bronfman et al 2003 J. Neurosci. 23 3209–20). Although further experiments will be required to address the mechanisms underlying this transport dynamics, our studies provide quantitative evidence of the heterogeneous behavior of vesicles mobility after endocytosis in chromaffin cells highlighting the potential of MNPs as alternative labels in optical microscopy to provide new insights into the vesicles dynamics in a wide variety of cellular environments.

  13. Adverse health effects of Asian dust particles and heavy metals in Japan.

    Science.gov (United States)

    Onishi, Kazunari; Otani, Shinji; Yoshida, Atsushi; Mu, Haosheng; Kurozawa, Youichi

    2015-03-01

    Asian dust events are now considered an environmental problem rather than a natural seasonal phenomenon. In this study, we evaluated the associations between daily adverse health effects and Asian dust events in Yonago, Japan. Participants included 54 healthy volunteers, who were distributed survey sheets on nasal, ocular, respiratory, and skin effects in February 2009. Moreover, we collected meteorological and air pollutant (nitric oxide, sulfur dioxide, suspended particulate matter) data and determined pollen and metallic element concentrations in total suspended particulates. Both soil-derived metals (Fe, Ca, Al) and contaminating metals (Pb, Cr, Mn, Ni, Zn) were significantly increased on Asian dust days. Multiple regression analyses showed that the score of the skin effect was significantly associated with the levels of suspended particulate matter and Ni. The results show that increased air pollutants on Asian dust days may have skin effects. © 2011 APJPH.

  14. Metal matrix composite of an iron aluminide and ceramic particles and method thereof

    Science.gov (United States)

    Schneibel, Joachim H.

    1997-01-01

    A metal matrix composite comprising an iron aluminide binder phase and a ceramic particulate phase such as titanium diboride, zirconium diboride, titanium carbide and tungsten carbide is made by heating a mixture of iron aluminide powder and particulates of one of the ceramics such as titanium diboride, zirconium diboride, titanium carbide and tungsten carbide in a alumina crucible at about 1450.degree. C. for about 15 minutes in an evacuated furnace and cooling the mixture to room temperature. The ceramic particulates comprise greater than 40 volume percent to about 99 volume percent of the metal matrix composite.

  15. Incorporation of cobalt and nickel metal nano-particles in nano-grain ...

    Indian Academy of Sciences (India)

    Precursor solutions of cobalt/nickel incorporated nano-grain zirconia films were prepared from aquo-organic solutions of zirconium oxychloride octahydrate and corresponding transition metal nitrate. The films were deposited onto silica glass substrate by the dipping technique. Annealing was made at different temperatures ...

  16. Formation of Nanoscale Metallic Glassy Particle Reinforced Al-Based Composite Powders by High-Energy Milling

    Directory of Open Access Journals (Sweden)

    Weiwen Zhang

    2017-10-01

    Full Text Available The initial microstructure and mechanical properties of composite powders have a vital role in determining the microstructure and mechanical properties of the subsequent consolidated bulk composites. In this work, Al-based matrix composite powders with a dense and uniform distribution of metallic glass nanoparticles were obtained by high-energy milling. The results show that high-energy milling is an effective method for varying the microstructure and mechanical properties of the composite powders, thereby offering the ability to control the final microstructure and properties of the bulk composites. It was found that the composite powders show a deformed layer combined with an undeformed core after milling. The reinforcements, metallic glass microparticles, are fractured into dense distributed nanoparticles in the deformed layer, owing to the severe plastic deformation, while in the undeformed core, the metallic glass microparticles are maintained. Therefore, a bimodal structure was obtained, showing a mechanical bimodal structure that has much higher hardness in the outer layer than the center core. The hardness of the composite particles increases significantly with increasing milling time, due to dispersion strengthening and work hardening.

  17. Altered ion transport in normal human bronchial epithelial cells following exposure to chemically distinct metal welding fume particles.

    Science.gov (United States)

    Fedan, Jeffrey S; Thompson, Janet A; Meighan, Terence G; Zeidler-Erdely, Patti C; Antonini, James M

    2017-07-01

    Welding fume inhalation causes pulmonary toxicity, including susceptibility to infection. We hypothesized that airway epithelial ion transport is a target of fume toxicity, and investigated the effects of fume particulates from manual metal arc-stainless steel (MMA-SS) and gas metal arc-mild steel (GMA-MS) on ion transport in normal human bronchial epithelium (NHBE) cultured in air-interface. MMA-SS particles, more soluble than GMA-MS particles, contain Cr, Ni, Fe and Mn; GMA-MS particles contain Fe and Mn. MMA-SS or GMA-MS particles (0.0167-166.7μg/cm 2 ) were applied apically to NHBEs. After 18h transepithelial potential difference (V t ), resistance (R t ), and short circuit current (I sc ) were measured. Particle effects on Na + and Cl¯ channels and the Na + ,K + ,2Cl¯-cotransporter were evaluated using amiloride (apical), 5-nitro-2-[(3-phenylpropyl)amino]benzoic acid (NPPB, apical), and bumetanide (basolateral), respectively. MMA-SS (0.0167-16.7μg/cm 2 ) increased basal V t . Only 16.7μg/cm 2 GMA-MS increased basal V t significantly. MMA-SS or GMA-MS exposure potentiated I sc responses (decreases) to amiloride and bumetanide, while not affecting those to NPPB, GMA-MS to a lesser degree than MMA-SS. Variable effects on R t were observed in response to amiloride, and bumetanide. Generally, MMA-SS was more potent in altering responses to amiloride and bumetanide than GMA-MS. Hyperpolarization occurred in the absence of LDH release, but decreases in V t , R t , and I sc at higher fume particulate doses accompanied LDH release, to a greater extent for MMA-SS. Thus, Na + transport and Na + ,K + ,2Cl¯-cotransport are affected by fume exposure; MMA-MS is more potent than GMA-MS. Enhanced Na + absorption and decreased airway surface liquid could compromise defenses against infection. Published by Elsevier Inc.

  18. Nitrite reduction over Pd supported CNFs: Metal particle size effect on selectivity

    NARCIS (Netherlands)

    Chinthaginjala, J.K.; Villa, A.; Su, D.S.; Mojet, Barbara; Lefferts, Leonardus

    2012-01-01

    Pd catalysts supported on carbon-nano-fibers (CNFs) were synthesized via Pd colloids stabilized with polyvinyl-alcohol (PVA). Pd catalysts with narrow particle size distributions and mean Pd sizes between 2.6 and 30 nm were immobilized on CNFs. Characterization with CO-chemisorption and transmission

  19. Investigation of interface boundary occurring during cold gas-dynamic spraying of metallic particles

    CERN Document Server

    Bolesta, A V; Sharafutdinov, M R; Tolochko, B P

    2001-01-01

    An interface boundary occurring during cold gas dynamic spraying of aluminum particles on a nickel substrate has been studied by the method of X-ray grazing diffraction. Presence of boundary phase of the intermetallic compound Ni sub 3 Al was found.

  20. Is there a contraction of the interatomic distance in small metal particles?

    DEFF Research Database (Denmark)

    Hansen, Lars Bruno; Stoltze, Per; Nørskov, Jens Kehlet

    1990-01-01

    A theoretical analysis is made of the bond lengths of small (100–1000 atoms) Cu particles at various temperatures. The interatomic interactions are calculated using the effective-medium theory and the finite-temperature properties obtained from a molecular-dynamics simulation. We find only very s...

  1. Metal-bearing Aerosols of Industrial Origin from Multiple Sources in South Phoenix, Arizona: Separating Similar Particle Types with Minor Element Differences Using Automated SEM Analysis of Large Populations of Particles

    Science.gov (United States)

    Anderson, J.; Hua, X.

    2009-12-01

    Particulate pollution, especially PM10, in the Greater Phoenix (Maricopa County) airshed is a long-standing problem. While much of the PM10 can be ascribed to soil dust entrained by human activity (e.g., sand and gravel mining and other construction-support activities both directly and indirectly), south-central and southwest Phoenix have a significant number of industrial sources of metal-bearing particles. Many of these particles are dominated compositionally by Fe but have minor elements such as Cu, Ba, Mn, Cr, Ni and others which can be statistically mutually exclusive when large populations are looked at with automated Scanning Electron Microscopy (SEM). Bulk aerosol chemical analysis of high-volume samples shows the presence of these elements, including the dominance of Fe at times, but there are far more potential sources than can ever by deduced by principal component analysis of the bulk sample data. Because of the potential toxic nature of these industrial particles, about which there is considerable community concern, identifying the multiple sources is a key step in mitigating the pollution. Also present in these industrial aerosols are mostly submicron particles containing Sr, Sb, V, Cd, and other elements in various combinations. While analyzing the minor element content of submicron particles, some of which are beam-sensitive, pushes the limits of automated SEM techniques, this is the only way to examine large, statistically significant particle populations in many samples on an individual-particle basis. The elemental associations in these unusual metal-bearing particles tend to be the key to source identification. Particle morphology is also important in separating particle types from different sources in these populations. For instance, one of major sources of Fe-dominant particles in southwest Phoenix is a scrap metal operation that uses a “mega-shredder”. This mega-shredder generates enough heat to melt some of the metal and produce roughly

  2. CHARACTERISATION AND MEASUREMENT TO THE SUB-MICRON SCALE OF A REFERENCE WIRE POSITION CARACTERISATION ET MESURE SUB-MICROMETRIQUE DE LA POSITION D’UN FIL DE REFERENCE

    CERN Document Server

    SANZ , Claude; MAINAUD DURAND , Hélène; MORANTZ , Paul; SHORE , Paul

    2015-01-01

    L’étude suivante est réalisée dans le cadre du projet PACMAN (a study on Particle Accelerator Components Metrology and Alignment to the Nanometre scale) : une étude sur la métrologie et l’alignement à l’échelle nanométrique des composants d’un accélérateur de particules. C’est un programme Marie Curie supporté par la Commission Européenne et hébergé par le CERN. Le but de ce programme est de faire travailler en équipe de jeunes chercheurs sur le développement d’un banc de pré-alignement pour l’accélérateur linéaire CLIC (Compact Linear Collider). Sur ce banc, chaque composant sera aligné au niveau requis en une seule opération basée sur l’utilisation d’un fil tendu. Pendant cette opération, le fil matérialisera les axes magnétiques et électriques des composants, c’est-à-dire qu’il sera à la position théorique du faisceau de particules. Puis il servira de référence et la position de son axe sera mesurée avec autant de précision que possible par une machin...

  3. Laser processing issues of nanosized intermetallic Fe-Sn and metallic Sn particles

    Science.gov (United States)

    Alexandrescu, R.; Morjan, I.; Dumitrache, F.; Birjega, R.; Fleaca, C.; Morjan, Iuliana; Scarisoreanu, M.; Luculescu, C. R.; Dutu, E.; Kuncser, V.; Filoti, G.; Vasile, E.; Ciupina, V.

    2012-09-01

    Intermetallic Fe-Sn and nanocrystalline metallic Sn nanoparticles have been successfully synthesized from organic precursors using the laser pyrolysis technique with ethylene as sensitizer. Nano-structured Sn (single phase) was prepared by the pyrolysis of Sn(CH3)4 (TMT) vapors. Controlled Fe/Sn atomic ratios, ranging from 0.69 to 1.64 were obtained for the prepared Fe-Sn nanopowders by the control of Fe(CO)5 and TMT flows, respectively. XRD studies evidence three main phases: the tetragonal metallic Sn phase and the intermetallic FeSn2 phase and, to a much lesser extent, the cubic ternary carbide Fe3SnC. Complex core-shell structural characteristics were found by HRTEM analysis. More complete information about the Fe phase distributions in the new intermetallic Fe-Sn nanomaterial is provided by temperature dependent 57Fe Mössbauer spectroscopy.

  4. Effect of flyash particles with aluminium melt on the wear of aluminium metal matrix composites

    Directory of Open Access Journals (Sweden)

    Vipin K. Sharma

    2017-08-01

    Full Text Available The present work deals with the fabrication and tribological testing of an aluminium flyash composite. The metal matrix selected was aluminium and flyash contents in different percentages were reinforced in it to fabricate the required metal matrix composite (MMC. Stir casting method was used to fabricate the MMC with 2–4–6% weight of flyash contents in aluminium. Tribological analysis of the tribo pairs formed between the smooth surfaces of cast iron disc and smooth MMC pin has been considered and friction force and wear of the MMC were investigated by using a Pin-on-disc setup. It was observed that the MMC with 6% weight of flyash content in aluminium matrix results in less wear (0.32 g and 4% weight of flyash content gives the low coefficient of friction (0.12 between the tribopairs of cast iron surface and MMC surface.

  5. Synthesis of Nanostructured/Macroscopic Low-Density Copper Foams Based on Metal-Coated Polymer Core-Shell Particles.

    Science.gov (United States)

    Kim, Sung Ho; Bazin, Nick; Shaw, Jessica I; Yoo, Jae-Hyuck; Worsley, Marcus A; Satcher, Joe H; Sain, John D; Kuntz, Joshua D; Kucheyev, Sergei O; Baumann, Theodore F; Hamza, Alex V

    2016-12-21

    A robust, millimeter-sized low-density Cu foam with ∼90% (v/v) porosity, ∼30 nm thick walls, and ∼1 μm diameter spherical pores is prepared by the slip-casting of metal-coated polymer core-shell particles followed by a thermal removal of the polymer. In this paper, we report our key findings that enable the development of the low-density Cu foams. First, we need to synthesize polystyrene (PS) particles coated with a very thin Cu layer (in the range of tens of nanometers). A simple reduction in the amount of Cu deposited onto the PS was not sufficient to form such a low-density Cu foams due to issues related to foam collapse and densification upon the subsequent polymer removal step. Precise control over the morphology of the Cu coating on the particles is essential for the synthesis of a lower density of foams. Second, improving the dispersion of PS-Cu particles in a suspension used for the casting as well as careful optimization of a baking condition minimize the formation of irregular large voids, leading to Cu foams with a more uniform packing and a better connectivity of neighboring Cu hollow shells. Finally, we analyzed mechanical properties of the Cu foams with a depth-sensing indentation test. The uniform Cu foams show a significant improvement in mechanical properties (∼1.5× modulus and ∼3× hardness) compared to those of uncontrolled foam samples with a similar foam density but irregular large voids. Higher surface areas and a good electric conductivity of the Cu foams present a great potential to future applications.

  6. The effect of particle size on the dehydration/rehydration behaviour of lactose.

    Science.gov (United States)

    Crisp, J L; Dann, S E; Edgar, M; Blatchford, C G

    2010-05-31

    Ethanolic suspensions of spray dried and micronized alpha lactose monohydrate (L(alpha)xH(2)O) with average particle size between 3 and 200 microm, have been prepared and their dehydration behaviour was investigated by (13)C CP-MASNMR spectroscopy. Sub-micron lactose suspension prepared by a novel high pressure homogenisation method has been compared with the standard ethanolic suspensions of (L(alpha).H(2)O prepared by reflux or static room temperature methods. In all cases, suspensions were shown to contain the stable anhydrous form of lactose ((L(alpha)(S)). Several approaches were employed to remove ethanol from these suspensions and the resulting dry lactose powders were then analysed by FT-IR, PXRD and SEM to evaluate the effect of drying procedure on type and distribution of lactose polymorphs and particle size. For samples with mean particle size greater than 1 microm, the stable anhydrous polymorphic form of lactose was retained on removal of the ethanol, although differences in the morphology and particle size of the crystals were apparent depending on method of suspension formation. Sub-micron (L(alpha)(S), while stable in dry conditions, has been shown to be less stable to atmospheric water vapour than (L(alpha)(S) with particle size between 3 and 200 microm. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  7. Mass production of polymer nano-wires filled with metal nano-particles

    OpenAIRE

    Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

    2017-01-01

    Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable fo...

  8. Laser Doppler anemometry measurements in a circulating fluidized bed of metal particles

    DEFF Research Database (Denmark)

    Ibsen, Claus Hübbe; Solberg, Tron; Hjertager, Bjørn Helge

    2002-01-01

    Laser Doppler Anemometry (LDA) measurements were performed in a 1/9 scale model of a 12 MW circulating fluidized bed (CFB) boiler. The model was operated according to scaling laws. The 2D-LDA system used was positioned in two different ways to obtain the three velocity components u, v and w...... of the solid phase from which the particle kinetic stresses were determined. The measured velocity profiles are in agreement with previous data from the full-scale boiler, i.e. showing a flat profile over the core region of the riser with a pronounced wall layer. The particle kinetic stresses are found...... to be anisotropic and strongly influenced by large scale effects originating from the bottom-bed bubbles....

  9. Effect of particle size on adsorption of heavy metals using chemically ...

    African Journals Online (AJOL)

    The effect of particle size on the bioremediation of Pb(II), Zn(II), Cd (II) and Hg(II) ions from synthetic aqueous effluents using unmodified and carboxymethylated fluted pumpkin and broad-leafed pumpkin pods was investigated in a batch system. 1.2 g of adsorbents was used in each sorption experiment at 25 °C and pH ...

  10. Laser processing issues of nanosized intermetallic Fe-Sn and metallic Sn particles

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrescu, R., E-mail: ralexandrescu2001@yahoo.co.uk [National Institute for Lasers, Plasma and Radiation Physics Bucharest, POB MG-36, 077125 (Romania); Morjan, I.; Dumitrache, F.; Birjega, R.; Fleaca, C.; Morjan, Iuliana; Scarisoreanu, M.; Luculescu, C.R.; Dutu, E. [National Institute for Lasers, Plasma and Radiation Physics Bucharest, POB MG-36, 077125 (Romania); Kuncser, V.; Filoti, G. [National Institute of Materials Physics, POB MG-7, 077125 Bucharest-Magurele (Romania); Vasile, E. [Metav R and D, Rosetti 31, Bucharest (Romania); Ciupina, V. [Ovidius University of Constanta, Bd. Mamaia 124, Constanta (Romania)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Intermetallic Fe-Sn and metallic Sn nanoparticles synthesized by laser pyrolysis. Black-Right-Pointing-Pointer Fe(CO){sub 5} and Sn(CH{sub 3}){sub 4} were used as precursors. Black-Right-Pointing-Pointer FeSn{sub 2}, Sn and Fe{sub 3}SnC phases were identified by XRD. Black-Right-Pointing-Pointer Complex core-shell structural characteristics were found by HRTEM analysis. Black-Right-Pointing-Pointer Higher magnetization was found in samples with increased Fe/Sn atomic ratio. - Abstract: Intermetallic Fe-Sn and nanocrystalline metallic Sn nanoparticles have been successfully synthesized from organic precursors using the laser pyrolysis technique with ethylene as sensitizer. Nano-structured Sn (single phase) was prepared by the pyrolysis of Sn(CH{sub 3}){sub 4} (TMT) vapors. Controlled Fe/Sn atomic ratios, ranging from 0.69 to 1.64 were obtained for the prepared Fe-Sn nanopowders by the control of Fe(CO){sub 5} and TMT flows, respectively. XRD studies evidence three main phases: the tetragonal metallic Sn phase and the intermetallic FeSn{sub 2} phase and, to a much lesser extent, the cubic ternary carbide Fe{sub 3}SnC. Complex core-shell structural characteristics were found by HRTEM analysis. More complete information about the Fe phase distributions in the new intermetallic Fe-Sn nanomaterial is provided by temperature dependent {sup 57}Fe Moessbauer spectroscopy.

  11. Size-Resolved Characterization of Particles and Fibers Released during Abrasion of Fiber-Reinforced Composite in a Workplace Influenced by Ambient Background Sources

    DEFF Research Database (Denmark)

    Kling, Kirsten I.; Levin, Marcus; Jensen, Alexander C. O.

    2016-01-01

    We demonstrate the use of high-to low-resolution microscopy and particle chemical analysis during normal vacuum and cryo-conditions to identify the nature and relative abundances of process-generated particles and fibers from sanding of a glass and carbon fiber epoxy layer-composite in a workplace...... of ambient particles to the background in the production facility was observed in the sub-micron size range. Fibers are posing a dominant exposure risk in the micron size range, with carbon fibers dominating in count....

  12. Investigation of the effects of intense pulsed particle beams on the durability of metal-to-plastic interfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Somuri V.; Renk, Timothy J.; Provencio, Paula Polyak; Petersen, Donald W. (University of Alabama, Birmingham, AL); Petersen, Thomas D. (University of California, San Diego, CA); Buchheit, Thomas Edward; McNulty, Donald E. (DePuy Orthopaedic, Inc., Warsaw, IN); Engelko, Vladimir (D. V. Efremov Scientific Research Institute of the Electrophysical Apparatus, St. Petersburg, Russia)

    2005-02-01

    We have investigated the potential for intense particle beam surface modification to improve the mechanical properties of materials commonly used in the human body for contact surfaces in, for example, hip and knee implants. The materials studied include Ultra-High Molecular Weight Polyethylene (UHMWPE), Ti-6Al-4Al (titanium alloy), and Co-Cr-Mo alloy. Samples in flat form were exposed to both ion and electron beams (UHMWPE), and to ion beam treatment (metals). Post-analysis indicated a degradation in bulk properties of the UHMWPE, except in the case of the lightest ion fluence tested. A surface-alloyed Hf/Ti layer on the Ti-6Al-4V is found to improve surface wear durability, and have favorable biocompatibility. A promising nanolaminate ceramic coating is applied to the Co-Cr-Mo to improve surface hardness.

  13. Pulmonary toxicity after exposure to military-relevant heavy metal tungsten alloy particles

    Energy Technology Data Exchange (ETDEWEB)

    Roedel, Erik Q., E-mail: Erik.Roedel@amedd.army.mil [Department of General Surgery, Tripler Army Medical Center, Honolulu, HI 96859 (United States); Cafasso, Danielle E., E-mail: Danielle.Cafasso@amedd.army.mil [Department of General Surgery, Tripler Army Medical Center, Honolulu, HI 96859 (United States); Lee, Karen W.M., E-mail: Karen.W.Lee@amedd.army.mil [Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, HI 96859 (United States); Pierce, Lisa M., E-mail: Lisa.Pierce@amedd.army.mil [Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, HI 96859 (United States)

    2012-02-15

    Significant controversy over the environmental and public health impact of depleted uranium use in the Gulf War and the war in the Balkans has prompted the investigation and use of other materials including heavy metal tungsten alloys (HMTAs) as nontoxic alternatives. Interest in the health effects of HMTAs has peaked since the recent discovery that rats intramuscularly implanted with pellets containing 91.1% tungsten/6% nickel/2.9% cobalt rapidly developed aggressive metastatic tumors at the implantation site. Very little is known, however, regarding the cellular and molecular mechanisms associated with the effects of inhalation exposure to HMTAs despite the recognized risk of this route of exposure to military personnel. In the current study military-relevant metal powder mixtures consisting of 92% tungsten/5% nickel/3% cobalt (WNiCo) and 92% tungsten/5% nickel/3% iron (WNiFe), pure metals, or vehicle (saline) were instilled intratracheally in rats. Pulmonary toxicity was assessed by cytologic analysis, lactate dehydrogenase activity, albumin content, and inflammatory cytokine levels in bronchoalveolar lavage fluid 24 h after instillation. The expression of 84 stress and toxicity-related genes was profiled in lung tissue and bronchoalveolar lavage cells using real-time quantitative PCR arrays, and in vitro assays were performed to measure the oxidative burst response and phagocytosis by lung macrophages. Results from this study determined that exposure to WNiCo and WNiFe induces pulmonary inflammation and altered expression of genes associated with oxidative and metabolic stress and toxicity. Inhalation exposure to both HMTAs likely causes lung injury by inducing macrophage activation, neutrophilia, and the generation of toxic oxygen radicals. -- Highlights: ► Intratracheal instillation of W–Ni–Co and W–Ni–Fe induces lung inflammation in rats. ► W–Ni–Co and W–Ni–Fe alter expression of oxidative stress and toxicity genes. ► W

  14. The use of visible light and metal oxide nano particles for pathogen inactivation

    Science.gov (United States)

    Lubart, R.; Lipovski, A.; Gedanken, A.

    2012-09-01

    Since the effectiveness of antibiotic treatment is decreasing due to the development of resistant strains, alternative approaches for destroying microorganisms are needed. In this review we summarize new technologies that might be effective for pathogen inactivation. In the past we found that intense blue light could be used for bacterial eradication. The phototoxic effect correlated with the amount of reactive oxygen species (ROS) generated by the bacteria due to illumination. Recently it has been shown that the effect of light can be enhanced by introducing metal oxide nanoparticles (nps) to the bacteria prior to irradiation. This led us to suggest combining nanoparticles with visible light irradiation for pathogen eradication. We have shown that combination of illumination with the nanoparticles (ZnO or TiO2) resulted in a marked increase in the reduction of bacterial viability to a mean reduction of 80-90% for both nanoaprticles. As a matter of fact metal oxide nps alone can be used for bacteria destruction. The advantage of our approach is the use of lower concentrations of nps, combined with reduced light intensity that is less toxic to the host tissue. To further avoid the toxicity of metal oxides nps on healthy tissue it is possible to coat their surfaces with various substrates including ceramics and polymers. Recently Zinc oxide nanoparticles have been synthesized and deposited on the surface of cotton fabrics using ultrasound irradiation. Thus in the future we will try to treat infected wounds with transparent bandages coated with ZnO that will be applied to the wounds prior to irradiation.

  15. Microstructure of Ti6Al4V reinforced by coating W particles through laser metal deposition

    CSIR Research Space (South Africa)

    Ndou, N

    2016-10-01

    Full Text Available of the surface [4]. The cross-section of the microstructure were characterised by using X-ray energy dispersive spectroscopy (EDS). The effect of the different laser power in LMD processes were compared against the resulting microstructure and micro...-hardness on metallic material with an indentation weight of 500 g was used, and a spacing time of 10s, spacing between the indentations was 12µm following the ASTM E384-11el standard [10]. All the samples were cleaned so that defects could be avoided. The grinding...

  16. Correlating metal poisoning with zeolite deactivation in an individual catalyst particle by chemical and phase-sensitive X-ray microscopy.

    Science.gov (United States)

    Ruiz-Martínez, Javier; Beale, Andrew M; Deka, Upakul; O'Brien, Mathew G; Quinn, Paul D; Mosselmans, J Fred W; Weckhuysen, Bert M

    2013-06-03

    Fluid catalytic cracking (FCC) is the main conversion process used in oil refineries. An X-ray microscopy method is used to show that metal poisoning and related structural changes in the zeolite active material lead to a non-uniform core–shell deactivation of FCC catalyst particles. The study links the detrimental effect of V and Ni poisoning with zeolite destruction and dealumination in a spatial manner within a single FCC catalyst particle.

  17. Potential health risk for residents around a typical e-waste recycling zone via inhalation of size-fractionated particle-bound heavy metals.

    Science.gov (United States)

    Huang, Chun-Li; Bao, Lian-Jun; Luo, Pei; Wang, Zhao-Yi; Li, Shao-Meng; Zeng, Eddy Y

    2016-11-05

    Health risk of residents dwelling around e-waste recycling zones has been a global concern, but has not been adequately examined. The present study was intended to evaluate the potential health risk of residents through inhalation exposure to size-fractionated particle-bound heavy metals in a typical e-waste recycling zone, South China. Anthropogenic metals (Zn, Se, Pb, Sb, As, and Cd) were predominantly enriched in fine particles (Dp1.8μm). Although the daily inhalation intakes of the target metals were significantly lower than those through food consumption and ingestion of house dust, the hazard quotients of total metals for adults (95% CI: 1.0-5.5) and children (95% CI: 3.0-17) were greater than 1. Moreover, the incremental lifetime cancer risks of five carcinogenic metals (Cr, Co, Ni, As, and Cd) for adults and children were 1.3×10(-3) (95% CI: 4.1×10(-4)-3.0×10(-3)) and 3.9×10(-3) (95% CI: 1.3×10(-3)-8.6×10(-3)), respectively, substantially higher than the acceptable cancer risk range of 10(-6)-10(-4). All these findings suggested that health risks were high for local residents dwelling around the e-waste recycling zone through inhalation exposure to particle-bound heavy metals, for both adults and children. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. 1- and 2-particle Microrheology of Hyaluronic Acid

    Science.gov (United States)

    Sagan, Austin; Kearns, Sarah; Ross, David; Das, Moumita; Thurston, George; Franklin, Scott

    2015-03-01

    Hyaluronic acid (also called HA or Hyaluronan) is a high molecular weight polysaccaride ubiquitous in the extracellular matrix of soft tissue such as cartilage, skin, the eye's vitreous gel and synovial fluid. It has been shown to play an important role in mechanotransduction, cell migration and proliferation, and in tissue morphodynamics. We present a confocal microrheology study of hyaluronic acid of varying concentrations. The mean squared displacement (MSD) of sub-micron colloidal tracer particles is tracked in two dimensions and shows a transition from diffusive motion at low concentrations to small-time trapping by the protein network as the concentration increases. Correlations between particle motion can be used to determine an effective mean-squared displacement which deviates from the single-particle MSD as the fluid becomes less homogeneous. The real and effective mean-squared displacements are used to probe the local and space-averaged frequency dependent rheological properties of the fluid as the concentration changes.

  19. Columnar-to-Equiaxed Transition in Metal-Matrix Composites Reinforced with Silicon Carbide Particles

    Directory of Open Access Journals (Sweden)

    Alicia E. Ares

    2013-01-01

    Full Text Available The present work is focused on the study of the effect of directional heat extraction on the silicon-carbide (SiC distribution in zinc-aluminum matrix composites (MMCs and on the columnar-to-equiaxed (CET position in directionally solidified samples. To this end, a ZA-27 alloy matrix was reinforced with ceramic particles of SiC and vertically directionally solidified. The cooling rates, temperature gradients, and interphase velocities were then measured, and their influence on the solidification microstructure of the MMCs was analyzed. The recalescence detected and measured during the equiaxed transition was of the order of 3.5°C to 1.1°C. The values of the temperature gradients reached a minimum during the CET and were even negative in most cases (between −3.89 K and 0.06 K. The interphase velocities varied between 0.07 mm/s and 0.44 mm/s at the transition. Also, the presence of ceramic particles in ZA-27 alloys affected the thermodynamic local conditions and the kinetics of nucleation, producing a finer microstructure.

  20. Optical trapping, driving, and arrangement of particles using a tapered fibre probe.

    Science.gov (United States)

    Xin, Hongbao; Xu, Rui; Li, Baojun

    2012-01-01

    The ability of manipulating mesoscopic objects with high precision and flexibility is extremely important for a wide variety of fields from physics, biochemistry, to biomedicine. Particularly, the ability of arranging particles/cells into desired patterns precisely is a challenge for numerous physical and biological applications. Here, we report a strategy of realizing highly flexible trapping, driving, and precise arrangement of particles using a tapered fibre probe. Using randomly distributed 3-µm-diameter silica particles as an example, we demonstrate that the strategy is able to stably trap the particles and drive them to targeted regions, subsequently arrange the particles into desired patterns. To further demonstrate the ability of this strategy, experiments were done using sub-micron sized particles and biological samples (bacteria and cells). This strategy provides a new approach to manipulate mesoscopic objects precisely and flexibly, and hopefully can be used in future fundamental and applied researches of interdiscipline.

  1. Optical trapping, driving, and arrangement of particles using a tapered fibre probe

    Science.gov (United States)

    Xin, Hongbao; Xu, Rui; Li, Baojun

    2012-11-01

    The ability of manipulating mesoscopic objects with high precision and flexibility is extremely important for a wide variety of fields from physics, biochemistry, to biomedicine. Particularly, the ability of arranging particles/cells into desired patterns precisely is a challenge for numerous physical and biological applications. Here, we report a strategy of realizing highly flexible trapping, driving, and precise arrangement of particles using a tapered fibre probe. Using randomly distributed 3-µm-diameter silica particles as an example, we demonstrate that the strategy is able to stably trap the particles and drive them to targeted regions, subsequently arrange the particles into desired patterns. To further demonstrate the ability of this strategy, experiments were done using sub-micron sized particles and biological samples (bacteria and cells). This strategy provides a new approach to manipulate mesoscopic objects precisely and flexibly, and hopefully can be used in future fundamental and applied researches of interdiscipline.

  2. Thermal annealing behavior of nano-size metal-oxide particles synthesized by ion implantation in Fe-Cr alloy

    Science.gov (United States)

    Zheng, C.; Gentils, A.; Ribis, J.; Borodin, V. A.; Descoins, M.; Mangelinck, D.; Dalle, F.; Arnal, B.; Delauche, L.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are promising structural materials for the next generation nuclear reactors, as well as fusion facilities. The detailed understanding of the mechanisms involved in the precipitation of nano-oxides during ODS steel production would strongly contribute to the improvement of the mechanical properties and the optimization of manufacturing of ODS steels, with a potentially strong economic impact for their industrialization. A useful tool for the experimental study of nano-oxide precipitation is ion implantation, a technique that is widely used to synthesize precipitate nanostructures in well-controlled conditions. Earlier, we have demonstrated the feasibility of synthesizing aluminum-oxide particles in the high purity Fe-10Cr alloy by consecutive implantation with Al and O ions at room temperature. This paper describes the effects of high-temperature annealing after the ion implantation stage on the development of the aluminum based oxide nanoparticle system. Using transmission electron microscopy and atom probe tomography experiments, we demonstrate that post-implantation heat treatment induces the growth of the nano-sized oxides in the implanted region and nucleation of new oxide precipitates behind the implantation zone as a result of the diffusion driven broadening of implant profiles. A tentative scenario for the development of metal-oxide nano-particles at both ion implantation and heat treatment stages is suggested based on the experimental observations.

  3. Cardiovascular effects in rats after intratracheal instillation of metal welding particles.

    Science.gov (United States)

    Zheng, Wen; Antonini, James M; Lin, Yen-Chang; Roberts, Jenny R; Kashon, Michael L; Castranova, Vincent; Kan, Hong

    2015-01-01

    Studies have indicated that pulmonary exposure to welding fumes can induce a series of adverse effects in the respiratory system, including infection, bronchitis, siderosis and decreased pulmonary function. Recent clinical and epidemiological studies have found that pulmonary exposure to welding fumes is also associated with a higher incidence of cardiovascular events. However, there is insufficient evidence to confirm a direct effect of welding fumes on the cardiovascular system. The present study investigated the effects of pulmonary exposure to welding fumes on the heart and the vascular system in rats. Two chemically distinct welding fumes generated from manual metal arc-hard surfacing (MMA-HS) and gas metal arc-mild steel (GMA-MS) welding were tested. Three groups of rats were instilled intratracheally with MMA-HS (2 mg/rat), GMA-MS (2 mg/rat) or saline as control once a week for seven weeks. On days 1 and 7 after the last treatment, basal cardiovascular function and the cardiovascular response to increasing doses of adrenoreceptor agonists were assessed. MMA-HS treatment reduced the basal levels of left ventricle end-systolic pressure and dP/dt(max) at 1 day post-treatment, and decreased dP/dt(min) in response to isoproterenol (ISO) at 7 days post-treatment. Unlike MMA-HS, GMA-MS only affected left ventricular end-diastolic pressure in response to ISO at 7 days post-treatment. Treatment with MMA-HS or GMA-MS did not alter heart rate and blood pressure. Our findings suggest that exposure to different welding fumes can induce different adverse effects on the cardiovascular system, and that cardiac contractility may be a sensitive indicator of cardiovascular dysfunction.

  4. High Velocity Impact Interaction of Metal Particles with Porous Heterogeneous Materials with an Inorganic Matrix

    Science.gov (United States)

    Glazunov, A. A.; Ishchenko, A. N.; Afanasyeva, S. A.; Belov, N. N.; Burkin, V. V.; Rogaev, K. S.; Tabachenko, A. N.; Khabibulin, M. V.; Yugov, N. T.

    2016-03-01

    A computational-experimental investigation of stress-strain state and fracture of a porous heterogeneous material with an inorganic matrix, used as a thermal barrier coating of flying vehicles, under conditions of a high-velocity impact by a spherical steel projectile imitating a meteorite particle is discussed. Ballistic tests are performed at the velocities about 2.5 km/s. Numerical modeling of the high-velocity impact is described within the framework of a porous elastoplastic model including fracture and different phase states of the materials. The calculations are performed using the Euler and Lagrange numerical techniques for the velocities up to 10 km/s in a complete-space problem statement.

  5. Analysis of Unequal Electric Field by Moving Metal Particle in GIS Using SNM

    Energy Technology Data Exchange (ETDEWEB)

    Park, K.S. [Hyosung Corporation, Changwon (Korea); Choi, S.Y.; Ko, Y.H. [Chonbuk National University, Chonju (Korea)

    2002-02-01

    In compared with air insulated switchgear, GIS has a high efficiency and confidence. Insulation method using SF{sub 6} gas has a very excellent insulation characteristic for high voltage equipment but has a characteristic that insulation heredity is changed for internal unequal electric field. So analysis of time varying electromagnetic field in GIS is very important for structure design and trouble diagnosis process. In compared with established method, the SNM(Spatial Network Method) in this paper can observe variation of electromagnetic field with real time and get result very similar to measurement. In order to know variation of electromagnetic field distribution in fast moving particle, we make used of SNM. (author). 15 refs., 9 figs.

  6. Study of a ;hot; particle with a matrix of U-bearing metallic Zr: Clue to supercriticality during the Chernobyl nuclear accident

    Science.gov (United States)

    Pöml, P.; Burakov, B.

    2017-05-01

    This paper is dedicated to the 30th anniversary of the severe nuclear accident that occurred at the Chernobyl NPP on 26 April 1986. A detailed study on a Chernobyl ;hot; particle collected from contaminated soil was performed. Optical and electron microscopy, as well as quantitative x-ray microbeam analysis methods were used to determine the properties of the sample. The results show that the particle (≈ 240 x 165 μm) consists of a metallic Zr matrix containing 2-3 wt. % U and bearing veins of an U,Nb admixture. The metallic Zr matrix contains two phases with different amounts of O with the atomic proportions (U,Zr,Nb)0.73O0.27 and (U,Zr,Nb)0.61O0.39. The results confirm the interaction between UO2 fuel and zircaloy cladding in the reactor core. To explain the process of formation of the particle, its properties are compared to laboratory experiments. Because of the metallic nature of the particle it is concluded that it must have formed during a very high temperature (> 2400∘C) process that lasted for only a very short time (few microseconds or less); otherwise the particle should have been oxidised. Such a rapid very high temperature process indicates that at least part of the reactor core could have been supercritical prior to an explosion as it was previously suggested in the literature.

  7. Apply Woods model in the predictions of ambient air particles and metallic elements (Mn, Fe, Zn, Cr, and Cu) at industrial, suburban/coastal, and residential sampling sites.

    Science.gov (United States)

    Fang, Guor-Cheng; Huang, Ci-Song

    2012-01-01

    The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, and Cu) in total suspended particulates (TSPs) concentration, dry deposition at three characteristic sampling sites of central Taiwan. Additionally, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements were calculated with Woods models at these three characteristic sampling sites during years of 2009-2010. As for ambient air particles, the results indicated that the Woods model generated the most accurate dry deposition prediction results when particle size was 18 μm in this study. The results also indicated that the Woods model exhibited better dry deposition prediction performance when the particle size was greater than 10 μm for the ambient air metallic elements in this study. Finally, as for Quan-xing sampling site, the main sources were many industrial factories under process around these regions and were severely polluted areas. In addition, the highest average dry deposition for Mn, Fe, Zn, and Cu species occurred at Bei-shi sampling site, and the main sources were the nearby science park, fossil fuel combustion, and Taichung thermal power plant (TTPP). Additionally, as for He-mei sampling site, the main sources were subjected to traffic mobile emissions.

  8. Fabrication and Mechanical Behavior of Ex Situ Mg-Based Bulk Metallic Glass Matrix Composite Reinforced with Electroless Cu-Coated SiC Particles

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2017-11-01

    Full Text Available Magnesium-based bulk metallic glass matrix composites (BMGMCs have better plasticity than the corresponding bulk metallic glasses (BMGs; however, their strength and density are often compromised due to the fact that the effective reinforcement phase is mostly plastic heavy metal. For lightweight SiC-particle reinforced BMGMCs, interface wettability and the sharpness of the particles often reduce the strengthening effect. In this work, SiC particles were coated with a thin Cu coating by electroless plating, and added to Mg54Cu26.5Ag8.5Gd11 melt in an amount of 5 wt % to prepare a BMGMC. The microstructure of the interface, mechanical behavior and fracture morphology of the BMGMC were studied by scanning electron microscopy and quasi-static compression testing. The results showed that the Cu coating improved the wettability between SiC and the matrix alloy without obvious interfacial reactions, leading to the dispersion of SiC particles in the matrix. The addition of Cu-coated SiC particles improved the plastic deformation ability of Mg54Cu26.5Ag8.5Gd11 BMG, proving that electroless plating was an effective method for controlling the interface microstructure and mechanical behavior of BMGMCs.

  9. Particle impact on metal substrates with application to foreign object damage to aircraft engines

    Science.gov (United States)

    Chen, Xi; Hutchinson, John W.

    2002-12-01

    Foreign object damage (FOD) occurs when hard, millimeter-sized objects such as gravel or sand are ingested into aircraft jet engines. Particles impacting turbine blades at velocities up to about 300 m/ s produce small indentation craters which can become sites for fatigue crack initiation, severely limiting the lifetime of the blade. A framework for analyzing FOD and its effect on fatigue cracking is established in this paper. Finite element analysis is used to determine the residual stresses and geometric stress concentration resulting from FOD. The roles of material rate sensitivity and inertia are delineated. The most important non-dimensional parameters governing impact indents are identified, significantly reducing the set of independent parameters. The second step in the analysis focuses on the potency of cracks emerging from critical locations at the indents. The results have been used to address the question: When and to what extent do the residual stresses and stress concentration caused by FOD reduce the critical crack size associated with threshold fatigue crack growth? For deep indents, it is found that elastic stress concentration is the dominant factor in reducing critical crack threshold when the applied cyclic load ratio, R, is large, otherwise the residual stresses are also important. Comparisons with a set of experiments conducted in parallel with the theory show that the numerical approach can account for various phenomena observed in practice.

  10. Investigation of Effect of Graphite Particles on Drillability of Metal Matrix Composite

    Directory of Open Access Journals (Sweden)

    Saravanakumar ARUNACHALAM

    2016-09-01

    Full Text Available The present article investigates the effect of graphite particles in the drilling of hybrid aluminium matrix composites (AMCs using TiN coated carbide drills. Materials used for the present investigation are Al6063-aluminum alloy reinforced with alumina of size 20 microns and graphite of an average size 75 microns, which are produced through stir casting method. Experiments are conducted based on Taguchi’s method L27 orthogonal array on a vertical machining centre. A model is developed to correlate the drilling parameters with burr height and surface roughness using regression analysis. The results indicate that the developed model is suitable for prediction of burr height and surface roughness in drilling of hybrid AMCs.The influence of different parameters on Surface roughness and burr height of Al6063/Al2O3p/Grp composites has been analyzed through ANOVA table and contour graphs.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.9724

  11. Gas to particle conversion-gas exchange technique for direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Nishiguchi, Kohei; Utani, Keisuke; Gunther, Detlef; Ohata, Masaki

    2014-10-21

    A novel gas to particle conversion-gas exchange technique for the direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry (ICPMS) was proposed and demonstrated in the present study. The technique is based on a transfer of gas into particle, which can be directly analyzed by ICPMS. Particles from metal carbonyl gases such as Cr(CO)6, Mo(CO)6, and W(CO)6 are formed by reaction with ozone (O3) and ammonium (NH3) gases within a newly developed gas to particle conversion device (GPD). The reaction mechanism of the gas to particle conversion is based on either oxidation of metal carbonyl gas by O3 or agglomeration of metal oxide with ammonium nitrate (NH4NO3) which is generated by the reaction of O3 and NH3. To separate the reaction gases (remaining O3 and NH3) from the formed particles, a previously reported gas exchange device (GED) was used and the in argon stabilized analyte particles were directly introduced and measured by ICPMS. This new technique provided limits of detection (LOD) of 0.15 pL L(-1) (0.32 ng m(-3)), 0.02 pL L(-1) (0.07 ng m(-3)), and 0.01 pL L(-1) (0.07 ng m(-3)) for Cr(CO)6, Mo(CO)6, and W(CO)6, respectively, which were 4-5 orders of magnitude lower than those conventional applied for detecting these gases, e.g., gas chromatography with electron captured detector (GC-ECD) as well as Fourier transform-infrared spectroscopy (FT-IR). The achieved LODs were also similar or slightly better than those for ICPMS coupled to GC. Since the gas to particle conversion technique can achieve the direct measurement of metal carbonyl gases as well as the removal of reaction and ambient gases from metal carbonyl gases, the technique is considered to be well suited to monitor gas quality in semiconductor industry, engine exhaust gases, and or waste incineration products.

  12. Timing Challenges for Very Deep Sub-Micron (VDSM IC

    Directory of Open Access Journals (Sweden)

    Ichiang Lin

    2002-01-01

    Full Text Available Many IC design houses failed to be market leaders because they miss the market window due to timing closure problems. Compared to half-micron designs, the amount of time spent on timing verification has greatly increased. Cell delays can be accurately estimated during logic synthesis. However, interconnect delays are unknown until the wire geometry is defined in physical design. Logic synthesis using the cell library models for interconnect delay estimates may be statistically accurate, but can not predict the delay of individual nets accurately. Delay estimates for individual nets (global nets, long wires, large fan-outs, buses, which matter most for the critical paths can be inaccurate and cause a design failure. Inaccurate timing verification causes silicon failure in shipped products that results in the loss of millions of dollars spent designing a high-performance product and potentially larger costs due to lost market share. Full-chip, sign-off verification with silicon-accuracy will allow these problems to be discovered and fixed before tape-out.

  13. Dynamics of vortex matter in YBCO sub-micron bridges

    Science.gov (United States)

    Papari, G.; Carillo, F.; Stornaiuolo, D.; Massarotti, D.; Longobardi, L.; Beltram, F.; Tafuri, F.

    2014-11-01

    We have developed a fabrication process that allows us to realize pure YBCO nanowires displaying robust superconductivity at widths w as low as 160 nm. We can modify the process in order to maintain a Au protective layer. This allows us to scale our nanowires even further to widths as low as 50 nm. We have studied how the presence of vortices and the occurrence of phase slips affect the transport properties of nanowires in the width range ξ entry barrier is found to scale with the width. Our findings confirm that for widths ξ < w < λ nanowires are better protected against phase slips and vortex flow.

  14. Sub-micron surface plasmon resonance sensor systems

    Science.gov (United States)

    Glazier, James A. (Inventor); Amarie, Dragos (Inventor)

    2013-01-01

    Wearable or implantable devices combining microfluidic control of sample and reagent flow and micro-cavity surface plasmon resonance sensors functionalized with surface treatments or coatings capable of specifically binding to target analytes, ligands, or molecules in a bodily fluid are provided. The devices can be used to determine the presence and concentration of target analytes in the bodily fluids and thereby help diagnose, monitor or detect changes in disease conditions.

  15. W-CMP for sub-micron inverse metallisation

    NARCIS (Netherlands)

    van Kranenburg, H.; van Corbach, H.D.; Woerlee, P.H.; Lohmeier, Martin

    1997-01-01

    Chemical Mechanical Polishing (CMP) of tungsten for an inverse metallisation scheme is investigated. The influence of CMP parameters on removal rate and uniformity is studied. The main effects on the removal rate are the applied pressure and the rotation rate of the polishing pad. To the first order

  16. Sub-micron surface plasmon resonance sensor systems

    Science.gov (United States)

    Glazier, James A. (Inventor); Amarie, Dragos (Inventor)

    2012-01-01

    A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprising a light transmissive substrate on which an array of surface plasmon resonant (SPR) elements is mounted is described. A multi-channel sensor for detecting the presence of several targets with a single microchip sensor is described. A multi-channel sensor including collections of SPR elements which are commonly functionalized to one of several targets is also described. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets.

  17. Metrology of sub-micron structured polymer surfaces

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Tosello, Guido; Salaga, J.

    surface replication of the tool insert component when moulding the polymer melt [1]. This aspect is particularly critical when dealing with increasingly small dimensional scales in micro- and nano-structured surfaces [2, 3].In this context, a metrological investigation of polymer replicated surfaces using...

  18. Sub-Micron Grinding of a Food Product

    NARCIS (Netherlands)

    Hennart, S.L.A.

    2011-01-01

    This thesis describes how the activity of a preservative product used in food coatings can be optimized. This project is partly sponsored by the European Marie Curie Framework projects as part of the BioPowders research training network. DSM Food Specialties hosts and co finances this project. The

  19. Metal forming technology for the fabrication of seamless Superconducting radiofrequency cavities for particle accelerators

    Directory of Open Access Journals (Sweden)

    Palmieri Vincenzo

    2015-01-01

    Full Text Available The world of Particle accelerators is rather unique, since in a few high-energy Physics great laboratories, such at CERN for example, there have been built the largest technological installations ever conceived by humankind. The Radiofrequency resonant cavities are the pulsing heart of an accelerator. In case of superconducting accelerators, bulk niobium cavities, able to perform accelerating gradients up to 40 MeV/m, are just a jewel of modern technology. The standard fabrication technology foresees the cutting of circular blanks, their deep-drawing into half-cells, and its further joining by electron beam welding under ultra high vacuum environment that takes several hours. However, proposals such as the International Linear Collider, to which more than 900 scientists from all over the world participate, foresee the installation of 20.000 cavities. In numbers, it means the electron beam weld one by one under Ultra High Vacuum of 360,000 hemi-cells. At a cost of 500 €/Kg of high purity Niobium, this will mean a couple of hundreds of millions of Euros only for the bare material. In this panorama it is evident that a cost reducing approach must be considered. In alternative the author has proposed a seamless and low cost fabrication method based on spinning of fully resonators. Preliminary RF tests at low temperatures have proved that high accelerating gradients are achievable and that they are not worse than those obtainable with the standard technology. Nevertheless up to when the next accelerator will be decided to be built there is still room for improvement.

  20. Modifying magnetic properties and dispersity of few-layer MoS{sub 2} particles by 3d metal carboxylate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Golub, Alexandre S., E-mail: golub@ineos.ac.ru [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow (Russian Federation); Lenenko, Natalia D. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow (Russian Federation); Zaikovskii, Vladimir I. [Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Lavrentieva Ave. 5, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova St. 2, 630090 Novosibirsk (Russian Federation); Efimov, Nikolay N.; Dobrokhotova, Zhanna V.; Baranchikov, Alexander E.; Kiskin, Mikhail A. [N.S. Kurnakov Institute of General and Inorganic Chemistry, Leninskii Prosp. 31, 119991 Moscow (Russian Federation); Eremenko, Igor L. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow (Russian Federation); N.S. Kurnakov Institute of General and Inorganic Chemistry, Leninskii Prosp. 31, 119991 Moscow (Russian Federation)

    2016-11-01

    The interaction of MoS{sub 2} sheets produced by chemical exfoliation of LiMoS{sub 2} in liquid media with trinuclear metal carboxylate complexes of the general formula [M{sub 3}(O{sub 2}CR){sub 6}L{sub 3}]{sup n+} (M = Fe, Co; R = CH{sub 3}, C(CH{sub 3}){sub 3}, CH{sub 2}N{sup +}(CH{sub 3}){sub 3}; L = H{sub 2}O or pyridine) was studied. The composition, structure and dispersity of the obtained materials as well as the distribution of magnetically active metal cations within their particles were analyzed on the basis of PXRD, SEM, TEM, HAADF-STEM, TGA-MS and magnetic measurements data. The interaction process was found to result in the displacement of the important part of carboxylate ligands from coordination environment of metal ions and formation of metal oxide-like nanoclusters. These nanoclusters are distributed within the surface of MoS{sub 2} sheet packets of the thickness of 4–6 nm, which are formed due to restacking of exfoliated MoS{sub 2}. The metal complexes strongly influence sheet restacking, leading to a significantly lower (up to ∼ 1.5 times) thickness of the sulfide packets than in their absence. The metal atoms constituting oxide nanoclusters exhibit strong antiferromagnetic interactions. - Highlights: • MoS{sub 2} sheets interaction with Fe(Co) carboxylate complexes leads to deposition of metal oxide-like clusters on these sheets. • MoS{sub 2} sheet stacking in the presence of metal complexes yields 4–6 nm thick particles. • The metal atoms constituting deposited nanoclusters exhibit strong antiferromagnetic interactions.

  1. Particle size distribution and morphological changes in activated carbon-metal oxide hybrid catalysts prepared under different heating conditions.

    Science.gov (United States)

    Barroso-Bogeat, A; Alexandre-Franco, M; Fernández-González, C; Gómez-Serrano, V

    2016-03-01

    In catalysis processes, activated carbon (AC) and metal oxides (MOs) are widely used either as catalysts or as catalyst supports because of their unique properties. A combination of AC and a MO in a single hybrid material entails changes not only in the composition, microstructure and texture but also in the morphology, which may largely influence the catalytic behaviour of the resulting product. This work is aimed at investigating the modifications in the morphology and particle size distribution (PSD) for AC-MO hybrid catalysts as a result of their preparation under markedly different heating conditions. From a commercial AC and six MO (Al2O3, Fe2O3, ZnO, SnO2, TiO2 and WO3) precursors, two series of such catalysts are prepared by wet impregnation, oven-drying at 120 ºC, and subsequent heat treatment at 200 ºC or 850 ºC in inert atmosphere. The resulting samples are characterized in terms of their morphology and PSD by scanning electron microscopy and ImageJ processing program. Obtained results indicate that the morphology, PSD and degree of dispersion of the supported catalysts are strongly dependent both on the MO precursor and the heat treatment temperature. With the temperature rise, trends are towards the improvement of crystallinity, the broadening of the PSD and the increase in the average particle size, thus suggesting the involvement of sintering mechanisms. Such effects are more pronounced for the Fe, Sn and W catalysts due to the reduction of the corresponding MOs by AC during the heat treatment at 850 ºC. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  2. A Random-Walk-Model for heavy metal particles in natural waters; Ein Random-Walk-Modell fuer Schwermetallpartikel in natuerlichen Gewaessern

    Energy Technology Data Exchange (ETDEWEB)

    Wollschlaeger, A.

    1996-12-31

    The presented particle tracking model is for the numerical calculation of heavy metal transport in natural waters. The Navier-Stokes-Equations are solved with the Finite-Element-Method. The advective movement of the particles is interpolated from the velocities on the discrete mesh. The influence of turbulence is simulated with a Random-Walk-Model where particles are distributed due to a given probability function. Both parts are added and lead to the new particle position. The characteristics of the heavy metals are assigned to the particules as their attributes. Dissolved heavy metals are transported only by the flow. Heavy metals which are bound to particulate matter have an additional settling velocity. The sorption and the remobilization processes are approximated through a probability law which maintains the proportionality ratio between dissolved heavy metals and those which are bound to particulate matter. At the bed heavy metals bound to particulate matter are subjected to deposition and erosion processes. The model treats these processes by considering the absorption intensity of the heavy metals to the bottom sediments. Calculations of the Weser estuary show that the particle tracking model allows the simulation of the heavy metal behaviour even under complex flow conditions. (orig.) [Deutsch] Das vorgestellte Partikelmodell dient zur numerischen Berechnung des Schwermetalltransports in natuerlichen Gewaessern. Die Navier-Stokes-Gleichungen werden mit der Methode der Finiten Elemente geloest. Die advektive Bewegung der Teilchen ergibt sich aus der Interpolation der Geschwindigkeiten auf dem diskreten Netz. Der Einfluss der Turbulenz wird mit einem Random-Walk-Modell simuliert, bei dem sich die Partikel anhand einer vorgegebenen Wahrscheinlichkeitsfunktion verteilen. Beide Bewegungsanteile werden zusammengefasst und ergeben die neue Partikelposition. Die Eigenschaften der Schwermetalle werden den Partikeln als Attribute zugeordnet. Geloeste Schwermetalle

  3. Cherenkov and parametric (quasi-Cherenkov) radiation from relativistic charged particles moving in crystals formed by metallic wires

    CERN Document Server

    Baryshevsky, Vladimir

    2016-01-01

    Until recently, the interaction of electromagnetic waves with crystals built from parallel metallic wires (wire media) was analyzed in the approximation of isotropic scattering of the electromagnetic wave by a single wire. However, if the wires are thick (kR~1), electromagnetic wave scattering by a wire is anisotropic, i.e., the scattering amplitude depends on the scattering angle. In this work, we derive the equations that describe diffraction of electromagnetic waves and spontaneous emission of charged particles in wire media, and take into account the angular dependence of scattering amplitude. Numerical solutions of these equations show that the radiation intensity increases as the wire radius is increased and achieves its maximal value in the range kR~1. The case when the condition kR~1 is fulfilled in the THz frequency range is considered in detail. The calculations show that the instantaneous power of Cherenkov and parametric (quasi-Cherenkov) radiations from electron bunches in the crystal can be tens...

  4. 40 CFR Appendix A to Subpart Uuu... - Determination of Metal Concentration on Catalyst Particles (Instrumental Analyzer Procedure)

    Science.gov (United States)

    2010-07-01

    ... Catalyst Particles (Instrumental Analyzer Procedure) A Appendix A to Subpart UUU of Part 63 Protection of... Concentration on Catalyst Particles (Instrumental Analyzer Procedure) 1.0Scope and Application. 1.1Analytes. The... concentrations on catalyst particles. This method is applicable for catalyst particles obtained from the fluid...

  5. Three-dimensional Hierarchical Metal oxide-Carbon Electrode Material for High Efficient Microbial Electrosynthesis

    DEFF Research Database (Denmark)

    Cui, Mengmeng; Nie, Huarong; Zhang, Tian

    2017-01-01

    pore structure in a microwave oven is demonstrated. Microwave pyrolysis of ferrocene using carbon felt as a microwave absorber, a method that is rapid (tens of seconds), does not require harsh conditions nor costly equipment is utilized, and can be readily scaled up. The produced material has a high......The production of hierarchical hybrid conductive materials that are mesoporous, with pores spanning from sub-micron to microns in size, is important for large-area electrode applications. Here, a simple one-step, low-cost method to fabricate a metal oxide-carbon hybrid materials with a hierarchical...

  6. Role of plant growth promoting rhizobacteria and Ag-nano particle in the bioremediation of heavy metals and maize growth under municipal wastewater irrigation.

    Science.gov (United States)

    Khan, Naeem; Bano, Asghari

    2016-01-01

    The investigation evaluated the role of plant growth promoting rhizobacteria (PGPR) and Ag-nano particle on the growth and metabolism of maize irrigated with municipal wastewater (MW). Three PGPR isolated from MW were identified on the basis of 16S-rRNA gene sequence analyses as Pseudomonas sp., Pseudomonas fluorescence, and Bacillus cereus. The municipal waste water was used to irrigate the maize seeds inoculated with 3 isolated PGPR. The isolated PGPR had catalase and oxidase enzymes, solubilize insoluble bound phosphate and exhibit antifungal and antibacterial activities. The colony forming unit (cfu) of the PGPR was inhibited by Ag-nano particle, but was stimulated by the municipal wastewater. The Ag-nano particles augmented the PGPR induced increase in root area and root length. The root-shoot ratio was also changed with the Ag-nano particles. The plants irrigated with municipal wastewater had higher activities of peroxidase and catalase which were further augmented by Ag-nano particle. The Ag- nano particle application modulated level of ABA (34%), IAA (55%), and GA (82%), increased proline production (70%) and encountered oxidative stress and augmented the bioremediation potential of PGPR for Pb, Cd, and Ni. Municipal wastewater needs to be treated with PGPR and Ag nano particle prior to be used for irrigation. This aims for the better growth of the plant and enhanced bioremediation of toxic heavy metals.

  7. Study of the heavy metals speciation in the atmospheric suspended particles in Sevilla (Spain); Estudio de la especiacion de metales pesados en la materia particulada atmosferica de la ciudad de Sevilla

    Energy Technology Data Exchange (ETDEWEB)

    Ternero Rodriguez, M.; Sequeiros Madueno, L.; Jimenez Sanchez, C.; Barragan de la Rosa, J.; Bello Lopez, M.; Fernandez Espinosa, A.J.; Perez Bernal, J.L. [Facultad de Quimica, Universidad de Sevilla (Spain)

    1997-06-01

    This work develops analytical methods for the heavy metals speciation in the atmospheric suspended particles. In base to these methods, we study the atmospheric contamination of the city of Seville, determining the metals Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb. We also study the effects of metallic species in the alteration processes on rocks material, in base to the SO{sub 2}/SO{sub 4}{sup {minus}{minus}}. The project develops in two years: in the first, we develop the methods of chemistry speciation based on the extraction with different reagents and the methods of physical speciation based on the particle size distribution with cascade impactors. Also, we develop the methodology for the environmental simulation of alteration processes, in base to the heterogeneous catalysis, by metallic ions, of the SO{sub 2} on the surface of the stone. In the second year we apply the methods of speciation to the study of the contamination by heavy metals in the city of Seville. This part divides in two phases: a first of the preliminary study in the city in order to identify the different polluting focuses, and a secondary of study of the contamination produced by punctual sources, in the more polluted points of the city. On the other hand, the study of the alteration processes of rock materials has centred on materials employees in monuments of the city and on application of the catalyzers found in the particulate matter of the true environment of the materials. (Author)

  8. Spherical bioactive glass particles and their interaction with human mesenchymal stem cells in vitro.

    Science.gov (United States)

    Labbaf, Sheyda; Tsigkou, Olga; Müller, Karin H; Stevens, Molly M; Porter, Alexandra E; Jones, Julian R

    2011-02-01

    Sub-micron particles of bioactive glass (SMBGs) with composition 85 mol% SiO(2) and 15 mol% CaO were synthesised and characterised. Bioactivity was demonstrated by the formation of calcium apatite following 5 days immersion in simulated body fluid (SBF). The effect of a 24 h exposure of SMBGs (100 μg/ml, 150 μg/ml, 200 μg/ml) to human mesenchymal stem cells (hMSCs) on cell viability, metabolic activity and proliferation were determined using the LIVE/DEAD, MTT, total DNA and LDH assays after 1, 4 and 7 days of culture. None of the SMBG concentrations caused significant cytotoxicity at 1 and 4 days, but the doses of 150 and 200 μg/ml significantly decreased hMSC metabolic activity after 7 days of culture. Cell proliferation decreased as SMBG concentration increased; however none of the SMBGs tested had a significant effect on DNA quantity compared to the control. Confocal microscopy confirmed cellular uptake and localisation of the SMBGs in the hMSC cytoskeleton. Transmission electron microscopy revealed that the SMBGs localised inside the cell cytoplasm and cell endosomes. These findings are important for assessing the toxicity of sub-micron particles that may either be used as injectables for bone regeneration or generated by wear or degradation of bioactive glass scaffolds. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Using SF6 Decomposed Component Analysis for the Diagnosis of Partial Discharge Severity Initiated by Free Metal Particle Defect

    Directory of Open Access Journals (Sweden)

    Ju Tang

    2017-08-01

    Full Text Available The decomposition characteristics of a SF6 gas-insulated medium were used to diagnose the partial discharge (PD severity in DC gas-insulated equipment (DC-GIE. First, the PD characteristics of the whole process were studied from the initial PD to the breakdown initiated by a free metal particle defect. The average discharge magnitude in a second was used to characterize the PD severity and the PD was divided into three levels: mild PD, medium PD, and dangerous PD. Second, two kinds of voltage in each of the above PD levels were selected for the decomposition experiments of SF6. Results show that the negative DC-PD in these six experiments decomposes the SF6 gas and generates five stable decomposed components, namely, CF4, CO2, SO2F2, SOF2, and SO2. The concentrations and concentration ratios of the SF6 decomposed components can be associated with the PD severity. A minimum-redundancy-maximum-relevance (mRMR-based feature selection algorithm was used to sort the concentrations and concentration ratios of the SF6 decomposed components. Back propagation neural network (BPNN and support vector machine (SVM algorithms were used to diagnose the PD severity. The use of C(CO2/CT1, C(CF4/C(SO2, C(CO2/C(SOF2, and C(CF4/C(CO2 shows good performance in diagnosing PD severity. This finding serves as a foundation in using the SF6 decomposed component analysis (DCA method to diagnose the insulation faults in DC-GIE and assess its insulation status.

  10. Wear particles derived from metal hip implants induce the generation of multinucleated giant cells in a 3-dimensional peripheral tissue-equivalent model.

    Directory of Open Access Journals (Sweden)

    Debargh K Dutta

    Full Text Available Multinucleate giant cells (MGCs are formed by the fusion of 5 to 15 monocytes or macrophages. MGCs can be generated by hip implants at the site where the metal surface of the device is in close contact with tissue. MGCs play a critical role in the inflammatory processes associated with adverse events such as aseptic loosening of the prosthetic joints and bone degeneration process called osteolysis. Upon interaction with metal wear particles, endothelial cells upregulate pro-inflammatory cytokines and other factors that enhance a localized immune response. However, the role of endothelial cells in the generation of MGCs has not been completely investigated. We developed a three-dimensional peripheral tissue-equivalent model (PTE consisting of collagen gel, supporting a monolayer of endothelial cells and human peripheral blood mononuclear cells (PBMCs on top, which mimics peripheral tissue under normal physiological conditions. The cultures were incubated for 14 days with Cobalt chromium alloy (CoCr ASTM F75, 1-5 micron wear particles. PBMC were allowed to transit the endothelium and harvested cells were analyzed for MGC generation via flow cytometry. An increase in forward scatter (cell size and in the propidium iodide (PI uptake (DNA intercalating dye was used to identify MGCs. Our results show that endothelial cells induce the generation of MGCs to a level 4 fold higher in 3-dimentional PTE system as compared to traditional 2-dimensional culture plates. Further characterization of MGCs showed upregulated expression of tartrate resistant alkaline phosphatase (TRAP and dendritic cell specific transmembrane protein, (DC-STAMP, which are markers of bone degrading cells called osteoclasts. In sum, we have established a robust and relevant model to examine MGC and osteoclast formation in a tissue like environment using flow cytometry and RT-PCR. With endothelial cells help, we observed a consistent generation of metal wear particle- induced MGCs

  11. Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part II: Importance of physicochemical properties and dose in animal and in vitro studies as a basis for risk assessment.

    Science.gov (United States)

    Madl, Amy K; Kovochich, Michael; Liong, Monty; Finley, Brent L; Paustenbach, Dennis J; Oberdörster, Günter

    2015-07-01

    The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. An improved model for computing the trajectories of conductive particles in roll-type electrostatic separator for recycling metals from WEEE

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jiang; Li Jia [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai (China); Xu Zhenming, E-mail: zmxu@sjtu.edu.cn [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai (China)

    2009-08-15

    Electrostatic separation presents an effective and environmentally friendly way for recycling metals and nonmetals from ground waste electrical and electronic equipment (WEEE). For this process, the trajectory of conductive particle is significant and some models have been established. However, the results of previous researches are limited by some simplifying assumptions and lead to a notable discrepancy between the model prediction and the experimental results. In the present research, a roll-type corona-electrostatic separator and ground printed circuit board (PCB) wastes were used to investigate the trajectory of the conductive particle. Two factors, the air drag force and the different charging situation, were introduced into the improved model. Their effects were analyzed and an improved model for the theoretical trajectory of conductive particle was established. Compared with the previous one, the improved model shows a good agreement with the experimental results. It provides a positive guidance for designing of separator and makes a progress for recycling the metals and nonmetals from WEEE.

  13. An improved model for computing the trajectories of conductive particles in roll-type electrostatic separator for recycling metals from WEEE.

    Science.gov (United States)

    Wu, Jiang; Li, Jia; Xu, Zhenming

    2009-08-15

    Electrostatic separation presents an effective and environmentally friendly way for recycling metals and nonmetals from ground waste electrical and electronic equipment (WEEE). For this process, the trajectory of conductive particle is significant and some models have been established. However, the results of previous researches are limited by some simplifying assumptions and lead to a notable discrepancy between the model prediction and the experimental results. In the present research, a roll-type corona-electrostatic separator and ground printed circuit board (PCB) wastes were used to investigate the trajectory of the conductive particle. Two factors, the air drag force and the different charging situation, were introduced into the improved model. Their effects were analyzed and an improved model for the theoretical trajectory of conductive particle was established. Compared with the previous one, the improved model shows a good agreement with the experimental results. It provides a positive guidance for designing of separator and makes a progress for recycling the metals and nonmetals from WEEE.

  14. Fabrication of metal half-shells using colloidal particle monolayer and their application in surface-enhanced Raman scattering.

    Science.gov (United States)

    Taniguchi, Yuichi; Endo, Hiroshi; Kawai, Takeshi

    2012-01-01

    Three types of Au shells, an isolated half-shell, one-dimensional strings of shells, and two-dimensional films, were fabricated by using a monolayer of polystyrene (PS) particles with diameters of 213, 560, and 1360 nm. The three types of Au shells that were removed from the PS particle monolayer and the as-deposited Au shells that adhered to PS particles were modified with 4-mercaptopyridine for use as platforms for surface-enhanced Raman scattering (SERS). We examined the effects of the shapes and sizes of Au shells on their SERS efficiency and found that the Au shells exhibited strong SERS signals and that Au shells prepared by using 560-nm PS particles were the most suitable platform for SERS at both 632.8- and 785-nm excitations. Further, we found that SERS enhancements depended on the shape of Au shells and on whether Au shells adhered to PS particles or not.

  15. Encapsulation of ZnO particles by metal fluorides: Towards an application as transparent insulating coatings for windows

    Science.gov (United States)

    Trenque, Isabelle; Mornet, Stéphane; Duguet, Etienne; Majimel, Jérôme; Brüll, Annelise; Teinz, Katharina; Kemnitz, Erhard; Gaudon, Manuel

    2013-01-01

    Because ZnO is a promising candidate for getting efficient films or varnishes with thermal insulating abilities for windows applications, the effect of the encapsulation of ZnO particles in shells of low refractive index material on the improvement of the visible light transmission was investigated. ZnO-MgF2 core-shell particles were synthesized by deposition of fluoride sols on ZnO particles through a vacuum slip casting process like. The transmission behaviours were first indirectly studied by diffuse reflexion measurements on powder beds. Then, particle films were elaborated by a screen printing process which ensured direct transmission measurements. The encapsulation of ZnO particles with a coating shell of 1.3 wt.% of MgF2 improves the visible light transmission of 32%.

  16. Potency of (doped) rare earth oxide particles and their constituent metals to inhibit algal growth and induce direct toxic effects.

    Science.gov (United States)

    Joonas, Elise; Aruoja, Villem; Olli, Kalle; Syvertsen-Wiig, Guttorm; Vija, Heiki; Kahru, Anne

    2017-09-01

    Use of rare earth elements (REEs) has increased rapidly in recent decades due to technological advances. It has been accompanied by recurring rare earth element anomalies in water bodies. In this work we (i) studied the effects of eight novel doped and one non-doped rare earth oxide (REO) particles (aimed to be used in solid oxide fuel cells and gas separation membranes) on algae, (ii) quantified the individual adverse effects of the elements that constitute the (doped) REO particles and (iii) attempted to find a discernible pattern to relate REO particle physicochemical characteristics to algal growth inhibitory properties. Green algae Raphidocelis subcapitata (formerly Pseudokirchneriella subcapitata) were used as a test species in two different formats: a standard OECD201 algal growth inhibition assay and the algal viability assay (a 'spot test') that avoids nutrient removal effects. In the 24h 'spot' test that demonstrated direct toxicity, algae were not viable at REE concentrations above 1mgmetal/L. 72-hour algal growth inhibition EC50 values for four REE salts (Ce, Gd, La, Pr) were between 1.2 and 1.4mg/L, whereas the EC50 for REO particles ranged from 1 to 98mg/L. The growth inhibition of REEs was presumably the result of nutrient sequestration from the algal growth medium. The adverse effects of REO particles were at least in part due to the entrapment of algae within particle agglomerates. Adverse effects due to the dissolution of constituent elements from (doped) REO particles and the size or specific surface area of particles were excluded, except for La2NiO4. However, the structure of the particles and/or the varying effects of oxide composition might have played a role in the observed effects. As the production rates of these REO particles are negligible compared to other forms of REEs, there is presumably no acute risk for aquatic unicellular algae. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Particle Imaging, Characterization and Extinction Measurement with Digital Holography

    Science.gov (United States)

    Subedi, Nava; Berg, Matthew

    2015-03-01

    Digital holographic microcopy (DHM) can be a ground breaking technique in the field of particle diagnostic because of its capability for imaging, characterization and extinction measurement in situ. The beauty of this technique is that a single experimental set up is able to do all these works at the same time. In this sense DHM can be used to establish a new kind of instrumentation having the properties of cost-effective, light-weight and portable. Besides this, this technique also has lots of useful applications in the field of aerosol research, climate modeling, life science, polymer crystallization, and defense. We are using DHM for sub-micron sized particle imaging, characterization and extinction. In this work, a particle is illuminated by a pulsed laser and the interference pattern produced by superposition of particle's forward-scattered wave with the incident wave is recorded by a digital camera. The recorded pattern constitutes a digital hologram which can be numerically processed to get image, composition information and extinction cross-section of the particle. These information of the particle are the basic requirements for the characterization of respirable-sized (1-10 μm) aerosols particles.

  18. Cysteine-Functionalized Chitosan Magnetic Nano-Based Particles for the Recovery of Light and Heavy Rare Earth Metals: Uptake Kinetics and Sorption Isotherms.

    Science.gov (United States)

    Galhoum, Ahmed A; Mafhouz, Mohammad G; Abdel-Rehem, Sayed T; Gomaa, Nabawia A; Atia, Asem A; Vincent, Thierry; Guibal, Eric

    2015-02-04

    Cysteine-functionalized chitosan magnetic nano-based particles were synthesized for the sorption of light and heavy rare earth (RE) metal ions (La(III), Nd(III) and Yb(III)). The structural, surface, and magnetic properties of nano-sized sorbent were investigated by elemental analysis, FTIR, XRD, TEM and VSM (vibrating sample magnetometry). Experimental data show that the pseudo second-order rate equation fits the kinetic profiles well, while sorption isotherms are described by the Langmuir model. Thermodynamic constants (ΔG°, ΔH°) demonstrate the spontaneous and endothermic nature of sorption. Yb(III) (heavy RE) was selectively sorbed while light RE metal ions La(III) and Nd(III) were concentrated/enriched in the solution. Cationic species RE(III) in aqueous solution can be adsorbed by the combination of chelating and anion-exchange mechanisms. The sorbent can be efficiently regenerated using acidified thiourea.

  19. Influence of fine process particles enriched with metals and metalloids on Lactuca sativa L. leaf fatty acid composition following air and/or soil-plant field exposure.

    Science.gov (United States)

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

    2013-08-01

    We investigate the effect of both foliar and root uptake of a mixture of metal(loid)s on the fatty acid composition of plant leaves. Our objectives are to determine whether both contamination pathways have a similar effect and whether they interact. Lactuca sativa L. were exposed to fine process particles enriched with metal(loid)s in an industrial area. Data from a first experiment were used to conduct an exploratory statistical analysis which findings were successfully cross-validated by using the data from a second one. Both foliar and root pathways impact plant leaf fatty acid composition and do not interact. Z index (dimensionless quantity), weighted product of fatty acid concentration ratios was built up from the statistical analyses. It provides new insights on the mechanisms involved in metal uptake and phytotoxicity. Plant leaf fatty acid composition is a robust and fruitful approach to detect and understand the effects of metal(loid) contamination on plants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Synthesis of supported metallic nano-particles and their use in air depollution; Des nanoparticules metalliques supportees pour la depollution de l'air

    Energy Technology Data Exchange (ETDEWEB)

    Barrault, J. [Centre National de la Recherche Scientifique (CNRS), 86 - Poitiers (France); Valange, S. [Poitiers Univ., 86 (France); Tatibouet, J.M. [Centre National de la Recherche Scientifique (CNRS), Lab. de Catalyse en Chimie Organique, UMR CNRS 6503, 86 - Poitiers (France); Thollon, St. [CEA Grenoble (DRT/DTNM/LTS), 38 (France); Herlin-Boime, N. [CEA Saclay, IRAMIS, Service des Photons, Atomes et Molecules, Lab. Francis Perrin, CEA-CNRS URA 2453, 91 - Gif-sur-Yvette (France); Giraud, S. [CEA Saclay (DEN/SRMA), 91 - Gif-sur-Yvette (France); Ruiz, J.Ch. [CEA Marcoule (DTCD/SPDE/LFSM), 30 (France); Bergaya, B. [CRT Plasma lASER, 45 - Orleans (France); Joulin, J.P.; Delbianco, N. [Ceramiques Techniques Industrielles (CTI-SA), 30 - Salindres (France); Gabelica, Z. [Universite de Haute-Alsace (LPI-GSEC), ENSCMu, 68 - Mulhouse (France); Daturi, M. [Ecole Nationale Superieure d' Ingenieurs de Caen (ENSICAEN), CNRS-LCS, UMR 6506, 14 - Caen (France)

    2009-06-15

    The main objectives of the 'NACACOMO' Consortium ('Nano-materials: Catalysts for the Conversion of organic Molecules. Uses in fine chemicals and environment protection ') consisted in generating novel catalysts composed of nanoparticles of metals (Pt, Pd, Ag...) and/or oxides (TiO{sub 2}...) stabilized and well distributed over the surface of a support (foams, ceramics), by monitoring both the particle size and the 'coating' process itself, using new technologies: CVD, plasma-spray, laser pyrolysis, supercritical preparation, which were compared to conventional soft chemistry recipes. The most accurate characterization of particle morphology, local structure, texture, spatial arrangement but also of their reactivity, were achieved by privileging the utilization of various in situ methods. Details on formation mechanisms of a solid nano-particle at the atomic level (nucleation, growth and particle (re)distribution over the support...) could be obtained in selected cases, with opportunities for scaling up and shaping. The (chemical) nature of the so-obtained nano-materials was monitored for selected catalytic applications involving the development of environmental friendly processes, such as oxidation of VOC, with a priority for aromatics and chlorinated compounds. (authors)

  1. Development and application of a dosimetry model (ExDoM2) for calculating internal dose of specific particle-bound metals in the human body.

    Science.gov (United States)

    Chalvatzaki, Eleftheria; Lazaridis, Mihalis

    2015-01-01

    The objective of the current study was to develop a dosimetry model (ExDoM2) for calculating internal dose of specific particle-bound metals (As, Pb, Cd, Cr and Mn) in the human body. The ExDoM2 is a revised version of a respiratory tract model (ExDoM) incorporating a new particle clearance mechanism in the respiratory tract model and a Physiologically-Based PharmacoKinetic (PBPK) model. The revised respiratory tract model was used to calculate the deposition, clearance and retention of particles in the human respiratory tract and the mass transferred to the oesophagus (gastrointestinal tract) and blood. The PBPK module was used to analyze the distribution of metals (As, Pb, Cd, Cr and Mn) from the blood circulation system to other organs or tissues like liver, kidneys, heart, brain, muscle and bone. The model was applied to calculate the internal human dose for an adult Caucasian male exposed to particulate mass matter (PM), PMPb, PMCd, PMMn and PMCr in an urban area (Athens, Greece). The analysis showed that at the end of the exposure (one day exposure scenario) to PMPb, the major accumulation occurs in the bone, blood and muscle, whereas as regards PMCd the major accumulation occurs in the other tissues, like kidney and liver. In addition, for PMMn, the major accumulation occurs in the other tissues and lungs, whereas as regards PMCr the major accumulation occurs in the gastrointestinal (GI) tract and lungs. Therefore, ExDoM2 is an important feature in studying deposition of particles in the human body.

  2. CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells

    Energy Technology Data Exchange (ETDEWEB)

    Posada, Olga M., E-mail: O.M.PosadaEstefan@leeds.ac.uk [Biomedical Engineering Department, University of Strathclyde, Wolfson Centre, Glasgow G4 0NW (United Kingdom); Gilmour, Denise [Pure and Applied Chemistry Department, University of Strathclyde, Thomas Graham Building, Glasgow G1 1XL (United Kingdom); Tate, Rothwelle J., E-mail: r.j.tate@strath.ac.uk [Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE (United Kingdom); Grant, M. Helen [Biomedical Engineering Department, University of Strathclyde, Wolfson Centre, Glasgow G4 0NW (United Kingdom)

    2014-11-15

    Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p < 0.05) amounts of Co and Cr ions into the culture medium, and significant (p < 0.05) cellular uptake of both ions. There was also an increase (p < 0.05) in apoptosis after a 48 h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p < 0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions + debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. - Highlights: • Effects of CoCr nanoparticles and Co ions on U937 cells were investigated. • Ions released from wear debris play an important role in cellular response, • Toxicity of Co ions could be related to NO metabolic processes and apoptosis. • CoCr particles were a more effective inducer of apoptosis after cell

  3. Gold particle formation via photoenhanced deposition on lithium niobate

    Science.gov (United States)

    Zaniewski, A. M.; Meeks, V.; Nemanich, R. J.

    2017-05-01

    In this work, we report on a technique to reduce gold chloride into sub-micron particles and nanoparticles. We use photoelectron transfer from periodically polarized lithium niobate (PPLN) illuminated with above band gap light to drive the surface reactions required for the reduction and particle formation. The particle sizes and distributions on the PPLN surface are sensitive to the solution concentration, with inhibited nucleation and large particles (>150 nm) for both low (2E-8M to 9E-7M) and high (1E-5M to 1E-3M) concentrations of gold chloride. At midrange values of the concentration, nucleation is more frequent, resulting in smaller sized particles (<150 nm). We compare the deposition process to that for silver, which has been previously studied. We find that the reduction of gold chloride into nanoparticles is inhibited compared to silver ion reduction, due to the multi-step reaction required for gold particle formation. This also has consequences for the resulting deposition patterns: while silver deposits into nanowires along boundaries between areas with opposite signed polarizations, such patterning of the deposition is not observed for gold, for a wide range of concentrations studied (2E-8 to 1E-3M).

  4. Gold particle formation via photoenhanced deposition on lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Zaniewski, A.M., E-mail: azaniews@asu.edu; Meeks, V.; Nemanich, R.J.

    2017-05-31

    Highlights: • Gold chloride is reduced into solid gold nanoparticles at the surface of a polarized semiconductor. • Reduction processes are driven by ultraviolet light. • Gold nanoparticle and silver nanoparticle deposition patterns are compared. - Abstract: In this work, we report on a technique to reduce gold chloride into sub-micron particles and nanoparticles. We use photoelectron transfer from periodically polarized lithium niobate (PPLN) illuminated with above band gap light to drive the surface reactions required for the reduction and particle formation. The particle sizes and distributions on the PPLN surface are sensitive to the solution concentration, with inhibited nucleation and large particles (>150 nm) for both low (2E−8M to 9E−7M) and high (1E−5M to 1E−3M) concentrations of gold chloride. At midrange values of the concentration, nucleation is more frequent, resulting in smaller sized particles (<150 nm). We compare the deposition process to that for silver, which has been previously studied. We find that the reduction of gold chloride into nanoparticles is inhibited compared to silver ion reduction, due to the multi-step reaction required for gold particle formation. This also has consequences for the resulting deposition patterns: while silver deposits into nanowires along boundaries between areas with opposite signed polarizations, such patterning of the deposition is not observed for gold, for a wide range of concentrations studied (2E−8 to 1E−3M).

  5. Continuous syntheses of Pd@Pt and Cu@Ag core-shell nanoparticles using microwave-assisted core particle formation coupled with galvanic metal displacement

    Science.gov (United States)

    Miyakawa, Masato; Hiyoshi, Norihito; Nishioka, Masateru; Koda, Hidekazu; Sato, Koichi; Miyazawa, Akira; Suzuki, Toshishige M.

    2014-07-01

    Continuous synthesis of Pd@Pt and Cu@Ag core-shell nanoparticles was performed using flow processes including microwave-assisted Pd (or Cu) core-nanoparticle formation followed by galvanic displacement with a Pt (or Ag) shell. The core-shell structure and the nanoparticle size were confirmed using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) observation and EDS elemental mapping. The Pd@Pt nanoparticles with a particle size of 6.5 +/- 0.6 nm and a Pt shell thickness of ca. 0.25 nm were synthesized with appreciably high Pd concentration (Pd 100 mM). This shell thickness corresponds to one atomic layer thickness of Pt encapsulating the Pd core metal. The particle size of core Pd was controlled by tuning the initial concentrations of Na2[PdCl4] and PVP. Core-shell Cu@Ag nanoparticles with a particle size of 90 +/- 35 nm and an Ag shell thickness of ca. 3.5 nm were obtained using similar sequential reactions. Oxidation of the Cu core was suppressed by the coating of Cu nanoparticles with the Ag shell.Continuous synthesis of Pd@Pt and Cu@Ag core-shell nanoparticles was performed using flow processes including microwave-assisted Pd (or Cu) core-nanoparticle formation followed by galvanic displacement with a Pt (or Ag) shell. The core-shell structure and the nanoparticle size were confirmed using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) observation and EDS elemental mapping. The Pd@Pt nanoparticles with a particle size of 6.5 +/- 0.6 nm and a Pt shell thickness of ca. 0.25 nm were synthesized with appreciably high Pd concentration (Pd 100 mM). This shell thickness corresponds to one atomic layer thickness of Pt encapsulating the Pd core metal. The particle size of core Pd was controlled by tuning the initial concentrations of Na2[PdCl4] and PVP. Core-shell Cu@Ag nanoparticles with a particle size of 90 +/- 35 nm and an Ag shell thickness of ca. 3.5 nm were obtained using similar sequential

  6. Parallel nanostructuring of GeSbTe film with particle mask

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.B.; Hong, M.H.; Wang, Q.F.; Chong, T.C. [Data Storage Institute, DSI Building, 5 Engineering Drive 1, 117608, Singapore (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, 119260, Singapore (Singapore); Luk' yanchuk, B.S.; Huang, S.M.; Shi, L.P. [Data Storage Institute, DSI Building, 5 Engineering Drive 1, 117608, Singapore (Singapore)

    2004-09-01

    Parallel nanostructuring of a GeSbTe film may significantly improve the recording performance in data storage. In this paper, a method that permits direct and massively parallel nanopatterning of the substrate surface by laser irradiation is investigated. Polystyrene spherical particles were deposited on the surface in a monolayer array by self-assembly. The array was then irradiated with a 248-nm KrF laser. A sub-micron nanodent array can be obtained after single-pulse irradiation. These nanodents change their shapes at different laser energies. The optical near-field distribution around the particles was calculated according to the exact solution of the light-scattering problem. The influence of the presence of the substrate on the optical near field was also studied. The mechanisms for the generation of the nanodent structures are discussed. (orig.)

  7. Adsorptive separation and photocatalytic degradation of methylene blue dye on titanate nanotube powders prepared by hydrothermal process using metal Ti particles as a precursor.

    Science.gov (United States)

    Hu, Keshui; Xiao, Xin; Cao, Xiufang; Hao, Rong; Zuo, Xiaoxi; Zhang, Xiaojing; Nan, Junmin

    2011-08-30

    Titanate nanotube powders (TNTPs) with the twofold removal ability, i.e. adsorptive separation and photocatalytic degradation, are synthesized under hydrothermal conditions using metal Ti particles as a precursor in the concentrated alkaline solution, and their morphology, structure, adsorptive and photocatalytic properties are investigated. Under hydrothermal conditions, the titanate nanotubes (TNTs) with pore diameter of 3-4nm are produced on the surface of metal Ti particles, and stacked together to form three-dimensional (3D) network with porous structure. The TNTPs synthesized in the autoclave at 130°C for 24h exhibits a maximum adsorption capability of about 197mg g(-1) in the neutral methylene blue (MB) solution (40mg L(-1)) within 90min, the adsorption process can be described by pseudo second-order kinetics model. Especially, in comparison with the adsorptive and the photocatalytic processes are performed in turn, about 50min can be saved through synchronously utilizing the double removal ability of TNTPs when the removal ratio of MB approaches 95% in MB solution (40mg L(-1)) at a solid-liquid (S/L) ratio of 1:8 under ultraviolet (UV) light irradiation. These 3D TNTPs with the twofold removal properties and easier separation ability for recycling use show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. The Influence of Coating Oxide Metal on Surface of SiC Particles to Elastic Modulus of Al/SiC Composites

    Directory of Open Access Journals (Sweden)

    Dedi Priadi

    2008-11-01

    Full Text Available The isotropic composites of Al/SiC is made by powder metallurgy method, the quality of mechanical materials depend on interfacial bonding between matrix (Al and reinforcement (SiC. The quality of interfacial bonding can influence to elastic modulus of composites which is made by solid process. SiC particles were coated by metal oxide aim to enhance quality interfacial bonding between matrix and reinforcement. These research using three kinds of coating materials, which are Mg oxide, Cu oxide and Al oxide, and these materials were deposited on surface of SiC particles. From three kinds of materials coating Al2O3 is the best to enhance quality interfacial bonding between matrix and reinforce than the others as CuO or MgO. There is Intermetalic phase formatted on CuO coating, and MgO coating have many porous where they can make decrease quality of Al-SiC composites. All of volume fraction of SiC on the Al/SiC composites, which oxide aluminum coating on SiC surface have highest value of elastic modulus than the others metal oxides.

  9. Particle variations and effect on the microstructure and microhardness of Ti6al4V hybrid metal matrix system

    CSIR Research Space (South Africa)

    Akinlabi, ET

    2017-01-01

    Full Text Available was investigated. The hardness value improved significantly in the following order. 971.1 HV0.5, 971.1 HV0.5 and 1161.8 HV0.5 respectively. The overall coatings of layers were characterized by good microstructural homogeneity, excellent bonding with a metal...

  10. Power handling of a liquid-metal based CPS structure under high steady-state heat and particle fluxes

    NARCIS (Netherlands)

    Morgan, T. W.; Vertkov, A.; Bystrov, K.; Lyublinski, I.; Genuit, J. W.; Mazzitelli, G.

    2017-01-01

    Liquid metal infused capillary porous structures (CPSs) are considered as a potential divertor solution for DEMO due to their potential power handling capability and resilience to long term damage. In this work the power handling and performance of such Sn-based CPS systems is assessed both

  11. Particle-bound metal transport after removal of a small dam in the Pawtuxet River, Rhode Island, USA

    Science.gov (United States)

    The Pawtuxet River in Rhode Island, USA, has a long history of industrial activity and pollutant discharges. Metal contamination of the river sediments is well documented and historically exceeded toxicity thresholds for a variety of organisms. The Pawtuxet River dam, a low-head ...

  12. Independent control of metal cluster and ceramic particle characteristics during one-step synthesis of Pt/TiO2

    DEFF Research Database (Denmark)

    Schulz, H.; Madler, L.; Strobel, R.

    2005-01-01

    Rapid quenching during flame spray synthesis of Pt/TiO2 (0-10 Wt% Pt) is demonstrated as a versatile method for independent control of support (TiO2) and noble metal (Pt)cluster characteristics. Titania grain size, morphology, crystal phase structure, and crystal size were analyzed by nitrogen...

  13. A new strategy on utilizing nitrogen doped TiO{sub 2} in nanostructured solar cells: Embedded multifunctional N-TiO{sub 2} scattering particles in mesoporous photoanode

    Energy Technology Data Exchange (ETDEWEB)

    Shogh, Shiva [Department of Physics, Sharif University of Technology, Tehran 11365-9161 (Iran, Islamic Republic of); Mohammadpour, Raheleh [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran 14588-89694 (Iran, Islamic Republic of); Iraji zad, Azam, E-mail: Iraji@sharif.edu [Department of Physics, Sharif University of Technology, Tehran 11365-9161 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran 14588-89694 (Iran, Islamic Republic of); Taghavinia, Nima [Department of Physics, Sharif University of Technology, Tehran 11365-9161 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran 14588-89694 (Iran, Islamic Republic of)

    2015-12-15

    Highlights: • N-doped TiO{sub 2} scattering particles were synthesized for embedding into commercial photoanode of dye sensitized solar cells. • Embedded scatterers improved optical and electrical features of the cells. • These multifunctional scatterers increased cell performance up to 17%. - Abstract: Aggregated sub-micron size nitrogen doped TiO{sub 2} (N-TiO{sub 2}) particles with superior optical and electrical features were successfully synthesized for embedding into commercial mesoporous TiO{sub 2} photoelectrode of dye sensitized solar cells (DSSCs) as the light scattering particles compared to undoped one. X-ray photoelectron spectroscopy and absorption spectra confirmed that the titanium dioxide is sufficiently doped by nitrogen in N-TiO{sub 2} sample. Employing these high-surface N-TiO{sub 2} in mesoporous photoelectrode of solar cells, the power conversion efficiency of 8% has been achieved which shows 17% improvement for the optimum embedded level of doping (30 wt%) compared to commercial photoelectrode without additive; while enhanced efficiency is only 3% embedding undoped sub-micron size TiO{sub 2} particles. These results can introduce the novel multifunctional photoelectrode for nanostructured solar cells with enhanced values of scattering efficiency and improved electrical features including trap states density reduction in comparison to commercial mesoporous photoelectrodes.

  14. Plasmonic excitations on metallic nanowires embedded in silica photonic crystal fibers

    Energy Technology Data Exchange (ETDEWEB)

    Prill Sempere, Luis

    2010-06-17

    This thesis describes the theoretical and experimental investigation of metal-filled photonic crystal fibers (PCFs) and their fabrication. The thesis explains how to overcome the obstacles when infiltrating molten metals into sub-micron holes in fused silica (SiO{sub 2}) PCF. The optical properties of such filled fibers are theoretically and experimentally investigated, focusing on the coupling between the core mode of the fibers and the surface plasmon polaritons (SPPs) on the metal wires. The thesis introduces the ideas, physical challenges and results of two new filling techniques: the pressure cell technique and the splicing technique. These techniques make it possible for the first time to fill different fiber structures with sub-micron sized holes, such as PCFs and single-hole capillaries, with different metals like gold (Au) and silver (Ag). Samples with hole diameters between 120 nm and 20 {mu}m and aspect ratios as high as 75000 have been realized. Theoretical simulations and models have been developed in order to understand the optical behavior of these novel structures. The light guided in the core of the filled PCF structure will couple to SPP modes on the wires. Several measurements have been performed to determine the resonance wavelengths and losses of such filled PCF structures. Also, different phenomena such as the shift of the resonance position with the wire diameter or pitch and the polarization dependence of SPP in polarization maintaining (PM)-PCF have been investigated. The fabrication of free standing metal arrays was another focus of this work. The critical question was how to remove the surrounding SiO{sub 2} from the metal wires. Two different approaches have been tried: etching of the SiO{sub 2} and cleaving the PCF. (orig.)

  15. Ablation of metals using ultrashort laser pulses in a pump-probe experiment dynamics of laser induced particle emission from metal surfaces on the femto and picosecond time scale

    CERN Document Server

    Schmidt, V

    2001-01-01

    The main part of this work deals with the dynamics of the laser ablation process of metals (Al, Ag, Fe and Ni) initiated by approx. 50 fs laser pulses. The phenomena have been investigated by interferometric time resolved pump and probe measurements. This work reports one of the first yield measurements of emitted singly charged ions and neutrals from a metal surface induced by laser light. The experiments have been performed using a two-pulse autocorrelation setup in which the differential yield of emitted metal ions is measured as a function of the temporal separation between a pair of excitation pulses with a reflectron-type time-of-flight (TOF) spectrometer. The intensity of each pulse is kept below the ablation threshold, thus only the combined interaction of both pulses causes particle emission. It must be pointed out, that the time information obtained in this way concerns only the initial excitation responsible for ablation, but does not yield information about the dynamics of the way this excitation ...

  16. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marcak, Adrian; Corbella, Carles, E-mail: carles.corbella@rub.de; Keudell, Achim von [Research Group Reactive Plasmas, Ruhr-University Bochum, 44801 Bochum (Germany); Arcos, Teresa de los [Technical and Macromolecular Chemistry, Paderborn University, 33098 Paderborn (Germany)

    2015-10-15

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  17. Improvement in the Design of Metal-Ceramic High Voltage Feedthroughs for use in High Energy Particle Accelerators

    CERN Document Server

    Weterings, W

    1999-01-01

    Large high-voltage devices operate in particle accelerators to steer charged particles in the desired direction. Solid and hollow rods of sintered alumina are used as insulating supports and high-voltage feedthroughs to power the electrodes of these electrostatic systems. The performance of the systems is often limited by voltage breakdown along the surface of the ceramic insulator (so-called surface flashover) or discharge between feedthrough and vacuum tank, which can lead to significant disruptions in terms of overall machine efficiency. Available results on the influence of the mechanical preparation, thermal history and particular cleaning techniques on commercially obtainable alumina samples have been studied in order to investigate possibilities for better preparation methodology of the insulating supports. Also the influence of the relative position of the feedthrough inside the vacuum tank on the high-voltage breakdown behaviour has been studied. This paper describes the theoretical and practical bac...

  18. Novel Method for Floating Synthesizing Heavy Metal Particles as Flowing Anode of Zinc-Air Fuel Cell

    Directory of Open Access Journals (Sweden)

    Chen Yang Wu

    2014-01-01

    Full Text Available In this study, centrally hollow microspheres of zinc were synthesized. The microspheres were then mixed with KOH electrolyte to form zinc sol, which was coagulated and precipitated. Afterward, we employed a novel technique to enable the permanent floating of zinc particles, which involved stirring zinc sol with air using a magnetic stirrer. This resulted in the formation of foam in which the zinc particles permanently floated. We then added 65 wt% of the electrolyte (KOH to prepare 35 wt% of zinc sol. We tested the cell and found the values of current density, specific energy, and electric capacity to be 7.41 mA/cm2, 840.14 Wh/kg, and 3023 mAh, respectively.

  19. A study of CuZr-based bulk metallic glass composite dispersed by in-situ Ta particles

    Science.gov (United States)

    Wang, Dongmei; Mu, Juan; Xie, Qingge; Xu, Haijian; Wang, Yandong; Zhang, Haifeng

    2017-05-01

    The microstructure and mechanical behavior of Cu46Zr41Al7Nb1Ta5 BMGC containing Ta-rich particles and B2 phase were investigated. The parabolic strain-hardening behavior is observed due to the martensitic transformation of the B2 phase. The stress behavior of B2 phase dominates the macro-mechanical behavior rather than the shear-banding deformation.

  20. Fabrication of magnetite nano particles and modification with metal organic framework of Zn(2+) for sorption of doxycyline.

    Science.gov (United States)

    Ghassemi Nooreini, Mahsa; Ahmad Panahi, Homayon

    2016-10-15

    This study presents a novel method for synthesis and characterization of a metal-organic framework and application in drug delivery. The first step was synthesis of amino functionalized magnetite that was then modified by a metal-organic framework of Zn(2+). This newly developed nano-sorbent was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometer and x-ray diffraction. Doxycycline was loaded to the nano-sorbent and effects of the variable parameters, kinetics of adsorption, release and capacity of adsorption were investigated. Test results specified maximum sorption of 21.5mgg(-1) for doxycycline in conditions of nano-sorbent at pH 7 and optimum time of 10min. Equilibrium adsorption data were analyzed by the Langmuir, Freundlich and Temkin models. Results showed that about 40% of doxycycline was released in simulated gastric fluid for the 30min and more than 70% was released in simulated intestinal fluid during 12h. These results were satisfactory and demonstrate that this new nano-sorbent modified with metal-organic framework had a good level of efficiency for drug delivery of doxycycline. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Electrical properties of epoxy resin based nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Tuncer, Enis [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Sauers, Isidor [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); James, D Randy [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Ellis, Alvin R [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Paranthaman, M Parans [Materials Chemistry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Aytug, Tolga [Materials Chemistry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Sathyamurthy, Srivatsan [Materials Chemistry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); More, Karren L [Microscopy Microanalysis and Microstructures Group, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Li, Jing [Superconductive and Energy Efficient Materials Group, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Goyal, Amit [Superconductive and Energy Efficient Materials Group, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2007-01-17

    We investigate the electrical properties of composite materials prepared as nano- and sub-micron-scale metal-oxide particles embedded in a commercial resin. The filler particles are barium titanate and calcium copper titanate. The physical and structural characteristics of the constituents and the fabricated composites are reported. Electrical characterization of the composite samples is performed using time- and frequency-domain dielectric spectroscopy techniques. The electrical breakdown strength of samples with nano- and sub-micron-sized particles have better electrical insulation properties than the unfilled resin.

  2. Effect of antiscalants on precipitation of an RO concentrate: metals precipitated and particle characteristics for several water compositions.

    Science.gov (United States)

    Greenlee, Lauren F; Testa, Fabrice; Lawler, Desmond F; Freeman, Benny D; Moulin, Philippe

    2010-04-01

    Inland brackish water reverse osmosis (RO) is economically and technically limited by the large volume of salty waste (concentrate) produced. The use of a controlled precipitation step, followed by solid/liquid separation (filtration), has emerged as a promising side-stream treatment process to treat reverse osmosis concentrate and increase overall system recovery. The addition of antiscalants to the RO feed prevents precipitation within the membrane system but might have a deleterious effect on a concentrate treatment process that uses precipitation to remove problematic precipitates. The effects of antiscalant type and concentration on salt precipitation and precipitate particle morphology were evaluated for several water compositions. The primary precipitate for the synthetic brackish waters tested was calcium carbonate; the presence of magnesium, sulfate, minor ions, and antiscalant compounds affected the amount of calcium precipitated, as well as the phases of calcium carbonate formed during precipitation. Addition of antiscalant decreased calcium precipitation but increased incorporation of magnesium and sulfate into precipitating calcium carbonate. Antiscalants prevented the growth of nucleated precipitates, resulting in the formation of small (100-200 nm diameter) particles, as well as larger (6-10 microm) particles. Elemental analysis revealed changes in composition and calcium carbonate polymorph with antiscalant addition and antiscalant type. Results indicate that the presence of antiscalants does reduce the extent of calcium precipitation and can worsen subsequent filtration performance. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  3. Evaluation of the molecular mechanisms associated with cytotoxicity and inflammation after pulmonary exposure to different metal-rich welding particles.

    Science.gov (United States)

    Shoeb, Mohammad; Kodali, Vamsi; Farris, Breanne; Bishop, Lindsey M; Meighan, Terence; Salmen, Rebecca; Eye, Tracy; Roberts, Jenny R; Zeidler-Erdely, Patti; Erdely, Aaron; Antonini, James M

    2017-08-01

    Welding generates a complex aerosol of incidental nanoparticles and cytotoxic metals, such as chromium (Cr), manganese (Mn), nickel (Ni), and iron (Fe). The goal was to use both in vivo and in vitro methodologies to determine the mechanisms by which different welding fumes may damage the lungs. Sprague-Dawley rats were treated by intratracheal instillation (ITI) with 2.0 mg of gas metal arc-mild steel (GMA-MS) or manual metal arc-stainless steel (MMA-SS) fumes or saline (vehicle control). At 1, 3, and 10 days, bronchoalveolar lavage (BAL) was performed to measure lung toxicity. To assess molecular mechanisms of cytotoxicity, RAW264.7 cells were exposed to both welding fumes for 24 h (0-100 μg/ml). Fume composition was different: MMA-SS (41% Fe, 29% Cr, 17% Mn, 3% Ni) versus GMA-MS (85% Fe, 14% Mn). BAL indicators of lung injury and inflammation were increased by MMA-SS at all time points and by GMA-MS at 3 and 10 days after exposure. RAW264.7 cells exposed to MMA-SS had elevated generation of reactive oxygen species (ROS), protein-HNE (P-HNE) adduct formation, activation of ERK1/2, and expression of cyclooxygenase-2 (COX-2) compared to GMA-MS and control. Increased generation of ROS due to MMA-SS exposure was confirmed by increased expression of Nrf2 and heme oxygenase-1 (HO-1). Results of in vitro studies provide evidence that stainless steel welding fume mediate inflammatory responses via activation of ROS/P-HNE/ERK1/2/Nrf2 signaling pathways. These findings were corroborated by elevated expression of COX-2, Nrf2, and HO-1 in homogenized lung tissue collected 1 day after in vivo exposure.

  4. The influence of particle size distribution on the properties of metal-injection-moulded 17-4 PH stainless steel

    CSIR Research Space (South Africa)

    Seerane, Mandy

    2016-10-01

    Full Text Available .V. and GERMAN, R.M. 2009. Effect of powders and binders on material properties and molding parameters in iron and stainless steel powder injection molding process. Powder Technology, vol. 193, no. 2. pp. 162–169. AMIN, S.Y.M., JAMALUDIN, K.R. and MUHAMAD, N.... Metallurgical and Materials Transactions A, vol. 23A, May. pp. 1455–1465. GERMAN, R.M. 2005. Powder Metallurgy and Particulate Materials Processing. Metal Powder Industries Federation, Princeton, NJ, USA. GERMAN, R.M. and BOSE, A. 1997. Injection Molding...

  5. A marine biogenic source of atmospheric ice-nucleating particles

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, T. W.; Ladino, L. A.; Alpert, Peter A.; Breckels, M. N.; Brooks, I. M.; Browse, J.; Burrows, Susannah M.; Carslaw, K. S.; Huffman, J. A.; Judd, C.; Kilthau, W. P.; Mason, R. H.; McFiggans, Gordon; Miller, L. A.; Najera, J.; Polishchuk, E. A.; Rae, S.; Schiller, C. L.; Si, M.; Vergara Temprado, J.; Whale, Thomas; Wong, J P S; Wurl, O.; Yakobi-Hancock, J. D.; Abbatt, JPD; Aller, Josephine Y.; Bertram, Allan K.; Knopf, Daniel A.; Murray, Benjamin J.

    2015-09-09

    The formation of ice in clouds is facilitated by the presence of airborne ice nucleating particles1,2. Sea spray is one of the major global sources of atmospheric particles, but it is unclear to what extent these particles are capable of nucleating ice3–11. Here we show that material in the sea surface microlayer, which is enriched in surface active organic material representative of that found in sub-micron sea- spray aerosol12–21, nucleates ice under conditions that occur in mixed-phase clouds and high-altitude ice clouds. The ice active material is likely biogenic and is less than ~0.2 ?m in size. We also show that organic material (exudate) released by a common marine diatom nucleates ice when separated from cells and propose that organic material associated with phytoplankton cell exudates are a candidate for the observed ice nucleating ability of the microlayer samples. By combining our measurements with global model simulations of marine organic aerosol, we show that ice nucleating particles of marine origin are dominant in remote marine environments, such as the Southern Ocean, the North Pacific and the North Atlantic.

  6. Effects of particle size and forming pressure on pore properties of Fe-Cr-Al porous metal by pressureless sintering

    Science.gov (United States)

    Koo, Bon-Uk; Yi, Yujeong; Lee, Minjeong; Kim, Byoung-Kee

    2017-03-01

    With increased hydrogen consumption in ammonia production, refining and synthesis, fuel cells and vehicle industries, development of the material components related to hydrogen production is becoming an important factor in industry growth. Porous metals for fabrication of hydrogen are commonly known for their relative excellence in terms of large area, lightness, lower heat capacity, high toughness, and permeability. Fe-Cr-Al alloys not only have high corrosion resistance, heat resistance, and chemical stability but also ductility, excellent mechanical properties. In order to control powder size and sintering temperature effects of Fe-Cr-Al porous metal fabrication, Fe-Cr-Al powder was classified into 25-35 μm, 35-45 μm, 45-75 μm using an auto shaking sieve machine and then classified Fe-Cr-Al powders were pressed into disk shapes using a uniaxial press machine and CIP. The pelletized Fe-Cr-Al specimens were sintered at various temperatures in high vacuum. Properties such as pore size, porosity, and air permeability were evaluated using perm-porosimetry. Microstructure and phase changes were observed with SEM and XRD. Porosity and relative density were proportionated to increasing sintering temperature. With sufficient sintering at increasing temperatures, the pore size is expected to be gradually reduced. Porosity decreased with increasing sintering temperature and gradually increased necking of the powder.

  7. Distribution of metals in various particle-size fractions in topsoils of a small dry valley system (European Russia, forest zone)

    Science.gov (United States)

    Samonova, Olga; Aseyeva, Elena

    2017-04-01

    A detailed study of heavy metals distribution in various soil grain-size fractions helps to increase the knowledge about the complex nature of metals' occurrence and their distribution pathways in the environment. On the basis of particle size fractionation of topsoil horizons we examined the specific behavior of heavy metals in a small erosional landform located in the humid temperate zone of the Russian Plain. The object of the study is a 400 m small U-shaped dry valley (balka in Russian) with a catchment area of 32.8 ha located in the central part of the Protva river basin, 100 km southwest of Moscow. The uppermost parts of the landform are incised in Late Pleistocene loessial loams, which cover significant portions of interfluve area in the region, while the middle and the lower parts cut through Middle Pleistocene glacial sediments. A total of 50 samples were collected from topsoil horizons of different landform geomorphic units along three cross-sections as well as along the bottom of the landform and its detrital fan. Samples were analyzed for Mn, Cu, Ni, Co, Cr, Zn, Pb, Ti, Zr, and Fe content. Eleven samples were chosen for physical fractionation into 5 grain-size fractions (1-0.25 mm, 0.25-0.05 mm, 0.05-0.01 mm, 0.01-0.001 mm and calculated for Cu, Ni, Co, Fe, Mn, Ti and Zr reach their maximum in the 1-0.25 mm fraction (for Cu and Ni exceeding 75%, for Ti, Zr being around 40%). For Zn, Cr and Pb the maximum variation (50-60%) was found in the 0.25-0.05 mm fraction. In contrast, the two studied silt fractions and also the clay showed very low variations of all metal contents (except for Mn) characteristically in the range between 6% (Cr) and 23.5% (Zn). Unlike the finer fractions, which displayed very poor geochemical differentiation across the landform's geomorphic units, the coarser (sand) fractions showed distinct spatial patterns in the elements' distribution, possibly related to migration processes, the depletion of metals in the landforms' slopes and

  8. Analysis of trace rare earth elements in misch metal by means of ITP-PIXE (isotachophoresis - Particle Induced X-ray Emission) method

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian-Ying; Hirokawa, Takeshi; Nishiyama, Fumitaka; Kimura, Goji; Kiso, Yoshiyuki; Ito, Kazuaki; Shoto, Eiji [Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Engineering

    1993-12-31

    A misch metal, an alloy of light rare earth elements, was analyzed by a new coupled analytical method, ITP-PIXE (isotachophoresis - Particle Induced X-ray Emission): The sample solution containing ca.1 mg misch metal was separated and fractionated by the use of a preparative isotachophoretic analyzer. The dropwise fractions containing nanomole rare earth elements were analyzed off-line by PIXE. The matrix effect in X-ray measurement was reduced by the isotachophoretic removing of the dominant lanthanoids and preconcentration of the trace elements of interest. Consequently the minor elements, Sm, Gd, Tb, Dy, Ho, Er, Yb and Y could be determined accurately. The most trace element found was Yb (4ppm, 4ng in 1mg sample). The good accuracy of ITP-PIXE method was also demonstrated for several model samples of lanthanoids, where La was the dominant element and the thirteen lanthanoids were the minor elements. The ratio was varied from 500:1 to 50000:1. Even in the case of 50000:1, ca.10% accuracy was achieved for each minor element except for Sm(23%), Gd(17%) and Yb(18%). The analytical results by ITP-PIXE were compared with those by means of ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometry). (author).

  9. Internal damping due to dislocation movements induced by thermal expansion mismatch between matrix and particles in metal matrix composites. [Al/SiC

    Energy Technology Data Exchange (ETDEWEB)

    Girand, C.; Lormand, G.; Fougeres, R.; Vincent, A. (GEMPPM, Villeurbanne (France))

    1993-05-01

    In metal matrix composites (MMCs), the mechanical 1 of the reinforcement-matrix interface is an important parameter because it governs the load transfer from matrix to particles, from which the mechanical properties of these materials are derived. Therefore, it would be useful to set out an experimental method able to characterize the interface and the adjacent matrix behaviors. Thus, a study has been undertaken by means of internal damping (I.D.) measurements, which are well known to be very sensitive for studying irreversible displacements at the atomic scale. More especially, this investigation is based on the fact that, during cooling of MMC's, stress concentrations originating from differences in coefficients of thermal expansion (C.T.E.) of matrix and particles should induce dislocation movements in the matrix surrounding the reinforcement; that is, local microplastic strains occur. Therefore, during I.D. measurements vs temperature these movements should contribute to MMCs I.D. in a process similar to those involved around first order phase transitions in solids. The aim of this paper is to present, in the case of Al/SiC particulate composites, new developments of this approach that has previously led to promising results in the case of Al-Si alloys.

  10. Nanoscale zero-valent iron particles supported on reduced graphene oxides by using a plasma technique and their application for removal of heavy-metal ions.

    Science.gov (United States)

    Li, Jie; Chen, Changlun; Zhang, Rui; Wang, Xiangke

    2015-06-01

    Nanoscale zero-valent iron particles supported on reduced graphene oxides (NZVI/rGOs) from spent graphene oxide (GO)-bound iron ions were developed by using a hydrogen/argon plasma reduction method to improve the reactivity and stability of NZVI. The NZVI/rGOs exhibited excellent water treatment performance with excellent removal capacities of 187.16 and 396.37 mg g(-1) for chromium and lead, respectively. Moreover, the NZVI/rGOs could be regenerated by plasma treatment and maintained high removal ability after four cycles. X-ray photoelectron spectroscopy analysis results implied that the removal mechanisms could be attributed to adsorption/precipitation, reduction, or both. Such multiple removal mechanisms by the NZVI/rGOs were attributed to the reduction ability of the NZVI particles and the role of dispersing and stabilizing abilities of the rGOs. The results indicated that the NZVI/rGOs prepared by a hydrogen/argon plasma reduction method might be an effective composite for heavy-metal-ion removal. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. High-Temperature Active Soldering of SiC Particle-Reinforced Al-MMC Using a Novel ZnAlGaMgTi Filler Metal

    Science.gov (United States)

    Chen, Biqiang; Zhang, Guifeng; Zhang, Linjie; Xu, Tingting

    2017-10-01

    In order to broaden the application of SiC particle-reinforced aluminum matrix composite in electronics packaging, newly developed ZnAlGaMgTi filler with a low melting point of 418-441 °C was utilized as filler metal for active soldering of aluminum matrix composites (70 vol.%, SiCp/Al-MMCs) for the first time. The effect of loading pressure on joint properties of ZnAlGaMgTi active filler was investigated. The experimental results indicated that novel filler could successfully solder Al-MMCs, and the presence of Mg in the filler enhanced the penetration of Zn, while the forming of Zn-rich barrier layer influenced the active element MPD (melting point depressant) diffusion into parent composite, and the bulk-like (Mg-Si)-rich phase and Ti-containing phase were readily observed at the interface and bond seam. With the increase in loading pressure, the runout phenomenon appeared more significant, and the filler foil thickness and the Zn penetration depth varied pronouncedly. Sound joints with maximum shear strength of 29.6 MPa were produced at 480 °C at 1 MPa, and the crack occurred adjacent to the boundary of SiC particle and then propagated along the interface. A novel model describing the significant mutual diffusion of Al and Zn atoms between the parent material and solder was proposed.

  12. Particle formation and plasma radiative losses during laser ablation suitability of the Sedov-Taylor scaling.

    Science.gov (United States)

    Palanco, Santiago; Marino, Salvatore; Gabás, Mercedes; Bijani, Shanti; Ayala, Luis; Ramos-Barrado, José R

    2014-06-30

    Deviations of the Sedov-Taylor scaling at three different laser ablation regimes (500 mJ in a 0.8 mm spot, 50 mJ in a 0.8 mm spot and 500 mJ in a 2.5 mm spot) were investigated using Schlieren photography in combination with optical scattering and optical emission spectrometry, among others. For each case, the time evolution of the shock front was related to the formation, expansion and properties of the plasma. Both, the time scale of the different radiative processes and that observed for vapor condensation into nanoparticles and sub-micron particles are compatible with the divergences found between the model and experimental data.

  13. EVALUATION OF ACOUSTIC FORCES ON A PARTICLE IN AEROSOL MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Richard Dimenna, R

    2007-09-27

    The acoustic force exerted on a solid particle was evaluated to develop a fundamental understanding of the critical physical parameters or constraints affecting particle motion and capture in a collecting device. The application of an acoustic force to the collection of a range of submicron-to-micron particles in a highly turbulent airflow stream laden with solid particles was evaluated in the presence of other assisting and competing forces. This scoping estimate was based on the primary acoustic force acting directly on particles in a dilute aerosol system, neglecting secondary interparticle effects such as agglomeration of the sub-micron particles. A simplified analysis assuming a stable acoustic equilibrium with an infinite sound speed in the solid shows that for a solid-laden air flow in the presence of a standing wave, particles will move toward the nearest node. The results also show that the turbulent drag force on a 1-{micro}m particle resulting from eddy motion is dominant when compared with the electrostatic force or the ultrasonic acoustic force. At least 180 dB acoustic pressure level at 1 MHz is required for the acoustic force to be comparable to the electrostatic or turbulent drag forces in a high-speed air stream. It is noted that particle size and pressure amplitude are dominant parameters for the acoustic force. When acoustic pressure level becomes very large, the acoustic energy will heat up the surrounding air medium, which may cause air to expand. With an acoustic power of about 600 watts applied to a 2000-lpm air flow, the air temperature can increase by as much as 15 C at the exit of the collector.

  14. Characteristics of trace metals in fine (PM2.5) and inhalable (PM10) particles and its health risk assessment along with in-silico approach in indoor environment of India

    National Research Council Canada - National Science Library

    Satsangi, P. Gursumeeran; Yadav, Suman; Pipal, Atar Singh; Kumbhar, Navanath

    2014-01-01

    ...: aerodynamic diameter [less than or equal to] 10 [mu]m) particles and its associated toxic metals are of concern now-a-days due to its effects on human health and environment. PM.sub.10 and PM.sub...

  15. Power handling of a liquid-metal based CPS structure under high steady-state heat and particle fluxes

    Directory of Open Access Journals (Sweden)

    T.W. Morgan

    2017-08-01

    Full Text Available Liquid metal infused capillary porous structures (CPSs are considered as a potential divertor solution for DEMO due to their potential power handling capability and resilience to long term damage. In this work the power handling and performance of such Sn-based CPS systems is assessed both experimentally and via modelling. A Sn-CPS target was exposed to heat fluxes of up to 18.1 MW m−2 in He plasma in the Pilot-PSI linear device. Post-mortem the target showed no damage to nor any surface exposure of the underlying W-CPS felt. The small pore size (∼40µm employed resulted in no droplet formation from the target in agreement with calculated Rayleigh-Taylor and Kelvin-Helmoholtz instability thresholds. The temperature response of the Sn-target was used to determine the thermal conductivity of the mixed Sn-CPS material using COMSOL modelling. These values were then used via further finite element analysis to extrapolate to DEMO relevant monoblock designs and estimate the maximum power handling achievable based on estimated temperature windows for all component elements of the design. For an optimized design a heat-load of up to 20 MW m−2 may be received while the use of CPS also offers other potential design advantages such as the removal of interlayer requirements.

  16. Rapid degradation of phenol by ultrasound-dispersed nano-metallic particles (NMPs) in the presence of hydrogen peroxide: A possible mechanism for phenol degradation in water.

    Science.gov (United States)

    Singh, Jiwan; Yang, Jae-Kyu; Chang, Yoon-Young

    2016-06-15

    The present study was carried out to investigate the degradation of phenol by ultrasonically dispersed nano-metallic particles (NMPs) in an aqueous solution of phenol. Leaching liquor from automobile shredder residue (ASR) was used to obtain the NMPs. The prepared NMPs were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and by X-ray diffraction (XRD). The SEM images show that the diameters of the NMPs were less than 50 nm. An SEM-EDX elemental analysis reveals that Fe was the most commonly found element (weight %) in the NMPs. The FTIR and XRD peaks indicate the presence of metals oxides on the surfaces of the NMPs. The results of the XPS analysis indicate that various elements (e.g., C, O, Zn, Cu, Mn, Fe) are present on the surfaces of the NMPs. The effects of the NMP dose, the initial solution pH, and of different concentrations of phenol and H2O2 on the phenol degradation characteristics were evaluated. The results of this study demonstrate that phenol degradation can be improved by increasing the amount of NMPs, whereas it is reduced with an increase in the phenol concentration. The degradation of phenol by ultrasonically dispersed NMPs followed the pseudo-first-order kinetics. The probable mechanism of phenol degradation by ultrasonically dispersed NMPs was the oxidation of phenol caused by the hydroxyl radicals produced during the reaction between H2O2 and the NMPs during the ultrasonication process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Distribution of heavy metals and metalloids in bulk and particle size fractions of soils from coal-mine brownfield and implications on human health.

    Science.gov (United States)

    Li, Hongxia; Ji, Hongbing; Shi, Chunjing; Gao, Yang; Zhang, Yan; Xu, Xiangyu; Ding, Huaijian; Tang, Lei; Xing, Yuxin

    2017-04-01

    Heavy metals (HMs) and metalloids migrate into their surroundings, thus increasing environmental risks and threatening human health. Current studies on coal-mine brownfields, however, have not thoroughly investigated soil-associated HMs and metalloids produced by coal mining. Therefore, this study explored the spatial and particle fraction distribution and human health implications of HMs and metalloids. The soil-associated HMs and metalloids are Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Nickel (Ni), Lead (Pb), Scandium (Sc), Titanium (Ti) and Zinc (Zn). Results showed that Cd, Cu, Pb, and Ni were enriched in bulk soils. Cadmium, Cu and Pb from anthropogenic source were mainly found at entrance roadsides and in sites closest to coal mines. HMs and metalloids primarily accumulated in fine fractions (<1, 1-5, and 5-10 μm). Moreover, HM and metalloid loadings substantially accumulated in the 75-250 μm and 250-1000 μm fractions. Most fine soil fractions showed moderate to strong potential ecological risks, whereas all the coarse particle fractions (50-75, 75-250, and 250-1000 μm) presented slight potential ecological risk. Exposure to soil-associated HMs and metalloids mainly occurred via ingestion. The total non-carcinogenic risks to children and adults fell below the safe level of 1, whereas the total carcinogenic risks to these individuals were higher than that of the maximum acceptable level set by the United States Environmental Protection Agency (USEPA, 1 × 10 -4). The total carcinogenic risk was mainly contributed by Cd and Ni through ingestion and dermal access. Therefore, hygiene and food security in areas should be emphasized. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Solid Particle Formation Mechanisms.

    Science.gov (United States)

    1986-04-01

    3421. Kuka , K., N. Wads, and A. Tasaki, "Magnetic Properties of Ferromagnetic Metal Alloy Flue Particles Prepared by Evaporation In Inert Gases," Japanese J. Applied Physics, Vol. 8, 1969, p. 603. [ II 7-- IATI.

  19. Coke industry and steel metallurgy as the source of soil contamination by technogenic magnetic particles, heavy metals and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Rachwał, Marzena; Magiera, Tadeusz; Wawer, Małgorzata

    2015-11-01

    Application of integrated magnetic, geochemical and mineralogical methods for qualitative and quantitative assessment of forest topsoils exposed to the industrial emissions was the objective of this manuscript. Volume magnetic susceptibility (κ) in three areas of southern Poland close to the coke and metallurgical plants was measured directly in the field. Representative topsoil samples were collected for further chemical and mineralogical analyses. Topsoil magnetic susceptibility in the studied areas depended mainly on the content of technogenic magnetic particles (TMPs) and decreased downwind at increasing distance from the emitters. In the vicinity of coking plants a high amount of polycyclic aromatic hydrocarbons (PAHs) was observed, especially the most carcinogenic ones with four- and five-member rings. No significant concentration of TMPs (estimated on the base of κ values) and heavy metals (HM) was observed in area where the coke plant was the only pollution source. In areas with both coke and metallurgical industry, higher amounts of TMPs, PAHs and HM were detected. Morphological and mineralogical analyses of TMPs separated from contaminated soil samples revealed their high heterogeneity in respect of morphology, grain size, mineral and chemical constitution. Pollution load index and toxicity equivalent concentration of PAHs used for soil quality assessment indicated its high level of pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. An optical investigation of nano-crystalline CaF2 particles doped with Nd3+ ions

    Science.gov (United States)

    O'Dwyer, C.; James, H. J.; Cheu, B.; Jaque, F.; Han, T. P. J.

    2017-10-01

    Good crystalline quality CaF2 sub-micron size particles doped with neodymium ions have been produced by the co-precipitation process and their crystallinity have been further improved by thermal treatment at 500 °C. Core and surface related luminescence defect centres have been identified and the effects of Y3+ and Yb3+ codopants are also investigated. Core defects centres are associated with single-ion and multi-ion defect centres as observed in bulk single crystal whereas the origin of the surface or near surface defect, A‧, centre has been ascertained to be derived from a single-ion centre most probably charge compensated by a hydroxyl group.

  1. Particles, contacts, bulk behavior

    NARCIS (Netherlands)

    Luding, Stefan; Tomas, J.

    2014-01-01

    Granular matter consists of discrete “particles”. These can be separate sand-grains, agglomerates (made of many primary particles), or solid materials like rock, composites, or metal-alloys—all with particulate inhomogeneous, possibly anisotropic micro-structure. Particles can be as small as

  2. Estudo das partículas totais em suspensão e metais associados em áreas urbanas Study of total suspended particles and the associated metals in urban areas

    Directory of Open Access Journals (Sweden)

    Fabiana Goulart de Carvalho

    2000-10-01

    Full Text Available This work aims at the study of the air quality determination regarding the total suspended particles (TSP and the associated metals in the counties of Charqueadas and Sapucaia do Sul at the state of Rio Grande do Sul. The TSP samples were collected using high volume samplers and the analysis of the metallic elements was accomplished through ICP-AES. The results revealed that the TSP concentrations, found in the two studied regions, have exceded the current air quality patterns established by the Brazilian Legislation. They also revealed high levels of several of the elements being attributed to the presence of anthropogenic sources. The correlation between meteorological data (speed and wind direction and TSP concentrations were significant and revealed strong influence in particle dispersion.

  3. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  4. Mapping strain fields induced in Zr-based bulk metallic glasses during in-situ nanoindentation by X-ray nanodiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gamcová, J.; Bednarčík, J.; Franz, H. [DESY, Notkestraße 85, Hamburg 22547 (Germany); Mohanty, G.; Wehrs, J.; Michler, J. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstraße 39, Thun 3602 (Switzerland); Michalik, Š. [Institute of Physics ASCR, Na Slovance 2, Praha 18221 (Czech Republic); Krywka, C. [HZG, Institut für Werkstoffforschung, Notkestraße 85, Hamburg 22547 (Germany); Breguet, J. M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstraße 39, Thun 3602 (Switzerland); Alemnis GmbH, Feuerwerkerstraße 39, Thun 3602 (Switzerland)

    2016-01-18

    A pioneer in-situ synchrotron X-ray nanodiffraction approach for characterization and visualization of strain fields induced by nanoindentation in amorphous materials is introduced. In-situ nanoindentation experiments were performed in transmission mode using a monochromatic and highly focused sub-micron X-ray beam on 40 μm thick Zr-based bulk metallic glass under two loading conditions. Spatially resolved X-ray diffraction scans in the deformed volume of Zr-based bulk metallic glass covering an area of 40 × 40 μm{sup 2} beneath the pyramidal indenter revealed two-dimensional map of elastic strains. The largest value of compressive elastic strain calculated from diffraction data at 1 N load was −0.65%. The region of high elastic compressive strains (<−0.3%) is located beneath the indenter tip and has radius of 7 μm.

  5. Two dimensional, electronic particle tracking in liquids with a graphene-based magnetic sensor array

    Science.gov (United States)

    Neumann, Rodrigo F.; Engel, Michael; Steiner, Mathias

    2016-07-01

    The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual nanoparticles in the liquid with high accuracy and (b) the reconstruction of a particle's flow-driven trajectory across the integrated sensor array with sub-pixel precision as a function of time, in what we call the ``Magnetic nanoparticle velocimetry'' technique. Since the method does not rely on optical detection, potential lab-on-chip applications include particle tracking and flow analysis in opaque media at the sub-micron scale.The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual

  6. A comparative study of submicron particle sizing platforms: accuracy, precision and resolution analysis of polydisperse particle size distributions.

    Science.gov (United States)

    Anderson, Will; Kozak, Darby; Coleman, Victoria A; Jämting, Åsa K; Trau, Matt

    2013-09-01

    The particle size distribution (PSD) of a polydisperse or multimodal system can often be difficult to obtain due to the inherent limitations in established measurement techniques. For this reason, the resolution, accuracy and precision of three new and one established, commercially available and fundamentally different particle size analysis platforms were compared by measuring both individual and a mixed sample of monodisperse, sub-micron (220, 330, and 410 nm - nominal modal size) polystyrene particles. The platforms compared were the qNano Tunable Resistive Pulse Sensor, Nanosight LM10 Particle Tracking Analysis System, the CPS Instruments's UHR24000 Disc Centrifuge, and the routinely used Malvern Zetasizer Nano ZS Dynamic Light Scattering system. All measurements were subjected to a peak detection algorithm so that the detected particle populations could be compared to 'reference' Transmission Electron Microscope measurements of the individual particle samples. Only the Tunable Resistive Pulse Sensor and Disc Centrifuge platforms provided the resolution required to resolve all three particle populations present in the mixed 'multimodal' particle sample. In contrast, the light scattering based Particle Tracking Analysis and Dynamic Light Scattering platforms were only able to detect a single population of particles corresponding to either the largest (410 nm) or smallest (220 nm) particles in the multimodal sample, respectively. When the particle sets were measured separately (monomodal) each platform was able to resolve and accurately obtain a mean particle size within 10% of the Transmission Electron Microscope reference values. However, the broadness of the PSD measured in the monomodal samples deviated greatly, with coefficients of variation being ~2-6-fold larger than the TEM measurements across all four platforms. The large variation in the PSDs obtained from these four, fundamentally different platforms, indicates that great care must still be taken in

  7. High sensitivity detection and sorting of infectious human immunodeficiency virus (HIV-1) particles by flow virometry.

    Science.gov (United States)

    Bonar, Michał M; Tilton, John C

    2017-05-01

    Detection of viruses by flow cytometry is complicated by their small size. Here, we characterized the ability of a standard (FACSAria II) and a sub-micron flow cytometer (A50 Micro) to resolve HIV-1 viruses. The A50 was superior at resolving small particles but did not reliably distinguish HIV-1, extracellular vesicles, and laser noise by light scatter properties alone. However, single fluorescent HIV-1 particles could readily be detected by both cytometers. Fluorescent particles were sorted and retained infectivity, permitting further exploration of the functional consequences of HIV-1 heterogeneity. Finally, flow cytometry had a limit of detection of 80 viruses/ml, nearly equal to PCR assays. These studies demonstrate the power of flow cytometry to detect and sort viral particles and provide a critical toolkit to validate methods to label wild-type HIV-1; quantitatively assess integrity and aggregation of viruses and virus-based therapeutics; and efficiently screen drugs inhibiting viral assembly and release. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Rapid search and quantitative analysis of gunshot residue particles in the SEM.

    Science.gov (United States)

    Lebiedzik, J; Johnson, D L

    2000-01-01

    Automated scanning electron microscopy coupled with image analysis and X-ray micro analysis was used to characterize a variety of gunshot residue (GSR) samples. More than 500 rounds of commercially available ammunition and six different types of hand gulls were used in the study of 17 GSR and 19 reference specimens. The individual particle X-ray composition was determined for 12 different elements. Elemental composition of GSR particles was highly variable but consistent with compounds mixed into or associated with a barium oxide matrix. When present in a specimen, GSR could be adequately characterized with automated procedures in less than an hour by restricting analyses to features larger than 2 microm. In "clean" samples, a higher resolution particle search was required to avoid reporting false negatives. Careful control of the back scattered electron signal strength threshold, by reference to a standard, was needed to ensure both time-efficient and accurate analyses. Samples collected from non-shooting subjects. active in a physical environment which contained firearms discharge residue were seen to be easily contaminated by sub-micron GSR particles.

  9. A Generalized Boltzmann Fokker-Planck Method for Coupled Charged Particle Transport

    Energy Technology Data Exchange (ETDEWEB)

    Prinja, Anil K

    2012-01-09

    The goal of this project was to develop and investigate the performance of reduced-physics formulations of high energy charged particle (electrons, protons and heavier ions) transport that are computationally more efficient than not only analog Monte Carlo methods but also the established condensed history Monte Carlo technique. Charged particles interact with matter by Coulomb collisions with target nuclei and electrons, by bremsstrahlung radiation loss and by nuclear reactions such as spallation and fission. Of these, inelastic electronic collisions and elastic nuclear collisions are the dominant cause of energy-loss straggling and angular deflection or range straggling of a primary particle. These collisions are characterized by extremely short mean free paths (sub-microns) and highly peaked, near-singular differential cross sections about forward directions and zero energy loss, with the situation for protons and heavier ions more extreme than for electrons. For this reason, analog or truephysics single-event Monte Carlo simulation, while possible in principle, is computationally prohibitive for routine calculation of charged particle interaction phenomena.

  10. Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

    Directory of Open Access Journals (Sweden)

    Shunsuke Asahina

    2014-11-01

    Full Text Available Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in york-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the york-shell materials: (i resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii sample preparation for observing internal structures; and (iii X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

  11. Red-blood-cell-like BSA/Zn3(PO4)2 hybrid particles: Preparation and application to adsorption of heavy metal ions

    Science.gov (United States)

    Zhang, Baoliang; Li, Peitao; Zhang, Hepeng; Li, Xiangjie; Tian, Lei; Wang, Hai; Chen, Xin; Ali, Nisar; Ali, Zafar; Zhang, Qiuyu

    2016-03-01

    A novel kind of red-blood-cell-like bovine serum albumin (BSA)/Zn3(PO4)2 hybrid particle is prepared at room temperature by a facile and rapid one-step method based on coordination between BSA and zinc ion. The morphology of the monodisperse hybrid particle shows oblate spheroidal type with a one sided single hole on the surface. The hybrid particle is constructed with BSA/Zn3(PO4)2 nanoplates of 35 nm thick. The average particle size of hybrid particle is 2.3 μm, and its BET specific surface area is 146.64 cm2/g. To clarify the evolution of BSA/Zn3(PO4)2 hybrid particle, SEM and elemental analysis as a function of particle growth time are investigated. The formation mechanism of BSA/Zn3(PO4)2 hybrid particle, which can be described as crystallization, coordination and self-assembly process, is illustrated in detail. The as-prepared BSA/Zn3(PO4)2 hybrid particle is used for adsorption of Cu2+. The hybrid particle displayed excellent adsorption properties on Cu2+. The adsorption efficiency of BSA/Zn3(PO4)2 hybrid particles at 5 min and 30 min are 86.33% and 98.9%, respectively. The maximum adsorption capacity is 6.85 mg/g. Thus, this kind of novel adsorbent shows potential application value in ultra-fast and highly efficient removal of Cu2+.

  12. Modeling the role of highly oxidized multifunctional organic molecules for the growth of new particles over the boreal forest region

    Science.gov (United States)

    Öström, Emilie; Putian, Zhou; Schurgers, Guy; Mishurov, Mikhail; Kivekäs, Niku; Lihavainen, Heikki; Ehn, Mikael; Rissanen, Matti P.; Kurtén, Theo; Boy, Michael; Swietlicki, Erik; Roldin, Pontus

    2017-07-01

    In this study, the processes behind observed new particle formation (NPF) events and subsequent organic-dominated particle growth at the Pallas Atmosphere-Ecosystem Supersite in Northern Finland are explored with the one-dimensional column trajectory model ADCHEM. The modeled sub-micron particle mass is up to ˜ 75 % composed of SOA formed from highly oxidized multifunctional organic molecules (HOMs) with low or extremely low volatility. In the model the newly formed particles with an initial diameter of 1.5 nm reach a diameter of 7 nm about 2 h earlier than what is typically observed at the station. This is an indication that the model tends to overestimate the initial particle growth. In contrast, the modeled particle growth to CCN size ranges ( > 50 nm in diameter) seems to be underestimated because the increase in the concentration of particles above 50 nm in diameter typically occurs several hours later compared to the observations. Due to the high fraction of HOMs in the modeled particles, the oxygen-to-carbon (O : C) atomic ratio of the SOA is nearly 1. This unusually high O : C and the discrepancy between the modeled and observed particle growth might be explained by the fact that the model does not consider any particle-phase reactions involving semi-volatile organic compounds with relatively low O : C. In the model simulations where condensation of low-volatility and extremely low-volatility HOMs explain most of the SOA formation, the phase state of the SOA (assumed either liquid or amorphous solid) has an insignificant impact on the evolution of the particle number size distributions. However, the modeled particle growth rates are sensitive to the method used to estimate the vapor pressures of the HOMs. Future studies should evaluate how heterogeneous reactions involving semi-volatility HOMs and other less-oxidized organic compounds can influence the SOA composition- and size-dependent particle growth.

  13. Particle Characterization for a Protein Drug Product Stored in Pre-Filled Syringes Using Micro-Flow Imaging, Archimedes, and Quartz Crystal Microbalance with Dissipation.

    Science.gov (United States)

    Zheng, Songyan; Puri, Aastha; Li, Jinjiang; Jaiswal, Archana; Adams, Monica

    2017-01-01

    Micro-flow imaging (MFI) has been used for formulation development for analyzing sub-visible particles. Archimedes, a novel technique for analyzing sub-micron particles, has been considered as an orthogonal method to currently existing techniques. This study utilized these two techniques to investigate the effectiveness of polysorbate (PS-80) in mitigating the particle formation of a therapeutic protein formulation stored in silicone oil-coated pre-filled syringes. The results indicated that PS-80 prevented the formation of both protein and silicone oil particles. In the case of protein particles, PS-80 might involve in the interactions with the hydrophobic patches of protein, air bubbles, and the stressed surfaces of silicone oil-coated pre-filled syringes. Such interactions played a role in mitigating the formation of protein particles. Subsequently, quartz crystal microbalance with dissipation (QCM-D) was utilized to characterize the interactions associated with silicone oil, protein, and PS-80 in the solutions. Based on QCM-D results, we proposed that PS-80 likely formed a layer on the interior surfaces of syringes. As a result, the adsorbed PS-80 might block the leakage of silicone oil from the surfaces to solution so that the silicone oil particles were mitigated at the presence of PS-80. Overall, this study demonstrated the necessary of utilizing these three techniques cooperatively in order to better understand the interfacial role of PS-80 in mitigating the formation of protein and silicone oil particles.

  14. Scattering Effect of Iron Metallic Particles on the Extinction Coefficient of CaO-SiO2-B2O3-Na2O-Fe2O3-CaF2 Glasses

    Science.gov (United States)

    Yoon, Dae-Woo; Cho, Jung-Wook; Kim, Seon-Hyo

    2016-10-01

    The extinction coefficient of the CaO-SiO2-B2O3-Na2O-Fe2O3-CaF2 glasses has been studied using a FT-IR and a UV-visible spectrometer in the range of 0.5-5 μm to investigate thermal radiation through glassy flux film during continuous casting of steels. In present investigations, iron oxide has been reduced to metallic iron droplets by reaction with graphite crucible during melting, which brings considerable increase of the extinction coefficient due to the scattering. To analyze the scattering effect of these droplets on the extinction coefficient, the number density and size parameter of metallic particles have been measured using an automated scanning electron microscope. The number of metallic particles is intensively proportional to boron contents due to the transition of molar structure, BO4 to BO3, with increasing boron oxide. It is found that calculated scattering coefficients based on Mie scattering theory are in good agreement with measured ones. As the increased scattering coefficient of glassy film would not cause any serious side effects on casting operations, utilization of scattering effects is believed to be significantly essential for the future design of commercial mold fluxes.

  15. Reactions Between Vapor Phase Lead Compounds and In Situ Generated Silica Particles at Various Lead-Silicon Feed Ratios: Applications to Toxic Metal Capture in Combustors.

    Science.gov (United States)

    Owens, Timothy M; Biswas, Pratim

    1996-06-01

    A detailed characterization was performed of the particles produced under various Pb:Si molar feed ratios for a maximum flow reactor temperature of 1000 °C. The silica particles formed in the high temperature region coagulated and only partially coalesced to form large agglomerate structures of high specific surface area. For a lead-only feed, the resulting particles were hydrocerussite with small but detectable amounts of massicot. As the silica precursor was inlet in excess amounts (Pb:Si crystalline lead compounds disappeared and amorphous lead-silica complexes dominated. The particle morphology also changed from cylindrical, polygonal, and spherical shapes to large agglomerate structures composed of several size modes of primary particles. At Pb:Si molar feed ratios of 1:12 and 1:29, the particles making up the chainlike agglomerate structure were primarily spherical, with larger lead silicate spherical particles (=0.5 |im) attached to the agglomerate. The lead was found to be distributed throughout the large agglomerate structures, implying easier capture of lead emissions in particulate control devices.

  16. Role of ammonium ion and transition metals in the formation of secondary organic aerosol and metallo-organic complex within fog processed ambient deliquescent submicron particles collected in central part of Indo-Gangetic Plain.

    Science.gov (United States)

    Singh, Dharmendra Kumar; Gupta, Tarun

    2017-08-01

    In this study we observed the role of ammonium ion (NH4+) and transition metals (Fe, Mn, Cr, and Cu) present in ambient submicron particles in stabilizing and enhancing the yield of water soluble organic carbon (WSOC). A good correlation of WSOC with transition metals and NH4+ was found (R2 = 0.87 and 0.71), respectively within foggy episode collected ambient PM1 (particles having aerodynamic diameter ≤1.0 μm) suggesting plausibleness of alternate oxidation (primarily various carbonyls into their respective organic acids, esters and other derivatives.) and aging mechanisms. Molar concentration of ammonium ion was observed to be exceeded over and above to require in neutralizing the sulphate and nitrate which further hints its role in the neutralization, stabilization and enhancement of subset of WSOC such as water soluble organic acids. Transition metals were further apportioned using enrichment factor analysis. The source of Fe, Mn, and Cr was found to be crustal and Cu was tagged to anthropogenic origin. This study also described the plausible role of significant predictors (Fe and Cu) in the secondary organic aerosol (SOA) formation through effect of Fenton chemistry. Mass-to-charge ratio of identified oxalic acid from our published recent field study (carried out from same sampling location) was used for understanding the possible metallo-organic complex with Fe supports the substantial role of Fe in SOA formation in the deliquescent submicron particles facilitated by aqueous-phase chemistry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Shear effects on aluminum phosphate adjuvant particle properties in vaccine drug products.

    Science.gov (United States)

    Kolade, Olatomirin O; Jin, Wenbin; Tengroth, Charbel; Green, Kenneth D; Bracewell, Daniel G

    2015-02-01

    Adjuvant-containing drug products can be exposed to high levels of interfacial shear during manufacture. This may affect the integrity of the adjuvant, alter its interaction with the drug substance or change the physical characteristics of the drug product. In this study, a solid-liquid interfacial shear device was used to investigate the shear response of aluminum phosphate adjuvant alone and two adjuvant containing vaccine drug products (DP1 and DP2). The relationship between the shear sensitivity of each and its resuspension properties was determined. Changes in the particle dimensions of the bulk adjuvant were minimal at shear strain rates of 10,900 s(-1) . However, at 25,500 s(-1) , the median particle diameter was reduced from 6.2 to 3.5 μm and was marked by the presence of sub-micron fines. A formulation without drug substance and DP2 produced similar shear responses but with less impact on particle diameter. The behavior of DP1 was less predictable. Sheared DP1 was characterized by prolonged sedimentation because of the presence of fine particulates and required in excess of 300 rotations to resuspend after extended storage. The study confirms that the solid-liquid interfacial shear device may be applied to understand product shear sensitivity associated with vaccine manufacturing. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. Inhalable Metal-Rich Air Particles and Histone H3K4 Dimethylation and H3K9 Acetylation in a Cross-sectional Study of Steel Workers

    National Research Council Canada - National Science Library

    Laura Cantone; Francesco Nordio; Lifang Hou; Pietro Apostoli; Matteo Bonzini; Letizia Tarantini; Laura Angelici; Valentina Bollati; Antonella Zanobetti; Joel Schwartz; Pier A. Bertazzi; Andrea Baccarelli

    2011-01-01

    ...) with increased risk of lung cancer. PM contains carcinogenic and toxic metals, including arsenic and nickel, which have been shown in in vitro studies to induce histone modifications that activate gene expression by inducing open-chromatin states...

  19. Wear Particle Atlas. Revised

    Science.gov (United States)

    1982-06-28

    I J?Hf DTIC TAP D Uwnunouncpd □ JUG 11 f i c n 11 on Bv . Di5tril--.it Ion/ Aval Dist Labi lit Avail ’ Epoc y Codes md/or Lai A...other common metal is so colored, with the exception of gold , which is used only in exotic applications. However, other metal particles can display...bit of red oxide is also present, and that category must be included as well. Figure 2.7.2 shows a black oxide particle with gold adhered to it

  20. Self-reported neurological clinical manifestations of metal toxicity in metal-on-metal hip arthroplasty

    NARCIS (Netherlands)

    van Lingen, Christiaan P.; Ettema, Harmen B.; Van Der Straeten, Catherine; Kollen, Bouwdewijn J.; Verheyen, Cees C. P. M.

    2014-01-01

    Adverse reactions to metal particle debris have been increasingly reported as a complication following large head metal-on-metal (MoM) hip arthroplasty. Elevated metal ion levels are a cause for concern. The aim of this study is to evaluate whether exposure to cobalt is associated with patient

  1. Physico-chemical characterization and the in vitro genotoxicity of medical implants metal alloy (TiAlV and CoCrMo) and polyethylene particles in human lymphocytes.

    Science.gov (United States)

    Gajski, Goran; Jelčić, Zelimir; Oreščanin, Višnja; Gerić, Marko; Kollar, Robert; Garaj-Vrhovac, Vera

    2014-01-01

    The main objective of the present study was to investigate chemical composition and possible cyto/genotoxic potential of several medical implant materials commonly used in total hip joint replacement. Medical implant metal alloy (Ti6Al4V and CoCrMo) and high density polyethylene particles were analyzed by energy dispersive X-ray spectrometry while toxicological characterization was done on human lymphocytes using multi-biomarker approach. Energy dispersive X-ray spectrometry showed that none of the elements identified deviate from the chemical composition defined by appropriate ISO standard. Toxicological characterization showed that the tested materials were non-cyto/genotoxic as determined by the comet and cytokinesis-block micronucleus (CBMN) assay. Particle morphology was found (by using scanning electron and optical microscope) as flat, sharp-edged, irregularly shaped fiber-like grains with the mean particle size less than 10µm; this corresponds to the so-called "submicron wear". The very large surface area per wear volume enables high reactivity with surrounding media and cellular elements. Although orthopedic implants proved to be non-cyto/genotoxic, in tested concentration (10μg/ml) there is a constant need for monitoring of patients that have implanted artificial hips or other joints, to minimize the risks of any unwanted health effects. The fractal and multifractal analyses, performed in order to evaluate the degree of particle shape effect, showed that the fractal and multifractal terms are related to the "remnant" level of the particles' toxicity especially with the cell viability (trypan blue method) and total number of nucleoplasmic bridges and nuclear buds as CBMN assay parameters. © 2013.

  2. Particle size distribution of ashes and the behaviour of metals when firing Salix in a circulating fluidized bed boiler (CFB); Askans partikelfraktionsfoerdelning och metallernas beteende vid eldning av Salix i en CFB-panna

    Energy Technology Data Exchange (ETDEWEB)

    Sfiris, G.; Johansson, A. [Vattenfall Utveckling AB, Stockholm (Sweden); Valmari, T.; Kauppinen, E.; Pyykoenen, J.; Lyyraenen, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    1999-07-01

    This project is part of the Ash Recovery Programme aimed at establishing the environmental, technical and financial preconditions for returning wood ash to the forest. The programme is funded jointly by NUTEK, Sydkraft and Vattenfall. This report summarises the results of the experimental and modelling work to study the behaviour of the metals (especially Cd and K), after burning Salix in a 3-12 MW Circulating Fluidized Bed (CFB) boiler. The purpose of the study was to determine, using the experimental data, where cadmium and potassium condense, on what size particles they condense, and the decisive parameters governing these processes. Measurements of the fly ash particle size distribution carried out with a Berner Low Pressure Impactor (BLPI), coupled to a pre-cyclone. Samples were collected from three points: in the convection path at 650 deg C, after the convection path but before the secondary cyclone (160 deg C), and after the bag house (150 deg C). Wet chemical sampling was made for Cd, K, Zn and Pb, with three types of sampling equipment: collection of both particles and gas, collection of particles only, and analysis of the gas phase only. Analysis was made of samples from two places in the convection path (650 deg C and 250 deg C). Samples of bed material, bottom ash and fly ash have been subjected to scanning electron microscopy (SEM), and in addition a few fly ash particles, sampled after the convection path, were subjected to energy dispersive X-ray analysis (EDX). Based on experimental results, modelling work was carried out with an equilibrium model and with a general aerosol computer model ABC (Aerosol Behaviour in Combustion)

  3. A solvent-shrinkage method for producing polymeric microsieves with sub-micron size pores

    NARCIS (Netherlands)

    Vriezekolk, Erik; Kemperman, Antonius J.B.; Girones nogue, Miriam; de Vos, Wiebe Matthijs; Nijmeijer, Dorothea C.

    2013-01-01

    This paper presents a thorough investigation of a simple method to decrease the dimensions of polymeric microsieves. Pore sizes of microsieves are usually in the micrometer scale, but need to be reduced to below 1 µm to make the microsieves attractive for aqueous filtration applications. In this

  4. Trapping ultracold atoms in a sub-micron-period triangular magnetic lattice

    Science.gov (United States)

    Wang, Y.; Tran, T.; Surendran, P.; Herrera, I.; Balcytis, A.; Nissen, D.; Albrecht, M.; Sidorov, A.; Hannaford, P.

    2017-07-01

    We report the trapping of ultracold 87Rb atoms in a 0.7-μ m-period two-dimensional triangular magnetic lattice on an atom chip. The magnetic lattice is created by a lithographically patterned magnetic Co/Pd multilayer film plus bias fields. Rubidium atoms in the |F =1 , mF=-1 > low-field seeking state are trapped at estimated distances down to about 100 nm from the chip surface and with calculated mean trapping frequencies up to about 800 kHz . The measured lifetimes of the atoms trapped in the magnetic lattice are in the range 0.4-1.7 ms , depending on distance from the chip surface. Model calculations suggest the trap lifetimes are currently limited mainly by losses due to one-dimensional thermal evaporation following loading of the atoms from the Z -wire trap into the very tight magnetic lattice traps, rather than by fundamental loss processes such as surface interactions, three-body recombination, or spin flips due to Johnson magnetic noise. The trapping of atoms in a 0.7 -μ m -period magnetic lattice represents a significant step toward using magnetic lattices for quantum tunneling experiments and to simulate condensed matter and many-body phenomena in nontrivial lattice geometries.

  5. Induced magnetoresistance in semiconductor devices due to single sub-micron magnetic barriers

    Science.gov (United States)

    Kubrak, V.; Rahman, F.; Overend, N.; Gallagher, B. L.; Main, P. C.; Boeck, J. de; Behest, M.; Marrows, C. H.; Howson, M. A.

    1998-12-01

    We investigate the magnetoresistance induced in a near-surface two-dimensional electron gas by the fringe field of a thin ferromagnetic line on the surface of the device. From the measured magnetoresistance, we deduce the hysteretic properties of the magnetic line, using the semiconductor device as a nanomagnetometer.

  6. Multidisciplinary Approach to the Science and Technology of Sub-Micron Electronics.

    Science.gov (United States)

    1987-03-10

    overlap with the continuum are unique to the quantum well structures. A paper describing our findings has been submitted for publication. Regarding...Grant ARO DAAG 29-83-K-0131 during the period 7/1/85-12/31/85 1. " Fibonacci GaAs-AlAs Superlattices", R. Clarke, R. Merlin, K. Bajema, F.-Y Juang and P.K...pursued: experiments on new quasiperiodic superlattices and studies of quantum-well structures. In the quasiperiodic ( Fibonacci ) superlattices we have

  7. Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

    Directory of Open Access Journals (Sweden)

    D. Rosenfeld

    2007-07-01

    Full Text Available The feasibility of hurricane modification was investigated for hurricane Katrina using the Weather Research and Forecasting Model (WRF. The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning–off" warm rain formation in the clouds at Katrina's periphery (where wind speeds were less than 22 m s−1. This simplification of the simulation of aerosol effects is aimed at evaluating the largest possible response. This resulted in the weakening of the hurricane surface winds compared to the "non-seeded" simulated storm during the first 24 h within the entire tropical cyclone (TC area compared to a control simulation without warm rain suppression. Later, the seeding-induced evaporative cooling at the TC periphery led to a shrinking of the eye and hence to some increase in the wind within the small central area of the TC. Yet, the overall strength of the hurricane, as defined by the area covered by hurricane force winds, decreased in response to the suppressed warm rain at the periphery, as measured by a 25% reduction in the radius of hurricane force winds. In a simulation with warm rain suppression throughout the hurricane, the radius of the hurricane force winds was reduced by more than 42%, and although the diameter of the eye shrunk even further the maximum winds weakened. This shows that the main mechanism by which suppressing warm rain weakens the TC is the low level evaporative cooling of the un-precipitated cloud drops and the added cooling due to melting of precipitation that falls from above.

  8. Sub-micron-sized delafossite CuCrO2 with different morphologies ...

    Indian Academy of Sciences (India)

    Currently, copper chromium oxide crystallizing in delafossite structure attracts huge research interest due to its versatile applications arising from its layered structure. In this work, delafossite CuCrO 2 was synthesized by sol–gel method from their respective hydrated nitrate salts with citric acid as a chelating agent.

  9. Penetration of sub-micron aerosol droplets in composite cylindrical filtration elements

    NARCIS (Netherlands)

    Geurts, Bernardus J.; Pratte, Pascal; Stolz, S.; Stabbert, Regina; Poux, Valerie; Nordlund, Markus; Winkelmann, Christoph

    Advection–diffusion transport of aerosol droplets in composite cylindrical filtration elements is analyzed and compared to experimental data. The penetration, characterizing the fraction of droplets that passes through the pores of a filtration element, is quantified for a range of flow rates. The

  10. Deviation from threshold model in ultrafast laser ablation of graphene at sub-micron scale

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Villalba, A.; Xie, C.; Salut, R.; Furfaro, L.; Giust, R.; Jacquot, M.; Lacourt, P. A.; Dudley, J. M.; Courvoisier, F., E-mail: francois.courvoisier@femto-st.fr [Institut FEMTO-ST, UMR 6174 CNRS, Universite de Bourgogne Franche-Comte, 25030 Besançon Cedex (France)

    2015-08-10

    We investigate a method to measure ultrafast laser ablation threshold with respect to spot size. We use structured complex beams to generate a pattern of craters in CVD graphene with a single laser pulse. A direct comparison between beam profile and SEM characterization allows us to determine the dependence of ablation probability on spot-size, for crater diameters ranging between 700 nm and 2.5 μm. We report a drastic decrease of ablation probability when the crater diameter is below 1 μm which we interpret in terms of free-carrier diffusion.

  11. White light generation using photonic crystal fiber with sub-micron circular lattice

    Science.gov (United States)

    Saghaei, Hamed; Ghanbari, Ashkan

    2017-08-01

    In this paper, we study a photonic crystal fiber (PCF) with circular lattice and engineer linear and nonlinear parameters by varying the diameter of air-holes. It helps us obtain low and high zero dispersion wavelengths in the visible and nearinfrared regions. We numerically demonstrate that by launching 100 fs input pulses of 1, 2, and 5 kW peak powers with center wavelength of 532 nm from an unamplified Ti:sapphire laser into a 100 mm length of the engineered PCF, supercontinua as wide as 290, 440 and 830 nm can be obtained, respectively. The spectral broadening is due to the combined action of self-phase modulation, stimulated Raman scattering and parametric four-wave-mixing generation of the pump pulses. The third and the widest spectrum covers the entire visible range and a part of near infrared region making it a suitable source for both white light applications and optical coherence tomography to measure retinal oxygen metabolic response to systemic oxygenation.

  12. Laser forming for sub-micron adjustment: with application to optical fiber assembly

    NARCIS (Netherlands)

    Folkersma, Ger

    2015-01-01

    Laser forming is a method to deform a material by controlled local laser heating. In combination with a dedicated actuator topology, those deformations can be used for high precision alignment of components. This thesis applies this method to the alignment of optical fibers with respect to the

  13. OpenStage: a low-cost motorized microscope stage with sub-micron positioning accuracy.

    Directory of Open Access Journals (Sweden)

    Robert A A Campbell

    Full Text Available Recent progress in intracellular calcium sensors and other fluorophores has promoted the widespread adoption of functional optical imaging in the life sciences. Home-built multiphoton microscopes are easy to build, highly customizable, and cost effective. For many imaging applications a 3-axis motorized stage is critical, but commercially available motorization hardware (motorized translators, controller boxes, etc are often very expensive. Furthermore, the firmware on commercial motor controllers cannot easily be altered and is not usually designed with a microscope stage in mind. Here we describe an open-source motorization solution that is simple to construct, yet far cheaper and more customizable than commercial offerings. The cost of the controller and motorization hardware are under $1000. Hardware costs are kept low by replacing linear actuators with high quality stepper motors. Electronics are assembled from commonly available hobby components, which are easy to work with. Here we describe assembly of the system and quantify the positioning accuracy of all three axes. We obtain positioning repeatability of the order of 1 μm in X/Y and 0.1 μm in Z. A hand-held control-pad allows the user to direct stage motion precisely over a wide range of speeds (10(-1 to 10(2 μm·s(-1, rapidly store and return to different locations, and execute "jumps" of a fixed size. In addition, the system can be controlled from a PC serial port. Our "OpenStage" controller is sufficiently flexible that it could be used to drive other devices, such as micro-manipulators, with minimal modifications.

  14. OpenStage: a low-cost motorized microscope stage with sub-micron positioning accuracy.

    Science.gov (United States)

    Campbell, Robert A A; Eifert, Robert W; Turner, Glenn C

    2014-01-01

    Recent progress in intracellular calcium sensors and other fluorophores has promoted the widespread adoption of functional optical imaging in the life sciences. Home-built multiphoton microscopes are easy to build, highly customizable, and cost effective. For many imaging applications a 3-axis motorized stage is critical, but commercially available motorization hardware (motorized translators, controller boxes, etc) are often very expensive. Furthermore, the firmware on commercial motor controllers cannot easily be altered and is not usually designed with a microscope stage in mind. Here we describe an open-source motorization solution that is simple to construct, yet far cheaper and more customizable than commercial offerings. The cost of the controller and motorization hardware are under $1000. Hardware costs are kept low by replacing linear actuators with high quality stepper motors. Electronics are assembled from commonly available hobby components, which are easy to work with. Here we describe assembly of the system and quantify the positioning accuracy of all three axes. We obtain positioning repeatability of the order of 1 μm in X/Y and 0.1 μm in Z. A hand-held control-pad allows the user to direct stage motion precisely over a wide range of speeds (10(-1) to 10(2) μm·s(-1)), rapidly store and return to different locations, and execute "jumps" of a fixed size. In addition, the system can be controlled from a PC serial port. Our "OpenStage" controller is sufficiently flexible that it could be used to drive other devices, such as micro-manipulators, with minimal modifications.

  15. Analysis and Test Development for Parasitic Fails in Deep Sub-Micron Memory Devices

    NARCIS (Netherlands)

    Irobi, I.S.

    2011-01-01

    Emerging technology trends are gravitating towards extremely high levels of integration at the package and chip levels, and use of deeply scaled technology in nanometer, approaching 10nm CMOS. Challenges will arise due to the ability to design complex systems such as robots that encompass sensors,

  16. Enhanced strength and temperature dependence of mechanical properties of Li at small length scales and its implications for Li metal anodes

    CERN Document Server

    and, Chen Xu; Aryanfar, Asghar; Viswanathan, Venkatasubramanian; Greer, Julia R

    2016-01-01

    Most next-generation Li-ion battery chemistries require a functioning lithium metal (Li) anode. However, its application in secondary batteries has been inhibited because of uncontrollable dendrite growth during cycling. Mechanical suppression of dendrite growth through solid polymer electrolytes (SPE) or through robust separators has shown the most potential for alleviating this problem. Studies of the mechanical behavior of Li at any length scale and temperature are virtually non-existent because of its extreme reactivity, which renders sample preparation, transfer, microstructure characterization and mechanical testing prohibitively challenging. We conduct nano-mechanical experiments in an in-situ Scanning Electron Microscope and show that micron-sized Li attains extremely high strengths of 105 MPa at room temperature and of 35MPa at 90$^\\circ$C. We demonstrate that single crystalline Li exhibits a power-law size-effect at the micron- and sub-micron length scales, with the strengthening exponent of -0.68 a...

  17. Chemical partitioning of fine particle-bound metals on haze-fog and non-haze-fog days in Nanjing, China and its contribution to human health risks

    Science.gov (United States)

    Li, Huiming; Wu, Hongfei; Wang, Qin'geng; Yang, Meng; Li, Fengying; Sun, Yixuan; Qian, Xin; Wang, Jinhua; Wang, Cheng

    2017-01-01

    Information on chemical partitioning and associated risk of airborne metals, particularly during a haze-fog episode, is limited. Fine particulate matter (PM2.5) was collected during a severe haze-fog event in winter and non-haze-fog periods in summer and fall from an urban region of a typical Chinese mega-city, Nanjing. The particulate-bound metals (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sr, Ti, V, and Zn) were chemically fractionated in a four-step sequential extraction procedure and human health risk was assessed. During the haze-fog episode, PM2.5 was extremely elevated with a mean concentration of 281 μg/m3 (range: 77-431 μg/m3), whereas the mean PM2.5 concentrations in summer and fall periods were 86 μg/m3 (range: 66-111 μg/m3) and 77 μg/m3 (range: 42-131 μg/m3), respectively. All elements had significantly higher concentrations and many metals exceeded relevant limits on haze-fog days. K, Na, Sr, Zn, Mo, Ca, Cd, Mg, Mn, Cu, Ba, Cr and As all showed relatively high proportions of the soluble and exchangeable fraction and strong bio-accessible potential. High temperature and humidity may increase the bio-accessible fraction of many airborne metals. The hazard index for potential toxic metals was 0.115, which was lower than the safe limit (1). However, the combined carcinogenic risk was 1.32 × 10- 6 for children and 5.29 × 10- 6 for adults, with both values being higher than the precautionary criterion (10- 6). Results of this study provide information for the behavior and risk mitigation of airborne metals.

  18. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    Science.gov (United States)

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  19. Characteristics of trace metals in fine (PM2.5) and inhalable (PM10) particles and its health risk assessment along with in-silico approach in indoor environment of India

    Science.gov (United States)

    Satsangi, P. Gursumeeran; Yadav, Suman; Pipal, Atar Singh; Kumbhar, Navanath

    2014-08-01

    Indoor concentrations of fine (PM2.5: aerodynamic diameter ≤ 2.5) and inhalable (PM10: aerodynamic diameter ≤ 10 μm) particles and its associated toxic metals are of concern now-a-days due to its effects on human health and environment. PM10 and PM2.5 samples were collected from indoor microenvironments on glass fiber and PTFE filter paper using low volume air sampler in Pune. The average concentration of PM2.5 and PM10 were 89.7 ± 43.2 μg m-3 and 138.2 ± 68.2 μg m-3 at urban site while it was 197.5 ± 84.3 and 287 ± 92 μg m-3 at rural site. Trace metals such as Cd, Co, Cr, Cu, Fe, Mn, Pb, Sb and Zn in particulate matter were estimated by ICP-AES. Concentrations of crustal metals were found to be higher than the carcinogenic metals in both the microenvironments. On the contrary the soluble and bio-availability fraction of carcinogenic metals were found higher thus it may cause the higher risk to human health. Therefore, cancer risk assessment of carcinogenic metals; Cr, Ni and Cd was calculated. Among the carcinogenic metals, Ni showed highest cancer risk in indoor PM. The higher cancer risk assessment of Ni has been supported by In-silico study which suggested that Ni actively formed co-ordination complex with histone proteins (i.e. H3-Ni/H4-Ni) by maintaining strong hydrogen bonding interactions with Asp and Glu residues of nucleosomal proteins. Present In-silico study of Ni-histone complexes will help to emphasize the possible role of Asp and Glu residues in DNA methylation, deacetylation and ubiquitinations of nucleosomal proteins. Hence, this study could pave the way to understand the structural consequence of Ni in nucleosomal proteins and its impact on epigenetic changes which ultimately cause lung and nasal cancer.

  20. On the role of metal particle size and surface coverage for photo-catalytic hydrogen production; a case study of the Au/CdS system

    KAUST Repository

    Majeed, I.

    2015-09-25

    Photo-catalytic hydrogen production has been studied on Au supported CdS catalysts under visible light irradiation in order to understand the effect of Au particle size as well as the reaction medium properties. Au nanoparticles of size about 2-5 nm were deposited over hexagonal CdS particles using a new simple method involving reduction of Au3+ ions with iodide ions. Within the investigated range of Au (between 1 and 5 wt. %) fresh particles with mean size of 4 nm and XPS Au4f/Cd3d surface ratio of 0.07 showed the highest performance (ca. 1 molecule of H2 / Auatom s−1) under visible light irradiation (>420 nm and a flux of 35 mW/cm2). The highest hydrogen production rate was obtained from water (92%)-ethanol (8%) in an electrolyte medium (Na2S-Na2SO3). TEM studies of fresh and used catalysts showed that Au particle size increases (almost 5 fold) with increasing photo-irradiation time due to photo-agglomeration effect yet no sign of deactivation was observed. A mechanism for hydrogen production from ethanol-water electrolyte mixture is presented and discussed.

  1. Polygamous particles

    OpenAIRE

    Wu, Kun-Ta; Feng, Lang; Sha, Ruojie; Dreyfus, Rémi; Grosberg, Alexander Y.; Seeman, Nadrian C.; Chaikin, Paul M.

    2012-01-01

    DNA is increasingly used as an important tool in programming the self-assembly of micrometer- and nanometer-scale particles. This is largely due to the highly specific thermoreversible interaction of cDNA strands, which, when placed on different particles, have been used to bind precise pairs in aggregates and crystals. However, DNA functionalized particles will only reach their true potential for particle assembly when each particle can address and bind to many different kinds of particles. ...

  2. Metal nanoparticle inks

    Science.gov (United States)

    Lewis, Jennifer A [Urbana, IL; Ahn, Bok Yeop [Champaign, IL; Duoss, Eric B [Urbana, IL

    2011-04-12

    Stabilized silver particles comprise particles comprising silver, a short-chain capping agent adsorbed on the particles, and a long-chain capping agent adsorbed on the particles. The short-chain capping agent is a first anionic polyelectrolyte having a molecular weight (Mw) of at most 10,000, and the long-chain capping agent is a second anionic polyelectrolyte having a molecular weight (Mw) of at least 25,000. The stabilized silver particles have a solid loading of metallic silver of at least 50 wt %.

  3. Gold ions bio-released from metallic gold particles reduce inflammation and apoptosis and increase the regenerative responses in focal brain injury

    DEFF Research Database (Denmark)

    Larsen, Agnete; Kolind, Kristian; Pedersen, Dan Sonne

    2008-01-01

    Traumatic brain injury results in loss of neurons caused as much by the resulting neuroinflammation as by the injury. Gold salts are known to be immunosuppressive, but their use are limited by nephrotoxicity. However, as we have proven that implants of pure metallic gold release gold ions which d...... a completely new medical concept that bypasses the blood-brain-barrier and allows direct drug delivery to inflamed brain tissue....

  4. Intracrystalline diffusion in metal organic framework during heterogeneous catalysis: influence of particle size on the activity of MIL-100 (Fe) for oxidation reactions.

    Science.gov (United States)

    Dhakshinamoorthy, Amarajothi; Alvaro, Mercedes; Hwang, Young Kyu; Seo, You-Kyong; Corma, Avelino; Garcia, Hermenegildo

    2011-10-28

    Three MIL-100 (Fe) samples differing in average crystal size (from 60-70 to >400 nm) have been synthesized by microwave heating using three HF/Fe(3+) ratios. Oxidation of diphenylmethane with tert-butylhydroperoxide (TBHP) and thiophenol with oxygen are catalyzed by three MIL-100 (Fe) samples with similar reaction rates regardless of its average particle size. In contrast, the activity of the three MIL-100 (Fe) samples for the oxidation of bulky triphenylmethane by TBHP largely depends on the average crystal size of the sample: the smaller the average particle size, the larger the initial reaction rate of triphenylmethane oxidation. These results show that diffusion limitation takes place on MOF catalysis depending on the substrate size and provides indirect evidence that these reactions take place inside the intracrystalline space of the porous catalysts.

  5. Identification of metals into fine particles (PM{sub 2.5}) during the dry cold season in the Toluca City; Identificacion de metales en particulas finas (PM{sub 2.5}) durante la epoca seca-fria en la ciudad de Toluca

    Energy Technology Data Exchange (ETDEWEB)

    Martinez P, A. A. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Tollocan esquina Paseo Colon s/n, Toluca 50180, Estado de Mexico (Mexico); Aldape U, F. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2008-07-01

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

  6. Application of 'direct' beta particle excitation for the determination of noble metals in catalysts by radioisotope excited X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    LaBrecque, J.J.; Rosales, P.A.; Quiero, A. (Instituto Venezolano de Investigaciones Cientificas, Caracas)

    1982-01-01

    A new technique was applied for exciting X-rays for X-ray fluorescence analysis by 'direct' beta excitation for the determination of noble metals in catalytic materials. A series of five synthetic standards were prepared each for platinum and palladium in the range of 0.5-10% for both carbon and alumina supports. The X-ray spectrometer system employed was a modified TN-11 and /sup 147/Pm inserted directly in the sample itself acts as the excitation source. The detector was a high resolution Si(Li) semiconductor with better than 160 eV resolution.

  7. Thin Metallic Films from Solvated Metal Atoms.

    Science.gov (United States)

    1987-07-14

    research has developed over the past two decades that deals with the generation of atoms of metals (by metal evaporation, and the interaction of these...Departamento de Quimica , Universidad de Concepcion, Cassilla 3-:, c oncepcion, Chile. -I{ - ~ *~.’JS*~M 4 .~4\\ 821 19 the gold particles were negatively...flocculation were observed, as shown in table a Generally about 0.1 g In was Suspended in 100-200 nl solvent. Several approacies to characterization of

  8. Functional characterisation of metal(loid) processes in planta through the integration of synchrotron techniques and plant molecular biology

    Science.gov (United States)

    Donner, Erica; Punshon, Tracy; Guerinot, Mary Lou; Lombi, Enzo

    2013-01-01

    Functional characterisation of the genes regulating metal(loid) homeostasis in plants is a major focus of crop biofortification, phytoremediation, and food security research. This paper focuses on the potential for advancing plant metal(loid) research by combining molecular biology and synchrotron-based techniques. Recent advances in x-ray focussing optics and fluorescence detection have greatly improved the potential of synchrotron techniques for plant science research, allowing metal(loids) to be imaged in vivo in hydrated plant tissues at sub-micron resolution. Laterally resolved metal(loid) speciation can also be determined. By using molecular techniques to probe the location of gene expression and protein localisation and combining it with this synchrotron-derived data, functional information can be effectively and efficiently assigned to specific genes. This paper provides a review of the state of the art in this field, and provides examples as to how synchrotron-based methods can be combined with molecular techniques to facilitate functional characterisation of genes in planta. PMID:22200921

  9. Application of colloidal chemistry in aqueous phase to the preparation of supported metallic catalysts: particles size and aggregation control; Application de la chimie colloidale en phase aqueuse a la preparation de catalyseurs metalliques supportes: controle de la taille et de l`etat d`agregation des particules

    Energy Technology Data Exchange (ETDEWEB)

    Pages, T.

    1998-09-16

    This work is an application of colloidal chemistry in aqueous phase on supported metal catalyst preparation. The objective is the control of particle size and aggregation. The preparation of the materials was achieved in two steps: - the synthesis of PdO hydrosols was obtained by two ways: neutralisation of the solution containing metallic salt by adding alkaline solution or by thermo-hydrolysis; the sols were then deposited on carriers (Al{sub 2}O{sub 3}, SIO{sub 2}). The use of partial charge model allowed us to determine the complexes that were able to generate PdO. The preparation of PdO from Pd(H{sub 2}O){sub 4}{sup 2+} was studied and a mechanism of oxide formation was elaborated. The neutralisation of Pd(H{sub 2}O){sub 4}{sup 2+} obtained by adding alkaline solution led to particles with an average size of 1.8 nm and a narrow particle size distribution. Only the thermo-hydrolysis of Pd(H{sub 2}O){sub 4}{sup 2+} led to particles which size is higher than 3.0 nm. In the last case, particle size is controlled by the precursor concentration (Pd(H{sub 2}O){sub 2}(OH){sub 2}) generated in the medium. We have demonstrated that particle aggregation in the sol depends on the Ph and the way of preparation. It can be controlled by adding complexing anions (Cl{sup -}, NO{sub 2}{sup -}). Concerning the deposition of sols on carriers, it led to isolated or aggregated particles according to experimental conditions. Particle size was not modified during the deposition. Moreover, in our experimental conditions, reduction of particles did not modify particle size and aggregation. An application of this original way of preparation on catalysis allowed us to demonstrate the interest of controlling particle size and aggregation. (author) 186 refs.

  10. Dyeing fabrics with metals

    Science.gov (United States)

    Kalivas, Georgia

    2002-06-01

    Traditionally, in textile dyeing, metals have been used as mordants or to improve the color produced by a natural or synthetic dye. In biomedical research and clinical diagnostics gold colloids are used as sensitive signals to detect the presence of pathogens. It has been observed that when metals are finely divided, a distinct color may result that is different from the color of the metal in bulk. For example, when gold is finely divided it may appear black, ruby or purple. This can be seen in biomedical research when gold colloids are reduced to micro-particles. Bright color signals are produced by few nanometer-sized particles. Dr. William Todd, a researcher in the Department of Veterinary Science at the Louisiana State University, developed a method of dyeing fabrics with metals. By using a reagent to bond the metal particles deep into the textile fibers and actually making the metal a part of the chemistry of the fiber. The chemicals of the fabric influence the resulting color. The combination of the element itself, the size of the particle, the chemical nature of the particle and the interaction of the metal with the chemistry of the fabric determine the actual hue. By using different elements, reagents, textiles and solvents a broad range of reproducible colors and tones can be created. Metals can also be combined into alloys, which will produce a variety of colors. The students of the ISCC chapter at the Fashion Institute of Technology dyed fabric using Dr. Todd's method and created a presentation of the results. They also did a demonstration of dyeing fabrics with metals.

  11. Spin-phonon coupling in rod-shaped half-metallic CrO sub 2 ultrafine particles: a magnetic Raman scattering study

    CERN Document Server

    Yu, T; Sun, W X; Lin, J Y; Ding, J

    2003-01-01

    Half-metallic CrO sub 2 powder compact with rod-shaped nanoparticles was studied by micro-Raman scattering in the presence of an external magnetic field at room temperature (300 K). In the low-field region (H <= 250 mT), the frequency and intensity of the E sub g mode, an internal phonon mode of CrO sub 2 , increase dramatically with increase in the magnetic field, while the corresponding linewidth decreases. The above parameters become constant when the CrO sub 2 powder enters the saturation state at higher magnetic field. The pronounced anomalies of the Raman phonon parameters under a low magnetic field are attributed to the spin-phonon coupling enhanced by the magnetic ordering, which is induced by the external magnetic field. (letter to the editor)

  12. Field isotopic study of lead fate and compartmentalization in earthworm-soil-metal particle systems for highly polluted soil near Pb recycling factory.

    Science.gov (United States)

    Goix, Sylvaine; Mombo, Stéphane; Schreck, Eva; Pierart, Antoine; Lévêque, Thibaut; Deola, Frédéric; Dumat, Camille

    2015-11-01

    Earthworms are important organisms in soil macrofauna and play a key role in soil functionality, and consequently in terrestrial ecotoxicological risk assessments. Because they are frequently observed in soils strongly polluted by metals, the influence of earthworm bioturbation on Pb fate could therefore be studied through the use of Pb isotopes. Total Pb concentrations and isotopic composition ((206)Pb, (207)Pb and (208)Pb) were then measured in earthworms, casts and bulk soils sampled at different distance from a lead recycling factory. Results showed decreasing Pb concentrations with the distance from the factory whatever the considered matrix (bulk soils, earthworm bodies or cast samples) with higher concentrations in bulk soils than in cast samples. The bivariate plot (208)Pb/(206)Pb ratios versus (206)Pb/(207)Pb ratios showed that all samples can be considered as a linear mixing between metallic process particulate matter (PM) and geochemical Pb background. Calculated anthropogenic fraction of Pb varied between approximately 84% and 100%. Based on Pb isotopic signatures, the comparison between casts, earthworms and bulk soils allowed to conclude that earthworms preferentially ingest the anthropogenic lead fraction associated with coarse soil organic matter. Actually, soil organic matter was better correlated with Pb isotopic ratios than with Pb content in soils. The proposed hypothesis is therefore a decrease of soil organic matter turnover due to Pb pollution with consequences on Pb distribution in soils and earthworm exposure. Finally, Pb isotopes analysis constitutes an efficient tool to study the influence of earthworm bioturbation on Pb cycle in polluted soils. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Microchip Coulter particle counter

    DEFF Research Database (Denmark)

    Larsen, Ulrik Darling; Blankenstein, Gert; Branebjerg, J.

    1997-01-01

    and short contact time of liquids in microchannels. As a result, the width of the liquids can be controlled without knowing the actual flow rates. The μCPC has been fabricated by standard microfabrication techniques, including RIE, wet silicon etching, metalization and anodic bonding......This paper presents a micro device employing the Coulter principle for counting and sizing of living cells and particles in liquid suspension. The microchip Coulter particle counter (μCPC) has been employed in a planar silicon structure covered with glass, which enables detailed observation during...

  14. Particle detectors

    CERN Multimedia

    CERN. Geneva

    1999-01-01

    Introduction, interaction of radiation with matter measurement of momentum of charged particles, of energy of e/gamma, hadrons, identification of particles. Design of HEP detectors. Principle of operation and performance of tracking sub-detectors, calorimeters and muon system.

  15. Uniform surface modification of 3D Bioglass®-based scaffolds with mesoporous silica particles (MCM-41 for enhancing drug uptake capability

    Directory of Open Access Journals (Sweden)

    Elena eBoccardi

    2015-11-01

    Full Text Available The design and characterization of a new family of multifunctional scaffolds based on bioactive glass (BG of 45S5 composition for bone tissue engineering and drug delivery applications is presented. These BG-based scaffolds are developed via a replication method of polyurethane packaging foam. In order to increase the therapeutic functionality, the scaffolds were coated with mesoporous silica particles (MCM-41, which act as an in-situ drug delivery system. These sub-micron spheres are characterized by large surface area and pore volume with a narrow pore diameter distribution. The solution used for the synthesis of the silica mesoporous particles was designed to obtain at the same time a high ordered mesoporous structure and spherical shape, both are key factors for achieving the desired controlled drug release. The MCM-41 particles were synthesized directly inside the BG-based scaffolds and the drug release capability of this combined system was evaluated. Moreover the effect of MCM-41 particle coating on the bioactivity of the BG-based scaffolds was assessed. The results indicate that it is possible to obtain a multifunctional scaffold system characterized by high and interconnected porosity, high bioactivity and sustained drug delivery capability.

  16. Magnetic Properties of Nanometer-sized Crystalline and Amorphous Particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Bødker, Franz; Hansen, Mikkel Fougt

    1997-01-01

    are superparamagnetic at finite temperatures. The temperature dependence of the superparamagnetic relaxation time and the influence of inter-particle interactions is discussed. Finally, some examples of studies of surface magnetization of alpha-Fe particles are presented.......Amorphous transition metal-metalloid alloy particles can be prepared by chemical preparation techniques. We discuss the preparation of transition metal-boron and iron-carbon particles and their magnetic properties. Nanometer-sized particles of both crystalline and amorphous magnetic materials...

  17. Photocatalytic and Adsorption Performances of Faceted Cuprous Oxide (Cu₂O) Particles for the Removal of Methyl Orange (MO) from Aqueous Media.

    Science.gov (United States)

    Ho, Weng Chye Jeffrey; Tay, Qiuling; Qi, Huan; Huang, Zhaohong; Li, Jiao; Chen, Zhong

    2017-04-23

    Particles of sub-micron size possess significant capacity to adsorb organic molecules from aqueous media. Semiconductor photocatalysts in particle form could potentially be utilized for dye removal through either physical adsorption or photo-induced chemical process. The photocatalytic and adsorption capabilities of Cu₂O particles with various exposed crystal facets have been studied through separate adsorption capacity test and photocatalytic degradation test. These crystals display unique cubic, octahedral, rhombic dodecahedral, and truncated polyhedral shapes due to specifically exposed crystal facet(s). For comparison, Cu₂O particles with no clear exposed facets were also prepared. The current work confirms that the surface charge critically affects the adsorption performance of the synthesized Cu₂O particles. The octahedral shaped Cu₂O particles, with exposed {111} facets, possess the best adsorption capability of methyl orange (MO) dye due to the strongest positive surface charge among the different types of particles. In addition, we also found that the adsorption of MO follows the Langmuir monolayer mechanism. The octahedral particles also performed the best in photocatalytic dye degradation of MO under visible light irradiation because of the assistance from dye absorption. On top of the photocatalytic study, the stability of these Cu₂O particles during the photocatalytic processes was also investigated. Cu(OH)₂ and CuO are the likely corrosion products found on the particle surface after the photocorrosion in MO solution. By adding hole scavengers in the solution, the photocorrosion of Cu₂O was greatly reduced. This observation confirms that the photocatalytically generated holes were responsible for the photocorrosion of Cu₂O.

  18. Deformation Behavior of Nanoporous Metals

    Energy Technology Data Exchange (ETDEWEB)

    Biener, J; Hodge, A M; Hamza, A V

    2007-11-28

    of free surfaces can no longer be neglected. As the material becomes more and more constraint by the presence of free surfaces, length scale effects on plasticity become more and more important and bulk properties can no longer be used to describe the material properties. Even the elastic properties may be affected as the reduced coordination of surface atoms and the concomitant redistribution of electrons may soften or stiffen the material. If, and to what extend, such length scale effects control the mechanical behavior of nanoporous materials depends strongly on the material and the characteristic length scale associated with its plastic deformation. For example, ductile materials such as metals which deform via dislocation-mediated processes can be expected to exhibit pronounced length scale effects in the sub-micron regime where free surfaces start to constrain efficient dislocation multiplication. In this chapter we will limit our discussion to our own area of expertise which is the mechanical behavior of nanoporous open-cell gold foams as a typical example of nanoporous metal foams. Throughout this chapter we will review our current understanding of the mechanical properties of nanoporous open-cell foams including both experimental and theoretical studies.

  19. Comparative study of energy of particles ejected from coulomb explosion of rare gas and metallic clusters irradiated by intense femtosecond laser field

    Science.gov (United States)

    Boucerredj, N.; Beggas, K.

    2016-10-01

    We present our study of high intensity femtosecond laser field interaction with large cluster of Kr and Na (contained 2.103 to 2.107 atoms). When laser intensity is above a critical value, it blows off all of electrons from the cluster and forms a non neutral ion cloud. The irradiation of these clusters by the intense laser field leads to highly excitation energy which can be the source of energetic electrons, electronic emission, highly charge, energetic ions and fragmentation process. During the Coulomb explosion of the resulting highly ionized, high temperature nanoplasma, ions acquire again their energy. It is shown that ultra fast ions are produced. The goal of our study is to investigate in detail a comparative study of the expansion and explosion then the ion energy of metallic and rare gas clusters irradiated by an intense femtosecond laser field. We have found that ions have a kinetic energy up to 105 eV and the Coulomb pressure is little than the hydrodynamic pressure. The Coulomb explosion of a cluster may provide a new high energy ion source.

  20. Deposition Profile Analysis from DIII-D Metal Rings Campaign Outer-Midplane Collector Probe Diagnostic and Utilization of Enriched Isotopic Tungsten Tracer Particles

    Science.gov (United States)

    Donovan, D. C.; Duran, J.; Zamperini, S.; Lee, S.; Unterberg, E. A.; Wampler, W. R.; Rudakov, D. L.; Elder, D.; Stangeby, P. C.; Abrams, T.

    2017-10-01

    The DIII-D Metal Rings Campaign used isotopically-enriched, W-coated divertor tiles coupled with dual-facing midplane collector probes (CPs) in the far Scrape-off Layer (SOL). Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) results are presented characterizing the isotopic ratios of deposited W on the CPs and which give quantitative information on the transport of W from specific poloidal locations within the lower outer divertor region having different isotopically-marked tiles. Rutherford Backscattering Spectrometry (RBS) of these CPs has provided areal densities of elemental W content. These resultant W deposition profiles were compared with DIVIMP modelling of the far-SOL to better understand impurity transport in the edge plasma. CPs were exposed for 37 distinct operating configurations (L-mode/H-mode, forward/reverse Bt, strikepoint position). Radial decay lengths (RDL) between 5 and 50 mm were observed with consistently narrower RDL and higher peak W content on the side of the probes connected along field lines to the inner divertor, indicating a concentration of W in the upstream plasma. Correlations are discussed between peak W content, RDL, and isotopic profiles on the CPs over a wide range of conditions. Work supported by US DOE under DE-AC05-00OR22725, DE-FG02-07ER54917, DE-FC02-04ER54698, DE-NA0003525.

  1. Radiopure Metal-Loaded Liquid Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Rosero, Richard [Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.; Yeh, Minfang [Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.

    2015-03-18

    Metal-loaded liquid scintillator plays a key role in particle and nuclear physics experiments. The applications of metal ions in various neutrino experiments and the purification methods for different scintillator components are discussed in this paper.

  2. Polygamous particles.

    Science.gov (United States)

    Wu, Kun-Ta; Feng, Lang; Sha, Ruojie; Dreyfus, Rémi; Grosberg, Alexander Y; Seeman, Nadrian C; Chaikin, Paul M

    2012-11-13

    DNA is increasingly used as an important tool in programming the self-assembly of micrometer- and nanometer-scale particles. This is largely due to the highly specific thermoreversible interaction of cDNA strands, which, when placed on different particles, have been used to bind precise pairs in aggregates and crystals. However, DNA functionalized particles will only reach their true potential for particle assembly when each particle can address and bind to many different kinds of particles. Indeed, specifying all bonds can force a particular designed structure. In this paper, we present the design rules for multiflavored particles and show that a single particle, DNA functionalized with many different "flavors," can recognize and bind specifically to many different partners. We investigate the cost of increasing the number of flavors in terms of the reduction in binding energy and melting temperature. We find that a single 2-μm colloidal particle can bind to 40 different types of particles in an easily accessible time and temperature regime. The practical limit of ∼100 is set by entropic costs for particles to align complementary pairs and, surprisingly, by the limited number of distinct "useful" DNA sequences that prohibit subunits with nonspecific binding. For our 11 base "sticky ends," the limit is 73 distinct sequences with no unwanted overlaps of 5 bp or more. As an example of phenomena enabled by polygamous particles, we demonstrate a three-particle system that forms a fluid of isolated clusters when cooled slowly and an elastic gel network when quenched.

  3. Quantification and localization of trace metals in natural plancton using a synchrotron x-ray fluorescence microprobe.

    Energy Technology Data Exchange (ETDEWEB)

    Twining, B. S.; Baines, S. B.; Fisher, N. S.; Jacobsen, C.; Maser, J.; State Univ. of New York at Stony Brook

    2003-03-01

    The accumulation of trace metals by planktonic protists influences the growth of primary producers, metal biogeochemical cycling, and metal bioaccumulation in aquatic food chains. Despite their importance, unequivocal measurements of trace element concentrations in individual plankton cells have not been possible to date. We have used the 2-ID-E side-branch hard x-ray microprobe at the Advanced Photon Source to measure trace elements in individual marine plankton cells. This microprobe employs zoneplate optics to produce the sub-micron spatial resolution and low background fluorescence required to produce trace element maps of planktonic protist cells ranging in size from 3 to >50 {micro}m. We have developed preservation, rinsing, and mounting protocols that remove most of the salt from our marine samples, thus simplifying the identification of unknown cells and reducing high Cl-related background fluorescence. We have also developed spectral modeling techniques that account for the frequent overlap of adjacent fluorescence peaks and non-uniform detector response. Finally, we have used parallel soft x-ray transmission and epifluorescence microscopy images to estimate C normalized trace element concentrations, identify functional cell types (e.g., photosynthetic vs. non-photosynthetic), and correlate cell structures with spatial patterns in trace element fluorescence.

  4. Real-time gas and particle-phase organic acids measurement at a forest site using chemical ionization high-resolution time-of-flight mass spectrometry during BEACHON-RoMBAS

    Science.gov (United States)

    Yatavelli, L. R.; Stark, H.; Kimmel, J.; Cubison, M.; Day, D. A.; Jayne, J.; Thornton, J. A.; Worsnop, D. R.; Jimenez, J. L.

    2011-12-01

    We present measurement of organic acids in gas and aerosol particles conducted in a ponderosa pine forest during July and August 2011 as part of the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS; http://tinyurl.com/BEACHON-RoMBAS). The measurement technique is based on chemical ionization, high-resolution time-of-flight mass spectrometry and utilizes a Micro-Orifice Volatilization Impactor [MOVI-CI-HR-ToFMS; Yatavelli et al., AS&T, 2010] to collect sub-micron aerosol particles while simultaneously measuring the gas-phase composition. The collected particles are subsequently analyzed by temperature-programmed thermal desorption. The reagent ion chosen for this campaign is the acetate anion (CH3C(O)O-, m/z 59), which reacts selectively via proton transfer with compounds that are stronger gas-phase acids than acetic acid [Veres et al., IJMS, 2008]. Preliminary results show substantial particle-phase concentrations of biogenic oxidation products such as hydroxy-glutaric acid, pinic acid, pinonic acid, and hydroxy-pinonic acid along with numerous lower and higher molecular weight organic acids. Correlations of the organic acid concentrations with meteorological, gas and aerosol parameters measured by other instrumentation are investigated in order to understand the formation, transformation, and partitioning of gas and particle-phase organic acids in a forested environment dominated by terpenes.

  5. Particle cosmology

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.

  6. Particle Physics

    CERN Document Server

    Martin, B R

    2008-01-01

    An essential introduction to particle physics, with coverage ranging from the basics through to the very latest developments, in an accessible and carefully structured text. Particle Physics: Third Edition is a revision of a highly regarded introduction to particle physics. In its two previous editions this book has proved to be an accessible and balanced introduction to modern particle physics, suitable for those students needed a more comprehensive introduction to the subject than provided by the 'compendium' style physics books. In the Third Edition the standard mod

  7. Enhanced computational performance of the lattice Boltzmann model for simulating micron- and submicron-size particle flows and non-Newtonian fluid flows

    Science.gov (United States)

    Başağaoğlu, Hakan; Harwell, John R.; Nguyen, Hoa; Succi, Sauro

    2017-04-01

    Significant improvements in the computational performance of the lattice-Boltzmann (LB) model, coded in FORTRAN90, were achieved through application of enhancement techniques. Applied techniques include optimization of array memory layouts, data structure simplification, random number generation outside the simulation thread(s), code parallelization via OpenMP, and intra- and inter-timestep task pipelining. Effectiveness of these optimization techniques was measured on three benchmark problems: (i) transient flow of multiple particles in a Newtonian fluid in a heterogeneous fractured porous domain, (ii) thermal fluctuation of the fluid at the sub-micron scale and the resultant Brownian motion of a particle, and (iii) non-Newtonian fluid flow in a smooth-walled channel. Application of the aforementioned optimization techniques resulted in an average 21 × performance improvement, which could significantly enhance practical uses of the LB models in diverse applications, focusing on the fate and transport of nano-size or micron-size particles in non-Newtonian fluids.

  8. Morphology changes in human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM₁.₀) and pollen allergens.

    Science.gov (United States)

    Esposito, V; Lucariello, A; Savarese, L; Cinelli, M P; Ferraraccio, F; Bianco, A; De Luca, A; Mazzarella, G

    2012-12-01

    In the recent literature there has been an increased interest in the effects of particulate matter on the respiratory tract. The objective of this study was to use an in vitro model of type II lung epithelium (A549) to evaluate the cell ability to take up sub-micron PM(1.0) particles (PM(1.0)), Parietaria officinalis (ALL), and PM(1.0) + ALL together. Morphological analysis performed by Transmission Electron Microscope (TEM) showed that PM and ALL interacted with the cell surface, then penetrating into the cytoplasm. Each single treatment was able to point out a specific change in the morphology. The cells treated appear healthy and not apoptotic. The main effect was the increase of: multilamellar bodies, lysosomal enzymes, microvilli, and presence of vesicle/vacuoles containing particles. These observations demonstrate morphological and functional alterations related to the PM(1.0) and P. officinalis and confirm the induction of the inflammatory response in lung cells exposed to the inhalable particles. Copyright © 2012. Published by Elsevier Ltd.

  9. Noble Metal/Ceramic Composites in Flame Processes

    DEFF Research Database (Denmark)

    Schultz, Heiko; Madler, Lutz; Strobel, Reto

    size is mainly dependent on its loading [3,7]. In this study, the role of the supporting metal oxide on the noble metal particle size was systematically investigated for the flame spray pyrolysis process. The materials were produced at fixed process conditions such as resident time of the particles...... in the flame, energy input, maximum temperature and cooling rate. Having the same surface area of the support and metal loading, the materials exhibited different noble metal particle sizes. A fundamental understanding of the mechanisms of metal particle formation in the flame and the effect of the metal oxide...

  10. Particle physics

    CERN Document Server

    Carlsmith, Duncan

    2012-01-01

    Particle Physics is the first book to connect theory and experiment in particle physics. Duncan Carlsmith provides the first accessible exposition of the standard model with sufficient mathematical depth to demystify the language of gauge theory and Feynman diagrams used by researchers in the field. Carlsmith also connects theories to past, present, and future experiments.

  11. Imaging flow cytometry assays for quantifying pigment grade titanium dioxide particle internalization and interactions with immune cells in whole blood.

    Science.gov (United States)

    Hewitt, Rachel E; Vis, Bradley; Pele, Laetitia C; Faria, Nuno; Powell, Jonathan J

    2017-10-01

    Pigment grade titanium dioxide is composed of sub-micron sized particles, including a nanofraction, and is widely utilized in food, cosmetic, pharmaceutical, and biomedical industries. Oral exposure to pigment grade titanium dioxide results in at least some material entering the circulation in humans, although subsequent interactions with blood immune cells are unknown. Pigment grade titanium dioxide is employed for its strong light scattering properties, and this work exploited that attribute to determine whether single cell-particle associations could be determined in immune cells of human whole blood at "real life" concentrations. In vitro assays, initially using isolated peripheral blood mononuclear cells, identified titanium dioxide associated with the surface of, and within, immune cells by darkfield reflectance in imaging flow cytometry. This was confirmed at the population level by side scatter measurements using conventional flow cytometry. Next, it was demonstrated that imaging flow cytometry could quantify titanium dioxide particle-bearing cells, within the immune cell populations of fresh whole blood, down to titanium dioxide levels of 10 parts per billion, which is in the range anticipated for human blood following titanium dioxide ingestion. Moreover, surface association and internal localization of titanium dioxide particles could be discriminated in the assays. Overall, results showed that in addition to the anticipated activity of blood monocytes internalizing titanium dioxide particles, neutrophil internalization and cell membrane adhesion also occurred, the latter for both phagocytic and nonphagocytic cell types. What happens in vivo and whether this contributes to activation of one or more of these different cells types in blood merits further attention. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  12. Metal-metal-hofteproteser

    DEFF Research Database (Denmark)

    Ulrich, Michael; Overgaard, Søren; Penny, Jeannette

    2014-01-01

    In Denmark 4,456 metal-on-metal (MoM) hip prostheses have been implanted. Evidence demonstrates that some patients develope adverse biological reactions causing failures of MoM hip arthroplasty. Some reactions might be systemic. Failure rates are associated with the type and the design of the Mo...

  13. Metallated metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

    2017-08-22

    Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

  14. Metallated metal-organic frameworks

    Science.gov (United States)

    Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

    2017-02-07

    Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

  15. Morphology of colloidal metal pyrophosphate salts

    NARCIS (Netherlands)

    van Leeuwen, Y.M.; Velikov, K.; Kegel, W.K.

    2012-01-01

    We report the preparation and characterization of colloidal particles of several pyrophosphate metal salts, including, for the first time, salts containing multiple metals. These materials are compared in order to determine the influence of the composition and experimental conditions on particle

  16. Elementary particles

    Science.gov (United States)

    Fritzsch, Harald; Heusch, Karin

    Introduction -- Electrons and atomic nuclei -- Quantum properties of atoms and particles -- The knives of Democritus -- Quarks inside atomic nuclei -- Quantum electrodynamics -- Quantum chromodynamics -- Mesons, baryons, and quarks -- Electroweak interactions -- Grand unification -- Conclusion.

  17. Aprovechamiento de partículas de ultrafinos de carbón de una planta lavadora en la producción de coque metalúrgico Using ultrafine particles from a coal washing plant in metallurgical coke production

    Directory of Open Access Journals (Sweden)

    Díaz Velásquez José de Jesús

    2011-05-01

    Full Text Available

    Se estudió el aprovechamiento en mezclas de ultrafinos provenientes de una planta de lavado de carbón para la producción de coque por el proceso de briquetación, utilizando 6% en peso de alquitrán de carbón como aglomerante. Se caracterizaron las materias primas y se realizó una prueba piloto de coquización en un horno tipo Koppers. Se determinó la calidad del coque por pruebas de análisis próximo, estabilidad (Micum 10, M10 y Micum 40, M40, índice de reactividad del coque al CO2 (CRI y de resistencia después de la reacción con dióxido de carbono (CSR. Los resultados mostraron que la briquetación permite obtener un coque con un CRI de 19,0% y un CSR de 75,6%, características requeridas en los procesos metalúrgicos.

    Blending ultrafine particles from a coal washing plant was studied for coke production by briquetting usi