Electrostatic charge characteristics of jet nebulized aerosols.

Science.gov (United States)

Kwok, Philip Chi Lip; Trietsch, Sebastiaan J; Kumon, Michiko; Chan, Hak-Kim

2010-06-01

Liquid droplets can be spontaneously charged in the absence of applied electric fields by spraying. It has been shown by computational simulation that charges may influence particle deposition in the airways. The electrostatic properties of jet nebulized aerosols and their potential effects on lung deposition have hardly been studied. A modified electrical low pressure impactor (ELPI) was employed to characterize the aerosol charges generated from jet nebulized commercial products. The charge and size measurements were conducted at 50% RH and 22 degrees C with a modified ELPI. Ventolin, Bricanyl, and Atrovent were nebulized using PARI LC Plus jet nebulizers coupled to a DeVilbiss Pulmo-Aide compressor. The aerosols were sampled in 30-sec durations. The drug deposits on the impactor stages were assayed chemically using high-performance liquid chromatography (HPLC). The charges of nebulized deionized water, isotonic saline, and the three commercial products diluted with saline were also measured to analyze the contributions of the major nebule ingredients on charging. No mass assays were performed on these runs. All three commercial nebules generated net negative charges. The magnitude of the charges reduced over the period of nebulization. Ventolin and Bricanyl yielded similar charge profiles. Highly variable charges were produced from deionized water. On the other hand, nebulized saline reproducibly generated net positive charges. Diluted commercial nebules showed charge polarity inversion. The charge profiles of diluted salbutamol and terbutaline solutions resembled those of saline, while the charges from diluted ipratropium solutions fluctuated near neutrality. The charge profiles were shown to be influenced by the concentration and physicochemical properties of the drugs, as well as the history of nebulization. The drugs may have unique isoelectric concentrations in saline at which the nebulized droplets would carry near-zero charges. According to results from

Design of a device for simultaneous particle size and electrostatic charge measurement of inhalation drugs.

Science.gov (United States)

Zhu, Kewu; Ng, Wai Kiong; Shen, Shoucang; Tan, Reginald B H; Heng, Paul W S

2008-11-01

To develop a device for simultaneous measurement of particle aerodynamic diameter and electrostatic charge of inhalation aerosols. An integrated system consisting of an add-on charge measurement device and a liquid impinger was developed to simultaneously determine particle aerodynamic diameter and electrostatic charge. The accuracy in charge measurement and fine particle fraction characterization of the new system was evaluated. The integrated system was then applied to analyze the electrostatic charges of a DPI formulation composed of salbutamol sulphate-Inhalac 230 dispersed using a Rotahaler. The charge measurement accuracy was comparable with the Faraday cage method, and incorporation of the charge measurement module had no effect on the performance of the liquid impinger. Salbutamol sulphate carried negative charges while the net charge of Inhalac 230 and un-dispersed salbutamol sulphate was found to be positive after being aerosolized from the inhaler. The instantaneous current signal was strong with small noise to signal ratio, and good reproducibility of charge to mass ratio was obtained for the DPI system investigated. A system for simultaneously measuring particle aerodynamic diameter and aerosol electrostatic charges has been developed, and the system provides a non-intrusive and reliable electrostatic charge characterization method for inhalation dosage forms.

Unipolar charging of nanoparticles by the Surface-discharge Microplasma Aerosol Charger (SMAC)

International Nuclear Information System (INIS)

Kwon, Soon-Bark; Sakurai, Hiromu; Seto, Takafumi

2007-01-01

In this paper, we report the development of a novel unipolar charger for nanoparticles, a system that achieves low particle loss and high charging efficiency without the use of sheath air. The efficient unipolar charging of the system is realized mainly by the surface-discharge microplasma unit, a device previously applied with good success to the neutralization or charging of submicron particles [Kwon et al., 2005, Aerosol Sci. Technol., 39, 987-1001; 2006, J. Aerosol Sci., 37, 483-499]. The unipolar charger generates unipolar ions using the surface discharge of a single electrode with a DC pulse supply. This marks an advance from our previous method of generating bipolar ions with the use of dual electrodes in earlier studies. We evaluated the efficiency of the penetration (or loss) and charging of nanoparticles in the size range of 3-15 nm, then compared the charging efficiencies measured with those predicted by diffusion charging theory. More than 90% of inlet nanoparticles penetrated the charger (less than 10% of the particle were lost) without the use of sheath air. Other chargers have only realized this high penetration efficiency by relying on sheath air flow. Moreover, the measured charging efficiencies agreed well with those predicted by diffusion charging theory and were somewhat higher and more size-dependent than the charging efficiencies of other nanoparticle chargers

Using measurements of the aerosol charging state in determination of the particle growth rate and the proportion of ion-induced nucleation

Directory of Open Access Journals (Sweden)

J. Leppä

2013-01-01

Full Text Available The fraction of charged nucleation mode particles as a function of particle diameter depends on the particle growth rate and the proportion of particles formed via ion-induced nucleation. In this study we have tested the applicability of recent data analysis methods to determine the growth rate and the proportion of ion-induced nucleation from the measured charged fractions. For this purpose we have conducted a series of aerosol dynamic simulations covering a wide range of atmospheric conditions. The growth rate and initial fraction of charged particles were estimated from simulated data using these methods and compared with the values obtained directly from the simulations. We found that the data analysis methods used in this study should not be used when the nuclei growth rate is less than ~3 nm h⁻¹, or when charged particles grow much more rapidly than neutral ones. Furthermore, we found that the difference in removal rates of neutral and charged particles should be taken into account when estimating the proportion of ion-induced nucleation. Neglecting the higher removal rate of charged particles compared with that of neutral ones could result in an underestimation of the proportion of ion-induced nucleation by up to a factor of 2. This underestimation is further increased if charged particles grow more rapidly than neutral ones. We also provided a simple way of assessing whether these methods are suitable for analyzing data measured under specific conditions. The assessment procedure was illustrated using a few examples of actual measurement sites with a more detailed examination of the typical conditions observed at the SMEAR II station in Hyytiälä, Finland.

Improved non-invasive method for aerosol particle charge measurement employing in-line digital holography

Science.gov (United States)

Tripathi, Anjan Kumar

Electrically charged particles are found in a wide range of applications ranging from electrostatic powder coating, mineral processing, and powder handling to rain-producing cloud formation in atmospheric turbulent flows. In turbulent flows, particle dynamics is influenced by the electric force due to particle charge generation. Quantifying particle charges in such systems will help in better predicting and controlling particle clustering, relative motion, collision, and growth. However, there is a lack of noninvasive techniques to measure particle charges. Recently, a non-invasive method for particle charge measurement using in-line Digital Holographic Particle Tracking Velocimetry (DHPTV) technique was developed in our lab, where charged particles to be measured were introduced to a uniform electric field, and their movement towards the oppositely charged electrode was deemed proportional to the amount of charge on the particles (Fan Yang, 2014 [1]). However, inherent speckle noise associated with reconstructed images was not adequately removed and therefore particle tracking data was contaminated. Furthermore, particle charge calculation based on particle deflection velocity neglected the particle drag force and rebound effect of the highly charged particles from the electrodes. We improved upon the existing particle charge measurement method by: 1) hologram post processing, 2) taking drag force into account in charge calculation, 3) considering rebound effect. The improved method was first fine-tuned through a calibration experiment. The complete method was then applied to two different experiments, namely conduction charging and enclosed fan-driven turbulence chamber, to measure particle charges. In all three experiments conducted, the particle charge was found to obey non-central t-location scale family of distribution. It was also noted that the charge distribution was insensitive to the change in voltage applied between the electrodes. The range of voltage

Algorithm of Data Reduce in Determination of Aerosol Particle Size Distribution at Damps/C

International Nuclear Information System (INIS)

Muhammad-Priyatna; Otto-Pribadi-Ruslanto

2001-01-01

The analysis had to do for algorithm of data reduction on Damps/C (Differential Mobility Particle Sizer with Condensation Particle Counter) system, this is for determine aerosol particle size distribution with range 0,01 μm to 1 μm in diameter. Damps/C (Differential Mobility Particle Sizer with Condensation Particle Counter) system contents are software and hardware. The hardware used determine of mobilities of aerosol particle and so the software used determine aerosol particle size distribution in diameter. The mobilities and diameter particle had connection in the electricity field. That is basic program for reduction of data and particle size conversion from particle mobility become particle diameter. The analysis to get transfer function value, Ω, is 0.5. The data reduction program to do conversation mobility basis become diameter basis with number efficiency correction, transfer function value, and poly charge particle. (author)

Topics in current aerosol research

CERN Document Server

Hidy, G M

1971-01-01

Topics in Current Aerosol Research deals with the fundamental aspects of aerosol science, with emphasis on experiment and theory describing highly dispersed aerosols (HDAs) as well as the dynamics of charged suspensions. Topics covered range from the basic properties of HDAs to their formation and methods of generation; sources of electric charges; interactions between fluid and aerosol particles; and one-dimensional motion of charged cloud of particles. This volume is comprised of 13 chapters and begins with an introduction to the basic properties of HDAs, followed by a discussion on the form

Measurement of triboelectric charging of moving micro particles by means of an inductive cylindrical probe

International Nuclear Information System (INIS)

Nesterov, A; Loeffler, F; Koenig, K; Trunk, U; Leibe, K; Felgenhauer, T; Bischoff, F R; Breitling, F; Lindenstruth, V; Stadler, V; Hausmann, M

2007-01-01

We present a method based on induced currents in a cylindrical probe which allows analysis of the micro-particle charging processes in an aerosol. The micro particles were triboelectrically charged by passing through a dielectric tube coaxially mounted into the probe. The cylindrical probe enabled the quantification of particle charging without prior calibration of the probe. An analytic model was developed for the description of the measured induced currents and implemented into a computer simulation program. The combination of model simulations and an appropriate experimental setup revealed comprehensive data for the determination of the particles' electric charge against time of flight through the tube. In methodological proof of principle experiments, the formations of particle clouds with charges of different signs were observed using magnetite micro particles

The Impact of Aerosol Particle Mixing State on the Hygroscopicity of Sea Spray Aerosol.

Science.gov (United States)

Schill, Steven R; Collins, Douglas B; Lee, Christopher; Morris, Holly S; Novak, Gordon A; Prather, Kimberly A; Quinn, Patricia K; Sultana, Camille M; Tivanski, Alexei V; Zimmermann, Kathryn; Cappa, Christopher D; Bertram, Timothy H

2015-06-24

Aerosol particles influence global climate by determining cloud droplet number concentrations, brightness, and lifetime. Primary aerosol particles, such as those produced from breaking waves in the ocean, display large particle-particle variability in chemical composition, morphology, and physical phase state, all of which affect the ability of individual particles to accommodate water and grow into cloud droplets. Despite such diversity in molecular composition, there is a paucity of methods available to assess how particle-particle variability in chemistry translates to corresponding differences in aerosol hygroscopicity. Here, an approach has been developed that allows for characterization of the distribution of aerosol hygroscopicity within a chemically complex population of atmospheric particles. This methodology, when applied to the interpretation of nascent sea spray aerosol, provides a quantitative framework for connecting results obtained using molecular mimics generated in the laboratory with chemically complex ambient aerosol. We show that nascent sea spray aerosol, generated in situ in the Atlantic Ocean, displays a broad distribution of particle hygroscopicities, indicative of a correspondingly broad distribution of particle chemical compositions. Molecular mimics of sea spray aerosol organic material were used in the laboratory to assess the volume fractions and molecular functionality required to suppress sea spray aerosol hygroscopicity to the extent indicated by field observations. We show that proper accounting for the distribution and diversity in particle hygroscopicity and composition are important to the assessment of particle impacts on clouds and global climate.

PIXE analysis of atmospheric aerosol and hydrometeor particles

International Nuclear Information System (INIS)

Groeneveld, K.O.; Hofmann, D.; Georgii, H.W.

1993-01-01

Atmospheric aerosol and hydrometeor particles act decisively on our weather, climate and thereby on all living conditions on Earth. Particle induced X-ray emission (PIXE) analysis has been demonstrated to be an extremely valuable tool for quantitative and qualitative elemental analysis of aerosol particles and hydrometeors. Reliability and detection limits of PIXE are determined, including comparison with other techniques. Aerosol particles are collected on a global scale in ground stations, or by ships and by planes. Correlation between wind direction and elemental composition of atmospheric aerosols, elemental particle size distributions of the tropospheric aerosol, aerosol elemental composition in particle size fractions in the case of long range transport, transport pathways of pollution aerosol, and trace element content precipitation are discussed. Hydrometeors were studied in the form of rain, snow, fog, dew and frost. The time dependence of the melting process of snow was studied in detail, in particular the washout phenomena of impurity ions. (orig.)

Workplace aerosol mass concentration measurement using optical particle counters.

Science.gov (United States)

Görner, Peter; Simon, Xavier; Bémer, Denis; Lidén, Göran

2012-02-01

Direct-reading aerosol measurement usually uses the optical properties of airborne particles to detect and measure particle concentration. In the case of occupational hygiene, mass concentration measurement is often required. Two aerosol monitoring methods are based on the principle of light scattering: optical particle counting (OPC) and photometry. The former analyses the light scattered by a single particle, the latter by a cloud of particles. Both methods need calibration to transform the quantity of scattered light detected into particle concentration. Photometers are simpler to use and can be directly calibrated to measure mass concentration. However, their response varies not only with aerosol concentration but also with particle size distribution, which frequently contributes to biased measurement. Optical particle counters directly measure the particle number concentration and particle size that allows assessment of the particle mass provided the particles are spherical and of known density. An integrating algorithm is used to calculate the mass concentration of any conventional health-related aerosol fraction. The concentrations calculated thus have been compared with simultaneous measurements by conventional gravimetric sampling to check the possibility of field OPC calibration with real workplace aerosols with a view to further monitoring particle mass concentration. Aerosol concentrations were measured in the food industry using the OPC GRIMM® 1.108 and the CIP 10-Inhalable and CIP 10-Respirable (ARELCO®) aerosol samplers while meat sausages were being brushed and coated with calcium carbonate. Previously, the original OPC inlet had been adapted to sample inhalable aerosol. A mixed aerosol of calcium carbonate and fungi spores was present in the workplace. The OPC particle-size distribution and an estimated average particle density of both aerosol components were used to calculate the mass concentration. The inhalable and respirable aerosol fractions

Measurement of the electrostatic charge in airborne particles: I - development of the equipment and preliminary results

Directory of Open Access Journals (Sweden)

Marra Jr. W.D.

2000-01-01

Full Text Available The design and construction of a equipment capable of measuring the electrostatic charges in aerosols, named the electrostatic charge classifier, were carried out. They were based on the concept of particle electromobility and the charge classifier was intended to classify the nature and the distribution of electrostatic charges as a function of particle size. The resulting piece of equipment is easy to dismount, which facilitates its cleaning and transport, and easy to operate. Early results indicate that the values of electrostatic charge measured on test particles are inside the range reported in the literature, indicating the adequacy of the technique utilized.

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

Directory of Open Access Journals (Sweden)

L. Laakso

2007-01-01

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

Penetration of Combustion Aerosol Particles Through Filters of NIOSH-Certified Filtering Facepiece Respirators (FFRs).

Science.gov (United States)

Gao, Shuang; Kim, Jinyong; Yermakov, Michael; Elmashae, Yousef; He, Xinjian; Reponen, Tiina; Grinshpun, Sergey A

2015-01-01

Filtering facepiece respirators (FFRs) are commonly worn by first responders, first receivers, and other exposed groups to protect against exposure to airborne particles, including those originated by combustion. Most of these FFRs are NIOSH-certified (e.g., N95-type) based on the performance testing of their filters against charge-equilibrated aerosol challenges, e.g., NaCl. However, it has not been examined if the filtration data obtained with the NaCl-challenged FFR filters adequately represent the protection against real aerosol hazards such as combustion particles. A filter sample of N95 FFR mounted on a specially designed holder was challenged with NaCl particles and three combustion aerosols generated in a test chamber by burning wood, paper, and plastic. The concentrations upstream (Cup) and downstream (Cdown) of the filter were measured with a TSI P-Trak condensation particle counter and a Grimm Nanocheck particle spectrometer. Penetration was determined as (Cdown/Cup) ×100%. Four test conditions were chosen to represent inhalation flows of 15, 30, 55, and 85 L/min. Results showed that the penetration values of combustion particles were significantly higher than those of the "model" NaCl particles (p combustion particles. Aerosol type, inhalation flow rate and particle size were significant (p combustion particles through R95 and P95 FFR filters (were tested in addition to N95) were not significantly higher than that obtained with NaCl particles. The findings were attributed to several effects, including the degradation of an N95 filter due to hydrophobic organic components generated into the air by combustion. Their interaction with fibers is anticipated to be similar to those involving "oily" particles. The findings of this study suggest that the efficiency of N95 respirator filters obtained with the NaCl aerosol challenge may not accurately predict (and rather overestimate) the filter efficiency against combustion particles.

A hybrid charged-particle guide for studying (n, charged particle) reactions

International Nuclear Information System (INIS)

Haight, R.C.; White, R.M.; Zinkle, S.J.

1983-01-01

Charged-particle transport systems consisting of magnetic quadrupole lenses have been employed in recent years in the study of (n, charged particle) reactions. A new transport system was completed at the laboratory that is based both on magnetic lenses as well as electrostatic fields. The magnetic focusing of the charged-particle guide is provided by six magnetic quadrupole lenses arranged in a CDCCDC sequence (in the vertical plane). The electrostatic field is produced by a wire at high voltage which stretches the length of the guide and is physically at the centre of the magnetic axis. The magnetic lenses are used for charged particles above 5 MeV; the electrostatic guide is used for lower energies. This hybrid system possesses the excellent focusing and background rejection properties of other magnetic systems. For low energy charged-particles, the electrostatic transport avoids the narrow band-passes in charged-particle energy which are a problem with purely magnetic transport systems. This system is installed at the LLNL Cyclograaff facility for the study of (n, charged particle) reactions at neutron energies up to 35 MeV. (Auth.)

The hygroscopicity of indoor aerosol particles

International Nuclear Information System (INIS)

Wei, L.

1993-07-01

A system to study the hygroscopic growth of particle was developed by combining a Tandem Differential Mobility Analyzer (TDMA) with a wetted wall reactor. This system is capable of mimicking the conditions in human respiratory tract, and measuring the particle size change due to the hygroscopic growth. The performance of the system was tested with three kinds of particles of known composition, NaCl, (NH 4 ) 2 SO 4 , and (NH 4 )HS0 4 particles. The hygroscopicity of a variety of common indoor aerosol particles was studied including combustion aerosols (cigarette smoking, cooking, incenses and candles) and consumer spray products such as glass cleaner, general purpose cleaner, hair spray, furniture polish spray, disinfectant, and insect killer. Experiments indicate that most of the indoor aerosols show some hygroscopic growth and only a few materials do not. The magnitude of hygroscopic growth ranges from 20% to 300% depending on the particle size and fraction of water soluble components

Variation in penetration of submicrometric particles through electrostatic filtering facepieces during exposure to paraffin oil aerosol.

Science.gov (United States)

Plebani, Carmela; Listrani, Stefano; Tranfo, Giovanna; Tombolini, Francesca

2012-01-01

Several studies show the increase of penetration through electrostatic filters during exposure to an aerosol flow, because of particle deposition on filter fibers. We studied the effect of increasing loads of paraffin oil aerosol on the penetration of selected particle sizes through an electrostatic filtering facepiece. FFP2 facepieces were exposed for 8 hr to a flow rate of 95.0 ± 0.5 L/min of polydisperse paraffin aerosol at 20.0 ± 0.5 mg/m(3). The penetration of bis(2-ethylhexyl)sebacate (DEHS) monodisperse neutralized aerosols, with selected particle size in the 0.03-0.40 μm range, was measured immediately prior to the start of the paraffin aerosol loading and at 1, 4, and 8 hr after the start of paraffin aerosol loading. Penetration through isopropanol-treated facepieces not oil paraffin loaded was also measured to evaluate facepiece behavior when electrostatic capture mechanisms are practically absent. During exposure to paraffin aerosol, DEHS penetration gradually increased for all aerosol sizes, and the most penetrating particle size (0.05 μm at the beginning of exposure) shifted slightly to larger diameters. After the isopropanol treatment, the higher penetration value was 0.30 μm. In addition to an increased penetration during paraffin loading at a given particle size, the relative degree of increase was greater as the particle size increased. Penetration value measured after 8 hr for 0.03-μm particles was on average 1.6 times the initial value, whereas it was about 8 times for 0.40-μm particles. This behavior, as well evidenced in the measurements of isopropanol-treated facepieces, can be attributed to the increasing action in particle capture of the electrostatic forces (Coulomb and polarization), which depend strictly on the diameter and electrical charge of neutralized aerosol particles. With reference to electrostatic filtering facepieces as personal protective equipment, results suggest the importance of complying with the manufacturer

Charged particle detector

International Nuclear Information System (INIS)

Hagen, R.D.

1975-01-01

A device for detecting the emission of charged particles from a specimen is described. The specimen is placed within an accumulator means which statically accumulates any charged particles emitted from the specimen. The accumulator means is pivotally positioned between a first capacitor plate having a positive electrical charge and a second capacitor plate having a negative electrical charge. The accumulator means is attracted to one capacitor plate and repelled from the other capacitor plate by an amount proportional to the amount and intensity of charged particles emitted by the specimen. (auth)

Formation and dynamic change of aerosol particles

International Nuclear Information System (INIS)

Kasahara, Mikio

1986-01-01

Processes of aerosol particle nucleation are roughly grouped into two types. In one, aerosol is produced as a result of dispersion of solid or liquid by mechanical force while in the other it is formed through phase transition from gas to solid or liquid due to cohesion caused by cooling, expansion or chemical reaction. This article reviews various aspects of aerosol particle nucleation through the latter type of processes and behaviors of the particles formed. Gas-to-particle conversion processes are divided into those of homogeneous and heterogeneous nucleation, and the former include homogeneous homomolecular and homogeneous heteromolecular nucleation processes. Here, homoneneous homomolecular nucleation is described centering on the theories proposed by Backer and Doring-Zeldovich-Volmer-Frenkel while homogeneous heteromolecular systems are outlined citing the theory developed by Kiang and Stauffer. Heterogeneous nucleation (or heterogeneous condensation) is discussed on the basis of the relationship between the mean free path of air molecules and the particle size. Various theories for particle formation and growth are listed and briefly outlined. Some of them are compared with experimental results. Models are cited to explain behaviors of aerosol particles after being formed. Also described is simulation of particle nucleation and growth in relation to atmospheric pollution and possible accidents of liquid-metal fast breeder reactors. (Nogami, K.)

Labeling suspended aerosol particles with short-lived radionuclides for determination of particle deposition

International Nuclear Information System (INIS)

Smith, M.F.; Bryant, S.; Welch, S.; Digenis, G.A.

1984-01-01

Radiotracer techniques were developed to examine parameters that characterize pressurized aerosols designed to deliver insoluble particles suspended in the aerosol formulation. Microaggregated bovine serum albumin microspheres that were to be suspended were labeled with iodine-131 (t1/2 . 8 d). This iodination procedure (greater than 80% effective) is also applicable to iodine-123, which possesses superior characteristics for external imaging and further in vivo studies. This report shows that for pressurized aerosols containing suspended particles, each metered dose is approximately equal (not including the priming doses and the emptying doses). Increase in the delivery of the albumin particles out of the canister was best achieved by pretreating the valve assembly with a solution of 2% (w/v) bovine serum albumin in phosphate buffer. Use of a cascade impactor delineated the particle size distribution of the micropheres, with the majority of particles ranging in size from 2 to 8 microns. The data disclosed here indicate that the techniques developed with short-lived radionuclides can be used to quantitate each metered dose, characterize the particle size distribution profile of the aerosol contents, and determine the extent of deposition of the particles in the aerosol canister and all of its components

Aerosol charging state at an urban site: new analytical approach and implications for ion-induced nucleation

Directory of Open Access Journals (Sweden)

S. Gagné

2012-05-01

Full Text Available The charging state of aerosol populations was determined using an Ion-DMPS in Helsinki, Finland between December 2008 and February 2010. We extrapolated the charging state and calculated the ion-induced nucleation fraction to be around 1.3 % ± 0.4 % at 2 nm and 1.3 % ± 0.5 % at 1.5 nm, on average. We present a new method to retrieve the average charging state for a new particle formation event, at a given size and polarity. We improve the uncertainty assessment and fitting technique used previously with an Ion-DMPS. We also use a new theoretical framework that allows for different concentrations of small ions for different polarities (polarity asymmetry. We extrapolate the ion-induced fraction using polarity symmetry and asymmetry. Finally, a method to calculate the growth rates from the behaviour of the charging state as a function of the particle diameter using polarity symmetry and asymmetry is presented and used on a selection of new particle formation events.

Continuous air monitor for alpha-emitting aerosol particles

International Nuclear Information System (INIS)

McFarland, A.R.; Ortiz, C.A.; Rodgers, J.C.; Nelson, D.C.

1991-01-01

A new alpha continuous air monitor (CAM) sampler is being developed for use in detecting the presence of alpha-emitting aerosol particles. The effort involves design, fabrication and evaluation of systems for the collection of aerosol and for the processing of data to speciate and quantify the alpha emitters of the interest. At the present time the authors have a prototype of the aerosol sampling system and they have performed wind tunnel tests to characterize the performance of the device for different particle sizes, wind speeds, flow rates and internal design parameters. The results presented herein deal with the aerosol sampling aspects of the new CAM sampler. Wind tunnel tests show that ≥ 50% of 10 μm aerodynamic equivalent diameter (AED) particles penetrate the flow system from the ambient air to the collection filter when the flow rate is 57 L/min (2 cfm) and the wind speed is 1 m/s. The coefficient of variation of deposits of 10 μm AED aerosol particles on the collection filter is 7%. An inlet fractionator for removing high mobility background aerosol particles has been designed and successfully tested. The results show that it is possible to strip 95% of freshly formed radon daughters and 33% of partially aged radon daughters from the aerosol sample. This approach offers the opportunity to improve the signal-to-noise ratio in the alpha energy spectrum region of interest thereby enhancing the performance of background compensation algorithms

Measuring momentum for charged particle tomography

Science.gov (United States)

Morris, Christopher; Fraser, Andrew Mcleod; Schultz, Larry Joe; Borozdin, Konstantin N.; Klimenko, Alexei Vasilievich; Sossong, Michael James; Blanpied, Gary

2010-11-23

Methods, apparatus and systems for detecting charged particles and obtaining tomography of a volume by measuring charged particles including measuring the momentum of a charged particle passing through a charged particle detector. Sets of position sensitive detectors measure scattering of the charged particle. The position sensitive detectors having sufficient mass to cause the charged particle passing through the position sensitive detectors to scatter in the position sensitive detectors. A controller can be adapted and arranged to receive scattering measurements of the charged particle from the charged particle detector, determine at least one trajectory of the charged particle from the measured scattering; and determine at least one momentum measurement of the charged particle from the at least one trajectory. The charged particle can be a cosmic ray-produced charged particle, such as a cosmic ray-produced muon. The position sensitive detectors can be drift cells, such as gas-filled drift tubes.

Aerosol microphysics of indoor radon

International Nuclear Information System (INIS)

1989-01-01

To provide an improved description for the deposition of charge on ultrafine aerosol particles, we have introduced for the first time into aerosol studies the ''jellium'' model potential to quantitatively describe the interaction energy at long range between a conducting particle and an ion (here modeled as a point charge). The benefit of utilizing this potential, in its linearized approximation, is that it accounts for the response of the particle's conduction electrons to the field of the ion rather than relying upon a macroscopic picture whose validity is nuclear for sufficiently small particles. In the limit of large separations or of larger particles, the jellium and image potentials converge rapidly implying that no inconsistency exists between the generally-accepted approach for larger particles and our contribution. As a part of our work, we have given an accurate fit to the experimental data in the literature on the charging rate of neutral particles in the 4--50 nm range of radii without the need for assumptions other than of the charging ion properties. The results of this work will contribute to the ability to model charged radon daughter cluster ion attachment to high-diffusivity particles and conversely to the ability to model charge attachment on high-diffusivity uncharged particles containing a radon daughter

Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

Energy Technology Data Exchange (ETDEWEB)

Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

2015-10-20

Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

Microphysical processing of aerosol particles in orographic clouds

Science.gov (United States)

Pousse-Nottelmann, S.; Zubler, E. M.; Lohmann, U.

2015-08-01

An explicit and detailed treatment of cloud-borne particles allowing for the consideration of aerosol cycling in clouds has been implemented into COSMO-Model, the regional weather forecast and climate model of the Consortium for Small-scale Modeling (COSMO). The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed us to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener-Bergeron-Findeisen (WBF) process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snowflakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snowflakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. Thereby, the processes impact the total aerosol number and mass and additionally alter the shape of the aerosol size distributions by enhancing the internally mixed/soluble Aitken and accumulation mode and generating coarse-mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases

Filter-based Aerosol Measurement Experiments using Spherical Aerosol Particles under High Temperature and High Pressure

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Chan; Jung, Woo Young; Lee, Hyun Chul; Lee, Doo Young [FNC TECH., Yongin (Korea, Republic of)

2016-05-15

Optical Particle Counter (OPC) is used to provide real-time measurement of aerosol concentration and size distribution. Glass fiber membrane filter also be used to measure average mass concentration. Three tests (MTA-1, 2 and 3) have been conducted to study thermal-hydraulic effect, a filtering tendency at given SiO{sub 2} particles. Based on the experimental results, the experiment will be carried out further with a main carrier gas of steam and different aerosol size. The test results will provide representative behavior of the aerosols under various conditions. The aim of the tests, MTA 1, 2 and 3, are to be able to 1) establish the test manuals for aerosol generation, mixing, sampling and measurement system, which defines aerosol preparation, calibration, operating and evaluation method under high pressure and high temperature 2) develop commercial aerosol test modules applicable to the thermal power plant, environmental industry, automobile exhaust gas, chemical plant, HVAC system including nuclear power plant. Based on the test results, sampled aerosol particles in the filter indicate that important parameters affecting aerosol behavior aerosols are 1) system temperature to keep above a evaporation temperature of ethanol and 2) aerosol losses due to the settling by ethanol liquid droplet.

Single particle composition measurements of artificial Calcium Carbonate aerosols

Science.gov (United States)

Zorn, S. R.; Mentel, T. F.; Schwinger, T.; Croteau, P. L.; Jayne, J.; Worsnop, D. R.; Trimborn, A.

2012-12-01

Mineral dust, with an estimated total source from natural and anthropogenic emissions of up to 2800 Tg/yr, is one of the two largest contributors to total aerosol mass, with only Sea salt having a similar source strength (up to 2600 Tg/yr). The composition of dust particles varies strongly depending on the production process and, most importantly, the source location. Therefore, the composition of single dust particles can be used both to trace source regions of air masses as well as to identify chemical aging processes. Here we present results of laboratory studies on generating artificial calcium carbonate (CaCO3) particles, a model compound for carbonaceous mineral dust particles. Particles were generated by atomizing an aqueous hydrogen carbonate solution. Water was removed using a silica diffusion dryer., then the particles were processed in an oven at temperatures up to 900°C, converting the hydrogen carbonate to its anhydrous form. The resulting aerosol was analyzed using an on-line single particle laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF). The results confirm the conversion to calcium carbonate, and validate that the produced particles indeed can be used as a model compound for carbonaceous dust aerosols.

Nuclear track radiography of 'hot' aerosol particles

International Nuclear Information System (INIS)

Boulyga, S.F.; Kievitskaja, A.I.; Kievets, M.K.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Perelygin, V.P.; Petrova, R.; Brandt, R.; Vater, P.

1999-01-01

Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the α-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (γ,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by 235 U, 239 Pu and 241 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 -6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of 'hot' particles

Electrostatics of Pharmaceutical Aerosols for Pulmonary Delivery.

Science.gov (United States)

Lip Kwok, Philip Chi

2015-01-01

This paper provides a review on key research findings in the rapidly developing area of pharmaceutical aerosol electrostatics. Solids and liquids can become charged without electric fields, the former by contact or friction and the latter by flowing or spraying. Therefore, charged particles and droplets carrying net charges are produced from pharmaceutical inhalers (e.g. dry powder inhalers, metered dose inhalers, and nebulisers) due to the mechanical processes involved in aerosolisation. The charging depends on many physicochemical factors, such as formulation composition, solid state properties, inhaler material and design, and relative humidity. In silico, in vitro, and limited in vivo studies have shown that electrostatic charges may potentially influence particle deposition in the airways. However, the evidence is not yet conclusive. Furthermore, there are currently no regulatory requirements on the characterisation and control of the electrostatic properties of inhaled formulations. Besides the need for further investigations on the relationship between physicochemical factors and charging characteristics of the aerosols, controlled and detailed in vivo studies are also required to confirm whether charges can affect particle deposition in the airways. Since pharmaceutical aerosol electrostatics is a relatively new research area, much remains to be explored. Thus there is certainly potential for development. New findings in the future may contribute to the advancement of pharmaceutical aerosol formulations and respiratory drug delivery.

Can Condensing Organic Aerosols Lead to Less Cloud Particles?

Science.gov (United States)

Gao, C. Y.; Tsigaridis, K.; Bauer, S.

2017-12-01

We examined the impact of condensing organic aerosols on activated cloud number concentration in a new aerosol microphysics box model, MATRIX-VBS. The model includes the volatility-basis set (VBS) framework in an aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) that resolves aerosol mass and number concentrations and aerosol mixing state. Preliminary results show that by including the condensation of organic aerosols, the new model (MATRIX-VBS) has less activated particles compared to the original model (MATRIX), which treats organic aerosols as non-volatile. Parameters such as aerosol chemical composition, mass and number concentrations, and particle sizes which affect activated cloud number concentration are thoroughly evaluated via a suite of Monte-Carlo simulations. The Monte-Carlo simulations also provide information on which climate-relevant parameters play a critical role in the aerosol evolution in the atmosphere. This study also helps simplifying the newly developed box model which will soon be implemented in the global model GISS ModelE as a module.

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

Czech Academy of Sciences Publication Activity Database

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

2008-01-01

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

The attachment of radon daughters to submicron aerosol particles

International Nuclear Information System (INIS)

Grenier, M.G.; Bigu, J.

1984-04-01

A study of the effects of aerosol concentration, aerosol size distribution and relative humidity on the Working Level and the radon daughter concentration was conducted in a 3000 L radon environmental chamber. Typical values of the aerosol concentration varied in the 1 x 10 3 particles/cm 3 to 4.5 x 10 5 particles/cm 3 range. Various size distributions of aerosols that have mean diffusional aerodynamic diameters of .025 μm, .045 μm and .090 μm were tested. A good correlation was found between the Working Level and the aerosol concentration as well as the relative humidity. Most of the activity seems to be associated with particles of diameter between .05 μm and .2 μm. The results presented here are in agreement with work done by other investigators in the health physics field

Single-particle characterization of the high-Arctic summertime aerosol

Science.gov (United States)

Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

2014-07-01

Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of unknown composition

Single-particle characterization of the High Arctic summertime aerosol

Science.gov (United States)

Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

2014-01-01

Single-particle mass spectrometric measurements were carried out in the High Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real-time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 nm to 3000 nm in diameter showed mass spectrometric patterns indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the High Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a~minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest a presence of a particle type of unknown composition

Single-particle Analyses of Compositions, Morphology, and Viscosity of Aerosol Particles Collected During GoAmazon2014

Science.gov (United States)

Adachi, K.; Gong, Z.; Bateman, A. P.; Martin, S. T.; Cirino, G. G.; Artaxo, P.; Sedlacek, A. J., III; Buseck, P. R.

2014-12-01

Single-particle analysis using transmission electron microscopy (TEM) shows composition and morphology of individual aerosol particles collected during the GoAmazon2014 campaign. These TEM results indicate aerosol types and mixing states, both of which are important for evaluating particle optical properties and cloud condensation nuclei activity. The samples were collected at the T3 site, which is located in the Amazon forest with influences from the urban pollution plume from Manaus. Samples were also collected from the T0 site, which is in the middle of the jungle with minimal to no influences of anthropogenic sources. The aerosol particles mainly originated from 1) anthropogenic pollution (e.g., nanosphere soot, sulfate), 2) biogenic emissions (e.g., primary biogenic particles, organic aerosols), and 3) long-range transport (e.g., sea salts). We found that the biogenic organic aerosol particles contain homogeneously distributed potassium. Particle viscosity is important for evaluating gas-particle interactions and atmospheric chemistry for the particles. Viscosity can be estimated from the rebounding behavior at controlled relative humidities, i.e., highly viscous particles display less rebound on a plate than low-viscosity particles. We collected 1) aerosol particles from a plate (non-rebounded), 2) those that had rebounded from the plate and were then captured onto an adjacent sampling plate, and 3) particles from ambient air using a separate impactor sampler. Preliminary results show that more than 90% of non-rebounded particles consisted of nanosphere soot with or without coatings. The coatings mostly consisted of organic matter. Although rebounded particles also contain nanosphere soot (number fraction 64-69%), they were mostly internally mixed with sulfate, organic matter, or their mixtures. TEM tilted images suggested that the rebounded particles were less deformed on the substrate, whereas the non-rebounded particles were more deformed, which could

Nuclear track radiography of 'hot' aerosol particles

CERN Document Server

Boulyga, S F; Kievets, M K; Lomonosova, E M; Zhuk, I V; Yaroshevich, O I; Perelygin, V P; Petrova, R I; Brandt, R; Vater, P

1999-01-01

Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the alpha-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (gamma,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 9 Pu and sup 2 sup 4 sup 1 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 sup - sup 6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical imag...

Theoretical studies on aerosol agglomeration processes

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K.E.J. [VTT Energy, Espoo (Finland). Energy Use

1997-12-31

In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

Theoretical studies on aerosol agglomeration processes

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K E.J. [VTT Energy, Espoo (Finland). Energy Use

1998-12-31

In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

TSI Model 3936 Scanning Mobility Particle Spectrometer Instrument Handbook

Energy Technology Data Exchange (ETDEWEB)

Kuang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2016-02-01

The Model 3936 Scanning Mobility Particle Spectrometer (SMPS) measures the size distribution of aerosols ranging from 10 nm up to 1000 nm. The SMPS uses a bipolar aerosol charger to keep particles within a known charge distribution. Charged particles are classified according to their electrical mobility, using a long-column differential mobility analyzer (DMA). Particle concentration is measured with a condensation particle counter (CPC). The SMPS is well-suited for applications including: nanoparticle research, atmospheric aerosol studies, pollution studies, smog chamber evaluations, engine exhaust and combustion studies, materials synthesis, filter efficiency testing, nucleation/condensation studies, and rapidly changing aerosol systems.

Aerosol particle transport modeling for preclosure safety studies of nuclear waste repositories

International Nuclear Information System (INIS)

Gelbard, F.

1989-01-01

An important concern for preclosure safety analysis of a nuclear waste repository is the potential release to the environment of respirable aerosol particles. Such particles, less than 10 μm in aerodynamic diameter, may have significant adverse health effects if inhaled. To assess the potential health effects of these particles, it is not sufficient to determine the mass fraction of respirable aerosol. The chemical composition of the particles is also of importance since different radionuclides may pose vastly different health hazards. Thus, models are needed to determine under normal and accident conditions the particle size and the chemical composition distributions of aerosol particles as a function of time and of position in the repository. In this work a multicomponent sectional aerosol model is used to determine the aerosol particle size and composition distributions in the repository. A range of aerosol mass releases with varying mean particle sizes and chemical compositions is used to demonstrate the sensitivities and uncertainties of the model. Decontamination factors for some locations in the repository are presented. 8 refs., 1 tab

Properties of Arctic Aerosol Particles and Residuals of Warm Clouds: Cloud Activation Efficiency and the Aerosol Indirect Effect

Science.gov (United States)

Zelenyuk, A.; Imre, D. G.; Leaitch, R.; Ovchinnikov, M.; Liu, P.; Macdonald, A.; Strapp, W.; Ghan, S. J.; Earle, M. E.

2012-12-01

Single particle mass spectrometer, SPLAT II, was used to characterize the size, composition, number concentration, density, and shape of individual Arctic spring aerosol. Background particles, particles above and below the cloud, cloud droplet residuals, and interstitial particles were characterized with goal to identify the properties that separate cloud condensation nuclei (CCN) from background aerosol particles. The analysis offers a comparison between warm clouds formed on clean and polluted days, with clean days having maximum particle concentrations (Na) lower than ~250 cm-3, as compared with polluted days, in which maximum concentration was tenfold higher. On clean days, particles were composed of organics, organics mixed with sulfates, biomass burning (BB), sea salt (SS), and few soot and dust particles. On polluted days, BB, organics associated with BB, and their mixtures with sulfate dominated particle compositions. Based on the measured compositions and size distributions of cloud droplet residuals, background aerosols, and interstitial particles, we conclude that these three particle types had virtually the same compositions, which means that cloud activation probabilities were surprisingly nearly composition independent. Moreover, these conclusions hold in cases in which less than 20% or more than 90% of background particles got activated. We concluded that for the warm clouds interrogated in this study particle size played a more important factor on aerosol CCN activity. Comparative analysis of all studied clouds reveals that aerosol activation efficiency strongly depends on the aerosol concentrations, such that at Na <200 cm-3, nearly all particles activate, and at higher concentrations the activation efficiency is lower. For example, when Na was greater than 1500 cm-3, less than ~30% of particles activated. The data suggest that as the number of nucleated droplets increases, condensation on existing droplets effectively competes with particle

Nuclear microprobe analysis and source apportionment of individual atmospheric aerosol particles

International Nuclear Information System (INIS)

Artaxo, P.; Rabello, M.L.C.; Watt, F.; Grime, G.; Swietlicki, E.

1993-01-01

In atmospheric aerosol reserach, one key issue is to determine the sources of the airborne particles. Bulk PIXE analysis coupled with receptor modeling provides a useful, but limited view of the aerosol sources influencing one particular site or sample. The scanning nuclear microprobe (SNM) technique is a microanalytical technique that gives unique information on individual aerosol particles. In the SNM analyses a 1.0 μm size 2.4 MeV proton beam from the Oxford SNM was used. The trace elements with Z>11 were measured by the particle induced X-ray emission (PIXE) method with detection limits in the 1-10 ppm range. Carbon, nitrogen and oxygen are measured simultaneously using Rutherford backscattering spectrometry (RBS). Atmospheric aerosol particles were collected at the Brazilian Antarctic Station and at biomass burning sites in the Amazon basin tropical rain forest in Brazil. In the Antarctic samples, the sea-salt aerosol particles were clearly predominating, with NaCl and CaSO 4 as major compounds with several trace elements as Al, Si, P, K, Mn, Fe, Ni, Cu, Zn, Br, Sr, and Pb. Factor analysis of the elemental data showed the presence of four components: 1) Soil dust particles; 2) NaCl particles; 3) CaSO 4 with Sr; and 4) Br and Mg. Strontium, observed at 20-100 ppm levels, was always present in the CaSO 4 particles. The hierarchical cluster procedure gave results similar to the ones obtained through factor analysis. For the tropical rain forest biomass burning aerosol emissions, biogenic particles with a high organic content dominate the particle population, while K, P, Ca, Mg, Zn, and Si are the dominant elements. Zinc at 10-200 ppm is present in biogenic particles rich in P and K. The quantitative aspects and excellent detection limits make SNM analysis of individual aerosol particles a very powerful analytical tool. (orig.)

A recirculation aerosol wind tunnel for evaluating aerosol samplers and measuring particle penetration through protective clothing materials.

Science.gov (United States)

Jaques, Peter A; Hsiao, Ta-Chih; Gao, Pengfei

2011-08-01

A recirculation aerosol wind tunnel was designed to maintain a uniform airflow and stable aerosol size distribution for evaluating aerosol sampler performance and determining particle penetration through protective clothing materials. The oval-shaped wind tunnel was designed to be small enough to fit onto a lab bench, have optimized dimensions for uniformity in wind speed and particle size distributions, sufficient mixing for even distribution of particles, and minimum particle losses. Performance evaluation demonstrates a relatively high level of spatial uniformity, with a coefficient of variation of 1.5-6.2% for wind velocities between 0.4 and 2.8 m s(-1) and, in this range, 0.8-8.5% for particles between 50 and 450 nm. Aerosol concentration stabilized within the first 5-20 min with, approximately, a count median diameter of 135 nm and geometric standard deviation of 2.20. Negligible agglomerate growth and particle loss are suggested. The recirculation design appears to result in unique features as needed for our research.

Single-particle characterization of the high-Arctic summertime aerosol

Directory of Open Access Journals (Sweden)

B. Sierau

2014-07-01

Full Text Available Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS. The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol–cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of

Contributions of Organic Sources to Atmospheric Aerosol Particle Concentrations and Growth

Science.gov (United States)

Russell, L. M.

2017-12-01

Organic molecules are important contributors to aerosol particle mass and number concentrations through primary emissions as well as secondary growth in the atmosphere. New techniques for measuring organic aerosol components in atmospheric particles have improved measurements of this contribution in the last 20 years, including Scanning Transmission X-ray Microscopy Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS), Fourier Transform Infrared spectroscopy (FTIR), and High-Resolution Aerosol Mass Spectrometry (AMS). STXM-NEXAFS individual aerosol particle composition illustrated the variety of morphology of organic components in marine aerosols, the inherent relationships between organic composition and shape, and the links between atmospheric aerosol composition and particles produced in smog chambers. This type of single particle microscopy has also added to size distribution measurements by providing evidence of how surface-controlled and bulk-controlled processes contribute to the growth of particles in the atmosphere. FTIR analysis of organic functional groups are sufficient to distinguish combustion, marine, and terrestrial organic particle sources and to show that each of those types of sources has a surprisingly similar organic functional group composition over four different oceans and four different continents. Augmenting the limited sampling of these off-line techniques with side-by-side inter-comparisons to online AMS provides complementary composition information and consistent quantitative attribution to sources (despite some clear method differences). Single-particle AMS techniques using light scattering and event trigger modes have now also characterized the types of particles found in urban, marine, and ship emission aerosols. Most recently, by combining with off-line techniques, single particle composition measurements have separated and quantified the contributions of organic, sulfate and salt components from ocean biogenic and sea spray

Self-charging of 198Au-labeled monodisperse gold aerosols studied with a miniature electrical mobility spectrometer

International Nuclear Information System (INIS)

Yeh, H.C.; Newton, G.J.; Raabe, O.G.; Boor, D.R.

1976-01-01

Knowledge of the electrostatic character of an aerosol may be essential in assessing its potential inhalation hazard. In inhalation studies with radioactive aerosols, the aerosol charge state may change in the course of transport due to the emission of α, β or γ radiations. This paper describes an experimental study of the self-charging of 198 Au-labeled aerosols of monodisperse gold spheres by β emission. A miniature aerosol electrical mobility spectrometer, suitable for use in inhalation studies with radioactive aerosols, was developed and used in this study. This device is relatively inexpensive, easy to manufacture and its contamination by radioactive material has been minimized. Using polystyrene latex spheres, ranging in diameter from 0.176 to 1.18 μm, the spectrometer was calibrated with flow rates ranging from 400 to 4800 ml/min. Experiments with two sizes of 198 Au-labeled monodisperse gold aerosols were performed. Results indicate that the radioactivity of an aerosol can cause self-charging and affect the charge distribution. (author)

Gravitational agglomeration of post-HCDA LMFBR aerosols: nonspherical particles

International Nuclear Information System (INIS)

Tuttle, R.F.; Loyalka, S.K.

1982-12-01

Aerosol behavior analysis computer programs have shown that temporal aerosol size distributions in nuclear reactor containments are sensitive to shape factors. This research investigates shape factors by a detailed theoretical analysis of hydrodynamic interactions between a nonspherical particle and a spherical particle undergoing gravitational collisions in an LMFBR environment. First, basic definitions and expressions for settling speeds and collisional efficiencies of nonspherical particles are developed. These are then related to corresponding quantities for spherical particles through shape factors. Using volume equivalent diameter as the defining length in the gravitational collision kernel, the aerodynamic shape factor, the density correction factor, and the gravitational collision shape factor, are introduced to describe the collision kernel for collisions between aerosol agglomerates. The Navier-Stokes equation in oblate spheroidal coordinates is solved to model a nonspherical particle and then the dynamic equations for two particle motions are developed. A computer program (NGCEFF) is constructed, and the dynamical equations are solved by Gear's method

Non-ammonium reduced nitrogen species in atmospheric aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Dod, R.L.; Gundel, L.A.; Benner, W.H.; Novakov, T.

1983-08-01

The traditional belief that ambient aerosol particles contain nitrogen predominantly in the form of inorganic ionic species such as NH/sub 4//sup +/ and NO/sub 3//sup -/ was challenged about 10 years ago by results from x-ray photoelectron spectroscopic analysis (ESCA) of California aerosol particles. A significant fraction (approx. 50%) of the reduced nitrogen was observed to have an oxidation state more reduced than ammonium, characteristic of organic nitrogen species. We have used a recently developed thermal evolved gas analysis method (NO/sub x/) in conjunction with ESCA to confirm the existence of these species in aerosol particles collected in both the United States and Europe. The agreement of EGA and ESCA analyses indicates that these species are found not only on the surface but also throughout the particles. 9 references, 6 figures.

Measurement of particle size distribution and mass concentration of nuclear fuel aerosols

International Nuclear Information System (INIS)

Pickering, S.

1982-01-01

The particle size distribution and particle mass concentration of a nuclear fuel aerosol is measured by admitting the aerosol into a vertically-extending container, positioning an alpha particle detector within the container so that its window is horizontal and directed vertically, stopping the admission of aerosol into the container, detecting the alpha-activity of the particles of the aerosol sedimenting onto the detector window (for example in a series of equal time intervals until a constant level is reached), and converting the alpha-activity measurements into particle size distribution and/or particle mass concentration measurements. The detector is attached to a pivotted arm and by raising a counterweight can be lowered from the container for cleaning. (author)

submitter On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation

CERN Document Server

Schobesberger, S; Bianchi, F; Rondo, L; Duplissy, J; Kürten, A; Ortega, I K; Metzger, A; Schnitzhofer, R; Almeida, J; Amorim, A; Dommen, J; Dunne, E M; Ehn, M; Gagné, S; Ickes, L; Junninen, H; Hansel, A; Kerminen, V -M; Kirkby, J; Kupc, A; Laaksonen, A; Lehtipalo, K; Mathot, S; Onnela, A; Petäjä, T; Riccobono, F; Santos, F D; Sipilä, M; Tomé, A; Tsagkogeorgas, G; Viisanen, Y; Wagner, P E; Wimmer, D; Curtius, J; Donahue, N M; Baltensperger, U; Kulmala, M; Worsnop, D R

2015-01-01

The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia $(NH_3)$ and sulfuric acid $(H-2SO_4)$. Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small $NH_3–H_2SO_4$ clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm/Δn = 1.05 and were only observed at sufficiently high $[NH_3]$ / $[H_2SO_4]$. The $H_2SO_4$ molecules of these clusters are partially neutralized by $NH_3$, in close resemblance...

Review: engineering particles using the aerosol-through-plasma method

Energy Technology Data Exchange (ETDEWEB)

Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia C [UNM; Richard, Monique [TEMA

2009-01-01

For decades, plasma processing of materials on the nanoscale has been an underlying enabling technology for many 'planar' technologies, particularly virtually every aspect of modern electronics from integrated-circuit fabrication with nanoscale elements to the newest generation of photovoltaics. However, it is only recent developments that suggest that plasma processing can be used to make 'particulate' structures of value in fields, including catalysis, drug delivery, imaging, higher energy density batteries, and other forms of energy storage. In this paper, the development of the science and technology of one class of plasma production of particulates, namely, aerosol-through-plasma (A-T-P), is reviewed. Various plasma systems, particularly RF and microwave, have been used to create nanoparticles of metals and ceramics, as well as supported metal catalysts. Gradually, the complexity of the nanoparticles, and concomitantly their potential value, has increased. First, unique two-layer particles were generated. These were postprocessed to create unique three-layer nanoscale particles. Also, the technique has been successfully employed to make other high-value materials, including carbon nanotubes, unsupported graphene, and spherical boron nitride. Some interesting plasma science has also emerged from efforts to characterize and map aerosol-containing plasmas. For example, it is clear that even a very low concentration of particles dramatically changes plasma characteristics. Some have also argued that the local-thermodynamic-equilibrium approach is inappropriate to these systems. Instead, it has been suggested that charged- and neutral-species models must be independently developed and allowed to 'interact' only in generation terms.

Microphysical processing of aerosol particles in orographic clouds

Directory of Open Access Journals (Sweden)

S. Pousse-Nottelmann

2015-08-01

aerosol cycling in clouds has been implemented into COSMO-Model, the regional weather forecast and climate model of the Consortium for Small-scale Modeling (COSMO. The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed us to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener–Bergeron–Findeisen (WBF process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snowflakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snowflakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. Thereby, the processes impact the total aerosol number and mass and additionally alter the shape of the aerosol size distributions by enhancing the internally mixed/soluble Aitken and accumulation mode and generating coarse-mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases the cloud droplet number concentration with possible implications for the ice crystal number

Hygroscopic growth of atmospheric aerosol particles and its relation to nucleation scavenging in clouds

Energy Technology Data Exchange (ETDEWEB)

Svenningsson, B.

1997-11-01

Aerosol particles in the atmosphere are important in several aspects. Some major aerosol constituents that are deposited in ecosystems are acidic or fertilizers and some minor or trace constituents are toxic. Aerosol particles are also involved in the earth`s radiation balance, both directly by scattering the sunlight and indirectly by influencing the clouds. All these effects are influenced by the interaction between the aerosol particles and water vapour. A tandem differential mobility analyser (TDMA) has been designed to measure hygroscopic growth, i.e. the particle diameter change due to uptake of water at well defined relative humidities below 100%. Tests of the instrument performance have been made using aerosol particles of pure inorganic salts. Three field experiments have been performed as parts of large fog and cloud experiments. Bimodal hygroscopic growth spectra were found: less-hygroscopic particles containing a few percent and more-hygroscopic particles around 50% by volume of hygroscopically active material. In general the fraction of less-hygroscopic particles decreases with particle size and it is larger in polluted continental aerosols than in remote background aerosols. This external mixing cannot be fully understood using present views on the formation of aerosols. Evidence or the importance of the external mixing on the cloud nucleating properties of the particles are found in comparisons between hygroscopic growth spectra for the total aerosol, the interstitial aerosol in clouds, and cloud drop residuals. Cloud condensation nuclei spectra, calculated using aerosol particle size distributions and hygroscopic growth spectra, in combination with information on the major inorganic ions are presented. These CCN spectra reveal for instance that the influence of less-hygroscopic particles on the cloud droplets increases with increasing peak supersaturation. The fraction of the particles that were scavenged to cloud drops, as a function of particle

Synthesis of nanosized metal particles from an aerosol

Directory of Open Access Journals (Sweden)

Srećko R. Stopić

2013-10-01

Full Text Available The synthesis of metallic nanoparticles from the precursor solution of salts using the ultrasonic spray pyrolysis method was considered in this work. During the control of process parameters (surface tension and density, the concentration of solution, residence time of aerosol in the reactor, presence of additives, gas flow rate, decomposition temperature of aerosol, type of precursor and working atmosphere it is possible to guide the process in order to obtain powders with such a morphology which satisfies more complex requirements for the desired properties of advanced engineering materials.  Significant advance in the improvement of powder characteristics (lower particles sizes, better spheroidity, higher surface area was obtained by the application of the ultrasonic generator for the preparation of aerosols. Ultrasonic spray pyrolysis is performed by the action of a powerful source of ultrasound on the corresponding precursor solution forming the aerosol with a constant droplet size, which depends on the characteristics of liquid and the frequency of ultrasound. The produced aerosols were transported into the hot reactor, which enables the reaction to occur in a very small volume of a particle and formation of  nanosized powder. Spherical, nanosized particles of metals (Cu, Ag, Au, Co were produced with new and improved physical and chemical characteristics at the IME, RWTH Aachen University. The high costs associated with small quantities of produced nanosized particles represent a limitation of the USP-method. Therefore, scale up of the ultrasonic spray pyrolysis was performed as a final target in the synthesis of nanosized powder.

Measurements of Primary Biogenic Aerosol Particles with an Ultraviolet Aerodynamic Particle Sizer (UVAPS) During AMAZE-08

Science.gov (United States)

Wollny, A. G.; Garland, R.; Pöschl, U.

2008-12-01

Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the AMazonian Aerosol CharacteriZation Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. The presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 μm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as 'viable aerosols' or 'fluorescent bioparticles' (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. First data analyses show a pronounced peak of FBAP at diameters around 2-3 μm. In this size range the biogenic particle fraction was

The dynamics of a charged particle

OpenAIRE

Rohrlich, Fritz

2008-01-01

Using physical arguments, I derive the physically correct equations of motion for a classical charged particle from the Lorentz-Abraham-Dirac equations (LAD) which are well known to be physically incorrect. Since a charged particle can classically not be a point particle because of the Coulomb field divergence, my derivation accounts for that by imposing a basic condition on the external force. That condition ensures that the particle's finite size charge distribution looks like a point charg...

Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

Directory of Open Access Journals (Sweden)

E. Asmi

2010-05-01

Full Text Available The Antarctic near-coastal sub-micrometre aerosol particle features in summer were characterised based on measured data on aerosol hygroscopicity, size distributions, volatility and chemical ion and organic carbon mass concentrations. Hysplit model was used to calculate the history of the air masses to predict the particle origin. Additional measurements of meteorological parameters were utilised. The hygroscopic properties of particles mostly resembled those of marine aerosols. The measurements took place at 130 km from the Southern Ocean, which was the most significant factor affecting the particle properties. This is explained by the lack of additional sources on the continent of Antarctica. The Southern Ocean was thus a likely source of the particles and nucleating and condensing vapours. The particles were very hygroscopic (HGF 1.75 at 90 nm and very volatile. Most of the sub-100 nm particle volume volatilised below 100 °C. Based on chemical data, particle hygroscopic and volatile properties were explained by a large fraction of non-neutralised sulphuric acid together with organic material. The hygroscopic growth factors assessed from chemical data were similar to measured. Hygroscopicity was higher in dry continental air masses compared with the moist marine air masses. This was explained by the aging of the marine organic species and lower methanesulphonic acid volume fraction together with the changes in the inorganic aerosol chemistry as the aerosol had travelled long time over the continental Antarctica. Special focus was directed in detailed examination of the observed new particle formation events. Indications of the preference of negative over positive ions in nucleation could be detected. However, in a detailed case study, the neutral particles dominated the particle formation process. Freshly nucleated particles had the smallest hygroscopic growth factors, which increased subsequent to particle aging.

Aerosolization, Chemical Characterization, Hygroscopicity and Ice Formation of Marine Biogenic Particles

Science.gov (United States)

Alpert, P. A.; Radway, J.; Kilthau, W.; Bothe, D.; Knopf, D. A.; Aller, J. Y.

2013-12-01

The oceans cover the majority of the earth's surface, host nearly half the total global primary productivity and are a major source of atmospheric aerosol particles. However, effects of biological activity on sea spray generation and composition, and subsequent cloud formation are not well understood. Our goal is to elucidate these effects which will be particularly important over nutrient rich seas, where microorganisms can reach concentrations of 10^9 per mL and along with transparent exopolymer particles (TEP) can become aerosolized. Here we report the results of mesocosm experiments in which bubbles were generated by two methods, either recirculating impinging water jets or glass frits, in natural or artificial seawater containing bacteria and unialgal cultures of three representative phytoplankton species, Thalassiosira pseudonana, Emiliania huxleyi, and Nannochloris atomus. Over time we followed the size distribution of aerosolized particles as well as their hygroscopicity, heterogeneous ice nucleation potential, and individual physical-chemical characteristics. Numbers of cells and the mass of dissolved and particulate organic carbon (DOC, POC), TEP (which includes polysaccharide-containing microgels and nanogels >0.4 μm in diameter) were determined in the bulk water, the surface microlayer, and aerosolized material. Aerosolized particles were also impacted onto substrates for ice nucleation and water uptake experiments, elemental analysis using computer controlled scanning electron microscopy and energy dispersive analysis of X-rays (CCSEM/EDX), and determination of carbon bonding with scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Regardless of bubble generation method, the overall concentration of aerosol particles, TEP, POC and DOC increased as concentrations of bacterial and phytoplankton cells increased, stabilized, and subsequently declined. Particles cloud formation and potential

Time Resolved Measurements of Primary Biogenic Aerosol Particles in Amazonia

Science.gov (United States)

Wollny, A. G.; Garland, R.; Pöschl, U.

2009-04-01

Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the Amazonian Aerosol Characterization Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. This presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 µm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as "viable aerosols" or "fluorescent bioparticles" (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. Data from the UVAPS were averaged over 5 minute time intervals. The presence of bioparticles in the observed size range has been

Reactions and mass spectra of complex particles using Aerosol CIMS

Science.gov (United States)

Hearn, John D.; Smith, Geoffrey D.

2006-12-01

Aerosol chemical ionization mass spectrometry (CIMS) is used both on- and off-line for the analysis of complex laboratory-generated and ambient particles. One of the primary advantages of Aerosol CIMS is the low degree of ion fragmentation, making this technique well suited for investigating the reactivity of complex particles. To demonstrate the usefulness of this "soft" ionization, particles generated from meat cooking were reacted with ozone and the composition was monitored as a function of reaction time. Two distinct kinetic regimes were observed with most of the oleic acid in these particles reacting quickly but with 30% appearing to be trapped in the complex mixture. Additionally, detection limits are measured to be sufficiently low (100-200 ng/m3) to detect some of the more abundant constituents in ambient particles, including sulfate, which is measured in real-time at 1.2 [mu]g/m3. To better characterize complex aerosols from a variety of sources, a novel off-line collection method was also developed in which non-volatile and semi-volatile organics are desorbed from particles and concentrated in a cold U-tube. Desorption from the U-tube followed by analysis with Aerosol CIMS revealed significant amounts of nicotine in cigarette smoke and levoglucosan in oak and pine smoke, suggesting that this may be a useful technique for monitoring particle tracer species. Additionally, secondary organic aerosol formed from the reaction of ozone with R-limonene and volatile organics from orange peel were analyzed off-line showing large molecular weight products (m/z > 300 amu) that may indicate the formation of oligomers. Finally, mass spectra of ambient aerosol collected offline reveal a complex mixture of what appears to be highly processed organics, some of which may contain nitrogen.

Papers of the 15. french congress on the aerosols CFA 99; Actes du 15. congres francais sur les aerosols CFA 99

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This french congress on the aerosols took place in Paris the 8 and 9 december 1999. It was presented in four main themes: bio-aerosols and filtering; the aerosols metrology; the aerosols in the environment; aerosols physic and applications. Seven papers have been analyzed in INIS data base for their specific interest in the nuclear industry. They concern the aerosol capture simulation, the aerosols sampling in workplace environment, a ring-effect ion generator development for the charge and the neutralization of an aerosol cloud, the radon 222 characterization in a house, a particle re-entrainment, the electrical charge process of beta emitter radioactive aerosols, the simulation of air flows in many filters. The other ones are analyzed in the ETDE data base. (A.L.B.)

Charged particle accelerator

Energy Technology Data Exchange (ETDEWEB)

Ress, T I; Nolde, G V

1974-11-25

A charged particle accelerator is described. It is made of an enclosure arranged for channeling a stream of charged particles along a predetermined path, and propelling means juxtaposed to the enclosure for generating a magnetic field moving in a predetermined direction with respect to each point of the path, the magnetic flux vector of that field being transverse to that path at every point, which gives the particles, along said path, a velocity connected to that of the mobile field by a predetermined relation. This can be applied to the fast production of chemical compounds, to the emission of neutrons and of thermal energy, and to the production of mechanical energy for propelling space ships.

Charged particle accelerator

International Nuclear Information System (INIS)

Ress, T.I.; Nolde, G.V.

1974-01-01

A charged particle accelerator is described. It is made of an enclosure arranged for channeling a stream of charged particles along a predetermined path, and propelling means juxtaposed to said enclosure for generating therein a magnetic field moving in a predetermined direction with respect to each point of said path, the magnetic flux vector of that field being transverse to that path at every point, which gives the particles, along said path, a velocity connected to that of the mobile field by a predetermined relation. This can be applied to the fast production of chemical compounds, to the emission of neutrons and of thermal energy, and to the production of mechanical energy for propelling space ships [fr

Charge interaction between particle-laden fluid interfaces.

Science.gov (United States)

Xu, Hui; Kirkwood, John; Lask, Mauricio; Fuller, Gerald

2010-03-02

Experiments are described where two oil/water interfaces laden with charged particles move at close proximity relative to one another. The particles on one of the interfaces were observed to be attracted toward the point of closest approach, forming a denser particle monolayer, while the particles on the opposite interface were repelled away from this point, forming a particle depletion zone. Such particle attraction/repulsion was observed even if one of the interfaces was free of particles. This phenomenon can be explained by the electrostatic interaction between the two interfaces, which causes surface charges (charged particles and ions) to redistribute in order to satisfy surface electric equipotential at each interface. In a forced particle oscillation experiment, we demonstrated the control of charged particle positions on the interface by manipulating charge interaction between interfaces.

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

Science.gov (United States)

Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; Amorim Holanda, Bruna; Artaxo, Paulo; Barbosa, Henrique M. J.; Borrmann, Stephan; Cecchini, Micael A.; Costa, Anja; Dollner, Maximilian; Fütterer, Daniel; Järvinen, Emma; Jurkat, Tina; Klimach, Thomas; Konemann, Tobias; Knote, Christoph; Krämer, Martina; Krisna, Trismono; Machado, Luiz A. T.; Mertes, Stephan; Minikin, Andreas; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Sauer, Daniel; Schlager, Hans; Schnaiter, Martin; Schneider, Johannes; Schulz, Christiane; Spanu, Antonio; Sperling, Vinicius B.; Voigt, Christiane; Walser, Adrian; Wang, Jian; Weinzierl, Bernadett; Wendisch, Manfred; Ziereis, Helmut

2018-01-01

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September-October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable

Inverse problem for particle size distributions of atmospheric aerosols using stochastic particle swarm optimization

International Nuclear Information System (INIS)

Yuan Yuan; Yi Hongliang; Shuai Yong; Wang Fuqiang; Tan Heping

2010-01-01

As a part of resolving optical properties in atmosphere radiative transfer calculations, this paper focuses on obtaining aerosol optical thicknesses (AOTs) in the visible and near infrared wave band through indirect method by gleaning the values of aerosol particle size distribution parameters. Although various inverse techniques have been applied to obtain values for these parameters, we choose a stochastic particle swarm optimization (SPSO) algorithm to perform an inverse calculation. Computational performances of different inverse methods are investigated and the influence of swarm size on the inverse problem of computation particles is examined. Next, computational efficiencies of various particle size distributions and the influences of the measured errors on computational accuracy are compared. Finally, we recover particle size distributions for atmospheric aerosols over Beijing using the measured AOT data (at wavelengths λ=0.400, 0.690, 0.870, and 1.020 μm) obtained from AERONET at different times and then calculate other AOT values for this band based on the inverse results. With calculations agreeing with measured data, the SPSO algorithm shows good practicability.

The effect of actuator nozzle designs on the electrostatic charge generated in pressurised metered dose inhaler aerosols.

Science.gov (United States)

Chen, Yang; Young, Paul M; Fletcher, David F; Chan, Hak Kim; Long, Edward; Lewis, David; Church, Tanya; Traini, Daniela

2015-04-01

To investigate the influence of different actuator nozzle designs on aerosol electrostatic charges and aerosol performances for pressurised metered dose inhalers (pMDIs). Four actuator nozzle designs (flat, curved flat, cone and curved cone) were manufactured using insulating thermoplastics (PET and PTFE) and conducting metal (aluminium) materials. Aerosol electrostatic profiles of solution pMDI formulations containing propellant HFA 134a with different ethanol concentration and/or model drug beclomethasone dipropionate (BDP) were studied using a modified electrical low-pressure impactor (ELPI) for all actuator designs and materials. The mass of the deposited drug was analysed using high performance liquid chromatography (HPLC). Both curved nozzle designs for insulating PET and PTFE actuators significantly influenced aerosol electrostatics and aerosol performance compared with conducting aluminium actuator, where reversed charge polarity and higher throat deposition were observed with pMDI formulation containing BDP. Results are likely due to the changes in plume geometry caused by the curved edge nozzle designs and the bipolar charging nature of insulating materials. This study demonstrated that actuator nozzle designs could significantly influence the electrostatic charges profiles and aerosol drug deposition pattern of pMDI aerosols, especially when using insulating thermoplastic materials where bipolar charging is more dominant.

Scintillation Detectors for Charged Particles and Photons

CERN Document Server

Lecoq, P

2011-01-01

Scintillation Detectors for Charged Particles and Photons in 'Charged Particle Detectors - Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Subsection '3.1.1 Scintillation Detectors for Charged Particles and Photons' of Section '3.1 Charged Particle Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.1.1 Scintillation Detectors for Charged Particles and Photons 3.1.1.1 Basic detector principles and scintillator requirements 3.1.1.1.1 Interaction of ionizing radiation with scintillator material 3.1.1.1.2 Important scint...

Characterization of aerosol particles at the forested site in Lithuania

Science.gov (United States)

Rimselyte, I.; Garbaras, A.; Kvietkus, K.; Remeikis, V.

2009-04-01

Atmospheric particulate matter (PM), especially fine particles (particles with aerodynamic diameter less than 1 m, PM1), has been found to play an important role in global climate change, air quality, and human health. The continuous study of aerosol parameters is therefore imperative for better understanding the environmental effects of the atmospheric particles, as well as their sources, formation and transformation processes. The particle size distribution is particularly important, since this physical parameter determines the mass and number density, lifetime and atmospheric transport, or optical scattering behavior of the particles in the atmosphere (Jaenicke, 1998). Over the years several efforts have been made to improve the knowledge about the chemical composition of atmospheric particles as a function of size (Samara and Voutsa, 2005) and to characterize the relative contribution of different components to the fine particulate matter. It is well established that organic materials constitute a highly variable fraction of the atmospheric aerosol. This fraction is predominantly found in the fine size mode in concentrations ranging from 10 to 70% of the total dry fine particle mass (Middlebrook et al., 1998). Although organic compounds are major components of the fine particles, the composition, formation mechanism of organic aerosols are not well understood. This is because particulate organic matter is part of a complex atmospheric system with hundreds of different compounds, both natural and anthropogenic, covering a wide range of chemical properties. The aim of this study was to characterize the forest PM1, and investigate effects of air mass transport on the aerosol size distribution and chemical composition, estimate and provide insights into the sources and characteristics of carbonaceous aerosols through analysis ^13C/12C isotopic ratio as a function of the aerosol particles size. The measurements were performed at the Rugšteliškis integrated

Particle-Resolved Modeling of Aerosol Mixing State in an Evolving Ship Plume

Science.gov (United States)

Riemer, N. S.; Tian, J.; Pfaffenberger, L.; Schlager, H.; Petzold, A.

2011-12-01

The aerosol mixing state is important since it impacts the particles' optical and CCN properties and thereby their climate impact. It evolves continuously during the particles' residence time in the atmosphere as a result of coagulation with other particles and condensation of secondary aerosol species. This evolution is challenging to represent in traditional aerosol models since they require the representation of a multi-dimensional particle distribution. While modal or sectional aerosol representations cannot practically resolve the aerosol mixing state for more than a few species, particle-resolved models store the composition of many individual aerosol particles directly. They thus sample the high-dimensional composition state space very efficiently and so can deal with tens of species, fully resolving the mixing state. Here we use the capabilities of the particle-resolved model PartMC-MOSAIC to simulate the evolution of particulate matter emitted from marine diesel engines and compare the results to aircraft measurements made in the English Channel in 2007 as part of the European campaign QUANTIFY. The model was initialized with values of gas concentrations and particle size distributions and compositions representing fresh ship emissions. These values were obtained from a test rig study in the European project HERCULES in 2006 using a serial four-stroke marine diesel engine operating on high-sulfur heavy fuel oil. The freshly emitted particles consisted of sulfate, black carbon, organic carbon and ash. We then tracked the particle population for several hours as it evolved undergoing coagulation, dilution with the background air, and chemical transformations in the aerosol and gas phase. This simulation was used to compute the evolution of CCN properties and optical properties of the plume on a per-particle basis. We compared our results to size-resolved data of aged ship plumes from the QUANTIFY Study in 2007 and showed that the model was able to reproduce

Charged Particle Radiography

International Nuclear Information System (INIS)

Morris, Chris

2004-01-01

The Coulomb multiple scattering of charged particles as they pass through material allows them to be used as a radiographic probe. This forms the basis for a new kind of radiography that is finding application where conventional x-ray radiography is limited by flux or backgrounds. Charged-particle radiography is providing a versatile new probe that has advantages over conventional x-ray radiography for some unique application. Proton radiography has been used to make quantitative motion pictures of high explosive driven experiments and proves to be of great value for radiographing experiments that mock up nuclear weapon primaries for stockpile certification. By taking advantage of magnetic lens to magnify images and by using the very bright beams that can be made with electrons, charged-particle radiography may be useful for studying the fine spatial detail and very fast motion in laser driven implosion experiments at the National Ignition Facility. Finally, radiographs can be made using cosmic-ray muons for searching vehicles and cargo containers for surreptitious cargo of high z materials such as uranium or plutonium.

Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles

Science.gov (United States)

Schiebel, Thea; Höhler, Kristina; Funk, Roger; Hill, Thomas C. J.; Levin, Ezra J. T.; Nadolny, Jens; Steinke, Isabelle; Suski, Kaitlyn J.; Ullrich, Romy; Wagner, Robert; Weber, Ines; DeMott, Paul J.; Möhler, Ottmar

2016-04-01

Recent investigations at the cloud simulation chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) suggest that agricultural soil dust has an ice nucleation ability that is enhanced up to a factor of 10 compared to desert dust, especially at temperatures above -26 °C (Steinke et al., in preparation for submission). This enhancement might be caused by the contribution of very ice-active biological particles. In addition, soil dust aerosol particles often contain a considerably higher amount of organic matter compared to desert dust particles. To test agricultural soil dust as a source of ice nucleating particles, especially for ice formation in warm clouds, we conducted a series of laboratory measurements with different soil dust samples to extend the existing AIDA dataset. The AIDA has a volume of 84 m3 and operates under atmospherically relevant conditions over wide ranges of temperature, pressure and humidity. By controlled adiabatic expansions, the ascent of an air parcel in the troposphere can be simulated. As a supplement to the AIDA facility, we use the INKA (Ice Nucleation Instrument of the KArlsruhe Institute of Technology) continuous flow diffusion chamber based on the design by Rogers (1988) to expose the sampled aerosol particles to a continuously increasing saturation ratio by keeping the aerosol temperature constant. For our experiments, soil dust was dry dispersed into the AIDA vessel. First, fast saturation ratio scans at different temperatures were performed with INKA, sampling soil dust aerosol particles directly from the AIDA vessel. Then, we conducted the AIDA expansion experiment starting at a preset temperature. The combination of these two different methods provides a robust data set on the temperature-dependent ice activity of various agriculture soil dust aerosol particles with a special focus on relatively high temperatures. In addition, to extend the data set, we investigated the role of biological and organic matter in more

Molecular dynamics simulations of laser disintegration of amorphous aerosol particles with spatially nonuniform absorption

International Nuclear Information System (INIS)

Schoolcraft, Tracy A.; Constable, Gregory S.; Jackson, Bryan; Zhigilei, Leonid V.; Garrison, Barbara J.

2001-01-01

A series of molecular dynamics (MD) simulations are performed in order to provide qualitative information on the mechanisms of disintegration of aerosol particles as used in aerosol mass spectrometry. Three generic types of aerosol particles are considered: strongly absorbing particles with homogeneous composition, transparent particles with absorbing inclusion, and absorbing particles with transparent inclusion. To study the effect of the mechanical properties of the aerosol material on the disintegration process, the results for crystalline (brittle) and amorphous (ductile) particles are compared. For large laser fluences, nearly complete dissociation of the absorbing material is observed, whereas the nonabsorbing portions remain fairly intact. Because large fluences can cause photofragmentation of constituent molecules, multiple pulses at low laser fluence and/or lasers with different wavelengths are recommended for the best representative sampling of multicomponent aerosol particles in laser desorption/ionization (LDI) mass spectrometry

Physicochemical characterization of Capstone depleted uranium aerosols I: uranium concentration in aerosols as a function of time and particle size.

Science.gov (United States)

Parkhurst, Mary Ann; Cheng, Yung Sung; Kenoyer, Judson L; Traub, Richard J

2009-03-01

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65

Characteristics of agglomerates of sodium oxide aerosol particles: Task 7, topical report

International Nuclear Information System (INIS)

Gieseke, J.A.; Reed, L.D.; Jordan, H.; Lee, K.W.

1977-01-01

Accurate macroscopic predictions of aerosol population behavior within enclosed containments are known to depend strongly upon the microscopic characteristics of the individual aerosols. Also, coagulation rates due to mechanisms which produce relative motions between particles within the suspended aerosol are known to depend upon the cross sectional areas of the individual particles. Hence, it has been the primary concern of this study to examine experimentally the microscopic characteristics of sodium oxide aerosols produced in air. The results of these measurements can now be incorporated into the various macroscopic aerosol behavior prediction models

Influences of aerosol physiochemical properties and new particle formation on CCN activity from observation at a suburban site of China

Science.gov (United States)

Li, Yanan; Zhang, Fang; Li, Zhanqing; Sun, Li; Wang, Zhenzhu; Li, Ping; Sun, Yele; Ren, Jingye; Wang, Yuying; Cribb, Maureen; Yuan, Cheng

2017-05-01

With the aim of understanding the impact of aerosol particle size and chemical composition on CCN activity, the size-resolved cloud condensation nuclei (CCN) number concentration (NCCN), particle number size distribution (PSD) (10-600 nm), and bulk chemical composition of particles with a diameter China, from 22 July to 26 August 2014. The NCCN was measured at five different supersaturations (SS) ranging from 0.075%-0.76%. Diurnal variations in the aerosol number concentration (NCN), NCCN, the bulk aerosol activation ratio (AR), the hygroscopicity parameter (κchem), and the ratio of 44 mass to charge ration (m/z 44) to total organic signal in the component spectrum (f44), and the PSD were examined integrally to study the influence of particle size and chemical composition on CCN activation. We found that particle size was more related to the CCN activation ratios in the morning, whereas in the afternoon ( 1400 LST), κchem and f44 were more closely associated with the bulk AR. Assuming the internal mixing of aerosol particles, NCCN was estimated using the bulk chemical composition and real-time PSD. We found that the predicted CCN number concentrations were underestimated by 20-30% at SS case during non-NPF event. It has been found that CCN activation was restrained at the ;growth; stage during which larger particle diameters were needed to reach an activation diameter(Da), and the bulk AR decreased as well. However, during the ;leveling-off; stage, a lower Da was observed and CCN activation was greatly enhanced.

Nuclear track radiography of 'hot' aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Boulyga, S.F.; Kievitskaja, A.I.; Kievets, M.K.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Perelygin, V.P.; Petrova, R.; Brandt, R.; Vater, P

1999-06-01

Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the {alpha}-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and ({gamma},f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by {sup 235}U, {sup 239}Pu and {sup 241}Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10{sup -6} Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of 'hot' particles00.

Scattering of aerosol particles by a Hermite-Gaussian beam in marine atmosphere.

Science.gov (United States)

Huang, Qingqing; Cheng, Mingjian; Guo, Lixin; Li, Jiangting; Yan, Xu; Liu, Songhua

2017-07-01

Based on the complex-source-point method and the generalized Lorenz-Mie theory, the scattering properties and polarization of aerosol particles by a Hermite-Gaussian (HG) beam in marine atmosphere is investigated. The influences of beam mode, beam width, and humidity on the scattered field are analyzed numerically. Results indicate that when the number of HG beam modes u (v) increase, the radar cross section of aerosol particles alternating appears at maximum and minimum values in the forward and backward scattering, respectively, because of the special petal-shaped distribution of the HG beam. The forward and backward scattering of aerosol particles decreases with the increase in beam waist. When beam waist is less than the radius of the aerosol particle, a minimum value is observed in the forward direction. The scattering properties of aerosol particles by the HG beam are more sensitive to the change in relative humidity compared with those by the plane wave and the Gaussian beam (GB). The HG beam shows superiority over the plane wave and the GB in detecting changes in the relative humidity of marine atmosphere aerosol. The effects of relative humidity on the polarization of the HG beam have been numerically analyzed in detail.

Discrete element method modeling of the triboelectric charging of polyethylene particles: Can particle size distribution and segregation reduce the charging?

International Nuclear Information System (INIS)

Konopka, Ladislav; Kosek, Juraj

2015-01-01

Polyethylene particles of various sizes are present in industrial gas-dispersion reactors and downstream processing units. The contact of the particles with a device wall as well as the mutual particle collisions cause electrons on the particle surface to redistribute in the system. The undesirable triboelectric charging results in several operational problems and safety risks in industrial systems, for example in the fluidized-bed polymerization reactor. We studied the charging of polyethylene particles caused by the particle-particle interactions in gas. Our model employs the Discrete Element Method (DEM) describing the particle dynamics and incorporates the ‘Trapped Electron Approach’ as the physical basis for the considered charging mechanism. The model predicts the particle charge distribution for systems with various particle size distributions and various level of segregation. Simulation results are in a qualitative agreement with experimental observations of similar particulate systems specifically in two aspects: 1) Big particles tend to gain positive charge and small particles the negative one. 2) The wider the particle size distribution is, the more pronounced is the charging process. Our results suggest that not only the size distribution, but also the effect of the spatial segregation of the polyethylene particles significantly influence the resulting charge distribution ‘generated’ in the system. The level of particle segregation as well as the particle size distribution of polyethylene particles can be in practice adjusted by the choice of supported catalysts, by the conditions in the fluidized-bed polymerization reactor and by the fluid dynamics. We also attempt to predict how the reactor temperature affects the triboelectric charging of particles. (paper)

Polyhexamethylene guanidine phosphate aerosol particles induce pulmonary inflammatory and fibrotic responses.

Science.gov (United States)

Kim, Ha Ryong; Lee, Kyuhong; Park, Chang We; Song, Jeong Ah; Shin, Da Young; Park, Yong Joo; Chung, Kyu Hyuck

2016-03-01

Polyhexamethylene guanidine (PHMG) phosphate was used as a disinfectant for the prevention of microorganism growth in humidifiers, without recognizing that a change of exposure route might cause significant health effects. Epidemiological studies reported that the use of humidifier disinfectant containing PHMG-phosphate can provoke pulmonary fibrosis. However, the pulmonary toxicity of PHMG-phosphate aerosol particles is unknown yet. This study aimed to elucidate the toxicological relationship between PHMG-phosphate aerosol particles and pulmonary fibrosis. An in vivo nose-only exposure system and an in vitro air-liquid interface (ALI) co-culture model were applied to confirm whether PHMG-phosphate induces inflammatory and fibrotic responses in the respiratory tract. Seven-week-old male Sprague-Dawley rats were exposed to PHMG-phosphate aerosol particles for 3 weeks and recovered for 3 weeks in a nose-only exposure chamber. In addition, three human lung cells (Calu-3, differentiated THP-1 and HMC-1 cells) were cultured at ALI condition for 12 days and were treated with PHMG-phosphate at set concentrations and times. The reactive oxygen species (ROS) generation, airway barrier injuries and inflammatory and fibrotic responses were evaluated in vivo and in vitro. The rats exposed to PHMG-phosphate aerosol particles in nanometer size showed pulmonary inflammation and fibrosis including inflammatory cytokines and fibronectin mRNA increase, as well as histopathological changes. In addition, PHMG-phosphate triggered the ROS generation, airway barrier injuries and inflammatory responses in a bronchial ALI co-culture model. Those results demonstrated that PHMG-phosphate aerosol particles cause pulmonary inflammatory and fibrotic responses. All features of fibrogenesis by PHMG-phosphate aerosol particles closely resembled the pathology of fibrosis that was reported in epidemiological studies. Finally, we expected that PHMG-phosphate infiltrated into the lungs in the form of

Shortwave radiative effects of unactivated aerosol particles in clouds

International Nuclear Information System (INIS)

Ackerman, T.; Baker, M.B.

1977-01-01

Clouds in some polluted areas may contain high concentrations of anthropogenic aerosol particles. The possible role of these particles in perturbing the optical and dynamical properties of the clouds is an important question for climate studies. The direct radiative effects of unactivated aerosol particles in stable stratus clouds have been calculated at lambda=0.5μm. Several simplifying asumptions have been made relating the behavior of such particles in the high humidity enviornment within the cloud to their physicochemical make-up. It is shown that the energy absorbed by particles within the clouds may be, for realistic concentrations, comparable to the latent heat released and thus may play a significant role in cloud dynamics in some areas. These results are shown to be relatively insensitive to the assumptions about the particle properties within the cloud

Sources for charged particles

International Nuclear Information System (INIS)

Arianer, J.

1997-01-01

This document is a basic course on charged particle sources for post-graduate students and thematic schools on large facilities and accelerator physics. A simple but precise description of the creation and the emission of charged particles is presented. This course relies on every year upgraded reference documents. Following relevant topics are considered: electronic emission processes, technological and practical considerations on electron guns, positron sources, production of neutral atoms, ionization, plasma and discharge, different types of positive and negative ion sources, polarized particle sources, materials for the construction of ion sources, low energy beam production and transport. (N.T.)

Determination of Aerosol Particle Diameter Using Cascade Impactor Procedure

International Nuclear Information System (INIS)

Bunawas; Ruslanto, P. O

1998-01-01

Determination of aerosol particle size distribution has been done using a low pressure Andersen's cascade impactor with 13 stages. The aerosol has been sampled with flow rate of aerosol sampling of 28.3 Ipm. Preliminary study result shows that aerosol in the simulation chamber was spread in monomodal distribution with Mass Median Aerodynamic Diameter of 4.9 μm. The aerosol measurement in Japan Power Demonstration Reactor has been spread in trimodal distribution with Activity Median Aerodynamic Diameter equal to 13.3 μm. The use of mylar as impaction plate instead of aluminum foil gives good result

The effect of changes in humidity on the size of submicron aerosols

International Nuclear Information System (INIS)

Phillips, C.R.; Khan, A.

1987-06-01

The effect of humidity on inhaled aerosols in the respiratory tract is to cause an increase in particle size of up to several times if the aerosol particle is hygroscopic. The presence of ionizing radiation and air ions (for example, from uranium and radon/thoron) increases the tendency of water vapour to nucleate. The desposition of particles in the lung is enhanced by high charge density (>10 charges/particle). Radon has been reported to play an important role in the formation of sulphate and nitrate particles in the atmosphere. A detailed overview of the effect of humidity on aerosols is presented in the present work. Results of experimental measurements made on NaCl (hygroscopic) and kerosene combustion (hydrophobic) aerosols under ambient and humid conditions are reported. Initial aerosol conditions were 20 degrees C and 35% R.H. Final aerosol conditions were maintained at 37 degrees C and 100% R.H. in order to simulate the conditions inside the respiratory tract. An average growth factor of 1.9 ± 0.4 (standard deviation) was observed for the NaCl aerosol and 1.3 ± 0.2 (standard deviation) for the kerosene aerosol. For the activity size distribution, however, the NaCl aerosols were observed to grow by an average factor of only 1.2 ± 0.1 (standard deviation) whereas the kerosene aerosols grew by a factor of 1.3 ± 0.2 (standard deviation)

Charging and coagulation of water aerosols with negligible addition of high-radioactive droplets

International Nuclear Information System (INIS)

Vasil'eva, N.L.; Sedova, G.L.; Chernyj, L.T.

1994-01-01

The mechanics of electrocoagulation of water aerosols with negligible admixture of high-radioactive droplets is considered. A corresponding mathematical model has been worked out which describes the processes of ionization, electrification and coagulation of radioactive aerosols. Numerical studies are carried out for a series of typical aerosols on the time dependence of ion concentrations, charge and pure droplet concentrations, as well as the charge and radius of radioactive droplets. It is shown that coagulation can give rise to the growth of droplet radius from 5-10 μm up to 30-40 μm for a 10 4 s period f time, and therefore it can play a considerable role in the development of aerosols with droplet radius up to 20 μm when gravitational coagulation is insignificant

Single-particle characterization of urban aerosol particles collected in three Korean cites using low-Z electron probe X-ray microanalysis.

Science.gov (United States)

Ro, Chul-Un; Kim, HyeKyeong; Oh, Keun-Young; Yea, Sun Kyung; Lee, Chong Bum; Jang, Meongdo; Van Grieken, René

2002-11-15

A recently developed single-particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA), was applied to characterize urban aerosol particles collected in three cities of Korea (Seoul, CheongJu, and ChunCheon) on single days in the winter of 1999. In this study, it is clearly demonstrated that the low-Z EPMA technique can provide detailed and quantitative information on the chemical composition of particles in the urban atmosphere. The collected aerosol particles were analyzed and classified on the basis of their chemical species. Various types of particles were identified, such as soil-derived, carbonaceous, marine-originated, and anthropogenic particles. In the sample collected in Seoul, carbonaceous, aluminosilicates, silicon dioxide, and calcium carbonate aerosol particles were abundantly encountered. In the CheongJu and ChunCheon samples, carbonaceous, aluminosilicates, reacted sea salts, and ammonium sulfate aerosol particles were often seen. However, in the CheongJu sample, ammonium sulfate particles were the most abundant in the fine fraction. Also, calcium sulfate and nitrate particles were significantly observed. In the ChunCheon sample, organic particles were the most abundant in the fine fraction. Also, sodium nitrate particles were seen at high levels. The ChunCheon sample seemed to be strongly influenced by sea-salt aerosols originating from the Yellow Sea, which is located about 115 km away from the city.

Wintertime water-soluble aerosol composition and particle water content in Fresno, California

Science.gov (United States)

Parworth, Caroline L.; Young, Dominique E.; Kim, Hwajin; Zhang, Xiaolu; Cappa, Christopher D.; Collier, Sonya; Zhang, Qi

2017-03-01

The composition and concentrations of water-soluble gases and ionic aerosol components were measured from January to February 2013 in Fresno, CA, with a particle-into-liquid sampler with ion chromatography and annular denuders. The average (±1σ) ionic aerosol mass concentration was 15.0 (±9.4) µg m-3, and dominated by nitrate (61%), followed by ammonium, sulfate, chloride, potassium, nitrite, and sodium. Aerosol-phase organic acids, including formate and glycolate, and amines including methylaminium, triethanolaminium, ethanolaminium, dimethylaminium, and ethylaminium were also detected. Although the dominant species all came from secondary aerosol formation, there were primary sources of ionic aerosols as well, including biomass burning for potassium and glycolate, sea spray for sodium, chloride, and dimethylamine, and vehicles for formate. Particulate methanesulfonic acid was also detected and mainly associated with terrestrial sources. On average, the molar concentration of ammonia was 49 times greater than nitric acid, indicating that ammonium nitrate formation was limited by nitric acid availability. Particle water was calculated based on the Extended Aerosol Inorganics Model (E-AIM) thermodynamic prediction of inorganic particle water and κ-Köhler theory approximation of organic particle water. The average (±1σ) particle water concentration was 19.2 (±18.6) µg m-3, of which 90% was attributed to inorganic species. The fractional contribution of particle water to total fine particle mass averaged at 36% during this study and was greatest during early morning and night and least during the day. Based on aqueous-phase concentrations of ions calculated by using E-AIM, the average (±1σ) pH of particles in Fresno during the winter was estimated to be 4.2 (±0.2).

Ultrasonic-resonator-combined apparatus for purifying nuclear aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Hou, Suxia; Zhang, Quanhu; Li, Sufen; Chen, Chen; Su, Xianghua [Xi' an Hi-Tech Institute, Xi' an (China)

2017-12-15

The radiation hazards of radionuclides in the air arising from the storage room of nuclear devices to the operators cannot be ignored. A new ultrasonic-resonator-combined method for purifying nuclear aerosol particles is introduced. To remove particles with diameters smaller than 0.3 μm, an ultrasonic chamber is induced to agglomerate these submicron particles. An apparatus which is used to purify the nuclear aerosol particles is described in the article. The apparatus consists of four main parts: two filtering systems, an ultrasonic chamber and a high-pressure electrostatic precipitator system. Finally, experimental results demonstrated the effectiveness of the implementation of the ultrasonic resonators. The feasibility of the method is proven by its application to the data analysis of the experiments.

Long-term Chemical Characterization of Submicron Aerosol Particles in the Amazon Forest - ATTO Station

Science.gov (United States)

Carbone, S.; Brito, J.; Rizzo, L. V.; Holanda, B. A.; Cirino, G. G.; Saturno, J.; Krüger, M. L.; Pöhlker, C.; Ng, N. L.; Xu, L.; Andreae, M. O.; Artaxo, P.

2015-12-01

The study of the chemical composition of aerosol particles in the Amazon forest represents a step forward to understand the strong coupling between the atmosphere and the forest. For this reason submicron aerosol particles were investigated in the Amazon forest, where biogenic and anthropogenic aerosol particles coexist at the different seasons (wet/dry). The measurements were performed at the ATTO station, which is located about 150 km northeast of Manaus. At ATTO station the Aerosol chemical speciation monitor (ACSM, Aerodyne) and the Multiangle absorption photometer (MAAP, Thermo 5012) have been operated continuously from March 2014 to July 2015. In this study, long-term measurements (near-real-time, ~30 minutes) of PM1 chemical composition were investigated for the first time in this environment.The wet season presented lower concentrations than the dry season (~5 times). In terms of chemical composition, both seasons were dominated by organics (75 and 63%) followed by sulfate (11 and 13%). Nitrate presented different ratio values between the mass-to-charges 30 to 46 (main nitrate fragments) suggesting the presence of nitrate as inorganic and organic nitrate during both seasons. The results indicated that about 75% of the nitrate signal was from organic nitrate during the dry season. In addition, several episodes with elevated amount of chloride, likely in the form of sea-salt from the Atlantic Ocean, were observed during the wet season. During those episodes, chloride comprised up to 7% of the PM1. During the dry season, chloride was also observed; however, with different volatility, which suggested that Chloride was present in different form and source. Moreover, the constant presence of sulfate and BC during the wet season might be related to biomass burning emissions from Africa. BC concentration was 2.5 times higher during the dry season. Further characterization of the organic fraction was accomplished with the positive matrix factorization (PMF), which

Bounce behavior of freshly nucleated biogenic secondary organic aerosol particles

Directory of Open Access Journals (Sweden)

A. Virtanen

2011-08-01

Full Text Available The assessment of the climatic impacts and adverse health effects of atmospheric aerosol particles requires detailed information on particle properties. However, very limited information is available on the morphology and phase state of secondary organic aerosol (SOA particles. The physical state of particles greatly affects particulate-phase chemical reactions, and thus the growth rates of newly formed atmospheric aerosol. Thus verifying the physical phase state of SOA particles gives new and important insight into their formation, subsequent growth, and consequently potential atmospheric impacts. According to our recent study, biogenic SOA particles produced in laboratory chambers from the oxidation of real plant emissions as well as in ambient boreal forest atmospheres can exist in a solid phase in size range >30 nm. In this paper, we extend previously published results to diameters in the range of 17–30 nm. The physical phase of the particles is studied by investigating particle bounce properties utilizing electrical low pressure impactor (ELPI. We also investigate the effect of estimates of particle density on the interpretation of our bounce observations. According to the results presented in this paper, particle bounce clearly decreases with decreasing particle size in sub 30 nm size range. The comparison measurements by ammonium sulphate and investigation of the particle impaction velocities strongly suggest that the decreasing bounce is caused by the differences in composition and phase of large (diameters greater than 30 nm and smaller (diameters between 17 and 30 nm particles.

Source apportionment of aerosol particles using polycapillary slightly focusing X-ray lens

Energy Technology Data Exchange (ETDEWEB)

Sun Tianxi [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: stxbeijing@163.com; Liu Zhiguo [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: liuzgbeijing@163.com; Zhu Guanghua; Liu Hui [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Xu Qing [Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039 (China); Li Yude; Wang Guangpu; Luo Ping; Pan Qiuli; Ding Xunliang [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2009-06-11

A micro-X-ray fluorescence (Micro-XRF) spectrometer based on a polycapillary slightly focusing X-ray lens (PSFXRL) and laboratory X-ray source was designed to carry out the source apportionment of aerosol particles. In the distribution curve of the X-ray intensity in the focal spot of PSFXRL, there was a plateau with a diameter of about 65 {mu}m. The uniformity of this plateau was about 3%. This was helpful in measuring the XRF spectrum of a single aerosol particle in which the element distributions are not uniform. The minimum detection limit (MDL) of this Micro-XRF spectrometer was 15 ppm for the Fe-K{sub {alpha}}. The origins of the aerosol particles at the exit of a subway station and a construction site were apportioned. This Micro-XRF spectrometer has potential applications in analysis of single aerosol particles.

Deposition of aerosol particles in bent pipe

International Nuclear Information System (INIS)

Matsui, Hiroshi; Ohhata, Tsutomu

1989-01-01

An equation to estimate deposition fraction of aerosol particles in a bent pipe is derived and the validity is verified experimentally. The equation is obtained by assuming that the resultant acceleration of the gravity and the centrifugal force induced in the bend acts on the aerosol particles, and is found to give a relatively accurate estimation of the deposition fraction if a certain correction factor is introduced to the equation. The deposition fraction has a minimum against Reynold number, and the deposition due to centrifugal force dominates at greater Reynolds number than that at the minimum deposition fraction. On the other hand, the smaller the radius of curvature of the bend is, the larger the deposition fraction due to the centrifugal force is. (author)

Charged particle traps II applications

CERN Document Server

Werth, Günther; Major, Fouad G

2009-01-01

This, the second volume of Charged Particle Traps, is devoted to applications, complementing the first volume’s comprehensive treatment of the theory and practice of charged particle traps, their many variants and refinements. In recent years, applications of far reaching importance have emerged ranging from the ultra-precise mass determinations of elementary particles and their antiparticles and short-lived isotopes, to high-resolution Zeeman spectroscopy on multiply-charged ions, to microwave and optical spectroscopy, some involving "forbidden" transitions from metastable states of such high resolution that optical frequency standards are realized by locking lasers to them. Further the potential application of trapped ions to quantum computing is explored, based on the extraordinary quantum state coherence made possible by the particle isolation. Consideration is given to the Paul and Penning traps as potential quantum information processors.

Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

Science.gov (United States)

Metcalf, A. R.; Dutcher, C. S.

2014-12-01

Secondary organic aerosol (SOA) particles are nearly ubiquitous in the atmosphere and yet there remains large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. These aerosol interfaces can profoundly affect the fate of condensable organic compounds emitted into the atmosphere by altering the way in which organic vapors interact with the ambient aerosol. Aerosol interfaces affect particle internal structure, species uptake, equilibrium partitioning, activation to cloud condensation or ice nuclei, and optical properties. For example, organic thin films can shield the core of the aerosol from the ambient environment, which may disrupt equilibrium partitioning and mass transfer. To improve our ability to accurately predict the fate of SOA in the atmosphere, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Few technologies exist to accurately probe aerosol interfaces at atmospherically-relevant conditions. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred. Chemical compositions of the liquid phases studied here span a range of viscosities and include electrolyte and water soluble organic acid species often observed in the atmosphere, such as mixtures

Sectional modeling of nanoparticle size and charge distributions in dusty plasmas

International Nuclear Information System (INIS)

Agarwal, Pulkit; Girshick, Steven L

2012-01-01

Sectional models of the dynamics of aerosol populations are well established in the aerosol literature but have received relatively less attention in numerical models of dusty plasmas, where most modeling studies have assumed the existence of monodisperse dust particles. In the case of plasmas in which nanoparticles nucleate and grow, significant polydispersity can exist in particle size distributions, and stochastic charging can cause particles of given size to have a broad distribution of charge states. Sectional models, while computationally expensive, are well suited to treating such distributions. This paper presents an overview of sectional modeling of nanodusty plasmas, and presents examples of simulation results that reveal important qualitative features of the spatiotemporal evolution of such plasmas, many of which could not be revealed by models that consider only monodisperse dust particles and average particle charge. These features include the emergence of bimodal particle populations consisting of very small neutral particles and larger negatively charged particles, the effects of size and charge distributions on coagulation, spreading and structure of the particle cloud, and the dynamics of dusty plasma afterglows. (paper)

Aerosol particle size distribution in the stratosphere retrieved from SCIAMACHY limb measurements

Science.gov (United States)

Malinina, Elizaveta; Rozanov, Alexei; Rozanov, Vladimir; Liebing, Patricia; Bovensmann, Heinrich; Burrows, John P.

2018-04-01

health, stratospheric aerosol plays an important role in atmospheric chemistry and climate change. In particular, information about the amount and distribution of stratospheric aerosols is required to initialize climate models, as well as validate aerosol microphysics models and investigate geoengineering. In addition, good knowledge of stratospheric aerosol loading is needed to increase the retrieval accuracy of key trace gases (e.g. ozone or water vapour) when interpreting remote sensing measurements of the scattered solar light. The most commonly used characteristics to describe stratospheric aerosols are the aerosol extinction coefficient and Ångström coefficient. However, the use of particle size distribution parameters along with the aerosol number density is a more optimal approach. In this paper we present a new retrieval algorithm to obtain the particle size distribution of stratospheric aerosol from space-borne observations of the scattered solar light in the limb-viewing geometry. While the mode radius and width of the aerosol particle size distribution are retrieved, the aerosol particle number density profile remains unchanged. The latter is justified by a lower sensitivity of the limb-scattering measurements to changes in this parameter. To our knowledge this is the first data set providing two parameters of the particle size distribution of stratospheric aerosol from space-borne measurements of scattered solar light. Typically, the mode radius and w can be retrieved with an uncertainty of less than 20 %. The algorithm was successfully applied to the tropical region (20° N-20° S) for 10 years (2002-2012) of SCIAMACHY observations in limb-viewing geometry, establishing a unique data set. Analysis of this new climatology for the particle size distribution parameters showed clear increases in the mode radius after the tropical volcanic eruptions, whereas no distinct behaviour of the absolute distribution width could be identified. A tape recorder

Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

Energy Technology Data Exchange (ETDEWEB)

Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

2016-09-15

Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

Elucidating determinants of aerosol composition through particle-type-based receptor modeling

Science.gov (United States)

McGuire, M. L.; Jeong, C.-H.; Slowik, J. G.; Chang, R. Y.-W.; Corbin, J. C.; Lu, G.; Mihele, C.; Rehbein, P. J. G.; Sills, D. M. L.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

2011-08-01

An aerosol time-of-flight mass spectrometer (ATOFMS) was deployed at a semi-rural site in southern Ontario to characterize the size and chemical composition of individual particles. Particle-type-based receptor modelling of these data was used to investigate the determinants of aerosol chemical composition in this region. Individual particles were classified into particle-types and positive matrix factorization (PMF) was applied to their temporal trends to separate and cross-apportion particle-types to factors. The extent of chemical processing for each factor was assessed by evaluating the internal and external mixing state of the characteristic particle-types. The nine factors identified helped to elucidate the coupled interactions of these determinants. Nitrate-laden dust was found to be the dominant type of locally emitted particles measured by ATOFMS. Several factors associated with aerosol transported to the site from intermediate local-to-regional distances were identified: the Organic factor was associated with a combustion source to the north-west; the ECOC Day factor was characterized by nearby local-to-regional carbonaceous emissions transported from the south-west during the daytime; and the Fireworks factor consisted of pyrotechnic particles from the Detroit region following holiday fireworks displays. Regional aerosol from farther emissions sources was reflected through three factors: two Biomass Burning factors and a highly chemically processed Long Range Transport factor. The Biomass Burning factors were separated by PMF due to differences in chemical processing which were in part elucidated by the passage of two thunderstorm gust fronts with different air mass histories. The remaining two factors, ECOC Night and Nitrate Background, represented the night-time partitioning of nitrate to pre-existing particles of different origins. The distinct meteorological conditions observed during this month-long study in the summer of 2007 provided a unique

Carbonaceous aerosol particles from common vegetation in the Grand Canyon

International Nuclear Information System (INIS)

Hallock, K.A.; Mazurek, M.A.; Cass, G.R.

1992-05-01

The problem of visibility reduction in the Grand Canyon due to fine organic aerosol particles in the atmosphere has become an area of increased environmental concern. Aerosol particles can be derived from many emission sources. In this report, we focus on identifying organic aerosols derived from common vegetation in the Grand Canyon. These aerosols are expected to be significant contributors to the total atmospheric organic aerosol content. Aerosol samples from living vegetation were collected by resuspension of surface wax and resin components liberated from the leaves of vegetation common to areas of the Grand Canyon. The samples were analyzed using high-resolution gas chromatography/mass spectrometry (GC/MS). Probable identification of compounds was made by comparison of sample spectra with National Institute of Standards and Technology (NIST) mass spectral references and positive identification of compounds was made when possible by comparison with authentic standards as well as NIST references. Using these references, we have been able to positively identify the presence of n-alkane and n-alkanoic acid homolog series in the surface waxes of the vegetation sampled. Several monoterpenes, sesquiterpenes, and diterpenes were identified also as possible biogenic aerosols which may contribute to the total organic aerosol abundance leading to visibility reduction in the Grand Canyon

Influence of particle size and chemistry on the cloud nucleating properties of aerosols

Directory of Open Access Journals (Sweden)

P. K. Quinn

2008-02-01

Full Text Available The ability of an aerosol particle to act as a cloud condensation nuclei (CCN is a function of the size of the particle, its composition and mixing state, and the supersaturation of the cloud. In-situ data from field studies provide a means to assess the relative importance of these parameters. During the 2006 Texas Air Quality – Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS, the NOAA RV Ronald H. Brown encountered a wide variety of aerosol types ranging from marine near the Florida panhandle to urban and industrial in the Houston-Galveston area. These varied sources provided an opportunity to investigate the role of aerosol sources and chemistry in the potential activation of particles to form cloud droplets. Measurements were made of CCN concentrations, aerosol chemical composition in the size range relevant for particle activation in warm clouds, and aerosol size distributions. Variability in aerosol composition was parameterized by the mass fraction of Hydrocarbon-like Organic Aerosol (HOA for particle diameters less than 200 nm (vacuum aerodynamic. The HOA mass fraction in this size range was lowest for marine aerosol and highest for aerosol sampled close to anthropogenic sources. Combining all data from the experiment reveals that composition (defined by HOA mass fraction explains 40% of the variance in the critical diameter for particle activation at the instrumental supersaturation (S of 0.44%. Correlations between HOA mass fraction and aerosol mean diameter show that these two parameters are essentially independent of one another for this data set. We conclude that, based on the variability of the HOA mass fraction observed during TexAQS-GoMACCS, variability in particle composition played a significant role in determining the fraction of particles that could activate to form cloud droplets. Using a simple model based on Köhler theory and the assumption that HOA is insoluble, we estimate the

Number concentrations of solid particles from the spinning top aerosol generator

International Nuclear Information System (INIS)

Mitchell, J.P.

1983-02-01

A spinning top aerosol generator has been used to generate monodisperse methylene blue particles in the size range from 0.6 to 6 μm. The number concentrations of these aerosols have been determined by means of an optical particle counter and compared with the equivalent measurements obtained by filter collection and microscopy. (author)

Search milli-charged particles at SLAC

Energy Technology Data Exchange (ETDEWEB)

Langeveld, W.G.J. [Stanford Univ., CA (United States)

1997-01-01

Particles with electric charge q {triple_bond} Qe {le} 10{sup -3} e and masses in the range 1-1000 MeV/c{sup 2} are not excluded by present experiments or by astrophysical or cosmological arguments. A beam dump experiment uniquely suited to the detection of such {open_quotes}milli-charged{close_quotes} particles has been carried out at SLAC, utilizing the short-duration pulses of the SLC electron beam to establish a tight coincidence window for the signal. The detector, a large scintillation counter sensitive to very small energy depositions, provided much greater sensitivity than previous searches. Analysis of the data leads to the exclusion of a substantial portion of the charge-mass plane. In this report, a preliminary mass-dependent upper limit is presented for the charge of milli-charged particles, ranging from Q = 1.7 x 10{sup -5} at milli-charged particle mass 0.1 MeV/c{sup 2} to Q = 9.5 x 10{sup -4} at 100 MeV/c{sup 2}.

The formation of aerosol particles during combustion of biomass and waste. Final report

Energy Technology Data Exchange (ETDEWEB)

Hjerrild Zeuthen, J

2007-05-15

This thesis describes the formation of aerosol particles during combustion of biomass and waste. The formation of aerosol particles is investigated by studying condensation of alkali salts from synthetic flue gasses in a laboratory tubular furnace. In this so-called laminar flow aerosol condenser-furnace gaseous alkali chlorides are mixed with sulphur dioxide, water vapour and oxygen. At high temperatures the alkali chloride reacts with sulphur dioxide to form alkali sulphate. During subsequent cooling of the synthetic flue gas the chlorides and sulphates condense either as deposits on walls or on other particles or directly from the gas phase by homogenous nucleation. A previously developed computer code for simulation of one-component nucleation of particles in a cylindrical laminar flow is extended to include a homogeneous gas phase reaction to produce gaseous alkali sulphate. The formation of aerosol particles during full-scale combustion of wheat straw is investigated in a 100 MW grate-fired boiler. Finally, aerosols from incineration of waste are investigated during full-scale combustion of municipal waste in a 22 MW grate-fired unit. (BA)

Prospects of real-time single-particle biological aerosol analysis: A comparison between laser-induced breakdown spectroscopy and aerosol time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Beddows, D.C.S.; Telle, H.H.

2005-01-01

In this paper we discuss the prospects of real-time, in situ laser-induced breakdown spectroscopy applied for the identification and classification of bio-aerosols (including species of potential bio-hazard) within common urban aerosol mixtures. In particular, we address the issues associated with the picking out of bio-aerosols against common background aerosol particles, comparing laser-induced breakdown spectroscopy measurements with data from a mobile single-particle aerosol mass spectrometer (ATOFMS). The data from the latter provide statistical data over an extended period of time, highlighting the variation of the background composition. While single-particle bio-aerosols are detectable in principle, potential problems with small (∼ 1 μm size) bio-aerosols have been identified; constituents of the air mass other than background aerosols, e.g. gaseous CO 2 in conjunction with common background aerosols, may prevent unique recognition of the bio-particles. We discuss whether it is likely that laser-induced breakdown spectroscopy on its own can provide reliable, real-time identification of bio-aerosol in an urban environment, and it is suggested that more than one technique should be or would have to be used. A case for using a combination of laser-induced breakdown spectroscopy and Raman (and/or) laser-induced fluorescence spectroscopy is made

Charged-particle mutagenesis II. Mutagenic effects of high energy charged particles in normal human fibroblasts

Science.gov (United States)

Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

1994-01-01

The biological effects of high LET charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 micrometer2 and 0.09 to 5.56 x 10(-3) micrometer2, respectively. The maximum values were obtained by 56Fe with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(-5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

Diurnal Cycles of Aerosol Optical Properties at Pico Tres Padres, Mexico City: Evidences for Changes in Particle Morphology and Secondary Aerosol Formation

Science.gov (United States)

Mazzoleni, C.; Dubey, M.; Chakrabarty, R.; Moosmuller, H.; Onasch, T.; Zavala, M.; Herndon, S.; Kolb, C.

2007-12-01

Aerosol optical properties affect planetary radiative balance and depend on chemical composition, size distribution, and morphology. During the MILAGRO field campaign, we measured aerosol absorption and scattering in Mexico City using the Los Alamos aerosol photoacoustic (LAPA) instrument operating at 781 nm. The LAPA was mounted on-board the Aerodyne Research Inc. mobile laboratory, which hosted a variety of gaseous and aerosol instruments. During the campaign, the laboratory was moved to different sites, capturing spatial and temporal variability. Additionally, we collected ambient aerosols on Nuclepore filters for scanning electron microscopy (SEM) analysis. SEM images of selected filters were taken to study particle morphology. Between March 7th and 19th air was sampled at the top of Pico Tres Padres, a mountain on the north side of Mexico City. Aerosol absorption and scattering followed diurnal patterns related to boundary layer height and solar insulation. We report an analysis of aerosol absorption, scattering, and morphology for three days (9th, 11th and 12th of March 2006). The single scattering albedo (SSA, ratio of scattering to total extinction) showed a drop in the tens-of-minutes-to-hour time frame after the boundary layer grew above the sampling site. Later in the day the SSA rose steadily reaching a maximum in the afternoon. The SEM images showed a variety of aerosol shapes including fractal-like aggregates, spherical particles, and other shapes. The absorption correlated with the CO2 signal and qualitatively with the fraction of fractal-like particles to the total particle count. In the afternoon the SSA qualitatively correlated with a relative increase in spherical particles and total particle count. These observed changes in optical properties and morphology can be explained by the dominant contribution of freshly emitted particles in the morning and by secondary particle formation in the afternoon. SSA hourly averaged values ranged from ~0.63 in

Quantum and classical dissipation of charged particles

Energy Technology Data Exchange (ETDEWEB)

Ibarra-Sierra, V.G. [Departamento de Física, Universidad Autónoma Metropolitana at Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 México D.F. (Mexico); Anzaldo-Meneses, A.; Cardoso, J.L.; Hernández-Saldaña, H. [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana at Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico); Kunold, A., E-mail: akb@correo.azc.uam.mx [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana at Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico); Roa-Neri, J.A.E. [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana at Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico)

2013-08-15

A Hamiltonian approach is presented to study the two dimensional motion of damped electric charges in time dependent electromagnetic fields. The classical and the corresponding quantum mechanical problems are solved for particular cases using canonical transformations applied to Hamiltonians for a particle with variable mass. Green’s function is constructed and, from it, the motion of a Gaussian wave packet is studied in detail. -- Highlights: •Hamiltonian of a damped charged particle in time dependent electromagnetic fields. •Exact Green’s function of a charged particle in time dependent electromagnetic fields. •Time evolution of a Gaussian wave packet of a damped charged particle. •Classical and quantum dynamics of a damped electric charge.

Quantum and classical dissipation of charged particles

International Nuclear Information System (INIS)

Ibarra-Sierra, V.G.; Anzaldo-Meneses, A.; Cardoso, J.L.; Hernández-Saldaña, H.; Kunold, A.; Roa-Neri, J.A.E.

2013-01-01

A Hamiltonian approach is presented to study the two dimensional motion of damped electric charges in time dependent electromagnetic fields. The classical and the corresponding quantum mechanical problems are solved for particular cases using canonical transformations applied to Hamiltonians for a particle with variable mass. Green’s function is constructed and, from it, the motion of a Gaussian wave packet is studied in detail. -- Highlights: •Hamiltonian of a damped charged particle in time dependent electromagnetic fields. •Exact Green’s function of a charged particle in time dependent electromagnetic fields. •Time evolution of a Gaussian wave packet of a damped charged particle. •Classical and quantum dynamics of a damped electric charge

On the sources of submicron aerosol particles in savannah: implications for climate and air quality

Energy Technology Data Exchange (ETDEWEB)

Vakkari, V.

2013-11-01

Aerosol is defined as solid or liquid particles suspended in a gas lighter than the particles, which means that the atmosphere we live in is an aerosol in itself. Although aerosol particles are only a trace component of the atmosphere they affect our lives in several ways. The aerosol particles can cause adverse health effects and deteriorate visibility, but they affect also the Earth s climate directly by scattering and absorbing solar radiation and indirectly by modulating the properties of the clouds. Anthropogenic aerosol particles have a net cooling effect on the climate, but the uncertainty in the amount of cooling is presently as large as the heating effect of carbon dioxide. To reduce the uncertainty in the aerosol climate effects, spatially representative reference data of high quality are needed for the global climate models. To be able to capture the diurnal and seasonal variability the data have to be collected continuously over time periods that cover at least one full seasonal cycle. Until recently such data have been nearly non-existing for continental Africa and hence one aim of this work was to establish a permanent measurement station measuring the key aerosol particle properties in a continental location in southern Africa. In close collaboration with the North-West University in South Africa this aim has now been achieved at the Welgegund measurement station. The other aims of this work were to determine the aerosol particle concentrations including their seasonal and diurnal variation and to study the most important aerosol particle sources in continental southern Africa. In this thesis the aerosol size distribution and its seasonal and diurnal variation is reported for different environments ranging from a clean rural background to an anthropogenically heavily influenced mining region in continental southern Africa. Atmospheric regional scale new particle formation has been observed at a world record high frequency and it dominates the diurnal

Papers of the 15. french congress on the aerosols CFA 99

International Nuclear Information System (INIS)

2000-01-01

This french congress on the aerosols took place in Paris the 8 and 9 december 1999. It was presented in four main themes: bio-aerosols and filtering; the aerosols metrology; the aerosols in the environment; aerosols physic and applications. Seven papers have been analyzed in INIS data base for their specific interest in the nuclear industry. They concern the aerosol capture simulation, the aerosols sampling in workplace environment, a ring-effect ion generator development for the charge and the neutralization of an aerosol cloud, the radon 222 characterization in a house, a particle re-entrainment, the electrical charge process of beta emitter radioactive aerosols, the simulation of air flows in many filters. The other ones are analyzed in the ETDE data base. (A.L.B.)

Electronically shielded solid state charged particle detector

International Nuclear Information System (INIS)

Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

1996-01-01

An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig

Interpretation of aerosol trace metal particle size distributions

International Nuclear Information System (INIS)

Johansson, T.B.; Van Grieken, R.E.; Winchester, J.W.

1974-01-01

Proton-induced X-ray emission (PIXE) analysis is capable of rapid routine determination of 10--15 elements present in amounts greater than or equal to 1 ng simultaneously in aerosol size fractions as collected by single orifice impactors over short periods of time. This enables detailed study of complex relationships between elements detected. Since absolute elemental concentrations may be strongly influenced by meteorological and topographical conditions, it is useful to normalize to a reference element. Comparison between the ratios of concentrations with aerosol and corresponding values for anticipated sources may lead to the identification of important sources for the elements. Further geochemical insights may be found through linear correlation coefficients, regression analysis, and cluster analysis. By calculating correlations for elemental pairs, an indication of the degree of covariance between the elements is obtained. Preliminary results indicate that correlations may be particle size dependent. A high degree of covariance may be caused either by a common source or may only reflect the conservative nature of the aerosol. In a regression analysis, by plotting elemental pairs and estimating the regression coefficients, we may be able to conclude if there is more than one source operating for a given element in a certain size range. Analysis of clustering of several elements, previously investigated for aerosol filter samples, can be applied to the analysis of aerosol size fractions. Careful statistical treatment of elemental concentrations as a function of aerosol particle size may thus yield significant information on the generation, transport and deposition of trace metals in the atmosphere

Real-time aerosol photometer and optical particle counter comparison

International Nuclear Information System (INIS)

Santi, E.; Belosi, F.; Santachiara, G.; Prodi, F.; Berico, M.

2010-01-01

The paper presents the results of a comparison exercise among real-time aerosol samplers, based on different light scattering techniques. The comparison was carried out near to the ISAC institute in a box positioned inside the CNR research area in Bologna. Two nephelometers (Dust Trak from TSI, and Air Genius from Unitec) and an optical particle counter (ENVIRO-check from Grimm) were used for P M1 and P M10 fraction assessment. In the case of the optical particle counter, the particle number concentration in each size bin was also used. In parallel, two manual sampling lines were employed for reference (gravimetric) measurements. The results highlight different factor scales for the dust monitors, in comparison with gravimetric assessment, underlining the importance of a user calibration of such monitors as a function of the specific aerosol sampled. Moreover, the relative fluctuations of the hourly P M 10 and P M1 concentrations, against daily average concentrations, were studied in order to compare the ability of each sampler to follow changes in the aerosol size distribution. It was found that the photometers and optical particle counter revealed different behaviours. In the latter, a small increase in the particle concentration number in the coarse fraction gave a relatively high increase in the mass concentration that was not measured by the photometers. The explanation could be the relatively slight influence of a small particle number variation on the total scattered light for the photometers, unlike the case of the optical particle counter, where each particle contributes to the mass concentration. This aspect merits future research in order to better understand optical particle counter output used in P Mx monitoring activities.

Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Goldmann, Maximilian; Miguel-Sánchez, Javier; West, Adam H. C.; Yoder, Bruce L.; Signorell, Ruth, E-mail: rsignorell@ethz.ch [Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland)

2015-06-14

We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. First, aerosol photoemission studies can be performed for many different materials, including liquids. Second, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.

Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles

Directory of Open Access Journals (Sweden)

T. Furukawa

2011-05-01

Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the

Particle size of radioactive aerosols generated during machine operation in high-energy proton accelerators

International Nuclear Information System (INIS)

Oki, Yuichi; Kanda, Yukio; Kondo, Kenjiro; Endo, Akira

2000-01-01

In high-energy accelerators, non-radioactive aerosols are abundantly generated due to high radiation doses during machine operation. Under such a condition, radioactive atoms, which are produced through various nuclear reactions in the air of accelerator tunnels, form radioactive aerosols. These aerosols might be inhaled by workers who enter the tunnel just after the beam stop. Their particle size is very important information for estimation of internal exposure doses. In this work, focusing on typical radionuclides such as 7 Be and 24 Na, their particle size distributions are studied. An aluminum chamber was placed in the EP2 beam line of the 12-GeV proton synchrotron at High Energy Accelerator Research Organization (KEK). Aerosol-free air was introduced to the chamber, and aerosols formed in the chamber were sampled during machine operation. A screen-type diffusion battery was employed in the aerosol-size analysis. Assuming that the aerosols have log-normal size distributions, their size distributions were obtained from the radioactivity concentrations at the entrance and exit of the diffusion battery. Radioactivity of the aerosols was measured with Ge detector system, and concentrations of non-radioactive aerosols were obtained using condensation particle counter (CPC). The aerosol size (radius) for 7 Be and 24 Na was found to be 0.01-0.04 μm, and was always larger than that for non-radioactive aerosols. The concentration of non-radioactive aerosols was found to be 10 6 - 10 7 particles/cm 3 . The size for radioactive aerosols was much smaller than ordinary atmospheric aerosols. Internal doses due to inhalation of the radioactive aerosols were estimated, based on the respiratory tract model of ICRP Pub. 66. (author)

Comparison of diffusion charging and mobility-based methods for measurement of aerosol agglomerate surface area.

Science.gov (United States)

Ku, Bon Ki; Kulkarni, Pramod

2012-05-01

We compare different approaches to measure surface area of aerosol agglomerates. The objective was to compare field methods, such as mobility and diffusion charging based approaches, with laboratory approach, such as Brunauer, Emmett, Teller (BET) method used for bulk powder samples. To allow intercomparison of various surface area measurements, we defined 'geometric surface area' of agglomerates (assuming agglomerates are made up of ideal spheres), and compared various surface area measurements to the geometric surface area. Four different approaches for measuring surface area of agglomerate particles in the size range of 60-350 nm were compared using (i) diffusion charging-based sensors from three different manufacturers, (ii) mobility diameter of an agglomerate, (iii) mobility diameter of an agglomerate assuming a linear chain morphology with uniform primary particle size, and (iv) surface area estimation based on tandem mobility-mass measurement and microscopy. Our results indicate that the tandem mobility-mass measurement, which can be applied directly to airborne particles unlike the BET method, agrees well with the BET method. It was also shown that the three diffusion charging-based surface area measurements of silver agglomerates were similar within a factor of 2 and were lower than those obtained from the tandem mobility-mass and microscopy method by a factor of 3-10 in the size range studied. Surface area estimated using the mobility diameter depended on the structure or morphology of the agglomerate with significant underestimation at high fractal dimensions approaching 3.

Improved identification of primary biological aerosol particles using single-particle mass spectrometry

Directory of Open Access Journals (Sweden)

M. A. Zawadowicz

2017-06-01

Full Text Available Measurements of primary biological aerosol particles (PBAP, especially at altitudes relevant to cloud formation, are scarce. Single-particle mass spectrometry (SPMS has been used to probe aerosol chemical composition from ground and aircraft for over 20 years. Here we develop a method for identifying bioaerosols (PBAP and particles containing fragments of PBAP as part of an internal mixture using SPMS. We show that identification of bioaerosol using SPMS is complicated because phosphorus-bearing mineral dust and phosphorus-rich combustion by-products such as fly ash produce mass spectra with peaks similar to those typically used as markers for bioaerosol. We have developed a methodology to differentiate and identify bioaerosol using machine learning statistical techniques applied to mass spectra of known particle types. This improved method provides far fewer false positives compared to approaches reported in the literature. The new method was then applied to two sets of ambient data collected at Storm Peak Laboratory and a forested site in Central Valley, California to show that 0.04–2 % of particles in the 200–3000 nm aerodynamic diameter range were identified as bioaerosol. In addition, 36–56 % of particles identified as biological also contained spectral features consistent with mineral dust, suggesting internal dust–biological mixtures.

Spatial Variability of CCN Sized Aerosol Particles

Science.gov (United States)

Asmi, A.; Väänänen, R.

2014-12-01

The computational limitations restrict the grid size used in GCM models, and for many cloud types they are too large when compared to the scale of the cloud formation processes. Several parameterizations for e.g. convective cloud formation exist, but information on spatial subgrid variation of the cloud condensation nuclei (CCNs) sized aerosol concentration is not known. We quantify this variation as a function of the spatial scale by using datasets from airborne aerosol measurement campaigns around the world including EUCAARI LONGREX, ATAR, INCA, INDOEX, CLAIRE, PEGASOS and several regional airborne campaigns in Finland. The typical shapes of the distributions are analyzed. When possible, we use information obtained by CCN counters. In some other cases, we use particle size distribution measured by for example SMPS to get approximated CCN concentration. Other instruments used include optical particle counters or condensational particle counters. When using the GCM models, the CCN concentration used for each the grid-box is often considered to be either flat, or as an arithmetic mean of the concentration inside the grid-box. However, the aircraft data shows that the concentration values are often lognormal distributed. This, combined with the subgrid variations in the land use and atmospheric properties, might cause that the aerosol-cloud interactions calculated by using mean values to vary significantly from the true effects both temporary and spatially. This, in turn, can cause non-linear bias into the GCMs. We calculate the CCN aerosol concentration distribution as a function of different spatial scales. The measurements allow us to study the variation of these distributions within from hundreds of meters up to hundreds of kilometers. This is used to quantify the potential error when mean values are used in GCMs.

Characterization of aerosol particles from grass mowing by joint deployment of ToF-AMS and ATOFMS instruments

Science.gov (United States)

Drewnick, Frank; Dall'Osto, Manuel; Harrison, Roy

During a measurement campaign at a semi-urban/industrial site a grass-cutting event was observed, when the lawn in the immediate surrounding of the measurement site was mowed. Using a wide variety of state-of-the-art aerosol measurement technology allowed a broad characterization of the aerosol generated by the lawn mowing. The instrumentation included two on-line aerosol mass spectrometers: an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (ToF-AMS) and a TSI Aerosol Time-of-Flight Mass Spectrometer (ATOFMS); in addition, a selection of on-line aerosol concentration and size distribution instruments (OPC, APS, SMPS, CPC, FDMS-TEOM, MAAP) was deployed. From comparison of background aerosol measurements during most of the day with the aerosol measured during the lawn mowing, the grass cutting was found to generate mainly two different types of aerosol particles: an intense ultrafine particle mode (1 h average: 4 μg m -3) of almost pure hydrocarbon-like organics and a distinct particle mode in the upper sub-micrometer size range containing particles with potassium and nitrogen-organic compounds. The ultrafine particles are probably lubricating oil particles from the lawn mower exhaust; the larger particles are swirled-up plant debris particles from the mowing process. While these particle types were identified in the data from the two mass spectrometers, the on-line aerosol concentration and size distribution data support these findings. The results presented here show that the combination of quantitative aerosol particle ensemble mass spectrometry (ToF-AMS) and single particle mass spectrometry (ATOFMS) provides much deeper insights into the nature of the aerosol properties than each of the instruments could do alone. Therefore a combined deployment of both types of instruments is strongly recommended.

Charged-particle mutagenesis 2. Mutagenic effects of high energy charged particles in normal human fibroblasts

Science.gov (United States)

Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

1994-01-01

The biological effects of high Linear Energy Transfer (LET) charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 sq micrometer and 0.09 to 5.56 x 10(exp -3) sq micrometer respectively. The maximum values were obtained by Fe-56 with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(exp -5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

Development of a 10 Hz measurement system for atmospheric aerosol concentration

International Nuclear Information System (INIS)

Bouarouri, Assia

2014-01-01

The goal is to develop an aerosol charger based on a corona discharge for atmospheric concentration measurements (10 3 -10 5 cm -3 ) within a response time of 100 ms. Two ion sources, point-to-hole and wire-to-slit have been characterized. The increase of the ion flow in the post-discharge by EHD ion confinement in both the discharge gap and the hole has been shown. At first, using an experimental survey driven in two mixing configurations, concentric and face-to-face, we have confirmed the aerosol diffusion charging law which depends on aerosol diameter and N i .t product, with N i , the ions concentration and t, the charging time. Thus, the originality of this charger relies on the very high heterogeneity of unipolar ion densities (N i 0 ≥10 9 cm -3 ) required to compensate the charging time of 50 ms. In these conditions, we have shown that aerosol diameter and the charging dynamic (which depends also on the diameter) control the aerosol trajectory. The chargers have, next, been compared in different operating conditions, mainly in terms of the maximal charging and the minimal losses. In the chosen charger (point-to-hole ion source and concentric mixing), the relations charge/mobility and losses according to diameter have been characterized. We have also shown the linearity of the charged particles current with the aerosol concentration which allows the current-concentration data inversion. The preliminary measurement system composed by the charger, the separator and the particle current measurements, satisfies the objectives of the study in terms of the concentration detection limit (10 3 cm -3 ) and the response time (100 ms). We have thus shown the feasibility of an atmospheric aerosol concentration measurement system at 10 Hz using a corona discharge charger provided that the separation power is improved. Furthermore, knowing that aerosol losses are negligible and the lower limit of the partial charging, the developed charger is adaptable with other

AEROSOL PARTICLE COLLECTOR DESIGN STUDY

Energy Technology Data Exchange (ETDEWEB)

Lee, S; Richard Dimenna, R

2007-09-27

A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

Inside versus Outside: Ion Redistribution in Nitric Acid Reacted Sea Spray Aerosol Particles as Determined by Single Particle Analysis (Invited)

Science.gov (United States)

Ault, A. P.; Guasco, T.; Ryder, O. S.; Baltrusaitis, J.; Cuadra-Rodriguez, L. A.; Collins, D. B.; Ruppel, M. J.; Bertram, T. H.; Prather, K. A.; Grassian, V. H.

2013-12-01

Sea spray aerosol (SSA) particles were generated under real-world conditions using natural seawater and a unique ocean-atmosphere facility equipped with actual breaking waves or a marine aerosol reference tank (MART) that replicates those conditions. The SSA particles were exposed to nitric acid in situ in a flow tube and the well-known chloride displacement and nitrate formation reaction was observed. However, as discussed here, little is known about how this anion displacement reaction affects the distribution of cations and other chemical constituents within and phase state of individual SSA particles. Single particle analysis of individual SSA particles shows that cations (Na+, K+, Mg2+ and Ca2+) within individual particles undergo a spatial redistribution after heterogeneous reaction with nitric acid, along with a more concentrated layer of organic matter at the surface of the particle. These data suggest that specific ion and aerosol pH effects play an important role in aerosol particle structure in ways that have not been previously recognized. The ordering of organic coatings can impact trace gas uptake, and subsequently impact trace gas budgets of O3 and NOx.

Discharge current measurements on Venera 13 & 14 - Evidence for charged aerosols in the Venus lower atmosphere?

Science.gov (United States)

Lorenz, Ralph D.

2018-06-01

Measurements of discharge currents on the Venera 13 and 14 landers during their descent in the lowest 35 km of the Venus atmosphere are interpreted as driven either by an ambient electric field, or by deposition of charge from aerosols. The latter hypothesis is favored (`triboelectric charging' in aeronautical parlance), and would entail an aerosol opacity and charge density somewhat higher than that observed in Saharan dust transported over long distances on Earth.

Wintertime hygroscopicity and volatility of ambient urban aerosol particles

Science.gov (United States)

Enroth, Joonas; Mikkilä, Jyri; Németh, Zoltán; Kulmala, Markku; Salma, Imre

2018-04-01

Hygroscopic and volatile properties of atmospheric aerosol particles with dry diameters of (20), 50, 75, 110 and 145 nm were determined in situ by using a volatility-hygroscopicity tandem differential mobility analyser (VH-TDMA) system with a relative humidity of 90 % and denuding temperature of 270 °C in central Budapest during 2 months in winter 2014-2015. The probability density function of the hygroscopic growth factor (HGF) showed a distinct bimodal distribution. One of the modes was characterised by an overall mean HGF of approximately 1.07 (this corresponds to a hygroscopicity parameter κ of 0.033) independently of the particle size and was assigned to nearly hydrophobic (NH) particles. Its mean particle number fraction was large, and it decreased monotonically from 69 to 41 % with particle diameter. The other mode showed a mean HGF increasing slightly from 1.31 to 1.38 (κ values from 0.186 to 0.196) with particle diameter, and it was attributed to less hygroscopic (LH) particles. The mode with more hygroscopic particles was not identified. The probability density function of the volatility GF (VGF) also exhibited a distinct bimodal distribution with an overall mean VGF of approximately 0.96 independently of the particle size, and with another mean VGF increasing from 0.49 to 0.55 with particle diameter. The two modes were associated with less volatile (LV) and volatile (V) particles. The mean particle number fraction for the LV mode decreased from 34 to 21 % with particle diameter. The bimodal distributions indicated that the urban atmospheric aerosol contained an external mixture of particles with a diverse chemical composition. Particles corresponding to the NH and LV modes were assigned mainly to freshly emitted combustion particles, more specifically to vehicle emissions consisting of large mass fractions of soot likely coated with or containing some water-insoluble organic compounds such as non-hygroscopic hydrocarbon-like organics. The hygroscopic

Measurements of phoretic velocities of aerosol particles in microgravity conditions

Science.gov (United States)

Prodi, F.; Santachiara, G.; Travaini, S.; Vedernikov, A.; Dubois, F.; Minetti, C.; Legros, J. C.

2006-11-01

Measurements of thermo- and diffusio-phoretic velocities of aerosol particles (carnauba wax, paraffin and sodium chloride) were performed in microgravity conditions (Drop Tower facility, in Bremen, and Parabolic Flights, in Bordeaux). In the case of thermophoresis, a temperature gradient was obtained by heating the upper plate of the cell, while the lower one was maintained at environmental temperature. For diffusiophoresis, the water vapour gradient was obtained with sintered plates imbued with a water solution of MgCl 2 and distilled water, at the top and at the bottom of the cell, respectively. Aerosol particles were observed through a digital holographic velocimeter, a device allowing the determination of 3-D coordinates of particles from the observed volume. Particle trajectories and consequently particle velocities were reconstructed through the analysis of the sequence of particle positions. The experimental values of reduced thermophoretic velocities are between the theoretical values of Yamamoto and Ishihara [Yamamoto, K., Ishihara, Y., 1988. Thermophoresis of a spherical particle in a rarefied gas of a transition regime. Phys. Fluids. 31, 3618-3624] and Talbot et al. [Talbot, L., Cheng, R.K., Schefer, R.W., Willis, D.R., 1980. Thermophoresis of particles in a heated boundary layer. J. Fluid Mech. 101, 737-758], and do not show a clear dependence on the thermal conductivity of the aerosol. The existence of negative thermophoresis is not confirmed in our experiments. Concerning diffusiophoretic experiments, the results obtained show a small increase of reduced diffusiophoretic velocity with the Knudsen number.

Aerosol vertical distribution, new particle formation, and jet aircraft particle emissions in the free troposhere and tropopause region; Vertikalverteilung und Neubildungsprozesse des Aerosols und partikelfoermige Flugzeugemissionen in der freien Troposphaere und Tropopausenregion

Energy Technology Data Exchange (ETDEWEB)

Schroeder, F P

2000-07-01

A contribution to the understanding of natural and anthropogenously induced particle formation as well as aerosol physical transformation processes within the free troposphere (FT) is introduced. Documentation and interpretation of empirical data relevant with respect to possible climatologic impact of anthropogenous aerosol emissions into the atmosphere is presented. The first section describes new technique for high spatial resolution measurements of ultrafine aerosol particles by condensation nucleus counters (CNCs), a necessary prerequisite for the observation of natural particle formation and jet aircraft emissions. The second section illustrates vertical distribution and variability ranges of the aerosol in the FT and the tropopause region (TP). Typical microphysical states of the atmospheric aerosol within the Northern Hemisphere are documented by means of systematic measurements during more than 60 flight missions. Simple mathematical parameterizations of the aerosol vertical distribution and aerosol size distributions are developed. Important aerosol sources within the FT are localized and possible aerosol formation processes are discussed. The third section is focussed on jet-engine particle emissions within the FT and TP. A unique inflight experiment for detection of extremely high concentrations (>10{sup 6} cm{sup -3}) of extremely small (donw to <3 nm) aerosols inside the exhaust plumes of several jet aircraft is described. Particle emission indices and emission-controlling parameters are deduced. Most important topic is the impact of fuel sulfur content of kerosine on number, size and chemical composition of jet particle emissions. Generalized results are parameterized in form of lognormal aerosol particle size distributions. (orig.) [German] Ein Beitrag zum Verstaendnis natuerlicher und anthropogen induzierter Aerosolneubildung sowie physikalischer Aerosolumwandlung in der freien Troposphaere wird vorgestellt. Empirisch gewonnenes Datenmaterial wird

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation

Science.gov (United States)

Shiraiwa, Manabu; Yee, Lindsay D.; Schilling, Katherine A.; Loza, Christine L.; Craven, Jill S.; Zuend, Andreas; Ziemann, Paul J.; Seinfeld, John H.

2013-01-01

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process. PMID:23818634

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

Science.gov (United States)

Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

2013-07-16

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

Proposal to Search for Magnetically Charged Particles with Magnetic Charge 1e

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Michael K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fryberger, David [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2015-11-02

A model for composite elementary Standard Model (SM) particles based upon magnetically bound vorton pairs, we briefly introduce here, predicts the existence of a complete family of magnetically charged particles, as well as their neutral isotopic partners (all counterparts to the SM elementary particles), in which the lowest mass (charged) particle would be an electrically neutral stable lepton, but which carries a magnetic charge equivalent to 1e. This new particle, which we call a magneticon (a counterpart to the electron) would be pair produced at all e⁺e^- colliders at an E_cm above twice its mass. In addition, PP and PPbar colliders should also be able to produce these new particles through the Drell-Yan process. To our knowledge, no monopole search experiment has been sensitive to such a low-charged magnetic monopole above a particle mass of about 5 GeV/c². Hence, we propose that a search for such a stable particle of magnetic charge 1e should be undertaken. We have taken the ATLAS detector at the LHC as an example in which this search might be done. To this end, we modeled the magnetic fields and muon trigger chambers of this detector. We show results from a simple Monte Carlo simulation program to indicate how these particles might look in the detector and describe how one might search for these new particles in the ATLAS data stream.

Particle size distribution of aerosols sprayed from household hand-pump sprays containing fluorine-based and silicone-based compounds.

Science.gov (United States)

Kawakami, Tsuyoshi; Isama, Kazuo; Ikarashi, Yoshiaki

2015-01-01

Japan has published safety guideline on waterproof aerosol sprays. Furthermore, the Aerosol Industry Association of Japan has adopted voluntary regulations on waterproof aerosol sprays. Aerosol particles of diameter less than 10 µm are considered as "fine particles". In order to avoid acute lung injury, this size fraction should account for less than 0.6% of the sprayed aerosol particles. In contrast, the particle size distribution of aerosols released by hand-pump sprays containing fluorine-based or silicone-based compounds have not been investigated in Japan. Thus, the present study investigated the aerosol particle size distribution of 16 household hand-pump sprays. In 4 samples, the ratio of fine particles in aerosols exceeded 0.6%. This study confirmed that several hand-pump sprays available in the Japanese market can spray fine particles. Since the hand-pump sprays use water as a solvent and their ingredients may be more hydrophilic than those of aerosol sprays, the concepts related to the safety of aerosol-sprays do not apply to the hand pump sprays. Therefore, it may be required for the hand-pump spray to develop a suitable method for evaluating the toxicity and to establish the safety guideline.

On the secondary charging effects and structure of mesospheric dust particles impacting on rocket probes

Energy Technology Data Exchange (ETDEWEB)

Havnes, O.; Naesheim, L.I. [Inst. of Physics, Univ. of Tromso (Norway)

2007-07-01

The dust probe DUSTY, first launched during the summer of 1994 (flights ECT-02 and ECT-07) from Andoeya Rocket Range, northern Norway, was the first probe to unambiguously detect heavy charged mesospheric aerosols, from hereon referred to as dust. In ECT-02 the probe detected negatively charged dust particles in the height interval of 83 to 88.5 km. In this flight, the lower grid in the detector (Grid 2) measures both positive and negative currents in various regions, and we find that the relationship between the current measurements of Grid 2 and the bottom plate can only be explained by influence from secondary charge production on Grid 2. In ECT-07, which had a large coning, positive currents reaching the top grid of the probe were interpreted as due to the impact of positively charged dust particles. We have now reanalyzed the data from ECT-07 and arrived at the conclusion that the measured positive currents to this grid must have been mainly due to secondary charging effects from the impacting dust particles. The grid consists of a set of parallel wires crossed with an identical set of wires on top of it, and we find that if the observed currents were created from the direct impact of charged dust particles, then they should be very weakly modulated at four times the rocket spin rate {omega}{sub R}. Observations show, however, that the observed currents are strongly modulated at 2{omega}{sub R}. We cannot reproduce the observed large modulations of the impact currents in the dust layer if the currents are due only to the transfer of the charges on the impacted dust particles. Based on the results of recent ice cluster impact secondary charging experiments by Tomsic (2003), which found that a small fraction of the ice clusters, when impacting with nearly grazing incidence, carried away one negative charge - 1e, we have arrived at the conclusion that similar, but significantly more effective, charging effects must be predominantly responsible for the positive

Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation

Science.gov (United States)

Gordon, Hamish; Sengupta, Kamalika; Rap, Alexandru; Duplissy, Jonathan; Frege, Carla; Williamson, Christina; Heinritzi, Martin; Simon, Mario; Yan, Chao; Almeida, João; Tröstl, Jasmin; Nieminen, Tuomo; Ortega, Ismael K.; Wagner, Robert; Dunne, Eimear M.; Adamov, Alexey; Amorim, Antonio; Bernhammer, Anne-Kathrin; Bianchi, Federico; Breitenlechner, Martin; Brilke, Sophia; Chen, Xuemeng; Craven, Jill S.; Dias, Antonio; Ehrhart, Sebastian; Fischer, Lukas; Flagan, Richard C.; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Hakala, Jani; Hoyle, Christopher R.; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Molteni, Ugo; Monks, Sarah A.; Onnela, Antti; Peräkylä, Otso; Piel, Felix; Petäjä, Tuukka; Praplan, Arnaud P.; Pringle, Kirsty J.; Richards, Nigel A. D.; Rissanen, Matti P.; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Scott, Catherine E.; Seinfeld, John H.; Sharma, Sangeeta; Sipilä, Mikko; Steiner, Gerhard; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Virtanen, Annele; Vogel, Alexander Lucas; Wagner, Andrea C.; Wagner, Paul E.; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M.; Ye, Penglin; Zhang, Xuan; Hansel, Armin; Dommen, Josef; Donahue, Neil M.; Worsnop, Douglas R.; Baltensperger, Urs; Kulmala, Markku; Curtius, Joachim; Carslaw, Kenneth S.

2016-10-01

The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol-cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20-100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by 0.22 W m-2 (27%) to -0.60 W m-2. Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.

Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation.

Science.gov (United States)

Gordon, Hamish; Sengupta, Kamalika; Rap, Alexandru; Duplissy, Jonathan; Frege, Carla; Williamson, Christina; Heinritzi, Martin; Simon, Mario; Yan, Chao; Almeida, João; Tröstl, Jasmin; Nieminen, Tuomo; Ortega, Ismael K; Wagner, Robert; Dunne, Eimear M; Adamov, Alexey; Amorim, Antonio; Bernhammer, Anne-Kathrin; Bianchi, Federico; Breitenlechner, Martin; Brilke, Sophia; Chen, Xuemeng; Craven, Jill S; Dias, Antonio; Ehrhart, Sebastian; Fischer, Lukas; Flagan, Richard C; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Hakala, Jani; Hoyle, Christopher R; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Molteni, Ugo; Monks, Sarah A; Onnela, Antti; Peräkylä, Otso; Piel, Felix; Petäjä, Tuukka; Praplan, Arnaud P; Pringle, Kirsty J; Richards, Nigel A D; Rissanen, Matti P; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Scott, Catherine E; Seinfeld, John H; Sharma, Sangeeta; Sipilä, Mikko; Steiner, Gerhard; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Virtanen, Annele; Vogel, Alexander Lucas; Wagner, Andrea C; Wagner, Paul E; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Zhang, Xuan; Hansel, Armin; Dommen, Josef; Donahue, Neil M; Worsnop, Douglas R; Baltensperger, Urs; Kulmala, Markku; Curtius, Joachim; Carslaw, Kenneth S

2016-10-25

The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol-cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20-100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by [Formula: see text] (27%) to [Formula: see text] Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.

The physico-chemical evolution of atmospheric aerosols and the gas-particle partitioning of inorganic aerosol during KORUS-AQ

Science.gov (United States)

Lee, T.; Park, T.; Lee, J. B.; Lim, Y. J.; Ahn, J.; Park, J. S.; Soo, C. J.; Desyaterik, Y.; Collett, J. L., Jr.

2017-12-01

Aerosols influence climate change directly by scattering and absorption and indirectly by acting as cloud condensation nuclei and some of the effects of aerosols are reduction in visibility, deterioration of human health, and deposition of pollutants to ecosystems. Urban area is large source of aerosols and aerosol precursors. Aerosol sources are both local and from long-range transport. Long-range transport processed aerosol are often dominant sources of aerosol pollution in Korea. To improve our knowledge of aerosol chemistry, Korea and U.S-Air Quality (KORUS-AQ) of Aircraft-based aerosol measurement took place in and around Seoul, Korea during May and June 2016. KORUS-AQ campaigns were conducted to study the chemical characterization and processes of pollutants in the Seoul Metropolitan area to regional scales of Korean peninsula. Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed on aircraft platforms on-board DC-8 (NASA) aircraft. We characterized aerosol chemical properties and mass concentrations of sulfate, nitrate, ammonium and organics in polluted air plumes and investigate the spatial and vertical distribution of the species. The results of studies show that organics is predominant in Aerosol and a significant fraction of the organics is oxygenated organic aerosol (OOA) at the high altitude. Both Nitrate and sulfate can partition between the gas and particle phases. The ratios for HNO3/(N(V) (=gaseous HNO3 + particulate Nitrate) and SO2/(SO2+Sulfate) were found to exhibit quite different distributions between the particles and gas phase for the locations during KORUS-AQ campaign, representing potential for formation of additional particulate nitrate and sulfate. The results of those studies can provide highly resolved temporal and spatial air pollutant, which are valuable for air quality model input parameters for aerosol behaviour.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-03-11

The enhancement of the charge neutrality due to the existence of fine particles is shown to occur generally under microgravity and in one-dimensional structures under gravity. As an application of the latter, the size and position of fine particle clouds relative to surrounding plasmas are determined under gravity. - Highlights: • In fine particle (dusty) plasmas, the charge neutrality is much enhanced by the existence of fine particles. • The enhancement of charge neutrality generally occurs under microgravity and gravity. • Structure of fine particle clouds under gravity is determined by applying the enhanced charge neutrality.

Robust statistical reconstruction for charged particle tomography

Science.gov (United States)

Schultz, Larry Joe; Klimenko, Alexei Vasilievich; Fraser, Andrew Mcleod; Morris, Christopher; Orum, John Christopher; Borozdin, Konstantin N; Sossong, Michael James; Hengartner, Nicolas W

2013-10-08

Systems and methods for charged particle detection including statistical reconstruction of object volume scattering density profiles from charged particle tomographic data to determine the probability distribution of charged particle scattering using a statistical multiple scattering model and determine a substantially maximum likelihood estimate of object volume scattering density using expectation maximization (ML/EM) algorithm to reconstruct the object volume scattering density. The presence of and/or type of object occupying the volume of interest can be identified from the reconstructed volume scattering density profile. The charged particle tomographic data can be cosmic ray muon tomographic data from a muon tracker for scanning packages, containers, vehicles or cargo. The method can be implemented using a computer program which is executable on a computer.

Aerosol Particle Interfacial Thermodynamics and Phase Partitioning Measurements Using Biphasic Microfluidics

Science.gov (United States)

Dutcher, Cari; Metcalf, Andrew

2015-03-01

Secondary organic aerosol particles are nearly ubiquitous in the atmosphere and yet there remain large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. Interfacial properties affect the ambient aerosol morphology, or internal structure of the particle, which in turn can affect the way a particle interacts with an environment of condensable clusters and organic vapors. To improve our ability to accurately predict ambient aerosol morphology, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Unfortunately, many techniques employed to measure interfacial properties do so in bulk solutions or in the presence of a ternary (e.g. solid) phase. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface or interfacial tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred.

Electrostatic Charging and Particle Interactions in Microscopic Insulating Grains

Science.gov (United States)

Lee, Victor

In this thesis, we experimentally investigate the electrostatic charging as well as the particle interactions in microscopic insulating grains. First, by tracking individual grains accelerated in an electric field, we quantitatively demonstrate that tribocharging of same-material grains depends on particle size. Large grains tend to charge positively, and small ones tend to charge negatively. Theories based on the transfer of trapped electrons can explain this tendency but have not been validated. Here we show that the number of trapped electrons, measured independently by a thermoluminescence technique, is orders of magnitude too small to be responsible for the amount of charge transferred. This result reveals that trapped electrons are not responsible for same-material tribocharging of dielectric particles. Second, same-material tribocharging in grains can result in important long-range electrostatic interactions. However, how these electrostatic interactions contribute to particle clustering remains elusive, primarily due to the lack of direct, detailed observations. Using a high-speed camera that falls with a stream charged grains, we observe for the first time how charged grains can undergo attractive as well as repulsive Kepler-like orbits. Charged particles can be captured in their mutual electrostatic potential and form clusters via multiple bounces. Dielectric polarization effects are directly observed, which lead to additional attractive forces and stabilize "molecule-like" arrangements of charged particles. Third, we have developed a new method to study the charge transfer of microscopic particles based on acoustic levitation techniques. This method allows us to narrow the complex problem of many-particle charging down to precise charge measurements of a single sub-millimeter particle colliding with a target plate. By simply attaching nonpolar groups onto glass surfaces, we show that the contact charging of a particle is highly dependent on

Decomposition of Atmospheric Aerosol Phase Function by Particle Size and Morphology via Single Particle Scattering Measurements

Science.gov (United States)

Aptowicz, K. B.; Pan, Y.; Martin, S.; Fernandez, E.; Chang, R.; Pinnick, R. G.

2013-12-01

We report upon an experimental approach that provides insight into how particle size and shape affect the scattering phase function of atmospheric aerosol particles. Central to our approach is the design of an apparatus that measures the forward and backward scattering hemispheres (scattering patterns) of individual atmospheric aerosol particles in the coarse mode range. The size and shape of each particle is discerned from the corresponding scattering pattern. In particular, autocorrelation analysis is used to differentiate between spherical and non-spherical particles, the calculated asphericity factor is used to characterize the morphology of non-spherical particles, and the integrated irradiance is used for particle sizing. We found the fraction of spherical particles decays exponentially with particle size, decreasing from 11% for particles on the order of 1 micrometer to less than 1% for particles over 5 micrometer. The average phase functions of subpopulations of particles, grouped by size and morphology, are determined by averaging their corresponding scattering patterns. The phase functions of spherical and non-spherical atmospheric particles are shown to diverge with increasing size. In addition, the phase function of non-spherical particles is found to vary little as a function of the asphericity factor.

Charged particle discrimination with silicon surface barrier detectors

International Nuclear Information System (INIS)

Coote, G.E.; Pithie, J.; Vickridge, I.C.

1996-01-01

The application for materials analysis of nuclear reactions that give rise to charged particles is a powerful surface analytical and concentration depth profiling technique. Spectra of charged particles, with energies in the range 0.1 to 15 MeV, emitted from materials irradiated with beams of light nuclei such as deuterons are measured with silicon surface barrier detectors. The spectra from multi-elemental materials typically encountered in materials research are usually composed of an overlapping superposition of proton, alpha, and other charged particle spectra. Interpretation of such complex spectra would be simplified if a means were available to electronically discriminate between the detector response to the different kinds of charged particle. We have investigated two methods of discriminating between different types of charged particles. The fast charge pulses from a surface barrier detector have different shapes, depending on the spatial distribution of energy deposition of the incident particle. Fast digitisation of the pulses, followed by digital signal processing provides one avenue for discrimination. A second approach is to use a thin transmission detector in front of a thick detector as a detector telescope. For a given incident energy, different types of charged particles will lose different amounts of energy in the thin detector, providing an alternative means of discrimination. We show that both approaches can provide significant simplification in the interpretation of charged particle spectra in practical situations, and suggest that silicon surface barrier detectors having graded electronic properties could provide improved discrimination compared to the current generation of detectors having homogeneous electronic properties. (author).12 refs., 2 tabs., 28 figs

Wintertime hygroscopicity and volatility of ambient urban aerosol particles

Directory of Open Access Journals (Sweden)

J. Enroth

2018-04-01

Full Text Available Hygroscopic and volatile properties of atmospheric aerosol particles with dry diameters of (20, 50, 75, 110 and 145 nm were determined in situ by using a volatility–hygroscopicity tandem differential mobility analyser (VH-TDMA system with a relative humidity of 90 % and denuding temperature of 270 °C in central Budapest during 2 months in winter 2014–2015. The probability density function of the hygroscopic growth factor (HGF showed a distinct bimodal distribution. One of the modes was characterised by an overall mean HGF of approximately 1.07 (this corresponds to a hygroscopicity parameter κ of 0.033 independently of the particle size and was assigned to nearly hydrophobic (NH particles. Its mean particle number fraction was large, and it decreased monotonically from 69 to 41 % with particle diameter. The other mode showed a mean HGF increasing slightly from 1.31 to 1.38 (κ values from 0.186 to 0.196 with particle diameter, and it was attributed to less hygroscopic (LH particles. The mode with more hygroscopic particles was not identified. The probability density function of the volatility GF (VGF also exhibited a distinct bimodal distribution with an overall mean VGF of approximately 0.96 independently of the particle size, and with another mean VGF increasing from 0.49 to 0.55 with particle diameter. The two modes were associated with less volatile (LV and volatile (V particles. The mean particle number fraction for the LV mode decreased from 34 to 21 % with particle diameter. The bimodal distributions indicated that the urban atmospheric aerosol contained an external mixture of particles with a diverse chemical composition. Particles corresponding to the NH and LV modes were assigned mainly to freshly emitted combustion particles, more specifically to vehicle emissions consisting of large mass fractions of soot likely coated with or containing some water-insoluble organic compounds such as non

Collisional charging of individual submillimeter particles: Using ultrasonic levitation to initiate and track charge transfer

Science.gov (United States)

Lee, Victor; James, Nicole M.; Waitukaitis, Scott R.; Jaeger, Heinrich M.

2018-03-01

Electrostatic charging of insulating fine particles can be responsible for numerous phenomena ranging from lightning in volcanic plumes to dust explosions. However, even basic aspects of how fine particles become charged are still unclear. Studying particle charging is challenging because it usually involves the complexities associated with many-particle collisions. To address these issues, we introduce a method based on acoustic levitation, which makes it possible to initiate sequences of repeated collisions of a single submillimeter particle with a flat plate, and to precisely measure the particle charge in situ after each collision. We show that collisional charge transfer between insulators is dependent on the hydrophobicity of the contacting surfaces. We use glass, which we modify by attaching nonpolar molecules to the particle, the plate, or both. We find that hydrophilic surfaces develop significant positive charges after contacting hydrophobic surfaces. Moreover, we demonstrate that charging between a hydrophilic and a hydrophobic surface is suppressed in an acidic environment and enhanced in a basic one. Application of an electric field during each collision is found to modify the charge transfer, again depending on surface hydrophobicity. We discuss these results within the context of contact charging due to ion transfer, and we show that they lend strong support to O H- ions as the charge carriers.

Aerosol science: theory and practice

International Nuclear Information System (INIS)

Williams, M.M.R.; Loyalka, S.K.

1991-01-01

The purpose of this book is twofold. First, it is intended to give a thorough treatment of the fundamentals of aerosol behavior with rigorous proofs and detailed derivations of the basic equations and removal mechanisms. Second, it is intended to provide practical examples with special attention to radioactive particles and their distribution in size following a radioactive release arising from an accident with a nuclear system. We start with a brief introduction to the applications of aerosol science and the characteristics of aerosols in Chapter 1. In Chapter 2, we devote considerable attention to single and two particle motion with respect to both translation and rotation. Chapter 3 contains extensive discussion of the aerosol general dynamical equation and the dependences of aerosol distributions on size, shape, space, composition, radioactivity, and charge. Important particle rate processes of coagulation, condensation, and deposition/resuspension are discussed in the chapters 4, 6 and 7, respectively. In Chapter 5, we provide a thorough treatment of the analytical and numerical methods used in solving the various forms of the aerosol dynamical equation. We discuss the importance and applications of aerosol science to nuclear technology and, in particular, the nuclear source term in Chapter 8. Our focus in this chapter is on discussions of nuclear accidents that can potentially release large amount of radioactivity to environment. We also discuss the progress that has been made in understanding the natural and engineered aerosol processes that limit or affect such releases. (author)

Unipolar and bipolar diffusion charging of ultrafine particles

International Nuclear Information System (INIS)

Adachi, Motoaki; Okuyama, Kikuo; Kousaka, Yasuo.

1985-01-01

Unipolar and bipolar diffusion charging of monodisperse ultrafine particles of 4 - 100 nm in diameter has been studied experimentally and theoretically. The particles were charged by unipolar and bipolar ions generated by α-ray irradiation and the charge distribution of particles was directly observed in the electric field after the growth of them by condensation of di-butyl phthalate vapor. In both cases of unipolar and bipolar charging, the experimental results have been found in good agreement with the solution of basic equations where Fuchs' formula is used as the combination probability of an ion with a particle. (author)

The single scattering properties of the aerosol particles as aggregated spheres

International Nuclear Information System (INIS)

Wu, Y.; Gu, X.; Cheng, T.; Xie, D.; Yu, T.; Chen, H.; Guo, J.

2012-01-01

The light scattering and absorption properties of anthropogenic aerosol particles such as soot aggregates are complicated in the temporal and spatial distribution, which introduce uncertainty of radiative forcing on global climate change. In order to study the single scattering properties of anthorpogenic aerosol particles, the structures of these aerosols such as soot paticles and soot-containing mixtures with the sulfate or organic matter, are simulated using the parallel diffusion limited aggregation algorithm (DLA) based on the transmission electron microscope images (TEM). Then, the single scattering properties of randomly oriented aerosols, such as scattering matrix, single scattering albedo (SSA), and asymmetry parameter (AP), are computed using the superposition T-matrix method. The comparisons of the single scattering properties of these specific types of clusters with different morphological and chemical factors such as fractal parameters, aspect ratio, monomer radius, mixture mode and refractive index, indicate that these different impact factors can respectively generate the significant influences on the single scattering properties of these aerosols. The results show that aspect ratio of circumscribed shape has relatively small effect on single scattering properties, for both differences of SSA and AP are less than 0.1. However, mixture modes of soot clusters with larger sulfate particles have remarkably important effects on the scattering and absorption properties of aggregated spheres, and SSA of those soot-containing mixtures are increased in proportion to the ratio of larger weakly absorbing attachments. Therefore, these complex aerosols come from man made pollution cannot be neglected in the aerosol retrievals. The study of the single scattering properties on these kinds of aggregated spheres is important and helpful in remote sensing observations and atmospheric radiation balance computations.

Quantum mechanics of charged particle beam optics

CERN Document Server

Khan, Sameen Ahmed

2018-01-01

Theory of charged particle beam optics is basic to the design and working of charged particle beam devices from electron microscopes to accelerator machines. Traditionally, the optical elements of the devices are designed and operated based on classical mechanics and classical electromagnetism, and only certain specific quantum mechanical aspects are dealt with separately using quantum theory. This book provides a systematic approach to quantum theory of charged particle beam optics, particularly in the high energy cases such as accelerators or high energy electron microscopy.

Surface charge accumulation of particles containing radionuclides in open air.

Science.gov (United States)

Kim, Yong-Ha; Yiacoumi, Sotira; Tsouris, Costas

2015-05-01

Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantitative determination of carbonaceous particle mixing state in Paris using single particle mass spectrometer and aerosol mass spectrometer measurements

Science.gov (United States)

Healy, R. M.; Sciare, J.; Poulain, L.; Crippa, M.; Wiedensohler, A.; Prévôt, A. S. H.; Baltensperger, U.; Sarda-Estève, R.; McGuire, M. L.; Jeong, C.-H.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Evans, G. J.; Wenger, J. C.

2013-04-01

Single particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been estimated using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulphate and potassium were compared with concurrent measurements from an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal/optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived mass concentrations reproduced the variability of these species well (R2 = 0.67-0.78), and ten discrete mixing states for carbonaceous particles were identified and quantified. Potassium content was used to identify particles associated with biomass combustion. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorization, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulphate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA/EC ratios. Aged biomass burning OA (OOA2-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidized OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the heterogeneity of primary and

Individual aerosol particles in and below clouds along a Mt. Fuji slope: Modification of sea-salt-containing particles by in-cloud processing

Science.gov (United States)

Ueda, S.; Hirose, Y.; Miura, K.; Okochi, H.

2014-02-01

Sizes and compositions of atmospheric aerosol particles can be altered by in-cloud processing by absorption/adsorption of gaseous and particulate materials and drying of aerosol particles that were formerly activated as cloud condensation nuclei. To elucidate differences of aerosol particles before and after in-cloud processing, aerosols were observed along a slope of Mt. Fuji, Japan (3776 m a.s.l.) during the summer in 2011 and 2012 using a portable laser particle counter (LPC) and an aerosol sampler. Aerosol samples for analyses of elemental compositions were obtained using a cascade impactor at top-of-cloud, in-cloud, and below-cloud altitudes. To investigate composition changes via in-cloud processing, individual particles (0.5-2 μm diameter) of samples from five cases (days) collected at different altitudes under similar backward air mass trajectory conditions were analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. For most cases (four cases), most particles at all altitudes mainly comprised sea salts: mainly Na with some S and/or Cl. Of those, in two cases, sea-salt-containing particles with Cl were found in below-cloud samples, although sea-salt-containing particles in top-of-cloud samples did not contain Cl. This result suggests that Cl in the sea salt was displaced by other cloud components. In the other two cases, sea-salt-containing particles on samples at all altitudes were without Cl. However, molar ratios of S to Na (S/Na) of the sea-salt-containing particles of top-of-cloud samples were higher than those of below-cloud samples, suggesting that sulfuric acid or sulfate was added to sea-salt-containing particles after complete displacement of Cl by absorption of SO2 or coagulation with sulfate. The additional volume of sulfuric acid in clouds for the two cases was estimated using the observed S/Na values of sea-salt-containing particles. The estimation revealed that size changes by in

Physical properties of the arctic summer aerosol particles in relation ...

Indian Academy of Sciences (India)

The sea-salt particles of marine origin generated within the Arctic circle are identified as the main source of the Arctic summer aerosols. ... concentration starts decreasing within a few minutes from the start of these events but requires a few hours to restore to the normal background aerosol level after the end of event.

Aerosol nucleation induced by a high energy particle beam

DEFF Research Database (Denmark)

Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

2011-01-01

We have studied sulfuric acid aerosol nucleation in an atmospheric pressure reaction chamber using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear contribution from ion-induced nucleation and consider this to be the first unambiguous observation of the ion......-effect on aerosol nucleation using a particle beam under conditions that resemble the Earth's atmosphere. By comparison with ionization using a gamma source we further show that the nature of the ionizing particles is not important for the ion-induced component of the nucleation. This implies that inexpensive...... ionization sources - as opposed to expensive accelerator beams - can be used for investigations of ion-induced nucleation....

A Search for Free Fractional Electric Charge Elementary Particles

Energy Technology Data Exchange (ETDEWEB)

Halyo, Valerie

2000-12-04

A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup -22} particles per nucleon with 95% confidence.

A Search for Free Fractional Electric Charge Elementary Particles

Energy Technology Data Exchange (ETDEWEB)

Halyo, Valerie

2000-12-04

A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied| about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup -22} particles per nucleon with 95% confidence.

Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere

Directory of Open Access Journals (Sweden)

Keiichiro Hara

2010-12-01

Full Text Available Tethered balloon-borne aerosol measurements were carried out at Syowa Station, Antarctica during the 46th Japanese Antarctic Research Expedition. CN concentration had a maximum in the summer, whereas the number concentrations of fine particles (D_p>0.3 μm and coarse particles (D_p>2.0 μm increased during the winter-spring. The range of CN concentration was 30-2200 cm^ near the surface (surface-500 m and 7-7250 cm^ in the lower free troposphere (>1500 m. During the austral summer, higher CN concentration was often observed in the lower free troposphere. Frequent appearance of higher CN concentration in the free troposphere relative to the surface measurements strongly suggests that new particle formation in the Antarctic regions occurs in the lower free troposphere. Single particle analysis indicated that most of the aerosol particles during the winter were composed of Mg-enriched sea-salt particles originated from sea-salt fractionation on the sea-ice and their modified particles by NO_3^ and SO_4^. This suggests that sea-salt fractionation on sea-ice and modification of sea-salt particles were affected greatly by aerosol hygroscopicity during the winter. Antarctic haze layer was observed not only in the boundary layer but also in the lower free troposphere.

Single particle characterization, source apportionment, and aging effects of ambient aerosols in Southern California

Science.gov (United States)

Shields, Laura Grace

Composed of a mixture of chemical species and phases and existing in a variety of shapes and sizes, atmospheric aerosols are complex and can have serious influence on human health, the environment, and climate. In order to better understand the impact of aerosols on local to global scales, detailed measurements on the physical and chemical properties of ambient particles are essential. In addition, knowing the origin or the source of the aerosols is important for policymakers to implement targeted regulations and effective control strategies to reduce air pollution in their region. One of the most ground breaking techniques in aerosol instrumentation is single particle mass spectrometry (SPMS), which can provide online chemical composition and size information on the individual particle level. The primary focus of this work is to further improve the ability of one specific SPMS technique, aerosol time-of-flight mass spectrometry (ATOFMS), for the use of identifying the specific origin of ambient aerosols, which is known as source apportionment. The ATOFMS source apportionment method utilizes a library of distinct source mass spectral signatures to match the chemical information of the single ambient particles. The unique signatures are obtained in controlled source characterization studies, such as with the exhaust emissions of heavy duty diesel vehicles (HDDV) operating on a dynamometer. The apportionment of ambient aerosols is complicated by the chemical and physical processes an individual particle can undergo as it spends time in the atmosphere, which is referred to as "aging" of the aerosol. Therefore, the performance of the source signature library technique was investigated on the ambient dataset of the highly aged environment of Riverside, California. Additionally, two specific subsets of the Riverside dataset (ultrafine particles and particles containing trace metals), which are known to cause adverse health effects, were probed in greater detail. Finally

Representation of aerosol particles and associated transport pathways in regional climate modelling in Africa

CSIR Research Space (South Africa)

Garland, Rebecca M

2016-11-01

Full Text Available Aerosol particles can have large impacts on air quality and on the climate system. Regional climate models for Africa have not been well-tested and validated for their representation and simulation of aerosol particles. This study aimed to validate...

Development and experimental evaluation of an optical sensor for aerosol particle characterization

Energy Technology Data Exchange (ETDEWEB)

Somesfalean, G.

1998-03-01

A sensor for individual aerosol particle characterization, based on a single-mode semiconductor laser coupled to an external cavity is presented. The light emitting semiconductor laser acts as a sensitive optical detector itself, and the whole system has the advantage of using conventional optical components and providing a compact set-up. Aerosol particles moving through the sensing volume, which is located in the external cavity of a semiconductor laser, scatter and absorb light. Thereby they act as small disturbances on the electromagnetic field inside the dynamic multi-cavity laser system. From the temporal variation of the output light intensity, information about the number, velocity, size, and refractive index of the aerosol particles can be derived. The diffracted light in the near-forward scattering direction is collected and Fourier-transformed by a lens, and subsequently imaged on a CCD camera. The recorded Fraunhofer diffraction pattern provides information about the projected area of the scattering particle, and can thus be used to determine the size and the shape of aerosol particles. The sensor has been tested on fibers which are of interest in the field of working environment monitoring. The recorded output intensity variation has been analysed, and the relationship between the shape and the size of each fibre, and the resulting scattering profiles has been investigated. A simple one-dimensional model for the optical feedback variation due to the light-particle interaction in the external cavity is also discussed 34 refs, 26 figs, 6 tabs

A novel tandem differential mobility analyzer with organic vapor treatment of aerosol particles

Directory of Open Access Journals (Sweden)

J. Joutsensaari

2001-01-01

Full Text Available A novel method to characterize the organic composition of aerosol particles has been developed. The method is based on organic vapor interaction with aerosol particles and it has been named an Organic Tandem Differential Mobility Analyzer (OTDMA. The OTDMA method has been tested for inorganic (sodium chloride and ammonium sulfate and organic (citric acid and adipic acid particles. Growth curves of the particles have been measured in ethanol vapor and as a comparison in water vapor as a function of saturation ratio. Measurements in water vapor show that sodium chloride and ammonium sulfate as well as citric acid particles grow at water saturation ratios (S of 0.8 and above, whereas adipic acid particles do not grow at S S = 0.75 and S = 0.79, respectively. Citric acid particles grow monotonously with increasing saturation ratios already at low saturation ratios and no clear deliquescence point is found. For sodium chloride and ammonium sulfate particles, no growth can be seen in ethanol vapor at saturation ratios below 0.93. In contrast, for adipic acid particles, the deliquescence takes place at around S = 0.95 in the ethanol vapor. The recrystallization of adipic acid takes place at S The results show that the working principles of the OTDMA are operational for single-component aerosols. Furthermore, the results indicate that the OTDMA method may prove useful in determining whether aerosol particles contain organic substances, especially if the OTDMA is operated in parallel with a hygroscopicity TDMA, as the growth of many substances is different in ethanol and water vapors.

Chemical composition of individual aerosol particles from working areas in a nickel refinery.

Science.gov (United States)

Höflich, B L; Wentzel, M; Ortner, H M; Weinbruch, S; Skogstad, A; Hetland, S; Thomassen, Y; Chaschin, V P; Nieboer, E

2000-06-01

Individual aerosol particles (n = 1170) collected at work stations in a nickel refinery were analyzed by wavelength-dispersive electron-probe microanalysis. By placing arbitrary restrictions on the contents of sulfur and silicon, the particles could be divided into four main groups. Scanning electron images indicated that most of the particles examined were relatively small (refinery intermediates. The implications of the findings for aerosol speciation measurements, toxicological studies and interpretation of adverse health effects are explored.

Display of charged ionizing particles

International Nuclear Information System (INIS)

Cano S, D.; Ortiz A, M. D.; Amarillas S, L. E.; Vega C, H. R.

2017-10-01

The human being is exposed to sources of ionizing and non-ionizing radiation, both of natural or anthropogenic origin. None of these, except non-ionizing such as visible light and infrared radiation, can be detected by the sense of sight and touch respectively. The sun emits charged particles with speeds close to the light that interact with the atoms of the gases present in the atmosphere, producing nuclear reactions that in turn produce other particles that reach the surface of the Earth and reach the living beings. On Earth there are natural radioisotopes that, when they disintegrate, emit ionizing radiation that contributes to the dose we receive. A very old system that allows the visualization of the trajectories of the charged ionizing particles is the Fog Chamber that uses a saturated steam that when crossed by particles with mass and charge, as alpha and beta particles produce condensation centers along its path leaves a trace that can be seen. The objective of this work was to build a fog chamber using easily accessible materials. To measure the functioning of the fog chamber, cosmic rays were measured, as well as a source of natural metal uranium. The fog chamber allowed seeing the presence of traces in alcohol vapor that are produced in a random way. Introducing the uranium foil inside the fog chamber, traces of alpha particles whose energy varies from 4 to 5 MeV were observed. (Author)

Determination of the particle size distribution of aerosols by means of a diffusion battery

International Nuclear Information System (INIS)

Maigne, J.P.

1978-09-01

The different methods allowing to determine the particle size distribution of aerosols by means of diffusion batteries are described. To that purpose, a new method for the processing of experimental data (percentages of particles trapped by the battery vs flow rate) was developed on the basis of calculation principles which are described and assessed. This method was first tested by numerical simulation from a priori particle size distributions and then verified experimentally using a fine uranine aerosol whose particle size distribution as determined by our method was compared with the distribution previously obtained by electron microscopy. The method can be applied to the determination of particle size distribution spectra of fine aerosols produced by 'radiolysis' of atmospheric gaseous impurities. Two other applications concern the detection threshold of the condensation nuclei counter and the 'critical' radii of 'radiolysis' particles [fr

The 1st symposium of Research Center for Charged Particle Therapy on fundamental development of the charged particle therapy

International Nuclear Information System (INIS)

Soga, Fuminori

2002-06-01

This issue is the collection of the paper presented at the 1st Symposium of Research Center for Charged Particle Therapy on fundamental development of the charged particle therapy. The 31 of the presented papers are indexed individually. (J.P.N.)

Elemental composition of aerosol particles from two atmospheric monitoring stations in the Amazon Basin

International Nuclear Information System (INIS)

Artaxo, P.; Gerab, F.; Rabello, M.L.C.

1993-01-01

One key region for the study of processes that are changing the composition of the global atmosphere is the Amazon Basin tropical rain forest. The high rate of deforestation and biomass burning is emitting large amounts of gases and fine-mode aerosol particles to the global atmosphere. Two background monitoring stations are operating continuously measuring aerosol composition, at Cuiaba, and Serra do Navio. Fine- and coarse-mode aerosol particles are being collected using stacked filter units. Particle induced X-ray emission (PIXE) was used to measure concentrations of up to 21 elements: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, and Pb. The elemental composition was measured at the new PIXE facility from the University of Sao Paulo, using a dedicated 5SDH tandem Pelletron nuclear accelerator. Absolute principal factor analysis (APFA) has derived absolute elemental source profiles. At the Serra do Navio sampling site a very clean background aerosol is being observed. Biogenic aerosol dominates the fine-mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and FPM. Three components dominate the aerosol composition: Soil dust particles, the natural biogenic release by the forest, and a marine aerosol component. At the Cuiaba site, during the dry season, a strong component of biomass burning is observed. An aerosol mass concentration up to 120 μg/m 3 was measured. APFA showed three components: Soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, FPM, K, Cl) and natural biogenic particles (K, S, Ca, Mn, Zn). The fine-mode biogenic component of both sites shows remarkable similarities, although the two sampling sites are 3000 km apart. Several essential plant nutrients like P, K, S, Ca, Ni and others are transported in the atmosphere as a result of biomass burning processes. (orig.)

Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

Directory of Open Access Journals (Sweden)

R. M. Healy

2013-09-01

Full Text Available Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC, organic aerosol (OA, ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, a thermal–optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC. ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R2 = 0.67–0.78, and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA is associated with two mixing states which differ significantly in their OA / EC ratios. Aged biomass burning OA (OOA2-BBOA was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the

Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

Science.gov (United States)

Healy, R. M.; Sciare, J.; Poulain, L.; Crippa, M.; Wiedensohler, A.; Prévôt, A. S. H.; Baltensperger, U.; Sarda-Estève, R.; McGuire, M. L.; Jeong, C.-H.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Evans, G. J.; Wenger, J. C.

2013-09-01

Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal-optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R2 = 0.67-0.78), and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA / EC ratios. Aged biomass burning OA (OOA2-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the temporal

On the secondary charging effects and structure of mesospheric dust particles impacting on rocket probes

Directory of Open Access Journals (Sweden)

O. Havnes

2007-03-01

Full Text Available The dust probe DUSTY, first launched during the summer of 1994 (flights ECT–02 and ECT–07 from Andøya Rocket Range, northern Norway, was the first probe to unambiguously detect heavy charged mesospheric aerosols, from hereon referred to as dust. In ECT–02 the probe detected negatively charged dust particles in the height interval of 83 to 88.5 km. In this flight, the lower grid in the detector (Grid 2 measures both positive and negative currents in various regions, and we find that the relationship between the current measurements of Grid 2 and the bottom plate can only be explained by influence from secondary charge production on Grid 2. In ECT–07, which had a large coning, positive currents reaching the top grid of the probe were interpreted as due to the impact of positively charged dust particles. We have now reanalyzed the data from ECT–07 and arrived at the conclusion that the measured positive currents to this grid must have been mainly due to secondary charging effects from the impacting dust particles. The grid consists of a set of parallel wires crossed with an identical set of wires on top of it, and we find that if the observed currents were created from the direct impact of charged dust particles, then they should be very weakly modulated at four times the rocket spin rate ωR. Observations show, however, that the observed currents are strongly modulated at 2ωR. We cannot reproduce the observed large modulations of the impact currents in the dust layer if the currents are due only to the transfer of the charges on the impacted dust particles. Based on the results of recent ice cluster impact secondary charging experiments by Tomsic (2003, which found that a small fraction of the ice clusters, when impacting with nearly grazing incidence, carried away one negative charge −1e, we have arrived at the conclusion that similar, but significantly more effective, charging effects must be predominantly responsible for the

MISR Dark Water aerosol retrievals: operational algorithm sensitivity to particle non-sphericity

Directory of Open Access Journals (Sweden)

O. V. Kalashnikova

2013-08-01

Full Text Available The aim of this study is to theoretically investigate the sensitivity of the Multi-angle Imaging SpectroRadiometer (MISR operational (version 22 Dark Water retrieval algorithm to aerosol non-sphericity over the global oceans under actual observing conditions, accounting for current algorithm assumptions. Non-spherical (dust aerosol models, which were introduced in version 16 of the MISR aerosol product, improved the quality and coverage of retrievals in dusty regions. Due to the sensitivity of the retrieval to the presence of non-spherical aerosols, the MISR aerosol product has been successfully used to track the location and evolution of mineral dust plumes from the Sahara across the Atlantic, for example. However, the MISR global non-spherical aerosol optical depth (AOD fraction product has been found to have several climatological artifacts superimposed on valid detections of mineral dust, including high non-spherical fraction in the Southern Ocean and seasonally variable bands of high non-sphericity. In this paper we introduce a formal approach to examine the ability of the operational MISR Dark Water algorithm to distinguish among various spherical and non-spherical particles as a function of the variable MISR viewing geometry. We demonstrate the following under the criteria currently implemented: (1 Dark Water retrieval sensitivity to particle non-sphericity decreases for AOD below about 0.1 primarily due to an unnecessarily large lower bound imposed on the uncertainty in MISR observations at low light levels, and improves when this lower bound is removed; (2 Dark Water retrievals are able to distinguish between the spherical and non-spherical particles currently used for all MISR viewing geometries when the AOD exceeds 0.1; (3 the sensitivity of the MISR retrievals to aerosol non-sphericity varies in a complex way that depends on the sampling of the scattering phase function and the contribution from multiple scattering; and (4 non

TEM study of soot, organic aerosol, and sea-salt particles collected during CalNex

Science.gov (United States)

Adachi, K.; Buseck, P. R.

2010-12-01

Anthropogenic aerosol particles are emitted in abundance from megacities. Those particles can have important effects on both human health and climate. In this study, aerosol particles having aerodynamic diameters between 50 and 300 nm were collected during the CalNex campaign at the Pasadena ground site from May 15 to June 15, 2010, ~15 km northeast of downtown Los Angeles. The samples were analyzed using transmission electron microscopes (TEMs) to characterize particle shapes and compositions. Most samples are dominated by soot, organic aerosol (OA), sulfate, sea salt, or combinations thereof. Sizes and amounts of OA particles increased during the afternoons, and most soot particles were internally mixed with OA and sulfate in the afternoons. The proportion of soot to other material in individual particles increased and soot particles were more compact during the nights and early mornings. Sea-salt particles were commonly internally mixed with other materials. They have high Na contents with lesser N, Mg, S, K, and Ca and almost no Cl, suggesting that the Cl was replaced by sulfate or nitrate in the atmosphere. There is less OA and more sea salt and sulfate in the CalNex samples than in the samples from Mexico City that were collected during the MILAGRO campaign. Our study indicates that compositions of internally mixed aerosol particles and shapes of soot particles change significantly within a day. These changes probably influence the estimates of their effects on human health and climate.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

Science.gov (United States)

Pfrang, C.; Shiraiwa, M.; Pöschl, U.

2011-07-01

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles approximating atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant timescales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

Directory of Open Access Journals (Sweden)

C. Pfrang

2011-07-01

Full Text Available Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles approximating atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant timescales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

The generation of diesel exhaust particle aerosols from a bulk source in an aerodynamic size range similar to atmospheric particles

Directory of Open Access Journals (Sweden)

Daniel J Cooney

2008-08-01

Full Text Available Daniel J Cooney1, Anthony J Hickey21Department of Biomedical Engineering; 2School of Pharmacy, University of North Carolina, Chapel Hill, NC, USAAbstract: The influence of diesel exhaust particles (DEP on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene in the particles resulting from the aerosolization process.Keywords: diesel exhaust particles, aerosol, inhalation toxicology

Particle integrity, sampling, and application of a DNA-tagged tracer for aerosol transport studies

Energy Technology Data Exchange (ETDEWEB)

Kaeser, Cynthia Jeanne [Michigan State Univ., East Lansing, MI (United States)

2017-07-21

Aerosols are an ever-present part of our daily environment and have extensive effects on both human and environmental health. Particles in the inhalable range (1-10 μm diameter) are of particular concern because their deposition in the lung can lead to a variety of illnesses including allergic reactions, viral or bacterial infections, and cancer. Understanding the transport of inhalable aerosols across both short and long distances is necessary to predict human exposures to aerosols. To assess the transport of hazardous aerosols, surrogate tracer particles are required to measure their transport through occupied spaces. These tracer particles must not only possess similar transport characteristics to those of interest but also be easily distinguished from the background at low levels and survive the environmental conditions of the testing environment. A previously-developed DNA-tagged particle (DNATrax), composed of food-grade sugar and a DNA oligonucleotide as a “barcode” label, shows promise as a new aerosol tracer. Herein, the use of DNATrax material is validated for use in both indoor and outdoor environments. Utilizing passive samplers made of materials commonly found in indoor environments followed by quantitative polymerase chain reaction (qPCR) assay for endpoint particle detection, particles detection was achieved up to 90 m from the aerosolization location and across shorter distances with high spatial resolution. The unique DNA label and PCR assay specificity were leveraged to perform multiple simultaneous experiments. This allowed the assessment of experimental reproducibility, a rare occurrence among aerosol field tests. To transition to outdoor testing, the solid material provides some protection of the DNA label when exposed to ultraviolet (UV) radiation, with 60% of the DNA remaining intact after 60 minutes under a germicidal lamp and the rate of degradation declining with irradiation time. Additionally, exposure of the DNATrax material using

Photochemical aging of aerosol particles in different air masses arriving at Baengnyeong Island, Korea

Science.gov (United States)

Kang, Eunha; Lee, Meehye; Brune, William H.; Lee, Taehyoung; Park, Taehyun; Ahn, Joonyoung; Shang, Xiaona

2018-05-01

Atmospheric aerosol particles are a serious health risk, especially in regions like East Asia. We investigated the photochemical aging of ambient aerosols using a potential aerosol mass (PAM) reactor at Baengnyeong Island in the Yellow Sea during 4-12 August 2011. The size distributions and chemical compositions of aerosol particles were measured alternately every 6 min from the ambient air or through the highly oxidizing environment of a potential aerosol mass (PAM) reactor. Particle size and chemical composition were measured by using the combination of a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Inside the PAM reactor, O3 and OH levels were equivalent to 4.6 days of integrated OH exposure at typical atmospheric conditions. Two types of air masses were distinguished on the basis of the chemical composition and the degree of aging: air transported from China, which was more aged with a higher sulfate concentration and O : C ratio, and the air transported across the Korean Peninsula, which was less aged with more organics than sulfate and a lower O : C ratio. For both episodes, the particulate sulfate mass concentration increased in the 200-400 nm size range when sampled through the PAM reactor. A decrease in organics was responsible for the loss of mass concentration in 100-200 nm particles when sampled through the PAM reactor for the organics-dominated episode. This loss was especially evident for the m/z 43 component, which represents less oxidized organics. The m/z 44 component, which represents further oxidized organics, increased with a shift toward larger sizes for both episodes. It is not possible to quantify the maximum possible organic mass concentration for either episode because only one OH exposure of 4.6 days was used, but it is clear that SO2 was a primary precursor of secondary aerosol in northeast Asia, especially during long-range transport from China. In addition

In situ measurement of electrostatic charge and charge distribution on flyash particles in power station exhaust stream

Energy Technology Data Exchange (ETDEWEB)

Guang, D.

1992-01-01

The electrostatic charges and charge distributions on individual flyash particles were experimentally measured in situ at four power stations in New South Wales and in the laboratory with an Electrostatic Charge Classifier. The global charge of these flyashes was also measured. The electrostatic charge on flyash particles of four power stations was found to be globally native. The median charge on the flyash particles varies linearly with particle diameter for all four flyashes. The electrostatic charge on the Tallawarra flyash particles was found to increase after passage through the air heater having huge metal surface areas, suggesting that triboelectrification was the primary charging mechanism for flyash particles. Distinctly different characteristics of the electrostatic charge, particle size and particle shape were found between the Eraring and the Tallawarra flyashes. The spherical Eraring ash has the highest proportion of lines and positively charged particles, but the lowest global charge level among the four flyashes. In contrast, the Tallawarra flyash has just the opposite. It is the distinct characteristics of the flyashes from Eraring and Tallawarra power stations that are responsible for the significant differences in their baghouse performance. The napping feature on the surface of the filter bags used in the Eraring and Tallawarra power stations provides an upstream surface of low fibre density above the fabric bulk. This feature presents and advantage to highly charged particles, like the Tallawarra flyash particles. Highly charged particles tend to deposit on such an upstream surface resulting in a porous dust cake with much less contact areas with the fabric medium than would otherwise be formed. This cake is easy to remove and provides less resistance to the gas flow. After singeing the naps on the filter bag surface at the Eraring power station, the problems of high pressure drop and retention of dust cake on the bas surface have been resolved.

Deposition of biomass combustion aerosol particles in the human respiratory tract.

Science.gov (United States)

Löndahl, Jakob; Pagels, Joakim; Boman, Christoffer; Swietlicki, Erik; Massling, Andreas; Rissler, Jenny; Blomberg, Anders; Bohgard, Mats; Sandström, Thomas

2008-08-01

Smoke from biomass combustion has been identified as a major environmental risk factor associated with adverse health effects globally. Deposition of the smoke particles in the lungs is a crucial factor for toxicological effects, but has not previously been studied experimentally. We investigated the size-dependent respiratory-tract deposition of aerosol particles from wood combustion in humans. Two combustion conditions were studied in a wood pellet burner: efficient ("complete") combustion and low-temperature (incomplete) combustion simulating "wood smoke." The size-dependent deposition fraction of 15-to 680-nm particles was measured for 10 healthy subjects with a novel setup. Both aerosols were extensively characterized with regard to chemical and physical particle properties. The deposition was additionally estimated with the ICRP model, modified for the determined aerosol properties, in order to validate the experiments and allow a generalization of the results. The measured total deposited fraction of particles from both efficient combustion and low-temperature combustion was 0.21-0.24 by number, surface, and mass. The deposition behavior can be explained by the size distributions of the particles and by their ability to grow by water uptake in the lungs, where the relative humidity is close to saturation. The experiments were in basic agreement with the model calculations. Our findings illustrate: (1) that particles from biomass combustion obtain a size in the respiratory tract at which the deposition probability is close to its minimum, (2) that particle water absorption has substantial impact on deposition, and (3) that deposition is markedly influenced by individual factors.

Metastable states of plasma particles close to a charged surface

Energy Technology Data Exchange (ETDEWEB)

Shavlov, A. V., E-mail: shavlov@ikz.ru [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation); Tyumen State Oil and Gas University, 38, Volodarskogo St., 625000, Tyumen (Russian Federation); Dzhumandzhi, V. A. [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation)

2015-09-15

The free energy of the plasma particles and the charged surface that form an electroneutral system is calculated on the basis of the Poisson-Boltzmann equation. It is shown that, owing to correlation of light plasma particles near the charged surface and close to heavy particles of high charge, there can be metastable states in plasma. The corresponding phase charts of metastable states of the separate components of plasma, and plasma as a whole, are constructed. These charts depend on temperature, the charge magnitude, the size of the particles, and the share of the charge of the light carriers out of the total charge of the plasma particles.

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.

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

Science.gov (United States)

Williams, Monique; Villarreal, Amanda; Bozhilov, Krassimir; Lin, Sabrina; Talbot, Prue

2013-01-01

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.

Bibliography of integral charged particle nuclear data. Archival edition

International Nuclear Information System (INIS)

Burrows, T.W.; Dempsey, P.

1980-03-01

This is the fourth annual edition of the National Nuclear Data Center charged-particle bibliography. This edition is cumulative and supersedes the previous editions. The bibliography's primary aims are to satisfy the need for a concise and comprehensive index of integral charged-particle cross section data and to provide an index of charged-particle data compiled in the international exchange format. References in this Part are by target for the various incident charged particles (in order of increasing A). The present publication is an archival volume; future publications will be cumulative supplements to this edition

Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

International Nuclear Information System (INIS)

Kim, Yong-ha; Yiacoumi, Sotira

2016-01-01

Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM) to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequent effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 0.04 micrometers and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and an atmospheric system containing radioactive particles. Limitations of the approaches are discussed.

Slowing of charged particles by particle methods

International Nuclear Information System (INIS)

Mercier, B.

1985-03-01

We review some facts about particle methods for solving linear hyperbolic equations. We show how one gets an evaluation of integral quantities like: ∫ u(x,t) zeta(x,t) dxdt where u denotes the solution and zeta an arbitrary weight function. Then, we apply the method to the equation describing charged particle transport in a plasma with emphasis on the evaluation of energy deposition on ions and electrons [fr

MAPPIX: A software package for off-line micro-pixe single particle aerosol analysis

International Nuclear Information System (INIS)

Ceccato, D.

2009-01-01

In the framework of a multiannual experiment performed at Baia Terra Nova, Antarctica, size-segregated aerosol samples were collected by using a 12-stage SDI impactor (Hillamo design). Approximately 2800 particles, belonging to the first four supermicrometric SDI stages - 8.39, 4.08, 2.68, 1.66 μm dynamic aerosol diameter cuts - were analyzed at the INFN-LNL micro-PIXE facility, a three lens Oxford Microprobe (OM) product, installed in the early nineties. Four regions on each of the 12 sub-samples were measured; 60 aerosol particles were detected on average in each of the analyzed regions. The off-line single aerosol particle (SAP) analysis of such big amount of data required software that is able to rapidly handle the acquired data, with a simple and fast area selection procedure; the subsequent automated PIXE spectra analysis with a specialized code was also needed. The MAPPIX 2.0 software was designed to make easier and faster the user jobs during the SAP analysis. The package is composed of two separate routines: the first one is devoted to data format conversion (OM-LMF file format to MAPPIX format), while the second one is devoted to micro-PIXE maps graphical presentation and aerosol particle selection procedure. The MAPPIX data format and software features will be discussed; a short report of the speed performances will be presented.

Glyoxal processing by aerosol multiphase chemistry: towards a kinetic modeling framework of secondary organic aerosol formation in aqueous particles

Directory of Open Access Journals (Sweden)

B. Ervens

2010-09-01

Full Text Available This study presents a modeling framework based on laboratory data to describe the kinetics of glyoxal reactions that form secondary organic aerosol (SOA in aqueous aerosol particles. Recent laboratory results on glyoxal reactions are reviewed and a consistent set of empirical reaction rate constants is derived that captures the kinetics of glyoxal hydration and subsequent reversible and irreversible reactions in aqueous inorganic and water-soluble organic aerosol seeds. Products of these processes include (a oligomers, (b nitrogen-containing products, (c photochemical oxidation products with high molecular weight. These additional aqueous phase processes enhance the SOA formation rate in particles and yield two to three orders of magnitude more SOA than predicted based on reaction schemes for dilute aqueous phase (cloud chemistry for the same conditions (liquid water content, particle size.

The application of the new module including detailed chemical processes in a box model demonstrates that both the time scale to reach aqueous phase equilibria and the choice of rate constants of irreversible reactions have a pronounced effect on the predicted atmospheric relevance of SOA formation from glyoxal. During day time, a photochemical (most likely radical-initiated process is the major SOA formation pathway forming ∼5 μg m⁻³ SOA over 12 h (assuming a constant glyoxal mixing ratio of 300 ppt. During night time, reactions of nitrogen-containing compounds (ammonium, amines, amino acids contribute most to the predicted SOA mass; however, the absolute predicted SOA masses are reduced by an order of magnitude as compared to day time production. The contribution of the ammonium reaction significantly increases in moderately acidic or neutral particles (5 < pH < 7.

Glyoxal uptake into ammonium sulfate seed under dark conditions can be represented with a single reaction parameter k_effupt that does not depend

Bibliography of integral charged particle nuclear data

International Nuclear Information System (INIS)

Holden, N.E.; Burrows, T.W.

1982-03-01

This publication is the second supplement to the archival edition of the National Nuclear Data Center's charged-particle bibliography. This supplement contains citations to all references scanned since March 15, 1981, and all corrections and additions to previous citations, and indexes all data received in the international exchanged format (EXFOR). The primary goal of the bibliography has been to satisfy the need expressed by the Nuclear Reaction Data Center Network for a concise and comprehensive bibliography of integral charged-particle cross section data and to provide an index of data exchanged among the members. In 1980, coverage was expanded to include differential data relevant to charged-particle-induced neutron-source reactions

Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

Science.gov (United States)

Lee, Alex K. Y.; Chen, Chia-Li; Liu, Jun; Price, Derek J.; Betha, Raghu; Russell, Lynn M.; Zhang, Xiaolu; Cappa, Christopher D.

2017-12-01

Black carbon (BC) emitted from incomplete combustion can result in significant impacts on air quality and climate. Understanding the mixing state of ambient BC and the chemical characteristics of its associated coatings is particularly important to evaluate BC fate and environmental impacts. In this study, we investigate the formation of organic coatings on BC particles in an urban environment (Fontana, California) under hot and dry conditions using a soot-particle aerosol mass spectrometer (SP-AMS). The SP-AMS was operated in a configuration that can exclusively detect refractory BC (rBC) particles and their coatings. Using the -log(NOx / NOy) ratio as a proxy for photochemical age of air masses, substantial formation of secondary organic aerosol (SOA) coatings on rBC particles was observed due to active photochemistry in the afternoon, whereas primary organic aerosol (POA) components were strongly associated with rBC from fresh vehicular emissions in the morning rush hours. There is also evidence that cooking-related organic aerosols were externally mixed from rBC. Positive matrix factorization and elemental analysis illustrate that most of the observed SOA coatings were freshly formed, providing an opportunity to examine SOA coating formation on rBCs near vehicular emissions. Approximately 7-20 wt % of secondary organic and inorganic species were estimated to be internally mixed with rBC on average, implying that rBC is unlikely the major condensation sink of SOA in this study. Comparison of our results to a co-located standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) measurement suggests that at least a portion of SOA materials condensed on rBC surfaces were chemically different from oxygenated organic aerosol (OOA) particles that were externally mixed with rBC, although they could both be generated from local photochemistry.

Hygroscopic Properties and Chemical Composition of Aerosol Particles at the High Alpine Site Jungfraujoch

Energy Technology Data Exchange (ETDEWEB)

Weingarter, E.; Gysel, M.; Sjoegren, S.; Baltesperger, U.; Alfarra, R.; Bower, K.; Coe, H.

2004-03-01

The hygroscopic properties of aerosols play a significant role in atmospheric phenomena such as acid deposition, visibility degradation and climate change. Due to the hygroscopic growth of the particles, water is often the dominant component of the ambient aerosol at high relative humidity (RH) conditions. The ability to absorb water depends on the particle chemical composition, dry size, and shape. The aim of this study is to link the chemical composition of the atmospheric aerosol to its hygroscopic properties. (author)

The impact of aerosol composition on the particle to gas partitioning of reactive mercury.

Science.gov (United States)

Rutter, Andrew P; Schauer, James J

2007-06-01

A laboratory system was developed to study the gas-particle partitioning of reactive mercury (RM) as a function of aerosol composition in synthetic atmospheric particulate matter. The collection of RM was achieved by filter- and sorbent-based methods. Analyses of the RM collected on the filters and sorbents were performed using thermal extraction combined with cold vapor atomic fluorescence spectroscopy (CVAFS), allowing direct measurement of the RM load on the substrates. Laboratory measurements of the gas-particle partitioning coefficients of RM to atmospheric aerosol particles revealed a strong dependence on aerosol composition, with partitioning coefficients that varied by orders of magnitude depending on the composition of the particles. Particles of sodium nitrate and the chlorides of potassium and sodium had high partitioning coefficients, shifting the RM partitioning toward the particle phase, while ammonium sulfate, levoglucosan, and adipic acid caused the RM to partition toward the gas phase and, therefore, had partitioning coefficients that were lower by orders of magnitude.

Charged particle scintillation mass spectrometer

International Nuclear Information System (INIS)

Baranov, P.S.; Zhuravlev, E.E.; Nafikov, A.A.; Osadchi , A.I.; Raevskij, V.G.; Smirnov, P.A.; Cherepnya, S.N.; Yanulis, Yu.P.

1982-01-01

A scintillation mass-spectrometer for charged particle identification by the measured values of time-of-flight and energy operating on line with the D-116 computer is described. Original time detectors with 100x100x2 mm 3 and 200x2 mm 2 scintillators located on the 1- or 2 m path length are used in the spectrometer. The 200x200x200 mm 3 scintillation unit is used as a E-counter. Time-of-flight spectra of the detected particles on the 2 m path length obtained in spectrometer test in the beam of charged particles escaping from the carbon target at the angle of 130 deg under 1.2 GeV bremsstrahlung beam of the ''Pakhra'' PIAS synchrotron are presented. Proton and deuteron energy spectra as well as mass spectrum of all the particles detected by the spectrometer are given. Mass resolution obtained on the 2 m path length for π-mesons is +-25%, for protons is +-5%, for deuterons is +-3%

Compact and portable system for evaluation of individual exposure at aerosol particle in urban area

International Nuclear Information System (INIS)

De Zaiacomo, T.

1995-01-01

A compact and portable system for real-time acquisition of aerosol concentration data in urban and extra-urban area is presented. It is based on two optical type aerosol monitors integrated by aerosol particle separating and collecting devices, assembled into a carrying case together with temperature and relative humidity sensors and a programmable analog data logger; data output is addressed to a dedicated printer or personal computer. Further data about particle size, morphological aspect and particle mass concentration are obtainable by weighing supports used to concurrently collect aerosol particles and/or by means of microanalytical techniques. System performances are evaluated from the point of view of portability, possibility of use as stationary sampler for long-term monitoring purposes and coherence between optical response and ponderal mass. Some tests are finally carried out, to investigate the effect of relative humidity on the optical response of this type of instruments

Gas-particle partitioning of semivolatile organic compounds (SOCs) on mixtures of aerosols in a smog chamber.

Science.gov (United States)

Chandramouli, Bharadwaj; Jang, Myoseon; Kamens, Richard M

2003-09-15

The partitioning behavior of a set of diverse SOCs on two and three component mixtures of aerosols from different sources was studied using smog chamber experimental data. A set of SOCs of different compound types was introduced into a system containing a mixture of aerosols from two or more sources. Gas and particle samples were taken using a filter-filter-denuder sampling system, and a partitioning coefficient Kp was estimated using Kp = Cp/(CgTSP). Particle size distributions were measured using a differential mobility analyzer and a light scattering detector. Gas and particle samples were analyzed using GCMS. The aerosol composition in the chamber was tracked chemically using a combination of signature compounds and the organic matter mass fraction (f(om)) of the individual aerosol sources. The physical nature of the aerosol mixture in the chamber was determined using particle size distributions, and an aggregate Kp was estimated from theoretically calculated Kp on the individual sources. Model fits for Kp showed that when the mixture involved primary sources of aerosol, the aggregate Kp of the mixture could be successfully modeled as an external mixture of the Kp on the individual aerosols. There were significant differences observed for some SOCs between modeling the system as an external and as an internal mixture. However, when one of the aerosol sources was secondary, the aggregate model Kp required incorporation of the secondary aerosol products on the preexisting aerosol for adequate model fits. Modeling such a system as an external mixture grossly overpredicted the Kp of alkanes in the mixture. Indirect evidence of heterogeneous, acid-catalyzed reactions in the particle phase was also seen, leading to a significant increase in the polarity of the resulting aerosol mix and a resulting decrease in the observed Kp of alkanes in the chamber. The model was partly consistent with this decrease but could not completely explain the reduction in Kp because of

CAIMAN: a versatile facility to produce aerosols of nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Jacoby, Jonathan; Bau, Sebastien; Witschger, Olivier, E-mail: sebastien.bau@inrs.fr [Institut National de Recherche et de Securite (INRS), Laboratoire de Metrologie des Aerosols, Rue du Morvan, CS 60027, 54519 Vandoeuvre Cedex (France)

2011-07-06

This work aims at presenting a nanoparticle generation non-transportable facility in aerosol phase called 'CAIMAN' (acronym for Characterization of Instruments Measuring Aerosols of Nanoparticles) and its performances. This facility delivers primary nanoaerosols from electrodes made of C, Al, Cu (and mixtures containing Be), Ag, Constantane (a mixture of Cu-55wt% and Ni-45wt%) particles at known concentrations, sizes, shapes and mean charge levels. It is also capable to deliver well-known particle mixture containing combinations of the 'primary' nanoaerosols and particles representatives of background aerosols (in the present work NaCl). The output of the CAIMAN facility is very consistent over long time intervals when operating under similar conditions. It indicates that repeatability is also one of the important assets of the facility.

Time dependent charging of layer clouds in the global electric circuit

Science.gov (United States)

Zhou, Limin; Tinsley, Brian A.

2012-09-01

There is much observational data consistent with the hypothesis that the ionosphere-earth current density (Jz) in the global electric circuit, which is modulated by both solar activity and thunderstorm activity, affects atmospheric dynamics and cloud cover. One candidate mechanism involves Jz causing the accumulation of space charge on droplets and aerosol particles, that affects the rate of scavenging of the latter, notably those of Cloud Condensation Nuclei (CCN) and Ice Forming Nuclei (IFN) (Tinsley, 2008, 2010). Space charge is the difference, per unit volume, between total positive and total negative electrical charge that is on droplets, aerosol particles (including the CCN and IFN) and air ions. The cumulative effects of the scavenging in stratiform clouds and aerosol layers in an air mass over the lifetime of the aerosol particles of 1-10 days affects the concentration and size distribution of the CCN, so that in subsequent episodes of cloud formation (including deep convective clouds) there can be effects on droplet size distribution, coagulation, precipitation processes, and even storm dynamics.Because the time scales for charging for some clouds can be long compared to cloud lifetimes, the amount of charge at a given time, and its effect on scavenging, depend more on the charging rate than on the equilibrium charge that would eventually be attained. To evaluate this, a new time-dependent charging model has been developed. The results show that for typical altostratus clouds with typical droplet radii 10 μm and aerosol particles of radius of 0.04 μm, the time constant for charging in response to a change in Jz is about 800 s, which is comparable to cloud formation and dissipation timescales for some cloud situations. The charging timescale is found to be strong functions of altitude and aerosol concentration, with the time constant for droplet charging at 2 km in air with a high concentration of aerosols being about an hour, and for clouds at 10 km in

Characterization of triboelectrically charged particles deposited on dielectric surfaces

Science.gov (United States)

Nesterov, A.; Löffler, F.; Cheng, Yun-Chien; Torralba, G.; König, K.; Hausmann, M.; Lindenstruth, V.; Stadler, V.; Bischoff, F. R.; Breitling, F.

2010-04-01

A device for the measurement of q/m-values and charge degradation of triboelectrically charged particles deposited on a surface was developed. The setup is based on the integration of currents, which are induced in a Faraday cage by insertion of a solid support covered with charged particles. The conductivity of different particle supports was taken into account. The 'blow-off' method, in which the particles are first deposited, and then blown off using an air stream, can be used for characterization of triboelectric properties of particles relative to different surfaces.

Characterization of triboelectrically charged particles deposited on dielectric surfaces

Energy Technology Data Exchange (ETDEWEB)

Nesterov, A; Torralba, G; Hausmann, M; Lindenstruth, V [Kirchhoff Institute of Physics, In Neuenheimer Feld 227, Heidelberg (Germany); Loeffler, F; Cheng, Yun-Chien; Koenig, K; Stadler, V; Bischoff, F R [German Cancer Research Centre, In Neuenheimer Feld 280, Heidelberg (Germany); Breitling, F, E-mail: Frank.Breitling@KIT.ed, E-mail: alexander.nesterov-mueller@kit.ed [Karlsruhe Institute of Technology (KIT), Institute for Microstructure Technology, Herrmann von Helmholtzplatz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2010-04-28

A device for the measurement of q/m-values and charge degradation of triboelectrically charged particles deposited on a surface was developed. The setup is based on the integration of currents, which are induced in a Faraday cage by insertion of a solid support covered with charged particles. The conductivity of different particle supports was taken into account. The 'blow-off' method, in which the particles are first deposited, and then blown off using an air stream, can be used for characterization of triboelectric properties of particles relative to different surfaces.

Characterization of aerosol emitted by the combustion of nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Motzkus, C; Chivas-Joly, C; Guillaume, E; Ducourtieux, S; Saragoza, L; Lesenechal, D; Mace, T, E-mail: charles.motzkus@lne.fr [LNE, 29 Avenue Roger Hennequin, 78197 Trappes Cedex (France)

2011-07-06

Day after day, new applications using nanoparticles appear in industry, increasing the probability to find these particles in the workplace as well as in ambient air. As epidemiological studies have shown an association between increased particulate air pollution and adverse health effects in susceptible members of the population, it is particularly important to characterize aerosols emitted by different sources of emission, during the combustion of composites charged with nanoparticles for example. The present study is led in the framework of the NANOFEU project, supported by the French Research Agency (ANR), in order to characterize the fire behaviour of polymers charged with suitable nanoparticles and make an alternative to retardant systems usually employed. To determine the impact of these composites on the emission of airborne particles produced during their combustions, an experimental setup has been developed to measure the mass distribution in the range of 30 nm - 10 {mu}m and the number concentration of submicrometric particles of the produced aerosol. A comparison is performed on the aerosol emitted during the combustion of several polymers alone (PMMA, PA-6), polymers containing nanofillers (silica, alumina, and carbon nanotubes) and polymers containing both nanofillers and a conventional flame retardant system (ammonium polyphosphate). The results on the morphology of particles were also investigated using AFM.

Stereotactic radiosurgery. The role of charged particles

Energy Technology Data Exchange (ETDEWEB)

Levy, R.P.; Schulte, R.W.M.; Slater, J.D.; Miller, D.W.; Slater, J.M. [Loma Linda Univ. Medical Center, CA (United States). Dept. of Radiation Medicine

1999-08-01

Stereotactic radiosurgery using charged-particle beams has been the subject of biomedical research and clinical development for more than 50 years. Charged particles of proton mass or greater manifest unique physical properties that can be used to place a high dose of radiation preferentially within the boundaries of a deeply located intracranial target volume. Since 1954, nearly 10 000 patients have been treated using this technique. Treated disorders include pituitary tumors, vascular malformations, primary and metastatic brain tumors, and subfoveal neovascularization. Charged-particle radiosurgery is particularly advantageous for the conformal treatment of large and/or irregularly shaped lesions, or for the treatment of lesions located in front of or adjacent to sensitive brain structures. (orig.)

Stereotactic radiosurgery. The role of charged particles

International Nuclear Information System (INIS)

Levy, R.P.; Schulte, R.W.M.; Slater, J.D.; Miller, D.W.; Slater, J.M.

1999-01-01

Stereotactic radiosurgery using charged-particle beams has been the subject of biomedical research and clinical development for more than 50 years. Charged particles of proton mass or greater manifest unique physical properties that can be used to place a high dose of radiation preferentially within the boundaries of a deeply located intracranial target volume. Since 1954, nearly 10 000 patients have been treated using this technique. Treated disorders include pituitary tumors, vascular malformations, primary and metastatic brain tumors, and subfoveal neovascularization. Charged-particle radiosurgery is particularly advantageous for the conformal treatment of large and/or irregularly shaped lesions, or for the treatment of lesions located in front of or adjacent to sensitive brain structures. (orig.)

Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

Energy Technology Data Exchange (ETDEWEB)

Rissler, Jenny; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology

2005-02-01

This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K{sub 2}SO{sub 4}, and K{sub 2}CO{sub 3}). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be {approx}2.5.

Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

International Nuclear Information System (INIS)

Rissler, Jenny; Swietlicki, Erik; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats; Strand, Michael; Lillieblad, Lena; Sanati, Mehri

2005-01-01

This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K 2 SO 4 , and K 2 CO 3 ). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be ∼2.5

Mechanism and Kinetics of the Formation and Transport of Aerosol Particles in the Lower Stratosphere

Science.gov (United States)

Aloyan, A. E.; Ermakov, A. N.; Arutyunyan, V. O.

2018-03-01

Field and laboratory observation data on aerosol particles in the lower stratosphere are considered. The microphysics of their formation, mechanisms of heterogeneous chemical reactions involving reservoir gases (e.g., HCl, ClONO2, etc.) and their kinetic characteristics are analyzed. A new model of global transport of gaseous and aerosol admixtures in the lower stratosphere is described. The preliminary results from a numerical simulation of the formation of sulfate particles of the Junge layer and particles of polar stratospheric clouds (PSCs, types Ia, Ib, and II) are presented, and their effect on the gas and aerosol composition is analyzed.

Electro-optical detection of charged particles

International Nuclear Information System (INIS)

Semertzidis, Y.K.; Castillo, V.; Kowalski, L.; Kraus, D.E.; Larsen, R.; Lazarus, D.M.; Magurno, B.; Nikas, D.; Ozben, C.; Srinivasan-Rao, T.; Tsang, T.

2000-01-01

We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO 3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams

Electro-optical detection of charged particles

CERN Document Server

Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R; Lazarus, D M; Magurno, B; Nikas, D; Ozben, C; Srinivasan-Rao, T; Tsang, Thomas

2000-01-01

We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO sub 3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

Electro-optical detection of charged particles

Energy Technology Data Exchange (ETDEWEB)

Semertzidis, Y.K.; Castillo, V.; Kowalski, L.; Kraus, D.E.; Larsen, R.; Lazarus, D.M. E-mail: lazarus@sun2.bnl.gov; Magurno, B.; Nikas, D.; Ozben, C.; Srinivasan-Rao, T.; Tsang, T

2000-10-01

We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO{sub 3} crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

Study of Cl containing urban aerosol particles by ion beam analytical methods

International Nuclear Information System (INIS)

Angyal, A.; Kertesz, Zs.; Szikszai, Z.; Szoboszlai, T.

2009-01-01

Complete text of publication follows. In the densely populated areas of Europe one of the most important environmental problems is aerosol pollution. Thus one of the main goals of atmospheric research is to determine aerosol sources. In order to identify the origin of the particles, the knowledge of the chemical composition and size distribution is demanded. As a result of a source apportionment study, several sources of fine (particles with aerodynamic diameter < 2.5 μm) and coarse (10 μm ≥ aerodynamic diameter ≥ 2.5 μm) urban particulate matter were identified in Debrecen, using the hourly evolution of the elemental components. Sources characterized by high chlorine content were found in both size fractions, which gave significant contribution to the aerosol concentration in Debrecen. However, the origin of these particles could not be identified on the available information. In this work we give a more accurate characterization of the sources of coarse-mode Cl by using single particle analysis. Aerosol samples with 2-3 hours time resolution were collected in the frame of sampling campaigns in the garden of ATOMKI between October 2007 and January 2009. The elemental composition (for Z ≥ 13) was determined by Particle Induced X-ray Emission (PIXE). Single particle analysis of chosen samples was done on the ATOMKI Scanning Nuclear Microprobe Facility. Morphology, size and elemental composition for Z ≥ 6 of around 1000 coarse mode particles were determined by Scanning Transmission Ion Microscopy, light element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the data set to group the particles. In order to determine the possible sources of Cl in the coarse mode, the correlation between Cl and other elements, which could be used as tracers of different sources, was examined. Cl showed very strong correlation with Na. However the Cl:Na ratio was found to be different for different episodes indicating different origin of these

Charged particle beams

CERN Document Server

Humphries, Stanley

2013-01-01

Detailed enough for a text and sufficiently comprehensive for a reference, this volume addresses topics vital to understanding high-power accelerators and high-brightness-charged particle beams. Subjects include stochastic cooling, high-brightness injectors, and the free electron laser. Humphries provides students with the critical skills necessary for the problem-solving insights unique to collective physics problems. 1990 edition.

Geometrical charged-particle optics

CERN Document Server

Rose, Harald

2012-01-01

This second edition is an extended version of the first edition of Geometrical Charged-Particle Optics. The updated reference monograph is intended as a guide for researchers and graduate students who are seeking a comprehensive treatment of the design of instruments and beam-guiding systems of charged particles and their propagation in electromagnetic fields. Wave aspects are included in this edition for explaining electron holography, the Aharanov-Bohm effect and the resolution of electron microscopes limited by diffraction. Several methods for calculating the electromagnetic field are presented and procedures are outlined for calculating the properties of systems with arbitrarily curved axis. Detailed methods are presented for designing and optimizing special components such as aberration correctors, spectrometers, energy filters monochromators, ion traps, electron mirrors and cathode lenses. In particular, the optics of rotationally symmetric lenses, quadrupoles, and systems composed of these elements are...

Heavy-ion radiography applied to charged particle radiotherapy

International Nuclear Information System (INIS)

Chen, G.T.Y.; Fabrikant, J.I.; Holley, W.R.; Tobias, C.A.; Castro, J.R.

1980-01-01

The objectives of the heavy-ion radiography research program applied to the clinical cancer research program of charged particle radiotherapy have a twofold purpose: (1) to explore the manner in which heavy-ion radiography and CT reconstruction can provide improved tumor localization, treatment planning, and beam delivery for radiotherapy with accelerated heavy charged particles; and (2) to explore the usefulness of heavy-ion radiography in detecting, localizing, and sizing soft tissue cancers in the human body. The techniques and procedures developed for heavy-ion radiography should prove successful in support of charged particle radiotherapy

Leading charged particle correlations at ALICE

CERN Document Server

Krizek, F

2012-01-01

A leading charged particle correlation analysis was performed on p + p data measured by the ALICE experiment at √s = 7 TeV. The main emphasis was on the xE distributions for a given charged hadron trigger momentum pTt. It was observed that dN/dxE is driven by the imbalance function at low xE. At high xE it shows exponential behavior and the extracted slope can be related to hzti of the trigger particle.

Gravitational instantons as models for charged particle systems

Science.gov (United States)

Franchetti, Guido; Manton, Nicholas S.

2013-03-01

In this paper we propose ALF gravitational instantons of types A k and D k as models for charged particle systems. We calculate the charges of the two families. These are -( k + 1) for A k , which is proposed as a model for k + 1 electrons, and 2 - k for D k , which is proposed as a model for either a particle of charge +2 and k electrons or a proton and k - 1 electrons. Making use of preferred topological and metrical structures of the manifolds, namely metrically preferred representatives of middle dimension homology classes, we construct two different energy functionals which reproduce the Coulomb interaction energy for a system of charged particles.

Toward Quantifying the Mass-Based Hygroscopicity of Individual Submicron Atmospheric Aerosol Particles with STXM/NEXAFS and SEM/EDX

Science.gov (United States)

Yancey Piens, D.; Kelly, S. T.; OBrien, R. E.; Wang, B.; Petters, M. D.; Laskin, A.; Gilles, M. K.

2014-12-01

The hygroscopic behavior of atmospheric aerosols influences their optical and cloud-nucleation properties, and therefore affects climate. Although changes in particle size as a function of relative humidity have often been used to quantify the hygroscopic behavior of submicron aerosol particles, it has been noted that calculations of hygroscopicity based on size contain error due to particle porosity, non-ideal volume additivity and changes in surface tension. We will present a method to quantify the hygroscopic behavior of submicron aerosol particles based on changes in mass, rather than size, as a function of relative humidity. This method results from a novel experimental approach combining scanning transmission x-ray microscopy with near-edge x-ray absorption fine spectroscopy (STXM/NEXAFS), as well as scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDX) on the same individual particles. First, using STXM/NEXAFS, our methods are applied to aerosol particles of known composition ‒ for instance ammonium sulfate, sodium bromide and levoglucosan ‒ and validated by theory. Then, using STXM/NEXAFS and SEM/EDX, these methods are extended to mixed atmospheric aerosol particles collected in the field at the DOE Atmospheric Radiation Measurement (ARM) Climate Research Facility at the Southern Great Planes sampling site in Oklahoma, USA. We have observed and quantified a range of hygroscopic behaviors which are correlated to the composition and morphology of individual aerosol particles. These methods will have implications for parameterizing aerosol mixing state and cloud-nucleation activity in atmospheric models.

On the secondary charging effects and structure of mesospheric dust particles impacting on rocket probes

Directory of Open Access Journals (Sweden)

O. Havnes

2007-03-01

Full Text Available The dust probe DUSTY, first launched during the summer of 1994 (flights ECT–02 and ECT–07 from Andøya Rocket Range, northern Norway, was the first probe to unambiguously detect heavy charged mesospheric aerosols, from hereon referred to as dust. In ECT–02 the probe detected negatively charged dust particles in the height interval of 83 to 88.5 km. In this flight, the lower grid in the detector (Grid 2 measures both positive and negative currents in various regions, and we find that the relationship between the current measurements of Grid 2 and the bottom plate can only be explained by influence from secondary charge production on Grid 2. In ECT–07, which had a large coning, positive currents reaching the top grid of the probe were interpreted as due to the impact of positively charged dust particles. We have now reanalyzed the data from ECT–07 and arrived at the conclusion that the measured positive currents to this grid must have been mainly due to secondary charging effects from the impacting dust particles. The grid consists of a set of parallel wires crossed with an identical set of wires on top of it, and we find that if the observed currents were created from the direct impact of charged dust particles, then they should be very weakly modulated at four times the rocket spin rate ω_R. Observations show, however, that the observed currents are strongly modulated at 2ω_R. We cannot reproduce the observed large modulations of the impact currents in the dust layer if the currents are due only to the transfer of the charges on the impacted dust particles. Based on the results of recent ice cluster impact secondary charging experiments by Tomsic (2003, which found that a small fraction of the ice clusters, when impacting with nearly grazing incidence, carried away one negative charge −1e, we have arrived at the conclusion that similar, but significantly more effective, charging effects must

Hygroscopic properties of smoke-generated organic aerosol particles emitted in the marine atmosphere

Directory of Open Access Journals (Sweden)

A. Wonaschütz

2013-10-01

Full Text Available During the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE, a plume of organic aerosol was produced by a smoke generator and emitted into the marine atmosphere from aboard the R/V Point Sur. In this study, the hygroscopic properties and the chemical composition of the plume were studied at plume ages between 0 and 4 h in different meteorological conditions. In sunny conditions, the plume particles had very low hygroscopic growth factors (GFs: between 1.05 and 1.09 for 30 nm and between 1.02 and 1.1 for 150 nm dry size at a relative humidity (RH of 92%, contrasted by an average marine background GF of 1.6. New particles were produced in large quantities (several 10 000 cm−3, which lead to substantially increased cloud condensation nuclei (CCN concentrations at supersaturations between 0.07 and 0.88%. Ratios of oxygen to carbon (O : C and water-soluble organic mass (WSOM increased with plume age: from −3, respectively, while organic mass fractions decreased slightly (~ 0.97 to ~ 0.94. High-resolution aerosol mass spectrometer (AMS spectra show that the organic fragment m/z 43 was dominated by C2H3O+ in the small, new particle mode and by C3H7+ in the large particle mode. In the marine background aerosol, GFs for 150 nm particles at 40% RH were found to be enhanced at higher organic mass fractions: an average GF of 1.06 was observed for aerosols with an organic mass fraction of 0.53, and a GF of 1.04 for an organic mass fraction of 0.35.

Quantification of bitumen particles in aerosol and soil samples using HP-GPC

DEFF Research Database (Denmark)

Fauser, Patrik; Tjell, Jens Christian; Mosbæk, Hans

2000-01-01

A method for identifying and quantifying bitumen particles, generated from the wear of roadway asphalts, in aerosol and soil samples has been developed. Bitumen is found to be the only contributor to airborne particles containing organic molecules with molecular weights larger than 2000 g pr. mol....... These are separated and identified using High Performance Gel Permeation Chromatography (HP-GPC) with fluorescence detection. As an additional detection method Infra Red spectrometry (IR) is employed for selected samples. The methods have been used on aerosol, soil and other samples....

Modeling Dry Deposition of Aerosol Particles on Rough Surfaces

Czech Academy of Sciences Publication Activity Database

Hussein, T.; Smolík, Jiří; Kerminen, V.-M.; Kulmala, M.

2012-01-01

Roč. 46, č. 1 (2012), s. 44-59 ISSN 0278-6826 Institutional research plan: CEZ:AV0Z40720504 Keywords : aerosol particles * dry deposition * transport Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.780, year: 2012

Charged-particle calculations using Boltzmann transport methods

International Nuclear Information System (INIS)

Hoffman, T.J.; Dodds, H.L. Jr.; Robinson, M.T.; Holmes, D.K.

1981-01-01

Several aspects of radiation damage effects in fusion reactor neutron and ion irradiation environments are amenable to treatment by transport theory methods. In this paper, multigroup transport techniques are developed for the calculation of charged particle range distributions, reflection coefficients, and sputtering yields. The Boltzmann transport approach can be implemented, with minor changes, in standard neutral particle computer codes. With the multigroup discrete ordinates code, ANISN, determination of ion and target atom distributions as functions of position, energy, and direction can be obtained without the stochastic error associated with atomistic computer codes such as MARLOWE and TRIM. With the multigroup Monte Carlo code, MORSE, charged particle effects can be obtained for problems associated with very complex geometries. Results are presented for several charged particle problems. Good agreement is obtained between quantities calculated with the multigroup approach and those obtained experimentally or by atomistic computer codes

Ice cloud processing of ultra-viscous/glassy aerosol particles leads to enhanced ice nucleation ability

Directory of Open Access Journals (Sweden)

R. Wagner

2012-09-01

Full Text Available The ice nucleation potential of airborne glassy aqueous aerosol particles has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 247 and 216 K. Four different solutes were used as proxies for oxygenated organic matter found in the atmosphere: raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA, levoglucosan, and a multi-component mixture of raffinose with five dicarboxylic acids and ammonium sulphate. Similar to previous experiments with citric acid aerosols, all particles were found to nucleate ice heterogeneously before reaching the homogeneous freezing threshold provided that the freezing cycles were started well below the respective glass transition temperatures of the compounds; this is discussed in detail in a separate article. In this contribution, we identify a further mechanism by which glassy aerosols can promote ice nucleation below the homogeneous freezing limit. If the glassy aerosol particles are probed in freezing cycles started only a few degrees below their respective glass transition temperatures, they enter the liquid regime of the state diagram upon increasing relative humidity (moisture-induced glass-to-liquid transition before being able to act as heterogeneous ice nuclei. Ice formation then only occurs by homogeneous freezing at elevated supersaturation levels. When ice forms the remaining solution freeze concentrates and re-vitrifies. If these ice cloud processed glassy aerosol particles are then probed in a second freezing cycle at the same temperature, they catalyse ice formation at a supersaturation threshold between 5 and 30% with respect to ice. By analogy with the enhanced ice nucleation ability of insoluble ice nuclei like mineral dusts after they nucleate ice once, we refer to this phenomenon as pre-activation. We propose a number of possible explanations for why glassy aerosol particles that have re

Chamber for Aerosol Deposition of Bioparticles

Science.gov (United States)

Kern, Roger; Kirschner, Larry

2008-01-01

Laboratory apparatus is depicted that is a chamber for aerosol deposition of bioparticles on surfaces of test coupons. It is designed for primary use in inoculating both flat and three-dimensional objects with approximately reproducible, uniform dispersions of bacterial spores of the genus Bacillus so that the objects could be used as standards for removal of the spores by quantitative surface sampling and/or cleaning processes. The apparatus is also designed for deposition of particles other than bacterial spores, including fungal spores, viruses, bacteriophages, and standard micron-sized beads. The novelty of the apparatus lies in the combination of a controllable nebulization system with a settling chamber large enough to contain a significant number of test coupons. Several companies market other nebulizer systems, but none are known to include chambers for deposition of bioparticles to mimic the natural fallout of bioparticles. The nebulization system is an expanded and improved version of commercially available aerosol generators that include nebulizers and drying columns. In comparison with a typical commercial aerosol generator, this system includes additional, higher-resolution flowmeters and an additional pressure regulator. Also, unlike a typical commercial aerosol generator, it includes stopcocks for separately controlling flows of gases to the nebulizer and drying column. To maximize the degree of uniformity of dispersion of bioaerosol, the chamber is shaped as an axisymmetrical cylinder and the aerosol generator is positioned centrally within the chamber and aimed upward like a fountain. In order to minimize electric charge associated with the aerosol particles, the drying column is made of aluminum, the drying column is in direct contact with an aluminum base plate, and three equally spaced Po-210 antistatic strips are located at the exit end of the drying column. The sides and top of the chamber are made of an acrylic polymer; to prevent

Size distribution and hygroscopic properties of aerosol particles from dry-season biomass burning in Amazonia

Directory of Open Access Journals (Sweden)

J. Rissler

2006-01-01

Full Text Available Aerosol particle number size distributions and hygroscopic properties were measured at a pasture site in the southwestern Amazon region (Rondonia. The measurements were performed 11 September-14 November 2002 as part of LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate, and cover the later part of the dry season (with heavy biomass burning, a transition period, and the onset of the wet period. Particle number size distributions were measured with a DMPS (Differential Mobility Particle Sizer, 3-850nm and an APS (Aerodynamic Particle Sizer, extending the distributions up to 3.3 µm in diameter. An H-TDMA (Hygroscopic Tandem Differential Mobility Analyzer measured the hygroscopic diameter growth factors (Gf at 90% relative humidity (RH, for particles with dry diameters (dp between 20-440 nm, and at several occasions RH scans (30-90% RH were performed for 165nm particles. These data provide the most extensive characterization of Amazonian biomass burning aerosol, with respect to particle number size distributions and hygroscopic properties, presented until now. The evolution of the convective boundary layer over the course of the day causes a distinct diel variation in the aerosol physical properties, which was used to get information about the properties of the aerosol at higher altitudes. The number size distributions averaged over the three defined time periods showed three modes; a nucleation mode with geometrical median diameters (GMD of ~12 nm, an Aitken mode (GMD=61-92 nm and an accumulation mode (GMD=128-190 nm. The two larger modes were shifted towards larger GMD with increasing influence from biomass burning. The hygroscopic growth at 90% RH revealed a somewhat external mixture with two groups of particles; here denoted nearly hydrophobic (Gf~1.09 for 100 nm particles and moderately hygroscopic (Gf~1.26. While the hygroscopic growth factors were surprisingly similar over the

The penetration of fibrous media by aerosols as a function of particle size

Energy Technology Data Exchange (ETDEWEB)

Dyment, J.

1963-11-15

This paper is concerned with the accurate experimental determination of the penetration of fibrous filter media by aerosols as a function of particle size, a topic about which previous papers give partial and conflicting data. in the present work, a heterogeneous sodium chloride aerosol was sampled before and after passing through the glass fiber filter medium by means of an electrostatic precipitator and the samples were examined under the electron microscope; the relation between particle size and penetration was derives at different gas velocities by comparison of the size distribution of the filtered and unfiltered clouds. As an extension of this work, size analyses have been made of plutonium aerosols occurring in glove boxes and enclosures during typical working operations. This information is considered in relation to the penetration of plutonium and other high density aerosol materials through filters. (auth)

Characterization of four different bipolar charging devices for nanoparticle charge conditioning

International Nuclear Information System (INIS)

Kallinger, Peter; Steiner, Gerhard; Szymanski, Wladyslaw W.

2012-01-01

Well-defined charge conditioning of nanoparticles is a prerequisite for a number of particle measuring techniques. We investigated two different soft X-ray devices (custom-built and TSI advanced aerosol neutralizer) an AC-corona discharge device (MSP electrical ionizer) and a radioactivity based Am-241 charger as a reference. Electrical mobility size distributions of positive and negative ions created in all devices were determined and their applicability for particle charging examined. The mobility spectra of the positive ions were found to be quite comparable for all chargers with a mean mobility of 1.50–1.60 cm 2 V −1 s −1 , whereas the spectra of the negative ions show differences in morphology leading to a broader range of mean mobilities (1.68–2.09 cm 2 V −1 s −1 ). However, results confirm that under the selected experimental conditions the charge equilibrium related to bipolar diffusion charging process was obtained in all charging devices.

Cassini CAPS-ELS observations of carbon-based anions and aerosol growth in Titan's ionosphere

Science.gov (United States)

Desai, Ravindra; Coates, Andrew; Wellbrock, Anne; Kataria, Dhiren; Jones, Geraint; Lewis, Gethyn; Waite, J.

2016-06-01

Cassini observations of Titans ionosphere revealed an atmosphere rich in positively charged ions with masses up to > 350 amu and negatively charged ions and aerosols with mass over charge ratios as high as 13,800 amu/q. The detection of negatively charged molecules by the Cassini CAPS Electron Spectrometer (CAPS-ELS) was particularly surprising and showed how the synthesis of large aerosol-size particles takes place at altitudes much greater than previously thought. Here, we present further analysis into this CAPS-ELS dataset, through an enhanced understanding of the instrument's response function. In previous studies the intrinsic E/E energy resolution of the instrument did not allow specific species to be identified and the detections were classified into broad mass ranges. In this study we use an updated fitting procedure to show how the ELS mass spectrum can be resolved into specific peaks at multiples of carbon-based anions up to > 100 amu/q. The negatively charged ions and aerosols in Titans ionosphere increase in mass with decreasing altitude, the lightest species being observed close to Titan's exobase of ˜1,450km and heaviest species observed at altitudes < 950km. We identify key stages in this apparent growth process and report on key intermediaries which appear to trigger the rapid growth of the larger aerosol-size particles.

Charged-particle spectroscopy in organic semiconducting single crystals

Energy Technology Data Exchange (ETDEWEB)

Ciavatti, A.; Basiricò, L.; Fraboni, B. [Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); Sellin, P. J. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Fraleoni-Morgera, A. [ELETTRA-Sincrotrone Trieste, Strada Statale 14, Km 163.5, Basovizza, Trieste (Italy); Department of Engineering and Architecture, University of Trieste, V. Valerio 10, 34100 Trieste (Italy); CNR-Nano S3 Institute, Via Campi 213/A, 41125 Modena (Italy)

2016-04-11

The use of organic materials as radiation detectors has grown, due to the easy processability in liquid phase at room temperature and the possibility to cover large areas by means of low cost deposition techniques. Direct charged-particle detectors based on solution-grown Organic Semiconducting Single Crystals (OSSCs) are shown to be capable to detect charged particles in pulse mode, with very good peak discrimination. The direct charged-particle detection in OSSCs has been assessed both in the planar and in the vertical axes, and a digital pulse processing algorithm has been used to perform pulse height spectroscopy and to study the charge collection efficiency as a function of the applied bias voltage. Taking advantage of the charge spectroscopy and the good peak discrimination of pulse height spectra, an Hecht-like behavior of OSSCs radiation detectors is demonstrated. It has been possible to estimate the mobility-lifetime value in organic materials, a fundamental parameter for the characterization of radiation detectors, whose results are equal to μτ{sub coplanar} = (5 .5 ± 0.6 ) × 10{sup −6} cm{sup 2}/V and μτ{sub sandwich} = (1 .9 ± 0.2 ) × 10{sup −6} cm{sup 2}/V, values comparable to those of polycrystalline inorganic detectors. Moreover, alpha particles Time-of-Flight experiments have been carried out to estimate the drift mobility value. The results reported here indicate how charged-particle detectors based on OSSCs possess a great potential as low-cost, large area, solid-state direct detectors operating at room temperature. More interestingly, the good detection efficiency and peak discrimination observed for charged-particle detection in organic materials (hydrogen-rich molecules) are encouraging for their further exploitation in the detection of thermal and high-energy neutrons.

In-situ observations of interstitial aerosol particles and cloud residues found in contrails

Energy Technology Data Exchange (ETDEWEB)

Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

1997-12-31

In spring 1994 a series of flights were conducted in cirrus clouds and contrails over southern Germany. One of the aims of this campaign was to study the phase partitioning of aerosols and water in these clouds. To achieve this separation of particles two complementary sampling probes were mounted on the research aircraft Falcon. These are the Counterflow Virtual Impactor (CVI) or super-micrometer inlet, and the interstitial inlet or submicrometer inlet. The CVI is a device that inertially separates cloud elements larger than a certain aerodynamic size from the surrounding atmosphere into a warm, dry and particle free air. Assuming that each cloud element leaves behind only one residue particle, these measurements yield an equivalent number concentration for cloud particles having an aerodynamic diameter larger than the lower cut size of the CVI. The size distribution of the sampled aerosol and residual particles between 0.1 to 3.5 {mu}m diameter was measured by a PMS PCASP (Passive Cavity Aerosol Spectrometer) working alternatively on both inlets. The gas-phase water vapor content was measured by a cryogenic frost point mirror. (R.P.) 4 refs.

In-situ observations of interstitial aerosol particles and cloud residues found in contrails

Energy Technology Data Exchange (ETDEWEB)

Stroem, J [Stockholm Univ. (Sweden). Dept. of Meteorology

1998-12-31

In spring 1994 a series of flights were conducted in cirrus clouds and contrails over southern Germany. One of the aims of this campaign was to study the phase partitioning of aerosols and water in these clouds. To achieve this separation of particles two complementary sampling probes were mounted on the research aircraft Falcon. These are the Counterflow Virtual Impactor (CVI) or super-micrometer inlet, and the interstitial inlet or submicrometer inlet. The CVI is a device that inertially separates cloud elements larger than a certain aerodynamic size from the surrounding atmosphere into a warm, dry and particle free air. Assuming that each cloud element leaves behind only one residue particle, these measurements yield an equivalent number concentration for cloud particles having an aerodynamic diameter larger than the lower cut size of the CVI. The size distribution of the sampled aerosol and residual particles between 0.1 to 3.5 {mu}m diameter was measured by a PMS PCASP (Passive Cavity Aerosol Spectrometer) working alternatively on both inlets. The gas-phase water vapor content was measured by a cryogenic frost point mirror. (R.P.) 4 refs.

Late time CMB anisotropies constrain mini-charged particles

Energy Technology Data Exchange (ETDEWEB)

Burrage, C.; Redondo, J.; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Jaeckel, J. [Univ. of Durham, Inst. for Particle Physics Phenomenology (United Kingdom)

2009-09-15

Observations of the temperature anisotropies induced as light from the CMB passes through large scale structures in the late universe are a sensitive probe of the interactions of photons in such environments. In extensions of the Standard Model which give rise to mini-charged particles, photons propagating through transverse magnetic fields can be lost to pair production of such particles. Such a decrement in the photon flux would occur as photons from the CMB traverse the magnetic fields of galaxy clusters. Therefore late time CMB anisotropies can be used to constrain the properties of mini- charged particles. We outline how this test is constructed, and present new constraints on mini-charged particles from observations of the Sunyaev-Zel'dovich effect in the Coma cluster. (orig.)

Electro-optical Detection of Charged Particles

International Nuclear Information System (INIS)

Lazarus, D.M.

2001-01-01

The electric field of charged particles can induce transient changes in the polarization of light that produce sub-picosecond modulation of a laser beam. This is a consequence of the electro-optical effect in which the presence of the electric field in an electro-optical medium produces a change in the index of refraction of the medium resulting in a phase retardation between polarization components parallel and perpendicular to the electric field. We have observed the electro-optical effect due to 10 picosecond electron beam bunches with rise times that were limited by the bandwidth of our data acquisition system. This technology is being applied to particle beam diagnostics and has the potential to produce charged particle detectors combining excellent spatial resolution with unprecedented temporal precision.

Identification of sources of aerosol particles in three locations in eastern Botswana

Science.gov (United States)

Chimidza, S.; Moloi, K.

2000-07-01

Airborne particles have been collected using a dichotomous virtual impactor at three different locations in the eastern part of Botswana: Serowe, Selibe-Phikwe, and Francistown. The particles were separated into two fractions (fine and coarse). Sampling at the three locations was done consecutively during the months of July and August, which are usually dry and stable. The sampling time for each sample was 12 hours during the day. For elemental composition, energy-dispersive x-ray fluorescence technique was used. Correlations and principal component analysis with varimax rotation were used to identify major sources of aerosol particles. In all the three places, soil was found to be the main source of aerosol particles. A copper-nickel mine and smelter at Selibe-Phikwe was found to be not only a source of copper and nickel particles in Selibe-Phikwe but also a source of these particles in far places like Serowe. In Selibe-Phikwe and Francistown, car exhaust was found to be the major source of fine particles of lead and bromine.

Transmutation doping of semiconductors by charged particles (review)

International Nuclear Information System (INIS)

Kozlovskii, V.V.; Zakharenkov, L.F.; Shustrov, B.A.

1992-01-01

A review is given of the state of the art in one of the current topics in radiation doping of semiconductors, which is process of nuclear transmutation doping (NTD) charged particles. In contrast to the neutron and photonuclear transmutation doping, which have been dealt with in monographs and reviews, NTD caused by the action of charged particles is a subject growing very rapidly in the last 10-15 years, but still lacking systematic accounts. The review consists of three sections. The first section deals with the characteristics of nuclear reactions in semiconductors caused by the action of charged particles: the main stress is on the modeling of NTD processes in semiconductors under the action of charged particles. An analysis is made of the modeling intended to give the total numbers of donors and acceptor impurities introduced by the NTD process, to optimize the compensation coefficients, and to estimate the distributions of the dopants with depth in a semiconductor crystal. In the second section the state of the art of experimental investigations of NTD under the influence of charged particles is considered. In view of the specific objects that have been investigated experimntally, the second section is divided into three subsections: silicon, III-V compounds, other semiconductors and related materials (such as high-temperature superconductors, ferroelectric films, etc.). An analysis is made of the communications reporting experimental data on the total numbers of dopants which are introduced, concentration of the electrically active fraction of the impurity, profiles of the dopant distributions, and conditions for efficient annealing of radiation defects. The third section deals with the suitability of NTD by charged particles for the fabrication of semiconductor devices. 45 refs

Radon decay products and 10-1100 nm aerosol particles in Postojna Cave

Science.gov (United States)

Bezek, M.; Gregorič, A.; Vaupotič, J.

2013-03-01

At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn) decay products and the number concentration and size distribution of aerosol particles in the size range of 10-1100 nm were monitored, with the focus on the unattached fraction (fun) of radon decay products (RnDPs), a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm-3) than in winter (2800 cm-3), and was dominated by 50 nm particles (related to the attached RnDPs) in winter. This explains the higher fun values in summer (0.75) and the lower winter measurement (0.04) and, consequently, DCFD values of 43.6 and 13.1 mSv WLM-1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

Charged particle in higher dimensional weakly charged rotating black hole spacetime

International Nuclear Information System (INIS)

Frolov, Valeri P.; Krtous, Pavel

2011-01-01

We study charged particle motion in weakly charged higher dimensional black holes. To describe the electromagnetic field we use a test field approximation and the higher dimensional Kerr-NUT-(A)dS metric as a background geometry. It is shown that for a special configuration of the electromagnetic field, the equations of motion of charged particles are completely integrable. The vector potential of such a field is proportional to one of the Killing vectors (called a primary Killing vector) from the 'Killing tower' of symmetry generating objects which exists in the background geometry. A free constant in the definition of the adopted electromagnetic potential is proportional to the electric charge of the higher dimensional black hole. The full set of independent conserved quantities in involution is found. We demonstrate that Hamilton-Jacobi equations are separable, as is the corresponding Klein-Gordon equation and its symmetry operators.

TEM investigations of microstructures of combustion aerosols

International Nuclear Information System (INIS)

Marquardt, A.; Hackfort, H.; Borchardt, J.; Schober, T.; Friedrich, J.

1992-12-01

In the incineration of organic material, apart from a series of gaseous pollutants, particulate pollutants or combustion aerosols also arise. The latter frequently consist of particles with a solid core of carbon to which a large number of inorganic and organic compounds are attached. These primarily include the polycyclic aromatic hydrocarbons (PAH) and their nitro-derivatives (NPAH), whose mutagenic or carcinogenic effect is known. The invisible particle sizes in the nanometer range, whose retention in the incineration off-gas is not state of the art, are of increasing significance for man and environment. On the one hand, they are deposited almost completely in the human lung. On the other hand, due to their fine dispersity they have along residence time in the atmosphere where they participate in chemical reactions and climatically significant processes. Important insights about the formation process of combustion aerosols are to be expected from the imaging of their microstructures in the transmission electron microscope (TEM). The present contribution describes the development and application of a representative sampling procedure for aerosols from a partial flow of flue gas from a fluidized-bed furnace. The method developed consists of electrically charging aerosol particles in situ and subsequently selectively precipitating them onto a microscope slide in an electric field. TEM studies of aerosol microstructures on the microscope slides revealed that in the combustion of petrol and heating oil under different combustion conditions in principle the same particle structures result, whereas in the incineration of used lubricating oil quite different particle structures were found. Results from the literature on aerosol microstructures in exhaust gases from petrol and diesel engines demonstrate agreement with the results of this study in the basic structure of the particles. (orig.) [de

Bibliography of integral charged-particle nuclear data

International Nuclear Information System (INIS)

Burrows, T.W.; Wyant, G.

1981-03-01

This publication is the first supplement to the archival edition of the National Nuclear Data Center's charged-particle bibliography. This supplement contains citations to all references scanned since March 15, 1980, and all corrections and additions to previous citations, and indexes all data received in the international exchanged format (EXFOR). The primary goal of the bibliography has been to satisfy the need expressed by the Nuclear Reaction Data Center Network for a concise and comprehensive bibliography of integral charged-particle cross section data and to provide an index of data exchanged among the members. As a result of a recommendation by the recent Workshop on Intense High Energy Neutron Source and Their Characteristics, we have also undertaken to expand the coverage of charged-particle-induced neutron-source reactions to include differential data. This supplement is divided into two sections, References and Isotope Production. The References section contains all references satisfying the criteria noted. The Isotope Production section contains an abbreviated reference line for all entries which contain information on a definite residual nucleus, on particle production, or on mass, charge, or isotopic distributions. Entries in the References section are sequentially numbered. These sequence numbers serve as a link between the two sections

Medium-energy charged-particle data for evaluation

International Nuclear Information System (INIS)

Pearlstein, S.

1989-01-01

Medium-energy charged particles incident on targets can cause a variety of nuclear reactions. Charged-particle transport calculations require access to a large body of cross-section data, which results in interest in an evaluated charged-particle data library. Developing an evaluated data library can involve several steps. An index to the literature on measurements and theory is useful to locate information relevant to data evaluation. A computerized compilation of measurements facilitates the intercomparison of different experiments and the determination of how well data are known. Nuclear models, based on theory or phenomenological evidence, are compared with experiment and, where validated, are used to fill in regions where experimental data are not available. Finally, the selected data are placed into computer-readable formats for use in transport calculations. Specialized indexes to bibliography help the scientist to keep up with his field and catch up with new subjects of interest. Several indexes are relevant to medium-energy nuclear data. In addition, these data are covered in several reports not issued on a regular basis. The technical area of medium-energy charged-particle data is maturing. From isolated measurements and theories, a comprehensive approach toward establishing a validated data base extending from low to high energies is emerging

XPS and EPXMA investigation and chemical speciation of aerosol samples formed in LWR core melting experiments

International Nuclear Information System (INIS)

Moers, H.; Jenett, H.; Kaufmann, R.; Klewe-Nebenius, H.; Pfennig, G.; Ache, H.J.

1985-09-01

Aerosol samples consisting of fission products and elements of light water reactor structural materials were collected during simulating in a laboratory scale the heat-up phase of a core melt accident. The aerosol particles were formed in a steam atmosphere at temperatures between 1200 and 1900 0 C of the melting charge. The investigation of the samples by use of X-ray photoelectron spectroscopy (XPS) permitted the chemical speciation of the detected aerosol constituents silver, cadmium, indium, tellurium, iodine, and cesium. A comparison of the elemental analysis results obtained from XPS with those achieved from electron probe X-ray micro analysis (EPXMA) revealed that aerosol particle surface and aerosol particle bulk are principally composed of the same elements and that these compositions vary with release temperature. In addition, quantitative differences between the composition of surface and bulk have only been observed for those aerosol samples which were collected at higher melting charge temperatures. In order to obtain direct information on chemical species below the surface selected samples were argon ion bombarded. Changes in composition and chemistry were monitored by XPS, and the results were interpreted in light of the effects, which were observed when appropriate standard samples were sputtered. (orig.) [de

Stable Carbon Fractionation In Size Segregated Aerosol Particles Produced By Controlled Biomass Burning

Science.gov (United States)

Masalaite, Agne; Garbaras, Andrius; Garbariene, Inga; Ceburnis, Darius; Martuzevicius, Dainius; Puida, Egidijus; Kvietkus, Kestutis; Remeikis, Vidmantas

2014-05-01

Biomass burning is the largest source of primary fine fraction carbonaceous particles and the second largest source of trace gases in the global atmosphere with a strong effect not only on the regional scale but also in areas distant from the source . Many studies have often assumed no significant carbon isotope fractionation occurring between black carbon and the original vegetation during combustion. However, other studies suggested that stable carbon isotope ratios of char or BC may not reliably reflect carbon isotopic signatures of the source vegetation. Overall, the apparently conflicting results throughout the literature regarding the observed fractionation suggest that combustion conditions may be responsible for the observed effects. The purpose of the present study was to gather more quantitative information on carbonaceous aerosols produced in controlled biomass burning, thereby having a potential impact on interpreting ambient atmospheric observations. Seven different biomass fuel types were burned under controlled conditions to determine the effect of the biomass type on the emitted particulate matter mass and stable carbon isotope composition of bulk and size segregated particles. Size segregated aerosol particles were collected using the total suspended particle (TSP) sampler and a micro-orifice uniform deposit impactor (MOUDI). The results demonstrated that particle emissions were dominated by the submicron particles in all biomass types. However, significant differences in emissions of submicron particles and their dominant sizes were found between different biomass fuels. The largest negative fractionation was obtained for the wood pellet fuel type while the largest positive isotopic fractionation was observed during the buckwheat shells combustion. The carbon isotope composition of MOUDI samples compared very well with isotope composition of TSP samples indicating consistency of the results. The measurements of the stable carbon isotope ratio in

Particle size distribution of UO sub 2 aerosols

Energy Technology Data Exchange (ETDEWEB)

Raghunath, B. (Radiation Safety Systems Div., BARC, Bombay (India)); Ramachandran, R.; Majumdar, S. (Radiometallurgy Div., BARC, Bombay (India))

1991-12-01

The Anderson cascade impactor has been used to determine the activity mean aerodynamic diameter and the particle size distribution of UO{sub 2} powders dispersed in the form of stable aerosols in an air medium. The UO{sub 2} powders obtained by the calcination of ammonium uranyl carbonate (AUC) and ammonium diuranate (ADU) precipitates have been used. (orig./MM).

Particle size dependence of biogenic secondary organic aerosol molecular composition

Science.gov (United States)

Tu, Peijun; Johnston, Murray V.

2017-06-01

Formation of secondary organic aerosol (SOA) is initiated by the oxidation of volatile organic compounds (VOCs) in the gas phase whose products subsequently partition to the particle phase. Non-volatile molecules have a negligible evaporation rate and grow particles at their condensation rate. Semi-volatile molecules have a significant evaporation rate and grow particles at a much slower rate than their condensation rate. Particle phase chemistry may enhance particle growth if it transforms partitioned semi-volatile molecules into non-volatile products. In principle, changes in molecular composition as a function of particle size allow non-volatile molecules that have condensed from the gas phase (a surface-limited process) to be distinguished from those produced by particle phase reaction (a volume-limited process). In this work, SOA was produced by β-pinene ozonolysis in a flow tube reactor. Aerosol exiting the reactor was size-selected with a differential mobility analyzer, and individual particle sizes between 35 and 110 nm in diameter were characterized by on- and offline mass spectrometry. Both the average oxygen-to-carbon (O / C) ratio and carbon oxidation state (OSc) were found to decrease with increasing particle size, while the relative signal intensity of oligomers increased with increasing particle size. These results are consistent with oligomer formation primarily in the particle phase (accretion reactions, which become more favored as the volume-to-surface-area ratio of the particle increases). Analysis of a series of polydisperse SOA samples showed similar dependencies: as the mass loading increased (and average volume-to-surface-area ratio increased), the average O / C ratio and OSc decreased, while the relative intensity of oligomer ions increased. The results illustrate the potential impact that particle phase chemistry can have on biogenic SOA formation and the particle size range where this chemistry becomes important.

Particle size dependence of biogenic secondary organic aerosol molecular composition

Directory of Open Access Journals (Sweden)

P. Tu

2017-06-01

Full Text Available Formation of secondary organic aerosol (SOA is initiated by the oxidation of volatile organic compounds (VOCs in the gas phase whose products subsequently partition to the particle phase. Non-volatile molecules have a negligible evaporation rate and grow particles at their condensation rate. Semi-volatile molecules have a significant evaporation rate and grow particles at a much slower rate than their condensation rate. Particle phase chemistry may enhance particle growth if it transforms partitioned semi-volatile molecules into non-volatile products. In principle, changes in molecular composition as a function of particle size allow non-volatile molecules that have condensed from the gas phase (a surface-limited process to be distinguished from those produced by particle phase reaction (a volume-limited process. In this work, SOA was produced by β-pinene ozonolysis in a flow tube reactor. Aerosol exiting the reactor was size-selected with a differential mobility analyzer, and individual particle sizes between 35 and 110 nm in diameter were characterized by on- and offline mass spectrometry. Both the average oxygen-to-carbon (O ∕ C ratio and carbon oxidation state (OSc were found to decrease with increasing particle size, while the relative signal intensity of oligomers increased with increasing particle size. These results are consistent with oligomer formation primarily in the particle phase (accretion reactions, which become more favored as the volume-to-surface-area ratio of the particle increases. Analysis of a series of polydisperse SOA samples showed similar dependencies: as the mass loading increased (and average volume-to-surface-area ratio increased, the average O ∕ C ratio and OSc decreased, while the relative intensity of oligomer ions increased. The results illustrate the potential impact that particle phase chemistry can have on biogenic SOA formation and the particle size range where this chemistry becomes

Optical Properties of the Urban Aerosol Particles Obtained from Ground Based Measurements and Satellite-Based Modelling Studies

Directory of Open Access Journals (Sweden)

Genrik Mordas

2015-01-01

Full Text Available Applications of satellite remote sensing data combined with ground measurements and model simulation were applied to study aerosol optical properties as well as aerosol long-range transport under the impact of large scale circulation in the urban environment in Lithuania (Vilnius. Measurements included the light scattering coefficients at 3 wavelengths (450, 550, and 700 nm measured with an integrating nephelometer and aerosol particle size distribution (0.5–12 μm and number concentration (Dpa > 0.5 μm registered by aerodynamic particle sizer. Particle number concentration and mean light scattering coefficient varied from relatively low values of 6.0 cm−3 and 12.8 Mm−1 associated with air masses passed over Atlantic Ocean to relatively high value of 119 cm−3 and 276 Mm−1 associated with South-Western air masses. Analysis shows such increase in the aerosol light scattering coefficient (276 Mm−1 during the 3rd of July 2012 was attributed to a major Sahara dust storm. Aerosol size distribution with pronounced coarse particles dominance was attributed to the presence of dust particles, while resuspended dust within the urban environment was not observed.

Evaluation of Aerosol Mixing State Classes in the GISS Modele-matrix Climate Model Using Single-particle Mass Spectrometry Measurements

Science.gov (United States)

Bauer, Susanne E.; Ault, Andrew; Prather, Kimberly A.

2013-01-01

Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 micron, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 micron contain large fractions of organic material, internally-mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

Study of Cl-containing urban aerosol particles by ion beam analytical methods

Energy Technology Data Exchange (ETDEWEB)

Angyal, A. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); University of Debrecen - ATOMKI, Department of Environmental Physics, H-4001 Debrecen, P.O. Box 51 (Hungary); Kertesz, Zs., E-mail: zsofi@atomki.h [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Szikszai, Z. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Szoboszlai, Z. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); University of Debrecen - ATOMKI, Department of Environmental Physics, H-4001 Debrecen, P.O. Box 51 (Hungary)

2010-06-15

Fine (aerodynamic diameter < 2.5 {mu}m) and coarse (10 {mu}m {>=} aerodynamic diameter {>=} 2.5 {mu}m) mode urban aerosol samples were collected with 2-h time resolution in the frame of several sampling campaigns between 2007 and 2009 in downtown Debrecen, East-Hungary. The elemental composition (for Z {>=} 13) of the samples was measured by particle induced X-ray emission (PIXE). On this basis sources of urban aerosol were determined by factor analysis. For both size fractions a source characterized by high chlorine content were found. However, the origin of the Cl-containing aerosol could not be ascertained. Further investigation of samples characterized with high Cl content were done on the ATOMKI Scanning Nuclear Microprobe Facility in order to determine the possible chemical composition of these particles and thus the potential sources. Morphology, size and elemental composition for Z {>=} 6 of around 1000 coarse mode particles were determined by using STIM (Scanning Transmission Ion Microscopy), light-element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the obtained dataset in order to group the particles; correlations between different elements were also calculated. Five possible sources of Cl were identified, from which four were anthropogenic: winter salting of streets, agriculture through fertilizers, buildings and industry; the natural group was sea-salt.

Spinning charged test particles and Cosmic Censorship

Energy Technology Data Exchange (ETDEWEB)

Caderni, N [Cambridge Univ. Inst. of Astronomy (UK); Calvani, M [Padua Univ. (Italy). Ist. di Astronomia

1979-04-16

The authors consider spinning charged test particles in the gravitational field of a rotating charged black hole, and it is shown that the hole cannot be destroyed, according to the Cosmic Censorship hypothesis.

Probing the micro-rheological properties of aerosol particles using optical tweezers

International Nuclear Information System (INIS)

Power, Rory M; Reid, Jonathan P

2014-01-01

The use of optical trapping techniques to manipulate probe particles for performing micro-rheological measurements on a surrounding fluid is well-established. Here, we review recent advances made in the use of optical trapping to probe the rheological properties of trapped particles themselves. In particular, we review observations of the continuous transition from liquid to solid-like viscosity of sub-picolitre supersaturated solution aerosol droplets using optical trapping techniques. Direct measurements of the viscosity of the particle bulk are derived from the damped oscillations in shape following coalescence of two particles, a consequence of the interplay between viscous and surface forces and the capillary driven relaxation of the approximately spheroidal composite particle. Holographic optical tweezers provide a facile method for the manipulation of arrays of particles allowing coalescence to be controllably induced between two micron-sized aerosol particles. The optical forces, while sufficiently strong to confine the composite particle, are several orders of magnitude weaker than the capillary forces driving relaxation. Light, elastically back-scattered by the particle, is recorded with sub-100 ns resolution allowing measurements of fast relaxation (low viscosity) dynamics, while the brightfield image can be used to monitor the shape relaxation extending to times in excess of 1000 s. For the slowest relaxation dynamics studied (particles with the highest viscosity) the presence and line shape of whispering gallery modes in the cavity enhanced Raman spectrum can be used to infer the relaxation time while serving the dual purpose of allowing the droplet size and refractive index to be measured with accuracies of ±0.025% and ±0.1%, respectively. The time constant for the damped relaxation can be used to infer the bulk viscosity, spanning from the dilute solution limit to a value approaching that of a glass, typically considered to be >10 12 �

Probing the micro-rheological properties of aerosol particles using optical tweezers

Science.gov (United States)

Power, Rory M.; Reid, Jonathan P.

2014-07-01

The use of optical trapping techniques to manipulate probe particles for performing micro-rheological measurements on a surrounding fluid is well-established. Here, we review recent advances made in the use of optical trapping to probe the rheological properties of trapped particles themselves. In particular, we review observations of the continuous transition from liquid to solid-like viscosity of sub-picolitre supersaturated solution aerosol droplets using optical trapping techniques. Direct measurements of the viscosity of the particle bulk are derived from the damped oscillations in shape following coalescence of two particles, a consequence of the interplay between viscous and surface forces and the capillary driven relaxation of the approximately spheroidal composite particle. Holographic optical tweezers provide a facile method for the manipulation of arrays of particles allowing coalescence to be controllably induced between two micron-sized aerosol particles. The optical forces, while sufficiently strong to confine the composite particle, are several orders of magnitude weaker than the capillary forces driving relaxation. Light, elastically back-scattered by the particle, is recorded with sub-100 ns resolution allowing measurements of fast relaxation (low viscosity) dynamics, while the brightfield image can be used to monitor the shape relaxation extending to times in excess of 1000 s. For the slowest relaxation dynamics studied (particles with the highest viscosity) the presence and line shape of whispering gallery modes in the cavity enhanced Raman spectrum can be used to infer the relaxation time while serving the dual purpose of allowing the droplet size and refractive index to be measured with accuracies of ±0.025% and ±0.1%, respectively. The time constant for the damped relaxation can be used to infer the bulk viscosity, spanning from the dilute solution limit to a value approaching that of a glass, typically considered to be >1012 Pa s, whilst

Spinning charged test particles and Cosmic Censorship

International Nuclear Information System (INIS)

Caderni, N.; Calvani, M.

1979-01-01

The authors consider spinning charged test particles in the gravitational field of a rotating charged black hole, and it is shown that the hole cannot be destroyed, according to the Cosmic Censorship hypothesis. (Auth.)

Seasonal variations in aerosol particle composition at the puy-de-Dôme research station in France

Directory of Open Access Journals (Sweden)

E. J. Freney

2011-12-01

Full Text Available Detailed investigations of the chemical and microphysical properties of atmospheric aerosol particles were performed at the puy-de-Dôme (pdD research station (1465 m in autumn (September and October 2008, winter (February and March 2009, and summer (June 2010 using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS. Over the three campaigns, the average mass concentrations of the non-refractory submicron particles ranged from 10 μg m⁻³ up to 27 μg m⁻³. Highest nitrate and ammonium mass concentrations were measured during the winter and during periods when marine modified airmasses were arriving at the site, whereas highest concentrations of organic particles were measured during the summer and during periods when continental airmasses arrived at the site. The measurements reported in this paper show that atmospheric particle composition is strongly influenced by both the season and the origin of the airmass. The total organic mass spectra were analysed using positive matrix factorisation to separate individual organic components contributing to the overall organic particle mass concentrations. These organic components include a low volatility oxygenated organic aerosol particle (LV-OOA and a semi-volatile organic aerosol particle (SV-OOA. Correlations of the LV-OOA components with fragments of m/z 60 and m/z 73 (mass spectral markers of wood burning during the winter campaign suggest that wintertime LV-OOA are related to aged biomass burning emissions, whereas organic aerosol particles measured during the summer are likely linked to biogenic sources. Equivalent potential temperature calculations, gas-phase, and LIDAR measurements define whether the research site is in the planetary boundary layer (PBL or in the free troposphere (FT/residual layer (RL. We observe that SV-OOA and nitrate particles are associated with air masses arriving from the PBL where as particle composition measured from RL

Experimental studies of the gravitational agglomeration of aerosols. Pt. 1

International Nuclear Information System (INIS)

Ball, M.H.E.; Mitchell, J.P.; Kissane, M.P.

1990-06-01

Experiments have been performed to determine the extent of gravitational agglomeration between micron-sized airborne particles suspended initially as two discrete log-normal number-size distributions. These aerosols were generated from commercially-available glass microspheres using a standard dry powder dispersing technique. They were injected directly into a sedimentation vessel and their settling behaviour was studied using a TSI Aerodynamic Particle Sizer (APS33B) to obtain particle number-size data, and a deposition sampler to obtain the corresponding mass-based data. Additionally, samples were collected on membrane filters to measure total aerosol mass concentrations, and a Faraday-cup aerosol electrometer was used to determine the net average electrostatic charge of the particles. While mass-based techniques were not sufficiently sensitive to detect gravitational agglomeration, the process could be monitored with reasonable success by number-based methods. APS33B measurements were made in the presence and absence of larger particles. No significant increase in the rate of removal of the small particles was observed. These studies therefore indicated that gravitational agglomeration is small or negligible under the specified test conditions. (author)

Influence of aerosol particles, clouds, and condensation trails on the climate in Bavaria

International Nuclear Information System (INIS)

Wiegner, M.

1994-01-01

Human interventions in the climate system occur mainly through the emission of trace gases and aerosol particles. Emissions of aerosol particles can also change the properties of clouds. Climate model calculations have shown that an increase in trace gas concentrations causes the lower atmosphere to warm. According to numerical studies performed during the past few years, anthropogenic aerosol sources can have a cooling effect which is of the same order as the warming caused by greenhouse gases. However, due to their differing time constants and spatial characteristics the two effects are unlikely to neutralise each other over extended regions for any length of time. The currently available models with their very coarse spatial resolution are not suitable for making climatological predictions for Bavaria on the basis of cloud or aerosol properties. What can be done at present is to formulate warnings and propose measures for reducing environmental hazards and conserving our natural surroundings as far as possible. (orig.) [de

Mixing state of particles with secondary species by single particle aerosol mass spectrometer in an atmospheric pollution event

Science.gov (United States)

Xu, Lingling; Chen, Jinsheng

2016-04-01

Single particle aerosol mass spectrometer (SPAMS) was used to characterize size distribution, chemical composition, and mixing state of particles in an atmospheric pollution event during 20 Oct. - 5 Nov., 2015 in Xiamen, Southeast China. A total of 533,012 particle mass spectra were obtained and clustered into six groups, comprising of industry metal (4.5%), dust particles (2.6%), carbonaceous species (70.7%), K-Rich particles (20.7%), seasalt (0.6%) and other particles (0.9%). Carbonaceous species were further divided into EC (70.6%), OC (28.5%), and mixed ECOC (0.9%). There were 61.7%, 58.3%, 4.0%, and 14.6% of particles internally mixed with sulfate, nitrate, ammonium and C2H3O, respectively, indicating that these particles had undergone significant aging processing. Sulfate was preferentially mixed with carbonaceous particles, while nitrate tended to mix with metal-containing and dust particles. Compared to clear days, the fractions of EC-, metal- and dust particles remarkably increased, while the fraction of OC-containing particles decreased in pollution days. The mixing state of particles, excepted for OC-containing particles with secondary species was much stronger in pollution days than that in clear days, which revealed the significant influence of secondary particles in atmospheric pollution. The different activity of OC-containing particles might be related to their much smaller aerodynamic diameter. These results could improve our understanding of aerosol characteristics and could be helpful to further investigate the atmospheric process of particles.

Hygroscopic growth of sub-micrometer and one-micrometer aerosol particles measured during ACE-Asia

Directory of Open Access Journals (Sweden)

A. Massling

2007-06-01

Full Text Available Hygroscopic properties of aerosol particles in the sub-micrometer and one-micrometer size ranges were measured during the ACE-Asia study (Aerosol Characterization Experiment-Asia in spring 2001. The measurements took place off the coasts of Japan, Korea, and China. All instruments contributing to this study were deployed in a container on the forward deck of the NOAA Research Vessel Ronald H. Brown. Air masses with primarily marine influence and air masses from the Asian continent affected by both anthropogenic sources and by the transport of desert dust aerosol were encountered during the cruise.

Results showed very different hygroscopic behavior in the sub-micrometer size range compared to the one-micrometer size range. In general, for all continentally influenced air masses, the one-micrometer particle population was characterized by two different particle groups – a nearly hydrophobic fraction with growth factors around 1.0 representative of dust particles and a sea salt fraction with hygroscopic growth factors around 2.0. The number fraction of dust particles was generally about 60% independent of long-range air mass origin.

For sub-micrometer particles, a dominant, more hygroscopic particle fraction with growth factors between 1.5 and 1.9 (depending on dry particle size consistent with ammonium sulfate or non-neutralized sulfates as major component was always found. In marine air masses and for larger sizes within the sub-micrometer range (Dp=250 and 350 nm, a sea salt fraction with growth factors between 2.0 and 2.1 was also observed. For all other air masses, the more hygroscopic particle fraction in the sub-micrometer size range was mostly accompanied by a less hygroscopic particle fraction with growth factors between 1.20 and 1.55 depending on both the continental sources and the dry particle size. Number fractions of this particle group varied between 4 and 39% depending on dry particle size and air mass

Charged particle acceleration with plasmas

International Nuclear Information System (INIS)

Bravo O, A.

1989-01-01

Under certain conditions it is possible to create spatial charge waves (OCE) in a plasma (ionized gas) through some disturbance mechanism, the phenomenon produces electric fields of high intensity that are propagated at velocities near to a c. When charged particles are connected to such OCE they may be accelerated to very high energies in short distances. At present electric fields of approximately 10 7 V/cm have been observed. (Author). 4 refs

Experimental study of the effect of wearing dust-proof mask on inhaled aerosol particle size

International Nuclear Information System (INIS)

Lu Shunguang; Mei Chongsheng; Wu Yuangqing; Ren Liuan.

1985-01-01

This paper describes a method for measuring particle size of inhaled aerosol with a phantom of human head wearing dust-proof mask and a cascade impactor. The results showed that AMAD of inhaled aerosol was degraded and the size distribution of particles changed when the dust-proof mask was wearing. The leak rate of mask increased as the size of dust particles decreased. The results are applicable to estimate internal exposure dose and to evaluate the dust-proof capacity of mask

Observations and Modeling of the Green Ocean Amazon 2014/15: Transmission Electron Microscopy Analysis of Aerosol Particles Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Buseck, Peter [Arizona State Univ., Tempe, AZ (United States)

2016-03-01

During two Intensive Operational Periods (IOP), we collected samples at 3-hour intervals for transmission electron microscopy analysis. The resulting transmission electron microscopy images and compositions were analyzed for the samples of interest. Further analysis will be done especially for the plume of interest. We found solid spherical organic particles from rebounded samples collected with Professor Scot Martin’s group (Harvard University). Approximately 30% of the rebounded particles at 95% relative humidity were spherical organic particles. Their sources and formation process are not known, but such spherical particles could be solid and will have heterogeneous chemical reactions. We observed many organic particles that are internally mixed with inorganic elements such as potassium and nitrogen. They are either homogeneously mixed or have inorganic cores with organic aerosol coatings. Samples collected from the Manaus, Brazil, pollution plume included many nano-size soot particles mixed with organic material and sulfate. Aerosol particles from clean periods included organic aerosol particles, sulfate, sea salt, dust, and primary biogenic aerosol particles. There was more dust, primary biogenic aerosol, and tar balls in samples taken during IOP1 than those taken during IOP2. Many dust particles were found between March 2 and 3.

Expanding Single Particle Mass Spectrometer Analyses for the Identification of Microbe Signatures in Sea Spray Aerosol.

Science.gov (United States)

Sultana, Camille M; Al-Mashat, Hashim; Prather, Kimberly A

2017-10-03

Ocean-derived microbes in sea spray aersosol (SSA) have the potential to influence climate and weather by acting as ice nucleating particles in clouds. Single particle mass spectrometers (SPMSs), which generate in situ single particle composition data, are excellent tools for characterizing aerosols under changing environmental conditions as they can provide high temporal resolution and require no sample preparation. While SPMSs have proven capable of detecting microbes, these instruments have never been utilized to definitively identify aerosolized microbes in ambient sea spray aersosol. In this study, an aerosol time-of-flight mass spectrometer was used to analyze laboratory generated SSA produced from natural seawater in a marine aerosol reference tank. We present the first description of a population of biological SSA mass spectra (BioSS), which closely match the ion signatures observed in previous terrestrial microbe studies. The fraction of BioSS dramatically increased in the largest supermicron particles, consistent with field and laboratory measurements of microbes ejected by bubble bursting, further supporting the assignment of BioSS mass spectra as microbes. Finally, as supported by analysis of inorganic ion signals, we propose that dry BioSS particles have heterogeneous structures, with microbes adhered to sodium chloride nodules surrounded by magnesium-enriched coatings. Consistent with this structure, chlorine-containing ion markers were ubiquitous in BioSS spectra and identified as possible tracers for distinguishing recently aerosolized marine from terrestrial microbes.

Coulomb-Fourier representation approach to three-body scattering with charged particles

International Nuclear Information System (INIS)

Alt, E.O.; Levin, S.B.; Yakovlev, S.L.

2004-01-01

We present a novel approach for calculating charged-composite particle scattering. It consists in eliminating by means of a suitably chosen representation that part of the interaction which is of longest range and, hence, gives rise to all the troublesome features which plague charged particle scattering theories. In this paper only the simplest case is considered, namely that of two charged and one neutral particles which interact via pairwise strong potentials, and a repulsive Coulomb potential between the charged particles

Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere

Directory of Open Access Journals (Sweden)

K. Hara

2011-06-01

Full Text Available Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005–2006. The CN concentration reached a maximum in the summer, although the number concentrations of fine particles (D_p>0.3 μm and coarse particles (D_p>2.0 μm increased during the winter–spring. The CN concentration was 30–2200 cm⁻³ near the surface (surface – 500 m and 7–7250 cm⁻³ in the lower free troposphere (>1500 m. During the austral summer, higher CN concentration was often observed in the lower free troposphere, where the number concentrations in fine and coarse modes were remarkably lower. The frequent appearance of higher CN concentrations in the free troposphere relative to continuous aerosol measurements at the ground strongly suggests that new particle formation is more likely to occur in the lower free troposphere in Antarctic regions. Seasonal variations of size distribution of fine-coarse particles show that the contribution of the coarse mode was greater in the winter–spring than in summer because of the dominance of sea-salt particles in the winter–spring. The number concentrations of fine and coarse particles were high in air masses from the ocean and mid-latitudes. Particularly, aerosol enhancement was observed not only in the boundary layer, but also in the lower free troposphere during and immediately after Antarctic haze events occurring in May, July and September.

Dispersion of aerosol particles in the free atmosphere using ensemble forecasts

Directory of Open Access Journals (Sweden)

T. Haszpra

2013-10-01

Full Text Available The dispersion of aerosol particle pollutants is studied using 50 members of an ensemble forecast in the example of a hypothetical free atmospheric emission above Fukushima over a period of 2.5 days. Considerable differences are found among the dispersion predictions of the different ensemble members, as well as between the ensemble mean and the deterministic result at the end of the observation period. The variance is found to decrease with the particle size. The geographical area where a threshold concentration is exceeded in at least one ensemble member expands to a 5–10 times larger region than the area from the deterministic forecast, both for air column "concentration" and in the "deposition" field. We demonstrate that the root-mean-square distance of any particle from its own clones in the ensemble members can reach values on the order of one thousand kilometers. Even the centers of mass of the particle cloud of the ensemble members deviate considerably from that obtained by the deterministic forecast. All these indicate that an investigation of the dispersion of aerosol particles in the spirit of ensemble forecast contains useful hints for the improvement of risk assessment.

21 CFR 892.5050 - Medical charged-particle radiation therapy system.

Science.gov (United States)

2010-04-01

...-particle radiation therapy system. (a) Identification. A medical charged-particle radiation therapy system... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical charged-particle radiation therapy system... equipment, patient and equipment supports, treatment planning computer programs, component parts, and...

DSMC multicomponent aerosol dynamics: Sampling algorithms and aerosol processes

Science.gov (United States)

Palaniswaamy, Geethpriya

The post-accident nuclear reactor primary and containment environments can be characterized by high temperatures and pressures, and fission products and nuclear aerosols. These aerosols evolve via natural transport processes as well as under the influence of engineered safety features. These aerosols can be hazardous and may pose risk to the public if released into the environment. Computations of their evolution, movement and distribution involve the study of various processes such as coagulation, deposition, condensation, etc., and are influenced by factors such as particle shape, charge, radioactivity and spatial inhomogeneity. These many factors make the numerical study of nuclear aerosol evolution computationally very complicated. The focus of this research is on the use of the Direct Simulation Monte Carlo (DSMC) technique to elucidate the role of various phenomena that influence the nuclear aerosol evolution. In this research, several aerosol processes such as coagulation, deposition, condensation, and source reinforcement are explored for a multi-component, aerosol dynamics problem in a spatially homogeneous medium. Among the various sampling algorithms explored the Metropolis sampling algorithm was found to be effective and fast. Several test problems and test cases are simulated using the DSMC technique. The DSMC results obtained are verified against the analytical and sectional results for appropriate test problems. Results show that the assumption of a single mean density is not appropriate due to the complicated effect of component densities on the aerosol processes. The methods developed and the insights gained will also be helpful in future research on the challenges associated with the description of fission product and aerosol releases.

A scintillation detector set measuring the charge particle energy

International Nuclear Information System (INIS)

Dore, Chantal.

1979-01-01

The S143 experiment, at CERN in 1976, needed both the measurement and the identification of light nuclei, and especially the separation between 3 H and 3 He, over a large energy range. In the chosen solution, in addition to semiconductor detectors, some scintillation counters are used. The non-linearity of light versus energy of charged particles was complicated by the fact there was two different linear laws according to the charge of particles. To obtain good analogic signals over a dynamic range nearly equal to 200, the signals from several dynodes were used simultaneously. In the experimental setting up, each scintillator was put directly in contact with the corresponding photocathode. In spite of a special shielding, some perturbations due to the magnet placed close by required to bring important corrections to linear laws. Thanks to complementary informations from semiconductor counters, a full separation between charge 1 and charge 2 particles was possible. A suitable identification as guaranted among charge 1 particles, but only kinematic constraints gave the possibility to extract 4 He corresponding to the elastic scattering [fr

Investigating biomass burning aerosol morphology using a laser imaging nephelometer

Science.gov (United States)

Manfred, Katherine M.; Washenfelder, Rebecca A.; Wagner, Nicholas L.; Adler, Gabriela; Erdesz, Frank; Womack, Caroline C.; Lamb, Kara D.; Schwarz, Joshua P.; Franchin, Alessandro; Selimovic, Vanessa; Yokelson, Robert J.; Murphy, Daniel M.

2018-02-01

Particle morphology is an important parameter affecting aerosol optical properties that are relevant to climate and air quality, yet it is poorly constrained due to sparse in situ measurements. Biomass burning is a large source of aerosol that generates particles with different morphologies. Quantifying the optical contributions of non-spherical aerosol populations is critical for accurate radiative transfer models, and for correctly interpreting remote sensing data. We deployed a laser imaging nephelometer at the Missoula Fire Sciences Laboratory to sample biomass burning aerosol from controlled fires during the FIREX intensive laboratory study. The laser imaging nephelometer measures the unpolarized scattering phase function of an aerosol ensemble using diode lasers at 375 and 405 nm. Scattered light from the bulk aerosol in the instrument is imaged onto a charge-coupled device (CCD) using a wide-angle field-of-view lens, which allows for measurements at 4-175° scattering angle with ˜ 0.5° angular resolution. Along with a suite of other instruments, the laser imaging nephelometer sampled fresh smoke emissions both directly and after removal of volatile components with a thermodenuder at 250 °C. The total integrated aerosol scattering signal agreed with both a cavity ring-down photoacoustic spectrometer system and a traditional integrating nephelometer within instrumental uncertainties. We compare the measured scattering phase functions at 405 nm to theoretical models for spherical (Mie) and fractal (Rayleigh-Debye-Gans) particle morphologies based on the size distribution reported by an optical particle counter. Results from representative fires demonstrate that particle morphology can vary dramatically for different fuel types. In some cases, the measured phase function cannot be described using Mie theory. This study demonstrates the capabilities of the laser imaging nephelometer instrument to provide realtime, in situ information about dominant particle

Aerosol nucleation induced by a high energy particle beam

DEFF Research Database (Denmark)

Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

The effect of ions in aerosol nucleation is a subject where much remains to be discovered. That ions can enhance nucleation has been shown by theory, observations, and experiments. However, the exact mechanism still remains to be determined. One question is if the nature of the ionization affects...... the nucleation. This is an essential question since many experiments have been performed using radioactive sources that ionize differently than the cosmic rays which are responsible for the majority of atmospheric ionization. Here we report on an experimental study of sulphuric acid aerosol nucleation under near...... atmospheric conditions using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear and significant contribution from ion induced nucleation and consider this to be an unambiguous observation of the ion-effect on aerosol nucleation using a particle beam under conditions not far...

Trace element similarity groups in north Florida Spanish moss: evidence for direct uptake of aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Sheline, J.; Akselsson, R.; Winchester, J.W.

1976-02-20

The elemental composition of 10 samples of Spanish moss Tillandsia usneoides L. collected mainly in forested areas near Tallahassee, Florida, has been compared to the composition of the ambient aerosol particle background in the forest measured as a function of particle size. For forest samples, moss composition is similar to the composition of aerosol particles greater than about 0.5-..mu..m diameter for the elements S, Cl, Ti, V, Fe, Ni, Zn, Br, Pb, and possibly Cu. Elements relatively enriched in the moss fall into two groups, K, Rb, Zr and Ca, Sr, Mn, based on detailed association patterns. No evidence is found for an enrichment, relative to the ambient aerosol, of pollution-derived elements Pb, Br, V, and Ni, although those elements are found at higher concentrations in moss samples from locations nearer roadways or oil-fired power plants. The moss appears to have potential value as an indicator of time average aerosol composition for particles of greater than or equal to 0.5 ..mu..m, except for the enriched elements, which may have longer biological retention times. (auth)

Method of measuring a profile of the density of charged particles in a particle beam

International Nuclear Information System (INIS)

Hyman, L.G.; Jankowski, D.J.

1975-01-01

A profile of the relative density of charged particles in a beam is obtained by disposing a number of rods parallel to each other in a plane perpendicular to the beam and shadowing the beam. A second number of rods is disposed perpendicular to the first rods in a plane perpendicular to the beam and also shadowing the beam. Irradiation of the rods by the beam of charged particles creates radioactive isotopes in a quantity proportional to the number of charged particles incident upon the rods. Measurement of the radioactivity of each of the rods provides a measure of the quantity of radioactive material generated thereby and, together with the location of the rods, provides information sufficient to identify a profile of the density of charged particles in the beam

Ultracold Fermi and Bose gases and Spinless Bose Charged Sound Particles

Directory of Open Access Journals (Sweden)

Minasyan V.

2011-10-01

Full Text Available We propose a novel approach for investigation of the motion of Bose or Fermi liquid (or gas which consists of decoupled electrons and ions in the uppermost hyperfine state. Hence, we use such a concept as the fluctuation motion of “charged fluid particles” or “charged fluid points” representing a charged longitudinal elastic wave. In turn, this elastic wave is quantized by spinless longitudinal Bose charged sound particles with the rest mass m and charge e 0 . The existence of spinless Bose charged sound particles allows us to present a new model for description of Bose or Fermi liquid via a non-ideal Bose gas of charged sound particles . In this respect, we introduce a new postulation for the superfluid component of Bose or Fermi liquid determined by means of charged sound particles in the condensate, which may explain the results of experiments connected with ultra-cold Fermi gases of spin-polarized hydrogen, 6 Li and 40 K, and such a Bose gas as 87 Rb in the uppermost hyperfine state, where the Bose- Einstein condensation of charged sound particles is realized by tuning the magnetic field.

Comprehensive Airborne in Situ Characterization of Atmospheric Aerosols: From Angular Light Scattering to Particle Microphysics

Science.gov (United States)

Espinosa, W. Reed

A comprehensive understanding of atmospheric aerosols is necessary both to understand Earth's climate as well as produce skillful air quality forecasts. In order to advance our understanding of aerosols, the Laboratory for Aerosols, Clouds and Optics (LACO) has recently developed the Imaging Polar Nephelometer instrument concept for the in situ measurement of aerosol scattering properties. Imaging Nephelometers provide measurements of absolute phase function and polarized phase function over a wide angular range, typically 3 degrees to 177 degrees, with an angular resolution smaller than one degree. The first of these instruments, the Polarized Imaging Nephelometer (PI-Neph), has taken part in five airborne field experiments and is the only modern aerosol polar nephelometer to have flown aboard an aircraft. A method for the retrieval of aerosol optical and microphysical properties from I-Neph measurements is presented and the results are compared with existing measurement techniques. The resulting retrieved particle size distributions agree to within experimental error with measurements made by commercial optical particle counters. Additionally, the retrieved real part of the refractive index is generally found to be within the predicted error of 0.02 from the expected values for three species of humidified salt particles, whose refractive index is well established. A synopsis is then presented of aerosol scattering measurements made by the PI-Neph during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) and the Deep Convection Clouds and Chemistry (DC3) field campaigns. To better summarize these extensive datasets a novel aerosol classification scheme is developed, making use of ancillary data that includes gas tracers, chemical composition, aerodynamic particle size and geographic location, all independent of PI-Neph measurements. Principal component analysis (PCA) is then used to reduce the

Aerosol particle size does not predict pharmacokinetic determined lung dose in children

DEFF Research Database (Denmark)

Bønnelykke, Klaus; Chawes, Bo L K; Vindfeld, Signe

2013-01-01

In vitro measures of aerosol particles size, such as the fine particle mass, play a pivotal role for approval of inhaled anti-asthmatic drugs. However, the validity as a measure of dose to the lungs in children lacks evidence. In this study we investigated for the first time the association between...... an in vivo estimate of lung dose of inhaled drug in children and the corresponding particle size segments assessed ex vivo. Lung dose of fluticasone propionate after inhalation from a dry powder inhaler (Diskus®) was studied in 23 children aged 4-7 and 12-15 years with mild asthma. Six-hour pharmacokinetics...... was assessed after single inhalation. The corresponding emitted mass of drug in segments of aerosol particle size was assessed ex vivo by replicating the inhalation flows recorded by transducers built into the Diskus® inhaler and re-playing them in a breathing simulator. There was no correlation between any...

In vitro and in vivo lung deposition of coated magnetic aerosol particles.

Science.gov (United States)

Xie, Yuanyuan; Longest, P Worth; Xu, Yun Hao; Wang, Jian Ping; Wiedmann, Timothy Scott

2010-11-01

The magnetic induced deposition of polydispersed aerosols composed of agglomerated superparamagnetic particles was measured with an in vitro model system and in the mouse trachea and deep lung for the purpose of investigating the potential of site specific respiratory drug delivery. Oleic acid coated superparamagnetic particles were prepared and characterized by TEM, induced magnetic moment, and iron content. The particles were dispersed in cyclohexane, aerosolized with an ultrasonic atomizer and dried by sequential reflux and charcoal columns. The fraction of iron deposited on glass tubes increased with particle size and decreasing flow rate. High deposition occurred with a small diameter tube, but the deposition fraction was largely independent of tube size at larger diameters. Results from computational fluid dynamics qualitatively agreed with the experimental results. Enhanced deposition was observed in the mouse lung but not in the trachea consistent with the analysis of the aerodynamic time allowed for deposition and required magnetic deposition time. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Bibliography of integral charged particle nuclear data. Archival edition

International Nuclear Information System (INIS)

Burrows, T.W.; Dempsey, P.

1980-03-01

This is the fourth annual edition of the National Nuclear Data Center charged-particle bibliography. This edition is cumulative and supersedes the previous editions. The bibliography's primary aims are to satisfy the need for a concise and comprehensive index of integral charged-particle cross section data and to provide an index of charged-particle data compiled in the international exchange format, EXFOR. This part of the publication deals with isotope production; references are ordered by mass of the nuclide produced. The present publication is an archival volume; future publications will be cumulative supplements to this edition

Single charging events on colloidal particles in a nonpolar liquid with surfactant

Science.gov (United States)

Schreuer, Caspar; Vandewiele, Stijn; Brans, Toon; Strubbe, Filip; Neyts, Kristiaan; Beunis, Filip

2018-01-01

Electrical charging of colloidal particles in nonpolar liquids due to surfactant additives is investigated intensively, motivated by its importance in a variety of applications. Most methods rely on average electrophoretic mobility measurements of many particles, which provide only indirect information on the charging mechanism. In the present work, we present a method that allows us to obtain direct information on the charging mechanism, by measuring the charge fluctuations on individual particles with a precision higher than the elementary charge using optical trapping electrophoresis. We demonstrate the capabilities of the method by studying the influence of added surfactant OLOA 11000 on the charging of single colloidal PMMA particles in dodecane. The particle charge and the frequency of charging events are investigated both below and above the critical micelle concentration (CMC) and with or without applying a DC offset voltage. It is found that at least two separate charging mechanisms are present below the critical micelle concentration. One mechanism is a process where the particle is stripped from negatively charged ionic molecules. An increase in the charging frequency with increased surfactant concentration suggests a second mechanism that involves single surfactant molecules. Above the CMC, neutral inverse micelles can also be involved in the charging process.

Searches for Fractionally Charged Particles: What Should Be Done Next?

Energy Technology Data Exchange (ETDEWEB)

Perl, Martin L.; /SLAC

2009-01-15

Since the initial measurements of the electron charge a century ago, experimenters have faced the persistent question as to whether elementary particles exist that have charges that are fractional multiples of the electron charge. I concisely review the results of the last 50 years of searching for fractional charge particles with no confirmed positive results. I discuss the question of whether more searching is worthwhile?

Distinct high molecular weight organic compound (HMW-OC) types in aerosol particles collected at a coastal urban site

Science.gov (United States)

Dall'Osto, M.; Healy, R. M.; Wenger, J. C.; O'Dowd, C.; Ovadnevaite, J.; Ceburnis, D.; Harrison, Roy M.; Beddows, D. C. S.

2017-12-01

Organic oligomers were discovered in laboratory-generated atmospheric aerosol over a decade ago. However, evidence for the presence of oligomers in ambient aerosols is scarce and mechanisms for their formation have yet to be fully elucidated. In this work, three unique aerosol particle types internally mixed with High molecular weight organic compounds (HMW-OC) species - likely oligomers - were detected in ambient air using single particle Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS) in Cork (Ireland) during winter 2009. These particle types can be described as follows: (1) HMW-OCs rich in organic nitrogen - possibly containing nitrocatechols and nitroguaiacols - originating from primary emissions of biomass burning particles during evening times; (2) HMW-OCs internally mixed with nitric acid, occurring in stagnant conditions during night time; and (3) HMW-OCs internally mixed with sea salt, likely formed via photochemical reactions during day time. The study exemplifies the power of methodologies capable of monitoring the simultaneous formation of organic and inorganic particle-phase reaction products. Primary emissions and atmospheric aging of different types of HMW-OC contributes to aerosol with a range of acidity, hygroscopic and optical properties, which can have different impacts on climate and health.

Evaluating the impact of aerosol particles above cloud on cloud optical depth retrievals from MODIS

Science.gov (United States)

Alfaro-Contreras, Ricardo; Zhang, Jianglong; Campbell, James R.; Holz, Robert E.; Reid, Jeffrey S.

2014-05-01

Using two different operational Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical depth (COD) retrievals (0.86 versus 1.6 µm), we evaluate the impact of above-cloud smoke aerosol particles on near-IR (0.86 µm) COD retrievals. Aerosol Index (AI) from the collocated Ozone Monitoring Instrument (OMI) are used to identify above-cloud aerosol particle loading over the southern Atlantic Ocean, including both smoke and dust from the African subcontinent. Collocated Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation data constrain cloud phase and provide contextual above-cloud aerosol optical depth. The frequency of occurrence of above-cloud aerosol events is depicted on a global scale for the spring and summer seasons from OMI and Cloud Aerosol Lidar with Orthogonal Polarization. Seasonal frequencies for smoke-over-cloud off the southwestern Africa coastline reach 20-50% in boreal summer. We find a corresponding low COD bias of 10-20% for standard MODIS COD retrievals when averaged OMI AI are larger than 1. No such bias is found over the Saharan dust outflow region off northern Africa, since both MODIS 0.86 and 1.6 µm channels are vulnerable to radiance attenuation due to dust particles. A similar result is found for a smaller domain, in the Gulf of Tonkin region, from smoke advection over marine stratocumulus clouds and outflow into the northern South China Sea in spring. This study shows the necessity of accounting for the above-cloud aerosol events for future studies using standard MODIS cloud products in biomass burning outflow regions, through the use of collocated OMI AI and supplementary MODIS 1.6 µm COD products.

Radon decay products and 10–1100 nm aerosol particles in Postojna Cave

Directory of Open Access Journals (Sweden)

M. Bezek

2013-03-01

Full Text Available At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn decay products and the number concentration and size distribution of aerosol particles in the size range of 10–1100 nm were monitored, with the focus on the unattached fraction (fun of radon decay products (RnDPs, a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm−3 than in winter (2800 cm−3, and was dominated by 50 nm particles (related to the attached RnDPs in winter. This explains the higher fun values in summer (0.75 and the lower winter measurement (0.04 and, consequently, DCFD values of 43.6 and 13.1 mSv WLM−1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

Observations of the vertical concentrations of aerosol particles in the boundary layer by means of tethered balloon method

Energy Technology Data Exchange (ETDEWEB)

Ishioka, Futoshi; Lee, D.I; Taniguchi, Takashi; Kikuchi,Katsuhiro

1988-09-30

In general, it is difficult to accurately understand the behavior of aerosol particles in the boundary layer above urban areas because aerosol sources are influenced by time-dependent factors and local climate. To overcome this difficulty, a particle counter which can count Mie particles with diameters of 0.3 /mu/m or more in five diameter ranges was installed on a large tehered balloon. With this method, the vertical distribution of aerosol concentration was measured in several areas different in meteorological condition, and the dependence of the particle behavior on particle diameter was studied. As a result, it has been revealed that the results of the observations explained above agree with the results of studies conducted in the past, but that dependence on particle diameter is not significant. 37 references, 21 figures, 1 table.

Fog camera to visualize ionizing charged particles

International Nuclear Information System (INIS)

Trujillo A, L.; Rodriguez R, N. I.; Vega C, H. R.

2014-10-01

The human being can not perceive the different types of ionizing radiation, natural or artificial, present in the nature, for what appropriate detection systems have been developed according to the sensibility to certain radiation type and certain energy type. The objective of this work was to build a fog camera to visualize the traces, and to identify the trajectories, produced by charged particles with high energy, coming mainly of the cosmic rays. The origin of the cosmic rays comes from the solar radiation generated by solar eruptions where the protons compose most of this radiation. It also comes, of the galactic radiation which is composed mainly of charged particles and gamma rays that comes from outside of the solar system. These radiation types have energy time millions higher that those detected in the earth surface, being more important as the height on the sea level increases. These particles in their interaction produce secondary particles that are detectable by means of this cameras type. The camera operates by means of a saturated atmosphere of alcohol vapor. In the moment in that a charged particle crosses the cold area of the atmosphere, the medium is ionized and the particle acts like a condensation nucleus of the alcohol vapor, leaving a visible trace of its trajectory. The built camera was very stable, allowing the detection in continuous form and the observation of diverse events. (Author)

Morphology, Composition, and Mixing State of Individual Aerosol Particles in Northeast China during Wintertime

Directory of Open Access Journals (Sweden)

Liang Xu

2017-02-01

Full Text Available Northeast China is located in a high latitude area of the world and undergoes a cold season that lasts six months each year. Recently, regional haze episodes with high concentrations of fine particles (PM2.5 have frequently been occurring in Northeast China during the heating period, but little information has been available. Aerosol particles were collected in winter at a site in a suburban county town (T1 and a site in a background rural area (T2. Morphology, size, elemental composition, and mixing state of individual aerosol particles were characterized by transmission electron microscopy (TEM. Aerosol particles were mainly composed of organic matter (OM and S-rich and certain amounts of soot and K-rich. OM represented the most abundant particles, accounting for 60.7% and 53.5% at the T1 and T2 sites, respectively. Abundant spherical OM particles were likely emitted directly from coal-burning stoves. Soot decreased from 16.9% at the T1 site to 4.6% at the T2 site and sulfate particles decrease from 35.9% at the T2 site to 15.7% at the T1 site, suggesting that long-range transport air masses experienced more aging processes and produced more secondary particles. Based on our investigations, we proposed that emissions from coal-burning stoves in most rural areas of the west part of Northeast China can induce regional haze episodes.

Charged particle beam scanning using deformed high gradient insulator

Science.gov (United States)

Chen, Yu -Jiuan

2015-10-06

Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

Numerical modeling of aerosol particles scavenging by drops as a process of air depollution

OpenAIRE

Cherrier , Gaël

2017-01-01

This PhD-Thesis is dedicated to the numerical modeling of aerosol particles scavenging by drops. Investigated situations are about aerosol particles of aerodynamic diameter ranging from 1 nm to 100 µm captured in the air by water drops of diameter varying between 80 µm and 600 µm, with corresponding droplet Reynolds number ranging between 1 and 100. This air depollution modeling is achieved in two steps. The first step consists in obtaining a scavenging kernel predicting the flow rate of aero...

Characterization of aerosol particles in a mechanical workshop environment

International Nuclear Information System (INIS)

Matsuyama, S.; Ishii, K.; Yamazaki, H.; Kikuchi, Y.; Fujiwara, M.; Kawamura, Y.; Yamanaka, K.; Watanabe, M.; Tsuboi, S.; Pelicon, P.; Zitnik, M.

2008-01-01

Indoor aerosols are directly affecting human lives. Especially aerosols in workshops, factories, and laboratories, where many chemical substances are used in treatment and production processes, might contain toxic elements: special care must be taken to alleviate air pollution and assure a clean breathing environment for the workers. For this study, size segregated aerosol particle sampling with a cascade impactor was performed in the machine workshop of Jozef Stefan Institute. The samples, collected during weekdays and weekend were analyzed with a microbeam facility at Tohoku University. Bulk PIXE analysis with scanning over the whole sample area was conducted along with multimodal microanalysis with microscopic scanning. Using bulk analysis, high concentrations of Pb and Ba were detected on weekend days, which was related to the removal of an old white paint from the furniture. On weekdays, concentrations of W and of soil origin elements increased, probably because of the machine operations and worker movements. At the same time high concentration of sulfur was detected. A microscopic multimodal analysis shows that it stems from a lubricant oil vapor. The combination of bulk and microanalysis of the size selected samples is an effective approach to aerosol characterization in the working environment. (author)

Geometrical charged-particle optics. 2. ed.

International Nuclear Information System (INIS)

Rose, Harald

2013-01-01

Provides a unique theoretical treatment of charged-particle optics. Displays novel unpublished results on several topics. Provides insight into the properties of charged-particle devices. Treats wave optical properties of the electron. Presents the resolution limit of electron microscopes and novel theoretical treatment of the Stern-Gerlach effect. This second edition is an extended version of the first edition of Geometrical Charged-Particle Optics. The updated reference monograph is intended as a guide for researchers and graduate students who are seeking a comprehensive treatment of the design of instruments and beam-guiding systems of charged particles and their propagation in electromagnetic fields. Wave aspects are included in this edition for explaining electron holography, the Aharanov-Bohm effect and the resolution of electron microscopes limited by diffraction. Several methods for calculating the electromagnetic field are presented and procedures are outlined for calculating the properties of systems with arbitrarily curved axis. Detailed methods are presented for designing and optimizing special components such as aberration correctors, spectrometers, energy filters monochromators, ion traps, electron mirrors and cathode lenses. In particular, the optics of rotationally symmetric lenses, quadrupoles, and systems composed of these elements are discussed extensively. Beam properties such as emittance, brightness, transmissivity and the formation of caustics are outlined. Relativistic motion and spin precession of the electron are treated in a covariant way by introducing the Lorentz-invariant universal time and by extending Hamilton's principle from three to four spatial dimensions where the laboratory time is considered as the fourth pseudo-spatial coordinate. Using this procedure and introducing the self action of the electron, its accompanying electromagnetic field and its radiation field are calculated for arbitrary motion. In addition, the Stern

Diffusivity measurements of volatile organics in levitated viscous aerosol particles

Directory of Open Access Journals (Sweden)

S. Bastelberger

2017-07-01

Full Text Available Field measurements indicating that atmospheric secondary organic aerosol (SOA particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas–particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4 is investigated in an electrodynamic balance at controlled relative humidity (RH and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes–Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH ≲ 30 %, corresponding to diffusivities < 10−14 cm2 s−1 at temperatures < 15 °C. The temperature dependence is strong, suggesting a diffusion activation energy of about 300 kJ mol−1. We conclude that atmospheric volatile organic compounds can be subject to severe diffusion limitations in viscous organic aerosol particles. This may enable an important long-range transport mechanism for organic material, including pollutant molecules such as polycyclic aromatic hydrocarbons (PAHs.

An instrument for the simultaneous acquisition of size, shape, and spectral fluorescence data from single aerosol particles

Science.gov (United States)

Hirst, Edwin; Kaye, Paul H.; Foot, Virginia E.; Clark, James M.; Withers, Philip B.

2004-12-01

We describe the construction of a bio-aerosol monitor designed to capture and record intrinsic fluorescence spectra from individual aerosol particles carried in a sample airflow and to simultaneously capture data relating to the spatial distribution of elastically scattered light from each particle. The spectral fluorescence data recorded by this PFAS (Particle Fluorescence and Shape) monitor contains information relating to the particle material content and specifically to possible biological fluorophores. The spatial scattering data from PFAS yields information relating to particle size and shape. The combination of these data can provide a means of aiding the discrimination of bio-aerosols from background or interferent aerosol particles which may have similar fluorescence properties but exhibit shapes and/or sizes not normally associated with biological particles. The radiation used both to excite particle fluorescence and generate the necessary spatially scattered light flux is provided by a novel compact UV fiber laser operating at 266nm wavelength. Particles drawn from the ambient environment traverse the laser beam in single file. Intrinsic particle fluorescence in the range 300-570nm is collected via an ellipsoidal concentrator into a concave grating spectrometer, the spectral data being recorded using a 16-anode linear array photomultiplier detector. Simultaneously, the spatial radiation pattern scattered by the particle over 5°-30° scattering angle and 360° of azimuth is recorded using a custom designed 31-pixel radial hybrid photodiode array. Data from up to ~5,000 particles per second may be acquired for analysis, usually performed by artificial neural network classification.

Equilibration of particles with abelian charges

International Nuclear Information System (INIS)

Redlich, K.; Tounsi, A.

2002-01-01

We formulate the kinetic equation for time evolution and chemical equilibration of particles that carries an abelian charge. We show that dependently on the thermal conditions inside a fireball the system approaches to different chemical equilibrium limits. The role of exact conservation of quantum numbers in the kinetic description of rarely produced particles is explained. (orig.)

A study of the effect of non-spherical dust particles on Geostationary Environment Monitoring Spectrometer (GEMS) aerosol optical properties retrievals

Science.gov (United States)

Go, S.; Kim, J.; KIM, M.; Choi, M.; Lim, H.

2017-12-01

Non-spherical assumption of particle shape has been used to replace the spherical assumption in the Geostationary Environment Monitoring Spectrometer (GEMS) aerosol optical properties retrievals for dust particles. GEMS aerosol retrieval algorithms are based on optimal estimation method to provide aerosol optical depth (AOD), single scattering albedo (SSA) at 443nm, and aerosol loading height (ALH) simultaneously as products. Considering computing time efficiency, the algorithm takes Look-Up Table (LUT) approach using Vector Linearized Discrete Ordinate Radiative Transfer code (VLIDORT), and aerosol optical properties for three aerosol types of absorbing fine aerosol (BC), dust and non-absorbing aerosol (NA) are integrated from AERONET inversion data, and fed into the LUT calculation. In this study, by applying the present algorithm to OMI top-of the atmosphere normalized radiance, retrieved AOD, SSA with both spherical and non-spherical assumptions have been compared to the surface AERONET observations at East Asia sites for 3 years from 2005 to 2007 to evaluate and quantify the effect of non-spherical dust particles on the satellite aerosol retrievals. The root-mean-square error (RMSE) in the satellite retrieved AOD have been slightly reduced as a result of adopting the non-spherical assumption in the GEMS aerosol retrieval algorithm. For SSA, algorithm tested with spheroid models on dust particle shows promising results for the improved SSA. In terms of ALH, the results are qualitatively compared with CALIOP products, and shows consistent variation. This result suggests the importance of taking into account the effects of non-sphericity in the retrieval of dust particles from GEMS measurements.

Study of particle size distribution and formation mechanism of radioactive aerosols generated in high-energy neutron fields

CERN Document Server

Endo, A; Noguchi, H; Tanaka, S; Iida, T; Furuichi, S; Kanda, Y; Oki, Y

2003-01-01

The size distributions of sup 3 sup 8 Cl, sup 3 sup 9 Cl, sup 8 sup 2 Br and sup 8 sup 4 Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45 MeV and 65 MeV quasi-monoenergetic neutrons were measured in order to study the formation mechanism of radioactive particles in high energy radiation fields. The effects of the size distribution of the radioactive aerosols on the size of the added DOP aerosols, the energy of the neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols. (author)

Clinical physics for charged particle treatment planning

International Nuclear Information System (INIS)

Chen, G.T.Y.; Pitluck, S.; Lyman, J.T.

1981-01-01

The installation of a computerized tomography (CT) scanner which can be used with the patient in an upright position is described. This technique will enhance precise location of tumor position relative to critical structures for accurate charged particle dose delivery during fixed horizontal beam radiotherapy. Pixel-by-pixel treatment planning programs have been developed to calculate the dose distribution from multi-port charged particle beams. The plan includes CT scans, data interpretation, and dose calculations. The treatment planning computer is discussed. Treatment planning for irradiation of ocular melanomas is described

Airborne observations of newly formed boundary layer aerosol particles under cloudy conditions

Directory of Open Access Journals (Sweden)

B. Altstädter

2018-06-01

Full Text Available This study describes the appearance of ultrafine boundary layer aerosol particles under classical non-favourable conditions at the research site of TROPOS (Leibniz Institute for Tropospheric Research. Airborne measurements of meteorological and aerosol properties of the atmospheric boundary layer (ABL were repeatedly performed with the unmanned aerial system ALADINA (Application of Light-weight Aircraft for Detecting IN-situ Aerosol during three seasons between October 2013 and July 2015. More than 100 measurement flights were conducted on 23 different days with a total flight duration of 53 h. In 26 % of the cases, maxima of ultrafine particles were observed close to the inversion layer at altitudes between 400 and 600 m and the particles were rapidly mixed vertically and mainly transported downwards during short time intervals of cloud gaps. This study focuses on two measurement days affected by low-level stratocumulus clouds, but different wind directions (NE, SW and minimal concentrations (< 4.6 µg m−3 of SO2, as a common indicator for precursor gases at ground. Taken from vertical profiles, the onset of clouds led to a non-linearity of humidity that resulted in an increased turbulence at the local-scale and caused fast nucleation e.g., but in relation to rapid dilution of surrounding air, seen in sporadic clusters of ground data, so that ultrafine particles disappeared in the verticality. The typical banana shape of new particle formation (NPF and growth was not seen at ground and thus these days might not have been classified as NPF event days by pure surface studies.

Contribution to the study of nuclear aerosol: looking for the dynamic form factor of the aerosol of primary particles of sodium oxide

International Nuclear Information System (INIS)

Barbe, M.

1982-09-01

The dynamical form factor describes the entrainment of any non spherical particle, of inhomogeneous density, in relation to the entrainment of a spherical particle with the same volume and some sedimentation speed. Experimental study of the form factor and particle size distribution of sodium peroxide primary aerosols [fr

A simplified model of aerosol removal by natural processes in reactor containments

Energy Technology Data Exchange (ETDEWEB)

Powers, D.A.; Washington, K.E.; Sprung, J.L. [Sandia National Labs., Albuquerque, NM (United States); Burson, S.B. [Nuclear Regulatory Commission, Washington, DC (United States)

1996-07-01

Simplified formulae are developed for estimating the aerosol decontamination that can be achieved by natural processes in the containments of pressurized water reactors and in the drywells of boiling water reactors under severe accident conditions. These simplified formulae were derived by correlation of results of Monte Carlo uncertainty analyses of detailed models of aerosol behavior under accident conditions. Monte Carlo uncertainty analyses of decontamination by natural aerosol processes are reported for 1,000, 2,000, 3,000, and 4,000 MW(th) pressurized water reactors and for 1,500, 2,500, and 3,500 MW(th) boiling water reactors. Uncertainty distributions for the decontamination factors and decontamination coefficients as functions of time were developed in the Monte Carlo analyses by considering uncertainties in aerosol processes, material properties, reactor geometry and severe accident progression. Phenomenological uncertainties examined in this work included uncertainties in aerosol coagulation by gravitational collision, Brownian diffusion, turbulent diffusion and turbulent inertia. Uncertainties in aerosol deposition by gravitational settling, thermophoresis, diffusiophoresis, and turbulent diffusion were examined. Electrostatic charging of aerosol particles in severe accidents is discussed. Such charging could affect both the coagulation and deposition of aerosol particles. Electrostatic effects are not considered in most available models of aerosol behavior during severe accidents and cause uncertainties in predicted natural decontamination processes that could not be taken in to account in this work. Median (50%), 90 and 10% values of the uncertainty distributions for effective decontamination coefficients were correlated with time and reactor thermal power. These correlations constitute a simplified model that can be used to estimate the decontamination by natural aerosol processes at 3 levels of conservatism. Applications of the model are described.

Physical characterization of aerosol particles during the Chinese New Year’s firework events

Science.gov (United States)

Zhang, Min; Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Wang, Tao; Yang, Xin; Gong, Youguo; Geng, Fuhai; Chen, Changhong

2010-12-01

Measurements for particles 10 nm to 10 μm were taken using a Wide-range Particle Spectrometer during the Chinese New Year (CNY) celebrations in 2009 in Shanghai, China. These celebrations provided an opportunity to study the number concentration and size distribution of particles in an especial atmospheric pollution situation due to firework displays. The firework activities had a clear contribution to the number concentration of small accumulation mode particles (100-500 nm) and PM 1 mass concentration, with a maximum total number concentration of 3.8 × 10 4 cm -3. A clear shift of particles from nucleation and Aitken mode to small accumulation mode was observed at the peak of the CNY firework event, which can be explained by reduced atmospheric lifetimes of smaller particles via the concept of the coagulation sink. High particle density (2.7 g cm -3) was identified as being particularly characteristic of the firework aerosols. Recalculated fine particles PM 1 exhibited on average above 150 μg m -3 for more than 12 hours, which was a health risk to susceptible individuals. Integral physical parameters of firework aerosols were calculated for understanding their physical properties and further model simulation.

Nanoparticle electrostatic loss within corona needle charger during particle-charging process

International Nuclear Information System (INIS)

Huang Chenghsiung; Alonso, Manuel

2011-01-01

A numerical investigation has been carried out to examine the electrostatic loss of nanoparticles in a corona needle charger. Two-dimensional flow field, electric field, particle charge, and particle trajectory were simulated to obtain the electrostatic deposition loss at different conditions. Simulation of particle trajectories shows that the number of charges per particle during the charging process depends on the particle diameter, radial position from the symmetry axis, applied voltage, Reynolds number, and axial distance along the charger. The numerical results of nanoparticle electrostatic loss agreed fairly well with available experimental data. The results reveal that the electrostatic loss of nanoparticles increases with increasing applied voltage and electrical mobility of particles; and with decreasing particle diameter and Reynolds number. A regression equation closely fitted the obtained numerical results for different conditions. The equation is useful for directly calculating the electrostatic loss of nanoparticles in the corona needle charger during particle-charging process.

Thermal behavior of aerosol particles from biomass burning during the BBOP campaign using transmission electron microscopy

Science.gov (United States)

Adachi, K.; Ishimoto, H.; Sedlacek, A. J., III; Kleinman, L. I.; Chand, D.; Hubbe, J. M.; Buseck, P. R.

2017-12-01

Aerosol samples were collected from wildland and agricultural biomass fires in North America during the 2013 Biomass Burning Observation Project (BBOP). We show in-situ shape and size changes and variations in the compositions of individual particles before and after heating using a transmission electron microscope (TEM). The responses of aerosol particles to heating are important for measurements of their chemical, physical, and optical properties, classification, and determination of origin. However, the thermal behavior of organic aerosol particles is largely unknown. We provide a method to analyze such thermal behavior through heating from room temperature to >600°C by using a heating holder within TEM. The results indicate that individual tar balls (TB; spherical organic material) from biomass burning retained, on average, up to 30% of their volume when heated to 600°C. Chemical analysis reveals that K and Na remained in the residues, whereas S and O were lost. In contrast to bulk sample measurements of carbonaceous particles using thermal/optical carbon analyzers, our single-particle results imply that many individual organic particles consist of multiple types of organic matter having different thermal stabilities. Our results also suggest that because of their thermal stability, some organic particles may not be detectable by using aerosol mass spectrometry or thermal/optical carbon analyzers. This result can lead to an underestimate of the abundance of TBs and other organic particles, and therefore biomass burning may have a greater influence than is currently recognized in regional and global climate models.

Laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF): performance, reference spectra and classification of atmospheric samples

Science.gov (United States)

Shen, Xiaoli; Ramisetty, Ramakrishna; Mohr, Claudia; Huang, Wei; Leisner, Thomas; Saathoff, Harald

2018-04-01

The laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF, AeroMegt GmbH) is able to identify the chemical composition and mixing state of individual aerosol particles, and thus is a tool for elucidating their impacts on human health, visibility, ecosystem, and climate. The overall detection efficiency (ODE) of the instrument we use was determined to range from ˜ (0.01 ± 0.01) to ˜ (4.23 ± 2.36) % for polystyrene latex (PSL) in the size range of 200 to 2000 nm, ˜ (0.44 ± 0.19) to ˜ (6.57 ± 2.38) % for ammonium nitrate (NH4NO3), and ˜ (0.14 ± 0.02) to ˜ (1.46 ± 0.08) % for sodium chloride (NaCl) particles in the size range of 300 to 1000 nm. Reference mass spectra of 32 different particle types relevant for atmospheric aerosol (e.g. pure compounds NH4NO3, K2SO4, NaCl, oxalic acid, pinic acid, and pinonic acid; internal mixtures of e.g. salts, secondary organic aerosol, and metallic core-organic shell particles; more complex particles such as soot and dust particles) were determined. Our results show that internally mixed aerosol particles can result in spectra with new clusters of ions, rather than simply a combination of the spectra from the single components. An exemplary 1-day ambient data set was analysed by both classical fuzzy clustering and a reference-spectra-based classification method. Resulting identified particle types were generally well correlated. We show how a combination of both methods can greatly improve the interpretation of single-particle data in field measurements.

High-LET charged particle radiotherapy

International Nuclear Information System (INIS)

Castro, J.R.; California Univ., San Francisco, CA

1991-07-01

The Department of Radiation Oncology at UCSF Medical Center and the Radiation Oncology Department at UC Lawrence Berkeley Laboratory have been evaluating the use of high LET charged particle radiotherapy in a Phase 1--2 research trial ongoing since 1979. In this clinical trail, 239 patients have received at least 10 Gy (physical) minimum tumor dose with neon ions, meaning that at least one-half of their total treatment was given with high-LET charged particle therapy. Ninety-one patients received all of their therapy with neon ions. Of the 239 patients irradiated, target sites included lesions in the skin, subcutaneous tissues, head and neck such as paranasal sinuses, nasopharynx and salivary glands (major and minor), skull base and juxtaspinal area, GI tract including esophagus, pancreas and biliary tract, prostate, lung, soft tissue and bone. Analysis of these patients has been carried out with a minimum followup period of 2 years

Quantum theory of relativistic charged particles in external fields

International Nuclear Information System (INIS)

Ruijsenaars, S.N.M.

1976-01-01

A study was made on external field theories in which the quantized field corresponds to relativistic elementary particles with non-zero rest mass. These particles are assumed to be charged, thus they have distinct antiparticles. The thesis consists of two parts. The first tries to accommodate the general features of theories of relativistic charged particles in external fields. Spin and dynamics in particular are not specified. In the second part, the results are applied to charged spin-1/2 and spin-0 particles, the dynamics of which are given by the Dirac resp. Klein-Gordon equation. The greater emphasis is on external fields which are rapidly decreasing, infinitely differentiable functions of space-time, but also considers time-independent fields. External fields, other than electromagnetic fields are also considered, e.g. scalar fields

Aerosol number size distributions over a coastal semi urban location: Seasonal changes and ultrafine particle bursts

Energy Technology Data Exchange (ETDEWEB)

Babu, S. Suresh, E-mail: s_sureshbabu@vssc.gov.in [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022 (India); Kompalli, Sobhan Kumar [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022 (India); Moorthy, K. Krishna [Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore 560 012 (India)

2016-09-01

Number-size distribution is one of the important microphysical properties of atmospheric aerosols that influence aerosol life cycle, aerosol-radiation interaction as well as aerosol-cloud interactions. Making use of one-yearlong measurements of aerosol particle number-size distributions (PNSD) over a broad size spectrum (~ 15–15,000 nm) from a tropical coastal semi-urban location-Trivandrum (Thiruvananthapuram), the size characteristics, their seasonality and response to mesoscale and synoptic scale meteorology are examined. While the accumulation mode contributed mostly to the annual mean concentration, ultrafine particles (having diameter < 100 nm) contributed as much as 45% to the total concentration, and thus constitute a strong reservoir, that would add to the larger particles through size transformation. The size distributions were, in general, bimodal with well-defined modes in the accumulation and coarse regimes, with mode diameters lying in the range 141 to 167 nm and 1150 to 1760 nm respectively, in different seasons. Despite the contribution of the coarse sized particles to the total number concentration being meager, they contributed significantly to the surface area and volume, especially during transport of marine air mass highlighting the role of synoptic air mass changes. Significant diurnal variation occurred in the number concentrations, geometric mean diameters, which is mostly attributed to the dynamics of the local coastal atmospheric boundary layer and the effect of mesoscale land/sea breeze circulation. Bursts of ultrafine particles (UFP) occurred quite frequently, apparently during periods of land-sea breeze transitions, caused by the strong mixing of precursor-rich urban air mass with the cleaner marine air mass; the resulting turbulence along with boundary layer dynamics aiding the nucleation. These ex-situ particles were observed at the surface due to the transport associated with boundary layer dynamics. The particle growth rates from

Aerosol number size distributions over a coastal semi urban location: Seasonal changes and ultrafine particle bursts

International Nuclear Information System (INIS)

Babu, S. Suresh; Kompalli, Sobhan Kumar; Moorthy, K. Krishna

2016-01-01

Number-size distribution is one of the important microphysical properties of atmospheric aerosols that influence aerosol life cycle, aerosol-radiation interaction as well as aerosol-cloud interactions. Making use of one-yearlong measurements of aerosol particle number-size distributions (PNSD) over a broad size spectrum (~ 15–15,000 nm) from a tropical coastal semi-urban location-Trivandrum (Thiruvananthapuram), the size characteristics, their seasonality and response to mesoscale and synoptic scale meteorology are examined. While the accumulation mode contributed mostly to the annual mean concentration, ultrafine particles (having diameter < 100 nm) contributed as much as 45% to the total concentration, and thus constitute a strong reservoir, that would add to the larger particles through size transformation. The size distributions were, in general, bimodal with well-defined modes in the accumulation and coarse regimes, with mode diameters lying in the range 141 to 167 nm and 1150 to 1760 nm respectively, in different seasons. Despite the contribution of the coarse sized particles to the total number concentration being meager, they contributed significantly to the surface area and volume, especially during transport of marine air mass highlighting the role of synoptic air mass changes. Significant diurnal variation occurred in the number concentrations, geometric mean diameters, which is mostly attributed to the dynamics of the local coastal atmospheric boundary layer and the effect of mesoscale land/sea breeze circulation. Bursts of ultrafine particles (UFP) occurred quite frequently, apparently during periods of land-sea breeze transitions, caused by the strong mixing of precursor-rich urban air mass with the cleaner marine air mass; the resulting turbulence along with boundary layer dynamics aiding the nucleation. These ex-situ particles were observed at the surface due to the transport associated with boundary layer dynamics. The particle growth rates from

Performance of PC-based charged particle multi-channel spectrometer utilising particle identification

International Nuclear Information System (INIS)

Palla, G.; Sziklai, J.; Trajber, Cs.

1993-12-01

A collaterally expandable charged particle spectrometer based on PC control and particle identification is described. A typical system configuration consisting of two channels are used to test the system performance. (author) 7 refs.; 5 figs

Real-Time Characterization of Aerosol Particle Composition above the Urban Canopy in Beijing: Insights into the Interactions between the Atmospheric Boundary Layer and Aerosol Chemistry.

Science.gov (United States)

Sun, Yele; Du, Wei; Wang, Qingqing; Zhang, Qi; Chen, Chen; Chen, Yong; Chen, Zhenyi; Fu, Pingqing; Wang, Zifa; Gao, Zhiqiu; Worsnop, Douglas R

2015-10-06

Despite extensive efforts into the characterization of air pollution during the past decade, real-time characterization of aerosol particle composition above the urban canopy in the megacity Beijing has never been performed to date. Here we conducted the first simultaneous real-time measurements of aerosol composition at two different heights at the same location in urban Beijing from December 19, 2013 to January 2, 2014. The nonrefractory submicron aerosol (NR-PM1) species were measured in situ by a high-resolution aerosol mass spectrometer at near-ground level and an aerosol chemical speciation monitor at 260 m on a 325 m meteorological tower in Beijing. Secondary aerosol showed similar temporal variations between ground level and 260 m, whereas much weaker correlations were found for the primary aerosol. The diurnal evolution of the ratios and correlations of aerosol species between 260 m and the ground level further illustrated a complex interaction between vertical mixing processes and local source emissions on aerosol chemistry in the atmospheric boundary layer. As a result, the aerosol compositions at the two heights were substantially different. Organic aerosol (OA), mainly composed of primary OA (62%), at the ground level showed a higher contribution to NR-PM1 (65%) than at 260 m (54%), whereas a higher concentration and contribution (15%) of nitrate was observed at 260 m, probably due to the favorable gas-particle partitioning under lower temperature conditions. In addition, two different boundary layer structures were observed, each interacting differently with the evolution processes of aerosol chemistry.

Cell inactivation by heavy charged particles

Energy Technology Data Exchange (ETDEWEB)

Blakely, E A [Lawrence Berkeley Lab., CA (United States). Cell and Molecular Biology Div.

1992-06-01

The inactivation of cells resulting in lethal or aberrant effects by charged particles is of growing interest. Charged particles at extremely high LET are capable of completely eliminating cell-type and cell-line differences in repair capacity. It is still not clear however whether the repair systems are inactivated, or merely that heavy-ion lesions are less repairable. Studies correlating the particle inactivation dose of radioresistant cells with intact DNA analyzed with pulse field gel electrophoresis and other techniques may be useful, but more experiments are also needed to assess the fidelity of repair. For particle irradiations between 40-100 keV/{mu}m there is however evidence for particle-induced activation of specific genes in mammalian cells, and certain repair processes in bacteria. New data are available on the inactivation of developmental processes in several systems including seeds, and cells of the nematode C. elegans. Future experimental and theoretical modeling research emphasis should focus on exploring particle-induced inactivation of endpoints assessing functionality and not just lethality, and on analyzing molecular damage and genetic effects arising in damage but non-inactivated survivors. The discrete nature of selective types of particle damage as a function of radiation quality indicates the value of accelerated ions as probes of normal and aberrant biological processes. Information obtained from molecular analyses of damage and repair must however be integrated into the context of cellular and tissue functions of the organism. (orig.).

Charged particle layers in the Debye limit.

Science.gov (United States)

Golden, Kenneth I; Kalman, Gabor J; Kyrkos, Stamatios

2002-09-01

We develop an equivalent of the Debye-Hückel weakly coupled equilibrium theory for layered classical charged particle systems composed of one single charged species. We consider the two most important configurations, the charged particle bilayer and the infinite superlattice. The approach is based on the link provided by the classical fluctuation-dissipation theorem between the random-phase approximation response functions and the Debye equilibrium pair correlation function. Layer-layer pair correlation functions, screened and polarization potentials, static structure functions, and static response functions are calculated. The importance of the perfect screening and compressibility sum rules in determining the overall behavior of the system, especially in the r--> infinity limit, is emphasized. The similarities and differences between the quasi-two-dimensional bilayer and the quasi-three-dimensional superlattice are highlighted. An unexpected behavior that emerges from the analysis is that the screened potential, the correlations, and the screening charges carried by the individual layers exhibit a marked nonmonotonic dependence on the layer separation.

Charged particle layers in the Debye limit

International Nuclear Information System (INIS)

Golden, Kenneth I.; Kalman, Gabor J.; Kyrkos, Stamatios

2002-01-01

We develop an equivalent of the Debye-Hueckel weakly coupled equilibrium theory for layered classical charged particle systems composed of one single charged species. We consider the two most important configurations, the charged particle bilayer and the infinite superlattice. The approach is based on the link provided by the classical fluctuation-dissipation theorem between the random-phase approximation response functions and the Debye equilibrium pair correlation function. Layer-layer pair correlation functions, screened and polarization potentials, static structure functions, and static response functions are calculated. The importance of the perfect screening and compressibility sum rules in determining the overall behavior of the system, especially in the r→∞ limit, is emphasized. The similarities and differences between the quasi-two-dimensional bilayer and the quasi-three-dimensional superlattice are highlighted. An unexpected behavior that emerges from the analysis is that the screened potential, the correlations, and the screening charges carried by the individual layers exhibit a marked nonmonotonic dependence on the layer separation

Time evolution and emission factors of aerosol particles from day and night time savannah fires

Science.gov (United States)