WorldWideScience

Sample records for airborne particles generated

  1. Airborne soil organic particles generated by precipitation

    Science.gov (United States)

    Wang, Bingbing; Harder, Tristan H.; Kelly, Stephen T.; Piens, Dominique S.; China, Swarup; Kovarik, Libor; Keiluweit, Marco; Arey, Bruce W.; Gilles, Mary K.; Laskin, Alexander

    2016-06-01

    Airborne organic particles play a critical role in Earth's climate, public health, air quality, and hydrological and carbon cycles. However, sources and formation mechanisms for semi-solid and solid organic particles are poorly understood and typically neglected in atmospheric models. Laboratory evidence suggests that fine particles can be formed from impaction of mineral surfaces by droplets. Here, we use chemical imaging of particles collected following rain events in the Southern Great Plains, Oklahoma, USA and after experimental irrigation to show that raindrop impaction of soils generates solid organic particles. We find that after rain events, sub-micrometre solid particles, with a chemical composition consistent with soil organic matter, contributed up to 60% of atmospheric particles. Our irrigation experiments indicate that intensive water impaction is sufficient to cause ejection of airborne soil organic particles from the soil surface. Chemical imaging and micro-spectroscopy analysis of particle physico-chemical properties suggest that these particles may have important impacts on cloud formation and efficiently absorb solar radiation. We suggest that raindrop-induced formation of solid organic particles from soils may be a widespread phenomenon in ecosystems such as agricultural systems and grasslands where soils are exposed to strong, episodic precipitation events.

  2. Study of airborne particles generated by the impact of droplets

    International Nuclear Information System (INIS)

    A liquid droplet impinging onto surfaces occurs in many industrial and natural processes. The study of this phenomenon is fundamental in order to determine the potential sources of contamination in the case of scenarios of liquid falls such as dripping. There are very few data in the literature in the case of the impact of millimeter-size droplets. The purpose of our work is to study experimentally the particle emission during the impact of droplets onto a liquid film. Experiments were conducted to study the influence of the velocity and the diameter of the droplets, the height of the liquid film, the surface tension and viscosity of the liquid on the airborne particles. Our results, original, have made it possible to examine the relevance of existing relations, describing the transition between deposition and splash regimes, in order to determine the presence or not of airborne particles. The micro droplets produced, with diameters less than fifty micrometers, are characterised in terms of total mass and size distribution. Our results also show the influence of a combination of several factors on the production of airborne particles. For this reason, it is interesting to use dimensionless numbers, to describe the relationship between the inertial, viscosity and surface tension forces, in order to understand physically the emission of airborne particles. (author)

  3. Study of airborne particle generated by free falling powder

    International Nuclear Information System (INIS)

    This study comes within the general framework of industrial facilities' safety research. Indeed, industrial processes, notably in the nuclear field, handle hazardous materials in powder form and can produce large quantities of fugitive dust. The study of the particles resuspension from powders is of interest of first order in order to estimate the consequences of this source term of contamination on the operator, the neighbouring installations and, if necessary, the environment. Up to now, there are very few reliable data in the scientific literature on the particulate emission in case of a scenario with an accidental free fall spill of powder. The powder dustiness evaluation is carried out using coefficients obtained in experiments, or using empirical correlations. The objective of the present work is to study the influence of some parameters involved in the airborne particles production by a free fall of powder. For that purpose, experiments are carried out in order to study the influence of parameters such as the type of discharge, the powder nature, the type of surface on which occurs the powder impaction, the system diameter used for discharge, and the falling mass. The results of mass fractions and number concentrations obtained highlighted the dominating parameters according to the type of discharge employed. Thereafter, the comparisons between our results and the empirical correlations available in the literature showed that those led to an undervaluation of the powder dustiness. This thus led us to develop, starting from the whole of experimental data, empirical correlations taking into account the various parameters studied as well as the interactions. (author)

  4. Effect of indoor-generated airborne particles on radon progeny dynamics.

    Science.gov (United States)

    Trassierra, C Vargas; Stabile, L; Cardellini, F; Morawska, L; Buonanno, G

    2016-08-15

    In order to investigate the interaction between radon progeny and particles, an experimental campaign was carried out in a radon chamber at the Italian National Institute of Ionizing Radiation Metrology, quantifying the amount of attached and unattached radon daughters present in air, as well as the equilibrium factor in the presence of particles generated through indoor sources. A fixed radon concentration was maintained, while particles were generated using incense sticks, mosquito coils and gas combustion. Aerosols were characterized in terms of particle concentrations and size distributions. Simultaneously, radon concentration and attached/unattached potential alpha energy concentration in the air were continuously monitored by two different devices, based on alpha spectroscopy techniques. The presence of particles was found to affect the attached fraction of radon decay products, in such a way that the particles acted as a sink for radionuclides. In terms of sources which emit large particles (e.g. incense, mosquito coils), which greatly increase particle surface area concentrations, the Equilibrium Factor was found to double with respect to the background level before particle generation sessions. On the contrary, the radon decay product dynamics were not influenced by gas combustion processes, mainly due to the small surface area of the particles emitted. PMID:27131455

  5. The impact of fireworks on airborne particles

    OpenAIRE

    R. Vecchi; Bernardoni, V.; Cricchio, D; A. D'Alessandro; P. Fermo; F. Lucarelli(Agenzia Spaziale Italiana); S. Nava; Piazzalunga, A.; Valli, G.

    2008-01-01

    Fireworks are one of the most unusual sources of pollution in atmosphere; although transient, these pollution episodes are responsible for high concentrations of particles (especially metals and organic compounds) and gases. In this paper, results of a study on chemical-physical properties of airborne particles (elements, ions, organic and elemental carbon and particles size distributions) collected during a fireworks episode in Milan (Italy) are reported. Elements typically emitted during py...

  6. Evaluation of airborne particle emissions from commercial products containing carbon nanotubes

    International Nuclear Information System (INIS)

    The emission of the airborne particles from epoxy resin test sticks with different carbon nanotube (CNT) loadings and two commercial products were characterized while sanding with three grit sizes and three disk sander speeds. The total number concentrations, respirable mass concentrations, and particle size number/mass distributions of the emitted particles were measured using a condensation particle counter, an optical particle counter, and a scanning mobility particle sizer. The emitted particles were sampled on a polycarbonate filter and analyzed using electron microscopy. The highest number concentrations (arithmetic mean = 4,670 particles/cm3) were produced with coarse sandpaper, 2 % (by weight) CNT test sticks and medium disk sander speed, whereas the lowest number concentrations (arithmetic mean = 92 particles/cm3) were produced with medium sandpaper, 2 % CNT test sticks and slow disk sander speed. Respirable mass concentrations were the highest (arithmetic mean = 1.01 mg/m3) for fine sandpaper, 2 % CNT test sticks and medium disk sander speed and the lowest (arithmetic mean = 0.20 mg/m3) for medium sandpaper, 0 % CNT test sticks and medium disk sander speed. For CNT-epoxy samples, airborne particles were primarily micrometer-sized epoxy cores with CNT protrusions. No free CNTs were observed in airborne samples, except for tests conducted with 4 % CNT-epoxy. The number concentration, mass concentration, and size distribution of airborne particles generated when products containing CNTs are sanded depends on the conditions of sanding and the characteristics of the material being sanded.

  7. The Next Generation Airborne Polarimetric Doppler Radar

    Science.gov (United States)

    Vivekanandan, J.; Lee, Wen-Chau; Loew, Eric; Salazar, Jorge; Chandrasekar, V.

    2013-04-01

    NCAR's Electra Doppler radar (ELDORA) with a dual-beam slotted waveguide array using dual-transmitter, dual-beam, rapid scan and step-chirped waveform significantly improved the spatial scale to 300m (Hildebrand et al. 1996). However, ELDORA X-band radar's penetration into precipitation is limited by attenuation and is not designed to collect polarimetric measurements to remotely estimate microphysics. ELDORA has been placed on dormancy because its airborne platform (P3 587) was retired in January 2013. The US research community has strongly voiced the need to continue measurement capability similar to the ELDORA. A critical weather research area is quantitative precipitation estimation/forecasting (QPE/QPF). In recent years, hurricane intensity change involving eye-eyewall interactions has drawn research attention (Montgomery et al., 2006; Bell and Montgomery, 2006). In the case of convective precipitation, two issues, namely, (1) when and where convection will be initiated, and (2) determining the organization and structure of ensuing convection, are key for QPF. Therefore collocated measurements of 3-D winds and precipitation microphysics are required for achieving significant skills in QPF and QPE. Multiple radars in dual-Doppler configuration with polarization capability estimate dynamical and microphysical characteristics of clouds and precipitation are mostly available over land. However, storms over complex terrain, the ocean and in forest regions are not observable by ground-based radars (Bluestein and Wakimoto, 2003). NCAR/EOL is investigating potential configurations for the next generation airborne radar that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. ELDORA's slotted waveguide array radar is not compatible for dual-polarization measurements. Therefore, the new design has to address both dual-polarization capability and platform requirements to replace the ELDORA system. NCAR maintains a C-130

  8. Acoustic Resonator Optimisation for Airborne Particle Manipulation

    Science.gov (United States)

    Devendran, Citsabehsan; Billson, Duncan R.; Hutchins, David A.; Alan, Tuncay; Neild, Adrian

    Advances in micro-electromechanical systems (MEMS) technology and biomedical research necessitate micro-machined manipulators to capture, handle and position delicate micron-sized particles. To this end, a parallel plate acoustic resonator system has been investigated for the purposes of manipulation and entrapment of micron sized particles in air. Numerical and finite element modelling was performed to optimise the design of the layered acoustic resonator. To obtain an optimised resonator design, careful considerations of the effect of thickness and material properties are required. Furthermore, the effect of acoustic attenuation which is dependent on frequency is also considered within this study, leading to an optimum operational frequency range. Finally, experimental results demonstrated good particle levitation and capture of various particle properties and sizes ranging to as small as 14.8 μm.

  9. SIZE DISTRIBUTION AND RATE OF PRODUCTION OF AIRBORNE PARTICULATE MATTER GENERATED DURING METAL CUTTING

    International Nuclear Information System (INIS)

    During deactivation and decommissioning activities, thermal cutting tools, such as plasma torch, laser, and gasoline torch, are used to cut metals. These activities generate fumes, smoke and particulates. These airborne species of matter, called aerosols, may be inhaled if suitable respiratory protection is not used. Inhalation of the airborne metallic aerosols has been reported to cause ill health effects, such as acute respiratory syndrome and chromosome damage in lymphocytes. In the nuclear industry, metals may be contaminated with radioactive materials. Cutting these metals, as in size reduction of gloveboxes and tanks, produces high concentrations of airborne transuranic particles. Particles of the respirable size range (size < 10 microm) deposit in various compartments of the respiratory tract, the fraction and the site in the respiratory tract depending on the size of the particles. The dose delivered to the respiratory tract depends on the size distribution of the airborne particulates (aerosols) and their concentration and radioactivity/toxicity. The concentration of airborne particulate matter in an environment is dependent upon the rate of their production and the ventilation rate. Thus, measuring aerosol size distribution and generation rate is important for (1) the assessment of inhalation exposures of workers, (2) the selection of respiratory protection equipment, and (3) the design of appropriate filtration systems. Size distribution of the aerosols generated during cutting of different metals by plasma torch was measured. Cutting rates of different metals, rate of generation of respirable mass, as well as the fraction of the released kerf that become respirable were determined. This report presents results of these studies. Measurements of the particles generated during cutting of metal plates with a plasma arc torch revealed the presence of particles with mass median aerodynamic diameters of particles close to 0.2 micro

  10. [Investigation of Carbonaceous Airborne Particles by Scanning Proton Microprobe].

    Science.gov (United States)

    Bao, Liang-man; Liu, Jiang-feng; Lei, Qian-tao; Li, Xiao-lin; Zhang, Gui-lin; Li, Yan

    2016-01-15

    Carbonaceous particles are an important component of the atmospheric aerosol particles and important for global climate change, air quality and human health. The PM₁₀ single particles from two environmental monitor locations and seven pollution emission sources were analyzed using scanning proton microprobe (SPM) techniques. The concentration of carbon in individual particles was quantitatively determined by proton non-Rutherford elastic backscattering spectrometry (EBS). The results of this investigation showed that carbonaceous particles were dominant in the pollution sources of coal and oil combustions, diesel busexhaust and automobile exhaust, while inorganic particles were dominant in the sources of steel industry, cement dust and soil dust. Carbonaceous matter was enriched in particles from the city center, while mineral matter was the main component of airborne particles in the industrial area. Elemental mapping of single aerosol particles yielded important information on the chemical reactions of aerosol particles. The micro-PIXE (particle induced X-ray emission) maps of S, Ca and Fe of individual carbonaceous particles showed that sulfuration reaction occurred between SO₂and mineral particles, which increased the sulfur content of particles. PMID:27078933

  11. Radioactive airborne particles from Chernobyl forest fires

    International Nuclear Information System (INIS)

    The spring and summer, 1992 within 30-km zone near Chernobyl NPP were very hot and dry. That lead to forest fires in May (4 ... 9,23 ... 25), July (28 ... 30) and August (10...12). The Cs-137 soil contamination density (SCD) was equal to 1...400 Ci/km2 at various forest sections of combustion. The stationary air samplers with capacity of 1500 m3/h were used for the monitoring of aerosol emissions during fires. These samplers were situated at a distance of 5...10km from fires boundaries. Smoke particles were collected by the fibrous filters FPP-15-1,5 (Russia). After exposure the activity of aerosols of Cs which deposited by a filter was measured by a gamma-spectrometer. For the separation of Sr-90 and isotopes of Pu the radiochemical analysis was used. It was found that the concentration of Cs-137 increased up to 10...100 times compare with open-quotes backgroundclose quotes one even at several km from fires. The concentration of Cs-137 inside of combustion zone was estimated could exceed the Russian maximum permissible one both for population (0.49 nCi/m3) and for professionals (14 nCi/m3) if the SCD will be more than 0.5 and 7 Ci/km2, respectively. It was measured that Cs-137/Sr-90 and Cs-137/Pu-238 ratios increase in fire emissions. It is obviously, that such enrichment was a consequense of radioactive cesium evaporation at temperature more than 500 C. The experimental forest fire was carry out in August, 1993 in Bryansk region (Russia). The forest section with area 50x50 m was selected. The SCD of Cs-137 was equal to 30 Ci/km2. The Cs-137 concentration during the day before the experiment was equal to 0.16pCi/m3. The concentration was varied from 1.6 to 15 pCi/m3 during the experiment. For the determination of particle sizes the filter pack technique (Budyka et al, 1993) was used. It was found that particle size distribution was a bimodal in plume

  12. New Methods for Personal Exposure Monitoring for Airborne Particles.

    Science.gov (United States)

    Koehler, Kirsten A; Peters, Thomas M

    2015-12-01

    Airborne particles have been associated with a range of adverse cardiopulmonary outcomes, which has driven its monitoring at stationary central sites throughout the world. Individual exposures, however, can differ substantially from concentrations measured at central sites due to spatial variability across a region and sources unique to the individual, such as cooking or cleaning in homes, traffic emissions during commutes, and widely varying sources encountered at work. Personal monitoring with small, battery-powered instruments enables the measurement of an individual's exposure as they go about their daily activities. Personal monitoring can substantially reduce exposure misclassification and improve the power to detect relationships between particulate pollution and adverse health outcomes. By partitioning exposures to known locations and sources, it may be possible to account for variable toxicity of different sources. This review outlines recent advances in the field of personal exposure assessment for particulate pollution. Advances in battery technology have improved the feasibility of 24-h monitoring, providing the ability to more completely attribute exposures to microenvironment (e.g., work, home, commute). New metrics to evaluate the relationship between particulate matter and health are also being considered, including particle number concentration, particle composition measures, and particle oxidative load. Such metrics provide opportunities to develop more precise associations between airborne particles and health and may provide opportunities for more effective regulations. PMID:26385477

  13. Inversely tracking indoor airborne particles to locate their release sources

    Science.gov (United States)

    Zhang, Tengfei (Tim); Li, Hongzhu; Wang, Shugang

    2012-08-01

    Airborne particles can have numerous adverse effects on human health. Knowing the release locations of airborne particulate sources is helpful in minimizing pollutant exposure. This paper describes a proposal to locate indoor particulate sources by two inverse models: the quasi-reversibility (QR) model and the zone prescription of contaminant sources with the Lagrangian-reversibility (LR) model. The QR model reverses the time marching direction of the Eulerian governing equation and replaces the second-order diffusion term with a fourth-order stabilization term. The zone prescription LR model traces individual particulate motion in a Lagrangian reference frame after reversing the flow field. The particle trajectories are solved backward to the initial release once the conservative forces acting on particles are reversed. The tracked particles are proposed to be placed at the zone boundary of the largest concentration contour within the domain at a given time, which is provided as the initially known information. By connecting all particles at t = 0, a zone is formed that can prescribe the actual contaminant source. This study finds that both models can accurately locate particulate sources released instantaneously at a spot. The QR model performs slightly better than the LR model but is much more computationally demanding.

  14. Particle sizing of airborne radioactivity field measurements at Olympic Dam

    International Nuclear Information System (INIS)

    On July 1, 1991 the Australian Radiation Laboratory (ARL) commenced a two year project entitled - Particle sizing of airborne radioactivity, funded by a Mining and Quarrying Occupational Health and Safety Committee - grant (submission No. 9138). This study was set out to measure airborne radioactivity size distributions in an underground uranium mine, in order to provide better estimates of the health risks associated with inhalation of airborne radiation in the work place. These measurements included both active and passive measurement of radon gas, continuous and spot sample of radon daughter levels, as well as wire screen diffusion battery measurements of the radon daughter size distributions. The results of measurements at over 50 sites within the mine are reported, together with the calculated dose conversion factors derived from the older dosimetric models and from the new ICRP lung model using the computer code RADEP. The results showed that the ventilation is relatively uniform within the mine and the radon daughter concentrations are kept to less than 20% of the equilibrium concentration. The radon and radon daughter concentrations showed marked variability with both time and position within the mine. It is concluded that the present radiation protection methods and dose conversion factors used in Australia provide a good estimate of the radiation risk for the inhalation of radon progeny. 29 refs., 8 tabs., 9 figs

  15. Microvolumetric determination of inorganic and organic sulphur in airborne particles

    Energy Technology Data Exchange (ETDEWEB)

    Moehnle, K.; Krivan, V.; Grallath, E.

    1984-02-01

    A reductive procedure for the determination of sulphur was modified and applied to the analysis of airborne particles. It is based on the reduction of the given sulphur forms with the mixture HI/HCOOH/H/sub 3/PO/sub 2//Sb/sub 2/O/sub 3/ to hydrogen sulphide, which is transferred into a NaOH solution and determined by microtitration with Cd/sup 2 +/ using dithizone as indicator. Examination of the behaviour of the different sulphur forms in the reduction mixture showed that the inorganic sulphur was converted to H/sub 2/S whereas the organic remained in the reaction flask. This makes possible the differentiation between inorganic and organic sulphur when one part of the sample is directly reacted with the mixture and the other one is oxidatively decomposed (Schoeniger), and then the total sulphur determined with the same procedure. The method was used for the analysis of a number of airborne particle samples of different origin, and the results were compared with those of some instrumental techniques.

  16. Characterization and Control of Airborne Particles Emitted During Production of Epoxy / Carbon Nanotube Nanocomposites

    Science.gov (United States)

    Cena, Lorenzo G.; Peters, Thomas M.

    2016-01-01

    This work characterized airborne particles that were generated from the weighing of bulk, multi-wall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratiô1). The particles generated during sanding were predominately micron-sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 μm) tangled clusters. Respirable mass concentrations in the operator’s breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 μg/m3) compared to those with no LEV (GM = 2.68 μg/m3) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m3; p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec). PMID:21253981

  17. Measurement of airborne particle concentrations near the Sunset Crater volcano, Arizona.

    Science.gov (United States)

    Benke, Roland R; Hooper, Donald M; Durham, James S; Bannon, Donald R; Compton, Keith L; Necsoiu, Marius; McGinnis, Ronald N

    2009-02-01

    Direct measurements of airborne particle mass concentrations or mass loads are often used to estimate health effects from the inhalation of resuspended contaminated soil. Airborne particle mass concentrations were measured using a personal sampler under a variety of surface-disturbing activities within different depositional environments at both volcanic and nonvolcanic sites near the Sunset Crater volcano in northern Arizona. Focused field investigations were performed at this analog site to improve the understanding of natural and human-induced processes at Yucca Mountain, Nevada. The level of surface-disturbing activity was found to be the most influential factor affecting the measured airborne particle concentrations, which increased over three orders of magnitude relative to ambient conditions. As the surface-disturbing activity level increased, the particle size distribution and the majority of airborne particle mass shifted from particles with aerodynamic diameters less than 10 mum (0.00039 in) to particles with aerodynamic diameters greater than 10 mum (0.00039 in). Under ambient conditions, above average wind speeds tended to increase airborne particle concentrations. In contrast, stronger winds tended to decrease airborne particle concentrations in the breathing zone during light and heavy surface-disturbing conditions. A slight increase in the average airborne particle concentration during ambient conditions was found above older nonvolcanic deposits, which tended to be finer grained than the Sunset Crater tephra deposits. An increased airborne particle concentration was realized when walking on an extremely fine-grained deposit, but the sensitivity of airborne particle concentrations to the resuspendible fraction of near-surface grain mass was not conclusive in the field setting when human activities disturbed the bulk of near-surface material. Although the limited sample size precluded detailed statistical analysis, the differences in airborne particle

  18. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit

    Science.gov (United States)

    Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J.; Banfield, Jillian F.; Nazaroff, William W.

    2016-01-01

    Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses’ station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3–1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3–10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37–81%. Near-room indoor emissions and outdoor sources contributed 18–59% and 1–5%, respectively. Airborne particle levels in the size range 1–10 μm showed strong dependence on human activities, indicating the importance of indoor-generated

  19. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit.

    Directory of Open Access Journals (Sweden)

    Dusan Licina

    Full Text Available Premature infants in neonatal intensive care units (NICUs have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses' station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3-1 μm particles. The mean indoor particle mass concentrations averaged across the size range 0.3-10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3. Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37-81%. Near-room indoor emissions and outdoor sources contributed 18-59% and 1-5%, respectively. Airborne particle levels in the size range 1-10 μm showed strong dependence on human activities, indicating the importance of indoor-generated

  20. An introduction to data analysis of airborne particle composition

    International Nuclear Information System (INIS)

    A major problem facing air quality management personnel is the identification of sources of airborne particles and the quantitative apportionment of the aerosol mass to those sources. The ability to collect particle samples and analyze these samples for a suite of elements by such techniques as neutron activation analysis or x-ray fluorescence provides that data for the problem of resolving a series of complex mixtures into its components based on the profiles of the elements emitted by the various sources in the airshed. If all of the sources and their composition profiles are known, then the mass balance model becomes a multiple regression problem. If a series of samples have been analyzed without substantial information being available on the sources, factor analysis methods can be employed. In both situations, there are limits to the identification of specific sources or the location of the sources. Thus, other methods that combine chemical with meteorological data have been developed to assist in spatial identification of pollutant sources. There are also limitations to the ability of any statistical method to resolve sources in real world problems. The physical and statistical basis of these methods and their application to representative problems are reviewed in this report. (author). 42 refs, 5 figs, 5 tabs

  1. A microfluidics-based on-chip impinger for airborne particle collection.

    Science.gov (United States)

    Mirzaee, I; Song, M; Charmchi, M; Sun, H

    2016-06-21

    Capturing airborne particles from air into a liquid is a critical process for the development of many sensors and analytical systems. A miniaturized airborne particle sampling device (microimpinger) has been developed in this research. The microimpinger relies on a controlled bubble generation process produced by driving air through microchannel arrays. The particles confined in the microscale bubbles are captured in the sampling liquid while the bubbles form, are released and travel in a millimetre-scale sealed liquid reservoir. The microchannel arrays in the impinger are fabricated using a soft-lithography method with polydimethylsiloxane (PDMS) as the structural material. To prevent air leakage at the connections, a PDMS-only sealing technique is successfully developed. The hydrophobicity of the microchannel surface is found to be critical for generating continuous and stable bubbles in the bubbling process. A Teflon layer is coated on the walls of a microchannel array by vapor deposition which effectively increases the hydrophobicity of the PDMS. The collection efficiency of the microimpinger is measured by counting different sizes of fluorescent polystyrene latex particles on polycarbonate membrane filters. Collection efficiencies above 90% are achieved. Furthermore, the particle capturing mechanisms during the injection, formation and rise of a single microbubble are investigated by a computational fluid dynamics (CFD) model. The Navier-Stokes equations are solved along with the use of the volume-of-fluid (VOF) method to capture the bubble deformations and the particles are tracked using a Lagrangian equation of motion. The model is also employed to study the effect of bubble size on the collection efficiency of the microimpinger. PMID:27185303

  2. System considerations for airborne, high power superconducting generators

    International Nuclear Information System (INIS)

    The design of rotating superconducting field windings in high power generators is greatly influenced by system considerations. Experience with two superconducting generators designed to produce 5 and 20 Mw resulted in a number of design restrictions. The design restrictions imposed by system considerations have not prevented low weight and high voltage power generation capability. The application of multifilament Nb;sub 3;Sn has permitted a large thermal margin to be designed into the rotating field winding. This margin permits the field winding to remain superconducting under severe system operational requirements. System considerations include: fast rotational startup, fast ramped magnetic fields, load induced transient fields and airborne cryogen logistics. Preliminary selection of a multifilament Nb;sub 3;Sn cable has resulted from these considerations. The cable will carry 864 amp at 8.5K and 6.8 Tesla. 10 refs

  3. Measurement of the electrostatic charge in airborne particles: II - particle charge distribution of different aerosols

    Directory of Open Access Journals (Sweden)

    M. V. Rodrigues

    2006-03-01

    Full Text Available This work gives sequence to the study on the measurement of the electrostatic charges in aerosols. The particle charge classifier developed for this purpose and presented in the previous paper (Marra and Coury, 2000 has been used here to measure the particle charge distribution of a number of different aerosols. The charges acquired by the particles were naturally derived from the aerosol generation procedure itself. Two types of aerosol generators were used: the vibrating orifice generator and turntable Venturi plate generator. In the vibrating orifice generator, mono-dispersed particles were generated by a solution of water/ethanol/methylene blue, while in the rotating plate generator, six different materials were utilized. The results showed no clear dependence between electric charge and particle diameter for the mono-dispersed aerosol. However, for the poly-dispersed aerosols, a linear dependence between particle size and charge could be noticed.

  4. Determination of thorium and uranium particles in monazite airborne

    International Nuclear Information System (INIS)

    The work is the determination of the Mass Median Aerodynamic Diameter of Airborne particles of Th and U, produced during the milling of monazite in Monozite Sand Plants. The air samples was collected using a Cascade Impactor from Delron DCI-6 with a flux of 12,5 1/min and cut-off diametes of 0,5, 1,0, 4,0, 8,0 and 16,0 μm. Each stage of the cascate impactor was analysed by measuring the X rays induced in collision with 2 MeV protons acellereted by a 4 MV Van de Graaff acceletor located at University Catolic, PUC, RJ. The MMAD found for Th and U was of 1,15 μm with a geometric standard desviation of 2,0. Take in acount that there are more thorium than uranium in the brazilian monazite, and the 232Th 238U are thr principal isotopes at the Th and U natural radioative decay series, we considered the mass and the activity distribution as equal. The mean concentration of Th (17,0 Bq/m3) record in the air was 42% above 3/10 of international limit for concentration of oxides of thorium in the air, while the concentration of U remaind below 1/10 of the limit for concentration of U3O8 in the air. (author)

  5. Trapped particles and harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, Jr, W E; DeGroot, J S

    1977-01-01

    A novel fluid-particle algorithm has been used to study the evolution of continuously generated ion acoustic waves numerically. The code permits the simultaneous analysis of the two nonlinearities involved: wave steepening or harmonic generation, a fluid effect; and wave damping and amplitude oscillations, a particle effect. For a temperature ratio 10 < T/sub e//T/sub i/ < 30, the behavior of low amplitude long wavelength waves is well described by a Korteweg-deVries equation augmented to include a time dependent damping term.

  6. Discussion on National Standard GB 6167 "Methods for Testing the Performance of Airborne Particle Counter"

    Institute of Scientific and Technical Information of China (English)

    刘俊杰; 朱能; 王君山

    2003-01-01

    Airborne particle counters are used widely to test the air cleanliness of cleanrooms. The current Chinese national standard of airborne particle counter calibration, GB6167-85, Methods for Testing the Performance of Dust Particle Counter, has kept the same for more than 10 years. It is necessary to be amended in time.This paper discusses the differences between Chinese airborne particle counter calibration procedure and other new calibration procedures in other countries, and points out the defects of current Chinese national standard.The draft of revised Chinese National Standard is also introduced. The new revised standard, Methods for Testing the Performance of Airborne Particle Counter, covers two level calibrations:primary and secondary. Primary calibration procedure includes testing 6 kinds of performances: sample airflow rate, false counting, particle size accuracy and resolution, particle counting stability, counting efficiency and particle concentration limit. Secondary calibration is a relative comparing test method to verify the counting accuracy of calibrated airborne particle counters. Finally, how to keep the calibration traceability is suggested.

  7. Self-refreshing characteristics of an airborne particle sensor using a bridged paddle oscillator

    Science.gov (United States)

    Choi, Eunsuk; Lee, Seung-Beck; Park, Bonghyun; Sul, Onejae

    2016-05-01

    We report on the self-refreshing characteristics of a micromachined airborne particle sensor. The sensor consists of a bridge-type beam having an oscillating paddle-type particle collector at its center. When a positive potential is applied to the paddle, the sensor is able to attract and collect negatively charged airborne particles while oscillating close to its resonant frequency and thereby measure their density from the change in the oscillating phase at ˜10 pg resolution. When the applied potential is removed, the collected particles are detached from the sensor due to momentum transfer from the oscillating paddle, thus demonstrating a self-refreshing capability.

  8. A new look at inhalable metalliferous airborne particles on rail subway platforms.

    Science.gov (United States)

    Moreno, Teresa; Martins, Vânia; Querol, Xavier; Jones, Tim; BéruBé, Kelly; Minguillón, Maria Cruz; Amato, Fulvio; Capdevila, Marta; de Miguel, Eladio; Centelles, Sonia; Gibbons, Wes

    2015-02-01

    Most particles breathed on rail subway platforms are highly ferruginous (FePM) and extremely small (nanometric to a few microns in size). High magnification observations of particle texture and chemistry on airborne PM₁₀ samples collected from the Barcelona Metro, combined with published experimental work on particle generation by frictional sliding, allow us to propose a general model to explain the origin of most subway FePM. Particle generation occurs by mechanical wear at the brake-wheel and wheel-rail interfaces, where magnetic metallic flakes and splinters are released and undergo progressive atmospheric oxidation from metallic iron to magnetite and maghemite. Flakes of magnetite typically comprise mottled mosaics of octahedral nanocrystals (10-20 nm) that become pseudomorphed by maghemite. Continued oxidation results in extensive alteration of the magnetic nanostructure to more rounded aggregates of non-magnetic hematite nanocrystals, with magnetic precursors (including iron metal) still preserved in some particle cores. Particles derived from steel wheel and rails contain a characteristic trace element chemistry, typically with Mn/Fe=0.01. Flakes released from brakes are chemically very distinctive, depending on the pad composition, being always carbonaceous, commonly barium-rich, and texturally inhomogeneous, with trace elements present in nanominerals incorporated within the crystalline structure. In the studied subway lines of Barcelona at least there appears to be only a minimal aerosol contribution from high temperature processes such as sparking. To date there is no strong evidence that these chemically and texturally complex inhalable metallic materials are any more or less toxic than street-level urban particles, and as with outdoor air, the priority in subway air quality should be to reduce high mass concentrations of aerosol present in some stations. PMID:25461038

  9. Bioaerosol Mass Spectrometry for Rapid Detection of Individual Airborne Mycobacterium tuberculosis H37Ra Particles

    OpenAIRE

    Tobias, Herbert J.; Schafer, Millie P.; Pitesky, Maurice; Fergenson, David P.; Horn, Joanne; Frank, Matthias; Gard, Eric E.

    2005-01-01

    Single-particle laser desorption/ionization time-of-flight mass spectrometry, in the form of bioaerosol mass spectrometry (BAMS), was evaluated as a rapid detector for individual airborne, micron-sized, Mycobacterium tuberculosis H37Ra particles, comprised of a single cell or a small number of clumped cells. The BAMS mass spectral signatures for aerosolized M. tuberculosis H37Ra particles were found to be distinct from M. smegmatis, Bacillus atrophaeus, and B. cereus particles, using a distin...

  10. Airborne contamination of forest soils by carbonaceous particles from industrial coal processing

    OpenAIRE

    Schmidt, M. W. I.; Knicker, Heike; Hatcher, Patrick G.; Kögel-Knabner, I.

    2000-01-01

    In the German Ruhr-area industrial coal processing emitted large amounts of carbonaceous particles for a century until 1970. Our objectives were to detect the presence of airborne carbonaceous particles and assess their impact on the chemical structure of soil organic matter in two forest soils (Podzols) with potential sources of carbonaceous particles approximately 10 to 30 km away. Contamination was not visible macroscopicaily. Organic matter was characterized in bulk soils and in particle-...

  11. ELECTROHYDRODYNAMIC ENHANCED TRANSPORT AND TRAPPING OF AIRBORNE PARTICLES TO A MICROFLUIDIC AIR-LIQUID INTERFACE

    OpenAIRE

    Sandström, Niklas; Frisk, Thomas; Stemme, Göran; van der Wijngaart, Wouter

    2008-01-01

    We introduce a novel approach for greatly improved transport and trapping of airborne sample to a microfluidic analysis system by integrating an electrohydrodynamic (EHD) air pump with a microfluidic air-liquid interface. In our system, a negative corona discharge partially ionizes the air around a sharp electrode tip while the electrostatic field accelerates airborne particles towards an electrically grounded liquid surface, where they absorb. The air-liquid interface is fixated at the micro...

  12. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit

    OpenAIRE

    Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J; Banfield, Jillian F; Nazaroff, William W.

    2016-01-01

    Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupanc...

  13. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit.

    OpenAIRE

    Licina, D; Bhangar, S; Brooks, B.; Baker, R; Firek, B; Tang, X; Morowitz, MJ; Banfield, JF; Nazaroff, WW

    2016-01-01

    Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupanc...

  14. Ventilation conditions and air-borne bacteria and particles in operating theatres: proposed safe economies.

    OpenAIRE

    Clark, R. P.; Reed, P. J.; Seal, D V; Stephenson, M. L.

    1985-01-01

    Concentrations of air-borne bacteria and particles have been measured in turbulently ventilated operating theatres in full flow, half flow and zero flow conditions. Increased air-borne challenge produced by human activity and by mechanical cleaning procedures is demonstrated: die-away of this contamination is shown to be related to the ventilation rate. Ventilation can be reduced or turned off at night and during weekends, and cleaning can also be carried out, without increased risk of infect...

  15. Assessment of oxidative DNA damage formation by organic complex mixtures from airborne particles PM10

    International Nuclear Information System (INIS)

    The free radical generating activity of airborne particulate matter (PM10) has been proposed as a primary mechanism in biological activity of ambient air pollution. In an effort to determine the impact of the complex mixtures of extractable organic matter (EOM) from airborne particles on oxidative damage to DNA, the level of 8-oxo-2'-deoxyguanosine (8-oxodG), the most prevalent and stable oxidative lesion, was measured in the human metabolically competent cell line Hep G2. Cultured cells were exposed to equivalent EOM concentrations (5-150 μg/ml) and oxidative DNA damage was analyzed using a modified single cell gel electrophoresis (SCGE), which involves the incubation of whole cell DNA with repair specific DNA endonuclease, which cleaves oxidized DNA at the sites of 8-oxodG. EOMs were extracted from PM10 collected daily (24 h intervals) in three European cities: Prague (Czech Republic, two monitoring sites, Libus and Smichov), Kosice (Slovak Republic) and Sofia (Bulgaria) during 3-month sampling periods in the winter and summer seasons. No substantial time- and dose-dependent increase of oxidative DNA lesions was detected in EOM-treated cells with the exception of the EOM collected at the monitoring site Kosice, summer sampling. In this case, 2 h cell exposure to EOM resulted in a slight but significant increase of oxidative DNA damage at three from total of six concentrations. The mean 8-oxodG values at these concentrations ranged from 15.3 to 26.1 per 106 nucleotides with a value 3.5 per 106 nucleotides in untreated cells. B[a]P, the positive control, induced a variable but insignificant increase of oxidative DNA damage in Hep G2 cell (approximately 1.6-fold increase over control value). Based on these data we believe that EOM samples extracted from airborne particle PM10 play probably only a marginal role in oxidative stress generation and oxidative lesion formation to DNA. However, adsorbed organic compounds can undergo various interactions (additive or

  16. Assessment of oxidative DNA damage formation by organic complex mixtures from airborne particles PM(10).

    Science.gov (United States)

    Gábelová, Alena; Valovicová, Zuzana; Lábaj, Juraj; Bacová, Gabriela; Binková, Blanka; Farmer, Peter B

    2007-07-01

    The free radical generating activity of airborne particulate matter (PM(10)) has been proposed as a primary mechanism in biological activity of ambient air pollution. In an effort to determine the impact of the complex mixtures of extractable organic matter (EOM) from airborne particles on oxidative damage to DNA, the level of 8-oxo-2'-deoxyguanosine (8-oxodG), the most prevalent and stable oxidative lesion, was measured in the human metabolically competent cell line Hep G2. Cultured cells were exposed to equivalent EOM concentrations (5-150microg/ml) and oxidative DNA damage was analyzed using a modified single cell gel electrophoresis (SCGE), which involves the incubation of whole cell DNA with repair specific DNA endonuclease, which cleaves oxidized DNA at the sites of 8-oxodG. EOMs were extracted from PM(10) collected daily (24h intervals) in three European cities: Prague (Czech Republic, two monitoring sites, Libus and Smíchov), Kosice (Slovak Republic) and Sofia (Bulgaria) during 3-month sampling periods in the winter and summer seasons. No substantial time- and dose-dependent increase of oxidative DNA lesions was detected in EOM-treated cells with the exception of the EOM collected at the monitoring site Kosice, summer sampling. In this case, 2h cell exposure to EOM resulted in a slight but significant increase of oxidative DNA damage at three from total of six concentrations. The mean 8-oxodG values at these concentrations ranged from 15.3 to 26.1 per 10(6) nucleotides with a value 3.5 per 10(6) nucleotides in untreated cells. B[a]P, the positive control, induced a variable but insignificant increase of oxidative DNA damage in Hep G2 cell (approximately 1.6-fold increase over control value). Based on these data we believe that EOM samples extracted from airborne particle PM(10) play probably only a marginal role in oxidative stress generation and oxidative lesion formation to DNA. However, adsorbed organic compounds can undergo various interactions

  17. On the interaction between glyceraldehyde-3-phosphate dehydrogenase and airborne particles: Evidence for electrophilic species

    Science.gov (United States)

    Shinyashiki, Masaru; Rodriguez, Chester E.; Di Stefano, Emma W.; Sioutas, Constantinos; Delfino, Ralph J.; Kumagai, Yoshito; Froines, John R.; Cho, Arthur K.

    Many of the adverse health effects of airborne particulate matter (PM) have been attributed to the chemical properties of some of the large number of chemical species present in PM. Some PM component chemicals are capable of generating reactive oxygen species and eliciting a state of oxidative stress. In addition, however, PM can contain chemical species that elicit their effects through covalent bond formation with nucleophilic functions in the cell. In this manuscript, we report the presence of constituents with electrophilic properties in ambient and diesel exhaust particles, demonstrated by their ability to inhibit the thiol enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). GAPDH is irreversibly inactivated by electrophiles under anaerobic conditions by covalent bond formation. This inactivation can be blocked by the prior addition of a high concentration of dithiothreitol (DTT) as an alternate nucleophile. Addition of DTT after the reaction between the electrophile and GAPDH, however, does not reverse the inactivation. This property has been utilized to develop a procedure that provides a quantitative measure of electrophiles present in samples of ambient particles collected in the Los Angeles Basin and in diesel exhaust particles. The toxicity of electrophiles is the result of irreversible changes in biological molecules; recovery is dependent on resynthesis. If the resynthesis is slow, the irreversible effects can be cumulative and manifest themselves after chronic exposure to low levels of electrophiles.

  18. Airborne particle monitoring with urban closed-circuit television camera networks and a chromatic technique

    International Nuclear Information System (INIS)

    An economic approach for the preliminary assessment of 2–10 µm sized (PM10) airborne particle levels in urban areas is described. It uses existing urban closed-circuit television (CCTV) surveillance camera networks in combination with particle accumulating units and chromatic quantification of polychromatic light scattered by the captured particles. Methods for accommodating extraneous light effects are discussed and test results obtained from real urban sites are presented to illustrate the potential of the approach

  19. The next generation airborne polarimetric Doppler weather radar

    OpenAIRE

    Vivekanandan, J.; W.-C. Lee; E. Loew; Salazar, J. L.; Grubišić, V.; J. Moore; Tsai, P

    2014-01-01

    Results from airborne field deployments emphasized the need to obtain concurrently high temporal and spatial resolution measurements of 3-D winds and microphysics. A phased array radar on an airborne platform using dual-polarization antenna has the potential for retrieving high resolution, collocated 3-D winds and microphysical measurements. Recently, ground-based phased array radar (PAR) demonstrated the high time resolution estimation of accurate Doppler velocity and reflecti...

  20. The next generation airborne polarimetric Doppler weather radar

    OpenAIRE

    Vivekanandan, J.; W.-C. Lee; E. Loew; Salazar, J. L.; Grubišić, V.; J. Moore; Tsai, P

    2014-01-01

    Results from airborne field deployments emphasized the need to obtain concurrently high temporal and spatial resolution measurements of 3-D winds and microphysics. A phased array radar on an airborne platform using dual-polarization antenna has the potential for retrieving high-resolution, collocated 3-D winds and microphysical measurements. Recently, ground-based phased array radar (PAR) has demonstrated the high time-resolution estimation of accurate Doppler velocity and...

  1. Size distribution of airborne mist and endotoxin-containing particles in metalworking fluid environments.

    Science.gov (United States)

    Wang, Hongxia; Reponen, Tiina; Lee, Shu-An; White, Eugene; Grinshpun, Sergey A

    2007-03-01

    The objective of the study was to investigate size-selective concentrations of airborne particles and endotoxin in metalworking fluid (MWF) environments. The experiments were conducted under two conditions: (1) MWF collected in the field was aerosolized with a laboratory-scale simulator (MWF simulator) in the laboratory; and (2) MWFs were aerosolized during routine field operations. All experiments included size-selective measurement of airborne concentrations of particle numbers and endotoxin mass using an electrical low-pressure impactor. During field sampling, the total microbial and endotoxin concentrations in the air were also measured with a BioSampler, and the mass concentration of MWF mists was measured with a photometer. Airborne particle concentrations were highest in the fine particle size ranges in the areas affected by MWFs. Relatively high concentrations of endotoxin were detected at particle size below 0.39 mum, which is smaller than the size of intact bacterial cells. The total microbial and endotoxin analysis revealed high microbial contamination in one sampling site although the total particle mass was not elevated. It was concluded that MWF sites can be contaminated with high concentrations of fine particles, and these fine particles may contain microbial components, such as endotoxin. The results call for the size-selective measurement of particles and endotoxin for more comprehensive exposure assessment in MWF facilities. PMID:17237021

  2. 3D model generation using an airborne swarm

    Science.gov (United States)

    Clark, R. A.; Punzo, G.; Dobie, G.; MacLeod, C. N.; Summan, R.; Pierce, G.; Macdonald, M.; Bolton, G.

    2015-03-01

    Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm's computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced.

  3. 3D model generation using an airborne swarm

    International Nuclear Information System (INIS)

    Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm’s computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced

  4. 3D model generation using an airborne swarm

    Energy Technology Data Exchange (ETDEWEB)

    Clark, R. A.; Punzo, G.; Macdonald, M. [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom); Dobie, G.; MacLeod, C. N.; Summan, R.; Pierce, G. [Centre for Ultrasonic Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom); Bolton, G. [National Nuclear Laboratory Limited, Chadwick House, Warrington Road, Birchwood Park, Warrington, WA3 6AE (United Kingdom)

    2015-03-31

    Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm’s computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced.

  5. MEMS-based silicon cantilevers with integrated electrothermal heaters for airborne ultrafine particle sensing

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

    2013-05-01

    The development of low-cost and low-power MEMS-based cantilever sensors for possible application in hand-held airborne ultrafine particle monitors is described in this work. The proposed resonant sensors are realized by silicon bulk micromachining technology with electrothermal excitation, piezoresistive frequency readout, and electrostatic particle collection elements integrated and constructed in the same sensor fabrication process step of boron diffusion. Built-in heating resistor and full Wheatstone bridge are set close to the cantilever clamp end for effective excitation and sensing, respectively, of beam deflection. Meanwhile, the particle collection electrode is located at the cantilever free end. A 300 μm-thick, phosphorus-doped silicon bulk wafer is used instead of silicon-on-insulator (SOI) as the starting material for the sensors to reduce the fabrication costs. To etch and release the cantilevers from the substrate, inductively coupled plasma (ICP) cryogenic dry etching is utilized. By controlling the etching parameters (e.g., temperature, oxygen content, and duration), cantilever structures with thicknesses down to 10 - 20 μm are yielded. In the sensor characterization, the heating resistor is heated and generating thermal waves which induce thermal expansion and further cause mechanical bending strain in the out-of-plane direction. A resonant frequency of 114.08 +/- 0.04 kHz and a quality factor of 1302 +/- 267 are measured in air for a fabricated rectangular cantilever (500x100x13.5 μm3). Owing to its low power consumption of a few milliwatts, this electrothermal cantilever is suitable for replacing the current external piezoelectric stack actuator in the next generation of the miniaturized cantilever-based nanoparticle detector (CANTOR).

  6. On Airborne Wear Particles Emissions ofCommercial Disc Brake Materials– A Pin on Disc Simulation

    OpenAIRE

    Söderberg, Anders; Wahlström, Jens; Olander, Lars; Jansson, Anders; Olofsson, Ulf

    2008-01-01

    A novel test method was used to study the concentration and size distribution of airborne wear particles from disc brake materials. A pin-on-disc tribometer equipped with particle counting instruments was used as test equipment. Four different nonasbestoses-organic (NAO) linings for the U.S. market and four different low metallic linings for the EU market were tested against material from gray cast iron rotors. The result indicates that the low metallic linings are more aggressive to the roto...

  7. Characterization of winter airborne particles at Emperor Qin's Terra-cotta Museum, China

    International Nuclear Information System (INIS)

    Daytime and nighttime total suspended particulate matters (TSP) were collected inside and outside Emperor Qin's Terra-cotta Museum, the most popular on-site museum in China, in winter 2008. The purpose of this study was to investigate the contribution of visitors to indoor airborne particles in two display halls with different architectural and ventilating conditions, including Exhibition Hall and Pit No.1. Morphological and elemental analyses of 7-day individual particle samples were performed with scanning electron microscopy and energy dispersive X-ray spectrometer (SEM-EDX). Particle mass concentrations in Exhibition Hall and Pit No.1 were in a range of 54.7-291.7 μg m-3 and 95.3-285.4 μg m-3 with maximum diameters of 17.5 μm and 26.0 μm, respectively. In most sampling days, daytime/nighttime particle mass ratios in Exhibition Hall (1.30-3.12) were higher than those in Pit No.1 (0.96-2.59), indicating more contribution of the tourist flow in Exhibition Hall than in Pit No. 1. The maximum of particle size distributions were in a range of 0.5-1.0 μm, with the highest abundance (43.4%) occurred in Exhibition Hall at night. The majority of airborne particles at the Museum was composed of soil dust, S-containing particles, and low-Z particles like soot aggregate and biogenic particles. Both size distributions and particle types were found to be associated with visitor numbers in Exhibition Hall and with natural ventilation in Pit No.1. No significant influence of visitors on indoor temperature and relative humidity (RH) was found in either display halls. Those baseline data on the nature of the airborne particles inside the Museum can be incorporated into the maintenance criteria, display management, and ventilation strategy by conservators of the museum.

  8. Contribution of indoor-generated particles to residential exposure

    Science.gov (United States)

    Isaxon, C.; Gudmundsson, A.; Nordin, E. Z.; Lönnblad, L.; Dahl, A.; Wieslander, G.; Bohgard, M.; Wierzbicka, A.

    2015-04-01

    The majority of airborne particles in residences, when expressed as number concentrations, are generated by the residents themselves, through combustion/thermal related activities. These particles have a considerably smaller diameter than 2.5 μm and, due to the combination of their small size, chemical composition (e.g. soot) and intermittently very high concentrations, should be regarded as having potential to cause adverse health effects. In this study, time resolved airborne particle measurements were conducted for seven consecutive days in 22 randomly selected homes in the urban area of Lund in southern Sweden. The main purpose of the study was to analyze the influence of human activities on the concentration of particles in indoor air. Focus was on number concentrations of particles with diameters Correlations between these particles and soot mass concentration in total dust were also investigated. It was found that candle burning and activities related to cooking (using a frying pan, oven, toaster, and their combinations) were the major particle sources. The frequency of occurrence of a given concentration indoors and outdoors was compared for ultrafine particles. Indoor data was sorted into non-occupancy and occupancy time, and the occupancy time was further divided into non-activity and activity influenced time. It was found that high levels (above 104 cm-3) indoors mainly occur during active periods of occupancy, while the concentration during non-activity influenced time differs very little from non-occupancy time. Total integrated daily residential exposure of ultrafine particles was calculated for 22 homes, the contribution from known activities was 66%, from unknown activities 20%, and from background/non-activity 14%. The collected data also allowed for estimates of particle source strengths for specific activities, and for some activities it was possible to estimate correlations between the number concentration of ultrafine particles and the mass

  9. Direct Characterization of Airborne Particles Associated with Arsenic-rich Mine Tailings: Particle Size Mineralogy and Texture

    Energy Technology Data Exchange (ETDEWEB)

    M Corriveau; H Jamieson; M Parsons; J Campbell; A Lanzirotti

    2011-12-31

    Windblown and vehicle-raised dust from unvegetated mine tailings can be a human health risk. Airborne particles from As-rich abandoned Au mine tailings from Nova Scotia, Canada have been characterized in terms of particle size, As concentration, As oxidation state, mineral species and texture. Samples were collected in seven aerodynamically fractionated size ranges (0.5-16 {micro}m) using a cascade impactor deployed at three tailings fields. All three sites are used for recreational activities and off-road vehicles were racing on the tailings at two mines during sample collection. Total concentrations of As in the <8 {micro}m fraction varied from 65 to 1040 ng/m{sup 3} of air as measured by proton-induced X-ray emission (PIXE) analysis. The same samples were analysed by synchrotron-based microfocused X-ray absorption near-edge spectroscopy ({micro}XANES) and X-ray diffraction ({micro}XRD) and found to contain multiple As-bearing mineral species, including Fe-As weathering products. The As species present in the dust were similar to those observed in the near-surface tailings. The action of vehicles on the tailings surface may disaggregate material cemented with Fe arsenate and contribute additional fine-grained As-rich particles to airborne dust. Results from this study can be used to help assess the potential human health risks associated with exposure to airborne particles from mine tailings.

  10. Airborne endotoxin associated with particles of different sizes and affected by water content in handled straw.

    Science.gov (United States)

    Madsen, A M; Nielsen, S H

    2010-07-01

    High exposures to endotoxin are observed in environments where organic materials are handled and lower exposures are found in e.g. indoor air. Inhaled endotoxin contributes significantly to the induction of airway inflammation and dysfunction. The size of an inhaled particle influences the deposition in the airways and the following health symptoms. The objective is to characterise the distribution of endotoxin on airborne particles of different sizes in straw storage halls with high exposure and in other environments with lower exposure levels to endotoxin. Furthermore we have studied the influence of water content of handled straw on the size distribution of endotoxin containing particles. Total, inhalable, thoracic and respirable endotoxin and particles have each been quantified in aerosols from boiler rooms and straw storage halls at 24 power plants, including 21 biofuel plants. Inhalable, thoracic and respirable endotoxin have been quantified in aerosols from offices and outdoor air. The endotoxin concentration was higher in airborne thoracic dust than in airborne 'total dust'. The median respirable fraction in the straw storage halls, boiler rooms at biofuel plants, boiler rooms at conventional plants, offices and outdoors was respectively 42%, 9%, 19%, 24% and 34%. Thoracic endotoxin per number of thoracic particles was higher than respirable endotoxin per number of respirable particles at the biofuel plants. In straw storage halls the fraction of endotoxin of respirable size was highest on the days with lowest water content in the received straw. Furthermore the exposures to all endotoxin fractions were highest on days with the lowest water content in the received straw. In conclusion the highest exposures and concentrations of endotoxin occur or tend to occur from thoracic dust. A high variation in endotoxin concentrations and in fractions of respirable or thoracic size is found in the different working areas. This is important in the risk assessment and

  11. Particle size analysis in estimating the significance of airborne contamination

    International Nuclear Information System (INIS)

    In this report information on pertinent methods and techniques for analysing particle size distributions is compiled. The principles underlying the measurement methods are described, and the merits of different methods in relation to the information being sought and to their usefulness in the laboratory and in the field are explained. Descriptions on sampling methods, gravitational and inertial particle separation methods, electrostatic sizing devices, diffusion batteries, optical sizing techniques and autoradiography are included. Finally, the report considers sampling for respirable activity and problems related to instrument calibration

  12. Retention of airborne particles in granular bed filters

    International Nuclear Information System (INIS)

    A literature survey was made on theoretical models for the prediction of particle retention in sand beds. Also data on observed retention was collected from the literature. Based on this information, a semi-empirical model was compiled. Comparison of the model with published retention data shows a general agreement. (Auth.)

  13. Evaluation of cell sorting aerosols and containment by an optical airborne particle counter.

    Science.gov (United States)

    Xie, Mike; Waring, Michael T

    2015-08-01

    Understanding aerosols produced by cell sorting is critical to biosafety risk assessment and validation of containment efficiency. In this study an Optical Airborne Particle Counter was used to analyze aerosols produced by the BD FACSAria and to assess the effectiveness of its aerosol containment. The suitability of using this device to validate containment was directly compared to the Glo-Germ method put forth by the International Society for Advancement of Cytometry (ISAC) as a standard for testing. It was found that high concentrations of aerosols ranging from 0.3 µm to 10 µm can be detected in failure mode, with most less than 5 µm. In most cases, while numerous aerosols smaller than 5 µm were detected by the Optical Airborne Particle Counter, no Glo-Germ particles were detected, indicating that small aerosols are under-evaluated by the Glo-Germ method. The results demonstrate that the Optical Airborne Particle Counter offers a rapid, economic, and quantitative analysis of cell sorter aerosols and represents an improved method over Glo-Germ for the task of routine validation and monitoring of aerosol containment for cell sorting. PMID:26012776

  14. Direct characterization of airborne particles associated with arsenic-rich mine tailings: Particle size, mineralogy and texture

    Energy Technology Data Exchange (ETDEWEB)

    Corriveau, M.C. [Department of Geological Sciences and Geological Engineering, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Jamieson, H.E., E-mail: jamieson@geol.queensu.ca [Department of Geological Sciences and Geological Engineering, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Parsons, M.B. [Geological Survey of Canada (Atlantic), Natural Resources Canada, Dartmouth, Nova Scotia, B2Y 4A2 (Canada); Campbell, J.L. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Lanzirotti, A. [Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637 (United States)

    2011-09-15

    Highlights: > Airborne dust from As-rich gold mine tailings used for recreation was collected. > Total concentrations of arsenic in the <8 {mu}m fraction varied from 65 to 1040 ng/m{sup 3}. > Multiple As minerals in dust are comparable with near-surface tailings samples. - Abstract: Windblown and vehicle-raised dust from unvegetated mine tailings can be a human health risk. Airborne particles from As-rich abandoned Au mine tailings from Nova Scotia, Canada have been characterized in terms of particle size, As concentration, As oxidation state, mineral species and texture. Samples were collected in seven aerodynamically fractionated size ranges (0.5-16 {mu}m) using a cascade impactor deployed at three tailings fields. All three sites are used for recreational activities and off-road vehicles were racing on the tailings at two mines during sample collection. Total concentrations of As in the <8 {mu}m fraction varied from 65 to 1040 ng/m{sup 3} of air as measured by proton-induced X-ray emission (PIXE) analysis. The same samples were analysed by synchrotron-based microfocused X-ray absorption near-edge spectroscopy ({mu}XANES) and X-ray diffraction ({mu}XRD) and found to contain multiple As-bearing mineral species, including Fe-As weathering products. The As species present in the dust were similar to those observed in the near-surface tailings. The action of vehicles on the tailings surface may disaggregate material cemented with Fe arsenate and contribute additional fine-grained As-rich particles to airborne dust. Results from this study can be used to help assess the potential human health risks associated with exposure to airborne particles from mine tailings.

  15. Allergens in Paved Road Dust and Airborne Particles

    OpenAIRE

    Miguel, Ann G.; Cass, Glen R.; Glovsky, M. Michael; Weiss, Jay

    1999-01-01

    Paved road dust present on the surface of streets in Southern California consists of a complex mixture of soil dust, deposited motor vehicle exhaust particles, tire dust, brake lining wear dust, plant fragments, and other biological materials. The research presented here shows that allergens from at least 20 different source materials are found in the paved road dust. These include pollens and pollen fragments, animal dander, and molds. When paved road dust is resuspended into the atmosphere ...

  16. Characterization of individual airborne particles in Taiyuan City, China

    OpenAIRE

    Xie, R. K.; Seip, H. M.; L. Liu; Zhang, D.S.

    2009-01-01

    Taiyuan, the capital of Shanxi province, China, is one of the most polluted cities in the world. To characterize the ambient particulate pollution, samples of particulates with aerodynamic diameter less than 10 µm (PM10) were collected during a 6-day campaign. Individual particles were analyzed by Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS) to determine their chemical composition. Meanwhile, photomicrographs were obtained from SEM to aid in particles’ source ide...

  17. Identification and characterization of individual airborne volcanic ash particles by Raman microspectroscopy.

    Science.gov (United States)

    Ivleva, Natalia P; Huckele, Susanne; Weinzierl, Bernadett; Niessner, Reinhard; Haisch, Christoph; Baumann, Thomas

    2013-11-01

    We present for the first time the Raman microspectroscopic identification and characterization of individual airborne volcanic ash (VA) particles. The particles were collected in April/May 2010 during research aircraft flights, which were performed by Deutsches Zentrum für Luft- und Raumfahrt in the airspace near the Eyjafjallajökull volcano eruption and over Europe (between Iceland and Southern Germany). In addition, aerosol particles were sampled by an Electrical Low Pressure Impactor in Munich, Germany. As references for the Raman analysis, we used the spectra of VA collected at the ground near the place of eruption, of mineral basaltic rock, and of different minerals from a database. We found significant differences in the spectra of VA and other aerosol particles (e.g., soot, nitrates, sulfates, and clay minerals), which allowed us to identify VA among other atmospheric particulate matter. Furthermore, while the airborne VA shows a characteristic Raman pattern (with broad band from ca. 200 to ca. 700 cm(-1) typical for SiO₂ glasses and additional bands of ferric minerals), the differences between the spectra of aged and fresh particles were observed, suggesting differences in their chemical composition and/or structure. We also analyzed similarities between Eyjafjallajökull VA particles collected at different sampling sites and compared the particles with a large variety of glassy and crystalline minerals. This was done by applying cluster analysis, in order to get information on the composition and structure of volcanic ash. PMID:24121468

  18. Sampling and Characterization of Airborne Particle from Car Brakes Testing

    Czech Academy of Sciences Publication Activity Database

    Moravec, Pavel; Smolík, Jiří; Schwarz, Jaroslav; Ševčíková, Irena; Kukutschová, J.; Tomášek, V.

    Praha: Česká aerosolová společnost, 2009, s. 25-30. ISBN 978-80-86186-20-7. [Konference České aerosolové společnosti /10./. Čejkovice (CZ), 12.11.2009-13.11.2009] R&D Projects: GA ČR GA106/07/1436 Institutional research plan: CEZ:AV0Z40720504 Keywords : friction * size resolved sampling * wear particles Subject RIV: CF - Physical ; Theoretical Chemistry http://cas.icpf.cas.cz/download/Sbornik_VKCAS_2009.pdf

  19. Indoor and outdoor airborne particles. An in vitro study on mutagenic potential and toxicological implications.

    OpenAIRE

    Houdt, van, R.

    1988-01-01

    IntroductionAir pollution components are present as gases and as particulate matter. As particle deposition takes place in various parts of the respiratory system particulate matter may have other toxicological implications than gaseous pollutants, which all may penetrate in the lower part of the respiratory tract. In addition, suspended particulate matter represents a group of pollutants of variable physical as well as chemical composition. Therefore airborne particulate matter cannot be reg...

  20. Assessment of oxidative DNA damage formation by organic complex mixtures from airborne particles PM10

    Czech Academy of Sciences Publication Activity Database

    Gábelová, A.; Valovičová, Z.; Lábaj, J.; Bačová, G.; Binková, Blanka; Farmer, P. B.

    2007-01-01

    Roč. 620, 1-2 (2007), s. 135-144. ISSN 0027-5107 Grant ostatní: EU(EU) 2000-00091 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK Keywords : airborne particles PM10 * oxidative DNA damage * 8-oxoguanine Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  1. Airborne Release of Particles in Overheating Incidents Involving Plutonium Metal and Compounds

    International Nuclear Information System (INIS)

    Ever-increasing utilization of nuclear fuels will result in wide-scale plutonium recovery processing, reconstitution of fuels, transportation, and extensive handling of this material. A variety of circumstances resulting in overheating and fires involving plutonium may occur, releasing airborne particles. This work describes the observations from a study in which the airborne release of plutonium and its compounds was measured during an exposure of the material of interest containing plutonium to temperatures which may result from fires. Aerosol released from small cylinders of metallic plutonium ignited in air at temperatures from 410 to 650°C ranged from 3 x 10-6 to 5 x 10-5 wt%. Particles smaller than 15μm in diameter represented as much as 0.03% of the total released. Large plutonium pieces weighing from 456 to 1770 g were ignited and allowed to oxidize completely in air with a velocity of around 500 cm/sec. Release rates of from 0.0045 to 0.032 wt% per hour were found. The median mass diameter of airborne material was 4 μm. Quenching the oxidation with magnesium oxide sand reduced the release to 2.9 X 10-4 wt% per hour. Many experiments were carried out in which plutonium compounds as powders were heated at temperatures ranging from 700 to 1000°C with several air flows. Release rates ranged from 5 x 10-8 to 0.9 wt% per hour, depending upon the compound and the conditions imposed. The airborne release from boiling solutions of plutonium nitrate were roughly related to energy of boiling, and ranged from 4 x 10-4 to 2 x 10-1 % for the evaporation of 90% of the solution. The fraction airborne when combustibles contaminated with plutonium are burned is under study. The data reported can be used in assessing the consequences of off-standard situations involving plutonium and its compounds in fires. (author)

  2. Predicting emissions of SVOCs from polymeric materials and their interaction with airborne particles.

    Science.gov (United States)

    Xu, Ying; Little, John C

    2006-01-15

    A model that predicts the emission rate of volatile organic compounds (VOCs) from building materials is extended and used to predict the emission rate of semivolatile organic compounds (SVOCs) from polymeric materials. Reasonable agreement between model predictions and gas-phase di-2-ethylhexyl phthalate (DEHP) concentrations is achieved using data collected in a previous experimental study that measured emissions of DEHP from vinyl flooring in two very different chambers. While emissions of highly volatile VOCs are subject to "internal" control (the material-phase diffusion coefficient), emissions of the very low volatility SVOCs are subject to "external" control (partitioning into the gas phase, the convective mass-transfer coefficient, and adsorption onto interior surfaces). The effect of SVOCs partitioning onto airborne particles is also examined. The DEHP emission rate is increased when the gas-phase concentration is high, and especially when partitioning to the airborne particles is strong. Airborne particles may play an important role in inhalation exposure as well as in transporting SVOCs well beyond the source. Although more rigorous validation is needed, the model should help elucidate the mechanisms governing emissions of phthalate plasticizers, brominated flame retardants, biocides, and other SVOCs from a wide range of building materials and consumer products. PMID:16468389

  3. Total airborne mold particle sampling: evaluation of sample collection, preparation and counting procedures, and collection devices.

    Science.gov (United States)

    Godish, Diana; Godish, Thad

    2008-02-01

    This study was conducted to evaluate (i) procedures used to collect, prepare, and count total airborne mold spore/particle concentrations, and (ii) the relative field performance of three commercially available total airborne mold spore/particle sampling devices. Differences between factory and laboratory airflow calibration values of axial fan-driven sampling instruments (used in the study) indicated a need for laboratory calibration using a mass flow meter to ensure that sample results were accurately calculated. An aniline blue-amended Calberla's solution adjusted to a pH of 4.2-4.4 provided good sample mounting/counting results using Dow Corning high vacuum grease, Dow Corning 280A adhesive, and Dow Corning 316 silicone release spray for samples collected using mini-Burkard and Allergenco samplers. Count variability among analysts was most pronounced in 5% counts of relatively low mold particle deposition density samples and trended downward with increased count percentage and particle deposition density. No significant differences were observed among means of 5, 10, and 20% counts and among analysts; a significant interaction effect was observed between analysts' counts and particle deposition densities. Significantly higher mini-Burkard and Air-O-Cell total mold spore/particle counts for 600x vs. 400x (1.9 and 2.3 x higher, respectively), 1000x vs. 600x (1.9 and 2.2 x higher, respectively) and 1000x vs. 400x (3.6 and 4.6 x higher, respectively) comparisons indicated that 1000x magnification counts best quantified total airborne mold spore/particles using light microscopy, and that lower magnification counts may result in unacceptable underreporting of airborne mold spore/particle concentrations. Modest but significantly higher (1.2x) total mold spore concentrations were observed with Allergenco vs. mini-Burkard samples collected in co-located, concurrently operated sampler studies; moderate but significantly higher mini-Burkard count values (1.4x) were

  4. Approximation for the absorption coefficient of airborne atmospheric aerosol particles in terms of measurable bulk properties

    OpenAIRE

    HÄNEL, GOTTFRIED; Dlugi, Ralph

    2011-01-01

    The absorption coefficient of airborne atmospheric aerosol particles can be approximated by where λ is the wavelength of radiation, n — ik is the mean complex refractive index, ρ the mean bulk density, and M/Vk the mass of the particles per unit volume of air. This approximation gives good results at relative humidities between 0 and 0.95 for the wavelengths of radiation between 0.55 μm and 2.0 μm and between 9.25 μm and 12.0 μm. Basing on this approximation it is possible to determine the s...

  5. A review of airborne particle sampling with special reference to long-lived radioactive dust

    International Nuclear Information System (INIS)

    This report reviews some basic aspects related to the sampling of airborne particles with special reference to Long-Lived Radioactive Dust (LLRD). The report covers a number of areas of practical interest such as the production of aerosols, the dynamics of suspended particles, the physical and chemical characteristics and properties of dust clouds, and the inhalation and measurement of dust. It is followed with a brief review of dust sampling instrumentation, and with a short account of the work done on LLRD in Canada with a few references to work done outside this country. (34 figs., 7 tabs., 117 refs.)

  6. Combustion generated fine carbonaceous particles

    OpenAIRE

    Bockhorn, Henning; D'Anna, Andrea; Sarofim, Adel F.; Wang, Hai

    2009-01-01

    Soot is of importance for its contribution to atmospheric particles with their adverse health impacts and for its contributions to heat transfer in furnaces and combustors, to luminosity from candles, and to smoke that hinders escape from buildings during fires and that impacts global warming or cooling. The different chapters of the book adress comprehensively the different aspects from fundamental approaches to applications in technical combustion devices.

  7. Use of GSR particle analysis program on an analytical SEM to identify sources of emission of airborne particles

    International Nuclear Information System (INIS)

    Full text: High concentrations of airborne particles, in particular PM10 (particulate matter 10, but has been little used in Australia for airborne particulates. Two sets of 15 mm PM10 samples were collected in March and April 2000 from two sites in Brisbane, one within a suburb and one next to an arterial road. The particles were collected directly onto double-sided carbon tapes with a cascade impactor attached to a high-volume PM10 sampler. The carbon tapes were analysed in a JEOL 840 SEM equipped with a Be-window energy-dispersive X-ray detector and Moran Scientific microanalysis system. An automated Gun Shot Residue (GSR) program was used together with backscattered electron imaging to characterise and analyse individual particulates. About 6,000 particles in total were analysed for each set of impactor samples. Due to limitations of useful pixel size, only particles larger than about 0.5 μm could be analysed. The size, shape and estimated elemental composition (from Na to Pb) of the particles were subjected to non-hierarchical cluster analysis and the characteristics of the clusters were related to their possible sources of emission. Both samples resulted in similar particle clusters. The particles could be classified into three main categories non-spherical (58% of the total number of analysed particles, shape factor >1 1), spherical (15%) and 'carbonaceous' (27%, ie with unexplained % of elemental mass >75%). Non-spherical particles were mainly sea salt and soil particles, and a small amount of iron, lead and mineral dust. The spherical particles were mainly sea salt particles and flyash, and a small amount of iron, lead and secondary sulphate dust. The carbonaceous particles included carbon material mixed with secondary aerosols, roadside dust, sea salt or industrial dust. The arterial road sample also contained more roadside dust and less secondary aerosols than the suburb sample. Current limitations with this method are the minimum particle size

  8. Cloud particle size distributions measured with an airborne digital in-line holographic instrument

    Directory of Open Access Journals (Sweden)

    J. P. Fugal

    2009-03-01

    Full Text Available Holographic data from the prototype airborne digital holographic instrument HOLODEC (Holographic Detector for Clouds, taken during test flights are digitally reconstructed to obtain the size (equivalent diameters in the range 23 to 1000 μm, three-dimensional position, and two-dimensional profile of ice particles and then ice particle size distributions and number densities are calculated using an automated algorithm with minimal user intervention. The holographic method offers the advantages of a well-defined sample volume size that is not dependent on particle size or airspeed, and offers a unique method of detecting shattered particles. The holographic method also allows the volume sample rate to be increased beyond that of the prototype HOLODEC instrument, limited solely by camera technology.

    HOLODEC size distributions taken in mixed-phase regions of cloud compare well to size distributions from a PMS FSSP probe also onboard the aircraft during the test flights. A conservative algorithm for detecting shattered particles utilizing the particles depth-position along the optical axis eliminates the obvious ice particle shattering events from the data set. In this particular case, the size distributions of non-shattered particles are reduced by approximately a factor of two for particles 15 to 70 μm in equivalent diameter, compared to size distributions of all particles.

  9. Airborne lidar measurements of smoke plume distribution, vertical transmission, and particle size

    International Nuclear Information System (INIS)

    Observations were made of a dense smoke plume downwind from a forest using the ALPHA-1 two-wavelength downward-looking airborne lidar system. Facsimile displays derived from lidar signatures depict plume dimensions, boundary layer height, and underlying terrain elevation. Surface returns are interpreted in terms of vertical transmissions as function of cross-plume distance. Results show significantly greater plume attenuation at 0.53-μm wavelength than at 1.06-μm, indicating approx.0.1-μm mean particle diameters of the presence of gaseous constituents that absorb the visible radiation. These results demonstrate the potential of multiple-wavelength airborne lidar for quantitative analysis of atmospheric particulate and gaseous constituents

  10. A review of methods for sampling large airborne particles and associated radioactivity

    International Nuclear Information System (INIS)

    Radioactive particles, tens of μm or more in diameter, are unlikely to be emitted directly from nuclear facilities with exhaust gas cleansing systems, but may arise in the case of an accident or where resuspension from contaminated surfaces is significant. Such particles may dominate deposition and, according to some workers, may contribute to inhalation doses. Quantitative sampling of large airborne particles is difficult because of their inertia and large sedimentation velocities. The literature describes conditions for unbiased sampling and the magnitude of sampling errors for idealised sampling inlets in steady winds. However, few air samplers for outdoor use have been assessed for adequacy of sampling. Many size selective sampling methods are found in the literature but few are suitable at the low concentrations that are often encountered in the environment. A number of approaches for unbiased sampling of large particles have been found in the literature. Some are identified as meriting further study, for application in the measurement of airborne radioactivity. (author)

  11. A Lagrangian particle model to predict the airborne spread of foot-and-mouth disease virus

    Science.gov (United States)

    Mayer, D.; Reiczigel, J.; Rubel, F.

    Airborne spread of bioaerosols in the boundary layer over a complex terrain is simulated using a Lagrangian particle model, and applied to modelling the airborne spread of foot-and-mouth disease (FMD) virus. Two case studies are made with study domains located in a hilly region in the northwest of the Styrian capital Graz, the second largest town in Austria. Mountainous terrain as well as inhomogeneous and time varying meteorological conditions prevent from application of so far used Gaussian dispersion models, while the proposed model can handle these realistically. In the model, trajectories of several thousands of particles are computed and the distribution of virus concentration near the ground is calculated. This allows to assess risk of infection areas with respect to animal species of interest, such as cattle, swine or sheep. Meteorological input data like wind field and other variables necessary to compute turbulence were taken from the new pre-operational version of the non-hydrostatic numerical weather prediction model LMK ( Lokal-Modell-Kürzestfrist) running at the German weather service DWD ( Deutscher Wetterdienst). The LMK model provides meteorological parameters with a spatial resolution of about 2.8 km. To account for the spatial resolution of 400 m used by the Lagrangian particle model, the initial wind field is interpolated upon the finer grid by a mass consistent interpolation method. Case studies depict a significant influence of local wind systems on the spread of virus. Higher virus concentrations at the upwind side of the hills and marginal concentrations in the lee are well observable, as well as canalization effects by valleys. The study demonstrates that the Lagrangian particle model is an appropriate tool for risk assessment of airborne spread of virus by taking into account the realistic orographic and meteorological conditions.

  12. The generation of particles with a vibrating reed aerosol generator

    International Nuclear Information System (INIS)

    The adhesion of contaminant particles to surfaces is a major problem in many industries. The strength of adhesion is dependent on the physical and chemical properties of the individual particles and those of the surface. The purpose of this project is to develop a sampling protocol to reproducibly remove particles from a surface thereby qualitatively measuring the adhesion strength. The suspended particles are subsequently collected and characterized by electron microscopy. The measurement of adhesion strength and subsequent characterization will enhance our understanding of adhesion of particles to surfaces. The approach towards development of a sampling protocol is to direct a stream of clean gas of known velocity on to a surface at varying angles, where particles have been previously deposited. The initial task is the development of a generator of monodisperse particles of known composition that can be deposited on a well defined surface. The authors have begun construction of a vibrating reed aerosol generator. The generator is based on the principal that a thin wire sweeps through a solution reservoir detaching droplets which on evaporation produce a stream of dry, solid particles of uniform size. The operational parameters of this aerosol generating system have been explored

  13. SKYWARD: the next generation airborne infrared search and track

    Science.gov (United States)

    Fortunato, L.; Colombi, G.; Ondini, A.; Quaranta, C.; Giunti, C.; Sozzi, B.; Balzarotti, G.

    2016-05-01

    Infrared Search and Track systems are an essential element of the modern and future combat aircrafts. Passive automatic search, detection and tracking functions, are key points for silent operations or jammed tactical scenarios. SKYWARD represents the latest evolution of IRST technology in which high quality electro-optical components, advanced algorithms, efficient hardware and software solutions are harmonically integrated to provide high-end affordable performances. Additionally, the reduction of critical opto-mechanical elements optimises weight and volume and increases the overall reliability. Multiple operative modes dedicated to different situations are available; many options can be selected among multiple or single target tracking, for surveillance or engagement, and imaging, for landing or navigation aid, assuring the maximum system flexibility. The high quality 2D-IR sensor is exploited by multiple parallel processing chains, based on linear and non-linear techniques, to extract the possible targets from background, in different conditions, with false alarm rate control. A widely tested track processor manages a large amount of candidate targets simultaneously and allows discriminating real targets from noise whilst operating with low target to background contrasts. The capability of providing reliable passive range estimation is an additional qualifying element of the system. Particular care has been dedicated to the detector non-uniformities, a possible limiting factor for distant targets detection, as well as to the design of the electro-optics for a harsh airborne environment. The system can be configured for LWIR or MWIR waveband according to the customer operational requirements. An embedded data recorder saves all the necessary images and data for mission debriefing, particularly useful during inflight system integration and tuning.

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

    Science.gov (United States)

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

    2016-06-01

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

  15. Occupational exposure to airborne particles and other pollutants in an aviation base

    International Nuclear Information System (INIS)

    The occupational exposure to airborne particles and other pollutants in a high performance jet engine airport was investigated. Three spatial scales were considered: i) a downwind receptor site, ii) close to the airstrip, iii) personal monitoring. Particle number, surface area, mass concentrations and distributions were measured as well as inorganic and organic fractions, ionic fractions and Polycyclic Aromatic Hydrocarbons. Particle number distribution measured at a receptor site presents a mode of 80 nm and an average total concentration of 6.5 × 103 part. cm−3; the chemical analysis shows that all the elements may be attributed to long-range transport from the sea. Particle number concentrations in the proximity of the airstrip show short term peaks during the working day mainly related to takeoff, landing and pre-flight operations of jet engines. Personal exposure of workers highlights a median number concentration of 2.5 × 104 part. cm−3 and 1.7 × 104 part. cm−3 for crew chief and hangar operator. - Highlights: ► Air quality measures were performed at different spatial scales in an aviation base. ► Exposure to Polycyclic Aromatic Hydrocarbons was estimated. ► Particles at downwind receptor site show a marine origin typical of a coastal site. ► Main exposure peaks are related to pre-flight operations of jet engine aircrafts. ► Crew chief are exposed to highest concentrations even if these were not worrisome. - A negligible impact of a high performance jet engine airport, in terms of airborne particles and other pollutants, was measured through an experimental campaign at three spatial scales.

  16. Measurement of airborne bacteria and endotoxin generated during dental cleaning.

    Science.gov (United States)

    Dutil, Steve; Meriaux, Anne; de Latremoille, Marie-Chantale; Lazure, Louis; Barbeau, Jean; Duchaine, Caroline

    2009-02-01

    Dynamic dental instruments generate abundant aerosols in the work environment. Dental unit waterlines (DUWL) support a large microbial population and can be a significant source of bioaerosols generated during dental treatments. This study was conducted to characterize bioaerosol generation during dental treatments performed in standardized conditions. Culture-based method (R2A, and blood agar with and without O2) and fluorescence microscopy were used. Dental cleaning procedures were performed in an isolated treatment room with controlled ventilation rate. Andersen microbial samplers were used to collect culturable bioaerosols generated before (baseline), during, and after 2 hr of dental treatments. Inhalable dust samplers were used to measure total bioaerosols content in dental hygienist's and patients' breathing zones. AGI-30 were used for the collection of the endotoxin. The use of fluorescence microscopy in combination with culture demonstrated that dental staff and patients were exposed to up to 1.86 E+05 bacteria/m(3) generated during treatments. Fortunately, bioaerosols returned to baseline within 2 hr after the dental procedures. The small diameter of the aerosols generated (< 1 microm) suggests that the risk of contact between the aerosolized bacteria and the respiratory system of exposed individuals is likely to occur. PMID:19093289

  17. Optical manipulation of airborne particles using flexible dual-beam trap

    Czech Academy of Sciences Publication Activity Database

    Brzobohatý, Oto; Šiler, Martin; Zemánek, Pavel

    Bellingham: SPIE, 2012 - (Dholakia, K.; Spalding, G.), 84582C:1-7 ISBN 978-0-8194-9175-6. [Optical Trapping and Optical Micromanipulation IX. San Diego (US), 12.08.2012-16.08.2012] R&D Projects: GA ČR GPP205/11/P294; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : Optical tweezers * Dual-beam trap * Standing wave trap * Spatial light modulator * Airborne particles * Droplets Subject RIV: BH - Optics, Masers, Lasers

  18. Particle-size distribution of fission products in airborne dust collected at Tsukuba from April to June 1986

    International Nuclear Information System (INIS)

    The radioactivity released by the reactor accident at Chernobyl was detected in surface air at Tsukuba, Japan. Gamma-spectrometry of airborne dust collected using aerodynamic separation showed higher concentrations of radionuclides in fine particles. The particle-size distribution of radionuclides changed with time. (author)

  19. The effect of airborne particles and weather conditions on pediatric respiratory infections in Cordoba, Argentine

    International Nuclear Information System (INIS)

    We studied the effect of estimated PM10 on respiratory infections in children from Cordoba, Argentine as well as the influence of weather factors, socio-economic conditions and education. We analyzed upper and lower respiratory infections and applied a time-series analysis with a quasi-Poisson distribution link function. To control for seasonally varying factors we fitted cubic smoothing splines of date. We also examined community-specific parameters and differences in susceptibility by sex. We found a significant association between particles and respiratory infections. This relationship was affected by mean temperature, atmospheric pressure and wind speed. These effects were stronger in fall, winter and spring for upper respiratory infections while for lower respiratory infections the association was significant only during spring. Low socio-economic conditions and low education levels increased the risk of respiratory infections. These findings add useful information to understand the influence of airborne particles on children health in developing countries. - Highlights: ► Few information is available on children respiratory health from developing countries. ► We modeled the association between PM10 and children's respiratory infections. ► We checked the influence of weather factors, socio-economic conditions, education and sex. ► Temperature, pressure and wind speed modified the effect of particles. ► Low socio-economic conditions and low education levels increased the risk of infections. - The concentration of airborne particles as well as low socio-economic conditions and low education levels are significant risk factors for upper and lower respiratory infections in children from Cordoba, Argentine.

  20. Laboratory testing of airborne brake wear particle emissions using a dynamometer system under urban city driving cycles

    Science.gov (United States)

    Hagino, Hiroyuki; Oyama, Motoaki; Sasaki, Sousuke

    2016-04-01

    To measure driving-distance-based mass emission factors for airborne brake wear particulate matter (PM; i.e., brake wear particles) related to the non-asbestos organic friction of brake assembly materials (pads and lining), and to characterize the components of brake wear particles, a brake wear dynamometer with a constant-volume sampling system was developed. Only a limited number of studies have investigated brake emissions under urban city driving cycles that correspond to the tailpipe emission test (i.e., JC08 or JE05 mode of Japanese tailpipe emission test cycles). The tests were performed using two passenger cars and one middle-class truck. The observed airborne brake wear particle emissions ranged from 0.04 to 1.4 mg/km/vehicle for PM10 (particles up to 10 μm (in size), and from 0.04 to 1.2 mg/km/vehicle for PM2.5. The proportion of brake wear debris emitted as airborne brake wear particles was 2-21% of the mass of wear. Oxygenated carbonaceous components were included in the airborne PM but not in the original friction material, which indicates that changes in carbon composition occurred during the abrasion process. Furthermore, this study identified the key tracers of brake wear particles (e.g., Fe, Cu, Ba, and Sb) at emission levels comparable to traffic-related atmospheric environments.

  1. Size and composition of airborne particles from pavement wear, tires, and traction sanding.

    Science.gov (United States)

    Kupiainen, Kaarle J; Tervahattu, Heikki; Räisänen, Mika; Mäkelä, Timo; Aurela, Minna; Hillamo, Risto

    2005-02-01

    Mineral matter is an important component of airborne particles in urban areas. In northern cities of the world, mineral matter dominates PM10 during spring because of enhanced road abrasion caused by the use of antiskid methods, including studded tires and traction sanding. In this study, factors that affect formation of abrasion components of springtime road dust were assessed. Effects of traction sanding and tires on concentrations, mass size distribution, and composition of the particles were studied in a test facility. Lowest particle concentrations were observed in tests without traction sanding. The concentrations increased when traction sand was introduced and continued to increase as a function of the amount of aggregate dispersed. Emissions were additionally affected by type of tire, properties of traction sand aggregate, and driving speed. Aggregates with high fragmentation resistance and coarse grain size distribution had the lowest emissions. Over 90% of PM10 was mineral particles. Mineralogy of the dust and source apportionment showed that they originated from both traction sand and pavement aggregates. The remaining portion was mostly carbonaceous and originated from tires and road bitumen. Mass size distributions were dominated by coarse particles. Contribution of fine and submicron size ranges were approximately 15 and 10% in PM10, respectively. PMID:15757329

  2. Generation of Fine Particles with Specified Characteristics

    CERN Document Server

    Ishmatov, A N; Trubnikov, A A; Ogorodnikov, S P

    2013-01-01

    The research is devoted to the generation of fine particles and droplet flows with specified characteristics for a wide range of scientific problems. The aspects of aerodynamic fine atomization and the effects of atomizing gas density, gas velocity and mass flow rate, and liquid film thickness on the droplet formation are investigated. The hypothesis of highly efficient utilization of secondary droplets from a coarse polydisperse flow to produce fine particles is suggested and experimentally confirmed. A prototype device to implement the idea of separating the desired droplets fraction from a primary polydisperse flow was developed. In the case of fine liquid atomization, the developed spraying system enabled an increase in the gas-droplet flow concentration. The possibility of producing particles with different dispersiveness and morphology by employing the methods of spray separation and dilute solution atomization is demonstrated. The criteria of the system settings to generate the droplet flow with specif...

  3. Treatment of airborne asbestos and asbestos-like microfiber particles using atmospheric microwave air plasma

    International Nuclear Information System (INIS)

    Highlights: → We use atmospheric microwave air plasma to treat ceramic fiber and stainless fiber as asbestos alike micro fiber particle. → Spheroidization of certain type of ceramic fiber and stainless fiber particle. → The evaluation of the treated particles by the fiber vanishing rate. → Good fiber vanishing rate is observed for fiber particle with diameter below 10 μm. → The treatment of pure asbestos and a suggestion of the use of this method for the treatment airborne asbestos. - Abstract: Atmospheric microwave air plasma was used to treat asbestos-like microfiber particles that had two types of ceramic fiber and one type of stainless fiber. The treated particles were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experiment results showed that one type of ceramic fiber (Alumina:Silica = 1:1) and the stainless fiber were spheroidized, but the other type of ceramic fiber (Alumina:Silica = 7:3) was not. The conversion of the fibers was investigated by calculating the equivalent diameter, the aspect ratio, and the fiber content ratio. The fiber content ratio in various conditions showed values near zero. The relationship between the normalized fiber vanishing rate and the energy needed to melt the particles completely per unit surface area of projected particles, which is defined as η, was examined and seen to indicate that the normalized fiber vanishing rate decreased rapidly with the increase in η. Finally, some preliminary experiments for pure asbestos were conducted, and the analysis via XRD and phase-contrast microscopy (PCM) showed the availability of the plasma treatment.

  4. Primary Particles from different bubble generation techniques

    Science.gov (United States)

    Butcher, A. C.; King, S. M.; Rosenoern, T.; Nilsson, E. D.; Bilde, M.

    2011-12-01

    Sea spray aerosols (SSA) are of major interest to global climate models due to large uncertainty in their emissions and ability to form Cloud Condensation Nuclei (CCN). In general, SSA are produced from wind breaking waves that entrain air and cause bubble bursting on the ocean surface. Preliminary results are presented for bubble generation, bubble size distribution, and CCN activity for laboratory generated SSA. In this study, the major processes of bubble formation are examined with respect to particle emissions. It has been suggested that a plunging jet closely resembles breaking wave bubble entrainment processes and subsequent bubble size distributions (Fuentes, Coe et al. 2010). Figure 1 shows the different particle size distributions obtained from the various bubble generation techniques. In general, frits produce a higher concentration of particles with a stronger bimodal particle size distribution than the various jet configurations used. The experiments consist of a stainless steel cylinder closed at both ends with fittings for aerosol sampling, flow connections for the recirculating jet, and air supply. Bubble generation included a recirculating jet with 16 mm or 4 mm nozzles, a stainless steel frit, or a ceramic frit. The chemical composition of the particles produced via bubble bursting processes has been probed using particle CCN activity. The CCN activity of sodium chloride, artificial sea salt purchased from Tropic Marin, and laboratory grade artificial sea salt (Kester, Duedall et al. 1967) has been compared. Considering the the limits of the shape factor as rough error bars for sodium chloride and bubbled sea salt, the CCN activity of artificial sea salt, Tropic Marin sea salt, and sodium chloride are not significantly different. This work has been supported by the Carlsberg Foundation.

  5. Measuring the trace elemental composition of size-resolved airborne particles.

    Science.gov (United States)

    Herner, Jorn D; Green, Peter G; Kleeman, Michael J

    2006-03-15

    A new method to measure the trace elemental composition of size-resolved airborne particles that uses acetone extraction followed by ICPMS analysis is compared to three other established methods: copper anode XRF, molybdenum anode XRF, and an ICPMS method that uses HF digestion. The method detection limit (MDL), accuracy, and precision of each method is studied through the analysis of ambient samples collected in California. The MDLs of the new acetone-ICPMS method are similar to MDLs for the established HF-ICPMS method. Both sets of ICPMS MDLs are 1-3 orders of magnitude lower than XRF MDLs for approximately 50 elements other than the light crustal elements such as silicon, sulfur, calcium, and zinc. The accuracy of the acetone-ICPMS method was verified by comparison to measurements made using ion chromatography and the HF-ICPMS method. The acetone-ICPMS analysis method was more precise than the conventional HF-ICPMS method for collocated measurements. Both ICPMS methods were more precise than XRF for most elements. The size distribution of 21 elements contained in ambient particles collected with cascade impactors could be measured with good precision using the new acetone-ICPMS analysis method: lithium, sulfur, potassium, titanium, vanadium, manganese, iron, gallium, germanium, arsenic, selenium, bromine, rubidium, strontium, cadmium, tin, antimony, barium, thallium, lead, and bismuth. It is likely that the size distribution of an additional 9 elements could also be measured when concentrations are sufficiently high: phosphorus, molybdenum, niobium, palladium, cesium, europium, holmium, platinum, and uranium. None of the conventional methods were able to measure the size distribution of these elements with acceptable precision under the conditions studied. The new acetone-ICPMS method should provide useful data for the study of the health effects of airborne particles. PMID:16570617

  6. Chemical and isotopic properties and origin of coarse airborne particles collected by passive samplers in industrial, urban, and rural environments

    Science.gov (United States)

    Guéguen, Florence; Stille, Peter; Dietze, Volke; Gieré, Reto

    2012-12-01

    Passive air samplers have been installed in industrial, urban, rural and remote forested environments in order to collect coarse airborne particles for subsequent chemical characterization. To identify principal polluting sources, isotopic tracers, such as Sr, Nd and Pb isotopic ratios, have been used. The mass deposition rates (MDRs) of trace metals, determined for each of the studied environments, clearly indicate that industrial and traffic sites are especially affected by air pollution. Elements such as V, Pb, Fe, Cr, Co, Mo, Cd, Ni, As, Sb and Zn are notably enriched in samples from industrial zones, whereas V, Mn, Ba, Sr, Al, U, Th, rare earth elements (REE), Zr, Y, Cs, Rb, Sb, Sn and Cu are principal components of the airborne particles collected close to areas influenced by heavy traffic. The chemical/isotopic baseline composition derived from the airborne particles is the result of mixing of particles from different industrial sources, traffic and fertilizers. The monthly analysis of trace-metal MDRs of the collected airborne particle samples from different stations around the industrial zone allows for the detection of distinct atmospheric dust-deposition events during the year, characterized by high MDRs. "Natural" dusts from regional soil re-suspension, including from more distant regions like the Sahara desert, might overprint the regional atmospheric baseline composition, as suggested by trace metal trajectories in ternary diagrams and by Sr, Nd and Pb isotope data.

  7. Differences in airborne particle and gaseous concentrations in urban air between weekdays and weekends

    International Nuclear Information System (INIS)

    Airborne particle number concentrations and size distributions as well as CO and NOx concentrations monitored at a site within the central business district of Brisbane, Australia were correlated with the traffic flow rate on a nearby freeway with the aim of investigating differences between weekday and weekend pollutant characteristics. Observations over a 5-year monitoring period showed that the mean number particle concentration on weekdays was (8.8±0.1)x103 cm-3 and on weekends (5.9±0.2)x103 cm-3 - a difference of 47%. The corresponding mean particle number median diameters during weekdays and weekends were 44.2±0.3 and 50.2±0.2 nm, respectively. The differences in mean particle number concentration and size between weekdays and weekends were found to be statistically significant at confidence levels of over 99%. During a 1-year period of observation, the mean traffic flow rate on the freeway was 14.2x104 and 9.6x104 vehicles per weekday and weekend day, respectively - a difference of 48%. The mean diurnal variations of the particle number and the gaseous concentrations closely followed the traffic flow rate on both weekdays and weekends (correlation coefficient of 0.86 for particles). The overall conclusion, as to the effect of traffic on concentration levels of pollutant concentration in the vicinity of a major road (about 100 m) carrying traffic of the order of 105 vehicles per day, is that about a 50% increase in traffic flow rate results in similar increases of CO and NOx concentrations and a higher increase of about 70% in particle number concentration. (author)

  8. Using proximate analysis to characterize airborne dust generation from bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Page, S.J.; Organiscak, J.A.

    2005-11-01

    Prolonged exposure to airborne respirable coal dust is responsible for coal workers pneumoconiosis (CWP), commonly called black lung. Health research studies have identified that the prevalence and severity of CWP are directly related to both the amount of dust exposure and the coal rank. The amount of airborne respirable dust (ARD) smaller than 10 micrometers generated from breakage of different coals varies widely. To investigate the cause, researchers for the National Institute for Occupational Safety and Health (NIOSH) have conducted experiments to identify the causes of airborne respirable dust liberation. Laboratory crushing experiments were conducted on a range of low to high volatile bituminous coals from eight mines. The results indicate that the proximate analysis of a coal sample can provide a very good indicator of the potential for a dust problem. For application to the coal mining, processing, and utilization industries, data from 977 US coal seams compiled by the Department of Energy (DoE) has been used to calculate this dust generation potential from an equation based on the NIOSH measured data. A simple procedure for this calculation is provided. 1 fig.

  9. Fabrication and characterization of thermally actuated micromechanical resonators for airborne particle mass sensing: II. Device fabrication and characterization

    International Nuclear Information System (INIS)

    This paper, the second of two parts, presents extensive measurement and characterization results on fabricated thermally actuated single-crystal silicon MEMS resonators analyzed in part I. The resonators have been fabricated using a single mask process on SOI substrates. Resonant frequencies in a few hundreds of kHz to a few MHz and equivalent motional conductances as high as 102 mA V−1 have been measured for the fabricated resonators. The measurement results have been compared to the resonator characteristics predicted by the model developed in part I showing a good agreement between the two. Despite the relatively low frequencies, high quality factors (Q) of the order of a few thousand have been measured for the resonators under atmospheric pressure. The mass sensitivities of some of the resonators were characterized by embedding them in a custom-made test setup and deposition of artificially generated aerosol particles with known size and composition. The resulting measured mass sensitivities are of the order of tens to hundreds of Hz ng−1 and are in agreement with the expected values based on the resonator's physical dimensions. Finally, measurement of mass density of arbitrary airborne particles in the surrounding lab environment has been demonstrated

  10. Alternate particle removal technologies for the Airborne Activity Confinement System at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, J.E.; Adkins, C.L.J.; Gelbard, F. [Sandia National Labs., Albuquerque, NM (United States)

    1991-09-01

    This report presents a review of the filtration technologies available for the removal of particulate material from a gas stream. It was undertaken to identify alternate filtration technologies that may be employed in the Airborne Activity Confinement System (AACS) at the Savannah River Plant. This report is organized into six sections: (1) a discussion of the aerosol source term and its definition, (2) a short discussion of particle and gaseous contaminant removal mechanisms, (3) a brief overview of particle removal technologies, (4) a discussion of the existing AACS and its potential shortcomings, (5) an enumeration of issues to be addressed in upgrading the AACS, and, (6) a detailed discussion of the identified technologies. The purpose of this report is to identity available options to the existing particle removal system. This system is in continuous operation during routine operation of the reactor. As will be seen, there are a number of options and the selection of any technology or combination of technologies will depend on the design aerosol source term (yet to be appropriately defined) as well as the flow requirements and configuration. This report does not select a specific technology. It focuses on particulate removal and qualitatively on the removal of radio-iodine and mist elimination. Candidate technologies have been selected from industrial and nuclear gas cleaning applications.

  11. Alternate particle removal technologies for the Airborne Activity Confinement System at the Savannah River Site

    International Nuclear Information System (INIS)

    This report presents a review of the filtration technologies available for the removal of particulate material from a gas stream. It was undertaken to identify alternate filtration technologies that may be employed in the Airborne Activity Confinement System (AACS) at the Savannah River Plant. This report is organized into six sections: (1) a discussion of the aerosol source term and its definition, (2) a short discussion of particle and gaseous contaminant removal mechanisms, (3) a brief overview of particle removal technologies, (4) a discussion of the existing AACS and its potential shortcomings, (5) an enumeration of issues to be addressed in upgrading the AACS, and, (6) a detailed discussion of the identified technologies. The purpose of this report is to identity available options to the existing particle removal system. This system is in continuous operation during routine operation of the reactor. As will be seen, there are a number of options and the selection of any technology or combination of technologies will depend on the design aerosol source term (yet to be appropriately defined) as well as the flow requirements and configuration. This report does not select a specific technology. It focuses on particulate removal and qualitatively on the removal of radio-iodine and mist elimination. Candidate technologies have been selected from industrial and nuclear gas cleaning applications

  12. The future of airborne sulfur-containing particles in the absence of fossil fuel sulfur dioxide emissions.

    Science.gov (United States)

    Perraud, Véronique; Horne, Jeremy R; Martinez, Andrew S; Kalinowski, Jaroslaw; Meinardi, Simone; Dawson, Matthew L; Wingen, Lisa M; Dabdub, Donald; Blake, Donald R; Gerber, R Benny; Finlayson-Pitts, Barbara J

    2015-11-01

    Sulfuric acid (H2SO4), formed from oxidation of sulfur dioxide (SO2) emitted during fossil fuel combustion, is a major precursor of new airborne particles, which have well-documented detrimental effects on health, air quality, and climate. Another precursor is methanesulfonic acid (MSA), produced simultaneously with SO2 during the atmospheric oxidation of organosulfur compounds (OSCs), such as dimethyl sulfide. In the present work, a multidisciplinary approach is used to examine how contributions of H2SO4 and MSA to particle formation will change in a large coastal urban area as anthropogenic fossil fuel emissions of SO2 decline. The 3-dimensional University of California Irvine-California Institute of Technology airshed model is used to compare atmospheric concentrations of gas phase MSA, H2SO4, and SO2 under current emissions of fossil fuel-associated SO2 and a best-case futuristic scenario with zero fossil fuel sulfur emissions. Model additions include results from (i) quantum chemical calculations that clarify the previously uncertain gas phase mechanism of formation of MSA and (ii) a combination of published and experimental estimates of OSC emissions, such as those from marine, agricultural, and urban processes, which include pet waste and human breath. Results show that in the zero anthropogenic SO2 emissions case, particle formation potential from H2SO4 will drop by about two orders of magnitude compared with the current situation. However, particles will continue to be generated from the oxidation of natural and anthropogenic sources of OSCs, with contributions from MSA and H2SO4 of a similar order of magnitude. This could be particularly important in agricultural areas where there are significant sources of OSCs. PMID:26483454

  13. Determination of chemical composition of individual airborne particles by SEM/EDX and micro-Raman spectrometry: A review

    Science.gov (United States)

    Stefaniak, E. A.; Buczynska, A.; Novakovic, V.; Kuduk, R.; Van Grieken, R.

    2009-04-01

    The strategies for sampling and analysis by SEM/EDX and micro-Raman spectrometry for individual airborne particles analysis as applied at the University of Antwerp (Belgium) by the MITAC group have been reviewed. Microbeam techniques provide detailed information concerning the origin, formation, transport, reactivity, transformation reactions and environmental impact of particulate matter. Moreover, some particles of certain chemical properties have been recognized as a threat for human health and cultural heritage objects. However, the small sizes of particles result in specific problems with respect to single particle analysis. Development of equipment and software for improvement of analysis and quantification are reported.

  14. 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

  15. Airborne observations of new particle formation events in the boundary layer using a Zeppelin

    Science.gov (United States)

    Lampilahti, Janne; Manninen, Hanna E.; Nieminen, Tuomo; Mirme, Sander; Pullinen, Iida; Yli-Juuti, Taina; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Lehtipalo, Katrianne; Ehn, Mikael; Mentel, Thomas F.; Petäjä, Tuukka; Kulmala, Markku

    2014-05-01

    Atmospheric new particle formation (NPF) is a frequent and ubiquitous process in the atmosphere and a major source of newly formed aerosol particles [1]. However, it is still unclear how the aerosol particle distribution evolves in space and time during an NPF. We investigated where in the planetary boundary layer does NPF begin and how does the aerosol number size distribution develop in space and time during it. We measured in Hyytiälä, southern Finland using ground based and airborne measurements. The measurements were part of the PEGASOS project. NPF was studied on six scientific flights during spring 2013 using a Zeppelin NT class airship. Ground based measurements were simultaneously conducted at SMEAR II station located in Hyytiälä. The flight profiles over Hyytiälä were flown between sunrise and noon during the growth of the boundary layer. The profiles over Hyytiälä covered vertically a distance of 100-1000 meters reaching the mixed layer, stable (nocturnal) boundary layer and the residual layer. Horizontally the profiles covered approximately a circular area of four kilometers in diameter. The measurements include particle number size distribution by Neutral cluster and Air Ion Spectrometer (NAIS), Differential Mobility Particle Sizer (DMPS) and Particle Size Magnifier (PSM) [2], meteorological parameters and position (latitude, longitude and altitude) of the Zeppelin. Beginning of NPF was determined from an increase in 1.7-3 nm ion concentration. Height of the mixed layer was estimated from relative humidity measured on-board the Zeppelin. Particle growth rate during NPF was calculated. Spatial inhomogeneities in particle number size distribution during NPF were located and the birthplace of the particles was estimated using the growth rate and trajectories. We observed a regional NPF event that began simultaneously and evolved uniformly inside the mixed layer. In the horizontal direction we observed a long and narrow high concentration plume of

  16. Aerosol-generated mesoporous silicon oxycarbide particles

    International Nuclear Information System (INIS)

    Aerosol-generated mesoporous organosilica submicronic spheres have been converted into porous silicon oxycarbide (SiCO) glasses by pyrolysis at 1000 grad C in an inert atmosphere. Spherical mesoporous particles obtained from acidic solutions of 1,2-bis(triethoxysilyl) ethane and Pluronic F127 structuring agent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption/desorption, and multi nuclear solid-state magic-angle spinning (MAS) NMR. These particles were then pyrolyzed at 1000 grad C and transformed into a SiCO phase as evidenced by 29Si MAS NMR, while TEM shows preserved mesoporosity, unfortunately difficult to access owing to the presence of an outer layer of dense silica. (authors)

  17. Instrument for Long-Path Spectral Extinction Measurements in Air: Application to Sizing of Airborne Particles

    Science.gov (United States)

    Paganini, Enrico; Trespidi, Franco; Ferri, Fabio

    2001-08-01

    A novel instrument that is capable of taking spectral extinction measurements over long optical paths (approximately 1 -100 m) in the UV, visible, and IR ranges is described. The instrument is fully automated, and the extinction spectrum is acquired in almost real time (approximately 5 -10 s) with a resolution of ~3 nm. Its sensitivity and accuracy were estimated by tests carried out in a clean room that showed that, for optical paths between 50 and 100 m, the extinction coefficient can be detected at levels of ~10-5 m-1 . Tests carried out on calibrated latex particles showed that, when it was combined with an appropriate inversion method, the technique could be profitably applied to characterize airborne particulate distributions. By carrying out measurements over optical paths of ~100 m, the instrument is also capable of detecting extinction coefficients that are due to aerosol concentrations well below the limits imposed by the European Economic Community for atmospheric pollution (150 g /m3 ). Scaled over optical paths of ~10 m, the limit imposed for particle emissions from industrial plants (10 mg /m3 ) can also be detected sensitively.

  18. Why do particle clouds generate electric charges?

    Science.gov (United States)

    Pähtz, T.; Herrmann, H. J.; Shinbrot, T.

    2010-05-01

    Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model's predictions using discrete-element simulations and a tabletop granular experiment.

  19. The white-light humidified optical particle spectrometer (WHOPS – a novel airborne system to characterize aerosol hygroscopicity

    Directory of Open Access Journals (Sweden)

    B. Rosati

    2014-07-01

    3% and maximal deviation of 9% for GFs at RH = 95%. First airborne measurements in the Netherlands observed GFs (mean value of the GF distribution at RH = 95% between 1.74 and 2.67 with a median of 1.94 for particles with a dry diameter of 500 nm. This corresponds to hygroscopicity parameters (κ between 0.21 and 0.93 with a median of 0.33. The GF distributions indicate externally mixed particles covering the whole range of GFs between ~ 1.0–3.0. On average ~ 74% of the particles were "more hygroscopic" with GFs > 1.5, ~ 15% were non- or slightly hygroscopic with GF 2, indicating influence of sea salt particles, consistent with previous ground-based particle hygroscopicity measurements in this area. The mean dry effective index of refraction for 500 nm particles was found to be rather constant with a value of 1.42 ± 0.04.

  20. Application examples of APC-03-2 and APC-03-2A airborne particle counters under various contamination conditions

    International Nuclear Information System (INIS)

    Several application examples of the airborne particle counters APC-03-2 and APC-03-2A for monitoring particle size distribution and concentration in air and other gases are described. The computer controlled fast data evaluation and storage provide efficient presentation of the measured data in a variety of table- and histogram-forms, presenting of alarm levels for each size range, observation of alarm history, etc. The device can be applied not only for clean room monitoring and laminar box testing, but also for measuring contamination in health care facilities in workshops using hazardous airborne compounds (e.g. in pharmacology), and in toxicology where the concentration of the contamination may be very high. (author)

  1. Regional monitoring of metals in the Munich metropolitan area: Comparison of biomonitoring (standardized grass culture) with deposition and airborne particles

    International Nuclear Information System (INIS)

    In the Munich metropolitan area a close association of lead (Pb) and antimony (Sb) impacts with traffic was observed in 1992 and 1993. The intercorrelation of both metals was found by samples of standardised grass cultures and was reflected by deposition sampling, too. With respect to location-specific variations, however, both methods revealed differing gradients of Pb and Sb concentrations with increasing distance from traffic. It appeared that Sb variations according to traffic implications were particularly well indicated by means of biomonitoring, while Pb variations were not indicated adequately. As a result, a special qualification of grass to selectively collect metals on airborne dust according to particle sizes was suggested. Further investigations on the correlations between metal biomonitoring, metal deposition and airborne metals in 1994 - 1996 corroborated method-specific sampling features. They in turn showed that one interference is the individual prevalence of the metals on different particle sizes. (author)

  2. Beryllium solubility in occupational airborne particles: Sequential extraction procedure and workplace application.

    Science.gov (United States)

    Rousset, Davy; Durand, Thibaut

    2016-01-01

    Modification of an existing sequential extraction procedure for inorganic beryllium species in the particulate matter of emissions and in working areas is described. The speciation protocol was adapted to carry out beryllium extraction in closed-face cassette sampler to take wall deposits into account. This four-step sequential extraction procedure aims to separate beryllium salts, metal, and oxides from airborne particles for individual quantification. Characterization of the beryllium species according to their solubility in air samples may provide information relative to toxicity, which is potentially related to the different beryllium chemical forms. Beryllium salts (BeF(2), BeSO(4)), metallic beryllium (Bemet), and beryllium oxide (BeO) were first individually tested, and then tested in mixtures. Cassettes were spiked with these species and recovery rates were calculated. Quantitative analyses with matched matrix were performed using inductively coupled plasma mass spectrometry (ICP-MS). Method Detection Limits (MDLs) were calculated for the four matrices used in the different extraction steps. In all cases, the MDL was below 4.2 ng/sample. This method is appropriate for assessing occupational exposure to beryllium as the lowest recommended threshold limit values are 0.01 µg.m(-3) in France([) (1) (]) and 0.05 µg.m(-3) in the USA.([ 2 ]) The protocol was then tested on samples from French factories where occupational beryllium exposure was suspected. Beryllium solubility was variable between factories and among the same workplace between different tasks. PMID:26327570

  3. Neural networks for the generation of sea bed models using airborne lidar bathymetry data

    Directory of Open Access Journals (Sweden)

    Kogut Tomasz

    2016-06-01

    Full Text Available Various sectors of the economy such as transport and renewable energy have shown great interest in sea bed models. The required measurements are usually carried out by ship-based echo sounding, but this method is quite expensive. A relatively new alternative is data obtained by airborne lidar bathymetry. This study investigates the accuracy of these data, which was obtained in the context of the project ‘Investigation on the use of airborne laser bathymetry in hydrographic surveying’. A comparison to multi-beam echo sounding data shows only small differences in the depths values of the data sets. The IHO requirements of the total horizontal and vertical uncertainty for laser data are met. The second goal of this paper is to compare three spatial interpolation methods, namely Inverse Distance Weighting (IDW, Delaunay Triangulation (TIN, and supervised Artificial Neural Networks (ANN, for the generation of sea bed models. The focus of our investigation is on the amount of required sampling points. This is analyzed by manually reducing the data sets. We found that the three techniques have a similar performance almost independently of the amount of sampling data in our test area. However, ANN are more stable when using a very small subset of points.

  4. Neural networks for the generation of sea bed models using airborne lidar bathymetry data

    Science.gov (United States)

    Kogut, Tomasz; Niemeyer, Joachim; Bujakiewicz, Aleksandra

    2016-06-01

    Various sectors of the economy such as transport and renewable energy have shown great interest in sea bed models. The required measurements are usually carried out by ship-based echo sounding, but this method is quite expensive. A relatively new alternative is data obtained by airborne lidar bathymetry. This study investigates the accuracy of these data, which was obtained in the context of the project `Investigation on the use of airborne laser bathymetry in hydrographic surveying'. A comparison to multi-beam echo sounding data shows only small differences in the depths values of the data sets. The IHO requirements of the total horizontal and vertical uncertainty for laser data are met. The second goal of this paper is to compare three spatial interpolation methods, namely Inverse Distance Weighting (IDW), Delaunay Triangulation (TIN), and supervised Artificial Neural Networks (ANN), for the generation of sea bed models. The focus of our investigation is on the amount of required sampling points. This is analyzed by manually reducing the data sets. We found that the three techniques have a similar performance almost independently of the amount of sampling data in our test area. However, ANN are more stable when using a very small subset of points.

  5. Modern Particle Physics Event Generation with WHIZARD

    CERN Document Server

    Reuter, J; Nejad, B Chokoufe; Kilian, W; Ohl, T; Sekulla, M; Weiss, C

    2014-01-01

    We describe the multi-purpose Monte-Carlo event generator WHIZARD for the simulation of high-energy particle physics experiments. Besides the presentation of the general features of the program like SM physics, BSM physics, and QCD effects, special emphasis will be given to the support of the most accurate simulation of the collider environments at hadron colliders and especially at future linear lepton colliders. On the more technical side, the very recent code refactoring towards a completely object-oriented software package to improve maintainability, flexibility and code development will be discussed. Finally, we present ongoing work and future plans regarding higher-order corrections, more general model support including the setup to search for new physics in vector boson scattering at the LHC, as well as several lines of performance improvements.

  6. Modern particle physics event generation with WHIZARD

    Energy Technology Data Exchange (ETDEWEB)

    Reuter, J.; Bach, F.; Chokoufe, B. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Kilian, W.; Sekulla, M. [Siegen Univ. (Germany). Dept. of Physics; Ohl, T. [Wuerzburg Univ. (Germany). Dept. of Physics and Astronomy; Weiss, C. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Siegen Univ. (Germany). Dept. of Physics

    2014-10-16

    We describe the multi-purpose Monte-Carlo event generator WHIZARD for the simulation of high-energy particle physics experiments. Besides the presentation of the general features of the program like SM physics, BSM physics, and QCD effects, special emphasis is given to the support of the most accurate simulation of the collider environments at hadron colliders and especially at future linear lepton colliders. On the more technical side, the very recent code refactoring towards a completely object-oriented software package to improve maintainability, flexibility and code development are discussed. Finally, we present ongoing work and future plans regarding higher-order corrections, more general model support including the setup to search for new physics in vector boson scattering at the LHC, as well as several lines of performance improvements.

  7. Modern particle physics event generation with WHIZARD

    International Nuclear Information System (INIS)

    We describe the multi-purpose Monte-Carlo event generator WHIZARD for the simulation of high-energy particle physics experiments. Besides the presentation of the general features of the program like SM physics, BSM physics, and QCD effects, special emphasis is given to the support of the most accurate simulation of the collider environments at hadron colliders and especially at future linear lepton colliders. On the more technical side, the very recent code refactoring towards a completely object-oriented software package to improve maintainability, flexibility and code development are discussed. Finally, we present ongoing work and future plans regarding higher-order corrections, more general model support including the setup to search for new physics in vector boson scattering at the LHC, as well as several lines of performance improvements.

  8. Compressed beam directed particle nuclear energy generator

    International Nuclear Information System (INIS)

    This invention relates to the generation of energy from the fusion of atomic nuclei which are caused to travel towards each other along collision courses, orbiting in common paths having common axes and equal radii. High velocity fusible ion beams are directed along head-on circumferential collision paths in an annular zone wherein beam compression by electrostatic focusing greatly enhances head-on fusion-producing collisions. In one embodiment, a steady radial electric field is imposed on the beams to compress the beams and reduce the radius of the spiral paths for enhancing the particle density. Beam compression is achieved through electrostatic focusing to establish and maintain two opposing beams in a reaction zone

  9. Health effects of daily airborne particle dose in children: Direct association between personal dose and respiratory health effects

    International Nuclear Information System (INIS)

    Air pollution is a widespread health problem associated with respiratory symptoms. Continuous exposure monitoring was performed to estimate alveolar and tracheobronchial dose, measured as deposited surface area, for 103 children and to evaluate the long-term effects of exposure to airborne particles through spirometry, skin prick tests and measurement of exhaled nitric oxide (eNO). The mean daily alveolar deposited surface area dose received by children was 1.35 × 103 mm2. The lowest and highest particle number concentrations were found during sleeping and eating time. A significant negative association was found between changes in pulmonary function tests and individual dose estimates. Significant differences were found for asthmatics, children with allergic rhinitis and sensitive to allergens compared to healthy subjects for eNO. Variation is a child's activity over time appeared to have a strong impact on respiratory outcomes, which indicates that personal monitoring is vital for assessing the expected health effects of exposure to particles. -- Highlights: •Particle dose was estimated through personal monitoring on more than 100 children. •We focused on real-time daily dose of particle alveolar deposited surface area. •Spirometry, skin prick and exhaled Nitric Oxide tests were performed. •Negative link was found between changes in pulmonary functions and individual doses. •A child's lifestyle appeared to have a strong impact on health respiratory outcomes. -- The respiratory health effects of daily airborne particle dose on children through personal monitoring

  10. Characterizing the impact of urban emissions on regional aerosol particles: airborne measurements during the MEGAPOLI experiment

    Science.gov (United States)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouche, N.; Pichon, J.-M.; Bourianne, T.; Gomes, L.; Prevot, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2014-02-01

    The MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris, using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), giving detailed information on the non-refractory submicron aerosol species. The mass concentration of black carbon (BC), measured by a particle absorption soot photometer (PSAP), was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA), BC, and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (-log(NOx / NOy)). Plotting the equivalent ratios of different organic aerosol species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA) formation. Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in London, Mexico City, and in New England, USA. Using the measured SOA volatile organic compounds (VOCs) species together with organic aerosol formation

  11. Short-term mechanisms of toxic action of airborne particulates underlie dose-rate dependent health risks and support control of one-hour airborne particle levels

    Energy Technology Data Exchange (ETDEWEB)

    Michaels, R.A.; Kleinman, M.T.

    1999-07-01

    Twenty-four-hour airborne particle mass levels permissible under the NAAQS have been associated with mortality and morbidity in communities, motivating reconsideration of the standard. Reports of shorter-term mechanisms of toxic action exerted by airborne PM and PM constituents are emerging. The mechanisms are diverse, but have in common a short time frame of toxic action, from minutes to hours. In view of documented PM excursions also lasting minutes to hours, this study inquires whether such short-term mechanisms might contribute to explaining daily morbidity and mortality. Toxicology experiments have demonstrated the harmfulness of brief exposure to PM levels in the range of observed excursions. This suggests that toxicological processes initiated by short-term inhalation of PM may exert clinically important effects, and that weak associations of 24-hour-average particle mass with mortality and morbidity may represent artifacts of stronger, shorter-term associations whose full magnitude remains to be quantified. In one study, the area of lung surface developing lesions was elevated in rats breathing the same four-hour dose of aerosols, when the four-hour average rate of aerosol delivery included a short-term (five-minute) burst fifty percent above the average dose rate. Elevations were observed with each of two aerosols tested. The magnitude of the effect was higher with one of the two aerosols, whose dose rate included four excursions rather than just one excursion. Particulate matter inhaled or instilled intratracheally has produced morbidity in animals, including apnea and electrophysiological effects in dogs. Other studies reveal that PM can kill rats via electrophysiological and possibly other mechanisms. PM has also adversely affected asthmatic people in controlled clinical settings during exercise or, in one study, at rest.

  12. Organic compounds present in airborne particles stimulate superoxide production and DNA fragmentation: role of NOX and xanthine oxidase in animal tissues.

    Science.gov (United States)

    Busso, Iván Tavera; Silva, Guillermo Benjamín; Carreras, Hebe Alejandra

    2016-08-01

    Suspended particulate matter trigger the production of reactive oxygen species. However, most of the studies dealing with oxidative damage of airborne particles focus on the effects of individual compounds and not real mixtures. In order to study the enzymatic superoxide production resulting from the exposition to a complex mixture, we derived organic extracts from airborne particles collected daily in an urban area and exposed kidney, liver, and heart mammal tissues. After that, we measured DNA damage employing the comet assay. We observed that in every tissue, NADPH oxidase and xanthine oxidase were involved in O2 (-) production when they were exposed to the organic extracts, as the lucigenin's chemiluminescence decays when enzymes were inhibited. The same trend was observed with the percentage of cells with comets, since DNA damage was higher when they were exposed to same experimental conditions. Our data allow us to hypothesize that these enzymes play an important role in the oxidative stress produced by PAHs and that there is a mechanism involving them in the O2 (-)generation. PMID:27180836

  13. Effect of reactive oxygen species (ROS) generating system for control of airborne microorganisms in meat processing environment

    Science.gov (United States)

    The effectiveness of reactive oxygen species (ROS) generating AirOcare equipment on the reduction of airborne bacteria in a meat processing environment was determined. Serratia marcescens and lactic acid bacteria (Lactococcus lactis subsp. lactis and Lactobacillus plantarum) were used to artificiall...

  14. Experimental study of the response functions of direct-reading instruments measuring surface-area concentration of airborne nanostructured particles

    Science.gov (United States)

    Bau, Sébastien; Witschger, Olivier; Gensdarmes, François; Thomas, Dominique

    2009-05-01

    An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment to move forward our understanding of the hazards, the actual exposures in the workplace, and the limits of engineering controls and personal protective equipment with regard to NP. As a consequence, generating airborne NP with controlled properties constitutes an important challenge. In parallel, toxicological studies have been carried out, and most of them support the concept that surface-area could be a relevant metric for characterizing exposure to airborne NP [1]. To provide NP surface-area concentration measurements, some direct-reading instruments have been designed, based on attachment rate of unipolar ions to NP by diffusion. However, very few information is available concerning the performances of these instruments and the parameters that could affect their responses. In this context, our work aims at characterizing the actual available instruments providing airborne NP surface-area concentration. The instruments (a- LQ1-DC, Matter Engineering; b-AeroTrak™ 9000, TSI; c- NSAM, TSI model 3550;) are thought to be relevant for further workplace exposure characterization and monitoring. To achieve our work, an experimental facility (named CAIMAN) was specially designed, built and characterized.

  15. Characteristics of the fine particles generated in plasma process

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, A.; Matsubayashi, K.; Susuki, M. [Tokyo Institute of Technology, Graduate School of Science and Engineering (Japan)

    2001-07-01

    Modeling of fine particles generation in plasma process under an atmospheric pressure is investigated. Our model consists of two physical phenomena, evaporation of metal and particle growth, were studied with computer simulation. Evaporation phenomenon is simulated by lattice Boltzmann method and evaporation rate of iron is estimated. Particle growth is simulated by using general dynamic equation. Agglomerate consisting of primary particles which is taken size distribution into account is represented by fractal dimension connecting number density of primary particles. Particle size and particle size distribution at various temperatures are obtained and discussed. (authors)

  16. Physicochemical characteristics of aerosol particles generated during the milling of beryllium silicate ores: implications for risk assessment.

    Science.gov (United States)

    Stefaniak, Aleksandr B; Chipera, Steve J; Day, Gregory A; Sabey, Phil; Dickerson, Robert M; Sbarra, Deborah C; Duling, Mathew G; Lawrence, Robert B; Stanton, Marcia L; Scripsick, Ronald C

    2008-01-01

    Inhalation of beryllium dusts generated during milling of ores and cutting of beryl-containing gemstones is associated with development of beryllium sensitization and low prevalence of chronic beryllium disease (CBD). Inhalation of beryllium aerosols generated during primary beryllium production and machining of the metal, alloys, and ceramics are associated with sensitization and high rates of CBD, despite similar airborne beryllium mass concentrations among these industries. Understanding the physicochemical properties of exposure aerosols may help to understand the differential immunopathologic mechanisms of sensitization and CBD and lead to more biologically relevant exposure standards. Properties of aerosols generated during the industrial milling of bertrandite and beryl ores were evaluated. Airborne beryllium mass concentrations among work areas ranged from 0.001 microg/m(3) (beryl ore grinding) to 2.1 microg/m(3) (beryl ore crushing). Respirable mass fractions of airborne beryllium-containing particles were 80% in high-energy input areas (beryl melting, beryl grinding). Particle specific surface area decreased with processing from feedstock ores to drumming final product beryllium hydroxide. Among work areas, beryllium was identified in three crystalline forms: beryl, poorly crystalline beryllium oxide, and beryllium hydroxide. In comparison to aerosols generated by high-CBD risk primary production processes, aerosol particles encountered during milling had similar mass concentrations, generally lower number concentrations and surface area, and contained no identifiable highly crystalline beryllium oxide. One possible explanation for the apparent low prevalence of CBD among workers exposed to beryllium mineral dusts may be that characteristics of the exposure material do not contribute to the development of lung burdens sufficient for progression from sensitization to CBD. In comparison to high-CBD risk exposures where the chemical nature of aerosol

  17. Airborne measurements over the boreal forest of southern Finland during new particle formation events in 2009 and 2010

    Energy Technology Data Exchange (ETDEWEB)

    Schobesberger, S.; Vaananen, R.; Leino, K. [Helsinki Univ. (Finland). Dept. of Physics, Division of Atmospheric Sciences] [and others

    2013-06-01

    We conducted airborne observations of aerosol physical properties over the southern Finland boreal forest environment. The aim was to investigate the lower tropospheric aerosol (up to 4-km altitude) over an area of 250 by 200 km, in particular during new particle formation (NPF) events, and to address the spatial variability of aerosol number concentration and number size distribution. The regional NPF events, detected both airborne and at the ground, with air masses originating from the Arctic or northern Atlantic Ocean were studied throughout the boundary layer and throughout the area covered. Three suitable case studies are presented in more detail. In two of these studies, the concentrations of nucleation mode particles (3-10 nm in diameter) were found considerably higher (up to a factor of 30) in the upper parts of the planetary boundary layer compared to ground-based measurements during the nucleation events. The observed vertical variation can be connected to boundary layer dynamics and interactions between the boundary layer and the lower free troposphere, likely yielding high concentrations of newly formed aerosol particles. Our results suggest that nucleation does not necessarily occur close to the surface. In one presented case we found evidence of NPF occurring in a limited area above cloud, in the complete absence of a regional NPF event. (orig.)

  18. PHIPS-HALO: the airborne Particle Habit Imaging and Polar Scattering probe - Part 1: Design and operation

    Science.gov (United States)

    Abdelmonem, Ahmed; Järvinen, Emma; Duft, Denis; Hirst, Edwin; Vogt, Steffen; Leisner, Thomas; Schnaiter, Martin

    2016-07-01

    The number and shape of ice crystals present in mixed-phase and ice clouds influence the radiation properties, precipitation occurrence and lifetime of these clouds. Since clouds play a major role in the climate system, influencing the energy budget by scattering sunlight and absorbing heat radiation from the earth, it is necessary to investigate the optical and microphysical properties of cloud particles particularly in situ. The relationship between the microphysics and the single scattering properties of cloud particles is usually obtained by modelling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. There is a demand to obtain both information correspondently and simultaneously for individual cloud particles in their natural environment. For evaluating the average scattering phase function as a function of ice particle habit and crystal complexity, in situ measurements are required. To this end we have developed a novel airborne optical sensor (PHIPS-HALO) to measure the optical properties and the corresponding microphysical parameters of individual cloud particles simultaneously. PHIPS-HALO has been tested in the AIDA cloud simulation chamber and deployed in mountain stations as well as research aircraft (HALO and Polar 6). It is a successive version of the laboratory prototype instrument PHIPS-AIDA. In this paper we present the detailed design of PHIPS-HALO, including the detection mechanism, optical design, mechanical construction and aerodynamic characterization.

  19. Toxic effects of indoor and outdoor airborne particles relevant to carcinogenesis.

    NARCIS (Netherlands)

    Heussen, G.A.H.

    1993-01-01

    The mutagenicity of indoor and outdoor airborne particulate matter (APM) has been demonstrated by previous in vitro studies (Alink et al., 1983; Van Houdt et al., 1984, 1986, 1987). The aim of the present thesis was to contribute to a better understanding of the mode of action of AIM in the pathogen

  20. Particle beam. Cancer treatment in next generation

    International Nuclear Information System (INIS)

    This feature article summarizes the present and future aspects of particle therapy of cancers in Japan. It contains the Interview article for carbon particle therapy by HIMAC (Heavy Ion Medical Accelerator in Chiba); Facilities for the therapy-present and future for diffusion; History of the carbon beam treatment in NIRS (National Institute of Radiological Sciences, Chiba); Plans for a facility unit for proton beam therapy of cancer in Fukui Pref. for the regional diffusion; a Center of Excellence program in Gunma University for forefront cancer therapy; and Technology of equipments supporting the particle beam therapy in manufacturers of Sumitomo Heavy Industries, Ltd., Toshiba Japan, Hitachi, and Mitsubishi Electric Corp. There are 6 facilities in total for the particle beam therapy of cancer in Japan. Although the diffusion of radiation therapy in Japan is as low as less than 30% in the whole cancer treatments, the particle beam therapy, an advanced form of radiotherapy, is on the top of the world. (T.I.)

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

    Directory of Open Access Journals (Sweden)

    Pietrodangelo A.

    2013-04-01

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

  2. Comparison of Three Real-Time Measurement Methods for Airborne Ultrafine Particles in the Silicon Alloy Industry.

    Science.gov (United States)

    Kero, Ida Teresia; Jørgensen, Rikke Bramming

    2016-01-01

    The aim of this study was to compare the applicability and the correlation between three commercially available instruments capable of detection, quantification, and characterization of ultrafine airborne particulate matter in the industrial setting of a tapping area in a silicon alloy production plant. The number concentration of ultrafine particles was evaluated using an Electric Low Pressure Impactor (ELPI(TM)), a Fast Mobility Particle Sizer (FMPS(TM)), and a Condensation Particle Counter (CPC). The results are discussed in terms of particle size distribution and temporal variations linked to process operations. The instruments show excellent temporal covariation and the correlation between the FMPS and ELPI is good. The advantage of the FMPS is the excellent time- and size resolution of the results. The main advantage of the ELPI is the possibility to collect size-fractionated samples of the dust for subsequent analysis by, for example, electron microscopy. The CPC does not provide information about the particle size distribution and its correlation to the other two instruments is somewhat poor. Nonetheless, the CPC gives basic, real-time information about the ultrafine particle concentration and can therefore be used for source identification. PMID:27598180

  3. Comparison of Three Real-Time Measurement Methods for Airborne Ultrafine Particles in the Silicon Alloy Industry

    Directory of Open Access Journals (Sweden)

    Ida Teresia Kero

    2016-09-01

    Full Text Available The aim of this study was to compare the applicability and the correlation between three commercially available instruments capable of detection, quantification, and characterization of ultrafine airborne particulate matter in the industrial setting of a tapping area in a silicon alloy production plant. The number concentration of ultrafine particles was evaluated using an Electric Low Pressure Impactor (ELPITM, a Fast Mobility Particle Sizer (FMPSTM, and a Condensation Particle Counter (CPC. The results are discussed in terms of particle size distribution and temporal variations linked to process operations. The instruments show excellent temporal covariation and the correlation between the FMPS and ELPI is good. The advantage of the FMPS is the excellent time- and size resolution of the results. The main advantage of the ELPI is the possibility to collect size-fractionated samples of the dust for subsequent analysis by, for example, electron microscopy. The CPC does not provide information about the particle size distribution and its correlation to the other two instruments is somewhat poor. Nonetheless, the CPC gives basic, real-time information about the ultrafine particle concentration and can therefore be used for source identification.

  4. Adaptive Slope Filtering of Airborne LiDAR Data in Urban Areas for Digital Terrain Model (DTM Generation

    Directory of Open Access Journals (Sweden)

    Junichi Susaki

    2012-06-01

    Full Text Available A filtering algorithm is proposed that accurately extracts ground data from airborne light detection and ranging (LiDAR measurements and generates an estimated digital terrain model (DTM. The proposed algorithm utilizes planar surface features and connectivity with locally lowest points to improve the extraction of ground points (GPs. A slope parameter used in the proposed algorithm is updated after an initial estimation of the DTM, and thus local terrain information can be included. As a result, the proposed algorithm can extract GPs from areas where different degrees of slope variation are interspersed. Specifically, along roads and streets, GPs were extracted from urban areas, from hilly areas such as forests, and from flat area such as riverbanks. Validation using reference data showed that, compared with commercial filtering software, the proposed algorithm extracts GPs with higher accuracy. Therefore, the proposed filtering algorithm effectively generates DTMs, even for dense urban areas, from airborne LiDAR data.

  5. Airborne Biogenic Particles in the Snow of the Cities of the Russian Far East as Potential Allergic Compounds

    Directory of Open Access Journals (Sweden)

    Kirill S. Golokhvast

    2014-01-01

    Full Text Available This paper presents an analysis of airborne biogenic particles (1 mkm–1 mm found in the snow in several cities of the Russian Far East during 2010–2013. The most common was vegetational terraneous detritus (fragments of tree and grass leaves followed by animal hair, small insects and their fragments, microorganisms of aeroplankton, and equivocal biological garbage. Specific components were found in samples from locations close to bodies of water such as fragments of algae and mollusc shells and, marine invertebrates (needles of sea urchins and shell debris of arthropods. In most locations across the Far East (Vladivostok, Khabarovsk, Blagoveshchensk, and Ussuriysk, the content of biogenic particles collected in the winter did not exceed 10% of the total particulate matter, with the exception of Birobidzhan and the nature reserve Bastak, where it made up to 20%. Most of all biogenic compounds should be allergic: hair, fragments of tree and grass leaves, insects, and microorganisms.

  6. Airborne biogenic particles in the snow of the cities of the Russian Far East as potential allergic compounds.

    Science.gov (United States)

    Golokhvast, Kirill S

    2014-01-01

    This paper presents an analysis of airborne biogenic particles (1 mkm-1 mm) found in the snow in several cities of the Russian Far East during 2010-2013. The most common was vegetational terraneous detritus (fragments of tree and grass leaves) followed by animal hair, small insects and their fragments, microorganisms of aeroplankton, and equivocal biological garbage. Specific components were found in samples from locations close to bodies of water such as fragments of algae and mollusc shells and, marine invertebrates (needles of sea urchins and shell debris of arthropods). In most locations across the Far East (Vladivostok, Khabarovsk, Blagoveshchensk, and Ussuriysk), the content of biogenic particles collected in the winter did not exceed 10% of the total particulate matter, with the exception of Birobidzhan and the nature reserve Bastak, where it made up to 20%. Most of all biogenic compounds should be allergic: hair, fragments of tree and grass leaves, insects, and microorganisms. PMID:25140327

  7. Adaptive Slope Filtering of Airborne LiDAR Data in Urban Areas for Digital Terrain Model (DTM) Generation

    OpenAIRE

    Junichi Susaki

    2012-01-01

    A filtering algorithm is proposed that accurately extracts ground data from airborne light detection and ranging (LiDAR) measurements and generates an estimated digital terrain model (DTM). The proposed algorithm utilizes planar surface features and connectivity with locally lowest points to improve the extraction of ground points (GPs). A slope parameter used in the proposed algorithm is updated after an initial estimation of the DTM, and thus local terrain information can be included. As a ...

  8. A study of particle generation during laser ablation withapplications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chunyi

    2005-08-12

    A study has been made of the generation of particles during laser ablation and has included size distribution measurements and observation of the formation processes. The particle size distribution with respect to different laser parameters was obtained in-line using a differential mobility analyzer (DMA) and a particle counter. The experimental results show that the particle size varies with laser energy, laser pulsewidth, ambient gas flow rate and sample properties. The results serve as a basis for controlling the size of nanoparticles generated by laser ablation. Laser shadowgraph imaging was used to study mass ejection processes and mechanisms. At higher laser irradiance, some particles were ejected in the liquid and even in the solid phase. Time-resolved images show the propagation of the shockwaves: external shockwaves propagate outward and decelerate, and internal shockwaves reflect back and forth between the gas contact surface and the sample surface. The internal shockwave is proposed to cause the ejection of liquid particles when the internal shockwave strikes the liquid molten layer. A simulation based on vapor plume expansion was carried out and provides satisfactory agreement with experimental results. Different material properties result in different particle ejection behavior:particle ejection for most materials including metals result in a conically shaped envelope for the ejected material while ejection for silicon resembles a liquid jet. The difference in density change when the materials melt was proposed to be an important factor in the different ejection behavior. The characteristics of particles generated by laser ablation have a strong influence on the chemical analysis of the irradiated sample. Large particles are more difficult to completely vaporize and ionize, and induced preferential vaporization causes fractionation (i.e. a detected chemical composition that differs from the sample material). Large particles also result in spikes in

  9. A New Electrospray Aerosol Generator with High Particle Transmission Efficiency.

    Science.gov (United States)

    Fu, Huijing; Patel, Anand C; Holtzman, Michael J; Chen, Da-Ren

    2011-01-01

    A new single-capillary electrospray (ES) aerosol generator has been developed for monodisperse particle production with maximal transmission efficiency. The new generator consists of both a spray chamber in a point-to-orifice-plate configuration and a charge reduction chamber that can hold up to 4 Nuclespot ionizers (Model P-2042, NRD Inc.). The 2 chambers are partitioned by an orifice plate. To optimize the particle transmission efficiency of the prototype, a systematic study was performed on the generator by varying the system setup and operation. Two key dimensions of the generator setup, the orifice diameter and the distance from the capillary tip to the orifice plate, were varied. Fluorescence analysis was applied to characterize the loss of ES-generated particles at different locations of the prototype. It was found that particle loss in the generator could be reduced by either increasing the orifice diameter or decreasing the distance between the capillary tip and the orifice plate. Increasing either the total radioactivity of the ionizers or the flowrate of the particle carrier gas also further decreased the particle loss in the system. The maximum particle transmission efficiency of 88.0% was obtained with the spray chamber fully opened to the charge reduction chamber, the capillary tip at the same level as the orifice plate, and 4 bipolar ionizers installed. PMID:22829715

  10. The physicochemical characterisation of microscopic airborne particles in south Wales: A review of the locations and methodologies

    International Nuclear Information System (INIS)

    As part of the NERC-URGENT thematic programme, research was undertaken into the physicochemistry and bioreactivity of microscopic airborne particulate matter in south Wales. This paper reviews the collecting and characterisation methods used in the research; some of the results obtained are shown as examples. Four main collecting locations were chosen: Cardiff (urban); Port Talbot (urban/industrial); Park Slip West coal opencast pit (industrial/rural); the Black Mountains (rural/background). Collections initially used a 30-l/min Negretti PM1 filter collection system, however in the later stages of the project increased use was made of a 1100-l/min impaction system (nicknamed the super-sucker). This latter device was developed at Harvard University USA, however was adapted and optimised at Cardiff University. Methods for the extraction of PM1 off polycarbonate filters and polyurethane substrates were developed, with particular attention being paid to minimise physical or chemical changes during the extraction, and the extracts being in an appropriate state for bioreactivity assessment. Physicochemical characterisation of the PM1 included the empirical measurement of shape and size using electron microscopy and semi-automated image analysis. The determinations of the water-soluble and -insoluble chemical components were undertaken by ion chromatography and inductive coupled plasma-mass spectrometry. The bioreactivity of south Wales airborne particles is not covered by this review

  11. Direct Deposition of Gas Phase Generated Aerosol Gold Nanoparticles into Biological Fluids - Corona Formation and Particle Size Shifts

    Science.gov (United States)

    Svensson, Christian R.; Messing, Maria E.; Lundqvist, Martin; Schollin, Alexander; Deppert, Knut; Pagels, Joakim H.; Rissler, Jenny; Cedervall, Tommy

    2013-01-01

    An ongoing discussion whether traditional toxicological methods are sufficient to evaluate the risks associated with nanoparticle inhalation has led to the emergence of Air-Liquid interface toxicology. As a step in this process, this study explores the evolution of particle characteristics as they move from the airborne state into physiological solution. Airborne gold nanoparticles (AuNP) are generated using an evaporation-condensation technique. Spherical and agglomerate AuNPs are deposited into physiological solutions of increasing biological complexity. The AuNP size is characterized in air as mobility diameter and in liquid as hydrodynamic diameter. AuNP:Protein aggregation in physiological solutions is determined using dynamic light scattering, particle tracking analysis, and UV absorption spectroscopy. AuNPs deposited into homocysteine buffer form large gold-aggregates. Spherical AuNPs deposited in solutions of albumin were trapped at the Air-Liquid interface but was readily suspended in the solutions with a size close to that of the airborne particles, indicating that AuNP:Protein complex formation is promoted. Deposition into serum and lung fluid resulted in larger complexes, reflecting the formation of a more complex protein corona. UV absorption spectroscopy indicated no further aggregation of the AuNPs after deposition in solution. The corona of the deposited AuNPs shows differences compared to AuNPs generated in suspension. Deposition of AuNPs from the aerosol phase into biological fluids offers a method to study the protein corona formed, upon inhalation and deposition in the lungs in a more realistic way compared to particle liquid suspensions. This is important since the protein corona together with key particle properties (e.g. size, shape and surface reactivity) to a large extent may determine the nanoparticle effects and possible translocation to other organs. PMID:24086363

  12. Characterization of airborne uranium from test firing of XM774 ammunition

    International Nuclear Information System (INIS)

    Pacific Northwest Laboratory conducted experiments at Aberdeen Proving Grounds, Maryland, to characterize the airborne depleted uranium (DU) resulting from the test firings of 105-mm, APFSDS-T XM774 ammunition. The goal was to obtain data pertinent to evaluations of human inhalation exposure to the airborne DU. Data was desired concerning the following: (1) size distribution of airborne DU; (2) quantity of airborne DU; (3) dispersion of airborne DU from the target vicinity; (4) amount of DU deposited on the ground; (5) solubility of airborne DU compounds in lung fluid; and (6) oxide forms of airborne and fallout DU. The experiments involved extensive air sampling for total airborne DU particulates and respirable DU particles both above the targets and at distances downwind. Fallout and fragments were collected around the target area. High-speed movies of the smoke generated from the impact of the penetrators were taken to estimate the cloud volumes. Results of the experiments are presented

  13. 激光尘埃粒子计数器反射腔偏差分析%Error Analysis of Reflecting mirror of Airborne Particle Counter

    Institute of Scientific and Technical Information of China (English)

    王卫芳

    2011-01-01

    目前激光尘埃粒子计数器的应用非常广泛,但各方面参数的选择还都不是很完善。将激光尘埃粒子计器的反射腔工作原理建立了几何模型,用数学公式表达出气溶胶粒子偏离焦点后在反射腔上的偏差,为实际生产和使用提供了依据。%Recently,The Airborne Particle Counter is used widely,however,its choose of parameters is not very perfect.In this particle,a geometric model of mirror in Airborne Particle Counter was established,expressed in mathematical formula for error in reflect cavity besause of Particles off the focus,This will offer some references to practices.

  14. Airborne dust and soil particles at the Phoenix landing site, Mars

    DEFF Research Database (Denmark)

    Madsen, M. B.; Drube, L.; Goetz, W.;

    . Because of the multiple background colors of the iSweeps the effect of the translucence of thin dust layers can be studied. This is used to estimate the rate of dust accumulation and will be used to evaluate light scattering properties of the particles. Some particles raised by the retro-rockets during...

  15. Compact Ti:Sapphire laser with its Third Harmonic Generation (THG) for an airborne ozone Differential Absorption Lidar (DIAL) transmitter

    Science.gov (United States)

    Chen, Songsheng; Storm, Mark E.; Marsh, Waverly D.; Petway, Larry B.; Edwards, William C.; Barnes, James C.

    2001-02-01

    A compact and high-pulse-energy Ti:Sapphire laser with its Third Harmonic Generation (THG) has been developed for an airborne ozone differential absorption lidar (DIAL) to study the distributions and concentrations of the ozone throughout the troposphere. The Ti:Sapphire laser, pumped by a frequency-doubled Nd:YAG laser and seeded by a single mode diode laser, is operated either at 867 nm or at 900 nm with a pulse repetition frequency of 20 Hz. High energy laser pulses (more than 110 mJ/pulse) at 867 nm or 900 nm with a desired beam quality have been achieved and utilized to generate its third harmonics at 289nm or 300nm, which are on-line and off-line wavelengths of an airborne ozone DIAL. After experimentally compared with Beta-Barium Borate (b-BaB2O4 or BBO) nonlinear crystals, two Lithium Triborate (LBO) crystals (5'5'20 mm3) are selected for the Third Harmonic Generation (THG). In this paper, we report the Ti:Sapphire laser at 900nm and its third harmonics at 300nm. The desired high ultraviolet (UV) output pulse energy is more than 30mJ at 300nm and the energy conversion efficiency from 900nm to 300nm is 30%.

  16. A unique facility to test the infectivity of human-generated airborne infections / Sidney A. Parsons

    OpenAIRE

    Parsons, Sidney Andrew

    2006-01-01

    Tuberculosis (TB), one of the world's greatest killers, is predominantly spread by the airborne route. Drug-resistant M. tuberculosis has emerged as a global public health threat despite effective drugs and disease control strategies. Little is known about M. tuberculosis transmission and the efficacy of necessary environmental (engineering) interventions for infection control; particularly in light of the global HIV/Aids epidemic. This thesis covers the development, validation...

  17. Phthalates in PM2.5 airborne particles in the Moravian-Silesian Region, Czech Republic

    OpenAIRE

    Jana Růžičková; Helena Raclavská; Konstantin Raclavský; Dagmar Juchelková

    2016-01-01

    Industrial area of the Moravian-Silesian Region (the Czech Republic) is highly polluted by air contaminants, especially emissions of particulate matter. Samples of PM2.5 particles were analysed by pyrolysis gas chromatography with mass spectrometric detection. Concentrations of phthalates were determined for the winter season, transitional period and the summer season. The relative concentrations of phthalates in PM2.5 particles have the same proportion in both heating and non-heating season:...

  18. Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates

    Directory of Open Access Journals (Sweden)

    C. D. O'Dowd

    2007-01-01

    Full Text Available A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs (50% cut from 3–5.4–9.6 nm and a nano-Scanning Mobility Particle Sizer (nSMPS and deployed along the west coast of Ireland, in the vicinity of Mace Head. The objective of the exercise was to provide high resolution micro-physical measurements of the coastal nucleation mode in order to map the spatial extent of new particle production regions and to evaluate the evolution, and associated growth rates of the coastal nucleation-mode aerosol plume. Results indicate that coastal new particle production is occurring over most areas along the land-sea interface with peak concentrations at the coastal plume-head in excess of 106 cm−3. Pseudo-Lagrangian studies of the coastal plume evolution illustrated significant growth of new particles to sizes in excess of 8 nm approximately 10 km downwind of the source region. Close to the plume head (<1 km growth rates can be as high as 123–171 nm h−1, decreasing gradually to 53–72 nm h−1 at 3 km. Further along the plume, at distances up to 10 km, the growth rates are calculated to be 17–32 nm h−1. Growth rates of this magnitude suggest that after a couple of hours, coastal nucleation mode particles can reach significant sizes where they can contribution to the regional aerosol loading.

  19. Lung deposition predictions of airborne particles and the emergence of contemporary diseases Part-I

    Directory of Open Access Journals (Sweden)

    Khan A

    2011-05-01

    Full Text Available Inhaled particles can cause a variety of pulmonary illnesses such as asthma, bronchitis, chronic obstructive pulmonary diseases (COPD and even secondary organismic diseases. Thus, predictions of inhaled aerosol deposition in the respiratory tract are essential not only to assess their possible consequences but also to optimize drug delivery using pharmaceutical aerosols. Deposition of inhaled aerosols is a complex phenomenon that depends on the physico-chemical properties of the particles, lung anatomy, and respiratory patterns of the subject. Hence, the prediction of particle deposition for an individual person poses real challenges. Different conceptual particle deposition models are employed for the estimation of deposition fraction in different region of the lung. However, these deposition fractions vary with the above mentioned parameters in addition to the modeling and computational technique. Part-I of this review article briefly describes the deposition behaviour of inhaled particulate matter and the currently available approaches for the prediction of aerosol deposition in the respiratory tract. Part-II continues this thread and provides a broad view of the health-related issues of particle exposure.

  20. Airborne particle sizes and sources found in indoor air. Rept. for Sep 89-Feb 90

    International Nuclear Information System (INIS)

    The paper summarizes results of a literature search into the sources, sizes, and concentrations of particles in indoor air, including the various types: plant, animal, mineral, combustion, home/personal care, and radioactive aerosols. The information, presented in a summary figure, has been gathered for use in designing test methodologies for air cleaners and other mitigation approaches and to aid in the selection of air cleaners. (NOTE: As concern about indoor air quality has grown, understanding indoor aerosols has become increasingly important so that control techniques may be implemented to reduce damaging health effects and soiling problems. Particle diameters must be known to predict dose or soiling and to determine efficient mitigation techniques.)

  1. Automated classification of single airborne particles from two-dimensional angle-resolved optical scattering (TAOS) patterns by non-linear filtering

    Science.gov (United States)

    Crosta, Giovanni Franco; Pan, Yong-Le; Aptowicz, Kevin B.; Casati, Caterina; Pinnick, Ronald G.; Chang, Richard K.; Videen, Gorden W.

    2013-12-01

    Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized airborne particles. In general, the interpretation of these patterns and the retrieval of the particle refractive index, shape or size alone, are difficult problems. By reformulating the problem in statistical learning terms, a solution is proposed herewith: rather than identifying airborne particles from their scattering patterns, TAOS patterns themselves are classified through a learning machine, where feature extraction interacts with multivariate statistical analysis. Feature extraction relies on spectrum enhancement, which includes the discrete cosine FOURIER transform and non-linear operations. Multivariate statistical analysis includes computation of the principal components and supervised training, based on the maximization of a suitable figure of merit. All algorithms have been combined together to analyze TAOS patterns, organize feature vectors, design classification experiments, carry out supervised training, assign unknown patterns to classes, and fuse information from different training and recognition experiments. The algorithms have been tested on a data set with more than 3000 TAOS patterns. The parameters that control the algorithms at different stages have been allowed to vary within suitable bounds and are optimized to some extent. Classification has been targeted at discriminating aerosolized Bacillus subtilis particles, a simulant of anthrax, from atmospheric aerosol particles and interfering particles, like diesel soot. By assuming that all training and recognition patterns come from the respective reference materials only, the most satisfactory classification result corresponds to 20% false negatives from B. subtilis particles and <11% false positives from all other aerosol particles. The most effective operations have consisted of thresholding TAOS patterns in order to reject defective ones

  2. EXPERIENCE WITH SYNCHRONOUS GENERATOR MODEL USING PARTICLE SWARM OPTIMIZATION TECHNIQUE

    OpenAIRE

    N.RATHIKA; Dr. A.SENTHIL KUMAR; A.Anusuya

    2014-01-01

    This paper intends to the modeling of polyphase synchronous generator and minimization of power losses using Particle swarm optimization (PSO) technique with a constriction factor. Usage of Polyphase synchronous generator mainly leads to the total power circulation in the system which can be distributed in all phases. Another advantage of polyphase system is the fault at one winding does not lead to the system shutdown. The Process optimization is the chastisement of adjusting a process so as...

  3. On Airborne Nano/Micro-Sized Particles Released from Low-Metallic Automotive Brakes

    Czech Academy of Sciences Publication Activity Database

    Kukutschová, J.; Moravec, Pavel; Tomášek, V.; Matějka, V.; Smolík, Jiří; Schwarz, Jaroslav; Seidlerová, J.; Šafářová, K.; Filip, P.

    2011-01-01

    Roč. 159, č. 4 (2011), s. 998-1006. ISSN 0269-7491 Institutional research plan: CEZ:AV0Z40720504 Keywords : brake wear debris * nano particles * oxidative wear Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.746, year: 2011

  4. Indoor and outdoor airborne particles. An in vitro study on mutagenic potential and toxicological implications.

    NARCIS (Netherlands)

    Houdt, van J.J.

    1988-01-01

    IntroductionAir pollution components are present as gases and as particulate matter. As particle deposition takes place in various parts of the respiratory system particulate matter may have other toxicological implications than gaseous pollutants, which all may penetrate in the low

  5. Effect of atmospheric electricity on dry deposition of airborne particles from atmosphere

    Science.gov (United States)

    Tammet, H.; Kimmel, V.; Israelsson, S.

    The electric mechanism of dry deposition is well known in the case of unattached radon daughter clusters that are unipolar charged and of high mobility. The problematic role of the electric forces in deposition of aerosol particles is theoretically examined by comparing the fluxes of particles carried by different deposition mechanisms in a model situation. The electric mechanism of deposition appears essential for particles of diameter 10-200 nm in conditions of low wind speed. The electric flux of fine particles can be dominant on the tips of leaves and needles even in a moderate atmospheric electric field of a few hundred V m -1 measured over the plane ground surface. The electric deposition is enhanced under thunderclouds and high voltage power lines. Strong wind suppresses the relative role of the electric deposition when compared with aerodynamic deposition. When compared with diffusion deposition the electric deposition appears less uniform: the precipitation particulate matter on the tips of leaves and especially on needles of top branches of conifer trees is much more intensive than on the ground surface and electrically shielded surfaces of plants. The knowledge of deposition geometry could improve our understanding of air pollution damage to plants.

  6. Aerobyologic monitoring in urban and extra urban areas : analysis of airborne fungal particle concentration; Indagini aerobiologiche in ambiente urbano ed extraurbano componente fungina aerodiffusa

    Energy Technology Data Exchange (ETDEWEB)

    Bari, A. [ENEA, Saluggia (Italy). Centro Ricerche Energia; Caramiello, R.; Fossa, V.; Potenza, A. [Turin Univ. (Italy), Dip. di Biologia Vegetale

    1995-12-01

    In the environmental monitoring studies carried out by ENEA (Italian Agency for New Technologies, Energy and the Environment) a research about air quality of Turin and Saluggia (VC) has started in collaboration with the University of Turin. This research concerns the study of pollen and airborne fungal particle concentrations in the atmosphere. In the last few years the interest in airborne spores and hyphal fragments has increased. Indeed these particles play a very important role in allergic reactions, in several other human diseases, and in plant pathology. The incidence and the risk of infections by airborne fungal spores are correlated to the general climate and to the local micro climatic conditions; a complete aerosporological knowledge can be in many cases a useful indicator for infection risks. In this study the concentrations of airborne fungal spores in two different stations (urban station, Turin; and rural station, Saluggia (VC)) has been evaluated and compared, only for the year 1992, in order to verify the influence of climatic conditions and of floristic and vegetational aspects. In order to establish the correlations between the climate and the airborne fungal data, the results of aerosporogical analysis, relative to the Turin station, are reported. This investigation cover a six year period, three of which under standard climatic conditions and three with considerable peculiarities. A comparative evaluation of the efficiency in the collection of aerobiological particles (pollen and spores) by natural traps (mosses) has been attempted in Saluggia. The results obtained by this palinological analysis have been compared with the composition of the local flora and the data monitored by a spore-trap (volumetric pollen trap) positioned on the roof of a building in the ENEA Research Center of Saluggia.

  7. Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

    Directory of Open Access Journals (Sweden)

    P. Guyon

    2005-05-01

    Full Text Available As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate 2002 campaign, we studied the emission of carbon monoxide (CO, carbon dioxide (CO2, and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN relative to CO (ERCN/CO fell in the range 14–32 cm-3 ppb-1 for most of the time, in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependant on the fire condition (combustion efficiency. Variability in the ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2, which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, indicating that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC fraction of emissions that are not sampled by the aircraft. The correction, previously unpublished for tropical deforestation fires, suggested an EF about one and a half to twice as large for these species. Vertical transport of biomass-burning plumes from the boundary layer (BL to the cloud detrainment layer (CDL and the free troposphere (FT was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non

  8. Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

    Directory of Open Access Journals (Sweden)

    P. Guyon

    2005-01-01

    Full Text Available As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate 2002 campaign, we studied the emission of carbon monoxide (CO, carbon dioxide (CO2, and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN relative to CO (ERCN/CO fell in the range 14-32 cm-3 ppb-1 in most of the investigated smoke plumes. Particle number emission ratios have to our knowledge not been previously measured in tropical deforestation fires, but our results are in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependent on the fire conditions (combustion efficiency. Variability in ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2, which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, reflecting the fact that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC fraction of emissions that are not sampled by the aircraft, which increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from the boundary layer (BL to the cloud detrainment layer (CDL and the free troposphere (FT was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol

  9. Heterogeneous reaction of N2O5 with airborne TiO2 particles and the implication for stratospheric particle injection

    Science.gov (United States)

    Tang, Mingjin; Abraham, Luke; Braesicke, Peter; Cox, Tony; McGregor, James; Pope, Francis; Pyle, John; Rkiouak, Laylla; Telford, Paul; Watson, Matt; Kalberer, Markus

    2014-05-01

    Injection of aerosol particles (or their precursors) into the stratosphere to scatter solar radiation back into space, has been suggested as a solar-radiation management (SRM) scheme for the mitigation for global warming. TiO2 has recently been highlighted as a possible candidate aerosol because of its high light scattering ability with a refractive index of 2.5 (Pope et al. 2012). The impact of particles injection on stratospheric ozone requires systematical assessment via laboratory and modelling studies. In this work, the heterogeneous reaction of airborne sub-micrometre TiO2 particles with N2O5 has been investigated at room temperature and different relative humidities (RH), using an atmospheric pressure aerosol flow tube. The uptake coefficient of N2O5 onto TiO2, γ(N2O5), was determined to be ~1.0×10-3 at low RH, and increase to ~3×10-3 at 60% RH. The dependence of γ(N2O5) on RH can be explained by the water adsorption isotherm of TiO2 particles. In addition, the uptake of N2O5 onto TiO2 aerosol particles has been included in the UKCA chemistry-climate model to assess the effect of N2O5 uptake onto TiO2 particles on the stratospheric composition. We construct a case study based on the eruption of Mt. Pinatubo, comparing the effects of TiO2 to those from the volcanic sulfate and to the situation with only background amount of aerosol. The changes in reactive nitrogen species and ozone due to the heterogeneous reaction of TiO2 with N2O5 are assessed relative to sulfate aerosol impacts. Pope, F. D., Braesicke, P., Grainger, R. G., Kalberer, M., Watson, I. M., Davidson, P. J., and Cox, R. A.: Stratospheric aerosol particles and solar-radiation management, Nature Clim. Change, 2, 713-719, 2012

  10. Particle size-dependent radical generation from wildland fire smoke

    International Nuclear Information System (INIS)

    Firefighting, along with construction, mining and agriculture, ranks among the most dangerous occupations. In addition, the work environment of firefighters is unlike that of any other occupation, not only because of the obvious physical hazards but also due to the respiratory and systemic health hazards of smoke inhalation resulting from combustion. A significant amount of research has been devoted to studying municipal firefighters; however, these studies may not be useful in wildland firefighter exposures, because the two work environments are so different. Not only are wildland firefighters exposed to different combustion products, but their exposure profiles are different. The combustion products wildland firefighters are exposed to can vary greatly in characteristics due to the type and amount of material being burned, soil conditions, temperature and exposure time. Smoke inhalation is one of the greatest concerns for firefighter health and it has been shown that the smoke consists of a large number of particles. These smoke particles contain intermediates of hydrogen, carbon and oxygen free radicals, which may pose a potential health risk. Our investigation looked into the involvement of free radicals in smoke toxicity and the relationship between particle size and radical generation. Samples were collected in discrete aerodynamic particle sizes from a wildfire in Alaska, preserved and then shipped to our laboratory for analysis. Electron spin resonance was used to measure carbon-centered as well as hydroxyl radicals produced by a Fenton-like reaction with wildfire smoke. Further study of reactive oxygen species was conducted using analysis of cellular H2O2 generation, lipid peroxidation of cellular membranes and DNA damage. Results demonstrate that coarse size-range particles contained more carbon radicals per unit mass than the ultrafine particles; however, the ultrafine particles generated more ·OH radicals in the acellular Fenton-like reaction. The

  11. The 5th Generation model of Particle Physics

    Science.gov (United States)

    Lach, Theodore

    2009-05-01

    The Standard model of Particle Physics is able to account for all known HEP phenomenon, yet it is not able to predict the masses of the quarks or leptons nor can it explain why they have their respective values. The Checker Board Model (CBM) predicts that there are 5 generation of quarks and leptons and shows a pattern to those masses, namely each three quarks or leptons (within adjacent generations or within a generation) are related to each other by a geometric mean relationship. A 2D structure of the nucleus can be imaged as 2D plate spinning on its axis, it would for all practical circumstances appear to be a 3D object. The masses of the hypothesized ``up'' and ``dn'' quarks determined by the CBM are 237.31 MeV and 42.392 MeV respectively. These new quarks in addition to a lepton of 7.4 MeV make up one of the missing generations. The details of this new particle physics model can be found at the web site: checkerboard.dnsalias.net. The only areas were this theory conflicts with existing dogma is in the value of the mass of the Top quark. The particle found at Fermi Lab must be some sort of composite particle containing Top quarks.

  12. Aggregated wind power generation probabilistic forecasting based on particle filter

    International Nuclear Information System (INIS)

    Highlights: • A new method for probabilistic forecasting of aggregated wind power generation. • A dynamic system is established based on a numerical weather prediction model. • The new method handles the non-Gaussian and time-varying wind power uncertainties. • Particle filter is applied to forecast predictive densities of wind generation. - Abstract: Probability distribution of aggregated wind power generation in a region is one of important issues for power system daily operation. This paper presents a novel method to forecast the predictive densities of the aggregated wind power generation from several geographically distributed wind farms, considering the non-Gaussian and non-stationary characteristics in wind power uncertainties. Based on a mesoscale numerical weather prediction model, a dynamic system is established to formulate the relationship between the atmospheric and near-surface wind fields of geographically distributed wind farms. A recursively backtracking framework based on the particle filter is applied to estimate the atmospheric state with the near-surface wind power generation measurements, and to forecast the possible samples of the aggregated wind power generation. The predictive densities of the aggregated wind power generation are then estimated based on these predicted samples by a kernel density estimator. In case studies, the new method presented is tested on a 9 wind farms system in Midwestern United States. The testing results that the new method can provide competitive interval forecasts for the aggregated wind power generation with conventional statistical based models, which validates the effectiveness of the new method

  13. Measurement of Soluble and Total Hexavalent Chromium in the Ambient Airborne Particles in New Jersey

    Science.gov (United States)

    Huang, Lihui; Yu, Chang Ho; Hopke, Philip K.; Lioy, Paul J.; Buckley, Brian T.; Shin, Jin Young; Fan, Zhihua (Tina)

    2015-01-01

    Hexavalent chromium (Cr(VI)) in ambient airborne particulate matter (PM) is a known pulmonary carcinogen and may have both soluble and insoluble forms. The sum of the two forms is defined as total Cr(VI). Currently, there were no methods suitable for large-scale monitoring of total Cr(VI) in ambient PM. This study developed a method to measure total Cr(VI) in ambient PM. This method includes PM collection using a Teflon filter, microwave extraction with 3% Na2CO3-2% NaOH at 95°C for 60 minutes, and Cr(VI) analysis by 1,5-diphenylcarbazide colorimetry at 540 nm. The recoveries of total Cr(VI) were 119.5 ± 10.4% and 106.3 ± 16.7% for the Cr(VI)-certified reference materials, SQC 012 and SRM 2700, respectively. Total Cr(VI) in the reference urban PM (NIST 1648a) was 26.0 ± 3.1 mg/kg (%CV = 11.9%) determined by this method. The method detection limit was 0.33 ng/m3. This method and the one previously developed to measure ambient Cr(VI), which is soluble in pH ~9.0 aqueous solution, were applied to measure Cr(VI) in ambient PM10 collected from three urban areas and one suburban area in New Jersey. The total Cr(VI) concentrations were 1.05–1.41 ng/m3 in the winter and 0.99–1.56 ng/m3 in the summer. The soluble Cr(VI) concentrations were 0.03–0.19 ng/m3 in the winter and 0.12–0.37 ng/m3 in the summer. The summer mean ratios of soluble to total Cr(VI) were 14.3–43.7%, significantly higher than 4.2–14.4% in the winter. The winter concentrations of soluble and total Cr(VI) in the suburban area were significantly lower than in the three urban areas. The results suggested that formation of Cr(VI) via atmospheric chemistry may contribute to the higher soluble Cr(VI) concentrations in the summer. PMID:26120324

  14. TOF-SIMS measurements for toxic air pollutants adsorbed on the surface of airborne particles

    Science.gov (United States)

    Tomiyasu, Bunbunoshin; Hoshi, Takahiro; Owari, Masanori; Nihei, Yoshimasa

    2003-01-01

    Three kinds of particulate matter were collected: diesel and gasoline exhaust particles emitted directly from exhaust nozzle, and suspended particulate matter (SPM) near the traffic route. Soxhlet extraction was performed on each sample. By gas-chromatograph-mass spectrometer (GC-MS) analysis of these extracts, di-ethyl phthalate and di- n-butyl phthalate were detected from the extract of SPM and diesel exhaust particles (DEPs). Because these phthalates were sometimes suspected as contamination, time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements were also performed on the samples collected at the same environment. By comparing obtained spectra, it is clear that these environmental endocrine disrupters (EEDs) were adsorbed on DEP surface. Thus, we concluded that the combination of conventional method and TOF-SIMS measurement is one of the most powerful techniques for analyzing the toxic air pollutants adsorbed on SPM surface.

  15. Phthalates in PM2.5 airborne particles in the Moravian-Silesian Region, Czech Republic

    Directory of Open Access Journals (Sweden)

    Jana Růžičková

    2016-03-01

    Full Text Available Industrial area of the Moravian-Silesian Region (the Czech Republic is highly polluted by air contaminants, especially emissions of particulate matter. Samples of PM2.5 particles were analysed by pyrolysis gas chromatography with mass spectrometric detection. Concentrations of phthalates were determined for the winter season, transitional period and the summer season. The relative concentrations of phthalates in PM2.5 particles have the same proportion in both heating and non-heating season: di(2ethylexyl phthalate > di-n-butyl phthalate > diisononyl phthalate > diethyl phthalate. The most common increase in concentration in the winter season is from 5 to 10 times higher; the maximum of average concentration was 44 times higher than in the non-heating season.

  16. Personal exposure to airborne ultrafine particles in the urban area of Milan

    International Nuclear Information System (INIS)

    The relevance of health effects related to ultrafine particles (UFPs; aerodynamic diameter 5 particles/cm3. UFPs measures were divided on the basis of crossed environments or micro-environments, days of the week and day time (hours). The highest measured mean concentrations and data variability were observed during walking time and moving on motorized vehicles (bus and car), indicating that the highest exposure to UFPs can be reached near motorized traffic. The lowest exposures were observed in green areas and in office microenvironments. An appreciable difference between working and non-working days was observed. Concentration patterns and variation by days of the week and time periods appears related to time trends in traffic intensity.

  17. Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

    OpenAIRE

    Guyon, P; Frank, G. P.; M. Welling; D. Chand; Artaxo, P.; L. Rizzo; Nishioka, G.; Kolle, O.; Fritsch, H.; Silva Dias, M. A. F.; L. V. Gatti; Cordova, A. M.; Andreae, M.O.

    2005-01-01

    As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14–32 cm-3&nbs...

  18. Non-spherical particle generation from 4D optofluidic fabrication.

    Science.gov (United States)

    Paulsen, Kevin S; Chung, Aram J

    2016-08-01

    Particles with non-spherical shapes can exhibit properties which are not available from spherical shaped particles. Complex shaped particles can provide unique benefits for areas such as drug delivery, tissue engineering, structural materials, and self-assembly building blocks. Current methods of creating complex shaped particles such as 3D printing, photolithography, and imprint lithography are limited by either slow speeds, shape limitations, or expensive processes. Previously, we presented a novel microfluidic flow lithography fabrication scheme combined with fluid inertia called optofluidic fabrication for the creation of complex shaped three-dimensional (3D) particles. This process was able to address the aforementioned limits and overcome two-dimensional shape limitations faced by traditional flow lithography methods; however, all of the created 3D particle shapes displayed top-down symmetry. Here, by introducing the time dimension into our existing optofluidic fabrication process, we break this top-down symmetry, generating fully asymmetric 3D particles where we termed the process: four-dimensional (4D) optofluidic fabrication. This 4D optofluidic fabrication is comprised of three sequential procedures. First, density mismatched precursor fluids flow past pillars within fluidic channels to manipulate the flow cross sections via fluid inertia. Next, the time dimension is incorporated by stopping the flow and allowing the denser fluids to settle by gravity to create asymmetric flow cross sections. Finally, the fluids are exposed to patterned ultraviolet (UV) light in order to polymerize fully asymmetric 3D-shaped particles. By varying inertial flow shaping, gravity-induced flow shaping, and UV light patterns, 4D optofluidic fabrication can create an infinite set of complex shaped asymmetric particles. PMID:27092661

  19. Selection of filter media used for monitoring airborne alpha-emitting particles in a radiological emergency

    International Nuclear Information System (INIS)

    We have developed on air monitor for alpha-emitting particles released to the atmosphere at an accident of nuclear reprocessing plant. Selection of a suitable filter for the monitor is considerably important in order to achieve the high-sensitive measurement of radioactive concentration. We have examined surface collection efficiencies and pressure drops for the various filters that are commercially available in Japan. It was found that the PTFE membrane filter with backing had superior performance to the others, that is, a high surface collection efficiency and low pressure drop. (author)

  20. Generation of Random Particle Packings for Discrete Element Models

    Science.gov (United States)

    Abe, S.; Weatherley, D.; Ayton, T.

    2012-04-01

    An important step in the setup process of Discrete Element Model (DEM) simulations is the generation of a suitable particle packing. There are quite a number of properties such a granular material specimen should ideally have, such as high coordination number, isotropy, the ability to fill arbitrary bounding volumes and the absence of locked-in stresses. An algorithm which is able to produce specimens fulfilling these requirements is the insertion based sphere packing algorithm originally proposed by Place and Mora, 2001 [2] and extended in this work. The algorithm works in two stages. First a number of "seed" spheres are inserted into the bounding volume. In the second stage the gaps between the "seed" spheres are filled by inserting new spheres in a way so they have D+1 (i.e. 3 in 2D, 4 in 3D) touching contacts with either other spheres or the boundaries of the enclosing volume. Here we present an implementation of the algorithm and a systematic statistical analysis of the generated sphere packings. The analysis of the particle radius distribution shows that they follow a power-law with an exponent ≈ D (i.e. ≈3 for a 3D packing and ≈2 for 2D). Although the algorithm intrinsically guarantees coordination numbers of at least 4 in 3D and 3 in 2D, the coordination numbers realized in the generated packings can be significantly higher, reaching beyond 50 if the range of particle radii is sufficiently large. Even for relatively small ranges of particle sizes (e.g. Rmin = 0.5Rmax) the maximum coordination number may exceed 10. The degree of isotropy of the generated sphere packing is also analysed in both 2D and 3D, by measuring the distribution of orientations of vectors joining the centres of adjacent particles. If the range of particle sizes is small, the packing algorithm yields moderate anisotropy approaching that expected for a face-centred cubic packing of equal-sized particles. However, once Rmin < 0.3Rmax a very high degree of isotropy is demonstrated in

  1. Concentration and particle size of airborne toxic algae (brevetoxin) derived from ocean red tide events.

    Science.gov (United States)

    Cheng, Yung Sung; McDonald, Jacob D; Kracko, Dean; Irvin, C Mitch; Zhou, Yue; Pierce, Richard H; Henry, Michael S; Bourdelaisa, Andrea; Naar, Jerome; Baden, Daniel G

    2005-05-15

    Red tides in the Gulf of Mexico are formed by blooms of the dinoflagellate Karenia brevis, which produces brevetoxins (PbTx). Brevetoxins can be transferred from water to air in the wind-powered whitecapped waves during red tide episodes. Inhalation exposure to marine aerosol containing PbTx causes respiratory problems. A liquid chromatograph/ tandem mass spectrometric method was developed for the detection and quantitation of several PbTxs in ambient samples collected during red tide events. This method was complemented by a previously developed antibody assay that analyzes the entire class of PbTx compounds. The method showed good linearity, accuracy, and reproducibility, allowing quantitation of PbTx compounds in the 10 pg/m3 range. Air concentrations of PbTxs and brevenal for individual samples ranged from 0.01 to 80 ng/m3. The particle size showed a single mode with a mass median diameter between 6 and 10 microm, which was consistent for all of the PbTx species that were measured. Our results imply that individual PbTxs were from the same marine aerosol or from marine aerosol that was produced from the same process. The particle size indicated the likelihood of high deposition efficiency in the respiratory tract with the majority of aerosol deposited in the upper airways and small but not insignificant deposition in the lower airways. PMID:15954221

  2. Rural measurements of the chemical composition of airborne particles in the Eastern United States

    International Nuclear Information System (INIS)

    Quantitative measurements of particulate composition was made at three rural sites: in central South Dakota, on the Louisiana Gulf Coastal, and in the Blue Ridge Mountains of Virginia. The first two sites were selected to determine background concentrations in continental polar and maritime tropical air masses, respectively, which affect the eastern United State during the summer. The Virginia site was selected as a receptor site, downwind of the midwestern source area. The South Dakota data established the background concentrations. These concentrations were similar to the levels in Louisiana when air parcels arrived from the Gulf of Mexico, without recently passing over the United States. Levels of fine particles (diameters less than 2.5 μm) were highest in Virginia and were due chiefly to sulfate. Using trajectory and statistical analyses, it is shown that the residence time of an air parcel over the midwestern source area was the most important variable in determining the sulface levels in the Blue Ridge Mountains

  3. Merging LANDSAT TM and airborne SAR for generating maps of Louisiana's coastal zone to facilitate oil spill cleanup

    International Nuclear Information System (INIS)

    Pollution from oil spills is an ever present risk in coastal areas. The risk increases as oil and gas exploration, extraction and transportation expands with demands for energy by a growing population and increasing standards of living. Up-to-date maps of the areas at risk will help facilitate oil spill cleanup and reduce environmental damage. In the study described here, recently acquired LANDSAT TM and airborne X-band synthetic aperture radar (SAR) were used to evaluate techniques to generate accurate and up-to-date image-based maps suitable for use by field personnel in preparation for, during and following an oil spill. Selection of the study area, selection of the LANDSAT TM data and bands, the importance of SAR data, image processing and merging techniques, selection procedures for the best image-based maps, evaluation of the merged images, and problems encountered during the study were discussed

  4. Composition and mutagenicity of PAHs associated with urban airborne particles in Córdoba, Argentina

    International Nuclear Information System (INIS)

    The comet assay and micronucleous test were used to assess the genotoxicity of organic compounds associated with particulate material collected in the city of Córdoba, Argentina. Samples were collected on fiber glass filters and their organic extracts were analyzed by GC-MS. These extracts were used for the comet assay on human lymphocytes and for the MCN test with Tradescantia pallida. The concentrations of polycyclic aromatic hydrocarbons as well as some of their nitro derivates were higher during winter. Their composition suggested that their main emission sources were gasoline and diesel vehicles. We observed genotoxic effects of these organic extracts due to the presence of both direct and indirect acting mutagens. We found a good agreement between the two test systems employed, which encourages the further use of plant bioassays for air pollution monitoring, especially in developing countries, due to their flexibility, low cost and efficiency. -- Highlights: •PAHs and nitro-PAHs were higher during winter and fall seasons. •Concentrations of PAHs were below the daily potential dose of carcinogenic PAH. •The comet assay revealed that indirect mutagens were more abundant than direct ones. •The MCN test and the comet assay demonstrated the presence of human carcinogens. -- Capsule: Indirect mutagens were more abundant during winter and fall, in agreement with the higher concentrations of PAHs and nitro-PAHs being associated with atmospheric particles

  5. Processing of airborne laser scanning data to generate accurate DTM for floodplain wetland

    Science.gov (United States)

    Szporak-Wasilewska, Sylwia; Mirosław-Świątek, Dorota; Grygoruk, Mateusz; Michałowski, Robert; Kardel, Ignacy

    2015-10-01

    Structure of the floodplain, especially its topography and vegetation, influences the overland flow and dynamics of floods which are key factors shaping ecosystems in surface water-fed wetlands. Therefore elaboration of the digital terrain model (DTM) of a high spatial accuracy is crucial in hydrodynamic flow modelling in river valleys. In this study the research was conducted in the unique Central European complex of fens and marshes - the Lower Biebrza river valley. The area is represented mainly by peat ecosystems which according to EU Water Framework Directive (WFD) are called "water-dependent ecosystems". Development of accurate DTM in these areas which are overgrown by dense wetland vegetation consisting of alder forest, willow shrubs, reed, sedges and grass is very difficult, therefore to represent terrain in high accuracy the airborne laser scanning data (ALS) with scanning density of 4 points/m2 was used and the correction of the "vegetation effect" on DTM was executed. This correction was performed utilizing remotely sensed images, topographical survey using the Real Time Kinematic positioning and vegetation height measurements. In order to classify different types of vegetation within research area the object based image analysis (OBIA) was used. OBIA allowed partitioning remotely sensed imagery into meaningful image-objects, and assessing their characteristics through spatial and spectral scale. The final maps of vegetation patches that include attributes of vegetation height and vegetation spectral properties, utilized both the laser scanning data and the vegetation indices developed on the basis of airborne and satellite imagery. This data was used in process of segmentation, attribution and classification. Several different vegetation indices were tested to distinguish different types of vegetation in wetland area. The OBIA classification allowed correction of the "vegetation effect" on DTM. The final digital terrain model was compared and examined

  6. Cosmic-Ray Generated Charged Particles for Nuclear Inspection

    International Nuclear Information System (INIS)

    Charged particles continuously rain down on the surface of the Earth. These charged particles primarily consist of muons and electrons. Muons are subatomic particles with the same charge as the electron, but with 200 times the mass. These particles are generated from interactions of primary cosmic-rays, primarily protons, with the upper atmosphere. Decision Sciences has implemented a tracking detector to measure the interactions of these particles with materials through which they pass: multiple Coulomb scattering and ionization energy loss and from these measurements is able to reconstruct a three-dimensional map of the density and atomic number of the materials in a scan volume. This map, combined with sensitive gamma detection capability of the tracking detector, enables the detection of nuclear and radiological materials that may be concealed in shielding, as well as discrimination of naturally occurring radioactive materials (NORM) from point sources that would be more associated with threats. Times to clear most non-threat cargo range from 30-60 seconds, with suspicious (heavy shielding or gamma emitting) scenes being held longer to confirm the presence of and identify nuclear or radiological materials. Extended scanning in this circumstance would typically take two to ten minutes. (author)

  7. Light absorption properties of laboratory generated tar ball particles

    Directory of Open Access Journals (Sweden)

    A. Hoffer

    2015-06-01

    Full Text Available Tar balls (TBs are a specific particle type which is abundant in the global troposphere, in particular in biomass smoke plumes. These particles belong to the family of atmospheric brown carbon (BrC which can absorb light in the visible range of the solar spectrum. Albeit TBs are typically present as individual particles in biomass smoke plumes, their absorption properties have been only indirectly inferred from field observations or calculations based on their electron energy-loss spectra. This is because in biomass smoke TBs coexist with various other particle types (e.g. organic particles with inorganic inclusions and soot, the latter is emitted mainly during flaming conditions from which they cannot be physically separated; thus, a direct experimental determination of their absorption properties is not feasible. Very recently we have demonstrated that TBs can be generated in the laboratory from droplets of wood tar that resemble atmospheric TBs in all of their observed properties. As a follow-up study we have installed on-line instruments to our laboratory set-up generating pure TB particles to measure the absorption and scattering, as well as size distribution of the particles. In addition, samples were collected for transmission electron microscopy (TEM and total carbon (TC analysis. The effects of experimental parameters were also studied. The mass absorption coefficients of the laboratory generated TBs were found to be in the range of 0.8–3.0 m2 g−1 at 550 nm, with absorption Ångström exponents (AAE between 2.7 and 3.4 (average 2.9 in the wavelength range 467–652 nm. The refractive index of TBs as derived from Mie calculations was about 1.84–0.21i at 550 nm. In the brown carbon continuum these values fall closer to those of soot than to other light-absorbing species such as humic-like substances (HULIS. Considering the abundance of TBs in biomass smoke and the global magnitude of biomass burning emissions, these findings may

  8. Light absorption properties of laboratory generated tar ball particles

    Science.gov (United States)

    Hoffer, A.; Tóth, A.; Nyirő-Kósa, I.; Pósfai, M.; Gelencsér, A.

    2015-06-01

    Tar balls (TBs) are a specific particle type which is abundant in the global troposphere, in particular in biomass smoke plumes. These particles belong to the family of atmospheric brown carbon (BrC) which can absorb light in the visible range of the solar spectrum. Albeit TBs are typically present as individual particles in biomass smoke plumes, their absorption properties have been only indirectly inferred from field observations or calculations based on their electron energy-loss spectra. This is because in biomass smoke TBs coexist with various other particle types (e.g. organic particles with inorganic inclusions and soot, the latter is emitted mainly during flaming conditions) from which they cannot be physically separated; thus, a direct experimental determination of their absorption properties is not feasible. Very recently we have demonstrated that TBs can be generated in the laboratory from droplets of wood tar that resemble atmospheric TBs in all of their observed properties. As a follow-up study we have installed on-line instruments to our laboratory set-up generating pure TB particles to measure the absorption and scattering, as well as size distribution of the particles. In addition, samples were collected for transmission electron microscopy (TEM) and total carbon (TC) analysis. The effects of experimental parameters were also studied. The mass absorption coefficients of the laboratory generated TBs were found to be in the range of 0.8-3.0 m2 g-1 at 550 nm, with absorption Ångström exponents (AAE) between 2.7 and 3.4 (average 2.9) in the wavelength range 467-652 nm. The refractive index of TBs as derived from Mie calculations was about 1.84-0.21i at 550 nm. In the brown carbon continuum these values fall closer to those of soot than to other light-absorbing species such as humic-like substances (HULIS). Considering the abundance of TBs in biomass smoke and the global magnitude of biomass burning emissions, these findings may have substantial

  9. Light absorption properties of laboratory-generated tar ball particles

    Science.gov (United States)

    Hoffer, A.; Tóth, A.; Nyirő-Kósa, I.; Pósfai, M.; Gelencsér, A.

    2016-01-01

    Tar balls (TBs) are a specific particle type that is abundant in the global troposphere, in particular in biomass smoke plumes. These particles belong to the family of atmospheric brown carbon (BrC), which can absorb light in the visible range of the solar spectrum. Albeit TBs are typically present as individual particles in biomass smoke plumes, their absorption properties have been only indirectly inferred from field observations or calculations based on their electron energy-loss spectra. This is because in biomass smoke TBs coexist with various other particle types (e.g., organic particles with inorganic inclusions and soot, the latter emitted mainly during flaming conditions) from which they cannot be physically separated; thus, a direct experimental determination of their absorption properties is not feasible. Very recently we have demonstrated that TBs can be generated in the laboratory from droplets of wood tar that resemble atmospheric TBs in all of their observed properties. As a follow-up study, we have installed on-line instruments to our laboratory set-up, which generate pure TB particles to measure the absorption and scattering, as well as the size distribution of the particles. In addition, samples were collected for transmission electron microscopy (TEM) and total carbon (TC) analysis. The effects of experimental parameters were also studied. The mass absorption coefficients of the laboratory-generated TBs were found to be in the range of 0.8-3.0 m2 g-1 at 550 nm, with absorption Ångström exponents (AAE) between 2.7 and 3.4 (average 2.9) in the wavelength range 467-652 nm. The refractive index of TBs as derived from Mie calculations was about 1.84 - 0.21i at 550 nm. In the brown carbon continuum, these values fall closer to those of soot than to other light-absorbing species such as humic-like substances (HULIS). Considering the abundance of TBs in biomass smoke and the global magnitude of biomass burning emissions, these findings may have

  10. Trace elements in airborne particles in internal industrial environments: spectrometric analysis of x-ray fluorescence (XRF)

    International Nuclear Information System (INIS)

    Fluorescence spectroscopy x-ray, is a technique of non-destructive analysis, that allows quantitative determination of the absolute concentration of chemical elements that make up a given matrix. The detected elements depend on atomic number and energy of the secondary target used for irradiation of samples. X-rays are detected and counted in a spectroscopy system based on a multichannel analyzer, that discriminates by energy and form a spectrum of independent photopeaks, whose energy identifies the element and its intensity is proportional to its concentration. The quantification requires the irradiation and counting of a set of pattern comparators, of the same elements identified in the samples. The x-ray emission shows only during the time that the selected sample is subjected to irradiation by x-ray tube. This irradiation does not change the structure nor the chemical composition of the matrix, so the sample remains unchanged, after irradiation. This condition non-destructive characterizes the fluorescence x-ray. The trace elements present in airborne particles, are determined and collected on a Nuclepore filter. The collection sites selected are: Taller de Mecanica de Precision de la Escuela de Fisica, Universidad de Costa Rica; Taller J. V. G. Precision, San Antonio de Coronado; Taller de Muflas, MUFLASA, Alto de Guadalupe; Industria Silvania S. A., Pavas. In addition, it is attached the service rendered to the enterprise Sellos Generales S. A. The working conditions and physical conditions of facilities were considered. An aerosol sampler with a temporal variation was used. Irradiation of samples and an evaluation of the concentrations have been made. (author)

  11. The impact of flood and post-flood cleaning on airborne microbiological and particle contamination in residential houses.

    Science.gov (United States)

    He, Congrong; Salonen, Heidi; Ling, Xuan; Crilley, Leigh; Jayasundara, Nadeesha; Cheung, Hing Cho; Hargreaves, Megan; Huygens, Flavia; Knibbs, Luke D; Ayoko, Godwin A; Morawska, Lidia

    2014-08-01

    In January 2011, Brisbane, Australia, experienced a major river flooding event. We aimed to investigate its effects on air quality and assess the role of prompt cleaning activities in reducing the airborne exposure risk. A comprehensive, multi-parameter indoor and outdoor measurement campaign was conducted in 41 residential houses, 2 and 6 months after the flood. The median indoor air concentrations of supermicrometer particle number (PN), PM10, fungi and bacteria 2 months after the flood were comparable to those previously measured in Brisbane. These were 2.88 p cm(-3), 15 μg m(-3), 804 cf um(-3) and 177 cf um(-3) for flood-affected houses (AFH), and 2.74 p cm(-3), 15 μg m(-3), 547 cf um(-3) and 167 cf um(-3) for non-affected houses (NFH), respectively. The I/O (indoor/outdoor) ratios of these pollutants were 1.08, 1.38, 0.74 and 1.76 for AFH and 1.03, 1.32, 0.83 and 2.17 for NFH, respectively. The average of total elements (together with transition metals) in indoor dust was 2296 ± 1328 μg m(-2) for AFH and 1454 ± 678 μg m(-2) for NFH, respectively. In general, the differences between AFH and NFH were not statistically significant, implying the absence of a measureable effect on air quality from the flood. We postulate that this was due to the very swift and effective cleaning of the flooded houses by 60,000 volunteers. Among the various cleaning methods, the use of both detergent and bleach was the most efficient at controlling indoor bacteria. All cleaning methods were equally effective for indoor fungi. This study provides quantitative evidence of the significant impact of immediate post-flood cleaning on mitigating the effects of flooding on indoor bioaerosol contamination and other pollutants. PMID:24785990

  12. Electric energy production by particle thermionic-thermoelectric power generators

    Science.gov (United States)

    Oettinger, P. E.

    1980-01-01

    Thermionic-thermoelectric power generators, composed of a thin layer of porous, low work function material separating a heated emitter electrode and a cooler collector electrode, have extremely large Seebeck coefficients of over 2 mV/K and can provide significant output power. Preliminary experiments with 20-micron thick (Ba Sr Ca)O coatings, limited by evaporative loss to temperatures below 1400 K, have yielded short circuit current densities of 500 mA/sq cm and power densities of 60 mW/ sq cm. Substantially more output is expected with cesium-coated refractory oxide particle coatings operating at higher temperatures. Practical generators will have thermal-to-electrical efficiencies of 10 to 20%. Further increases can be gained by cascading these high-temperature devices with lower temperature conventional thermoelectric generators.

  13. Recent progress on high energy particle generation at CRIEPI

    International Nuclear Information System (INIS)

    Energetic particles, such as proton and x-ray, were generated by an ultrashort-pulse laser and their characteristics were investigated. In our experimental condition (1018-1019 W/cm2, 55-400 fs), the dependencies of the maximum proton energy (Ep-max) on laser pulse duration were close to the value expected by the expansion model and Ep-max depends on not only the laser intensity but also the laser fluence. This tendency is also in good agreement with the GIST experimental results. As for a pre-pulse effect, we find it is useful for electron generation, but not good for proton acceleration. We have also demonstrated near 1 MeV protons with the laser energy of only 30 mJ by optimizing focusing spot using a deformable mirror. In addition, preliminary data of x-ray generation and x-ray imaging have been obtained. (author)

  14. Stochastic Particle Acceleration in Turbulence Generated by Magnetorotational Instability

    Science.gov (United States)

    Kimura, Shigeo S.; Toma, Kenji; Suzuki, Takeru K.; Inutsuka, Shu-ichiro

    2016-05-01

    We investigate stochastic particle acceleration in accretion flows. It is believed that magnetorotational instability (MRI) generates turbulence inside accretion flows and that cosmic rays (CRs) are accelerated by the turbulence. We calculate equations of motion for CRs in the turbulent fields generated by MRI with the shearing box approximation and without back reaction to the field. Our results show that the CRs randomly gain or lose their energy through interaction with the turbulent fields. The CRs diffuse in the configuration space anisotropically: the diffusion coefficient in the direction of the unperturbed flow is about 20 times higher than the Bohm coefficient, while those in the other directions are only a few times higher than the Bohm. The momentum distribution is isotropic and its evolution can be described by the diffusion equation in momentum space where the diffusion coefficient is a power-law function of the CR momentum. We show that the shear acceleration works efficiently for energetic particles. We also cautiously note that in the shearing box approximation, particles that cross the simulation box many times along the radial direction undergo unphysical runaway acceleration by the Lorentz transformation, which needs to be taken into account with special care.

  15. Microsparks Generated by Charged Particles in Dielectric Liquids

    Science.gov (United States)

    Geiger, Robert

    2012-10-01

    The electrodynamics of charged particles in dielectric liquids have been described by several authors [1,2]. As a charged particle approaches an electrode of opposite charge the local electric field eventually exceeds the dielectric strength of the liquid and a microspark is generated. These plasmas can be very small, about type of discharge can provide a simple means of generating non-thermal plasmas in dielectric liquids, such as oils or other hydrocarbons, which can be used to chemically process the liquids. Such a technology may lead to a highly efficient method of heavy oil upgrading which can be easily scaled. In order to understand the plasma properties optical emission spectroscopy is carried out for various hydrocarbons and voltage-current characteristics are used to determine the energy cost for this process. [4pt] [1] Melcher, James R. Continuum Electromechanics. Cambridge, MA: MIT Press, 1981.[0pt] [2] Jones, Thomas B. Electromechanics of Particles. Cambridge University Press 1995.[0pt] [3] Staack, D., Fridman, A., Gutsol, A., Gogotsi, Y. and Friedman, G. 2008, Angew. Chem., Int. Ed. 47, 8020.

  16. Heating and generation of suprathermal particles at collisionless shocks

    International Nuclear Information System (INIS)

    Collisionless plasma shocks are different from ordinary collisional fluid shocks in several important respects. They do not in general heat the electrons and ions equally, nor do they produce Maxwellian velocity distributions downstream. Furthermore, they commonly generate suprathermal particles which propagate into the upstream region, giving advance warning of the presence of the shock and providing a ''seed'' population for further acceleration to high energies. Recent space observations and theory have revealed a great deal about the heating mechanisms which occur in collisionless shocks and about the origin of the various suprathermal particle populations which are found in association with them. An overview of the present understanding of these subjects is presented herein. 83 refs., 8 figs

  17. Measurement of airborne gunshot particles in a ballistics laboratory by sector field inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Diaz, Ernesto; Sarkis, Jorge E Souza; Viebig, Sônia; Saldiva, Paulo

    2012-01-10

    The present study aimed determines lead (Pb), antimony (Sb) and barium (Ba) as the major elements present in GSR in the environmental air of the Ballistics Laboratory of the São Paulo Criminalistics Institute (I.C.-S.P.), São Paulo, SP, Brazil. Micro environmental monitors (mini samplers) were located at selected places. The PM(2.5) fraction of this airborne was collected in, previously weighted filters, and analyzed by sector field inductively coupled plasma mass spectrometer (SF-HR-ICP-MS). The higher values of the airborne lead, antimony and barium, were found at the firing range (lead (Pb): 58.9 μg/m(3); barium (Ba): 6.9 μg/m(3); antimony (Sb): 7.3 μg/m(3)). The mean value of the airborne in this room during 6 monitored days was Pb: 23.1 μg/m(3); Ba: 2.2 μg/m(3); Sb: 1.5 μg/m(3). In the water tank room, the air did not show levels above the limits of concern. In general the airborne lead changed from day to day, but the barium and antimony remained constant. Despite of that, the obtained values suggest that the workers may be exposed to airborne lead concentration that can result in an unhealthy environment and could increase the risk of chronic intoxication. PMID:21831549

  18. EXPERIENCE WITH SYNCHRONOUS GENERATOR MODEL USING PARTICLE SWARM OPTIMIZATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    N.RATHIKA

    2014-07-01

    Full Text Available This paper intends to the modeling of polyphase synchronous generator and minimization of power losses using Particle swarm optimization (PSO technique with a constriction factor. Usage of Polyphase synchronous generator mainly leads to the total power circulation in the system which can be distributed in all phases. Another advantage of polyphase system is the fault at one winding does not lead to the system shutdown. The Process optimization is the chastisement of adjusting a process so as to optimize some stipulated set of parameters without violating some constraint. Accurate value can be extracted using PSO and it can be reformulated. Modeling and simulation of the machine is executed. MATLAB/Simulink has been cast-off to implement and validate the result.

  19. Stochastic Particle Acceleration in Turbulence Generated by the Magnetorotational Instability

    CERN Document Server

    Kimura, Shigeo S; Suzuki, Takeru K; Inutsuka, Shu-ichiro

    2016-01-01

    We investigate stochastic particle acceleration in accretion flows. It is believed that the magnetorotational instability (MRI) generates turbulence inside accretion flows and that cosmic rays (CRs) are accelerated by the turbulence. We calculate equations of motion for CRs in the turbulent fields generated by MRI with the shearing box approximation without back reaction to the field. The results show that the CRs randomly gain or lose their energies through the interaction with the turbulent fields. The CRs diffuse in the configuration space anisotropically: The diffusion coefficient in direction of the unperturbed flow is about twenty times higher than the Bohm coefficient, while those in the other directions are only a few times higher than the Bohm. The momentum distribution is isotropic, and its evolution can be described by the diffusion equation in momentum space where the diffusion coefficient is a power-law function of the CR momentum. We show that the shear acceleration efficiently works for energet...

  20. Generation of Land Cover Maps through the Fusion of Aerial Images and Airborne LiDAR Data in Urban Areas

    Directory of Open Access Journals (Sweden)

    Yongmin Kim

    2016-06-01

    Full Text Available Satellite images and aerial images with high spatial resolution have improved visual interpretation capabilities. The use of high-resolution images has rapidly grown and has been extended to various fields, such as military surveillance, disaster monitoring, and cartography. However, many problems were encountered in which one object has a variety of spectral properties and different objects have similar spectral characteristics in terms of land cover. The problems are quite noticeable, especially for building objects in urban environments. In the land cover classification process, these issues directly decrease the classification accuracy by causing misclassification of single objects as well as between objects. This study proposes a method of increasing the accuracy of land cover classification by addressing the problem of misclassifying building objects through the output-level fusion of aerial images and airborne Light Detection and Ranging (LiDAR data. The new method consists of the following three steps: (1 generation of the segmented image via a process that performs adaptive dynamic range linear stretching and modified seeded region growth algorithms; (2 extraction of building information from airborne LiDAR data using a planar filter and binary supervised classification; and (3 generation of a land cover map using the output-level fusion of two results and object-based classification. The new method was tested at four experimental sites with the Min-Max method and the SSI-nDSM method followed by a visual assessment and a quantitative accuracy assessment through comparison with reference data. In the accuracy assessment, the new method exhibits various advantages, including reduced noise and more precise classification results. Additionally, the new method improved the overall accuracy by more than 5% over the comparative evaluation methods. The high and low patterns between the overall and building accuracies were similar. Thus, the new

  1. New generation detector for monitoring using remote-controlled ground-based and airborne systems

    International Nuclear Information System (INIS)

    A new generation detector for monitoring with the use of remote-controlled ground (UAG, robotic rovers) or aircraft (UAV, drones) means was developed and tested within a security project. The main characteristics of the detector and the results of field tests with the detector placed on unmanned aerial means (drones) are described. (orig.)

  2. Benefits of Sharing Information from Commercial Airborne Forward-Looking Sensors in the Next Generation Air Transportation System

    Science.gov (United States)

    Schaffner, Philip R.; Harrah, Steven; Neece, Robert T.

    2012-01-01

    The air transportation system of the future will need to support much greater traffic densities than are currently possible, while preserving or improving upon current levels of safety. Concepts are under development to support a Next Generation Air Transportation System (NextGen) that by some estimates will need to support up to three times current capacity by the year 2025. Weather and other atmospheric phenomena, such as wake vortices and volcanic ash, constitute major constraints on airspace system capacity and can present hazards to aircraft if encountered. To support safe operations in the NextGen environment advanced systems for collection and dissemination of aviation weather and environmental information will be required. The envisioned NextGen Network Enabled Weather (NNEW) infrastructure will be a critical component of the aviation weather support services, providing access to a common weather picture for all system users. By taking advantage of Network Enabled Operations (NEO) capabilities, a virtual 4-D Weather Data Cube with aviation weather information from many sources will be developed. One new source of weather observations may be airborne forward-looking sensors, such as the X-band weather radar. Future sensor systems that are the subject of current research include advanced multi-frequency and polarimetric radar, a variety of Lidar technologies, and infrared imaging spectrometers.

  3. Now You See It… Now You Don’t: Understanding Airborne Mapping LiDAR Collection and Data Product Generation for Archaeological Research in Mesoamerica

    Directory of Open Access Journals (Sweden)

    Juan Carlos Fernandez-Diaz

    2014-10-01

    Full Text Available In this paper we provide a description of airborne mapping LiDAR, also known as airborne laser scanning (ALS, technology and its workflow from mission planning to final data product generation, with a specific emphasis on archaeological research. ALS observations are highly customizable, and can be tailored to meet specific research needs. Thus it is important for an archaeologist to fully understand the options available during planning, collection and data product generation before commissioning an ALS survey, to ensure the intended research questions can be answered with the resultant data products. Also this knowledge is of great use for the researcher trying to understand the quality and limitations of existing datasets collected for other purposes. Throughout the paper we use examples from archeological ALS projects to illustrate the key concepts of importance for the archaeology researcher.

  4. Event generator analysis for singly strange particle production data

    International Nuclear Information System (INIS)

    We have used the event generator LUCIAE to analyze the data of singly strange particle production in pp, pA, and AA reactions at 200A GeV and compared them with the corresponding experimental data and theoretical results of HIJING, VENUS, and RQMD. The results indicate that for reproducing the NA35 data of AA reactions it requires a somewhat larger s quark suppression factor (s=0.3) and shorter formation time (τ=1 fm/c) of produced particles than for reproducing the experimental data of pp and pA (s=0.2 and τ=1.5 fm/c). This might be understood intuitively from the relationship between the effective string tension and the violence of collision. However, the NA36 data of the negative multiplicity dependence of Λ in S + Pb reaction at 200 A GeV could not be well reproduced by LUCIAE, VENUS, or RQMD, and the NA36 data prefers model parameters of s=0.2 and τ=1.5 fm/c especially, this seems hard to understand and needs further studies. From comparing the NA35 data of the rapidity distribution of Λ in S + Ag reactions to the corresponding results of LUCIAE one knows that the effect of varying the s quark suppression factor from 0.2 to 0.3 is smaller than the effect of rescattering with respect to strangeness production. copyright 1997 The American Physical Society

  5. 最小二乘法在尘埃粒子计数器中的应用%Application of Least Square Method in the Airborne Particle Counter

    Institute of Scientific and Technical Information of China (English)

    杨娟; 卞保民; 何幼权; 贺安之

    2001-01-01

    分析了导致尘埃粒子计数器标定过程非常复杂的原因,提出将最小二乘法用于尘埃粒子计数器标定过程中的方法,有利于提高仪器标定的一致性并降低劳动强度。文中给出了用最小二乘法对国产激光尘埃粒子计数器进行标定的实验结果。%The reasons that lead to the complication in the process of demarcating the airborne particle counter is anal-ysed in this paper. And the Least Square Method is introduced, which can increase effectively the consistency of the in-strument demarcation and decrease the labor intensity. Experimental results calculated by the Least Square Method hasbeen performed with laser airborne particle counter.

  6. Observation and Discussion of the Latest Airborne Particle Counter of Hach Company%美国哈希公司尘埃粒子计数器最新动态观察与探讨

    Institute of Scientific and Technical Information of China (English)

    刘柳; 梁毅

    2012-01-01

    以美国哈希公司生产的METONE3411便携式尘埃粒子计数器为例,介绍了目前制药工业洁净区空气悬浮粒子的控制和监测方面的最新技术动向,并探讨其应用。%This paper introduces the current pharmaceutical airborne particle control and monitoring of the latest technology trends,using MET ONE 3411 portable airborne particle counters produced by Hath Company as an example, and discussed its application.

  7. Two-color high-harmonic generation in plasmas: efficiency dependence on the generating particle properties.

    Science.gov (United States)

    Emelina, Anna S; Emelin, Mikhail Yu; Ganeev, Rashid A; Suzuki, Masayuki; Kuroda, Hiroto; Strelkov, Vasily V

    2016-06-27

    The high-order harmonic generation (HHG) in silver, gold, and zinc plasma plumes irradiated by orthogonally polarized two-color field is studied theoretically and experimentally. We find an increase of the HHG efficiency in comparison with the single-color case, which essentially depends on the plasma species and harmonic order. An increase of more than an order of magnitude is observed for silver plasma, whereas for gold and zinc it is lower; these results are reproduced in our calculations that include both propagation and microscopic response studies. We show that the widely used theoretical approach assuming the 1s ground state of the generating particle fails to reproduce the experimental results; the agreement is achieved in our theory using the actual quantum numbers of the outer electron of the generating particles. Moreover, our theoretical studies highlight the redistribution of the electronic density in the continuum wave packet as an important aspect of the HHG enhancement in the two-color orthogonally polarized fields with comparable intensities: in the single-color field the electronic trajectories with almost zero return energy are the most populated ones; in the two-color case the total field maximum can be shifted in time so that the trajectories with high return energies (in particular, the cut-off trajectory) become the most populated ones. PMID:27410560

  8. Encouragement of Enzyme Reaction Utilizing Heat Generation from Ferromagnetic Particles Subjected to an AC Magnetic Field.

    Directory of Open Access Journals (Sweden)

    Masashi Suzuki

    Full Text Available We propose a method of activating an enzyme utilizing heat generation from ferromagnetic particles under an ac magnetic field. We immobilize α-amylase on the surface of ferromagnetic particles and analyze its activity. We find that when α-amylase/ferromagnetic particle hybrids, that is, ferromagnetic particles, on which α-amylase molecules are immobilized, are subjected to an ac magnetic field, the particles generate heat and as a result, α-amylase on the particles is heated up and activated. We next prepare a solution, in which α-amylase/ferromagnetic particle hybrids and free, nonimmobilized chitinase are dispersed, and analyze their activities. We find that when the solution is subjected to an ac magnetic field, the activity of α-amylase immobilized on the particles increases, whereas that of free chitinase hardly changes; in other words, only α-amylase immobilized on the particles is selectively activated due to heat generation from the particles.

  9. The generation model of particle physics and galactic dark matter

    International Nuclear Information System (INIS)

    Galactic dark matter is matter hypothesized to account for the discrepancy of the mass of a galaxy determined from its gravitational effects, assuming the validity of Newton's law of universal gravitation, and the mass calculated from the "luminous matter", stars, gas, dust, etc. observed to be contained within the galaxy. The conclusive observation from the rotation curves of spiral galaxies that the mass discrepancy is greater, the larger the distance scales involved implies that either Newton's law of universal gravitation requires modification or considerably more mass (dark matter) is required to be present in each galaxy. Both the modification of Newton's law of gravitation and the hypothesis of the existence of considerable dark matter in a galaxy are discussed. It is shown that the Generation Model (GM) of particle physics, which leads to a modification of Newton's law of gravitation, is found to be essentially equivalent to that of Milgrom's modified Newtonian dynamics (MOND) theory, with the GM providing a physical understanding of the MOND theory. The continuing success of MOND theory in describing the extragalactic mass discrepancy problems constitutes a strong argument against the existence of undetected dark matter haloes, consisting of unknown nonbaryonic matter, surrounding spiral galaxies. (author)

  10. Vertical wind retrieved by airborne lidar and analysis of island induced gravity waves in combination with numerical models and in situ particle measurements

    Science.gov (United States)

    Chouza, Fernando; Reitebuch, Oliver; Jähn, Michael; Rahm, Stephan; Weinzierl, Bernadett

    2016-04-01

    This study presents the analysis of island induced gravity waves observed by an airborne Doppler wind lidar (DWL) during SALTRACE. First, the instrumental corrections required for the retrieval of high spatial resolution vertical wind measurements from an airborne DWL are presented and the measurement accuracy estimated by means of two different methods. The estimated systematic error is below -0.05 m s-1 for the selected case of study, while the random error lies between 0.1 and 0.16 m s-1 depending on the estimation method. Then, the presented method is applied to two measurement flights during which the presence of island induced gravity waves was detected. The first case corresponds to a research flight conducted on 17 June 2013 in the Cabo Verde islands region, while the second case corresponds to a measurement flight on 26 June 2013 in the Barbados region. The presence of trapped lee waves predicted by the calculated Scorer parameter profiles was confirmed by the lidar and in situ observations. The DWL measurements are used in combination with in situ wind and particle number density measurements, large-eddy simulations (LES), and wavelet analysis to determine the main characteristics of the observed island induced trapped waves.

  11. Nanoparticle production by UV irradiation of combustion generated soot particles

    International Nuclear Information System (INIS)

    Laser ablation of surfaces normally produce high temperature plasmas that are difficult to control. By irradiating small particles in the gas phase, we can better control the size and concentration of the resulting particles when different materials are photofragmented. Here, we irradiate soot with 193 nm light from an ArF excimer laser. Irradiating the original agglomerated particles at fluences ranging from 0.07 to 0.26 J/cm2 with repetition rates of 20 and 100 Hz produces a large number of small, unagglomerated particles, and a smaller number of spherical agglomerated particles. Mean particle diameters from 20 to 50 nm are produced from soot originally having a mean electric mobility diameter of 265 nm. We use a non-dimensional parameter, called the photon-atom ratio (PAR), to aid in understanding the photofragmentation process. This parameter is the ratio of the number of photons striking the soot particles to the number of the carbon atoms contained in the soot particles, and is a better metric than the laser fluence for analyzing laser-particle interactions. These results suggest that UV photofragmentation can be effective in controlling particle size and morphology, and can be a useful diagnostic for studying elements of the laser ablation process

  12. Nanoparticle production by UV irradiation of combustion generated soot particles

    International Nuclear Information System (INIS)

    Laser ablation of surfaces normally produce high temperature plasmas that are difficult to control. By irradiating small particles in the gas phase, we can better control the size and concentration of the resulting particles when different materials are photofragmented. Here, we irradiate soot with 193 nm light from an ArF excimer laser. Irradiating the original agglomerated particles at fluences ranging from 0.07 to 0.26 J/cm2 with repetition rates of 20 and 100 Hz produces a large number of small, unagglomerated particles, and a smaller number of spherical agglomerated particles. Mean particle diameters from 20 to 50 nm are produced from soot originally having a mean electric mobility diameter of 265nm. We use a non-dimensional parameter, called the photon/atom ratio (PAR), to aid in understanding the photofragmentation process. This parameter is the ratio of the number of photons striking the soot particles to the number of the carbon atoms contained in the soot particles, and is a better metric than the laser fluence for analyzing laser-particle interactions. These results suggest that UV photofragmentation can be effective in controlling particle size and morphology, and can be a useful diagnostic for studying elements of the laser ablation process

  13. Generation of high-energy particles, neutrino and fotons in magnetosphere of collapsing star

    Directory of Open Access Journals (Sweden)

    Kryvdyk Volodymyr

    2014-04-01

    Full Text Available The generation of particles, photons and neutrinos in magnetosphere of collapsing star are considered. These processes are caused the self-interaction initial accelerating in magnetosphere protons and electrons. The second particles and photons will arise as a result of this self-interaction, which in turn will generate charged particles, photons and neutrino (cascade process. These processes are especially effective for the formation collapsing star magnetosphere from the secondary charged particles. In addition, the particles, photons and neutrinos will be generated in magnetosphere of collapsing star as result of these processes.

  14. Collisionless Shocks -- Magnetic Field Generation and Particle Acceleration

    OpenAIRE

    Frederiksen, J. Trier; Hededal, C. B.; Haugboelle, T.; Nordlund, A.

    2003-01-01

    We present numerical results from plasma particle simulations of collisionless shocks and ultra-relativistic counter-streaming plasmas. We demonstrate how the field-particle interactions lead to particle acceleration behind the shock-front. Further, we demonstrate how ultra relativistic counter-streaming plasmas create large scale patchy magnetic field structures and that these field structures propagate down-stream of the shock front. These results may help explain the origin of the magnetic...

  15. Airborne exposures to PAH and PM2.5 particles for road paving workers applying conventional asphalt and crumb rubber modified asphalt.

    Science.gov (United States)

    Watts, R R; Wallingford, K M; Williams, R W; House, D E; Lewtas, J

    1998-01-01

    Personal exposure monitoring was conducted for road paving workers in three states. A research objective was to characterize and compare occupational exposures to fine respirable particles (asphalt and asphalt containing crumb rubber from shredded tires. Workers not exposed to asphalt fume were also included for comparison (to support the biomarker component of this study). The rubber content of the crumb rubber modified (CRM) asphalt at the three study sites was 12, 15, and 20%. A comparison of some specific job categories from two sites indicates greater potential carcinogenic PAH exposures during CRM asphalt work, however, the site with the greatest overall exposures did not indicate any differences for specific jobs. A statistical analysis of means for fine particle, pyrene and total carcinogenic PAH personal exposure shows, with two exceptions, there were no differences in exposures for these three measurement variables. One site shows significantly elevated pyrene exposure for CRM asphalt workers and another site similarly shows greater carcinogenic PAH exposure for CRM asphalt workers. Conventional and CRM asphalt worker airborne exposures to the PAH carcinogen marker, BaP, were very low with concentrations comparable to ambient air in many cities. However, this study demonstrates that asphalt road paving workers are exposed to elevated airborne concentrations of a group of unknown compounds that likely consist of the carcinogenic PAHs benz(a)anthracene, chrysene and methylated derivatives of both. The research described in this article has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. PMID:9577752

  16. A geomorphologist's dream come true: synoptic high resolution river bathymetry with the latest generation of airborne dual wavelength lidar

    Science.gov (United States)

    Lague, Dimitri; Launeau, Patrick; Michon, Cyril; Gouraud, Emmanuel; Juge, Cyril; Gentile, William; Hubert-Moy, Laurence; Crave, Alain

    2016-04-01

    Airborne, terrestrial lidar and Structure From Motion have dramatically changed our approach of geomorphology, from low density/precision data, to a wealth of data with a precision adequate to actually measure topographic change across multiple scales, and its relation to vegetation. Yet, an important limitation in the context of fluvial geomorphology has been the inability of these techniques to penetrate water due to the use of NIR laser wavelengths or to the complexity of accounting for water refraction in SFM. Coastal bathymetric systems using a green lidar can penetrate clear water up to 50 m but have a resolution too coarse and deployment costs that are prohibitive for fluvial research and management. After early prototypes of narrow aperture green lidar (e.g., EEARL NASA), major lidar manufacturer are now releasing dual wavelength laser system that offer water penetration consistent with shallow fluvial bathymetry at very high resolution (> 10 pts/m²) and deployment costs that makes the technology, finally accessible. This offers unique opportunities to obtain synoptic high resolution, high precision data for academic research as well as for fluvial environment management (flood risk mapping, navigability,…). In this presentation, we report on the deployment of the latest generation Teledyne-Optech Titan dual-wavelength lidar (1064 nm + 532 nm) owned by the University of Nantes and Rennes. The instrument has been deployed over several fluvial and lacustrine environments in France. We present results and recommendation on how to optimize the bathymetric cover as a function of aerial and aquatic vegetation cover and the hydrology regime of the river. In the surveyed rivers, the penetration depth varies from 0.5 to 4 m with discrete echoes (i.e., onboard detection), heavily impacted by water clarity and bottom reflectance. Simple post-processing of the full waveform record allows to recover an additional 20 % depth. As for other lidar techniques, the main

  17. MCAPM: All particle method generator and collision package

    International Nuclear Information System (INIS)

    MCAPM (Monte Carlo All Particle Method) is a collection of subroutines that read the data necessary for and perform the physics involved in collisions of neutrons, protons, deuterons, helium-3, alphas, and gammas with background material. These subroutines are divided into two packages. The first package, gen2000, reads the cross sections and distributions from binary libraries that describe in-flight reactions and formats them in a form appropriate for use by the second package. Libraries are organized by incident particle type, but contain information describing the attributes of all output particles. The method of tabulating cross section data depends on the incident particle type. Neutron and charged particle cross sections are multi-group; gamma cross sections are log-log interpolated from an energy grid consistent over all target elements. The second package, bang2000, uses these data to perform the collision physics. Each Monte Carlo particle possesses a discrete energy value allowing the kinematics of collisions to be performed on a continuous energy basis. The result of the kinematics is the attributes (type, number, energy, and direction) of all the particles emerging from the collision. MCAPM is modular and has been ported to a variety of platforms

  18. A Compact Ti:Sapphire Laser With its Third Harmonic Generation (THG) for an Airborne Ozone Differential Absorption Lidar (DIAL) Transmitter

    Science.gov (United States)

    Chen, Songsheng; Storm, Mark E.; Marsh, Waverly D.; Petway, Larry B.; Edwards, William C.; Barnes, James C.

    2000-01-01

    A compact and high-pulse-energy Ti:Sapphire laser with its Third Harmonic Generation (THG) has been developed for an airborne ozone differential absorption lidar (DIAL) to study the distributions and concentrations of the ozone throughout the troposphere. The Ti:Sapphire laser, pumped by a frequency-doubled Nd:YAG laser and seeded by a single mode diode laser, is operated either at 867 nm or at 900 nm with a pulse repetition frequency of 20 Hz. High energy laser pulses (more than 110 mJ/pulse) at 867 nm or 900 nm with a desired beam quality have been achieved and utilized to generate its third harmonic at 289nm or 300nm, which are on-line and off-line wavelengths of an airborne ozone DIAL. After being experimentally compared with Beta-Barium Borate (beta - BaB2O4 or BBO) nonlinear crystals, two Lithium Triborate (LBO) crystals (5 x 5 x 20 cu mm) are selected for the Third Harmonic Generation (THG). In this paper, we report the Ti:Sapphire laser at 900 nm and its third harmonic at 300 nm. The desired high ultraviolet (UV) output pulse energy is more than 30 mJ at 300 nm and the energy conversion efficiency from 900 nm to 300 nm is 30%.

  19. Comparison of physicochemical properties between fine (PM2.5) and coarse airborne particles at cold season in Korea.

    Science.gov (United States)

    Choung, Sungwook; Oh, Jungsun; Han, Weon Shik; Chon, Chul-Min; Kwon, Youngsang; Kim, Do Yeon; Shin, Woosik

    2016-01-15

    Although it has been well-known that atmospheric aerosols affect negatively the local air quality, human health, and climate changes, the chemical and physical properties of atmospheric aerosols are not fully understood yet. This study experimentally measured the physiochemical characteristics of fine and coarse aerosol particles at the suburban area to evaluate relative contribution to environmental pollution in consecutive seasons of autumn and winter, 2014-2015, using XRD, SEM-EDX, XNI, ICP-MS, and TOF-SIMS. For these experimental works, the fine and coarse aerosols were collected by the high volume air sampler for 7 days each season. The fine particles contain approximately 10 μg m(-3) of carbonaceous aerosols consisting of 90% organic and 10% elemental carbon. The spherical-shape carbonaceous particles were observed for the coarse samples as well. Interestingly, the coarse particles in winter showed the increased frequency of carbon-rich particles with high contents of heavy metals. These results suggest that, for the cold season, the coarse particles could contribute relatively more to the conveyance of toxic contaminants compared to the fine particles in the study area. However, the fine particles showed acidic properties so that their deposition to surface may cause facilitate the increase of mobility for toxic heavy metals in soil and groundwater environments. The fine and coarse particulate matters, therefore, should be monitored separately with temporal variation to evaluate the impact of atmospheric aerosols to environmental pollution and human health. PMID:26476059

  20. Electron Production and Collective Field Generation in Intense Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J; Covo, M K

    2006-02-09

    Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase in vacuum pressure, added heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation of present experience to significantly higher beam intensities is uncertain given the present level of understanding. With coordinated LDRD projects at LLNL and LBNL, we undertook a comprehensive R&D program including experiments, theory and simulations to better understand the phenomena, establish the essential parameters, and develop mitigating mechanisms. This LDRD project laid the essential groundwork for such a program. We developed insights into the essential processes, modeled the relevant physics, and implemented these models in computational production tools that can be used for self-consistent study of the effect on ion beams. We validated the models and tools through comparison with experimental data, including data from new diagnostics that we developed as part of this work and validated on the High-Current Experiment (HCX) at LBNL. We applied these models to High-Energy Physics (HEP) and other advanced accelerators. This project was highly successful, as evidenced by the two paragraphs above, and six paragraphs following that are taken from our 2003 proposal with minor editing that mostly consisted of changing the tense. Further benchmarks of outstanding performance are: we had 13 publications with 8 of them in refereed journals, our work was recognized by the accelerator and plasma physics communities by 8 invited papers and we have 5

  1. High mass throughput particle generation using multiple nozzle spraying

    Energy Technology Data Exchange (ETDEWEB)

    Pui, David Y. H.; Chen, Da-Ren

    2015-06-09

    Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

  2. High mass throughput particle generation using multiple nozzle spraying

    Science.gov (United States)

    Pui, David Y.H.; Chen, Da-Ren

    2004-07-20

    Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

  3. Deposition of Flame-generated Al2O3 Nano-particles on a Porous Surface

    DEFF Research Database (Denmark)

    Andersen, Sune Klint; Johannessen, Jens Tue; Wedel, Stig;

    1998-01-01

    When particles of catalytic materials become less than 50 nm they start toexhibit a stronger catalytic activity compared to their bulk counterparts. Nano-particles are thus good candidates for manufacture of highly activecatalysts. Nanometer sized particles of catalytic materials may be generated...... athigh temperatures in flames. The direct deposition from gas phase on a ceramicsubstrate tube of flame-generated particles leads to a uniform, porous layer ofsmall particles, masking the coarser structure of the substrate tube. The methodlooks promising for manufacture of catalytic filters and membranes....

  4. Number concentrations of solid particles from the spinning top aerosol generator

    International Nuclear Information System (INIS)

    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)

  5. DARTAB: a program to combine airborne radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of predicted health impacts

    International Nuclear Information System (INIS)

    The DARTAB computer code combines radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of the predicted impact of radioactive airborne effluents. DARTAB is independent of the environmental transport code used to generate the environmental exposure data and the codes used to produce the dosimetric and health effects data. Therefore human dose and risk calculations need not be added to every environmental transport code. Options are included in DARTAB to permit the user to request tabulations by various topics (e.g., cancer site, exposure pathway, etc.) to facilitate characterization of the human health impacts of the effluents. The DARTAB code was written at ORNL for the US Environmental Protection Agency, Office of Radiation Programs

  6. DARTAB: a program to combine airborne radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of predicted health impacts

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.; Eckerman, K.F.; Schlatter, E.C.; Ohr, S.Y.; Chester, R.O.

    1981-08-01

    The DARTAB computer code combines radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of the predicted impact of radioactive airborne effluents. DARTAB is independent of the environmental transport code used to generate the environmental exposure data and the codes used to produce the dosimetric and health effects data. Therefore human dose and risk calculations need not be added to every environmental transport code. Options are included in DARTAB to permit the user to request tabulations by various topics (e.g., cancer site, exposure pathway, etc.) to facilitate characterization of the human health impacts of the effluents. The DARTAB code was written at ORNL for the US Environmental Protection Agency, Office of Radiation Programs.

  7. Airborne and ground-based measurements of the trace gases and particles emitted by prescribed fires in the United States

    Directory of Open Access Journals (Sweden)

    I. R. Burling

    2011-06-01

    Full Text Available We measured the emission factors for 19 trace gas species and particulate matter (PM2.5 from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous observations that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured both the emissions in the convective smoke plume from our airborne platform and the unlofted residual smoldering combustion emissions with our ground-based platform. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including high 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts of smoke that disperses at ground level. We also show that the often ignored unlofted emissions can significantly impact estimates of total emissions. Preliminary evidence suggests large emissions of monoterpenes in the residual smoldering smoke. These data should lead to an improved capacity to model the impacts of biomass burning in similar temperate ecosystems.

  8. Airborne and ground-based measurements of the trace gases and particles emitted by prescribed fires in the United States

    Directory of Open Access Journals (Sweden)

    I. R. Burling

    2011-12-01

    Full Text Available We have measured emission factors for 19 trace gas species and particulate matter (PM2.5 from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps to close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous observations that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured both the emissions in the convective smoke plume from our airborne platform and the unlofted residual smoldering combustion emissions with our ground-based platform. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including high 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts for smoke that disperses at ground level. We also show that the often ignored unlofted emissions can significantly impact estimates of total emissions. Preliminary evidence suggests large emissions of monoterpenes in the residual smoldering smoke. These data should lead to an improved capacity to model the impacts of biomass burning in similar temperate ecosystems.

  9. Airborne and ground-based measurements of the trace gases and particles emitted from prescribed fires in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Burling, Ian; Yokelson, Robert J.; Akagi, Sheryl; Urbanski, Shawn; Wold, Cyle E.; Griffith, David WT; Johnson, Timothy J.; Reardon, James; Weise, David

    2011-12-07

    We measured the emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous suggestions that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured the emissions in the convective smoke plume from our airborne platform at the same time the unlofted residual smoldering combustion emissions were measured with our ground-based platform after the flame front passed through. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including significant 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts of smoke that disperses at ground level, and we show that the normally-ignored unlofted emissions can also significantly impact estimates of total emissions. Preliminary evidence of large emissions of monoterpenes was seen in the residual smoldering spectra, but we have not yet quantified these emissions. These data should lead to an improved capacity to model the impacts of biomass burning in similar

  10. Performance of a scanning mobility particle sizer in measuring diverse types of airborne nanoparticles: Multi-walled carbon nanotubes, welding fumes, and titanium dioxide spray.

    Science.gov (United States)

    Chen, Bean T; Schwegler-Berry, Diane; Cumpston, Amy; Cumpston, Jared; Friend, Sherri; Stone, Samuel; Keane, Michael

    2016-07-01

    Direct-reading instruments have been widely used for characterizing airborne nanoparticles in inhalation toxicology and industrial hygiene studies for exposure/risk assessments. Instruments using electrical mobility sizing followed by optical counting, e.g., scanning or sequential mobility particle spectrometers (SMPS), have been considered as the "gold standard" for characterizing nanoparticles. An SMPS has the advantage of rapid response and has been widely used, but there is little information on its performance in assessing the full spectrum of nanoparticles encountered in the workplace. In this study, an SMPS was evaluated for its effectiveness in producing "monodisperse" aerosol and its adequacy in characterizing overall particle size distribution using three test aerosols, each mimicking a unique class of real-life nanoparticles: singlets of nearly spherical titanium dioxide (TiO2), agglomerates of fiber-like multi-walled carbon nanotube (MWCNT), and aggregates that constitutes welding fume (WF). These aerosols were analyzed by SMPS, cascade impactor, and by counting and sizing of discrete particles by scanning and transmission electron microscopy. The effectiveness of the SMPS to produce classified particles (fixed voltage mode) was assessed by examination of the resulting geometric standard deviation (GSD) from the impactor measurement. Results indicated that SMPS performed reasonably well for TiO2 (GSD = 1.3), but not for MWCNT and WF as evidenced by the large GSD values of 1.8 and 1.5, respectively. For overall characterization, results from SMPS (scanning voltage mode) exhibited particle-dependent discrepancies in the size distribution and total number concentration compared to those from microscopic analysis. Further investigation showed that use of a single-stage impactor at the SMPS inlet could distort the size distribution and underestimate the concentration as shown by the SMPS, whereas the presence of vapor molecules or atom clusters in some test

  11. Performance of a Scanning Mobility Particle Sizer in Measuring Diverse Types of Airborne Nanoparticles: Multi-Walled Carbon Nanotubes, Welding Fumes, and Titanium Dioxide Spray

    Science.gov (United States)

    Chen, Bean T.; Schwegler-Berry, Diane; Cumpston, Amy; Cumpston, Jared; Friend, Sherri; Stone, Samuel; Keane, Michael

    2016-01-01

    Direct-reading instruments have been widely used for characterizing airborne nanoparticles in inhalation toxicology and industrial hygiene studies for exposure/risk assessments. Instruments using electrical mobility sizing followed by optical counting, e.g., scanning or sequential mobility particle spectrometers (SMPS), have been considered as the “gold standard” for characterizing nanoparticles. An SMPS has the advantage of rapid response and has been widely used, but there is little information on its performance in assessing the full spectrum of nanoparticles encountered in the workplace. In this study, an SMPS was evaluated for its effectiveness in producing “monodisperse” aerosol and its adequacy in characterizing overall particle size distribution using three test aerosols, each mimicking a unique class of real-life nanoparticles: singlets of nearly spherical titanium dioxide (TiO2), agglomerates of fiber-like multi-walled carbon nanotube (MWCNT), and aggregates that constitutes welding fume (WF). These aerosols were analyzed by SMPS, cascade impactor, and by counting and sizing of discrete particles by scanning and transmission electron microscopy. The effectiveness of the SMPS to produce classified particles (fixed voltage mode) was assessed by examination of the resulting geometric standard deviation (GSD) from the impactor measurement. Results indicated that SMPS performed reasonably well for TiO2 (GSD = 1.3), but not for MWCNT and WF as evidenced by the large GSD values of 1.8 and 1.5, respectively. For overall characterization, results from SMPS (scanning voltage mode) exhibited particle-dependent discrepancies in the size distribution and total number concentration compared to those from microscopic analysis. Further investigation showed that use of a single-stage impactor at the SMPS inlet could distort the size distribution and underestimate the concentration as shown by the SMPS, whereas the presence of vapor molecules or atom clusters in

  12. Exposure to Airborne Particles and Volatile Organic Compounds from Polyurethane Molding, Spray Painting, Lacquering, and Gluing in a Workshop

    Directory of Open Access Journals (Sweden)

    Bjarke Mølgaard

    2015-04-01

    Full Text Available Due to the health risk related to occupational air pollution exposure, we assessed concentrations and identified sources of particles and volatile organic compounds (VOCs in a handcraft workshop producing fishing lures. The work processes in the site included polyurethane molding, spray painting, lacquering, and gluing. We measured total VOC (TVOC concentrations and particle size distributions at three locations representing the various phases of the manufacturing and assembly process. The mean working-hour TVOC concentrations in three locations studied were 41, 37, and 24 ppm according to photo-ionization detector measurements. The mean working-hour particle number concentration varied between locations from 3000 to 36,000 cm−3. Analysis of temporal and spatial variations of TVOC concentrations revealed that there were at least four substantial VOC sources: spray gluing, mold-release agent spraying, continuous evaporation from various lacquer and paint containers, and either spray painting or lacquering (probably both. The mold-release agent spray was indirectly also a major source of ultrafine particles. The workers’ exposure can be reduced by improving the local exhaust ventilation at the known sources and by increasing the ventilation rate in the area with the continuous source.

  13. Chemically generated convective transport of micron sized particles

    Science.gov (United States)

    Shklyaev, Oleg; Das, Sambeeta; Altemose, Alicia; Shum, Henry; Balazs, Anna; Sen, Ayusman

    2015-11-01

    A variety of chemical and biological applications require manipulation of micron sized objects like cells, viruses, and large molecules. Increasing the size of particles up to a micron reduces performance of techniques based on diffusive transport. Directional transport of cargo toward detecting elements reduces the delivery time and improves performance of sensing devices. We demonstrate how chemical reactions can be used to organize fluid flows carrying particles toward the assigned destinations. Convection is driven by density variations caused by a chemical reaction occurring at a catalyst or enzyme-covered target site. If the reaction causes a reduction in fluid density, as in the case of catalytic decomposition of hydrogen peroxide, then fluid and suspended cargo is drawn toward the target along the bottom surface. The intensity of the fluid flow and the time of cargo delivery are controlled by the amount of reagent in the system. After the reagent has been consumed, the fluid pump stops and particles are found aggregated on and around the enzyme-coated patch. The pumps are reusable, being reactivated upon injection of additional reagent. The developed technique can be implemented in lab-on-a-chip devices for transportation of micro-scale object immersed in solution.

  14. Oxidative stress generated damage to DNA by gastrointestinal exposure to insoluble particles

    DEFF Research Database (Denmark)

    Møller, Peter; Folkmann, J K; Danielsen, P H;

    2012-01-01

    There is growing concern that gastrointestinal exposure to particles is associated with increased risk of toxicity to internal organs and carcinogenicity. The mechanism of action is related to particle-induced oxidative stress and oxidation of DNA. Observations from animal models indicate that...... level of lipid peroxidation derived exocyclic DNA adducts in the liver, suggesting multiple pathways of oxidative stress for particle-generated damage to DNA. At equal dose, diesel exhaust particles (SRM2975) generated larger levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine in rat liver than carbon black...... to particulate matter is associated with oxidative damage to DNA and this might be associated with increased risk of cancer....

  15. Study of chemical composition and morphology of airborne particles in Chandigarh, India using EDXRF and SEM techniques.

    Science.gov (United States)

    Sharma, S G; Srinivas, M S N

    2009-03-01

    The elemental composition and morphology of aerosols, collected from March 95 to February 96 and March 96 to August 96 respectively in the city of Chandigarh, India is determined using Energy Dispersive X-ray fluorescence and scanning electron microscopic techniques. The elemental concentration levels are found to be higher by a factor of 2-7 in the spring season as compared to the rainy season. The concentration of spherical and non-spherical (i.e. elongated) aerosols is more in the spring season and is reduced drastically in the rainy season due to the prominent wash out effect of rains. More accurate particle classification and source identification is obtained when based on combination of chemical composition and particle morphology. Possible sources identified from this analysis are soil dust, Industrial activity, Agricultural and Garbage burning, Maritime aerosols and Automobile exhaust. PMID:18418721

  16. Real-time detection and characterization of individual flowing airborne biological particles: fluorescence spectra and elastic scattering measurements

    Science.gov (United States)

    Pan, Yongle; Holler, Stephen; Chang, Richard K.; Hill, Steven C.; Pinnick, Ronald G.; Niles, Stanley; Bottiger, Jerold R.; Bronk, Burt V.

    1999-11-01

    Real-time methods which is reagentless and could detect and partially characterize bioaerosols are of current interest. We present a technique for real-time measurement of UV-excited fluorescence spectra and two-dimensional angular optical scattering (TAOS) from individual flowing biological aerosol particles. The fluorescence spectra have been observed from more than 20 samples including Bacillus subtilis, Escherichia coli, Erwinia herbicola, allergens, dust, and smoke. The S/N and resolution of the spectra are sufficient for observing small lineshape differences among the same type of bioaerosol prepared under different conditions. The additional information from TAOS regarding particle size, shape, and granularity has the potential of aiding in distinguishing bacterial aerosols from other aerosols, such as diesel and cigarette smoke.

  17. Thermal fragmentation and deactivation of combustion-generated soot particles

    KAUST Repository

    Raj, Abhijeet

    2014-09-01

    The effect of thermal treatment on diesel soot and on a commercial soot in an inert environment under isothermal conditions at intermediate temperatures (400-900°C) is studied. Two important phenomena are observed in both the soot samples: soot fragmentation leading to its mass loss, and loss of soot reactivity towards O2. Several experimental techniques such as high resolution transmission electron microscopy, electron energy loss spectroscopy, thermo-gravimetric analysis with mass spectrometry, elemental analysis, Fourier transform infrared spectroscopy and X-ray diffraction have been used to identify the changes in structures, functional groups such as oxygenates and aliphatics, σ and π bonding, O/C and H/C ratios, and crystallite parameters of soot particles, introduced by heat. A decrease in the size of primary particles and an increase in the average polycyclic aromatic hydrocarbon (PAH) size was observed in soots after thermal treatment. The activation energies of soot oxidation for thermally treated soot samples were found to be higher than those for the untreated ones at most conversion levels. The cyclic or acyclic aliphatics with sp3 hybridization were present in significant amounts in all the soot samples, but their concentration decreased with thermal treatment. Interestingly, the H/C and the O/C ratios of soot particles increased after thermal treatment, and thus, they do not support the decrease in soot reactivity. The increase in the concentration of oxygenates on soot surface indicate that their desorption from soot surface in the form of CO, CO2 and other oxygenated compounds may not be significant at the temperatures (400-900°C) studied in this work. © 2014 The Combustion Institute.

  18. Mineralogical characteristics of airborne particles collected in Beijing during a severe Asian dust storm period in spring 2002

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Asian dust storm (ADS) samples were collected on March 20,2002 in Beijing,China. High-resolution field emission scanning electron microscopy with energy dispersive X-ray detector (FESEM-EDX) and X-ray diffraction (XRD) were used to study the morphology,chemical compositions,number-size dis-tributions and mineralogical compositions of ADS particles. The mineral particles were major compo-nents in the ADS samples,accounting for 94% by number. The XRD analysis indicated that the dust particles were dominated by clay (40.3%),and quartz (19.5%),followed by plagioclase (8.4%),calcite (7.5%),K-feldspar (1.5%),hematite (0.9%),pyrite (0.9%),hornblende (0.4%) and gypsum (0.3%),with a certain amount of noncrystalline materials (20.3%). Clay minerals were mainly illite/smectite mixed lay-ers (78%),followed by illite (9%),kaolinite (6%),and chlorite (7%). In addition to these main minerals,FESEM-EDX also detected some trace minerals,such as dolomite,pyrite,thenardite,as well as heavy minerals represented by rutile,ilmenite and apatite. The mineralogical compositions of the 2002-03-20 Asian dust storm and the Saharan dust plumes were similar but the clay mineralogy showed a great distinction,with the illite/smectite mixed layers being common in the Asian dust storm but illite being common in the Saharan dust plumes.

  19. Generating optimal initial conditions for smooth particle hydrodynamics (SPH) simulations

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Steven [Los Alamos National Laboratory; Rockefeller, Gabriel M [Los Alamos National Laboratory; Fryer, Christopher L [Los Alamos National Laboratory

    2008-01-01

    We present a new optimal method to set up initial conditions for Smooth Particle Hydrodynamics Simulations, which may also be of interest for N-body simulations. This new method is based on weighted Voronoi tesselations (WVTs) and can meet arbitrarily complex spatial resolution requirements. We conduct a comprehensive review of existing SPH setup methods, and outline their advantages, limitations and drawbacks. A serial version of our WVT setup method is publicly available and we give detailed instruction on how to easily implement the new method on top of an existing parallel SPH code.

  20. Vault particles: a new generation of delivery nanodevices.

    Science.gov (United States)

    Casañas, Arnau; Guerra, Pablo; Fita, Ignasi; Verdaguer, Núria

    2012-12-01

    Vault particles possess many attributes that can be exploited in nanobiotechnology, particularly in the creation of drug delivery nanodevices. These include self-assembly, 100 nm size range, a dynamic structure that may be controlled for manipulation of drug release kinetics and natural presence in humans ensuring biocompatibility. The flexibility and the adaptability of this system have been greatly enhanced by the emerging atomic-level information and improved comprehension of vault structure and dynamics. It seems likely that this information will allow their specific tailoring to the individual requirements of each drug and target tissue. These properties provide vaults with an enormous potential as a versatile delivery platform. PMID:22677067

  1. Particle-bubble aggregate stability on static bubble generated by single nozzle on flotation process

    Science.gov (United States)

    Warjito, Harinaldi, Setyantono, Manus; Siregar, Sahala D.

    2016-06-01

    There are three sub-processes on flotation. These processes are intervening liquid film into critical thickness, rupture of liquid film forming three phase contact line, and expansion three phase contact line forming aggregate stability. Aggregate stability factor contribute to determine flotation efficiency. Aggregate stability has some important factors such as reagent and particle geometry. This research focussed on to understand effect of particle geometry to aggregate stability. Experimental setup consists of 9 x 9 x26 cm flotation column made of glass, bubble generator, particle feeding system, and high speed video camera. Bubble generator made from single nozzle with 0.3 mm diameter attached to programmable syringe pump. Particle feeding system made of pipette. Particle used in this research is taken from open pit Grasberg in Timika, Papua. Particle has sub-angular geometry and its size varies from 38 to 300 µm. Bubble-particle interaction are recorded using high speed video camera. Recordings from high speed video camera analyzed using image processing software. Experiment result shows that aggregate particle-bubble and induction time depends on particle size. Small particle (38-106 µm) has long induction time and able to rupture liquid film and also forming three phase contact line. Big particle (150-300 µm) has short induction time, so it unable to attach with bubble easily. This phenomenon is caused by apparent gravity work on particle-bubble interaction. Apparent gravity worked during particle sliding on bubble surface experience increase and reached its maximum magnitude at bubble equator. After particle passed bubble equator, apparent gravity force experience decrease. In conclusion particle size from 38-300 µm can form stable aggregate if particle attached with bubble in certain condition.

  2. A new apparatus for the measurement of X-ray absorption by flame generated particles

    International Nuclear Information System (INIS)

    An apparatus is described that allows a flame, burning under vacuum, to be irradiated by an X-ray beam from a synchrotron radiation source. Initial results concerning the ionization of flame generated soot particles are described

  3. Particle dynamics in discs with turbulence generated by the vertical shear instability

    CERN Document Server

    Stoll, Moritz H R

    2016-01-01

    Among the candidates for generating turbulence in accretion discs in situations with low intrinsic ionization the vertical shear instability (VSI) has become an interesting candidate, as it relies purely on a vertical gradient in the angular velocity. Existing simulations have shown that $\\alpha$-values a few times $10^{-4}$ can be generated. The particle growth in the early planet formation phase is determined by the dynamics of dust particles. Here, we address in particular the efficiency of VSI-turbulence in concentrating particles in order to generate overdensities and low collision velocities. We perform 3D numerical hydrodynamical simulations of accretion discs around young stars that include radiative transport and irradiation from the central star. The motion of particles within a size range of a fraction of mm up to several m is followed using standard drag formula. We confirm that under realistic conditions the VSI is able to generate turbulence in full 3D protoplanetary discs. The irradiated disc s...

  4. Airborne urban particles (Milan winter-PM2.5) cause mitotic arrest and cell death: Effects on DNA, mitochondria, AhR binding and spindle organization

    International Nuclear Information System (INIS)

    Highlights: → PM2.5 induces mitotic arrest in BEAS-2B cells. → PM2.5 induces DNA damage and activates DNA damage response. → AhR regulated genes (Cyp1A1, Cyp1B1 and AhRR) are upregulated after PM exposure. → Mitotic spindle assembly is perturbed in PM exposed cells. - Abstract: Airborne particulate matter (PM) is considered to be an important contributor to lung diseases. In the present study we report that Milan winter-PM2.5 inhibited proliferation in human bronchial epithelial cells (BEAS-2B) by inducing mitotic arrest. The cell cycle arrest was followed by an increase in mitotic-apoptotic cells, mitotic slippage and finally an increase in 'classical' apoptotic cells. Exposure to winter-PM10 induced only a slight effect which may be due to the presence of PM2.5 in this fraction while pure combustion particles failed to disturb mitosis. Fewer cells expressing the mitosis marker phospho-histone H3 compared to cells with condensed chromosomes, suggest that PM2.5 induced premature mitosis. PM2.5 was internalized into the cells and often localized in laminar organelles, although particles without apparent plasma membrane covering were also seen. In PM-containing cells mitochondria and lysosomes were often damaged, and in mitotic cells fragmented chromosomes often appeared. PM2.5 induced DNA strands breaks and triggered a DNA-damage response characterized by increased phosphorylation of ATM, Chk2 and H2AX; as well as induced a marked increase in expression of the aryl hydrocarbon receptor (AhR)-regulated genes, CYP1A1, CYP1B1 and AhRR. Furthermore, some disturbance of the organization of microtubules was indicated. It is hypothesized that the induced mitotic arrest and following cell death was due to a premature chromosome condensation caused by a combination of DNA, mitochondrial and spindle damage.

  5. "EUROPART". Airborne particles in the indoor environment. A European interdisciplinary review of scientific evidence on associations between exposure to particles in buildings and health effects

    DEFF Research Database (Denmark)

    Schneider, T.; Sundell, Jan; Bischof, W.;

    2003-01-01

    The relevance of particle mass, surface area or number concentration as risk indicators for health effects in non-industrial buildings has been assessed by a European interdisciplinary group of researchers (called EUROPART) by reviewing papers identified in Medline, Toxline, and OSH. Studies...... number concentrations can be used as generally applicable risk indicators of health effects in non-industrial buildings and consequently that there is inadequate scientific evidence for establishing limit values or guidelines for particulate mass or number concentrations....

  6. Comparison Between Dust Particle Generation In CH4 or CH4/N2 Mixing RF Plasmas

    International Nuclear Information System (INIS)

    Dust particles have been spontaneously generated either in pure CH4 or in CH4/N2 r.f. plasmas. The dust particle formation results from homogeneous nucleation in the plasma and is detected by laser light scattering (Ar+, λ = 514.5 nm). The temporal and spatial behaviour of dust particles is studied. In pure methane gas, particles are trapped in well defined clouds at the plasma sheath boundaries. In a CH4/N2 mixture, the nitrogen addition leads to an expansion of the clouds. For nitrogen contents higher than 50%, the space between the electrodes is nearly completely filled with dust particles leading to plasma instabilities and a void appears in the center of the discharge. The particles are spherical with diameters in the range 0.8-2 μm. For nitrogen-rich plasmas, the particles growth is improved and leads to a rough shape with an orange-peel-type surface texture

  7. Study on Size Distributions of Airborne Particles by Aircraft Observation in Spring over Eastern Coastal Areas of China

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; LIU Hongjie; YUE Xin; LI Hong; CHEN Jianhua; TANG Dagang

    2005-01-01

    The authors studied the size distributions of particles at an altitude of 2000 m by aircraft observation over eastern costal areas of China from Zhuhai, Guangdong to Dalian, Liaoning (0.47-30 μm, 57 channels,including number concentration distribution, surface area concentration distribution and mass concentration distribution). In these cities, the average daily concentrations of PM10 are very high. They are among the most heavily polluted cities in China. The main pollution sources are anthropogenic activities such as wood, coal and oil burning. The observed size distributions show a broad spectrum and unique multi-peak characteristics, indicating no significant impacts of individual sources from urban areas. These results are far different from the distribution type at ground level. It may reflect the comprehensive effect of the regional pollution characteristics. Monitoring results over big cities could to some extent reflect their pollution characteristics.

  8. Integrated micro-optofluidic platform for real-time detection of airborne microorganisms

    Science.gov (United States)

    Choi, Jeongan; Kang, Miran; Jung, Jae Hee

    2015-11-01

    We demonstrate an integrated micro-optofluidic platform for real-time, continuous detection and quantification of airborne microorganisms. Measurements of the fluorescence and light scattering from single particles in a microfluidic channel are used to determine the total particle number concentration and the microorganism number concentration in real-time. The system performance is examined by evaluating standard particle measurements with various sample flow rates and the ratios of fluorescent to non-fluorescent particles. To apply this method to real-time detection of airborne microorganisms, airborne Escherichia coli, Bacillus subtilis, and Staphylococcus epidermidis cells were introduced into the micro-optofluidic platform via bioaerosol generation, and a liquid-type particle collection setup was used. We demonstrate successful discrimination of SYTO82-dyed fluorescent bacterial cells from other residue particles in a continuous and real-time manner. In comparison with traditional microscopy cell counting and colony culture methods, this micro-optofluidic platform is not only more accurate in terms of the detection efficiency for airborne microorganisms but it also provides additional information on the total particle number concentration.

  9. Chaotic particle swarm optimization for economic dispatch considering the generator constraints

    International Nuclear Information System (INIS)

    Chaotic particle swarm optimization (CPSO) methods are optimization approaches based on the proposed particle swarm optimization (PSO) with adaptive inertia weight factor (AIWF) and chaotic local search (CLS). In this paper, two CPSO methods based on the logistic equation and the Tent equation are presented to solve economic dispatch (ED) problems with generator constraints and applied in two power system cases. Compared with the traditional PSO method, the convergence iterative numbers of the CPSO methods are reduced, and the solutions generation costs decrease around 5 $/h in the six unit system and 24 $/h in the 15 unit system. The simulation results show that the CPSO methods have good convergence property. The generation costs of the CPSO methods are lower than those of the traditional particle swarm optimization algorithm, and hence, CPSO methods can result in great economic effect. For economic dispatch problems, the CPSO methods are more feasible and more effective alternative approaches than the traditional particle swarm optimization algorithm

  10. MSSM4G: Reviving Bino Dark Matter with Vector-like 4th Generation Particles

    CERN Document Server

    Abdullah, Mohammad

    2016-01-01

    We supplement the minimal supersymmetric standard model (MSSM) with vector-like copies of standard model particles. Such 4th generation particles can raise the Higgs boson mass to the observed value without requiring very heavy superpartners, improving naturalness and the prospects for discovering supersymmetry at the LHC. Here we show that these new particles are also motivated cosmologically: in the MSSM, pure Bino dark matter typically overcloses the Universe, but 4th generation particles open up new annihilation channels, allowing Binos to have the correct thermal relic density without resonances or co-annihilation. We show that this can be done in a sizable region of parameter space while preserving gauge coupling unification and satisfying constraints from collider, Higgs, precision electroweak, and flavor physics.

  11. Role of particle masses in the magnetic field generation driven by the parity violating interaction

    CERN Document Server

    Dvornikov, Maxim

    2016-01-01

    Recently the new model for the generation of strong large scale magnetic fields in neutron stars, driven by the parity violating interaction, was proposed. In this model, the magnetic field instability results from the modification of the chiral magnetic effect in presence of the electroweak interaction between ultrarelativistic electrons and nucleons. In the present work we study how a nonzero mass of charged particles, which are degenerate relativistic electrons and nonrelativistic protons, influences the generation of the magnetic field in frames of this approach. For this purpose we calculate the induced electric current of these charged particles, electroweakly interacting with background neutrons and an external magnetic field, exactly accounting for the particle mass. This current is calculated by two methods: using the exact solution of the Dirac equation for a charged particle in external fields and computing the polarization operator of a photon in matter composed of background neutrons. We show tha...

  12. Monitoring and evaluation techniques for airborne contamination

    Energy Technology Data Exchange (ETDEWEB)

    Xia Yihua [China Inst. of Atomic Energy, Beijing (China)

    1997-06-01

    Monitoring and evaluation of airborne contamination are of great importance for the purpose of protection of health and safety of workers in nuclear installations. Because airborne contamination is one of the key sources to cause exposure to individuals by inhalation and digestion, and to cause diffusion of contaminants in the environment. The main objectives of monitoring and evaluation of airborne contamination are: to detect promptly a loss of control of airborne material, to help identify those individuals and predict exposure levels, to assess the intake and dose commitment to the individuals, and to provide sufficient documentation of airborne radioactivity. From the viewpoint of radiation protection, the radioactive contaminants in air can be classified into the following types: airborne aerosol, gas and noble gas, and volatile gas. In this paper, the following items are described: sampling methods and techniques, measurement and evaluation, and particle size analysis. (G.K.)

  13. Comparative learning global particle swarm optimization for optimal distributed generations' output

    OpenAIRE

    JAMIAN, Jasrul Jamani; MOKHLIS, Hazlie; Mustafa, Mohd Wazir

    2014-01-01

    The appropriate output of distributed generation (DG) in a distribution network is important for maximizing the benefit of the DG installation in the network. Therefore, most researchers have concentrated on the optimization technique to compute the optimal DG value. In this paper, the comparative learning in global particle swarm optimization (CLGPSO) method is introduced. The implementation of individual cognitive and social acceleration coefficient values for each particle and a new ...

  14. Excitation of XPS spectra from nanoscaled particles by local generation of x-rays

    International Nuclear Information System (INIS)

    In preliminary work, the authors have shown that use of an aluminum substrate to support a distribution of copper particles enables their characteristic photoelectrons to be observed within the Auger electron spectrum generated by an incident electron beam. This observation raises the possibility of the use of chemical shifts and the corresponding Auger parameter to identify the chemical states present on the surface of individual submicrometer particles within a mixture. In this context, the technique has an advantage in that, unlike conventional Auger electron spectroscopy, the electron beam does not dwell on the particle but on the substrate adjacent to it. Given the importance, for both medical and toxicological reasons, of the surface composition of such particles, the authors have continued to explore the potential of this development. In this contribution, the authors show that proximal excitation of x-rays is equally successful with magnesium substrates. In some regions of the x-ray photoelectron spectrum, the much larger Auger peaks generated by the electron beam can cause inconvenient clustering of Auger and photoelectron peaks. As in conventional x-ray photoelectron spectroscopy, the ability to switch between Al and Mg sources is useful in such situations. In this context, the authors have extended the studies to iron particles where the authors show that use of Al or Mg substrates, as necessary, can make a contribution to clear identification of individual components in the Fe 2p peaks. For this development in electron spectroscopy to achieve its full potential, it is necessary to optimize the beam conditions used to generate the local x-ray to give good selectivity of a given particle. Measurements made in support of this will be given. Of greater concern is a possible problem of local heating associated with x-ray generation. The authors continue to explore this problem and report some progress in minimizing heating of the particle while maintaining

  15. UV laser irradiation of IR laser generated particles ablated from nitrobenzyl alcohol

    International Nuclear Information System (INIS)

    Particles generated by 2.94 μm pulsed IR laser ablation of liquid 3-nitrobenzyl alcohol were irradiated with a 351 nm UV laser 3.5 mm above and parallel to the sample target. The size and concentration of the ablated particles were measured with a light scattering particle sizer. The application of the UV laser resulted in a reduction in the average particle size by one-half and an increase in the total particle concentration by a factor of nine. The optimum delay between the IR and UV lasers was between 16 and 26 μs and was dependent on the fluence of the IR laser: higher fluence led to a more rapid appearance of particulate. The ejection velocity of the particle plume, as determined by the delay time corresponding to the maximum two-laser particle concentration signal, was 130 m/s at 1600 J/m2 IR laser fluence and increased to 220 m/s at 2700 J/m2. The emission of particles extended for several ms. The observations are consistent with a rapid phase change and emission of particulate, followed by an extended emission of particles ablated from the target surface.

  16. Explicit symplectic algorithms based on generating functions for charged particle dynamics

    CERN Document Server

    Zhang, Ruili; Tang, Yifa; Liu, Jian; He, Yang; Xiao, Jianyuan

    2016-01-01

    Dynamics of a charged particle in the canonical coordinates is a Hamiltonian system, and the well-known symplectic algorithm has been regarded as the de facto method for numerical integration of Hamiltonian systems due to its long-term accuracy and fidelity. For long-term simulations with high efficiency, explicit symplectic algorithms are desirable. However, it is widely accepted that explicit symplectic algorithms are only available for sum-separable Hamiltonians, and that this restriction severely limits the application of explicit symplectic algorithms to charged particle dynamics. To overcome this difficulty, we combine the familiar sum-split method and a generating function method to construct second and third order explicit symplectic algorithms for dynamics of charged particle. The generating function method is designed to generate explicit symplectic algorithms for product-separable Hamiltonian with form of $H(\\mathbf{p},\\mathbf{q})=\\mathbf{p}_{i}f(\\mathbf{q})$ or $H(\\mathbf{p},\\mathbf{q})=\\mathbf{q}...

  17. Oxidative stress and inflammation generated DNA damage by exposure to air pollution particles

    DEFF Research Database (Denmark)

    Møller, Peter; Danielsen, Pernille Høgh; Karottki, Dorina Gabriela;

    2014-01-01

    sampled at different locations (spatial variability), times (temporal variability) or particle size fraction across different experimental systems of acellular conditions, cultured cells, animals and humans. Nevertheless, there is substantial variation in the genotoxic, inflammation and oxidative stress...... potential of PM sampled at different locations or times. Small air pollution particles did not appear more hazardous than larger particles, which is consistent with the notion that constituents such as metals and organic compounds also are important determinants for PM-generated oxidative stress and...... oxidative stress and inflammation....

  18. Role of particle masses in the magnetic field generation driven by the parity violating interaction

    Science.gov (United States)

    Dvornikov, Maxim

    2016-09-01

    Recently the new model for the generation of strong large scale magnetic fields in neutron stars, driven by the parity violating interaction, was proposed. In this model, the magnetic field instability results from the modification of the chiral magnetic effect in presence of the electroweak interaction between ultrarelativistic electrons and nucleons. In the present work we study how a nonzero mass of charged particles, which are degenerate relativistic electrons and nonrelativistic protons, influences the generation of the magnetic field in frames of this approach. For this purpose we calculate the induced electric current of these charged particles, electroweakly interacting with background neutrons and an external magnetic field, exactly accounting for the particle mass. This current is calculated by two methods: using the exact solution of the Dirac equation for a charged particle in external fields and computing the polarization operator of a photon in matter composed of background neutrons. We show that the induced current is vanishing in both approaches leading to the zero contribution of massive particles to the generated magnetic field. We discuss the implication of our results for the problem of the magnetic field generation in compact stars.

  19. [Pollution characteristics of microbial aerosols generated from a municipal sewage treatment plant].

    Science.gov (United States)

    Qiu, Xiong-Hui; Li, Yan-Peng; Niu, Tie-Jun; Li, Mei-Ling; Ma, Zhi-Hui; Miao, Ying; Wang, Xiang-Jun

    2012-07-01

    To characterize the pollution characteristics of microbial aerosols emitted from municipal sewage treatment plants, microbial aerosols were sampled with an Andersen 6-stage impactor at different treatment units of a Xi'an sewage treatment plant between June 2011 and July 2011. The plate-culture and colony-counting methods were employed to determine the concentrations, particle size distributions and median diameters of the airborne bacteria, fungi and actinomycetes. The results showed that the highest concentrations of bacteria (7 866 CFU x m(-3) +/- 960 CFU x m(-3)) and actinomycetes (2 139 CFU x m(-3) +/- 227 CFU x m(-3)) were found in the sludge-dewatering house while the highest fungi concentration (2156 CFU x m(-3) +/- 119 CFU x m(-3)) in the oxidation ditch. The airborne bacteria, fungi and actinomycetes all showed a skewed distribution in particle size. The peaks of bacteria and fungi were in the size range of 2.1-3.3 microm, whereas the peak of airborne actinomycetes was between 1. 1-2.1 microm in size. In general, the order of the median diameters of different microbial aerosols generated from the sewage treatment plant was airborne bacteria > airborne fungi > airborne actinomycetes. In addition, the spatial variation characteristics of microbial aerosols showed that the larger the particle size of the microorganism, the faster the reducing rate of the aerosol concentration. The variations in the reducing rate of concentration with particle sizes can be ordered as airborne bacteria > airborne fungi > airborne actinomycetes. PMID:23002590

  20. Particle modeling of transport of α-ray generated ion clusters in air

    International Nuclear Information System (INIS)

    A particle model is developed using the test-particle Monte Carlo method to study the transport properties of α-ray generated ion clusters in a flow of air. An efficient ion-molecule collision model is proposed to simulate the collisions between ion and air molecule. The simulations are performed for a steady state of ion transport in a circular pipe. In the steady state, generation of ions is balanced with such losses of ions as absorption of the measuring sensor or pipe wall and disappearance by positive-negative ion recombination. The calculated ion current to the measuring sensor agrees well with the previous measured data. (author)

  1. Performance of a new generation RPCs for particle physics at colliders of the next generation

    CERN Document Server

    Paolozzi, L; The ATLAS collaboration

    2013-01-01

    The upgrade of present and future experiments in particle physics at high luminosity colliders will require a level one trigger of high selectivity and robustness in order to cope with the very heavy background levels. This selectivity requires detectors with very good space and time resolution operating at high rate. We present in this paper the latest developments of the RPC detectors concerning rate capability (up to 30kHz/cm2), space resolution (few hundred microns) and time resolution (few hundred pico s). We also show that this improvement required the development of a fast, low noise and large dynamics front end electronics and a better understanding of the detector physics.

  2. Airborne particulate matter PM2.5 from Mexico City affects the generation of reactive oxygen species by blood neutrophils from asthmatics: an in vitro approach

    Directory of Open Access Journals (Sweden)

    Ceballos Guillermo

    2009-06-01

    Full Text Available Abstract Background The Mexico City Metropolitan Area is densely populated, and toxic air pollutants are generated and concentrated at a higher rate because of its geographic characteristics. It is well known that exposure to particulate matter, especially to fine and ultra-fine particles, enhances the risk of cardio-respiratory diseases, especially in populations susceptible to oxidative stress. The aim of this study was to evaluate the effect of fine particles on the respiratory burst of circulating neutrophils from asthmatic patients living in Mexico City. Methods In total, 6 subjects diagnosed with mild asthma and 11 healthy volunteers were asked to participate. Neutrophils were isolated from peripheral venous blood and incubated with fine particles, and the generation of reactive oxygen species was recorded by chemiluminescence. We also measured plasma lipoperoxidation susceptibility and plasma myeloperoxidase and paraoxonase activities by spectrophotometry. Results Asthmatic patients showed significantly lower plasma paraoxonase activity, higher susceptibility to plasma lipoperoxidation and an increase in myeloperoxidase activity that differed significantly from the control group. In the presence of fine particles, neutrophils from asthmatic patients showed an increased tendency to generate reactive oxygen species after stimulation with fine particles (PM2.5. Conclusion These findings suggest that asthmatic patients have higher oxidation of plasmatic lipids due to reduced antioxidant defense. Furthermore, fine particles tended to increase the respiratory burst of blood human neutrophils from the asthmatic group. On the whole, increased myeloperoxidase activity and susceptibility to lipoperoxidation with a concomitant decrease in paraoxonase activity in asthmatic patients could favor lung infection and hence disrupt the control of asthmatic crises.

  3. Generation and accretion of electrons in complex plasmas with cylindrical particles

    International Nuclear Information System (INIS)

    This paper presents an analytical model for the physical understanding of the charging of cylindrical dust particles in an open complex plasma system. Two different mechanisms, viz., thermionic emission and photoelectric emission have been considered for the electron generation from the charged cylindrical dust particles; the corresponding expressions for the rate of emission of electrons and their mean energy have been derived. A simple approach has been adopted to derive the expression for the rate of electron accretion to the dust particle. Further a new expression for the mean energy associated with the accreted electrons due to cylindrical dust particle has been derived and presented. An interesting comparison of results obtained in the case of spherical and cylindrical dust particles has also been made. Using these expressions, a formalism has been developed for the electronic processes in an illuminated dust cloud with cylindrical particles, on the basis of charge neutrality condition and number and energy balance of electrons; the charge carried by the cylindrical dust particles, electron temperature, and electron density corresponding to a given situation have been determined. The limitation of the applicability of the theory, viz., that the mean free path of an electron for accretion by dust particles be less than the dimension of the dust cloud has been pointed out.

  4. Oxidative stress generated damage to DNA by gastrointestinal exposure to insoluble particles.

    Science.gov (United States)

    Møller, P; Folkmann, J K; Danielsen, P H; Jantzen, K; Loft, S

    2012-07-01

    There is growing concern that gastrointestinal exposure to particles is associated with increased risk of toxicity to internal organs and carcinogenicity. The mechanism of action is related to particle-induced oxidative stress and oxidation of DNA. Observations from animal models indicate that gastrointestinal exposure to single-walled carbon nanotubes (SWCNT), fullerenes C60, carbon black, titanium dioxide and diesel exhaust particles generates oxidized DNA base lesions in organs such as the bone marrow, liver and lung. Oral exposure to nanosized carbon black has also been associated with increased level of lipid peroxidation derived exocyclic DNA adducts in the liver, suggesting multiple pathways of oxidative stress for particle-generated damage to DNA. At equal dose, diesel exhaust particles (SRM2975) generated larger levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine in rat liver than carbon black (Printex 90) did, whereas exposure to fullerenes C60 and SWCNT was the least potent. This ranking of samples was also observed for oxidatively damaged DNA in cultured cells. The extent of translocation from the gut is largely unresolved. However, there is evidence indicating that gastrointestinal exposure to particulate matter is associated with oxidative damage to DNA and this might be associated with increased risk of cancer. PMID:22292440

  5. Evaluation of fluorescent particle counter in detecting airborne bacteria%荧光粒子计数器在空气细菌监测中的应用评价

    Institute of Scientific and Technical Information of China (English)

    张艳; 马筱玲; 尹美玲; 郑海洋; 顾学军; 谢少清; 荚恒敏; 张亮; 张为俊

    2014-01-01

    Objective Airborne transmission is the main approach of nosocomial infection.Closely related to the nosocomial infection rate is the air purification of hospital environment,especially the operating theatres and patients concentrated area.Routine monitoring of hospital air is the key to reduce the incidence of hospital infection.But it's quite necessary to do a bacteria culture if using traditional airborne bacterial detection method,which will take 2~3 days and delay in results.Laser-induced fluorescence spectroscopy was first used to detect airborne biological particles and non-biological particles in the mid of 1 990s.The aim of this study is to explore the ap-plication value of fluorescent particle counter in monitoring airborne bacteria.Methods The number of biological particles was dynami-cally monitored by the fluorescent particle counter in the blood collection room,and compared with the bacterial culture counts which was collected by impacting air sampler;SPSS1 3.0 software was used to calculate the correlation coefficient r between the number of bi-ological particles and airborne bacteria.Results There was a significant correlation between the number of biological particles and the number of airborne bacteria(r=0.889);the number of airborne bacteria was below 500 cfu·m-3 in non-treatment time and increased in other condition,and it didn’t meet the requirements of national hygienic standard for disinfection.Conclusions The number of bio-logical particles detected by fluorescent particle counter can be used to indicate the number of airborne bacteria,thus hopefully,the dy-namic monitoring of airborne bacteria can be achieved.%目的:空气是医院内感染传播的主要途径,医院内环境尤其是手术室及患者集中地区的空气净化程度和医院感染发生率密切相关,对医院空气进行常规监测是降低医院感染发生的关键所在。但是传统的空气细菌检测方法需要进行细菌培养,耗时2~3 d,

  6. An exact one-particle-irreducible renormalization-group generator for critical phenomena

    International Nuclear Information System (INIS)

    An exact one-particle-irreducible renormalization-group generator for critical phenomena is derived by an infinitesimal saddle-point expansion. This replaces the usual field-theoretic loop-expansion for the free energy and Green's functions with an explicit differential equation. (Auth.)

  7. Flow analysis of vortex generators on wing sections by stereoscopic particle image velocimetry measurements

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Hansen, Martin Otto Laver; Cavar, Dalibor

    2008-01-01

    Stereoscopic particle image velocimetry measurements have been executed in a low speed wind tunnel in spanwise planes in the flow past a row of vortex generators, mounted on a bump in a fashion producing counter-rotating vortices. The measurement technique is a powerful tool which provides all...

  8. Effects of energetic particles on zonal flow generation by toroidal Alfven eigenmode

    CERN Document Server

    Qiu, Zhiyong; Zonca, Fulvio

    2016-01-01

    Generation of zonal ow (ZF) by energetic particle (EP) driven toroidal Alfven eigenmode (TAE) is investigated using nonlinear gyrokinetic theory. It is found that, nonlinear resonant EP contri- bution dominates over the usual Reynolds and Maxwell stresses due to thermal plasma nonlinear response. ZF can be forced driven in the linear growth stage of TAE, with the growth rate being twice the TAE growth rate. The ZF generation mechanism is shown to be related to polarization induced by resonant EP nonlinearity. The generated ZF has both the usual meso-scale and micro- scale radial structures. Possible consequences of this forced driven ZF on the nonlinear dynamics of TAE are also discussed.

  9. A system for airborne SAR interferometry

    DEFF Research Database (Denmark)

    Madsen, Søren Nørvang; Skou, Niels; Granholm, Johan;

    1996-01-01

    Interferometric synthetic aperture radar (INSAR) systems have already demonstrated that elevation maps can be generated rapidly with single pass airborne across-track interferometry systems (XTT), and satellite repeat track interferometry (RTT) techniques have been used to map both elevation and......) the status of the airborne interferometry activities at DCRS, including the present system configuration, recent results, and some scientific applications of the system....

  10. Particle Swarm Optimization to the U-tube steam generator in the nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Wesam Zakaria, E-mail: mimi9_m@yahoo.com

    2014-12-15

    Highlights: • We establish stability mathematical model of steam generator and reactor core. • We propose a new Particle Swarm Optimization algorithm. • The algorithm can overcome premature phenomenon and has a high search precision. • Optimal weight of steam generator is 15.1% less than the original. • Sensitivity analysis and optimal design provide reference for steam generator design. - Abstract: This paper, proposed an improved Particle Swarm Optimization approach for optimize a U-tube steam generator mathematical model. The UTSG is one of the most important component related to safety of most of the pressurized water reactor. The purpose of this article is to present an approach to optimization in which every target is considered as a separate objective to be optimized. Multi-objective optimization is a powerful tool for resolving conflicting objectives in engineering design and numerous other fields. One approach to solve multi-objective optimization problems is the non-dominated sorting Particle Swarm Optimization. PSO was applied in regarding the choice of the time intervals for the periodic testing of the model of the steam generator.

  11. Particle Swarm Optimization to the U-tube steam generator in the nuclear power plant

    International Nuclear Information System (INIS)

    Highlights: • We establish stability mathematical model of steam generator and reactor core. • We propose a new Particle Swarm Optimization algorithm. • The algorithm can overcome premature phenomenon and has a high search precision. • Optimal weight of steam generator is 15.1% less than the original. • Sensitivity analysis and optimal design provide reference for steam generator design. - Abstract: This paper, proposed an improved Particle Swarm Optimization approach for optimize a U-tube steam generator mathematical model. The UTSG is one of the most important component related to safety of most of the pressurized water reactor. The purpose of this article is to present an approach to optimization in which every target is considered as a separate objective to be optimized. Multi-objective optimization is a powerful tool for resolving conflicting objectives in engineering design and numerous other fields. One approach to solve multi-objective optimization problems is the non-dominated sorting Particle Swarm Optimization. PSO was applied in regarding the choice of the time intervals for the periodic testing of the model of the steam generator

  12. An Enhanced Quantum-Behaved Particle Swarm Algorithm for Reactive Power Optimization considering Distributed Generation Penetration

    Directory of Open Access Journals (Sweden)

    Runhai Jiao

    2015-01-01

    Full Text Available This paper puts forward a novel particle swarm optimization algorithm with quantum behavior (QPSO to solve reactive power optimization in power system with distributed generation. Moreover, differential evolution (DE operators are applied to enhance the algorithm (DQPSO. This paper focuses on the minimization of active power loss, respectively, and uses QPSO and DQPSO to determine terminal voltage of generators, and ratio of transformers, switching group number of capacitors to achieve optimal reactive power flow. The proposed algorithms are validated through three IEEE standard examples. Comparing the results obtained from QPSO and DQPSO with those obtained from PSO, we find that our algorithms are more likely to get the global optimal solution and have a better convergence. What is more, DQPSO is better than QPSO. Furthermore, with the integration of distributed generation, active power loss has decreased significantly. Specifically, PV distributed generations can suppress voltage fluctuation better than PQ distributed generations.

  13. The measurement of abrasive particles velocities in the process of abrasive water jet generation

    Science.gov (United States)

    Zeleňák, Michal; Foldyna, Josef; Říha, Zdeněk

    2014-08-01

    An optimization of the design of the abrasive cutting head using the numerical simulation requires gathering as much information about processes occurring in the cutting head as possible. Detailed knowledge of velocities of abrasive particles in the process of abrasive water jet generation is vital for the verification of the numerical model. A method of measurement of abrasive particles at the exit of focusing tube using the FPIV technique was proposed and preliminary tests are described in the paper. Results of analysis of measured velocity fields are presented in the paper.

  14. Fluid-particle interaction and generation of coherent structures over permeable beds: an experimental analysis

    Science.gov (United States)

    Corvaro, Sara; Miozzi, Massimo; Postacchini, Matteo; Mancinelli, Alessandro; Brocchini, Maurizio

    2014-10-01

    We study the dynamics of the oscillatory bottom boundary layer (BBL) that develops at a porous bed under the action of propagating water waves (also known as “ventilated BBL”). In particular, experimental tests of a ventilated BBL generated over a permeable bed made of regular plastic spheres are analysed. With the purpose of characterizing typical dynamics of nearshore waves evolving over dissipative seabeds, we focus on one specific forcing condition, characterized by large nonlinearities and vorticity generation, and expect that such dynamics be qualitatively similar also for other wave regimes. Particle tracking enables an accurate definition of the hydrodynamics generated over the porous medium with specific focus on Eulerian velocity and vorticity fields and on Lagrangian particle trajectories. Nearbed velocity components are strongly influenced by the bed configuration (sphere caps) and are characterized by small-scale oscillations due to the presence of coherent structures over the interstices. Counter-rotating vortex sheets are generated and evolve during the entire wave period; their thickness grows rapidly when flow injection from the bed occurs, while it remains constant under the influence of in-bed flow suction. The evolution of near-bed particles is influenced by strain or vortex-dominated regions. When the intensity of the vortices just outside the BBL is large (generally after flow inversion), the momentum associated to the rotation of the lower layer of vortices in the BBL is comparable with that of the passive tracers, hence the particles are captured and their original trajectories are modified, jumping to a different layer. On the contrary when strain regions are dominant, particles are restricted in the same vorticity layer until sweep or ejection turbulent processes are observed and anomalous particle transport occurs from lower to higher vortex layers and vice versa. The latter occurs during the entire wave cycle, becoming the dominant

  15. NONUNIFORMITIES OF TWO-PHASE COOLANT DISTRIBUTION IN A HEAT GENERATING PARTICLES BED

    Directory of Open Access Journals (Sweden)

    V. V. Sorokin

    2015-02-01

    Full Text Available Sufficient atomic power generation safety increase may be done with microfuel adapting to reactor plants with water coolant. Microfuel particle is a millimeter size grain containing fission material core in a protecting coverage. The coverage protects fuel contact with coolant and provides isolation of fission products inside. Well thermophysical properties of microfuel bed in a direct contact with water coolant excludes fuel overheating when accidents. Microfuel use was suggested for a VVER, а direct flow reactor for superheat steam generation, a reactor with neutron spectra adjustment by the steam partial content varying in the coolant.Nonuniformities of two-phase coolant distribution in a heat generating particles bed are predicted by calculations in this text. The one is due to multiple-valuedness of pressure drop across the bed on the steam quality dependency. The nonuniformity decreases with flow rate and particle size growths absolute pressure diminishing while porosity effect is weak. The worse case is for pressure quality of order of one. Some pure steam filled pores appears parallel to steam water mixture filled pores, latter steam quality is less than the mean of the bed. Considering this regime for the direct flow reactor for superheat steam generation we predict some water drops at the exit flow. The two-phase coolant filtration with subcooled water feed is unstable to strong disturbance effects are found. Uniformity of two-phase coolant distribution is worse than for one-phase in the same radial type reactor.

  16. Study to perform preliminary experiments to evaluate particle generation and characterization techniques for zero-gravity cloud physics experiments

    Science.gov (United States)

    Katz, U.

    1982-01-01

    Methods of particle generation and characterization with regard to their applicability for experiments requiring cloud condensation nuclei (CCN) of specified properties were investigated. Since aerosol characterization is a prerequisite to assessing performance of particle generation equipment, techniques for characterizing aerosol were evaluated. Aerosol generation is discussed, and atomizer and photolytic generators including preparation of hydrosols (used with atomizers) and the evaluation of a flight version of an atomizer are studied.

  17. Generating pseudo large footprint waveforms from small footprint full-waveform airborne LiDAR data for the layered retrieval of LAI in orchards.

    Science.gov (United States)

    Li, Wang; Niu, Zheng; Li, Jing; Chen, Hanyue; Gao, Shuai; Wu, Mingquan; Li, Dong

    2016-05-01

    Leaf area index (LAI) is a key parameter for the study of biogeochemical cycles in ecosystems. Remote sensing techniques have been widely used to estimate LAIs in a wide range of vegetation types. However, limited by the sensor detection capability, considerable fewer studies investigated the layered estimation of LAIs in the vertical direction, which can significantly affect the precision evaluation of vegetation biophysical and biochemical processes. This study tried to generate a kind of pseudo large footprint waveform from the small footprint full-waveform airborne LiDAR data by an aggregation approach. The layered distribution of canopy heights and LAIs were successfully retrieved based on the large footprint waveform data in an agricultural landscape of orchards with typical multi-layer vegetation covers. The Gaussian fitting was conducted on the normalized large footprint waveforms to identify the vertical positions for different vegetation layers. Then, the gap theory was applied to retrieve the layered LAIs. Statistically significant simple linear regression models were fitted between the LiDAR-retrieved and field-observed values for the canopy heights and LAIs in different layers. Satisfactory results were obtained with a root mean square error of 0.36 m for the overstorey canopy height (R2 = 0.82), 0.29 m for the understory canopy height (R2 = 0.76), 0.28 for overstorey LAI (R2 = 0.75), 0.40 for understory LAI (R2 = 0.64), and 0.38 for total LAI (R2 = 0.69), respectively. To conclude, estimating the layered LAIs in the multi-layer agriculture orchards from the pseudo large footprint waveforms is feasible and the estimation errors are acceptable, which will provide some new ideas and methods for the quantitative remote sensing with vegetation. PMID:27137623

  18. Displacement of particles in microfluidics by laser-generated tandem bubbles

    Science.gov (United States)

    Lautz, Jaclyn; Sankin, Georgy; Yuan, Fang; Zhong, Pei

    2010-01-01

    The dynamic interaction between laser-generated tandem bubble and individual polystyrene particles of 2 and 10 μm in diameter is studied in a microfluidic channel (25 μm height) by high-speed imaging and particle image velocimetry. The asymmetric collapse of the tandem bubble produces a pair of microjets and associated long-lasting vortices that can propel a single particle to a maximum velocity of 1.4 m∕s in 30 μs after the bubble collapse with a resultant directional displacement up to 60 μm in 150 μs. This method may be useful for high-throughput cell sorting in microfluidic devices. PMID:21124726

  19. The Generation of Nonthermal Particles in the Relativistic Magnetic Reconnection of Pair Plasmas

    CERN Document Server

    Zenitani, S

    2014-01-01

    Particle acceleration in the magnetic reconnection of electron-positron plasmas is studied by using a particle-in-cell simulation. It is found that a significantly large number of nonthermal particles are generated by the inductive electric fields around an X-type neutral line when the reconnection outflow velocity, which is known to be an Alfv\\'{e}n velocity, is on the order of the speed of light. In such a relativistic reconnection regime, we also find that electrons and positrons form a power-law-like energy distribution through their drift along the reconnection electric field under the relativistic Speiser motion. A brief discussion of the relevance of these results to the current sheet structure, which has an antiparallel magnetic field in astrophysical sources of synchrotron radiation, is presented.

  20. Expert workshop traffic-caused airborne particles in urban areas; Experten-Workshop 'Verkehrsbedingte Feinstaeube in der Stadt'

    Energy Technology Data Exchange (ETDEWEB)

    Lanzendorf, Martin; Birmili, Wolfram; Franke, Patrick

    2006-07-15

    The proceedings of the expert workshop on traffic-caused airborne particulates in urban regions include the following contributions: epidemiology of ultra-fine particulates, ultra-fine particulates and their impacts in human health, environmental particulates in the urban atmosphere: properties and future requirement of measuring methods; ultra-fine particulates from traffic emissions - problems of measuring site selection for the evaluation of human exposure, modeling of PMx emissions in the context of environmental compatibility assessments and mitigation planning, traffic-caused particulates - need for action and remedial actions from the sight of the Federal environment Agency, traffic-related measures for the reduction of urban particulate exposure and their impact on the planning of air pollution prevention, strategic environmental assessment as an instrument for the airborne particulate consideration within the traffic and regional planning.

  1. Climate-Relevant Properties of Particles Generated by Traditional and Improved Wood Burning Cook Stoves

    Science.gov (United States)

    Roden, C. A.; Bond, T. C.; Conway, S.; Osorto Pinel, B.; Maccarty, N.; Still, D.

    2005-12-01

    Some 2-3 billion people in the world use biofuel as their primary energy source for domestic fuel needs. It is estimated that the combustion of biofuel generates 20% of all carbonaceous aerosols. Uncertainty about the quantity of negative (cooling) radiative forcing generated by aerosols contributes greatly to our lack of understanding of the complete climate picture. In order to facilitate measurements of poorly characterized aerosol sources at a wide range of potential sampling sites, we designed and built an Ambulatory, Real-time ANalyzer for Aerosols or ARANA. The ARANA measures the following real-time data: absorption at three wavelengths, scattering, CO concentration, and CO2 concentration. Additionally, the sampling system captures particles on filters for later analysis. The goals of this project are 1) to gain further understanding of the properties of aerosols generated from biofuels during actual cooking events, which may vary from laboratory testing 2) Determine the factors which govern the emissions from cookstoves so that we can represent these highly variable sources in emission models 3) quantitatively assess improved cookstoves, in order to improve the design and determine the lowest emission model. In Honduras during the summers of 2005 and 2004, we measured real-time emissions from four different improved cookstoves with five tests for each type of improved stove; as well as the emissions from 12 traditional Honduran cookstoves. We observed that particles produced during different combustion phases have very different optical properties. The fire startup and fuel addition phases generally produced the most aerosols, with large quantities of very dark particles having a single scatter albedo between 0.3 and 0.5. For most tests, the single scatter albedo averaged around 0.55 indicating that the primary particles are climate warming. We summarize the characteristics of the particles emitted during cooking events, examining the single scatter albedo

  2. CALIOPE airborne CO{sub 2} DIAL (CACDI) system design

    Energy Technology Data Exchange (ETDEWEB)

    Mietz, D.; Archuleta, B.; Archuleta, J. [and others

    1997-09-01

    Los Alamos National Laboratory is currently developing an airborne CO{sub 2} Differential Absorption Lidar (DIAL) system based on second generation technology demonstrated last summer at NTS. The CALIOPE Airborne CO{sub 2} DIAL (CACDI) system requirements have been compiled based on the mission objectives and SONDIAL model trade studies. Subsystem designs have been developed based on flow down from these system requirements, as well as experience gained from second generation ground tests and N-ABLE (Non-proliferation AirBorne Lidar Experiments) airborne experiments. This paper presents the CACDI mission objectives, system requirements, the current subsystem design, and provides an overview of the airborne experimental plan.

  3. Optimal risky bidding strategy for a generating company by self-organising hierarchical particle swarm optimisation

    International Nuclear Information System (INIS)

    In this paper, an optimal risky bidding strategy for a generating company (GenCo) by self-organising hierarchical particle swarm optimisation with time-varying acceleration coefficients (SPSO-TVAC) is proposed. A significant risk index based on mean-standard deviation ratio (MSR) is maximised to provide the optimal bid prices and quantities. The Monte Carlo (MC) method is employed to simulate rivals' behaviour in competitive environment. Non-convex operating cost functions of thermal generating units and minimum up/down time constraints are taken into account. The proposed bidding strategy is implemented in a multi-hourly trading in a uniform price spot market and compared to other particle swarm optimisation (PSO). Test results indicate that the proposed SPSO-TVAC approach can provide a higher MSR than the other PSO methods. It is potentially applicable to risk management of profit variation of GenCo in spot market.

  4. Optimal risky bidding strategy for a generating company by self-organising hierarchical particle swarm optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Boonchuay, Chanwit [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology (Thailand); Ongsakul, Weerakorn, E-mail: ongsakul@ait.asi [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology (Thailand)

    2011-02-15

    In this paper, an optimal risky bidding strategy for a generating company (GenCo) by self-organising hierarchical particle swarm optimisation with time-varying acceleration coefficients (SPSO-TVAC) is proposed. A significant risk index based on mean-standard deviation ratio (MSR) is maximised to provide the optimal bid prices and quantities. The Monte Carlo (MC) method is employed to simulate rivals' behaviour in competitive environment. Non-convex operating cost functions of thermal generating units and minimum up/down time constraints are taken into account. The proposed bidding strategy is implemented in a multi-hourly trading in a uniform price spot market and compared to other particle swarm optimisation (PSO). Test results indicate that the proposed SPSO-TVAC approach can provide a higher MSR than the other PSO methods. It is potentially applicable to risk management of profit variation of GenCo in spot market.

  5. Hybrid Chaotic Particle Swarm Optimization Based Gains For Deregulated Automatic Generation Control

    Directory of Open Access Journals (Sweden)

    Cheshta Jain Dr. H. K. Verma

    2011-12-01

    Full Text Available Generation control is an important objective of power system operation. In modern power system, the traditional automatic generation control (AGC is modified by incorporating the effect of bilateral contracts. This paper investigates application of chaotic particle swarm optimization (CPSO for optimized operation of restructured AGC system. To obtain optimum gains of controllers, application of adaptive inertia weight factor and constriction factors is proposed to improve performance of particle swarm optimization (PSO algorithm. It is also observed that chaos mapping using logistic map sequence increases convergence rate of traditional PSO algorithm. The hybrid method presented in this paper gives global optimum gains of controller with significant improvement in convergence rate over basic PSO algorithm. The effectiveness and efficiency of the proposed algorithm have been tested on two area restructure system.

  6. Design of a high DC voltage generator and D-T fuser based on particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Wagner L.; Campos, Tarcisio P.R., E-mail: wagnerleite@ufmg.b, E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (DEN/ UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2011-07-01

    This paper approaches a design and simulation of a high voltage Cockcroft Walton multiplier and a compact size deuteron accelerator addressed in neutron generation by d-t fusion. We proposed a circuit arrangement, which was led to simulations. The particle accelerator was computer-generated providing particle transport and electric potential analysis. As results, the simulated voltage multiplier achieved 119 kV, and the accelerator presented a deuteron beam current up to 15 mA, achieving energies in order to 100 keV. In conclusion, the simulation motivates experimental essays in order to investigate the viability of a deuteron accelerator powered by a Cockcroft-Walton source. Such d-t fusor shall produce an interesting ion beam profile, reaching energy values near the d-t fusion cross section peak. (author)

  7. An expert system for automatic mesh generation for Sn particle transport simulation in parallel environment

    International Nuclear Information System (INIS)

    An expert system for generating an effective mesh distribution for the SN particle transport simulation has been developed. This expert system consists of two main parts: 1) an algorithm for generating an effective mesh distribution in a serial environment, and 2) an algorithm for inference of an effective domain decomposition strategy for parallel computing. For the first part, the algorithm prepares an effective mesh distribution considering problem physics and the spatial differencing scheme. For the second part, the algorithm determines a parallel-performance-index (PPI), which is defined as the ratio of the granularity to the degree-of-coupling. The parallel-performance-index provides expected performance of an algorithm depending on computing environment and resources. A large index indicates a high granularity algorithm with relatively low coupling among processors. This expert system has been successfully tested within the PENTRAN (Parallel Environment Neutral-Particle Transport) code system for simulating real-life shielding problems. (authors)

  8. Electron-scale shear instabilities: magnetic field generation and particle acceleration in astrophysical jets

    CERN Document Server

    Alves, E P; Fonseca, R A; Silva, L O

    2014-01-01

    Strong shear flow regions found in astrophysical jets are shown to be important dissipation regions, where the shear flow kinetic energy is converted into electric and magnetic field energy via shear instabilities. The emergence of these self-consistent fields make shear flows significant sites for radiation emission and particle acceleration. We focus on electron-scale instabilities, namely the collisionless, unmagnetized Kelvin-Helmholtz instability (KHI) and a large-scale dc magnetic field generation mechanism on the electron scales. We show that these processes are important candidates to generate magnetic fields in the presence of strong velocity shears, which may naturally originate in energetic matter outburst of active galactic nuclei and gamma-ray bursters. We show that the KHI is robust to density jumps between shearing flows, thus operating in various scenarios with different density contrasts. Multidimensional particle-in-cell (PIC) simulations of the KHI, performed with OSIRIS, reveal the emergen...

  9. FULL PARTICLE ELECTROMAGNETIC SIMULATIONS OF ENTROPY GENERATION ACROSS A COLLISIONLESS SHOCK

    International Nuclear Information System (INIS)

    Experimental data from Cluster have shown that entropy density can be generated across Earth's bow shock. These new observations are a starting point for a more sophisticated analysis that includes computer modeling of a collisionless shock using observed shock parameters as input. In this Letter, we present the first comparison between observations and particle-in-cell simulations of such entropy generation across a collisionless shock. The ion heating at the shock is dominated by the phase mixing of reflected and directly transmitted ions, which are separated from the incident ions. The electron heating is a nearly thermal process due to the conservation of their angular momentum. For both species, we calculate the entropy density across the shock, and obtain good consistency between observations and simulations on entropy generation across the shock. We also find that the entropy generation rate is reduced as the shock Mach number decreases

  10. FULL PARTICLE ELECTROMAGNETIC SIMULATIONS OF ENTROPY GENERATION ACROSS A COLLISIONLESS SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhongwei; Liu, Ying D.; Wang, Rui; Hu, Huidong [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Parks, George K. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Wu, Pin [Department of Physics and Astronomy, University of Delaware, Newark, DE (United States); Huang, Can [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei (China); Shi, Run, E-mail: liuxying@spaceweather.ac.cn [Memorial University of Newfoundland, St. John' s (Canada)

    2014-09-20

    Experimental data from Cluster have shown that entropy density can be generated across Earth's bow shock. These new observations are a starting point for a more sophisticated analysis that includes computer modeling of a collisionless shock using observed shock parameters as input. In this Letter, we present the first comparison between observations and particle-in-cell simulations of such entropy generation across a collisionless shock. The ion heating at the shock is dominated by the phase mixing of reflected and directly transmitted ions, which are separated from the incident ions. The electron heating is a nearly thermal process due to the conservation of their angular momentum. For both species, we calculate the entropy density across the shock, and obtain good consistency between observations and simulations on entropy generation across the shock. We also find that the entropy generation rate is reduced as the shock Mach number decreases.

  11. The generation of high-power charge particle micro beams and its interaction with condensed matter

    International Nuclear Information System (INIS)

    As has been observed experimentally, the action of a picosecond laser beam on an Al-target in air gives rise to the generation and acceleration of high-power micro electron and ion beams. An original theoretical model for describing the generation and particle acceleration of such micro beams as a result of the micro channeling effect is presented. It was found that extreme states of matter, with compression in the Gbar pressure range, can be produced by such micro beams. (author). 3 figs., 12 refs

  12. Generation of four-particle GHZ states in bimodal cavity QED

    Institute of Scientific and Technical Information of China (English)

    Yang Zhen-Biao

    2007-01-01

    We propose a scheme for preparing four-particle Greenberger-Horne-Zeilinger states using two identical bimodal cavities, each supports two modes with different frequencies. This scheme is an alternative to another published work[Christopher C Gerry 1996 Phys. Rev. A 53 4591]. Comparisons between them are discussed. The fidelity and the probability of success influenced by cavity decay for the generated states are also considered.

  13. Hawking Radiation of Mass Generating Particles From Dyonic Reissner Nordstr\\"{o}m Black Hole

    OpenAIRE

    Sakalli, I.; Övgün, A.

    2016-01-01

    The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyze the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads...

  14. Optimal Distributed Generation (DG) Allocation for Losses Reduction Using Improved Particle Swarm Optimization (IPSO) Method

    OpenAIRE

    Yusran

    2013-01-01

    The optimal aloccation of Distributed Generation (DG) was most important aspect of DG connected to electrical network scheme development. The methods to determine optimal allocation of DG like SGA dan PSO had weakness. The weakness was a large possibility to be trapped in local optimum solutions. Inertia weight (w) adding to PSO algorithm was a way to overcome the weakness. The developing method knew as Improved Particle Swarm Optimization (IPSO). This research used IPSO method fo...

  15. Combustion of PTFE: The Effects of Gravity and Pigmentation on Ultrafine Particle Generation

    Science.gov (United States)

    McKinnon, J. Thomas; Srivastava, Rajiv; Todd, Paul

    1997-01-01

    Ultrafine particles generated during polymer thermodegradation are a major health hazard, owing to their unique pathway of processing in the lung. This hazard in manned spacecraft is poorly understood, because the particulate products of polymer thermodegradation are generated under low gravity conditions. Particulate generated from the degradation of PolyTetraFluoroEthylene (PTFE), insulation coating for 20 AWG copper wire (representative of spacecraft application) under intense ohmic heating were studied in terrestrial gravity and microgravity. Microgravity tests were done in a 1.2-second drop tower at the Colorado School of Mines (CSM). Thermophoretic sampling was used for particulate collection. Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) were used to examine the smoke particulates. Image software was used to calculate particle size distribution. In addition to gravity, the color of PTFE insulation has an overwhelming effect on size, shape and morphology of the particulate. Nanometer-sized primary particles were found in all cases, and aggregation and size distribution was dependent on both color and gravity; higher aggregation occurred in low gravity. Particulates from white, black, red and yellow colored PTFE insulations were studied. Elemental analysis of the particulates shows the presence of inorganic pigments.

  16. Effective identification of the three particle modes generated during pulverized coal combustion

    Institute of Scientific and Technical Information of China (English)

    YU DunXi; XU MingHou; YAO Hong; LIU XiaoWei; ZHOU Ke

    2008-01-01

    Based on the mass fraction size distribution of aluminum (AI), an improved method for effectively identifying the modes of particulate matter from pulverized coal combustion is proposed in this study. It is found that the particle size distributions of coal-derived particulate matter actually have three modes, rather than just mere two. The ultrafine mode is mainly generated through the vaporization and condensation processes. The coarse mode is primarily formed by the coalescence of molten minerals, while the newly-found central mode is attributed to the heterogeneous condensation or adsorption of vaporized species on fine residual ash particles. The detailed investigation of the mass fraction size distribution of sulfur (S) further demonstrates the rationality and effectiveness of the mass fraction size distribution of the AI in identifying three particle modes. The results show that not only can the number of particle modes be identified in the mass fraction size distributions of the AI but also can their size boundaries be more accurately defined. This method provides new insights in elucidating particle formation mechanisms and their physico-chemical characteristics.

  17. 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...

  18. Physicochemical and optical properties of combustion-generated particles from Ship Diesel Engines

    Science.gov (United States)

    Kim, H.; Jeong, S.; Jin, H. C.; Kim, J. Y.

    2015-12-01

    Shipping contributes significantly to the anthropogenic burden of particulate matter (PM), and is among the world's highest polluting combustion sources per fuel consumed. Moreover, ships are a highly concentrated source of pollutants which are emitted into clean marine environments (e.g., Artic region). Shipping utilizes heavy fuel oil (HFO) which is less distilled compared to fuels used on land and few investigations on shipping related PM properties are available. BC is one of the dominant combustion products of ship diesel engines and its chemical and microphysical properties have a significant impact on climate by influencing the amount of albedo reduction on bright surfaces such as in polar regions. We have carried out a campaign to characterize the PM emissions from medium-sized marine engines in Gunsan, Jeonbuk Institute of Automotive Technology. The properties of ship-diesel PM have characterized depending on (1) fuel sulfur content (HFO vs. ULSD) and (2) engine conditions (Running state vs. Idling state). Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX) equipped with HRTEM and Raman spectroscopy were used for physicochemical analysis. Optical properties, which are ultimately linked to the snow/ice albedo decrease impacting climate, were assessed as well. PM generated under high engine temperature conditions had typical features of soot, e.g., concentric circles comprised of closely packed graphene layers, however PM generated by the idling state at low combustion temperature was characterized by amorphous and droplet-like carbonaceous particles with no crystalline structure. Significant differences in optical properties depending on the combustion conditions were also observed. Particles from running conditions showed wavelength-independent absorbing properties, whereas the particles from idling conditions showed enhanced absorption at shorter wavelengths, which is

  19. Particle generation methods applied in large-scale experiments on aerosol behaviour and source term studies

    International Nuclear Information System (INIS)

    In aerosol research aerosols of known size, shape, and density are highly desirable because most aerosols properties depend strongly on particle size. However, such constant and reproducible generation of those aerosol particles whose size and concentration can be easily controlled, can be achieved only in laboratory-scale tests. In large scale experiments, different generation methods for various elements and compounds have been applied. This work presents, in a brief from, a review of applications of these methods used in large scale experiments on aerosol behaviour and source term. Description of generation method and generated aerosol transport conditions is followed by properties of obtained aerosol, aerosol instrumentation used, and the scheme of aerosol generation system-wherever it was available. An information concerning aerosol generation particular purposes and reference number(s) is given at the end of a particular case. These methods reviewed are: evaporation-condensation, using a furnace heating and using a plasma torch; atomization of liquid, using compressed air nebulizers, ultrasonic nebulizers and atomization of liquid suspension; and dispersion of powders. Among the projects included in this worked are: ACE, LACE, GE Experiments, EPRI Experiments, LACE-Spain. UKAEA Experiments, BNWL Experiments, ORNL Experiments, MARVIKEN, SPARTA and DEMONA. The aim chemical compounds studied are: Ba, Cs, CsOH, CsI, Ni, Cr, NaI, TeO2, UO2Al2O3, Al2SiO5, B2O3, Cd, CdO, Fe2O3, MnO, SiO2, AgO, SnO2, Te, U3O8, BaO, CsCl, CsNO3, Urania, RuO2, TiO2, Al(OH)3, BaSO4, Eu2O3 and Sn. (Author)

  20. Ion waves generated by ion loss-cone distributions or drifting particles

    International Nuclear Information System (INIS)

    Electrostatic ion waves may be generated by ion loss-cone distributions, even when cool electrons are present. Although the propagation and stability properties of these waves are well described by a dispersion relation obtained in the electrostatic approximation, they may have a significant wave magnetic field. The emissions may be resonant or non-resonant in nature, and can occur between multiples of the gyrofrequencies of the ion species in the plasma, or as broadband waves near the lower hybrid frequency. Alfven waves may also be destabilized by ion loss-cone distributions. The ratio of the electric and magnetic fields of these waves is not always equal to the Alfven speed. These theoretical considerations are favourably compared with observations by the GEOS satellites of ion loss-cone distributions and ion waves. Particles drifting along the ambient magnetic field may generate ion waves, but knowledge of the current density only is not sufficient to determine the stability of these waves. The importance of non-drifting particle distributions which may damp the waves and the destabilizing effects of drifting, low-density particle components are discussed in connection with current structures observed by the GEOS spacecraft. (Author)

  1. Chaos Cooperative Particle Swarm Optimization Based Water Level Control for Nuclear Steam Generator

    Directory of Open Access Journals (Sweden)

    Sheng Guimin

    2016-01-01

    Full Text Available The Stability of SG (Steam Generator water level plays an important role in the safety of nuclear power plants, but it is difficult to tune the parameters of water level PID controller. A proposed novel algorithm, CCPSO (chaos cooperative particle swarm optimization, is used for tuning PID controller parameters. The (chaos particle swarm optimizationCPSO algorithm has the ability to avoid falling into local minimum and the (cooperative particle swarm optimizationCPSO-Sk has fast convergence in certain functions, so CCPSO algorithm is proposed to utilize the advantages of CPSO and CPSO-Sk. Therefore, half of the particles are updated in the CPSO-Sk, and the other half are updated in the CPSO. The information exchange of the optimal solutions obtained after the end of each iteration is the performance of CPSO-Sk and CPSO collaboration.The simulation results: compared with the PID controller whose parameters are tuned by ZN method, CCPSO show smaller overshoot, better stability, and shorter adjustment time. The simulation results show that the proposed method is effective for tuning PID parameters.

  2. CFD simulation of particle entrapment of steam generator sludge collector/loose parts weir

    International Nuclear Information System (INIS)

    A computational fluid dynamics (CFD) study was performed to explore the performance and interaction of two components designed for Pressurized Water Reactor (PWR) recirculating steam generators: the sludge collector and the loose parts weir. The sludge collector is a passive device located in the upper internals region of a PWR steam generator. The sludge collector's function is to trap sludge, particulates suspended in the secondary side recirculating flow and minimize its deposition on the tube bundle, where it increases susceptibility to tube degradation. The loose parts weir is a separate passive device placed around the sludge collector, which is expected to act as a barrier to prevent any loose parts in the upper internals region from reaching the tube bundle. Loose parts in the steam generator, if not captured, can reach the tube bundle and cause tube wall damage. The loose parts weir is considered for installation in combination with the sludge collector for both new and existing steam generators. Previously, the configuration of the sludge collector was determined based on testing and analysis. Inclusion of the loose parts weir significantly alters the flow field of the sludge collector and thus its overall performance. The purpose of this investigation is to verify the performance of the sludge collector and loose parts weir. A CFD study was performed to evaluate the interaction between the sludge collector and a loose parts weir within the steam generator, which provides insight into the flow redistribution. Models were developed for the sludge collector with and without the loose parts weir using commercial CFD software. Results including the velocity and pressure profile in the steam generator upper internals, as well as fluid mass flow passing through the sludge collector, are presented and discussed for various configurations of the sludge collector and loose parts weir. Sludge particle collection rates are estimated using an empirical correlation

  3. THE BIMODAL DISTRIBUTION: DEVELOPMENT OF THE CONCEPT OF FINE AND COARSE PARTICLES AS SEPARATE AND DISTINCT COMPONENTS OF AIRBORNE PARTICULATE MATTER

    Science.gov (United States)

    In the early 1970s, it was understood that combustion particles were formed mostly in sizes below 1 um diameter, and windblown dust was suspended in sizes mostly above 1 um diameter. However, particle size distribution was thought of as a single mode. Particles were thought to f...

  4. Rapid Variability Generated at Relativistic Shocks Simulated by Particle-in- Cell Code

    Science.gov (United States)

    Nishikawal, Ken-Ichi; Niemiec, J.; Medvedev, M.; Sol, H.; Zhang, B.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J.; Pohl, M.; Hartmann, D. H.; Fishman, G. J.

    2010-01-01

    Plasma instabilities excited in collisionless shocks are responsible for particle acceleration. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electronpositron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection behind the shock. We calculate the radiation from deflected electrons in the turbulent magnetic fields. Radiation from electrons near the trailing shock will be variable due to fluctuations of density and electromagnetic fields. The properties of this radiation may be important for rapid variability in relativistic jets such as AGN jets and blazars.

  5. Surface charge properties of red mud particles generated from Chinese diaspore bauxite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kun-yu; HU Hui-ping; ZHANG Li-juan; CHEN Qi-yuan

    2008-01-01

    Acid/basic potentiometric titration can be used to quantify the red mud surface charge properties. The amount of surface active -OH groups and surface charge density on the red mud particles generated from Chinese diaspore bauxite were evaluated from the acid/basic potentiometric titration data in 0.1 mol/L or 0.5 molL NaCI solution. The results show that the adsorption of sodium polyacrylate(SPA) on the red mud surface causes the increase of the surface active -OH groups, which makes the point of zero charge(PZC) shift to a lower pH value. However, the adsorption of polyacrylamide(PAM) causes little change. As the concentration of NaCl solution increases, the surface charge becomes more positive in acidic solution and more negative in alkaline solution, which can be attributed to the presence of a porous surface gel coating on the red mud particles.

  6. Generating function for particle-number probability distribution in directed percolation

    International Nuclear Information System (INIS)

    We derive a generic expression for the generating function (GF) of the particle-number probability distribution (PNPD) for a simple reaction diffusion model that belongs to the directed percolation universality class. Starting with a single particle on a lattice, we show that the GF of the PNPD can be written as an infinite series of cumulants taken at zero momentum. This series can be summed up into a complete form at the level of a mean-field approximation. Using the renormalization group techniques, we determine logarithmic corrections for the GF at the upper critical dimension. We also find the critical scaling form for the PNPD and check its universality numerically in one dimension. The critical scaling function is found to be universal up to two non-universal metric factors

  7. Adiabatic electron response and solitary wave generation by trapped particle nonlinearity in a hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Debraj; Sharma, Devendra [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2014-10-15

    The finite amplitude ion acoustic waves that trap electrons modify the structure of the evolving nonlinear soliton solutions. In the numerical simulations, self-consistently generated solitary waves are studied that emerge as a result of a current driven microinstability growing the ion acoustic mode in a collisionless Vlasov plasma. The growth saturates as a result of nonlinear effects governed by a combination of nonlinearities originating from the hydrodynamic model and kinetic particle trapping effects. The resulting solitary waves also coexist with a finite current and an electron plasma wave capable of perturbing the trapping potential. The results of multiscale simulation are analyzed and characterized following the kinetic prescription of undamped trapped particle mode in the form of phase space vortex solutions that are generalized form of Sagdeev's solitons and obey the solutions of a modified Korteweg-de Vries equation, accounting for a stronger nonlinearity originating from the electron trapping.

  8. A particle dark matter footprint on the first generation of stars

    CERN Document Server

    Lopes, Ilidio

    2014-01-01

    Dark matter particles with properties identical to dark matter candidates that are hinted at by several international collaborations dedicated to experimental detection of dark matter (DAMA, COGENT, CRESST and CDMS-II, although not, most notably, by LUX), and which also have a dark matter asymmetry identical to the observed baryon asymmetry (Planck and Wilkinson Microwave Anisotropy Probe), may produce a significant impact on the evolution of the first generation of low-metallicity stars. The lifetimes of these stars in different phases of stellar evolution are significantly extended, namely, in the pre-main sequence, main sequence, and red giant phases. In particular, intermediate-mass stars in the red giant phase experience significant changes in their luminosity and chemical composition. The annihilations of dark matter particles affect the interior of the star in such a way that the $3\\alpha-$reaction becomes less efficient in the production of carbon and oxygen. This dark matter effect contradicts the ex...

  9. The lattice distortion of nickel particles generated by spark discharge in hydrocarbon dielectric mediums

    Science.gov (United States)

    Liu, Yifan; Li, Xianglong; Li, Yan; Zhao, Zhankui; Bai, Fushi

    2016-03-01

    Nickel particles were prepared by the ultrasound-aided spark discharge in pure water and hydrocarbons (kerosene and EDM fluid). The element composition and lattice structure were analyzed by EDS and XRD, respectively. The EDS indicated a high-purity powder was generated in pure water. For hydrocarbons, the carbon was detected as the majority impurity dissolved into the Ni interstitial sites, and the quantitative XRD revealed that the peak positions are lower than those of the corresponding perfect Ni crystal. The d-spacing deviation increases with the effect of ultrasound in hydrocarbons, while the distortion is negligible for pure water. We reported the composition, interatomic distances, and distortion of the Ni particles resulting from C doping. These findings revealed a new method to synthesize the solid solution via the spark discharge.

  10. Generating Irregular Models for 3D Spherical-Particle-Based Numerical Methods

    Directory of Open Access Journals (Sweden)

    Gang-Hai Huang

    2013-01-01

    Full Text Available The realistic representation of an irregular geological body is essential to the construction of a particle simulation model. A three-dimensional (3D sphere generator for an irregular model (SGIM, which is based on the platform of Microsoft Foundation Classes (MFC in VC++, is developed to accurately simulate the inherent discontinuities in geological bodies. OpenGL is employed to visualize the modeling in the SGIM. Three key functions, namely, the basic-model-setup function, the excavating function, and the cutting function, are implemented. An open-pit slope is simulated using the proposed model. The results demonstrate that an extremely irregular 3D model of a geological body can be generated using the SGIM and that various types of discontinuities can be inserted to cut the model. The data structure of the model that is generated by the SGIM is versatile and can be easily modified to match various numerical calculation tools. This can be helpful in the application of particle simulation methods to large-scale geoengineering projects.

  11. The steady state of a particle in a vibrating box and possible application in short pulse generation of charged particles

    Indian Academy of Sciences (India)

    Nandan Jha; Sudhir R Jain

    2013-09-01

    In this paper the classical evolution of a particle is studied which bounces back and forth in a 1D vibrating cavity such that the reflection from the wall does not change the speed of the particle. A peculiar behaviour of the particle motion can be seen where the time evolution of the motion shows superposition of linear and oscillatory behaviour. In particular, the parameter range is found in which the particle oscillates between the walls in steady state as if the wall was static and it is showed that for these parameter ranges the particle settles to this steady state for all initial conditions. It is proposed that this phenomenon can be used to bunch charged particles in short pulses where the synchronization proposed in our model should work against the space charge effect in the charged particle bunch.

  12. Effects of volatile coatings on the morphology and optical detection of combustion-generated black carbon particles.

    Energy Technology Data Exchange (ETDEWEB)

    Bambha, Ray P.; Dansson, Mark Alex; Schrader, Paul E.; Michelsen, Hope A.

    2013-09-01

    We have measured time-resolved laser-induced incandescence (LII) from combustion-generated mature soot extracted from a burner and (1) coated with oleic acid or (2) coated with oleic acid and then thermally denuded using a thermodenuder. The soot samples were size selected using a differential mobility analyser and characterized with a scanning mobility particle sizer, centrifugal particle mass analyser, and transmission electron microscope. The results demonstrate a strong influence of coatings particle morphology and on the magnitude and temporal evolution of the LII signal. For coated particles higher laser fluences are required to reach LII signal levels comparable to those of uncoated particles. This effect is predominantly attributable to the additional energy needed to vaporize the coating while heating the particle. LII signals are higher and signal decay rates are significantly slower for thermally denuded particles relative to coated or uncoated particles, particularly at low and intermediate laser fluences.

  13. Modeling for Airborne Contamination

    International Nuclear Information System (INIS)

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

  14. Optimization of biomass fuelled systems for distributed power generation using Particle Swarm Optimization

    International Nuclear Information System (INIS)

    With sufficient territory and abundant biomass resources Spain appears to have suitable conditions to develop biomass utilization technologies. As an important decentralized power technology, biomass gasification and power generation has a potential market in making use of biomass wastes. This paper addresses biomass fuelled generation of electricity in the specific aspect of finding the best location and the supply area of the electric generation plant for three alternative technologies (gas motor, gas turbine and fuel cell-microturbine hybrid power cycle), taking into account the variables involved in the problem, such as the local distribution of biomass resources, transportation costs, distance to existing electric lines, etc. For each technology, not only optimal location and supply area of the biomass plant, but also net present value and generated electric power are determined by an own binary variant of Particle Swarm Optimization (PSO). According to the values derived from the optimization algorithm, the most profitable technology can be chosen. Computer simulations show the good performance of the proposed binary PSO algorithm to optimize biomass fuelled systems for distributed power generation. (author)

  15. The generation model of particle physics and the cosmological matter-antimatter asymmetry problem

    CERN Document Server

    Robson, B A

    2016-01-01

    The matter-antimatter asymmetry problem, corresponding to the virtual nonexistence of antimatter in the universe, is one of the greatest mysteries of cosmology. Within the framework of the Generation Model (GM) of particle physics, it is demonstrated that the matter-antimatter asymmetry problem may be understood in terms of the composite leptons and quarks of the GM. It is concluded that there is essentially no matter-antimatter asymmetry in the present universe and that the observed hydrogen-antihydrogen asymmetry may be understood in terms of statistical fluctuations associated with the complex many-body processes involved in the formation of either a hydrogen atom or an antihydrogen atom.

  16. Analysis on Measurement Calibration Specifications for Light-scattering Airborne Particle Counter%光散射尘埃粒子计数器的计量校准规范浅析

    Institute of Scientific and Technical Information of China (English)

    高志良; 季启政; 王慧; 袁亚飞

    2013-01-01

    光散射尘埃粒子计数器作为监测洁净环境的最主要仪器,已在各领域被广泛应用,其自身性能质量也越来越被关注.近年来,国内外形成了多种光散射尘埃粒子计数器计量校准方法,其相互之间均存在着一定差异,这给仪器生产厂家以及计量机构带来了一定困难.本文简要分析了光散射尘埃粒子计数器相关国内外技术标准的研究现状,并重点对国内目前使用较为广泛的JJF 1190和GJB/J 5416标准进行了对比分析.%As the main equipment to monitor the clean space,the light-scattering airborne particle counter has been widely used and caught more attention on its capability.In recent years,many kinds of measurements of the airborne particle counter have been made,which brings troubles to the manufacturing corporations and measurement organizations.This paper introduces the domestic and international counter measurement standards,and focuses on the comparison and analysis of domestic standards JJF 1190 and GJB/J 5416.

  17. Measuring airborne microorganisms and dust from livestock houses

    OpenAIRE

    Yang Zhao, Yang

    2011-01-01

      Airborne transmission has been suspected to be responsible for epidemics of highly infectious disease in livestock production. In such transmission, the pathogenic microorganisms may associate with dust particles. However, the extent to which airborne transmission plays a role in the spread of diseases between farms, and the relationship between microorganisms and dust remain unclear. In order to better understand airborne transmission and to set up effective control techniques, this s...

  18. Generation expansion planning in Pool market: A hybrid modified game theory and particle swarm optimization

    Energy Technology Data Exchange (ETDEWEB)

    Moghddas-Tafreshi, S.M. [Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Shayanfar, H.A. [Center of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Saliminia Lahiji, A. [Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Rabiee, A. [Center of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Aghaei, J., E-mail: aghaei@iust.ac.i [Department of Electrical and Electronic Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of)

    2011-02-15

    Unlike the traditional policy, Generation Expansion Planning (GEP) problem in competitive framework is complicated. In the new policy, each GENeration COmpany (GENCO) decides to invest in such a way that obtains as much profit as possible. This paper presents a new hybrid algorithm to determine GEP in a Pool market. The proposed algorithm is divided in two programming levels: master and slave. In the master level a modified game theory (MGT) is proposed to evaluate the contrast of GENCOs by the Independent System Operator (ISO). In the slave level, a particle swarm optimization (PSO) method is used to find the best solution of each GENCO for decision-making of investment. The validity of the proposed method is examined in the case study including three GENCOs with multi-types of power plants. The results show that the presented method is both satisfactory and consistent with expectation.

  19. Applying Sequential Particle Swarm Optimization Algorithm to Improve Power Generation Quality

    Directory of Open Access Journals (Sweden)

    Abdulhafid Sallama

    2014-10-01

    Full Text Available Swarm Optimization approach is a heuristic search method whose mechanics are inspired by the swarming or collaborative behaviour of biological populations. It is used to solve constrained, unconstrained, continuous and discrete problems. Swarm intelligence systems are widely used and very effective in solving standard and large-scale optimization, provided that the problem does not require multi solutions. In this paper, particle swarm optimisation technique is used to optimise fuzzy logic controller (FLC for stabilising a power generation and distribution network that consists of four generators. The system is subject to different types of faults (single and multi-phase. Simulation studies show that the optimised FLC performs well in stabilising the network after it recovers from a fault. The controller is compared to multi-band and standard controllers.

  20. Generation expansion planning in Pool market: A hybrid modified game theory and particle swarm optimization

    International Nuclear Information System (INIS)

    Unlike the traditional policy, Generation Expansion Planning (GEP) problem in competitive framework is complicated. In the new policy, each GENeration COmpany (GENCO) decides to invest in such a way that obtains as much profit as possible. This paper presents a new hybrid algorithm to determine GEP in a Pool market. The proposed algorithm is divided in two programming levels: master and slave. In the master level a modified game theory (MGT) is proposed to evaluate the contrast of GENCOs by the Independent System Operator (ISO). In the slave level, a particle swarm optimization (PSO) method is used to find the best solution of each GENCO for decision-making of investment. The validity of the proposed method is examined in the case study including three GENCOs with multi-types of power plants. The results show that the presented method is both satisfactory and consistent with expectation.

  1. Airborne geoid determination

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Bastos, L.; Gidskehaug, A.; Meyer, U.; Timmen, L.

    2000-01-01

    Airborne geoid mapping techniques may provide the opportunity to improve the geoid over vast areas of the Earth, such as polar areas, tropical jungles and mountainous areas, and provide an accurate "seam-less" geoid model across most coastal regions. Determination of the geoid by airborne methods...... relies on the development of airborne gravimetry, which in turn is dependent on developments in kinematic GPS. Routine accuracy of airborne gravimetry are now at the 2 mGal level, which may translate into 5-10 cm geoid accuracy on regional scales. The error behaviour of airborne gravimetry is well...

  2. A particle dark matter footprint on the first generation of stars

    International Nuclear Information System (INIS)

    Dark matter particles with properties identical to those of dark matter candidates hinted at by several international collaborations dedicated to the experimental detection of dark matter (DAMA, COGENT, CRESST, and CDMS-II, although not, most notably, by LUX), which also have a dark matter asymmetry that is identical to the observed baryon asymmetry (Planck and Wilkinson Microwave Anisotropy Probe), may produce a significant impact on the evolution of the first generation of low-metallicity stars. The lifetimes of these stars in different phases of stellar evolution are significantly extended, namely, in the pre-main sequence, main sequence, and red giant phases. In particular, intermediate-mass stars in the red giant phase experience significant changes in their luminosity and chemical composition. The annihilations of dark matter particles affect the interior of the star in such a way that the 3α reaction becomes less efficient in the production of carbon and oxygen. This dark matter effect contradicts the excess of carbon and other metals observed today in stars of low mass and low metallicity. Hence, we can impose an upper limit on the dark matter halo density, and therefore on the redshift, at which the first generation of low-metallicity stars formed.

  3. On the spatiotemporal correlations in a linear stochastic field generated by non-interacting particles: Theory

    International Nuclear Information System (INIS)

    Highlights: • A stochastic measure is introduced to describe the spatio-temporal correlations. • A master equation governing the behavior of this measure is obtained. • The master equation is projected onto a much smaller subspace. • A discretization scheme is developed to solve the corresponding equations. • The numerical results show the accuracy of this method. - Abstract: Many of the physical macroscopic quantities could be explained as the result of a collection of microscopic particles which act independent of each-other, in a linear fashion. Since the physical laws of the interaction of these particles with their surrounding medium are non-deterministic, one could think of these particles as the generators of a linear stochastic field. In this paper, we have introduced a derivation which has yielded an equation for the spatiotemporal correlations in such a field. The derivation is simple and extendable to include the behavior of many physical particles. A simple numerical algorithm has been devised to solve the obtained initial value integrodifferential equation and a computer program has been developed accordingly. The temporal correlations in four benchmark problems, i.e. a three dimensional one group fissile cube, two multi-region one group slabs and a two-group multi-region slab, have been obtained and compared with direct Monte Carlo simulations which show the accuracy of the method. Finally, these benchmarks show some possible applications of this formulation, e.g. generalizing the Rossi-alpha formula and extraction of the average neutron velocity in a steady-state reactor core

  4. Size distribution and chemical composition of airborne particles in south-eastern Finland during different seasons and wildfire episodes in 2006

    International Nuclear Information System (INIS)

    The inorganic main elements, trace elements and PAHs were determined from selected PM1, PM2.5 and PM10 samples collected at the Nordic background station in Virolahti during different seasons and during the wildfire episodes in 2006. Submicron particles are those most harmful to human beings, as they are able to penetrate deep into the human respiratory system and may cause severe health effects. About 70-80%, of the toxic trace elements, like lead, cadmium, arsenic and nickel, as well as PAH compounds, were found in particles smaller than 1 μm. Furthermore, the main part of the copper, zinc, and vanadium was associated with submicron particles. In practice, all the PAHs found in PM10 were actually in PM2.5. For PAHs and trace elements, it is more beneficial to analyse the PM2.5 or even the PM1 fraction instead of PM10, because exclusion of the large particles reduces the need for sample cleaning to minimize the matrix effects during the analysis. During the wildfire episodes, the concentrations of particles smaller than 2.5 μm, as well as those of submicron particles, increased, and also the ratio PM1/PM10 increased to about 50%. On the fire days, the mean potassium concentration was higher in all particle fractions, but ammonium and nitrate concentrations rose only in particles smaller than 1.0 μm. PAH concentrations rose even to the same level as in winter.

  5. Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution

    Science.gov (United States)

    Shen, H.; Barakat, A. I.; Anastasio, C.

    2011-01-01

    Epidemiological studies have shown a correlation between exposure to ambient particulate matter (PM) and adverse health effects. One proposed mechanism of PM-mediated health effects is the generation of reactive oxygen species (ROS) - e.g., superoxide (•O2-), hydrogen peroxide (HOOH), and hydroxyl radical (•OH) - followed by oxidative stress. There are very few quantitative, specific measures of individual ROS generated from PM, but this information would help to more quantitatively address the link between ROS and the health effects of PM. To address this gap, we quantified the generation of HOOH by PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California during summer and winter from 2006 to 2009. HOOH was quantified by HPLC after extracting the PM in a cell-free, phosphate-buffered saline (PBS) solution with or without 50 μM ascorbate (Asc). Our results show that the urban PM generally generates much more HOOH than the rural PM but that there is no apparent seasonal difference in HOOH generation. In nearly all of the samples the addition of a physiologically relevant concentration of Asc greatly enhances HOOH formation, but a few of the coarse PM samples were able to generate a considerable amount of HOOH in the absence of added Asc, indicating the presence of unknown reductants. Normalized by air volume, the fine PM (PM2.5) generally makes more HOOH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm), primarily because the mass concentration of PM2.5 is much higher than that of PMcf. However, normalized by PM mass, the coarse PM typically generates more HOOH than the fine PM. The amount of HOOH produced by SJV PM is reduced on average by (78 ± 15)% when the transition metal chelator desferoxamine (DSF) is added to the extraction solution, indicating that transition metals play a dominant role in HOOH generation. By measuring calibration curves of HOOH generation from copper, and quantifying copper

  6. Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution

    Directory of Open Access Journals (Sweden)

    H. Shen

    2010-09-01

    measuring calibration curves of HOOH generation from copper, and quantifying copper concentrations in our particle extracts, we find that PBS-soluble copper is primarily responsible for HOOH production by the Fresno PM. Extrapolating our results to expected concentrations of PM-derived HOOH in human lungs suggests that typical daily PM exposures in the San Joaquin Valley are unlikely to cause HOOH-mediated acute health effects, but that very high PM events might lead to cytotoxic levels of pulmonary HOOH.

  7. Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution

    Directory of Open Access Journals (Sweden)

    H. Shen

    2011-01-01

    generation. By measuring calibration curves of HOOH generation from copper, and quantifying copper concentrations in our particle extracts, we find that PBS-soluble copper is primarily responsible for HOOH production by the Fresno PM. Extrapolating our results to expected concentrations of PM-derived HOOH in human lung lining fluid suggests that typical daily PM exposures in the San Joaquin Valley are unlikely to cause HOOH-mediated acute health effects, but that very high PM events might lead to cytotoxic levels of pulmonary HOOH.

  8. Effect of airborne particle abrasion protocols on surface topography of Y-TZP ceramic Efeito do protocolo de jateamento com partículas na topografia da superfície de uma cerâmica Y-TZP

    Directory of Open Access Journals (Sweden)

    J. R. C. Queiroz

    2012-06-01

    Full Text Available This study aimed to evaluate Y-TZP surface after different airborne particle abrasion protocols. Seventy-six Y-TZP ceramic blocks (5×4×4 mm³ were sintered and polished. Specimens were randomly divided into 19 groups (n=4 according to control group and 3 factors: a protocol duration (2 and 4 s; b particle size (30 µm, alumina coated silica particle; 45 µm, alumina particle; and 145 µm, alumina particle and; c pressure (1.5, 2.5 and 4.5 bar. Airborne particle abrasion was performed following a strict protocol. For qualitative and quantitative results, topography surfaces were analyzed in a digital optical profilometer (Interference Microscopic, using different roughness parameters (Ra, Rq, Rz, X-crossing, Mr1, Mr2 and Sdr and 3D images. Surface roughness also was analyzed following the primer and silane applications on Y-TZP surfaces. One-way ANOVA revealed that treatments (application period, particle size and pressure of particle blasting provided significant difference for all roughness parameters. The Tukey test determined that the significant differences between groups were different among roughness parameters. In qualitative analysis, the bonding agent application reduced roughness, filing the valleys in the surface. The protocols performed in this study verified that application period, particle size and pressure influenced the topographic pattern and amplitude of roughness.O objetivo deste estudo foi avaliar a superfície de uma cerâmica à base de zircônia tetragonal estabilizada por ítria (Y-TZP após diferentes protocolos de jateamento com partículas. Setenta e seis blocos cerâmicos de Y-TZP (5 x 4 x 4 mm³ foram sinterizados e polidos. As amostras foram randomicamente divididas em 19 grupos (n=4 sendo um controle e 18 grupos utilizando 3 fatores: a tempo (2 e 4 s; b tamanho de partícula (30 µm - partículas de alumina revestida por sílica; 45 µm - partículas de alumina; 145 µm - partículas de alumina e; c pressão (1

  9. Suspended particle interactions

    International Nuclear Information System (INIS)

    The objectives of the study are to determine the factors influencing the extent of Pu deposition from airborne effluents onto foliage, the potential for the resuspension of Pu from the leaf surface and the extent of Pu uptake and translocation by the plant. Using a low-wind-speed aerosol plant-exposure chamber, polydispersed aerosols were generated, particles characterized with respect to AMAD and GSD, and parameters such as deposition rate and deposition velocity evaluated for the plant canopy. The fate of surface deposited Pu compounds with respect to chemical modification and leachability was evaluated by leaching with synthetic ''rainwater'' and 0.1 percent HNO3 solutions

  10. Laboratory-generated mixtures of mineral dust particles with biological substances: characterization of the particle mixing state and immersion freezing behavior

    Science.gov (United States)

    Augustin-Bauditz, Stefanie; Wex, Heike; Denjean, Cyrielle; Hartmann, Susan; Schneider, Johannes; Schmidt, Susann; Ebert, Martin; Stratmann, Frank

    2016-05-01

    Biological particles such as bacteria, fungal spores or pollen are known to be efficient ice nucleating particles. Their ability to nucleate ice is due to ice nucleation active macromolecules (INMs). It has been suggested that these INMs maintain their nucleating ability even when they are separated from their original carriers. This opens the possibility of an accumulation of such INMs in soils, resulting in an internal mixture of mineral dust and INMs. If particles from such soils which contain biological INMs are then dispersed into the atmosphere due to wind erosion or agricultural processes, they could induce ice nucleation at temperatures typical for biological substances, i.e., above -20 up to almost 0 °C, while they might be characterized as mineral dust particles due to a possibly low content of biological material. We conducted a study within the research unit INUIT (Ice Nucleation research UnIT), where we investigated the ice nucleation behavior of mineral dust particles internally mixed with INM. Specifically, we mixed a pure mineral dust sample (illite-NX) with ice active biological material (birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). A very important topic concerning the investigations presented here as well as for atmospheric application is the characterization of the mixing state of aerosol particles. In the present study we used different methods like single-particle aerosol mass spectrometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), and a Volatility-Hygroscopicity Tandem Differential Mobility Analyser (VH-TDMA) to investigate the mixing state of our generated aerosol. Not all applied methods performed similarly well in detecting small amounts of biological material on the mineral dust particles. Measuring the hygroscopicity/volatility of the mixed particles with the VH-TDMA was the most

  11. Connection of European particle therapy centers and generation of a common particle database system within the European ULICE-framework

    OpenAIRE

    Kessel Kerstin A; Bougatf Nina; Bohn Christian; Habermehl Daniel; Oetzel Dieter; Bendl Rolf; Engelmann Uwe; Orecchia Roberto; Fossati Piero; Pötter Richard; Dosanjh Manjit; Debus Jürgen; Combs Stephanie E

    2012-01-01

    Abstract Background To establish a common database on particle therapy for the evaluation of clinical studies integrating a large variety of voluminous datasets, different documentation styles, and various information systems, especially in the field of radiation oncology. Methods We developed a web-based documentation system for transnational and multicenter clinical studies in particle therapy. 560 patients have been treated from November 2009 to September 2011. Protons, carbon ions or a co...

  12. Airborne Single Particle Mass Spectrometers (SPLAT II & miniSPLAT) and New Software for Data Visualization and Analysis in a Geo-Spatial Context

    Energy Technology Data Exchange (ETDEWEB)

    Zelenyuk, Alla; Imre, D.; Wilson, Jacqueline M.; Zhang, Zhiyuan; Wang, Jun; Mueller, Klaus

    2015-02-01

    Understanding the effect of aerosols on climate requires knowledge of the size and chemical composition of individual aerosol particles - two fundamental properties that determine an aerosol’s optical properties and ability to serve as cloud condensation or ice nuclei. Here we present miniSPLAT, our new aircraft compatible single particle mass spectrometer, that measures in-situ and in real-time size and chemical composition of individual aerosol particles with extremely high sensitivity, temporal resolution, and sizing precision on the order of a monolayer. miniSPLAT operates in dual data acquisition mode to measure, in addition to single particle size and composition, particle number concentrations, size distributions, density, and asphericity with high temporal resolution. When compared to our previous instrument, SPLAT II, miniSPLAT has been significantly reduced in size, weight, and power consumption without loss in performance. We also present ND-Scope, our newly developed interactive visual analytics software package. ND-Scope is designed to explore and visualize the vast amount of complex, multidimensional data acquired by our single particle mass spectrometers, along with other aerosol and cloud characterization instruments on-board aircraft. We demonstrate that ND-Scope makes it possible to visualize the relationships between different observables and to view the data in a geo-spatial context, using the interactive and fully coupled Google Earth and Parallel Coordinates displays. Here we illustrate the utility of ND-Scope to visualize the spatial distribution of atmospheric particles of different compositions, and explore the relationship between individual particle composition and their activity as cloud condensation nuclei.

  13. Hawking Radiation of Mass Generating Particles from Dyonic Reissner-Nordström Black Hole

    Science.gov (United States)

    Sakalli, I.; Övgün, A.

    2016-09-01

    The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyse the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner-Nordström black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed in reading the standard Hawking temperature of the dyonic Reissner-Nordström black hole.

  14. Test particle transport in the electric potential generated by edge turbulence

    International Nuclear Information System (INIS)

    Numerous experimental data show the existence of non-diffusive transport in tokamak plasmas. This article deals with the trajectories of test particles going through edge turbulence in scrape off layer (that is in the region where magnetic field lines are open). The interchange mechanism of the turbulence tends to generate convective cells by electrical shift, the radial extension is comparable to the size of the system. The resulting transport is mainly a ballistic-type transport whose time features are very short. Whenever the transport is directed towards outside, it appears profitable because it produces a broadening of the scrape off layer. On the contrary, the existence of ballistic trajectories directed towards the inside of the discharge implies an important contamination of the plasma by impurities coming from the wall. (A.C.)

  15. Hawking Radiation of Mass Generating Particles From Dyonic Reissner Nordstrom Black Hole

    CERN Document Server

    Sakalli, I

    2016-01-01

    The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyze the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner-Nordstr\\"{o}m black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed to read the standard Hawking temperature of the dyonic Reissner-Nordstr\\"{o}m black hole.

  16. Particle swarm optimization for discrete-time inverse optimal control of a doubly fed induction generator.

    Science.gov (United States)

    Ruiz-Cruz, Riemann; Sanchez, Edgar N; Ornelas-Tellez, Fernando; Loukianov, Alexander G; Harley, Ronald G

    2013-12-01

    In this paper, the authors propose a particle swarm optimization (PSO) for a discrete-time inverse optimal control scheme of a doubly fed induction generator (DFIG). For the inverse optimal scheme, a control Lyapunov function (CLF) is proposed to obtain an inverse optimal control law in order to achieve trajectory tracking. A posteriori, it is established that this control law minimizes a meaningful cost function. The CLFs depend on matrix selection in order to achieve the control objectives; this matrix is determined by two mechanisms: initially, fixed parameters are proposed for this matrix by a trial-and-error method and then by using the PSO algorithm. The inverse optimal control scheme is illustrated via simulations for the DFIG, including the comparison between both mechanisms. PMID:24273145

  17. The measurement of abrasive particles velocities in the process of abrasive water jet generation

    Czech Academy of Sciences Publication Activity Database

    Zeleňák, Michal; Foldyna, Josef; Říha, Zdeněk

    Melville : American Institute of Physics Inc, 2014 - (Lenhard, R.; Kaduchova, K.), s. 276-280 ISBN 978-0-7354-1244-6. ISSN 0094-243X. - (AIP Conference Proceedings. 1608). [The Application of experimental and numerical method s in fluid mechanics and energetics 2014 /19./. Liptovský Ján (SK), 09.04.2014-11.04.2014] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MPO FR-TI3/733 Institutional support: RVO:68145535 Keywords : abrasive cutting head * velocities of abrasive particles * abrasive water jet generation Subject RIV: JQ - Machines ; Tools http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4892749

  18. Influence of the power on the particles generated in a low pressure radio frequency nitrogen-rich methane discharge

    International Nuclear Information System (INIS)

    Particles are generated in low pressure radio frequency (13.56 MHz) CH4/N2 discharges containing 90% of nitrogen. The influence of the radio frequency power supply on the particle presence within the plasma is studied. Particles are evidenced by laser light scattering. The particle formation leads to modifications in the discharge electrical parameters such as the dc self-bias voltage and the phase angle third harmonic. The plasma is analyzed by optical emission spectroscopy by following the temporal evolution of excited species such as CN, N2, N2+, Ar, and He. Finally, the particle morphology and size are analyzed by scanning electron microscopy. The correlation between these results allows a better understanding of the power influence on the particle growth within the plasma

  19. Modelling magnetite particle deposition in nuclear steam generators and comparisons with plant data

    International Nuclear Information System (INIS)

    A computer code called SLUDGE has been developed that can be used to model secondary-side steam generator (SG) fouling as a function of time and operating conditions while still providing details of the deposit distribution throughout the SG. Tube deposits are predicted to grow at average rates of 4.4 and 1.1 μm/a on the hot side and cold side of the bundle, respectively. This is in good agreement with available plant data. SLUDGE under-predicts the magnitude of the tubesheet deposit, which implies that mechanisms in addition to gravitational settling may be responsible. One such mechanism, centrifugal separation of particles from the fluid streamlines, increased deposition towards the periphery of the tubesheet, but did not predict a realistic sludge pile. Comparison between the deposits on the horizontal surfaces of the tube support plates and the tubesheet suggests that the rate of particle removal at the tubesheet may have been overestimated. SLUDGE predicts a kidney-bean shaped sludge pile on the tubesheet when the re-entrainment rate is set equal to zero. (author). 17 refs., 1 tab., 6 figs

  20. Automating methods to improve precision in Monte-Carlo event generation for particle colliders

    Energy Technology Data Exchange (ETDEWEB)

    Gleisberg, Tanju

    2008-07-01

    The subject of this thesis was the development of tools for the automated calculation of exact matrix elements, which are a key for the systematic improvement of precision and confidence for theoretical predictions. Part I of this thesis concentrates on the calculations of cross sections at tree level. A number of extensions have been implemented in the matrix element generator AMEGIC++, namely new interaction models such as effective loop-induced couplings of the Higgs boson with massless gauge bosons, required for a number of channels for the Higgs boson search at LHC and anomalous gauge couplings, parameterizing a number of models beyond th SM. Further a special treatment to deal with complicated decay chains of heavy particles has been constructed. A significant effort went into the implementation of methods to push the limits on particle multiplicities. Two recursive methods have been implemented, the Cachazo-Svrcek-Witten recursion and the colour dressed Berends-Giele recursion. For the latter the new module COMIX has been added to the SHERPA framework. The Monte-Carlo phase space integration techniques have been completely revised, which led to significantly reduced statistical error estimates when calculating cross sections and a greatly improved unweighting efficiency for the event generation. Special integration methods have been developed to cope with the newly accessible final states. The event generation framework SHERPA directly benefits from those new developments, improving the precision and the efficiency. Part II was addressed to the automation of QCD calculations at next-to-leading order. A code has been developed, that, for the first time fully automates the real correction part of a NLO calculation. To calculate the correction for a m-parton process obeying the Catani-Seymour dipole subtraction method the following components are provided: 1. the corresponding m+1-parton tree level matrix elements, 2. a number dipole subtraction terms to remove

  1. Automating methods to improve precision in Monte-Carlo event generation for particle colliders

    International Nuclear Information System (INIS)

    The subject of this thesis was the development of tools for the automated calculation of exact matrix elements, which are a key for the systematic improvement of precision and confidence for theoretical predictions. Part I of this thesis concentrates on the calculations of cross sections at tree level. A number of extensions have been implemented in the matrix element generator AMEGIC++, namely new interaction models such as effective loop-induced couplings of the Higgs boson with massless gauge bosons, required for a number of channels for the Higgs boson search at LHC and anomalous gauge couplings, parameterizing a number of models beyond th SM. Further a special treatment to deal with complicated decay chains of heavy particles has been constructed. A significant effort went into the implementation of methods to push the limits on particle multiplicities. Two recursive methods have been implemented, the Cachazo-Svrcek-Witten recursion and the colour dressed Berends-Giele recursion. For the latter the new module COMIX has been added to the SHERPA framework. The Monte-Carlo phase space integration techniques have been completely revised, which led to significantly reduced statistical error estimates when calculating cross sections and a greatly improved unweighting efficiency for the event generation. Special integration methods have been developed to cope with the newly accessible final states. The event generation framework SHERPA directly benefits from those new developments, improving the precision and the efficiency. Part II was addressed to the automation of QCD calculations at next-to-leading order. A code has been developed, that, for the first time fully automates the real correction part of a NLO calculation. To calculate the correction for a m-parton process obeying the Catani-Seymour dipole subtraction method the following components are provided: 1. the corresponding m+1-parton tree level matrix elements, 2. a number dipole subtraction terms to remove

  2. Plasma Processing of SRF Cavities for the next Generation Of Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Vuskovic, Leposava

    2015-11-23

    The cost-effective production of high frequency accelerating fields are the foundation for the next generation of particle accelerators. The Ar/Cl2 plasma etching technology holds the promise to yield a major reduction in cavity preparation costs. Plasma-based dry niobium surface treatment provides an excellent opportunity to remove bulk niobium, eliminate surface imperfections, increase cavity quality factor, and bring accelerating fields to higher levels. At the same time, the developed technology will be more environmentally friendly than the hydrogen fluoride-based wet etching technology. Plasma etching of inner surfaces of standard multi-cell SRF cavities is the main goal of this research in order to eliminate contaminants, including niobium oxides, in the penetration depth region. Successful plasma processing of multi-cell cavities will establish this method as a viable technique in the quest for more efficient components of next generation particle accelerators. In this project the single-cell pill box cavity plasma etching system is developed and etching conditions are determined. An actual single cell SRF cavity (1497 MHz) is plasma etched based on the pill box cavity results. The first RF test of this plasma etched cavity at cryogenic temperature is obtained. The system can also be used for other surface modifications, including tailoring niobium surface properties, surface passivation or nitriding for better performance of SRF cavities. The results of this plasma processing technology may be applied to most of the current SRF cavity fabrication projects. In the course of this project it has been demonstrated that a capacitively coupled radio-frequency discharge can be successfully used for etching curved niobium surfaces, in particular the inner walls of SRF cavities. The results could also be applicable to the inner or concave surfaces of any 3D structure other than an SRF cavity.

  3. Airborne Single Particle Mass Spectrometers (SPLAT II & miniSPLAT) and New Software for Data Visualization and Analysis in a Geo-Spatial Context

    Science.gov (United States)

    Zelenyuk, Alla; Imre, Dan; Wilson, Jacqueline; Zhang, Zhiyuan; Wang, Jun; Mueller, Klaus

    2015-02-01

    Understanding the effect of aerosols on climate requires knowledge of the size and chemical composition of individual aerosol particles—two fundamental properties that determine an aerosol's optical properties and ability to serve as cloud condensation or ice nuclei. Here we present our aircraft-compatible single particle mass spectrometers, SPLAT II and its new, miniaturized version, miniSPLAT that measure in-situ and in real-time the size and chemical composition of individual aerosol particles with extremely high sensitivity, temporal resolution, and sizing precision on the order of a monolayer. Although miniSPLAT's size, weight, and power consumption are significantly smaller, its performance is on par with SPLAT II. Both instruments operate in dual data acquisition mode to measure, in addition to single particle size and composition, particle number concentrations, size distributions, density, and asphericity with high temporal resolution. We also present ND-Scope, our newly developed interactive visual analytics software package. ND-Scope is designed to explore and visualize the vast amount of complex, multidimensional data acquired by our single particle mass spectrometers, along with other aerosol and cloud characterization instruments on-board aircraft. We demonstrate that ND-Scope makes it possible to visualize the relationships between different observables and to view the data in a geo-spatial context, using the interactive and fully coupled Google Earth and Parallel Coordinates displays. Here we illustrate the utility of ND-Scope to visualize the spatial distribution of atmospheric particles of different compositions, and explore the relationship between individual particle compositions and their activity as cloud condensation nuclei.

  4. DRAGON: Monte Carlo generator of particle production from a fragmented fireball in ultrarelativistic nuclear collisions

    Science.gov (United States)

    Tomášik, Boris

    2009-09-01

    A Monte Carlo generator of the final state of hadrons emitted from an ultrarelativistic nuclear collision is introduced. An important feature of the generator is a possible fragmentation of the fireball and emission of the hadrons from fragments. Phase space distribution of the fragments is based on the blast wave model extended to azimuthally non-symmetric fireballs. Parameters of the model can be tuned and this allows to generate final states from various kinds of fireballs. A facultative output in the OSCAR1999A format allows for a comprehensive analysis of phase-space distributions and/or use as an input for an afterburner. Program summaryProgram title: DRAGON Catalogue identifier: AEDK_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDK_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 6383 No. of bytes in distributed program, including test data, etc.: 32 756 Distribution format: tar.gz Programming language: C++ Computer: PC Pentium 4, though no particular tuning for this machine was performed Operating system: Linux; the program has been successfully run on Gentoo Linux 2.6, RedHat Linux 9, Debian Linux 4.0, all with g++ compiler. It also ran successfully on MS Windows under Microsoft Visual C++ 2008 Express Edition as well as under cygwin/g++ RAM: 100 Mbytes Supplementary material: Sample output files from the test run, provided in the distribution, are available. Classification: 11.2 Nature of problem: Deconfined matter produced in ultrarelativistic nuclear collisions expands and cools down and eventually returns into the confined phase. If the expansion is fast, the fireball could fragment either due to spinodal decomposition or due to suddenly arising bulk viscous force. Particle abundances are reasonably well described with just a few parameters

  5. The Distribution of PM10 and PM2.5 Dust Particles Diameter in Airborne at the Cement Factory Neighboring Area, Citeureup - Bogor

    International Nuclear Information System (INIS)

    The distribution analysis in PM10 and PM2.5 dust particle diameter has been carried out at residence area around the cement factory, Citeureup - Bogor to estimate deposition of dust particles that is accepted by public. The dust particles were sampled at the dwellings by using a cascade impactor on four wind directions and 500, 1000, 1500, 2000, 2500, and 3000 m radius from the Plant one as the center of the cement factory at Citeureup - Bogor. Measurements at the north direction were the Gunung Putri, Kranggan, Bojong Nangka villages, and Gunung Putri dwellings. The south directions were Tarikolot and Pasir Mukti villages. The west directions were guest house, Puspanegara, Puspasari, and Citatah villages. The northwest directions were Puspanegara, Gunung Putri, Puspasari, and Kranggan villages. The analysis result showed that the diameter distribution of PM10 dust particles at outdoor is ranging from 0.4 to 4.7 μm, and has the weight percentage is high in average approximate 17.91 % of total dust weight on 500, 1000, 1500, 2000, 2500, and 3000 m radius. The distributions of indoor PM2.5 dust particles diameter show a stable 12.27 % weight percentage of total dust weight from 0.4 to 2.1 μm. (author)

  6. Microwaves in Airborne Surveillance

    OpenAIRE

    Christopher, S.

    2013-01-01

    The use of microwave spectrum is widespread due to its convenience. Therefore, enormous amount of information is available in the free space channel. Obviously, mining this channel for surveillance is quite common. Airborne surveillance offers significant advantages in military operations. This paper talks of the usage of microwaves in airborne surveillance systems, in general, and in the Indian airborne early warning and control (AEW&C) System, in particular. It brings out the multiple s...

  7. On the interaction between radon progeny and particles generated by electronic and traditional cigarettes

    Science.gov (United States)

    Vargas Trassierra, C.; Cardellini, F.; Buonanno, G.; De Felice, P.

    2015-04-01

    During their entire lives, people are exposed to the pollutants present in indoor air. Recently, Electronic Nicotine Delivery Systems, mainly known as electronic cigarettes, have been widely commercialized: they deliver particles into the lungs of the users but a "second-hand smoke" has yet to be associated to this indoor source. On the other hand, the naturally-occurring radioactive gas, i.e. radon, represents a significant risk for lung cancer, and the cumulative action of these two agents could be worse than the agents separately would. In order to deepen the interaction between radon progeny and second-hand aerosol from different types of cigarettes, a designed experimental study was carried out by generating aerosol from e-cigarette vaping as well as from second-hand traditional smoke inside a walk-in radon chamber at the National Institute of Ionizing Radiation Metrology (INMRI) of Italy. In this chamber, the radon present in air comes naturally from the floor and ambient conditions are controlled. To characterize the sidestream smoke emitted by cigarettes, condensation particle counters and scanning mobility particle sizer were used. Radon concentration in the air was measured through an Alphaguard ionization chamber, whereas the measurement of radon decay product in the air was performed with the Tracelab BWLM Plus-2S Radon daughter Monitor. It was found an increase of the Potential Alpha-Energy Concentration (PAEC) due to the radon decay products attached to aerosol for higher particle number concentrations. This varied from 7.47 ± 0.34 MeV L-1 to 12.6 ± 0.26 MeV L-1 (69%) for the e-cigarette. In the case of traditional cigarette and at the same radon concentration, the increase was from 14.1 ± 0.43 MeV L-1 to 18.6 ± 0.19 MeV L-1 (31%). The equilibrium factor increases, varying from 23.4% ± 1.11% to 29.5% ± 0.26% and from 30.9% ± 1.0% to 38.1 ± 0.88 for the e-cigarette and traditional cigarette, respectively. These growths still continue for long

  8. BioAerosol Mass Spectrometry: Reagentless Detection of Individual Airborne Spores and Other Bioagent Particles Based on Laser Desorption/Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Steele, P T

    2004-07-20

    Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. The investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. A statistical model has been developed to make these decisions and the resulting performance of a hypothetical BAMS system is quantitatively predicted. The predictions indicate that a BAMS system, with reasonably attainable characteristics, can operate with a very low false alarm rate (orders of magnitude lower than some currently fielded biodetectors) while still being sensitive to small concentrations of biological particles in a large range of environments. Proof-of-concept instruments, incorporating some of the modifications described here, have already performed well in independent testing.

  9. Airborne infections and modern building technology

    Energy Technology Data Exchange (ETDEWEB)

    LaForce, F.M.

    1986-01-01

    Over the last 30 yr an increased appreciation of the importance of airborne infection has evolved. The concept of droplet nuclei, infectious particles from 0.5 to 3 ..mu.. which stay suspended in air for long periods of time, has been accepted as an important determinant of infectivity. Important airborne pathogens in modern buildings include legionella pneumophila, Aspergillus sp., thermophilic actinomycetes, Mycobacterium tuberculosis, measles, varicella and rubella. Perhaps, the most important microbiologic threat to most buildings is L. pneumophila. This organism can multiply in water cooling systems and contaminate effluent air which can be drawn into a building and efficiently circulated throughout by existing ventilation systems. Hospitals are a special problem because of the concentration of immunosuppressed patients who are uniquely susceptible to airborne diseases such as aspergillosis, and the likelihood that patients ill from diseases that can be spread via the airborne route will be concentrated. Humidifiers are yet another problem and have been shown to be important in several outbreaks of allergic alveolitis and legionellosis. Control of airborne infections is largely an effort at identifying and controlling reservoirs of infection. This includes regular biocide treatment of cooling towers and evaporative condensers and identification and isolation of patients with diseases that may be spread via the airborne route.

  10. Impact of continuous particle injection on generation and decay of the magnetic field in collisionless shocks

    Science.gov (United States)

    Garasev, Mikhail; Derishev, Evgeny

    2016-09-01

    We present numerical simulations of the magnetic field turbulence in a collisionless electron-positron plasma with continuous injection of new pairs, which maintains the anisotropy in the particle distribution over a long time. With these simulations, we follow the evolution of a small (and, therefore, uniform) region in the fluid comoving frame to model the generation and decay of the magnetic field in shocks. The upstream is modified by two-photon pair production due to self-absorption of the shock's high-energy radiation. We find that the overall picture of the magnetic field build-up is consistent with the development of Weibel instability. However, the long-term injection of anisotropic pairs in the upstream leads to the formation of large-scale structures in the magnetic field, while small-scale structures are almost absent. We find that being amplified at the shock front, this magnetic field mostly preserves its large spatial scale and then slowly decays in the downstream on a time-scale approximately equal to the duration of the injection phase. The observed decay of the magnetic field is in exceptionally good agreement with predictions of the so-called phase mixing model. The generation of a long-lived magnetic field in relativistic collisionless shocks with an injection-modified upstream explains how they can efficiently produce the synchrotron radiation in gamma-ray bursts.

  11. Reactor Physics Parametric and Depletion Studies in Support of TRISO Particle Fuel Specification for the Next Generation Nuclear Plant

    Energy Technology Data Exchange (ETDEWEB)

    James W. Sterbentz; Bren Phillips; Robert L. Sant; Gray S. Chang; Paul D. Bayless

    2003-09-01

    Reactor physics calculations were initiated to answer several major questions related to the proposed TRISO-coated particle fuel that is to be used in the prismatic Very High Temperature Reactor (VHTR) or the Next Generation Nuclear Plant (NGNP). These preliminary design evaluation calculations help ensure that the upcoming fuel irradiation tests will test appropriate size and type of fuel particles for a future NGNP reactor design. Conclusions from these calculations are expected to confirm and suggest possible modifications to the current particle fuel parameters specified in the evolving Fuel Specification. Calculated results dispel the need for a binary fuel particle system, which is proposed in the General Atomics GT-MHR concept. The GT-MHR binary system is composed of both a fissile and fertile particle with 350- and 500- micron kernel diameters, respectively. For the NGNP reactor, a single fissile particle system (single UCO kernel size) can meet the reactivity and power cycle length requirements demanded of the NGNP. At the same time, it will provide substantial programmatic cost savings by eliminating the need for dual particle fabrication process lines and dual fuel particle irradiation tests required of a binary system. Use of a larger 425-micron kernel diameter single fissile particle (proposed here), as opposed to the 350-micron GT-MHR fissile particle size, helps alleviate current compact particle packing fractions fabrication limitations (<35%), improves fuel block loading for higher n-batch reload options, and tracks the historical correlation between particle size and enrichment (10 and 14 wt% U-235 particle enrichments are proposed for the NGNP). Overall, the use of the slightly larger kernel significantly broadens the NGNP reactor core design envelope and provides increased design margin to accommodate the (as yet) unknown final NGNP reactor design. Maximum power-peaking factors are calculated for both the initial and equilibrium NGNP cores

  12. Reactor Physics Parametric and Depletion Studies in Support of TRISO Particle Fuel Specification for the Next Generation Nuclear Plant

    International Nuclear Information System (INIS)

    Reactor physics calculations were initiated to answer several major questions related to the proposed TRISO-coated particle fuel that is to be used in the prismatic Very High Temperature Reactor (VHTR) or the Next Generation Nuclear Plant (NGNP). These preliminary design evaluation calculations help ensure that the upcoming fuel irradiation tests will test appropriate size and type of fuel particles for a future NGNP reactor design. Conclusions from these calculations are expected to confirm and suggest possible modifications to the current particle fuel parameters specified in the evolving Fuel Specification. Calculated results dispel the need for a binary fuel particle system, which is proposed in the General Atomics GT-MHR concept. The GT-MHR binary system is composed of both a fissile and fertile particle with 350- and 500-micron kernel diameters, respectively. For the NGNP reactor, a single fissile particle system (single UCO kernel size) can meet the reactivity and power cycle length requirements demanded of the NGNP. At the same time, it will provide substantial programmatic cost savings by eliminating the need for dual particle fabrication process lines and dual fuel particle irradiation tests required of a binary system. Use of a larger 425-micron kernel diameter single fissile particle (proposed here), as opposed to the 350-micron GT-MHR fissile particle size, helps alleviate current compact particle packing fractions fabrication limitations (<35%), improves fuel block loading for higher n-batch reload options, and tracks the historical correlation between particle size and enrichment (10 and 14 wt% U-235 particle enrichments are proposed for the NGNP). Overall, the use of the slightly larger kernel significantly broadens the NGNP reactor core design envelope and provides increased design margin to accommodate the (as yet) unknown final NGNP reactor design. Maximum power-peaking factors are calculated for both the initial and equilibrium NGNP cores

  13. 空中颗粒物对直流电晕放电影响研究现状:颗粒物空间电荷效应%Current Status of Study on the Effects of Airborne Particles on DC Corona Discharge:Space-charge Effect of Particles

    Institute of Scientific and Technical Information of China (English)

    陆家榆; 何堃; 马晓倩; 鞠勇; 谢莉

    2015-01-01

    Airborne suspended particles trapping electrons and ions give rise to space charges, which has an impact on DC corona discharge and electromagnetic environment of high voltage DC(HVDC) transmission lines. This is called space- charge effect of airborne suspended particles. Presently, severe air pollution and frequent occurrence of sand-dust, fog and haze are increasingly raging through China. The space-charge effect of airborne suspended particles charged by corona discharge will complicate the electromagnetic environment of HVDC transmission lines which is one of the important aspects impacting on the determination of the configuration parameters of the transmission lines. This makes the research on the effects of airborne suspended particles on electromagnetic environment of HVDC transmission lines crucial. Firstly, A detailed review on the research on the space charge-effect of suspended particles in the field of power transmission from the aspects of space charge density, charge of particles, total field ion current density at the ground level was conducted. Further, a summary of the research on the space charge effect in the fields of electrostatic precipitation, corona discharge of two- phase mixture of gas and solid, and dust plasma was presented. In the end, this paper pointed out the problems needed to be solved and gives the suggestions for the future research.%颗粒物捕获电子或离子以空间电荷形式对直流电晕放电产生影响。当前我国的大气污染日益严重,沙尘和霾天气频发。污染物中悬浮颗粒物荷电后带来的空间电荷效应将使高压直流输电线路周围的电磁环境复杂化,因此开展空中悬浮颗粒物对高压直流输电线路电磁环境影响的研究对指导直流输电线路的工程设计具有重要意义。该文对输电线路关于颗粒物空间电荷效应的研究历史进行回顾,并从空间电荷密度分布、颗粒物荷电量及其分布、地面合成电场和

  14. New generation of monolithic active pixel sensors for charged particle detection

    International Nuclear Information System (INIS)

    Vertex detectors are of great importance in particle physics experiments, as the knowledge of the event flavour is becoming an issue for the physics programme at Future Linear Colliders. Monolithic Active Pixel Sensors (MAPS) based on a novel detector structure have been proposed. Their fabrication is compatible with a standard CMOS process. The sensor is inseparable from the readout electronics, since both of them are integrated on the same, low-resistivity silicon wafer. The basic pixel configuration comprises only three MOS transistors and a diode collecting the charge through thermal diffusion. The charge is generated in the thin non-depleted epitaxial layer underneath the readout electronics. This approach provides, at low cost, a high resolution and thin device with the whole area sensitive to radiation. Device simulations using the ISE-TCAD package have been carried out to study the charge collection mechanism. In order to demonstrate the viability of the technique, four prototype chips have been fabricated using different submicrometer CMOS processes. The pixel gain has been calibrated using a 55Fe source and the Poisson sequence method. The prototypes have been exposed to high-energy particle beams at CERN. The tests proved excellent detection performances expressed in a single-track spatial resolution of 1.5 μm and detection efficiency close to 100%, resulting from a SNR ratio of more than 30. Irradiation tests showed immunity of MAPS to a level of a few times 1012 n/cm2 and a few hundred kRad of ionising radiation. The ideas for future work, including on-pixel signal amplification, double sampling operation and current mode pixel design are present as well. (author)

  15. A new gravitational wave generation algorithm for particle perturbations of the Kerr spacetime

    International Nuclear Information System (INIS)

    We present a new approach to solve the 2+1 Teukolsky equation for gravitational perturbations of a Kerr black hole. Our approach relies on a new horizon penetrating, hyperboloidal foliation of Kerr spacetime and spatial compactification. In particular, we present a framework for waveform generation from point-particle perturbations. Extensive tests of a time domain implementation in the Teukode code are presented. The code can efficiently deliver waveforms at future null infinity. The accuracy and convergence of the waveforms’ phase and amplitude is demonstrated. As a first application of the method, we compute the gravitational waveforms from inspiraling and coalescing black-hole binaries in the large-mass-ratio limit. The smaller mass black hole is modeled as a point particle whose dynamics is driven by an effective-one-body-resummed analytical radiation reaction force. We compare the analytical, mechanical angular momentum loss (computed using two different prescriptions) to the gravitational wave angular momentum flux. We find that higher-order post-Newtonian corrections are needed to improve the consistency for rapidly spinning binaries. We characterize the multipolar waveform as a function of the black-hole spin. Close to merger, the subdominant multipolar amplitudes (notably the m = 0 ones) are enhanced for retrograde orbits with respect to prograde ones. We argue that this effect mirrors nonnegligible deviations from the circularity of the dynamics during the late-plunge and merger phase. For the first time, we compute the gravitational wave energy flux flowing into the black hole during the inspiral using a time-domain formalism proposed by Poisson. Finally, a self-consistent, iterative method to compute the gravitational wave fluxes at leading-order in the mass of the particle is developed. The method can be used alternatively to the analytical radiation reaction in cases where the analytical information is poor or not sufficient. Specifically, we apply

  16. Connection of European particle therapy centers and generation of a common particle database system within the European ULICE-framework

    Directory of Open Access Journals (Sweden)

    Kessel Kerstin A

    2012-07-01

    Full Text Available Abstract Background To establish a common database on particle therapy for the evaluation of clinical studies integrating a large variety of voluminous datasets, different documentation styles, and various information systems, especially in the field of radiation oncology. Methods We developed a web-based documentation system for transnational and multicenter clinical studies in particle therapy. 560 patients have been treated from November 2009 to September 2011. Protons, carbon ions or a combination of both, as well as a combination with photons were applied. To date, 12 studies have been initiated and more are in preparation. Results It is possible to immediately access all patient information and exchange, store, process, and visualize text data, any DICOM images and multimedia data. Accessing the system and submitting clinical data is possible for internal and external users. Integrated into the hospital environment, data is imported both manually and automatically. Security and privacy protection as well as data validation and verification are ensured. Studies can be designed to fit individual needs. Conclusions The described database provides a basis for documentation of large patient groups with specific and specialized questions to be answered. Having recently begun electronic documentation, it has become apparent that the benefits lie in the user-friendly and timely workflow for documentation. The ultimate goal is a simplification of research work, better study analyses quality and eventually, the improvement of treatment concepts by evaluating the effectiveness of particle therapy.

  17. Connection of European particle therapy centers and generation of a common particle database system within the European ULICE-framework

    International Nuclear Information System (INIS)

    To establish a common database on particle therapy for the evaluation of clinical studies integrating a large variety of voluminous datasets, different documentation styles, and various information systems, especially in the field of radiation oncology. We developed a web-based documentation system for transnational and multicenter clinical studies in particle therapy. 560 patients have been treated from November 2009 to September 2011. Protons, carbon ions or a combination of both, as well as a combination with photons were applied. To date, 12 studies have been initiated and more are in preparation. It is possible to immediately access all patient information and exchange, store, process, and visualize text data, any DICOM images and multimedia data. Accessing the system and submitting clinical data is possible for internal and external users. Integrated into the hospital environment, data is imported both manually and automatically. Security and privacy protection as well as data validation and verification are ensured. Studies can be designed to fit individual needs. The described database provides a basis for documentation of large patient groups with specific and specialized questions to be answered. Having recently begun electronic documentation, it has become apparent that the benefits lie in the user-friendly and timely workflow for documentation. The ultimate goal is a simplification of research work, better study analyses quality and eventually, the improvement of treatment concepts by evaluating the effectiveness of particle therapy

  18. Visualization of aerosol particles generated by near infrared nano- and femtosecond laser ablation

    International Nuclear Information System (INIS)

    The expansion of aerosols generated by near infrared (NIR) nanosecond (ns) and femtosecond (fs) laser ablation (LA) of metals at atmospheric pressures was explored by laser-induced scattering. In order to achieve adequate temporal and spatial resolution a pulsed laser source was utilized for illuminating a 0.5 mm-wide cross section of the expanding aerosol. It could, for instance, be shown that NIR-ns-LA under quiescent argon atmosphere provokes the formation of a dense aerosol confined within a radially propagating vortex ring. The expansion dynamics achieved under these conditions were found to be fairly slow whereas the degree of aerosol dispersion for NIR-ns-LA using helium drastically increased due to its lower viscosity. As a consequence, the maximum diameter of expansion differed by a factor of approximately four. The trajectories of aerosol particles generated by NIR-ns-LA using argon could, furthermore, be simulated on the basis of computational fluid dynamics (CFD). For this purpose, a model inspired by the thermal character of NIR-ns-LA taking into account a sudden temperature build-up of 10,000 K at the position of the laser focus was implemented. In contrast, NIR-fs-LA generally resulted in extremely dynamic expansion patterns. Initial aerosol velocities derived from corresponding expansion plots varied from 10 m/s up to 30 m/s for fs-LA using argon and helium, respectively. Our results, moreover, indicate that fs-LA carried out under helium atmosphere favours a chaotic aerosol expansion. Analytical implications concerning, e.g. dispersion phenomena or the choice of the LA protocol and physical dimensions of future ablation cell designs are discussed

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

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    The research conducted by Textron Defense Systems (TDS) represents a potential new and innovative concept for dispersed coal liquefaction. The technical approach is generation of ultra-fine catalyst particles from supercritical solutions by rapid expansion of either catalyst only, or mixtures of catalyst and coal material in supersaturated solvents. The process of rapid expansion of supercritical fluid solutions was developed at Battelle`s Pacific Northwest Laboratories for the intended purpose of providing a new analytical technique for characterizing supercritical fluids. The concept forming the basis of this research is that ultra-fine particles can be generated from supercritical solutions by rapid expansion of either catalyst or catalyst/coal-material mixtures in supersaturated solvents, such as carbon dioxide or water. The focal point of this technique is the rapid transfer of low vapor pressure solute (i.e., catalyst), dissolved in the supercritical fluid solvent, to the gas phase as the solution is expanded through an orifice. The expansion process is characterized by highly nonequilibrium conditions which cause the solute to undergo extremely rapid supersaturation with respect to the solvent, leading to nucleation and particle growth resulting in nanometer size catalyst particles. A supercritical expansion system was designed and built by TDS at their Haverhill facility.

  20. Modelling airborne dispersion of coarse particulate material

    International Nuclear Information System (INIS)

    Methods of modelling the airborne dispersion and deposition of coarse particulates are presented, with the emphasis on the heavy particles identified as possible constituents of releases from damaged AGR fuel. The first part of this report establishes the physical characteristics of the irradiated particulate in airborne emissions from AGR stations. The second part is less specific and describes procedures for extending current dispersion/deposition models to incorporate a coarse particulate component: the adjustment to plume spread parameters, dispersion from elevated sources and dispersion in conjunction with building effects and plume rise. (author)

  1. Generation of the nonlocal quantum entanglement of three three-level particles by local operations

    Institute of Scientific and Technical Information of China (English)

    Jin Xing-Ri; Zhang Ying-Qiao; Jin Zhe; Zhang Shou

    2005-01-01

    We propose a scheme to realize the nonlocal quantum entanglement of three three-level particles by using a three-particle entangled state of three levels as a quantum channel with the aid of some local unitary transformations. This scheme can be directly generalized to the nonlocal quantum entanglement of N three-level particles.

  2. Airborne Particulate Threat Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

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

  3. Impact of continuous particle injection on generation and decay of the magnetic field in collisionless shocks

    CERN Document Server

    Garasev, Mikhail

    2016-01-01

    We present numerical simulations of the magnetic field turbulence in collisionless electron-positron plasma with continuous injection of new pairs, which maintains anisotropy in the particle distribution over long time. With these simulations we model generation and decay of the magnetic field in shocks, where the upstream is modified by two-photon pair production due to self-absorption of the shock's high-energy radiation. We find that the overall picture of magnetic field build-up is consistent with development of Weibel instability. However, the long-term injection of anisotropic pairs in the upstream leads to formation of large-scale structures in the magnetic field, while the small-scale structures are almost absent. Furthermore, we find that being amplified at the shock front this magnetic field mostly preserves its large spatial scale and then slowly decays in the downstream on a timescale approximately equal to duration of the injection phase. We observe that the decay of the magnetic field is in exce...

  4. Generation of excited coherent states for a charged particle in a uniform magnetic field

    International Nuclear Information System (INIS)

    We introduce excited coherent states, |β,α;nгЂ‰≔a†n|β,αгЂ‰, where n is an integer and states |β,αгЂ‰ denote the coherent states of a charged particle in a uniform magnetic field. States |β,αгЂ‰ minimize the Schrödinger-Robertson uncertainty relation while having the nonclassical properties. It has been shown that the resolution of identity condition is realized with respect to an appropriate measure on the complex plane. Some of the nonclassical features such as sub-Poissonian statistics and quadrature squeezing of these states are investigated. Our results are compared with similar Agarwal’s type photon added coherent states (PACSs) and it is shown that, while photon-counting statistics of |β,α,nгЂ‰ are the same as PACSs, their squeezing properties are different. It is also shown that for large values of |β|, while they are squeezed, they minimize the uncertainty condition. Additionally, it has been demonstrated that by changing the magnitude of the external magnetic field, Bext, the squeezing effect is transferred from one component to another. Finally, a new scheme is proposed to generate states |β,α;nгЂ‰ in cavities. 

  5. Motion generation of peristaltic mobile robot with particle swarm optimization algorithm

    Science.gov (United States)

    Homma, Takahiro; Kamamichi, Norihiro

    2015-03-01

    In developments of robots, bio-mimetics is attracting attention, which is a technology for the design of the structure and function inspired from biological system. There are a lot of examples of bio-mimetics in robotics such as legged robots, flapping robots, insect-type robots, fish-type robots. In this study, we focus on the motion of earthworm and aim to develop a peristaltic mobile robot. The earthworm is a slender animal moving in soil. It has a segmented body, and each segment can be shorted and lengthened by muscular actions. It can move forward by traveling expanding motions of each segment backward. By mimicking the structure and motion of the earthworm, we can construct a robot with high locomotive performance against an irregular ground or a narrow space. In this paper, to investigate the motion analytically, a dynamical model is introduced, which consist of a series-connected multi-mass model. Simple periodic patterns which mimic the motions of earthworms are applied in an open-loop fashion, and the moving patterns are verified through numerical simulations. Furthermore, to generate efficient motion of the robot, a particle swarm optimization algorithm, one of the meta-heuristic optimization, is applied. The optimized results are investigated by comparing to simple periodic patterns.

  6. Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

    International Nuclear Information System (INIS)

    With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, can detect nuclear warheads by their characteristic strong gamma-ray absorption, or can count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. 5 refs., 12 figs

  7. [Measurement of active particles generated in a coaxial barrier discharge by spectral method].

    Science.gov (United States)

    Li, Xue-Chen; Chang, Yuan-Yuan; Jia, Peng-Ying

    2013-05-01

    Coaxial dielectric barrier discharge has extensive application prospects. A dielectric barrier discharge device with water electrode was used to investigate the discharge properties and spectral intensity emitted from active particles in the air by optical method. Results indicate that the optical emission spectra consist of spectral lines from oxygen atoms (777.5 and 844.6 nm), which implies that oxygen atoms with high chemical activity were generated in the discharge plasma. Through spatially resolved measurements, spectral intensities from oxygen atoms were given as functions of the experimental parameters such as the value of the applied voltage, the gas flow rate and argon content. Results show that the spectral line intensity from oxygen atom increases with increasing the peak value of the applied voltage, increases with increasing the gas flow rate, reaches its maximum with a gas flow rate of 30 L x min(-1) and then decreases with further increasing the gas flow rate. Similarly, the spectral line intensity increases firstly and then decreases with increasing argon content (in a mixture of argon and air) and a maximum is reached when argon content is 16.7%. PMID:23905311

  8. Decontamination of airborne bacteria in meat processing plants

    Science.gov (United States)

    Air has been established as a source of bacterial contamination in meat processing facilities. Airborne bacteria may affect product shelf life, and have food safety implications. The effectiveness of reactive oxygen species (ROS) generating AirOcare equipment on the reduction of airborne bacteria in...

  9. Decontamination of airborne bacteria in meat processing plants

    Science.gov (United States)

    The effectiveness of reactive oxygen species (ROS) generating AirOcare equipment on the reduction of airborne bacteria in a meat processing environment was determined. Bacterial strains found in ground beef were used to artificially contaminate the air using a 6-jet Collison nebulizer. Airborne bact...

  10. Molecular composition and size distribution of sugars, sugar-alcohols and carboxylic acids in airborne particles during a severe urban haze event caused by wheat straw burning

    Science.gov (United States)

    Wang, Gehui; Chen, Chunlei; Li, Jianjun; Zhou, Bianhong; Xie, Mingjie; Hu, Shuyuan; Kawamura, Kimitaka; Chen, Yan

    2011-05-01

    Molecular compositions and size distributions of water-soluble organic compounds (WSOC, i.e., sugars, sugar-alcohols and carboxylic acids) in particles from urban air of Nanjing, China during a severe haze event caused by field burning of wheat straw were characterized and compared with those in the summer and autumn non-haze periods. During the haze event levoglucosan (4030 ng m -3) was the most abundant compound among the measured WSOC, followed by succinic acid, malic acid, glycerol, arabitol and glucose, being different from those in the non-haze samples, in which sucrose or azelaic acid showed a second highest concentration, although levoglucosan was the highest. The measured WSOC in the haze event were 2-20 times more than those in the non-hazy days. Size distribution results showed that there was no significant change in the compound peaks in coarse mode (>2.1 μm) with respect to the haze and non-haze samples, but a large difference in the fine fraction (glucose and related sugar-alcohols whose concentrations significantly increased in the fine haze samples are unclear. Compared to that in the fresh smoke particles of wheat straw burning an increase in relative abundance of succinic acid to levoglucosan during the haze event suggests a significant production of secondary organic aerosols during transport of the smoke plumes.

  11. Characterization of Cloud Water and Drop Residual Particle Properties in Northeastern Pacific Ocean Stratocumulus Clouds: Airborne Measurements during the E-PEACE 2012 Field Campaign

    Science.gov (United States)

    Sorooshian, A.; Wang, Z.; Coggon, M.; Craven, J. S.; Metcalf, A. R.; Lin, J. J.; Nenes, A.; Jonsson, H.; Flagan, R. C.; Seinfeld, J.

    2012-12-01

    During the July-August 2012 Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE), the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter carried out thirty flights off the California coast with a payload focused on detailed characterization of aerosol and cloud properties. A counter-flow virtual impactor (CVI) inlet was used in cloud to study the physical and chemical properties of drop residual particles in the climatically-important stratocumulus cloud deck over the northeastern Pacific Ocean. A total of 82 cloud water samples were also collected and examined with ion chromatography (17 anion species) and inductively coupled plasma mass spectrometry (> 50 elements). The pH of the cloud water samples ranged widely between 2.92 and 7.58. This work focuses on inter-relationships between the chemical signatures of cloud water and drop residual particles, in addition to the influence of numerous regional sources on these measurements. Of interest will be to look critically at the influence of biogenic oceanic sources, shipping traffic, and entrainment of free tropospheric aerosol.

  12. Quantification of organic content and coating on laboratory generated dust particles and their effect on ice nucleation processes

    Science.gov (United States)

    Mohr, Claudia; Saathoff, Harald; Möhler, Ottmar; Hiranuma, Naruki

    2015-04-01

    The ice nucleation efficiencies of various dust, mineral, and soot particles as a function of mineral composition, ambient temperature, freezing mode, and organic and sulfuric acid coating were investigated within the first part of the Fifth International Ice Nucleation Workshop (FIN-1) at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) chamber at the Karlsruhe Institute of Technology. A high-resolution time-of-flight aerosol mass spectrometer was used to quantify non-refractory components of particles with a vacuum aerodynamic diameter of up to 3 microns using a high-pressure aerodynamic lens. Measurements revealed that laboratory generated dust and mineral particles already contain an atmospherically relevant fraction of organic matter. For particles in the ~1 micron size range, the mass of this inherent organic fraction can correspond to that of several monolayers of organic molecules generated by ozonolysis of α-pinene. High-resolution analysis of organic mass spectra indicates differences in the composition of the inherent organic content and the organic coating added. Furthermore, changes in single particle morphology were observed with the onset of coating. We will present quantitative data of the inherent organic fraction for the different dust, mineral, and soot particles. We will discuss the importance of organic content and the effect of the additional organic coating as well as sulfuric acid coating for ice nucleation at various temperatures and freezing modes, and its implications for the real atmosphere.

  13. Thermal conductivity of U–Mo/Al dispersion fuel. Effects of particle shape and size, stereography, and heat generation

    International Nuclear Information System (INIS)

    This paper describes the effects of particle sphericity, interfacial thermal resistance, stereography, and heat generation on the thermal conductivity of U–Mo/Al dispersion fuel. The ABAQUS finite element method (FEM) tool was used to calculate the effective thermal conductivity of U–Mo/Al dispersion fuel by implementing fuel particles. For U–Mo/Al, the particle sphericity effect was insignificant. However, if the effect of the interfacial thermal resistance between the fuel particles and Al matrix was considered, the thermal conductivity of U–Mo/Al was increased as the particle size increases. To examine the effect of stereography, we compared the two-dimensional modeling and three-dimensional modeling. The results showed that the two-dimensional modeling predicted lower than the three-dimensional modeling. We also examined the effect of the presence of heat sources in the fuel particles and found a decrease in thermal conductivity of U–Mo/Al from that of the typical homogeneous heat generation modeling. (author)

  14. Promoting smoke-free homes: a novel behavioral intervention using real-time audio-visual feedback on airborne particle levels.

    Directory of Open Access Journals (Sweden)

    Neil E Klepeis

    Full Text Available Interventions are needed to protect the health of children who live with smokers. We pilot-tested a real-time intervention for promoting behavior change in homes that reduces second hand tobacco smoke (SHS levels. The intervention uses a monitor and feedback system to provide immediate auditory and visual signals triggered at defined thresholds of fine particle concentration. Dynamic graphs of real-time particle levels are also shown on a computer screen. We experimentally evaluated the system, field-tested it in homes with smokers, and conducted focus groups to obtain general opinions. Laboratory tests of the monitor demonstrated SHS sensitivity, stability, precision equivalent to at least 1 µg/m(3, and low noise. A linear relationship (R(2 = 0.98 was observed between the monitor and average SHS mass concentrations up to 150 µg/m(3. Focus groups and interviews with intervention participants showed in-home use to be acceptable and feasible. The intervention was evaluated in 3 homes with combined baseline and intervention periods lasting 9 to 15 full days. Two families modified their behavior by opening windows or doors, smoking outdoors, or smoking less. We observed evidence of lower SHS levels in these homes. The remaining household voiced reluctance to changing their smoking activity and did not exhibit lower SHS levels in main smoking areas or clear behavior change; however, family members expressed receptivity to smoking outdoors. This study established the feasibility of the real-time intervention, laying the groundwork for controlled trials with larger sample sizes. Visual and auditory cues may prompt family members to take immediate action to reduce SHS levels. Dynamic graphs of SHS levels may help families make decisions about specific mitigation approaches.

  15. Generation of IL-23 producing dendritic cells (DCs by airborne fungi regulates fungal pathogenicity via the induction of T(H-17 responses.

    Directory of Open Access Journals (Sweden)

    Georgios Chamilos

    Full Text Available Interleukin-17 (IL-17 producing T helper cells (T(H-17 comprise a newly recognized T cell subset with an emerging role in adaptive immunity to a variety of fungi. Whether different airborne fungi trigger a common signaling pathway for T(H-17 induction, and whether this ability is related to the inherent pathogenic behavior of each fungus is currently unknown. Here we show that, as opposed to primary pathogenic fungi (Histoplasma capsulatum, opportunistic fungal pathogens (Aspergillus and Rhizopus trigger a common innate sensing pathway in human dendritic cells (DCs that results in robust production of IL-23 and drives T(H-17 responses. This response requires activation of dectin-1 by the fungal cell wall polysaccharide b-glucan that is selectively exposed during the invasive growth of opportunistic fungi. Notably, unmasking of b-glucan in the cell wall of a mutant of Histoplasma not only abrogates the pathogenicity of this fungus, but also triggers the induction of IL-23 producing DCs. Thus, b-glucan exposure in the fungal cell wall is essential for the induction of IL-23/T(H-17 axis and may represent a key factor that regulates protective immunity to opportunistic but not pathogenic fungi.

  16. Airborne wind energy

    CERN Document Server

    Ahrens, Uwe; Schmehl, Roland

    2013-01-01

    This reference offers an overview of the field of airborne wind energy. As the first book of its kind, it provides a consistent compilation of the fundamental theories, a compendium of current research and development activities as well as economic and regulatory aspects. In five parts, the book demonstrates the relevance of Airborne Wind Energy and the role that this emerging field of technology can play for the transition towards a renewable energy economy. Part I on 'Fundamentals' contains seven general chapters explaining the principles of airborne wind energy and its different variants, o

  17. Particle Display: A Quantitative Screening Method for Generating High-Affinity Aptamers**

    OpenAIRE

    Wang, J.; Gong, Q; N Maheshwari; Eisenstein, M; Arcila, ML; Kosik, KS; Soh, HT

    2014-01-01

    We report an aptamer discovery technology that reproducibly yields higher affinity aptamers in fewer rounds compared to conventional selection. Our method (termed particle display) transforms libraries of solution-phase aptamers into "aptamer particles", each displaying many copies of a single sequence on its surface. We then use fluorescence-activated cell sorting (FACS) to individually measure the relative affinities of >108 aptamer particles and sort them in a high-throughput manner. Throu...

  18. Airborne plutonium-239 and americium-241 concentrations measured from the 125-meter Hanford Meteorological Tower

    International Nuclear Information System (INIS)

    Airborne plutonium-239 and americium-241 concentrations and fluxes were measured at six heights from 1.9 to 122 m on the Hanford meteorological tower. The data show that plutonium-239 was transported on nonrespirable and small particles at all heights. Airborne americium-241 concentrations on small particles were maximum at the 91 m height

  19. The International SubMillimetre Airborne Radiometer (ISMAR) - First results from the STICCS and COSMIC campaigns

    Science.gov (United States)

    Mendrok, Jana; Eriksson, Patrick; Fox, Stuart; Brath, Manfred; Buehler, Stefan

    2016-04-01

    Multispectral millimeter- and submillimeter-wave observations bear the potential to measure properties of non-thin ice clouds like mass content and mean particle size. The next generation of European meteorological satellites, the MetOp-SG series, will carry the first satellite-borne submillimeter sounder, the Ice Cloud Imager (ICI). An airborne demonstrator, the International SubMillimetre Airborne Radiometer (ISMAR), is operated together with other remote sensing instruments and in-situ probes on the FAAM aircraft. Scientific measurements from two campaings in the North Atlantic region, STICCS and COSMIC, are available so far. Here we will introduce the ISMAR instrument, present the acquired measurements from the STICCS and COSMIC campaigns and show some first results. This will include estimation of instrument performance, first analysis of clear-sky and cloudy cases and discussion of selected features observed in the measurements (e.g. polarisation signatures).

  20. Intermittent contact of fluidized anode particles containing exoelectrogenic biofilms for continuous power generation in microbial fuel cells

    KAUST Repository

    Liu, Jia

    2014-09-01

    Current generation in a microbial fuel cell can be limited by the amount of anode surface area available for biofilm formation, and slow substrate degradation kinetics. Increasing the anode surface area can increase the amount of biofilm, but performance will improve only if the anode material is located near the cathode to minimize solution internal resistance. Here we demonstrate that biofilms do not have to be in constant contact with the anode to produce current in an MFC. Granular activated carbon particles enriched with exoelectrogenic biofilm are fluidized (by stirring) in the anode chamber of the MFC, resulting in only intermittent contact between the particles and the anode current collector. The maximum power density generated is 951 ± 10 mW m-2, compared to 813 ± 2 mW m-2 for the control without stirring (packed bed), and 525 ± 1 mW m-2 in the absence of GAC particles and without stirring. GAC-biofilm particles demonstrate capacitor-like behavior, but achieve nearly constant discharge conditions due to the large number of particles that contact the current collector. These results provide proof of concept for the development of flowable electrode reactors, where anode biofilms can be electrically charged in a separate storage tank and then rapidly discharged in compact anode chambers. © 2014 Elsevier B.V. All rights reserved.

  1. Use of direct versus indirect preparation data for assessing risk associated with airborne exposures at asbestos-contaminated sites.

    Science.gov (United States)

    Goldade, Mary Patricia; O'Brien, Wendy Pott

    2014-01-01

    At asbestos-contaminated sites, exposure assessment requires measurement of airborne asbestos concentrations; however, the choice of preparation steps employed in the analysis has been debated vigorously among members of the asbestos exposure and risk assessment communities for many years. This study finds that the choice of preparation technique used in estimating airborne amphibole asbestos exposures for risk assessment is generally not a significant source of uncertainty. Conventionally, the indirect preparation method has been less preferred by some because it is purported to result in false elevations in airborne asbestos concentrations, when compared to direct analysis of air filters. However, airborne asbestos sampling in non-occupational settings is challenging because non-asbestos particles can interfere with the asbestos measurements, sometimes necessitating analysis via indirect preparation. To evaluate whether exposure concentrations derived from direct versus indirect preparation techniques differed significantly, paired measurements of airborne Libby-type amphibole, prepared using both techniques, were compared. For the evaluation, 31 paired direct and indirect preparations originating from the same air filters were analyzed for Libby-type amphibole using transmission electron microscopy. On average, the total Libby-type amphibole airborne exposure concentration was 3.3 times higher for indirect preparation analysis than for its paired direct preparation analysis (standard deviation = 4.1), a difference which is not statistically significant (p = 0.12, two-tailed, Wilcoxon signed rank test). The results suggest that the magnitude of the difference may be larger for shorter particles. Overall, neither preparation technique (direct or indirect) preferentially generates more precise and unbiased data for airborne Libby-type amphibole concentration estimates. The indirect preparation method is reasonable for estimating Libby-type amphibole exposure and

  2. The airborne laser

    Science.gov (United States)

    Lamberson, Steven; Schall, Harold; Shattuck, Paul

    2007-05-01

    The Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the current program status.

  3. Generation and characterization of nano tungsten oxide particles by wire explosion process

    International Nuclear Information System (INIS)

    Nano tungsten oxide particles are produced by wire explosion process. It is realized that by exploding tungsten conductor in lower pressure of oxygen, unreacted phase of tungsten was present and it could be reduced by increasing the operating pressure and increasing the amount of energy deposited to the exploding conductor. It is realized that the nucleation rate of the particle could be high only at the point of maximum saturation ratio, irrespective of the pressure of the oxygen. The size of the critical nucleus formed is low when the saturation ratio and the nucleation rate are at maximum. The nano metal oxide particle formation by wire explosion process allows one to conclude that the second stage annealing process has a major impact on the final grain size formed. The high speed camera photographs of wire explosion process were used to understand the dynamics of particle formation by wire explosion process. The Transmission Electron Microscopy (TEM) analysis indicates that the nano tungsten oxide (WO3) particles are of spherical shape and the analysis of particle size indicates that it follows log normal distribution. - Graphical Abstract: Nano tungsten oxide (WO3) particles are produced by wire explosion process. Theoretical analysis indicates that the size of the critical nucleus formed is low when the saturation ratio and the nucleation rate are at maximum. High speed camera photographs of wire explosion process were used to understand the dynamics of particles formed. Research Highlights: →Lower particle size is possible with lower pressure. →Particle size is increased with reduced energy ratio. →Unreacted tungsten content reduces when oxygen pressure increases.

  4. Traffic-generated emissions of ultrafine particles from pavement-tire interface

    Science.gov (United States)

    Dahl, Andreas; Gharibi, Arash; Swietlicki, Erik; Gudmundsson, Anders; Bohgard, Mats; Ljungman, Anders; Blomqvist, Göran; Gustafsson, Mats

    In a road simulator study, a significant source of sub-micrometer fine particles produced by the road-tire interface was observed. Since the particle size distribution and source strength is dependent on the type of tire used, it is likely that these particles largely originate from the tires, and not the road pavement. The particles consisted most likely of mineral oils from the softening filler and fragments of the carbon-reinforcing filler material (soot agglomerates). This identification was based on transmission electron microscopy studies of collected ultrafine wear particles and on-line thermal treatment using a thermodesorber. The mean particle number diameters were between 15-50 nm, similar to those found in light duty vehicle (LDV) tail-pipe exhaust. A simple box model approach was used to estimate emission factors in the size interval 15-700 nm. The emission factors increased with increasing vehicle speed, and varied between 3.7×10 11 and 3.2×10 12 particles vehicle -1 km -1 at speeds of 50 and 70 km h -1. This corresponds to between 0.1-1% of tail-pipe emissions in real-world emission studies at similar speeds from a fleet of LDV with 95% gasoline and 5% diesel-fueled cars. The emission factors for particles originating from the road-tire interface were, however, similar in magnitude to particle number emission factors from liquefied petroleum gas-powered vehicles derived in test bench studies in Australia 2005. Thus the road-tire interface may be a significant contributor to particle emissions from ultraclean vehicles.

  5. Short term hydroelectric power system scheduling with wind turbine generators using the multi-pass iteration particle swarm optimization approach

    International Nuclear Information System (INIS)

    This paper uses multi-pass iteration particle swarm optimization (MIPSO) to solve short term hydroelectric generation scheduling of a power system with wind turbine generators. MIPSO is a new algorithm for solving nonlinear optimal scheduling problems. A new index called iteration best (IB) is incorporated into particle swarm optimization (PSO) to improve solution quality. The concept of multi-pass dynamic programming is applied to modify PSO further and improve computation efficiency. The feasible operational regions of the hydro units and pumped storage plants over the whole scheduling time range must be determined before applying MIPSO to the problem. Wind turbine power generation then shaves the power system load curves. Next, MIPSO calculates hydroelectric generation scheduling. It begins with a coarse time stage and searching space and refines the time interval between two time stages and the search spacing pass by pass (iteration). With the cooperation of agents called particles, the near optimal solution of the scheduling problem can be effectively reached. The effects of wind speed uncertainty were also considered in this paper. The feasibility of the new algorithm is demonstrated by a numerical example, and MIPSO solution quality and computation efficiency are compared to those of other algorithms

  6. Dissolution and reactive oxygen species generation of inhaled cemented tungsten carbide particles in artificial human lung fluids

    International Nuclear Information System (INIS)

    Inhalation of both cobalt (Co) and tungsten carbide (WC) particles is associated with development of hard metal lung disease (HMD) via generation of reactive oxygen species (ROS), whereas Co alone is sufficient to cause asthma via solubilization and hapten formation. We characterized bulk and aerodynamically size-separated W, WC, Co, spray dryer (pre-sintered), and chamfer grinder (post-sintered) powders. ROS generation was measured in the murine RAW 264.7 cell line using electron spin resonance. When dose was normalized to surface area, hydroxyl radical generation was independent of particle size, which suggests that particle surface chemistry may be an important exposure factor. Chamfer grinder particles generated the highest levels of ROS, consistent with the hypothesis that intimate contact of metals is important for ROS generation. In artificial extracellular lung fluid, alkylbenzyldimethylammonium chloride (ABDC), added to prevent mold growth during experiments, did not influence dissolution of Co (44.0±5.2 vs. 48.3±6.4%); however, dissolution was higher (p<0.05) in the absence of phosphate (62.0±5.4 vs. 48.3±6.4%). In artificial macrophage phagolysosomal fluid, dissolution of Co (36.2±10.4%) does not appear to be influenced (p=0.30) by the absence of glycine (29.8±2.1%), phosphate (39.6±8.6%), or ABDC (44.0±10.5%). These results aid in assessing and understanding Co and W inhalation dosimetry.

  7. Characteristics of airborne gold aggregates generated by spark discharge and high temperature evaporation furnace: Mass-mobility relationship and surface area

    OpenAIRE

    Svensson, Christian; Ludvigsson, Linus; Meuller, Bengt; Eggersdorfer, M.L.; Deppert, Knut; Bohgard, Mats; Pagels, Joakim; Messing, Maria; Rissler, Jenny

    2015-01-01

    The properties of gas-borne aggregates are important in nano-technology and for potential health effects. Gold aggregates from three generators (one commercial and one custom built spark discharge generator and one high-temperature furnace) have been characterized. The aggregate surface areas were determined using five approaches - based on aggregation theory and/or measured aggregate properties. The characterization included mass-mobility relationships, effective densities (assessed by an Ae...

  8. Velocity Field of Particles Injected into Plasma Jet Generated by Torch with Water Stabilization

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan; Konrád, Miloš; Kopecký, Vladimír

    St. Petersburg : University St. Petersburg, 1998 - (Dresvin, S.), s. 130 [European Conference on Thermal Plasma Processes /5./. St. Petersburg (RU), 13.07.1998-16.07.1998] R&D Projects: GA AV ČR IAA1043804; GA ČR GA102/98/0813 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma-particle interaction, particle velocity, plasma jet Subject RIV: BL - Plasma and Gas Discharge Physics

  9. Momentum correlations of scattered particles in quantum field theory: one-loop entanglement generation

    CERN Document Server

    Faleiro, Ricardo; Alexander, Helder; Hiller, Brigitte; Blin, Alex; Sampaio, Marcos

    2016-01-01

    We compute the entanglement entropy variation between initial (separable or entangled in the momenta) and final states $\\Delta S_E$ in an elastic scattering of a bipartite system composed by two interacting scalar particles. We perform a quantum field theoretical calculation to one loop order and verify that $\\Delta S_E $ changes as we vary the energy of incoming particles and the coupling strength in a non-trivial way.

  10. Multiple-cylindrical Electrode System for Rotational Electric Field Generation in Particle Rotation Applications

    OpenAIRE

    Prateek Benhal; Geoffrey Chase, J.; Paul Gaynor; Björn Oback; Wenhui Wang

    2015-01-01

    Lab-on-a-chip micro-devices utilizing electric field-mediated particle movement provide advantages over current cell rotation techniques due to the flexibility in configuring micro-electrodes. Recent technological advances in micro-milling, three-dimensional (3D) printing and photolithography have facilitated fabrication of complex micro-electrode shapes. Using the finite-element method to simulate and optimize electric field induced particle movement systems can save time and cost by simplif...

  11. 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)

  12. A MODIFIED PARTICLE SWARM OPTIMIZATION TO SOLVE THE ECONOMIC DISPATCH PROBLEM OF THERMAL GENERATORS OF A POWER SYSTEM

    Directory of Open Access Journals (Sweden)

    M.Kondalu,

    2010-11-01

    Full Text Available The economic dispatch has the objective of generation allocation to the power generators in such a way that the total fuel cost is minimized while all operating constraints are satisfied. The schematic methods assume the cost curves of generators are linear but in case of modern generators this assumption makes inaccuracy in economic dispatch because of valve point loading effect, prohibited operating zone and ramp rate limits. By involving these three constraints the classical PSO faces premature convergence. To handle the problem of premature convergence this paper presents an efficient approach for solving nonconvex economic dispatch (NCED problem using a modified particle swarm optimization (MPSOcombined with roulette wheel selection method. The proposed method applied to six unit system having nonconvex solution spaces, and better results are obtained when compare with previous approach.

  13. AirborneWind Energy: Airfoil-Airmass Interaction

    OpenAIRE

    Zanon, Mario; Gros, Sebastien; Meyers, Johan; Diehl, Moritz

    2014-01-01

    The Airborne Wind Energy paradigm proposes to generate energy by flying a tethered airfoil across the wind flow at a high velocity. While Airborne Wind Energy enables flight in higher-altitude, stronger wind layers, the extra drag generated by the tether motion imposes a significant limit to the overall system efficiency. To address this issue, two airfoils with a shared tether can reduce overall system drag. A study proposed in Zanon et al. (2013) confirms this claim by showing that, in the ...

  14. Investigation of flow behind vortex generators by stereo particle image velocimetry on a thick airfoil near stall

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Hansen, Martin Otto Laver

    2013-01-01

    Stereoscopic Particle Image Velocimetry measurements investigating the effect of vortex generators (VGs) on the flow near stall were carried out in a purpose-built wind tunnel for airfoil investigations on a DU 91-W2-250 profile. Measurements were conducted at Re = 0.9⋅106, corresponding to free...... stream velocity U∞ = 15 m s−1. The objective was to investigate the flow structures induced by the vortex generators and study their separation controlling behavior on the airfoil. The uncontrolled flow (no VGs) displayed unsteady behavior with separation as observed from large streamwise velocity...

  15. Optimal reactive power and voltage control in distribution networks with distributed generators by fuzzy adaptive hybrid particle swarm optimisation method

    DEFF Research Database (Denmark)

    Chen, Shuheng; Hu, Weihao; Su, Chi;

    2015-01-01

    A new and efficient methodology for optimal reactive power and voltage control of distribution networks with distributed generators based on fuzzy adaptive hybrid PSO (FAHPSO) is proposed. The objective is to minimize comprehensive cost, consisting of power loss and operation cost of transformers...... and capacitors, and subject to constraints such as minimum and maximum reactive power limits of distributed generators, maximum deviation of bus voltages, maximum allowable daily switching operation number (MADSON). Particle swarm optimization (PSO) is used to solve the corresponding mixed integer non...

  16. Low pressure arc discharges with hollow cathodes and their using in plasma generators and charged particle sources

    CERN Document Server

    Vintizenko, L G; Koval, N N; Tolkachev, V S; Lopatin, I V; Shchanin, P M

    2001-01-01

    Paper presents the results of investigation into arc discharges with a hollow cathode generating 10 sup 1 sup 0 -10 sup 1 sup 2 concentration gas-discharge plasma in essential (approx 1 m sup 3) volumes at low (10 sup - sup 2 -1 Pa) pressures and up to 200 A discharge currents. One studied design of discharge systems with heated and cold cathodes their peculiar features, presented the parameters of plasma generators and of charged particle sources based on arc discharges and discussed, as well, the problems of more rational application of those systems in the processes for surface modification of solids

  17. Few-particles generation channels in inelastic hadron-nuclear interactions at energy approximately equals 400 GeV

    Science.gov (United States)

    Tsomaya, P. V.

    1985-01-01

    The behavior of the few-particles generation channels in interaction of hadrons with nuclei of CH2, Al, Cu and Pb at mean energy 400 GeV was investigated. The values of coherent production cross-sections beta coh at the investigated nuclei are given. A dependence of coherent and noncoherent events is investigated. The results are compared with the simulations on additive quark model (AQM).

  18. Principle Optimal Placement and Sizing of Single Distributed Generation for Power Loss Reduction using Particle Swarm Optimization

    OpenAIRE

    Krischonme Bhumkittipich

    2014-01-01

    This study presents a methodology using Particle Swarm Optimization (PSO) for the placement of single Distributed Generation (DG) in the radial distribution systems to reduce the power loss. The single DG placement is used to find the optimal DG location and sizing which is corresponded to the maximum power loss reduction. The proposed method is tested on the 26-bus radial power distribution system which modified from the Provincial Electricity Authority system in Thailand. The load flow anal...

  19. Advanced Penning-type ion source development and passive beam focusing techniques for an associated particle imaging neutron generator

    OpenAIRE

    Sy, Amy

    2013-01-01

    The use of accelerator-based neutron generators for non-destructive imaging and analysis in commercial and security applications is continuously under development, with improvements to available systems and combinations of available techniques revealing new capabilities for real-time elemental and isotopic analysis. The recent application of associated particle imaging (API) techniques for time- and directionally-tagged neutrons to induced fission and transmission imaging methods demonstrate...

  20. Size-dependent hydroxyl radicals generation induced by SiO2 ultra-fine particles: The role of surface iron

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM10). The ultra-fine fraction of PM10 has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2 particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2 particles with diameters of 14, 100, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 14 nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2 = 0.812, p<0.01). Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2 particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2 acted as an inert substrate, and the surface of ultra-fine SiO2 particles acted as a carrier for iron.

  1. Generation and evolution of nanoscale AlP and Al13Fe4 particles in Al-Fe-P system

    International Nuclear Information System (INIS)

    Highlights: • Diffusion and gradual solid reactions between Al and FexP phases in Al-Fe-P alloy were investigated. • Nanoscale AlP clusters are in-situ generated and evolve during the whole process. • This novel Al-Fe-P alloy has an excellent low-temperature refining performance on hypereutectic Al-Si alloy. - Abstract: In this paper, the gradual solid reactions between Al and FexP phases in Al-Fe-P alloy were investigated. The results show that the whole reaction process undergoes four main stages: the diffusion of Al atom, the generation of (Al, Fe, P) intermediate compound, the precipitation of nano AlP and Al13Fe4 clusters and their growth to submicron particles. The microstructure of Fe-P particles evolves from the “egg-type”, the “sponge-type” to the “sesame-cake” structure. AlP and Al13Fe4 nano phases have in-situ generated and evolved during the whole process. The gradual reaction mechanism has been discussed. Furthermore, a novel Al-Fe-P alloy which contains (Al, Fe, P) intermediate compounds and nano AlP particles has been synthesized and its low-temperature refining performance on A390 alloy has also been investigated

  2. Particle-In-Cell (PIC) code simulation results and comparison with theory scaling laws for photoelectron-generated radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dipp, T.M. [Los Alamos National Lab., NM (United States)]|[Air Force Office of Scientific Research, Bolling AFB, DC (United States)

    1993-12-01

    The generation of radiation via photoelectrons induced off of a conducting surface was explored using Particle-In-Cell (PIC) code computer simulations. Using the MAGIC PIC code, the simulations were performed in one dimension to handle the diverse scale lengths of the particles and fields in the problem. The simulations involved monoenergetic, nonrelativistic photoelectrons emitted normal to the illuminated conducting surface. A sinusoidal, 100% modulated, 6.3263 ns pulse train, as well as unmodulated emission, were used to explore the behavior of the particles, fields, and generated radiation. A special postprocessor was written to convert the PIC code simulated electron sheath into far-field radiation parameters by means of rigorous retarded time calculations. The results of the small-spot PIC simulations were used to generate various graphs showing resonance and nonresonance radiation quantities such as radiated lobe patterns, frequency, and power. A database of PIC simulation results was created and, using a nonlinear curve-fitting program, compared with theoretical scaling laws. Overall, the small-spot behavior predicted by the theoretical scaling laws was generally observed in the PIC simulation data, providing confidence in both the theoretical scaling laws and the PIC simulations.

  3. Assessing deposition of airborne particulates and gases in the Selkirk area using lichens growing on tree trunks : non-technical summary

    International Nuclear Information System (INIS)

    An independent study was conducted to address the public concern regarding airborne emissions from Manitoba Hydro's coal-fired electricity generating station located in the Selkirk area. This document is a non-technical summary of the report issued by Ecostem Ltd. Since there are no air quality monitoring stations in the study area which covers more than 1,000 square km, Ecostem used lichens as biological indicators of historical deposition of airborne dust and gases. The sources of airborne dust and gases include urban centres, agriculture, pesticides, fertilizers, waste burning, vehicle use and manufacturing. Lichens have been commonly used as indicators since 1866. They provide useful information because they are long-lived, are not mobile, acquire most of their nutrients from the atmosphere, retain the airborne deposition they initially trap, and they can accumulate airborne particles year round. It is possible to obtain a record of the chemicals that have been present in the air by simply analyzing the lichen tissue. This study used the concentrations of various chemical elements in lichen tissue and the distribution and abundance of lichen species to see if airborne particulates were substantially elevated in the Selkirk area and if so, to determine if the coal-fired generating station was the apparent source of the pollution. A total of 62 stations and lichens on more than 400 trees were sampled. Sulphur, a fingerprint for gaseous emissions from the generating station, had tissue concentrations that were 1.32 times higher. Statistical analysis suggests that barium, boron and strontium were the clearest fingerprint elements for generating station emissions. Tissue concentrations of antimony, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, molybdenum, nickel, selenium, silver, thallium, tin, vanadium and zinc were examined further because they are considered to be toxic. It was noted that a conclusion regarding human health cannot be made

  4. Wavelet Based Fractal Analysis of Airborne Pollen

    OpenAIRE

    Degaudenzi, M. E.; Arizmendi, C. M.

    1998-01-01

    The most abundant biological particles in the atmosphere are pollen grains and spores. Self protection of pollen allergy is possible through the information of future pollen contents in the air. In spite of the importance of airborne pol len concentration forecasting, it has not been possible to predict the pollen concentrations with great accuracy, and about 25% of the daily pollen forecasts have resulted in failures. Previous analysis of the dynamic characteristics of atmospheric pollen tim...

  5. Development of an expert system for automatic mesh generation for S(N) particle transport method in parallel environment

    Science.gov (United States)

    Patchimpattapong, Apisit

    This dissertation develops an expert system for generating an effective spatial mesh distribution for the discrete ordinates particle transport method in a parallel environment. This expert system consists of two main parts: (1) an algorithm for generating an effective mesh distribution in a serial environment, and (2) an algorithm for inference of an effective domain decomposition strategy for parallel computing. The mesh generation algorithm consists of four steps: creation of a geometric model as partitioned into coarse meshes, determination of an approximate flux shape, selection of appropriate differencing schemes, and generation of an effective fine mesh distribution. A geometric model was created using AutoCAD. A parallel code PENFC (Parallel Environment Neutral-Particle First Collision) has been developed to calculate an uncollided flux in a 3-D Cartesian geometry. The appropriate differencing schemes were selected based on the uncollided flux distribution using a least squares methodology. A menu-driven serial code PENXMSH has been developed to generate an effective spatial mesh distribution that preserves problem geometry and physics. The domain decomposition selection process involves evaluation of the four factors that affect parallel performance, which include number of processors and memory available per processor, load balance, granularity, and degree-of-coupling among processors. These factors are used to derive a parallel-performance-index that provides expected performance of a parallel algorithm depending on computing environment and resources. A large index indicates a high granularity algorithm with relatively low coupling among processors. This expert system has been successfully tested within the PENTRAN (Parallel Environment Neutral-Particle Transport) code system for simulating real-life shielding problems: the VENUS-3 experimental facility and the BWR core shroud.

  6. Characteristics of a RF-Driven Ion Source for a Neutron Generator Used For Associated Particle Imaging

    International Nuclear Information System (INIS)

    We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T,n)4 alpha) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 muA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80percent can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed.

  7. Characteristics of a RF-Driven Ion Source for a Neutron Generator Used For Associated Particle Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ying; Hurley, John P.; Ji, Qing; Kwan, Joe; Leung, Ka-Ngo

    2008-08-08

    We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T,n)4 alpha) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 muA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80percent can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed.

  8. Localization of two-particle quantum walk on glued-tree and its application in generating Bell states

    Science.gov (United States)

    Wang, Huiquan; Wu, Junjie; He, Hongjuan; Tang, Yuhua

    2016-08-01

    Studies on two-particle quantum walks show that the spatial interaction between walkers will dynamically generate complex entanglement. However, those entanglement states are usually on a large state space and their evolutions are complex. It makes the entanglement states generated by quantum walk difficult to be applied directly in many applications of quantum information, such as quantum teleportation and quantum cryptography. In this paper, we firstly analyse a localization phenomena of two-particle quantum walk and then introduce how to use it to generate a Bell state. We will show that one special superposition component of the walkers' state is localized on the root vertex if a certain interaction exists between walkers. This localization is interesting because it is contrary to our knowledge that quantum walk spreads faster than its classical counterpart. More interestingly, the localized component is a Bell state in the coin space of two walkers. By this method, we can obtain a Bell state easily from the quantum walk with spatial interaction by a local measurement, which is required in many applications. Through simulations, we verify that this method is able to generate the Bell state 1/√{2}(|A rangle _1|Arangle _2 ± |Brangle _1|Brangle _2) in the coin space of two walkers with fidelity greater than 99.99999 % in theory, and we have at least a 50 % probability to obtain the expected Bell state after a proper local measurement.

  9. Combustion of PTFE: The effects of gravity on ultrafine particle generation

    Science.gov (United States)

    McKinnon, Thomas; Todd, Paul; Oberdorster, Gunter

    1996-01-01

    The objective of this project is to obtain an understanding of the effect of gravity on the toxicity of ultrafine particle and gas phase materials produced when fluorocarbon polymers are thermally degraded or burned. The motivation for the project is to provide a basic technical foundation on which policies for spacecraft health and safety with regard to fire and polymers can be formulated.

  10. Particle velocity generated by rockburst during exploitation of the longwall and its impact on the workings

    Czech Academy of Sciences Publication Activity Database

    Holub, Karel; Rušajová, Jana; Holečko, J.

    2011-01-01

    Roč. 48, č. 6 (2011), s. 942-949. ISSN 1365-1609 Institutional research plan: CEZ:AV0Z30860518 Keywords : Ostrava-Karviná Coal Basin * rockburst * particle velocity * working damage Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.272, year: 2011 http://www. science direct.com/ science /article/pii/S1365160911000876

  11. Second harmonic generation from small gold metallic particles: from the dipolar to the quadrupolar response.

    Science.gov (United States)

    Nappa, J; Russier-Antoine, I; Benichou, E; Jonin, Ch; Brevet, P F

    2006-11-14

    Hyper Raleigh scattering, a common technique to investigate the second harmonic light scattered from a liquid suspension of molecular compounds and to determine their quadratic hyperpolarizability, has been used for aqueous suspensions of gold nanoparticles, the diameter of which ranges from 20 up to 150 nm. The hyper Rayleigh signal intensity was recorded as a function of the angle of polarization of the incident fundamental wave. For the particles with a diameter smaller than 50 nm, the response is dominated by the dipolar contribution arising from the deviation of the particle shape from that of a perfect sphere. For larger diameter particles, retardation effects in the interaction of the electromagnetic fields with the particles cannot be neglected any longer and the response deviates from the pure dipolar response, exhibiting a strong quadrupolar contribution. It is then shown that in order to quantify the relative magnitude of these two dipolar and quadrupolar contributions, a weighting parameter zeta(V) which equals unity for a pure quadrupolar contribution and vanishes for a pure dipolar response, can be introduced. PMID:17115784

  12. Effect of Generation of Charged Particles Fluxes by Pulsed Gas Discharge

    CERN Document Server

    Pozdnyakov, Georgiy A

    2014-01-01

    The paper describes the effect of generation of electron and ion fluxes in a gas discharge, which offers, in particular, to the emergence of "blue jets" and "elves", observed during thunderstorms. An experimental facility modeling these phenomena is described. A possibility of generation of strong-current fluxes of electrons and ions in a straightline gas electric discharge is demonstrated.

  13. Generation of sub-micron particles and secondary pollutants from building materials by ozone reaction

    Science.gov (United States)

    Aoki, Taisuke; Tanabe, Shin-ichi

    This study reports results from two different experiments examining reactions between ozone and common building materials that can lead to the formation of secondary products and particulate-phase materials. Monitored species include sub-micron particles and volatile organic compounds (VOCs). In the first set of experiments, various building materials were placed in a 20 L stainless-steel chamber and exposed to ozone. The materials included expanded polystyrene, a natural rubber adhesive, cedar board, Japanese Cyprus board and silver fir board, as well as d-limonene, which is a known constituent of certain woods and cleaning products. The combination of ozone and either d-limonene, cedar board or cypress board produced sub-micron particles, with most of the increase occurring in the size range of 0.01- 0.5μm diameter. This was not observed for the other materials. In the case of cedar board, the consequence of ozone exposure over an extended time interval was monitored. As the exposure time elapsed, the concentration of sub-micron particles moderately decreased. In the second set of experiments, unwaxed or waxed plastic tiles were placed in the 20 L chamber and exposed to ozone. Sub-micron particles and organic compounds were measured during the course of the experiments. In the case of the waxed tile, the number of 0.01- 1.0μm size particles grew about 50×108particlesm-3; particle growth was significantly less for the un-waxed tile. For both the waxed and un-waxed tiles, the emission rates of heptane, nonane, nonanal, and decanal increased after ozone was added to the supply air. (However, it is not clear if some or all of this production was due to ozone reacting with the sorbent used for sampling or with compounds captured by the sorbent.) This study provides further evidence that ozone-initiated reactions with building materials can be a significant source of both sub-micron particles and secondary organic compounds in indoor environments.

  14. Production of Novel Ebola Virus-Like Particles from cDNAs: an Alternative to Ebola Virus Generation by Reverse Genetics

    OpenAIRE

    Watanabe, Shinji; Watanabe, Tokiko; Noda, Takeshi; Takada, Ayato; Feldmann, Heinz; Jasenosky, Luke D.; Kawaoka, Yoshihiro

    2004-01-01

    We established a plasmid-based system for generating infectious Ebola virus-like particles (VLPs), which contain an Ebola virus-like minigenome consisting of a negative-sense copy of the green fluorescent protein gene. This system produced nearly 103 infectious particles per ml of supernatant, equivalent to the titer of Ebola virus generated by a reverse genetics system. Interestingly, infectious Ebola VLPs were generated, even without expression of VP24. Transmission and scanning electron mi...

  15. Optimal Placement and Sizing of Capacitor and Distributed Generation with Harmonic and Resonance Considerations Using Discrete Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    M. Heydari

    2013-06-01

    Full Text Available Presence of distributed generation (DG in distribution systems has significant impacts on the operational characteristics of these systems, also using capacitor for reactive compensation and loss reduction is so common. Injected harmonic currents from non-linear loads into distribution system distort all of voltages and currents and must be considered when placing the capacitor banks so that the resonance will not occur. In this paper discrete particle swarm optimization (DPSO approach is used for the optimal placement and sizing of distributed generations and capacitors in distribution systems for simultaneous voltage profile improvement, loss and total harmonic distortion (THD reduction. There is a term in the objective function which prevents harmonic resonance between capacitor reactance and system reactance. Constraints include voltage limit, voltage THD, number/ size of capacitors and generators. For evaluating the proposed algorithm, the IEEE 33-bus test system is modified and employed.

  16. Kinetic evaluation of new generation of column packed with 1.3 μm core-shell particles.

    Science.gov (United States)

    Fekete, Szabolcs; Guillarme, Davy

    2013-09-20

    The goal of this study was to critically evaluate a new generation of columns packed with 1.3 μm core-shell particles. The practical possibilities and limitations of this column technology were assessed and performance was compared with other reference columns packed with 1.7, 2.6 and 5 μm core-shell particles. The column efficiency achieved with 1.3 μm core-shell particles was indeed impressive, Hmin value of only 1.95 μm was achieved, this would correspond to an efficiency of more than 500,000 plates/m. The separation impedance of this column was particularly low, Emin=2000, mostly due to a reduced plate height, h of 1.50. Comparing the kinetic performance of 1.3 μm core-shell particles to that of other particle dimensions tested in this study revealed that the 1.3 μm material could provide systematically the shortest analysis time in a range of below 30,000 theoretical plates (Nlimitations of current instrumentation in terms of upper pressure limit and extra-column band broadening: (1) even at 1,200 bar, it was not possible to reach an optimal linear velocity showing minimal plate height value, due to the low permeability of this column (Kv=1.7×10(-11)cm(2)), and (2) for these short narrow bore columns packed with 1.3 μm core shell particles, which is mandatory for performing fast-analysis and preventing the influence of frictional heat on column performance in UHPLC, it was observed that the extra-column band broadening could have a major impact on the apparent kinetic performance. In the present work, significant plate count loss was noticed for retention factors of less than 5, even with the best system on the market (σ(2)ec=2 μL(2)). PMID:23953620

  17. Visible light-driven photocatalytic H2-generation activity of CuS/ZnS composite particles

    International Nuclear Information System (INIS)

    Highlights: • Preparation of CuS/ZnS composite photocatalyst by cation-exchange reaction. • Visible light photocatalytic activity for H2 evolution without cocatalyst. • The H2-evolution rate from water splitting depends on the CuS content. • The highest rate of H2 evolution is obtained with CuS (0.5 mol%)/ZnS composite. - Abstract: CuS/ZnS composite particles with diameter of 200–400 nm were successfully prepared by a simple cation-exchange reaction using ZnS spheres as a precursor. CuS nanoparticles with a few nanometers in diameter were observed on the surface of composite particles. The synthesized CuS/ZnS composite particles showed photocatalytic property effective for H2 evolution from an aqueous Na2S and Na2SO3 solution under visible light irradiation without any cocatalysts. The rate of H2 generation was found to be strongly dependent on the CuS content. The highest rate of H2 evolution reached 695.7 μmol h−1 g−1, which was almost 7 times as high as that of the mechanical mixture of CuS and ZnS. The enhancement in the photocatalytic activity of CuS/ZnS composite particles is supposed to be due to the direct interfacial charge transfer of the CuS/ZnS heterojunction

  18. Airborne fourier infrared spectrometer system

    International Nuclear Information System (INIS)

    A commercial Fourier Transform Infrared (FTIR) spectrometer has been interfaced to a 35 cm aperture telescope and a digital data processing and display system and flown in a downward-viewing configuration on a Queen Air aircraft. Real-time spectral analysis and display software were developed to provide the means to direct aircraft flight operations based on atmospheric and/or surface features identified on 1 to 8 cm-1 resolution infrared spectra. Data are presented from ground-based tests consisting of simultaneous horizontal path measurements by the FTIR system and an infrared differential absorption lidar (DIAL) observing gas volumes generated in an open-ended chamber. Airborne FUR data are presented on the tracking of a surface-released puff of SF6 gas to a downwind distance of 45 km in a time period of 1.5 hours. The experiment demonstrated the real time tracking of a gas tracer cloud to provide atmospheric transport and diffusion information and for directing airborne in-situ sensors for optimum cloud sampling. 5 refs., 5 figs

  19. Transfer of suspended particles from liquid effluents of nuclear generating stations through the environment

    International Nuclear Information System (INIS)

    Due to the complexity of the environmental transfer of suspended particles in aquatic systems, the available literature usually deals with specific pathways and mechanisms of the transfer process. This paper attempts to give a brief overview of the entire transfer process. Potential routes of transfer in both the marine and freshwater environments are examined, and tentative conclusions presented. This work was performed while the author was employed by Atomic Energy Control Board under the McMaster University cooperative program

  20. Characterization of Particle Size Distributions of Powdery Building Material Aerosol Generated by Fluidization and Gravitation

    Directory of Open Access Journals (Sweden)

    Tadas Prasauskas

    2012-10-01

    Full Text Available This study aims to identify particle size distributions (PSD of aerosol of powdery building materials commonly used in construction work (cement, chalk, clay, wood sawdust, wood grinding dust, gypsum, hydrated lime, masonry grout, quartz sand, sand and structural lime by two aerosolization methods: fluidization and gravitation. Fluidization and gravitation methods represent industrial activities such as pneumotransportation and unloading. Both particle resuspension mechanisms have been modelled in laboratory conditions. The particle size distributions of resuspended particulate matter from powdery building materials were rather similar identified by both fluidization and gravitation methods, with an exception of wood sawdust and sand. The PM10 fraction ranged between 30% and 87%, PM2.5 from 7% to 28% and PM1.0 from 3% to 7% of the total mass of particulate matter. The highest PM10/PMtotal ratio was calculated for masonry grout - 0.87, and the lowest ratio for quartz sand - 0.30. The highest ratio of PM2.5/PMtotal was calculated for sand - 0.23, the lowest for quartz sand - 0.07. Substantial quantities of PM2.5 were found to be emitted implying a potential threat to human health.DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1519

  1. Multiple-cylindrical Electrode System for Rotational Electric Field Generation in Particle Rotation Applications

    Directory of Open Access Journals (Sweden)

    Prateek Benhal

    2015-07-01

    Full Text Available Lab-on-a-chip micro-devices utilizing electric field-mediated particle movement provide advantages over current cell rotation techniques due to the flexibility in configuring micro-electrodes. Recent technological advances in micro-milling, three-dimensional (3D printing and photolithography have facilitated fabrication of complex micro-electrode shapes. Using the finite-element method to simulate and optimize electric field induced particle movement systems can save time and cost by simplifying the analysis of electric fields within complex 3D structures. Here we investigated different 3D electrode structures to obtain and analyse rotational electric field vectors. Finite-element analysis was conducted by an electric current stationary solver based on charge relaxation theory. High-resolution data were obtained for three-, four-, six- and eight-cylindrical electrode arrangements to characterize the rotational fields. The results show that increasing the number of electrodes within a fixed circular boundary provides larger regions of constant amplitude rotational electric field. This is a very important finding in practice, as larger rotational regions with constant electric field amplitude make placement of cells into these regions, where cell rotation occurs, a simple task – enhancing flexibility in cell manipulation. Rotation of biological particles over the extended region would be useful for biotechnology applications which require guiding cells to a desired location, such as automation of nuclear transfer cloning.

  2. The Virtual Resistance Control Strategy for HVRT of Doubly Fed Induction Wind Generators Based on Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Zhen Xie

    2014-01-01

    Full Text Available Grid voltage swell will cause transient DC flux component in the doubly fed induction generator (DFIG stator windings, creating serious stator and rotor current and torque oscillation, which is more serious than influence of the voltage dip. It is found that virtual resistance manages effectively to suppress rotor current and torque oscillation, avoid the operation of crowbar circuit, and enhance its high voltage ride through technology capability. In order to acquire the best virtual resistance value, the excellent particle library (EPL of dynamic particle swarm optimization (PSO algorithm is proposed. It takes the rotor voltage and rotor current as two objectives, which has a fast convergence performance and high accuracy. Simulation and experimental results verify the effectiveness of the virtual resistance control strategy.

  3. Second harmonic generation response by gold nanoparticles at the polarized water/2-octanone interface: from dispersed to aggregated particles

    Energy Technology Data Exchange (ETDEWEB)

    Galletto, P [Laboratoire d' Electrochimie Physique et Analytique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Girault, H H [Laboratoire d' Electrochimie Physique et Analytique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Gomis-Bas, C [Centre for Nanoscale Science, Department of Chemistry, University of Liverpool, Liverpool L69 3BX (United Kingdom); Schiffrin, D J [Centre for Nanoscale Science, Department of Chemistry, University of Liverpool, Liverpool L69 3BX (United Kingdom); Antoine, R [Universite Lyon 1, Laboratoire de Spectrometrie Ionique et Moleculaire, UMR CNRS 5579, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France); Broyer, M [Universite Lyon 1, Laboratoire de Spectrometrie Ionique et Moleculaire, UMR CNRS 5579, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France); Brevet, P F [Universite Lyon 1, Laboratoire de Spectrometrie Ionique et Moleculaire, UMR CNRS 5579, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France)

    2007-09-19

    Gold nanoparticles with a diameter of approximately 20 nm have been observed at the polarized water/2-octanone interface by the nonlinear optical technique of second harmonic generation. Electric field induced adsorption of the gold particles at this liquid/liquid interface is clearly observed and confirms that these are negatively charged. The process is quasi-reversible at high potential sweep rates, but aggregation at the interface is observed at slower sweep rates through the loss of the nonlinear optical signal. The time evolution of the second harmonic signal is also reported during potential step experiments. After a rapid increase due to adsorption, a continuous decrease in the nonlinear optical signal intensity is observed due to aggregation of the particles into large islands at the interface. Diffusion of these large islands at the interface was observed for a longer timescale through large signal fluctuations.

  4. Microwaves in Airborne Surveillance

    Directory of Open Access Journals (Sweden)

    S. Christopher

    2013-03-01

    Full Text Available The use of microwave spectrum is widespread due to its convenience. Therefore, enormous amount of information is available in the free space channel. Obviously, mining this channel for surveillance is quite common. Airborne surveillance offers significant advantages in military operations. This paper talks of the usage of microwaves in airborne surveillance systems, in general, and in the Indian airborne early warning and control (AEW&C System, in particular. It brings out the multiple sub-systems onboard the aircraft comprising the AEW&C system and their spectral coverage. Co-location of several systems has its own problems and resolving them in terms of geometric location, frequency band and time of operation are covered. AEW&C, being an airborne system, has several other requirements  including minimal weight, volume and power considerations, lightning protection, streamlining, structural integrity, thermal management, vibration tolerance, corrosion prevention, erosion resistance, static charge discharge capability, bird strike resilience, etc. The methods adopted to cater to all these requirements in the microwave systems that are used in the AEW&C system are discussed. Paper ultimately speaks of the microwave systems that are designed and developed for the Indian AEW&C system to surmount these unusual constraints.Defence Science Journal, 2013, 63(2, pp.138-144, DOI:http://dx.doi.org/10.14429/dsj.63.4255

  5. Effect of an Air Cleaner with Electrostatic Filter on the Removal of Airborne House Dust Mite Allergens

    OpenAIRE

    Agrawal, Santosh Rani; Kim, Hak-Joon; Lee, Yong Won; Sohn, Jung-Ho; Lee, Jae Hyun; Kim, Yong-Jin; Lee, Sung-Hwa; Hong, Chein-Soo; Park, Jung-Won

    2010-01-01

    Purpose The effects of air cleaners on the removal of airborne indoor allergens, especially house dust mites (HDM), are still controversial. The objective of this study is to evaluate the effect of an air cleaner with an electrostatic filter on the removal of airborne mite allergens. Materials and Methods A dried HDM culture medium that contained mite body particles and excretions was dispersed in a chamber equipped with an electrostatic air cleaner. The number of airborne particles was recor...

  6. International Symposium on Airborne Geophysics

    Science.gov (United States)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  7. Development and calibration of real-time PCR for quantification of airborne microorganisms in air samples

    Science.gov (United States)

    An, Hey Reoun; Mainelis, Gediminas; White, Lori

    This manuscript describes the coupling of bioaerosol collection and the use of real-time PCR (RT-PCR) to quantify the airborne bacteria. The quantity of collected bacteria determined by RT-PCR is compared with conventional quantification techniques, such as culturing, microscopy and airborne microorganism counting by using optical particle counter (OPC). Our data show that an experimental approach used to develop standard curves for use with RT-PCR is critical for accurate sample quantification. Using universal primers we generated 12 different standard curves which were used to quantify model organism Escherichia coli (Migula) Catellani from air samples. Standard curves prepared using a traditional approach, where serially diluted genomic DNA extracted from pure cultured bacteria were used in PCR reaction as a template DNA yielded significant underestimation of sample quantities compared to airborne microorganism concentration as measured by an OPC. The underestimation was especially pronounced when standard curves were built using colony forming units (CFUs). In contrast, the estimate of cell concentration in an air sample by RT-PCR was more accurate (˜60% compared to the airborne microorganism concentration) when the standard curve was built using aerosolized E. coli. The accuracy improved even further (˜100%) when air samples used to build the standard curves were diluted first, then the DNA extracted from each dilution was amplified by the RT-PCR—to mimic the handling of air samples with unknown and possibly low concentration. Therefore, our data show that standard curves used for quantification by RT-PCR needs to be prepared using the same environmental matrix and procedures as handling of the environmental sample in question. Reliance on the standard curves generated with cultured bacterial suspension (a traditional approach) may lead to substantial underestimation of microorganism quantities in environmental samples.

  8. The United States Particle Accelerator School: Educating the next generation of accelerator scientists and engineers

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, William A.; /MIT

    2008-09-01

    Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator / beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, crossdisciplinary research areas such as high energy density physics.

  9. Three-dimensional arrays of submicron particles generated by a four-beam optical lattice.

    Science.gov (United States)

    Slama-Eliau, B N; Raithel, G

    2011-05-01

    Using an optical lattice formed by four laser beams, we obtain three-dimensional light-induced crystals of 490-nm-diameter polystyrene spheres in solution. The setup yields face-centered orthorhombic optical crystals of a packing density of about 40%. An alignment procedure is developed in which the crystals are first prepared near a sample wall, and then in the bulk of the sample. A series of tests is performed that demonstrate particle trapping in all three dimensions. For one case, the trapping force is measured, and good agreement with a simple theoretical model is found. Possible applications are discussed. PMID:21728533

  10. The United States Particle Accelerator School: Educating the Next Generation of Accelerator Scientists and Engineers

    Science.gov (United States)

    Barletta, William A.

    2009-03-01

    Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator/beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, cross-disciplinary research areas such as high energy density physics.

  11. The United States Particle Accelerator School: Educating the Next Generation of Accelerator Scientists and Engineers

    International Nuclear Information System (INIS)

    Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator/beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, cross-disciplinary research areas such as high energy density physics.

  12. Perspectives on Entangled Nuclear Particle Pairs Generation and Manipulation in Quantum Communication and Cryptography Systems

    Directory of Open Access Journals (Sweden)

    Octavian Dănilă

    2012-01-01

    Full Text Available Entanglement between two quantum elements is a phenomenon which presents a broad application spectrum, being used largely in quantum cryptography schemes and in physical characterisation of the universe. Commonly known entangled states have been obtained with photons and electrons, but other quantum elements such as quarks, leptons, and neutrinos have shown their informational potential. In this paper, we present the perspective of exploiting the phenomenon of entanglement that appears in nuclear particle interactions as a resource for quantum key distribution protocols.

  13. Reducing field emission in the superconducting rf cavities for the next generation of particle accelerators

    International Nuclear Information System (INIS)

    This paper reports on field emission, which is an obstacle to reaching the higher fields called for in future applications of superconducting radio frequency cavities to particle accelerators. The authors used heat treatment up to 1500 degrees C in an ultra-high vacuum furnace, along with processing of cavities and temperature mapping, to suppress field emission and analyze emitter properties. In 27 tests of 1-cell 1500 MHz fired accelerating cavities, on the average the accelerating field Eacc increased to 24 MV/m (Hpk = 1250 Oe) from 13 MV/m with chemical treatment alone; the highest Eacc reached was 30.5 MV/m

  14. Endotoxin in Size-Separated Metal Working Fluid Aerosol Particles.

    Science.gov (United States)

    Dahlman-Höglund, Anna; Lindgren, Åsa; Mattsby-Baltzer, Inger

    2016-08-01

    Patients with airway symptoms working in metal working industries are increasing, despite efforts to improve the environmental air surrounding the machines. Our aim was to analyse the amount of endotoxin in size-separated airborne particles of metal working fluid (MWF) aerosol, by using the personal sampler Sioutas cascade impactor, to compare filter types, and to compare the concentration of airborne endotoxin to that of the corresponding MWFs. In a pilot field study, aerosols were collected in two separate machine halls on totally 10 occasions, using glass fibre and polytetrafluoroethylene (PTFE) filters in parallel at each station. Airborne endotoxin was distributed over all size fractions. While a major part was found in the largest size fraction (72%, 2.5-10 µm), up to 8% of the airborne endotoxin was detected in the smallest size fraction (efficiency of the filter types, a significantly higher median endotoxin level was found with glass fibres filters collecting the largest particle-size fraction (1.2-fold) and with PTFE filters collecting the smallest ones (5-fold). The levels of endotoxin in the size-separated airborne particle fractions correlated to those of the MWFs supporting the aerosol-generating machines. Our study indicates that a significant part of inhalable aerosols of MWFs consists of endotoxin-containing particles below the size of intact bacteria, and thus small enough to readily reach the deepest part of the lung. Combined with other chemical irritants of the MWF, exposure to MWF aerosols containing endotoxin pose a risk to respiratory health problems. PMID:27268595

  15. Focusing by blocking: Repeatedly generating central density peaks in self-propelled particle systems by exploiting diffusive processes

    Science.gov (United States)

    Menzel, Andreas M.

    2015-05-01

    Over the past few years the displacement statistics of self-propelled particles has been intensely studied, revealing their long-time diffusive behavior. Here, we demonstrate that a concerted combination of boundary conditions and switching on and off the self-propelling drive can generate and afterwards arbitrarily often restore a non-stationary centered peak in their spatial distribution. This corresponds to a partial reversibility of their statistical behavior, in opposition to the above-mentioned long-time diffusive nature. Interestingly, it is a diffusive process that mediates and makes possible this procedure. It should be straightforward to verify our predictions in a real experimental system.

  16. Generation of micro-sized PDMS particles by a flow focusing technique for biomicrofluidics applications.

    Science.gov (United States)

    Muñoz-Sánchez, B N; Silva, S F; Pinho, D; Vega, E J; Lima, R

    2016-01-01

    Polydimethylsiloxane (PDMS), due to its remarkable properties, is one of the most widely used polymers in many industrial and medical applications. In this work, a technique based on a flow focusing technique is used to produce PDMS spherical particles with sizes of a few microns. PDMS precursor is injected through a hypodermic needle to form a film/reservoir over the needle's outer surface. This film flows towards the needle tip until a liquid ligament is steadily ejected thanks to the action of a coflowing viscous liquid stream. The outcome is a capillary jet which breaks up into PDMS precursor droplets due to the growth of capillary waves producing a micrometer emulsion. The PDMS liquid droplets in the solution are thermally cured into solid microparticles. The size distribution of the particles is analyzed before and after curing, showing an acceptable degree of monodispersity. The PDMS liquid droplets suffer shrinkage while curing. These microparticles can be used in very varied technological fields, such as biomedicine, biotechnology, pharmacy, and industrial engineering. PMID:27042245

  17. Self-heated hollow cathode discharge system for charged particle sources and plasma generators

    International Nuclear Information System (INIS)

    This paper presents the results of experimental studies of a new design of discharge system using a self-heated hollow cathode. The discharge system offers certain advantages that are attractive for use in high-dose ion implantation, plasma generators, and plasma electron sources.

  18. Numerical simulation of landslide-generated waves using a soil-water coupling smoothed particle hydrodynamics model

    Science.gov (United States)

    Shi, Chuanqi; An, Yi; Wu, Qiang; Liu, Qingquan; Cao, Zhixian

    2016-06-01

    We simulate the generation of a landslide-induced impulse wave with a newly-developed soil-water coupling model in the smoothed particle hydrodynamics (SPH) framework. The model includes an elasto-plastic constitutive model for soil, a Navier-Stokes equation based model for water, and a bilateral coupling model at the interface. The model is tested with simulated waves induced by a slow and a fast landslide. Good agreement is obtained between simulation results and experimental data. The generated wave and the deformation of the landslide body can both be resolved satisfactorily. All parameters in our model have their physical meaning in soil mechanics and can be obtained from conventional soil mechanics experiments directly. The influence of the dilatancy angle of soil shows that the non-associated flow rule must be selected, and the value of the dilatancy angle should not be chosen arbitrarily, if it is not determined with relative experiments.

  19. The generation of high fields for particle acceleration to very high energies

    International Nuclear Information System (INIS)

    A Workshop organised by the CERN Accelerator School, the European Committee for Future Accelerators and the Istituto Nazionale di Fisica Nucleare was held at the Frascati laboratory of INFN during the last week of September 1984. Its purpose was to bring together an inter-disciplinary group of physicists to review ideas for the acceleration of particles to energies beyond those attainable in machines whose construction is underway, or is currently contemplated. These proceedings contain some of the material presented and discussed at the Workshop, comprising papers on topics such as: the free-electron-laser, the lasertron, wakefield accelerators, the laser excitation of droplet arrays, a switched-power linac, plasma beat-wave accelerators and the choice of basic parameters for linear colliders intended for the TeV energy region. (orig.)

  20. High-power, kilojoule class laser channeling, surface wave generation and particle acceleration from underdense plasma

    Science.gov (United States)

    Willingale, L.; Krushelnick, K.; Thomas, A. G. R.; Maksimchuk, A.; Zulick, C.; Nilson, P. M.; Craxton, R. S.; Stoeckl, C.; Sangster, T. C.; Chen, H.; Cobble, J.; Norreys, P. A.; Scott, R. H. H.

    2011-10-01

    Experiments performed on the Omega EP laser facility (750 J of energy in 8.4 ps or 55 J - 300 J of energy in 0.9 ps), provide extreme conditions relevant to fast ignition studies. A CH plasma plume is used as the underdense target and the interaction of the laser pulse channeling through the plasma is imaged using proton radiography. Early time expansion, channel evolution, filamentation and self-correction is measured on a single shot via this method. Structures observed along the channel walls are interpreted as having developed from surface waves, and are a likely injection mechanism of electrons into the cavitated channel for acceleration. High-energy electron and proton spectra are measured and compared for the different pulse lengths from the experiment. Two dimensional particle-in-cell simulations give good agreement to these phenomenon. This work was supported by the National Laser Users' Facility (NLUF) and the DOE (Grant No. DE-NA000874).

  1. Photonic-crystal mediated charged particle beam velocity modulation and electromagnetic wave generation

    International Nuclear Information System (INIS)

    We present the first experimental results of a photonic crystal (PC) structure-mediated charged particle beam velocity modulation and energy exchange. Our structure was based on two photonic lattices working at 9.532 GHz: a modulation lattice (ML) driven by a 2.5-6 W signal to velocity-modulate an electron beam of dc voltage from 15 to 30 kV and current from 50 to 150 μA, and an excitation lattice (EL) to exchange energy with the modulated beam, similar to a two-cavity klystron. Experimental results successfully demonstrated high spectral purity from signals excited by the velocity-modulated beam in the EL, with power level in excellent agreement with conventional theories. (paper)

  2. Comparing activated carbon of different particle sizes on enhancing methane generation in upflow anaerobic digester.

    Science.gov (United States)

    Xu, Suyun; He, Chuanqiu; Luo, Liwen; Lü, Fan; He, Pinjing; Cui, Lifeng

    2015-11-01

    Two sizes of conductive particles, i.e. 10-20 mesh granulated activated carbon (GAC) and 80-100 mesh powdered activated carbon (PAC) were added into lab-scale upflow anaerobic sludge blanket reactors, respectively, to testify their enhancement on the syntrophic metabolism of alcohols and volatile fatty acids (VFAs) in 95days operation. When OLR increased to more than 5.8gCOD/L/d, the differences between GAC/PAC supplemented reactors and the control reactor became more significant. The introduction of activated carbon could facilitate the enrichment of methanogens and accelerate the startup of methanogenesis, as indicated by enhanced methane yield and substrate degradation. High-throughput pyrosequencing analysis showed that syntrophic bacteria and Methanosarcina sp. with versatile metabolic capability increased in the tightly absorbed fraction on the PAC surface, leading to the promoted syntrophic associations. Thus PAC prevails over than GAC for methanogenic reactor with heavy load. PMID:26298405

  3. Study of a positron source generated by photons from ultrarelativistic channeled particles

    International Nuclear Information System (INIS)

    Radiation by channeled electrons in Germanium and Silicon crystals along the axis is studied as a very promising photon source of small angular divergence for positron generation in amorphous targets. Radiation rates for different crystal lengths - from some tenths of mm to 10 mm - and two electron incident energies, 5 and 20 GeV, are considered and a comparison between the two crystals is presented. Thermic behaviour of the crystal under incidence of bunches of 1010 electrons is also examined. The corresponding positron yields for tungsten amorphous converters - of 0.5 and 1 Xo thickness - are calculated considering the case of a Germanium photon generator. Assuming a large acceptance optical matching system as the adiabatic device of the SLC, accepted positrons are evaluated and positron yields larger than 1 e+/e- are obtained

  4. Analysis of airborne particulate matter

    International Nuclear Information System (INIS)

    An airborne particulate matter (APM) consists of many kinds of solid and liquid particles in air. APM analysis methods and the application examples are explained on the basis of paper published after 1998. Books and general remarks, sampling and the measurement of concentration and particle distribution, elemental analysis methods and the present state of analysis of species are introduced. Tapered Element Oscillating Microbalance (TEOM) method can collect continuously the integrating mass, but indicates lower concentration. Cu, Ni, Zn, Co, Fe(2), Mn, Cd, Fe(3) and Pb, the water-soluble elements, are determined by ion-chromatography after ultrasonic extraction of the aqueous solution. The detection limit of them is from 10 to 15 ppb (30 ppb Cd and 60 ppb Pb). The elemental carbon (EC) and organic carbon (OC) are separated by the thermal mass measurement-differential scanning calorimeter by means of keeping at 430degC for 60 min. 11 research organizations compared the results of TC (Total Carbon) and EC by NIOSH method 5040 and the thermal method and obtained agreement of TC. ICP-MS has been developed in order to determine correctly and quickly the trace elements. The determination methods for distinction of chemical forms in the environment were developed. GC/MS, LC/MS and related technologies for determination of organic substances are advanced. Online real-time analysis of APN, an ideal method, is examined. (S.Y.)

  5. Validation of proton ionization cross section generators for Monte Carlo particle transport

    CERN Document Server

    Batic, Matej; Saracco, Paolo

    2011-01-01

    Three software systems, ERCS08, ISICS 2011 and \\v{S}mit's code, that implement theoretical calculations of inner shell ionization cross sections by proton impact, are validated with respect to experimental data. The accuracy of the cross sections they generate is quantitatively estimated and inter-compared through statistical methods. Updates and extensions of a cross section data library relevant to PIXE simulation with Geant4 are discussed.

  6. Solar gas turbine systems with centrifugal particle receivers, for remote power generation

    OpenAIRE

    Prosin, Tobias; Pryor, Trevor; Creagh, Christine; Amsbeck, Lars; Uhlig, Ralf

    2015-01-01

    There is a growing demand from remote communities in Australia to increase the amount of decentralised renewable energy in their energy supply mix in order to decrease their fuel costs. In contrast to large scale concentrated solar power (CSP) plants, small solar-hybrid gas turbine systems promise a way to decentralise electricity generation at power levels in the range of 0.1- 10 MWe, and reduce to cost of energy production for off-grid, isolated communities. Thermal storage provides such...

  7. Self-consistent simulation of torque generation by radial current due to fast particles

    International Nuclear Information System (INIS)

    Toroidal rotation plays an important role in transport and stability of burning plasmas, and clarification of the mechanism of rotations spontaneously generated by perpendicular NBI and ICRF can help evaluate the rotations in the plasmas quantitatively, contributing to accurate control of them. In order to study the properties of plasma rotations, one-dimensional multi-fluid transport code TASK/TX has been developed, which is the first code to self-consistently solve a tokamak plasma evolution including a plasma rotation and a radial electric field Er. TASK/TX automatically generates a return current jbulk due to the charge separation originated from the difference in electron and ion banana orbit widths, resulting in a j-vectorbulk x B-vector torque on a bulk plasma. Through the simulations, we confirm the generated torque drives a toroidal rotation accompanied by the modification of a radial electric field without having to add extra torque input term in equations of motion, while a poloidal rotation almost remains unchanged. It is found that the toroidal rotation decreases with a weaker dependence than inversely proportional as the turbulent viscosity increases. (author)

  8. Heavy Bino Dark Matter and Collider Signals in the MSSM with Vector-like 4th-Generation Particles

    CERN Document Server

    Abdullah, Mohammad; Iwamoto, Sho; Lillard, Benjamin

    2016-01-01

    MSSM4G models, in which the minimal supersymmetric standard model is extended to include vector-like copies of standard model particles, are promising possibilities for weak-scale supersymmetry. In particular, two models, called QUE and QDEE, realize the major virtues of supersymmetry (naturalness consistent with the 125 GeV Higgs boson, gauge coupling unification, and thermal relic neutralino dark matter) without the need for fine-tuned relations between particle masses. We determine the implications of these models for dark matter and collider searches. The QUE and QDEE models revive the possibility of heavy Bino dark matter with mass in the range 300-700 GeV, which is not usually considered. Dark matter direct detection cross sections are typically below current limits, but are naturally expected above the neutrino floor and may be seen at next-generation experiments. Indirect detection prospects are bright at the Cherenkov Telescope Array, provided the 4th-generation leptons have mass above 350 GeV or dec...

  9. 3Dtrapping and manipulation of micro-particles using holographic optical tweezers with optimized computer-generated holograms

    Institute of Scientific and Technical Information of China (English)

    Tao Tao; Jing Li; Qian Long; Xiaoping Wu

    2011-01-01

    A multi-plane adaptive-additive algorithm is developed for optimizing computer-generated holograms for the reconstruction of traps in three-dimensional (3D) spaces. This algorithm overcomes the converging stagnation problem of the traditional multi-plane Gerchberg-Saxton algorithm and improves the diffraction efficiency of the holograms effectively. The optimized holograms are applied in a holographic optical tweezers (HOT) platform. Additionally, a computer program is developed and integrated into the HOT platform for the purpose of achieving the interactive control of traps. Experiments demonstrate that the manipulation of micro-particles into the 3D structure with optimized holograms can be carried out effectively on the HOT platform.%A multi-plane adaptive-additive algorithm is developed for optimizing computer-generated holograms for the reconstruction of traps in three-dimensional (3D) spaces.This algorithm overcomes the converging stagnation problem of the traditional multi-plane Gerchberg-Saxton algorithm and improves the diffraction efficiency of the holograms effectively.The optimized holograms are applied in a holographic optical tweezers (HOT) platform.Additionally,a computer program is developed and integrated into the HOT platform for the purpose of achieving the interactive control of traps.Experiments demonstrate that the manipulation of micro-particles into the 3D structure with optimized holograms can be carried out effectively on the HOT platform.

  10. Evaluation of H2O2-generation during oxygen reduction at electrodeposited Pt particles on mask scratched electrodes

    International Nuclear Information System (INIS)

    In this study, the Pt particle deposition was systematically performed by our proposed mask scratch and subsequent Pt electrodeposition in order to investigate the H2O2-byproduct generation efficiency during O2 reduction. By peeling a part of polymer layer coated on a glassy carbon substrate using an atomic force microscope cantilever, scratched areas are regularly made. The Pt particles are deposited only on the above-mentioned scratched areas, indicating that the controlled Pt deposition has been achieved. The background cyclic voltammetry of the prepared electrodes showed that the deposited nanoparticles are certainly composed of Pt. Moreover, the electrochemical surface area of the deposited Pt (Pt-ESA) linearly increases with the increasing scratched area, revealing that the Pt-ESAs can be controlled by the mask scratch-based Pt electrodeposition method. It should be noted that an increase in the Pt-ESA not only increases the O2 reduction currents, but also enhances the H2O2 generation efficiency.

  11. Sedimentation behavior of indoor airborne microparticles

    Institute of Scientific and Technical Information of China (English)

    LI Ming; WU Chao; PAN Wei

    2008-01-01

    Experiments on the behavior of airborne microparticle sediments and their adhesion on glass slides were conducted in a laboratory located on the first floor of a teaching building. Clean tiles and glass slides were placed at different angles (0°, 45° and 90°) with respect to the horizontal plane in the laboratory. The sedimentation of microparticles was investigated at certain time intervals (1 d, 3 d, 10 d and 30 d). The results of testing, at day 30, show that the diameters of particles on the horizontal tiles varied from 20 to 80 μm; few particles with diameter less than 0.5 μm or greater than 100 μm were found. The amount of particle sediment on all the slides increased along over time, while the average diameter of particles was not correlated with time, nor with the angle of placement. The maximum particle size, the total particle surface area, the total perimeter of all particles and the cover ratio of light (the proportion of total area of particles to the observed area of the slides surfaces) did not change significantly within the first 10 days. Inspection of all the samples for the last 20 days, however, showed that these variables increased substantially with the passage of time and were in reverse proportion to the placement angles, which indicates a concentration of particles, as well as physical and chemical changes.

  12. Generation and preclinical immunogenicity study of dengue type 2 virus-like particles derived from stably transfected mosquito cells.

    Science.gov (United States)

    Suphatrakul, Amporn; Yasanga, Thippawan; Keelapang, Poonsook; Sriburi, Rungtawan; Roytrakul, Thaneeya; Pulmanausahakul, Rojjanaporn; Utaipat, Utaiwan; Kawilapan, Yanee; Puttikhunt, Chunya; Kasinrerk, Watchara; Yoksan, Sutee; Auewarakul, Prasert; Malasit, Prida; Charoensri, Nicha; Sittisombut, Nopporn

    2015-10-13

    Recent phase IIb/III trials of a tetravalent live attenuated vaccine candidate revealed a need for improvement in the stimulation of protective immunity against diseases caused by dengue type 2 virus (DENV-2). Our attempts to develop particulate antigens for possibly supplementing live attenuated virus preparation involve generation and purification of recombinant DENV-2 virus-like particles (VLPs) derived from stably (prM+E)-expressing mosquito cells. Two VLP preparations generated with either negligible or enhanced prM cleavage exhibited different proportions of spherical particles and tubular particles of variable lengths. In BALB/c mice, VLPs were moderately immunogenic, requiring adjuvants for the induction of strong virus neutralizing antibody responses. VLPs with enhanced prM cleavage induced higher levels of neutralizing antibody than those without, but the stimulatory activity of both VLPs was similar in the presence of adjuvants. Comparison of EDIII-binding antibodies in mice following two adjuvanted doses of these VLPs revealed subtle differences in the stimulation of anti-EDIII binding antibodies. In cynomolgus macaques, VLPs with enhanced prM cleavage augmented strongly neutralizing antibody and EDIII-binding antibody responses in live attenuated virus-primed recipients, suggesting that these DENV-2 VLPs may be useful as the boosting antigen in prime-boost immunization. As the levels of neutralizing antibody induced in macaques with the prime-boost immunization were comparable to those infected with wild type virus, this virus-prime VLP-boost regimen may provide an immunization platform in which a need for robust neutralizing antibody response in the protection against DENV-2-associated illnesses could be tested. PMID:26382602

  13. APSTNG: Associated particle sealed-tube neutron generator studies for arms control. Final report on NN-20 Project ST220

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, E.; Dickerman, C.E.; Brunner, T.; Hess, A.; Tylinski, S.

    1994-12-01

    Argonne National Laboratory has performed research and development on the use of Associated Particle Sealed-Tube Neutron Generator (APSTNG) technology for treaty verification and non-proliferation applications, under funding from the DOE Office of Nonproliferation and National Security. Results indicate that this technology has significant potential for nondestructively detecting elemental compositions inside inspected objects or volumes. The final phase of this project was placement of an order for commercial procurement of an advanced sealed tube, with its high-voltage supply and control systems. Procurement specifications reflected lessons learned during the study. The APSTNG interrogates a volume with a continuous 14-MeV neutron flux. Each neutron is emitted coincident with an {open_quotes}associated{close_quotes} alpha-particle emitted in the opposite direction. Thus detection of an alpha-particle marks the emission of a neutron in a cone opposite to that defined by the alpha detector. Detection of a gamma ray coincident with the alpha indicates that the gamma was emitted from a neutron-induced reaction inside the neutron cone: the gamma spectra can be used to identify fissionable materials and many isotopes having an atomic number larger than that of boron. The differences in gamma-ray and alpha-particle detection times yield a coarse measurement of the distance along the cone axis from the APSTNG emitter to each region containing the identified nuclide. A position-sensitive alpha detector would permit construction of coarse three-dimensional images. The source and emission-detection systems can be located on the same side of the interrogated volume. The neutrons and gamma rays are highly penetrating. A relatively high signal-to-background ratio allows the use of a relatively small neutron source and conventional electronics.

  14. An Analysis of Measurement Calibration Specifications for Light-scattering Airborne Particle Counter%能量色散X射线荧光法快速检测玩具中铅方法的问题分析及应对措施

    Institute of Scientific and Technical Information of China (English)

    李学云; 陈子凡; 勾正伦; 彭首创

    2013-01-01

    结合美国和欧盟在X射线荧光光谱法检测玩具中铅的报告和标准方法,对X射线荧光光谱仪进行了分类剖析,列举能量色散X射线荧光光谱仪检测玩具中铅的优势,分析现阶段还存在的问题,结合理论和实践对问题逐一提出应对措施,为建立X射线荧光光谱法检测玩具中铅的标准方法提供正确方向和理论基础.%As the main equipment to monitor the clean space,the light-scattering airborne particle counter has been widely used and caught more attention on its capability.In recent years,many kinds of measurements of the airborne particle counter have been made,which brings troubles to the manufacturing corporations and measurement organizations.This paper introduces the domestic and international counter measurement standards,and focuses on the comparison and analysis of domestic standards JJF 1190 and GJB/J 5416.

  15. Measured and modelled concentrations and vertical profiles of airborne particulate matter within the boundary layer of a street canyon

    International Nuclear Information System (INIS)

    Concentrations and vertical profiles of various fractions of airborne particulate matter (suspended particulate matter (SPM), PM10 and PM2.5) have been measured over the first three metres from ground in a street canyon. Measurements were carried out using automated near real-time apparatus called the Kinetic Sequential Sampling (KSS) system. KSS system is essentially an electronically-controlled lift carrying a real-time particle monitor for sampling air sequentially, at different heights within the breathing zone, which includes all heights within the surface layer of a street canyon at which people may breathe. Data is automatically logged at the different receptor levels, for the determination of the average vertical concentration profile of airborne particulate matter. For measuring the airborne particle concentration, a Grimm Dust Monitor 1.104/5 was used. The recorded data also allows for time series analysis of airborne particulate matter concentration at different heights. Time series data and hourly-average vertical concentration profiles in the boundary layer of the confines of a street are thought to be mainly determined by traffic emissions and traffic associated processes. Hence the measured data were compared with results of a street canyon emission-dispersion model in time and space. This Street Level Air Quality (SLAQ) model employs the plume-box technique and includes modules for simulating vehicle-generated effects such as thermally- and mechanically-generated turbulence and resuspension of road dust. Environmental processes, such as turbulence resulting from surface sensible heat and the formation of sulphate aerosol from sulphur dioxide exhaust emissions, are taken into account. The paper presents an outline description of the measuring technique and model used, and a comparison of the measured and modelled data

  16. Airborne forest fire research

    Science.gov (United States)

    Mattingly, G. S.

    1974-01-01

    The research relating to airborne fire fighting systems is reviewed to provide NASA/Langley Research Center with current information on the use of aircraft in forest fire operations, and to identify research requirements for future operations. A literature survey, interview of forest fire service personnel, analysis and synthesis of data from research reports and independent conclusions, and recommendations for future NASA-LRC programs are included.

  17. Particulate airborne impurities

    OpenAIRE

    Wilkinson, Kai

    2013-01-01

    The cumulative effects of air pollutants are of principal concern in research on environmental protection in Sweden. Post-industrial society has imposed many limits on emitted air pollutants, yet the number of reports on the negative effects from them is increasing, largely due to human activity in the form of industrial emissions and increased traffic flows. Rising concerns over the health effects from airborne particulate matter (PM) stem from in vitro, in vivo, and cohort studies revealing...

  18. GRYPHON : Airborne lifestyle concept

    OpenAIRE

    Evers, Erik

    2014-01-01

    The result of the project, the Gryphon, is a helicopter concept designed for private use. The intention of the project has been to investigate how safe, personal airborne mobility could be an attractive transportation alternative in the future. As an aspirational concept the goal has been to inspire and show an exciting way to enjoy a modern, sustainable lifestyle close to nature without the need for conventional infrastructure.

  19. Legal requirements and guidelines for the control of harmful laser generated particles, vapours and gases

    Science.gov (United States)

    Horsey, John

    2015-07-01

    This paper is a review of the Health and Safety laws and guidelines relating to laser generated emissions into the workplace and outside environment with emphasis on the differences between legal requirements and guideline advice. The types and nature of contaminants released by various laser processes (i.e. cutting, coding, engraving, marking etc) are discussed, together with the best methods for controlling them to within legal exposure limits. A brief description of the main extract air filtration techniques, including the principles of particulate removal and the action of activated carbon for gas/vapour/odour filtration, is given.

  20. Generation of Nano-Catalyst Particles by Spinodal Nano-Decomposition in Perovskite

    OpenAIRE

    Kizaki, Hidetoshi; Kusakabe, Koichi; Nogami, Soichiro; Katayama-Yoshida, Hiroshi

    2008-01-01

    A new mechanism of nano-catalyst generation based on the spinodal nano-decomposition in self-regenerating perovskite catalysts for automotive-emissions control is proposed. To demonstrate existence of the spinodal nano-decomposition in real perovskite catalysts, we performed first-principles calculations to evaluate the free energy of La(Fe$_{1-x}$Pd$_x$)O$_3$ and La(Fe$_{1-x}$Rh$_x$)O$_3$. The result indicates appearance of a spinodal region in the phase diagram of each material. Formation o...

  1. Airborne wireless communication systems, airborne communication methods, and communication methods

    Science.gov (United States)

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  2. Laser light scattering from silicon particles generated in an argon diluted silane plasma

    Science.gov (United States)

    Qin, Y.; Kortshagen, U. R.; Aydil, E. S.

    2016-03-01

    We conducted laser light scattering (LLS) measurements in a 13.56 MHz capacitively coupled dusty plasma maintained in silane and argon to study the spatial distribution of silicon nanoparticles and nanoparticle agglomerates. Specifically, we focused on the temporal evolution of their spatial distribution in the plasma as a function of pressure and power. We observed three distinct types of temporal evolution behavior of the nanoparticle dust cloud in the plasma and classified these into three regimes based on pressure and power. Each regime features a distinct pattern in laser light scattering measurements. At low pressures (˜80-100 mTorr) and high powers (˜40-60 W) we observed periodically repeating expansions and contractions of a continuous dust cloud for the first time. Dust voids, which have been reported before, were also observed at high pressures (˜100-150 mTorr) and low powers (˜20-40 W) in the center of the plasma. A mechanism is proposed to explain the observed dynamics of the nanoparticles. The balance between the ion drag force and electrostatic forces and their dependence on particle size are hypothesized to be the dominant factors that determine the nanoparticle cloud dynamics.

  3. Study of defect generated visible photoluminescence in zinc oxide nano-particles prepared using PVA templates

    Energy Technology Data Exchange (ETDEWEB)

    Oudhia, A. [Department of Physics, Government V.Y.T. PG. Autonomous College, Durg, 491001 C.G. (India); Choudhary, A., E-mail: aarti.bhilai@gmail.com [Department of Physics, Government V.Y.T. PG. Autonomous College, Durg, 491001 C.G. (India); Sharma, S.; Aggrawal, S. [Department of Physics, Government V.Y.T. PG. Autonomous College, Durg, 491001 C.G. (India); Dhoble, S.J. [RTM University Nagpur, Maharashtra (India)

    2014-10-15

    Intrinsic defect generated photoluminescence (PL) in zinc oxide nanoparticles (NPs) obtained by a PVA template based wet-chemical process has been studied. A good controllability was achieved on the surface defects, structure and the morphology of ZnO NPs through the variation of solvents used in synthesis. The PL emission strongly depended on the defect structure and morphology. SEM, XRD, annealing and PL excitation studies were used to analyze the types of defects involved in the visible emission as well as the defect concentration. The mechanism for the blue, green and yellow emissions was proposed. The spectral content of the visible emission was controlled through generation/removal of defects through the shape transformation or annealing by focusing on defect origins and broad controls. - Highlights: • ZnO nanoparticles were synthesized using poly-vinyl alcohol template in various solvents. • The structure and morphology of ZnO nanoparticles were depended on dielectric constant and boiling point of solvents. • Photoluminescence properties of ZnO nanoparticles were studied. • Maximum optical absorbance and Photoluminescence intensity were found in ethanolic preparation. • ZnO nanoparticles were annealed at different temperatures for detection of defect emission.

  4. A new generation Nb3Sn wire, and the prospects for its use in particle accelerators

    International Nuclear Information System (INIS)

    The US DOE has initiated a Conductor Development Program aimed at demonstrating a high current density, cost effective Nb3Sn conductor for use in accelerator magnets. The first goal, an increase in current density by 50%, has been achieved in a practical conductor. The program is focused at present on achieving the second goal of reduced losses. The different approaches for achieving these goals will be discussed, and the status will be presented. Magnet technology R and D has been proceeding in parallel with the conductor development efforts, and these two technologies are reaching the level required for the next step--introduction into operating accelerator magnets. An obvious point for introducing this technology is the LHC interaction region magnets, which require large apertures and high fields (or high field gradients). By upgrading the interaction region magnets, machine performance can be enhanced significantly without replacing the arc magnets, which represent most of the cost of an accelerator. Design requirements generated by recent studies and workshops will be reviewed, and a roadmap for the development of the next-generation interaction region magnets will be presented

  5. Study of defect generated visible photoluminescence in zinc oxide nano-particles prepared using PVA templates

    International Nuclear Information System (INIS)

    Intrinsic defect generated photoluminescence (PL) in zinc oxide nanoparticles (NPs) obtained by a PVA template based wet-chemical process has been studied. A good controllability was achieved on the surface defects, structure and the morphology of ZnO NPs through the variation of solvents used in synthesis. The PL emission strongly depended on the defect structure and morphology. SEM, XRD, annealing and PL excitation studies were used to analyze the types of defects involved in the visible emission as well as the defect concentration. The mechanism for the blue, green and yellow emissions was proposed. The spectral content of the visible emission was controlled through generation/removal of defects through the shape transformation or annealing by focusing on defect origins and broad controls. - Highlights: • ZnO nanoparticles were synthesized using poly-vinyl alcohol template in various solvents. • The structure and morphology of ZnO nanoparticles were depended on dielectric constant and boiling point of solvents. • Photoluminescence properties of ZnO nanoparticles were studied. • Maximum optical absorbance and Photoluminescence intensity were found in ethanolic preparation. • ZnO nanoparticles were annealed at different temperatures for detection of defect emission

  6. Solar tower power plant using a particle-heated steam generator: Modeling and parametric study

    Science.gov (United States)

    Krüger, Michael; Bartsch, Philipp; Pointner, Harald; Zunft, Stefan

    2016-05-01

    Within the framework of the project HiTExStor II, a system model for the entire power plant consisting of volumetric air receiver, air-sand heat exchanger, sand storage system, steam generator and water-steam cycle was implemented in software "Ebsilon Professional". As a steam generator, the two technologies fluidized bed cooler and moving bed heat exchangers were considered. Physical models for the non-conventional power plant components as air- sand heat exchanger, fluidized bed coolers and moving bed heat exchanger had to be created and implemented in the simulation environment. Using the simulation model for the power plant, the individual components and subassemblies have been designed and the operating parameters were optimized in extensive parametric studies in terms of the essential degrees of freedom. The annual net electricity output for different systems was determined in annual performance calculations at a selected location (Huelva, Spain) using the optimized values for the studied parameters. The solution with moderate regenerative feed water heating has been found the most advantageous. Furthermore, the system with moving bed heat exchanger prevails over the system with fluidized bed cooler due to a 6 % higher net electricity yield.

  7. Influence of physical properties and chemical composition of sample on formation of aerosol particles generated by nanosecond laser ablation at 213 nm

    Energy Technology Data Exchange (ETDEWEB)

    Hola, Marketa, E-mail: mhola@sci.muni.c [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Konecna, Veronika [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Mikuska, Pavel [Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic v.v.i., Veveri 97, 602 00 Brno (Czech Republic); Kaiser, Jozef [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); Kanicky, Viktor [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)

    2010-01-15

    The influence of sample properties and composition on the size and concentration of aerosol particles generated by nanosecond Nd:YAG laser ablation at 213 nm was investigated for three sets of different materials, each containing five specimens with a similar matrix (Co-cemented carbides with a variable content of W and Co, steel samples with minor differences in elemental content and silica glasses with various colors). The concentration of ablated particles (particle number concentration, PNC) was measured in two size ranges (10-250 nm and 0.25-17 mum) using an optical aerosol spectrometer. The shapes and volumes of the ablation craters were obtained by Scanning Electron Microscopy (SEM) and by an optical profilometer, respectively. Additionally, the structure of the laser-generated particles was studied after their collection on a filter using SEM. The results of particle concentration measurements showed a significant dominance of particles smaller than 250 nm in comparison with larger particles, irrespective of the kind of material. Even if the number of particles larger than 0.25 mum is negligible (up to 0.1%), the volume of large particles that left the ablation cell can reach 50% of the whole particle volume depending on the material. Study of the ablation craters and the laser-generated particles showed a various number of particles produced by different ablation mechanisms (particle splashing or condensation), but the similar character of released particles for all materials was observed by SEM after particle collection on the membrane filter. The created aerosol always consisted of two main structures - spherical particles with diameters from tenths to units of micrometers originally ejected from the molten surface layer and mum-sized 'fibres' composed of primary agglomerates with diameters in the range between tens and hundreds of nanometers. The shape and structure of ablation craters were in good agreement with particle concentration

  8. RADCHARM++: A C++ routine to compute the electromagnetic radiation generated by relativistic charged particles in crystals and complex structures

    International Nuclear Information System (INIS)

    The analytical theories of coherent bremsstrahlung and channeling radiation well describe the process of radiation generation in crystals under some special cases. However, the treatment of complex situations requires the usage of a more general approach. In this report we present a C++ routine, named RADCHARM++, to compute the electromagnetic radiation emitted by electrons and positrons in crystals and complex structures. In the RADCHARM++ routine, the model for the computation of e.m. radiation generation is based on the direct integration of the quasiclassical formula of Baier and Katkov. This approach allows one taking into account real trajectories, and thereby the contribution of incoherent scattering. Such contribution can be very important in many cases, for instance for electron channeling. The generality of the Baier–Katkov operator method permits one to simulate the electromagnetic radiation emitted by electrons/positrons in very different cases, e.g., in straight, bent and periodically bent crystals, and for different beam energy ranges, from sub-GeV to TeV and above. The RADCHARM++ routine has been implemented in the Monte Carlo code DYNECHARM++, which solves the classical equation of motion of charged particles traveling through a crystal under the continuum potential approximation. The code has proved to reproduce the results of experiments performed at the MAinzer MIkrotron (MAMI) with 855 MeV electrons and has been used to predict the radiation spectrum generated by the same electron beam in a bent crystal

  9. RADCHARM++: A C++ routine to compute the electromagnetic radiation generated by relativistic charged particles in crystals and complex structures

    Energy Technology Data Exchange (ETDEWEB)

    Bandiera, Laura; Bagli, Enrico; Guidi, Vincenzo [INFN Sezione di Ferrara and Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, 44121 Ferrara (Italy); Tikhomirov, Victor V. [Research Institute for Nuclear Problems, Belarusian State University, Minsk (Belarus)

    2015-07-15

    The analytical theories of coherent bremsstrahlung and channeling radiation well describe the process of radiation generation in crystals under some special cases. However, the treatment of complex situations requires the usage of a more general approach. In this report we present a C++ routine, named RADCHARM++, to compute the electromagnetic radiation emitted by electrons and positrons in crystals and complex structures. In the RADCHARM++ routine, the model for the computation of e.m. radiation generation is based on the direct integration of the quasiclassical formula of Baier and Katkov. This approach allows one taking into account real trajectories, and thereby the contribution of incoherent scattering. Such contribution can be very important in many cases, for instance for electron channeling. The generality of the Baier–Katkov operator method permits one to simulate the electromagnetic radiation emitted by electrons/positrons in very different cases, e.g., in straight, bent and periodically bent crystals, and for different beam energy ranges, from sub-GeV to TeV and above. The RADCHARM++ routine has been implemented in the Monte Carlo code DYNECHARM++, which solves the classical equation of motion of charged particles traveling through a crystal under the continuum potential approximation. The code has proved to reproduce the results of experiments performed at the MAinzer MIkrotron (MAMI) with 855 MeV electrons and has been used to predict the radiation spectrum generated by the same electron beam in a bent crystal.

  10. Generation of recombinant porcine parvovirus virus-like particles in Saccharomyces cerevisiae and development of virus-specific monoclonal antibodies.

    Science.gov (United States)

    Tamošiūnas, Paulius Lukas; Petraitytė-Burneikienė, Rasa; Lasickienė, Rita; Akatov, Artiomas; Kundrotas, Gabrielis; Sereika, Vilimas; Lelešius, Raimundas; Žvirblienė, Aurelija; Sasnauskas, Kęstutis

    2014-01-01

    Porcine parvovirus (PPV) is a widespread infectious virus that causes serious reproductive diseases of swine and death of piglets. The gene coding for the major capsid protein VP2 of PPV was amplified using viral nucleic acid extract from swine serum and inserted into yeast Saccharomyces cerevisiae expression plasmid. Recombinant PPV VP2 protein was efficiently expressed in yeast and purified using density gradient centrifugation. Electron microscopy analysis of purified PPV VP2 protein revealed the self-assembly of virus-like particles (VLPs). Nine monoclonal antibodies (MAbs) against the recombinant PPV VP2 protein were generated. The specificity of the newly generated MAbs was proven by immunofluorescence analysis of PPV-infected cells. Indirect IgG ELISA based on the recombinant VLPs for detection of PPV-specific antibodies in swine sera was developed and evaluated. The sensitivity and specificity of the new assay were found to be 93.4% and 97.4%, respectively. In conclusion, yeast S. cerevisiae represents a promising expression system for generating recombinant PPV VP2 protein VLPs of diagnostic relevance. PMID:25045718

  11. Generation of Recombinant Porcine Parvovirus Virus-Like Particles in Saccharomyces cerevisiae and Development of Virus-Specific Monoclonal Antibodies

    Directory of Open Access Journals (Sweden)

    Paulius Lukas Tamošiūnas

    2014-01-01

    Full Text Available Porcine parvovirus (PPV is a widespread infectious virus that causes serious reproductive diseases of swine and death of piglets. The gene coding for the major capsid protein VP2 of PPV was amplified using viral nucleic acid extract from swine serum and inserted into yeast Saccharomyces cerevisiae expression plasmid. Recombinant PPV VP2 protein was efficiently expressed in yeast and purified using density gradient centrifugation. Electron microscopy analysis of purified PPV VP2 protein revealed the self-assembly of virus-like particles (VLPs. Nine monoclonal antibodies (MAbs against the recombinant PPV VP2 protein were generated. The specificity of the newly generated MAbs was proven by immunofluorescence analysis of PPV-infected cells. Indirect IgG ELISA based on the recombinant VLPs for detection of PPV-specific antibodies in swine sera was developed and evaluated. The sensitivity and specificity of the new assay were found to be 93.4% and 97.4%, respectively. In conclusion, yeast S. cerevisiae represents a promising expression system for generating recombinant PPV VP2 protein VLPs of diagnostic relevance.

  12. New generation of monolithic active pixel sensors for charged particle detection; Developpement d'un capteur de nouvelle generation et son electronique integree pour les collisionneurs futurs

    Energy Technology Data Exchange (ETDEWEB)

    Deptuch, G

    2002-09-01

    Vertex detectors are of great importance in particle physics experiments, as the knowledge of the event flavour is becoming an issue for the physics programme at Future Linear Colliders. Monolithic Active Pixel Sensors (MAPS) based on a novel detector structure have been proposed. Their fabrication is compatible with a standard CMOS process. The sensor is inseparable from the readout electronics, since both of them are integrated on the same, low-resistivity silicon wafer. The basic pixel configuration comprises only three MOS transistors and a diode collecting the charge through thermal diffusion. The charge is generated in the thin non-depleted epitaxial layer underneath the readout electronics. This approach provides, at low cost, a high resolution and thin device with the whole area sensitive to radiation. Device simulations using the ISE-TCAD package have been carried out to study the charge collection mechanism. In order to demonstrate the viability of the technique, four prototype chips have been fabricated using different submicrometer CMOS processes. The pixel gain has been calibrated using a {sup 55}Fe source and the Poisson sequence method. The prototypes have been exposed to high-energy particle beams at CERN. The tests proved excellent detection performances expressed in a single-track spatial resolution of 1.5 {mu}m and detection efficiency close to 100%, resulting from a SNR ratio of more than 30. Irradiation tests showed immunity of MAPS to a level of a few times 10{sup 12} n/cm{sup 2} and a few hundred kRad of ionising radiation. The ideas for future work, including on-pixel signal amplification, double sampling operation and current mode pixel design are present as well. (author)

  13. Wave generation and particle transport in the plasma sheet and boundary layer. Semiannual report

    International Nuclear Information System (INIS)

    The one and two ion beam instability was considered as a possible explanation for the observations of broadband electrostatic noise in the plasma sheet region of the geomagnetic tail. When only hot streaming plasma sheet boundary layer ions were present, no broadband waves were excited. Cold, streaming ionospheric ions can generate electrostatic broadband waves propagating in the slow beam-acoustic mode, but the growth rates of the waves were significantly enhanced when warm boundary layer ions were presented. (Both the slow and fast beam-acoustic modes can be excited, depending on the relative ion drift.) This mode predicted that the wave intensity of the broadband noise should peak in the plasma sheet boundary layer (PSBL). Observations of less intense electrostatic waves in the lobes and plasma sheet were likely a result of the absence of warm ion beams or large ion temperatures, respectively, which resulted in smaller growth rates. The model dependence of the ion beam instability has also been studied. For cold and warm ions streaming in the same direction, researchers found wave growth peaked for wave normal angles theta = 0 deg. and wave frequencies approx. 0.1 x the electron plasma frequency. However, for anti-parallel streaming cold and warm ions, wave growth peaks near theta = 90 deg. and wave frequencies were an order of magnitude smaller

  14. Wave generation and particle transport in the plasma sheet and boundary layer

    Science.gov (United States)

    Dusenbery, P. B.

    1987-01-01

    The one and two ion beam instability was considered as a possible explanation for the observations of broadband electrostatic noise in the plasma sheet region of the geomagnetic tail. When only hot streaming plasma sheet boundary layer ions were present, no broadband waves were excited. Cold, streaming ionospheric ions can generate electrostatic broadband waves propagating in the slow beam-acoustic mode, but the growth rates of the waves were significantly enhanced when warm boundary layer ions were presented. (Both the slow and fast beam-acoustic modes can be excited, depending on the relative ion drift.) This mode predicted that the wave intensity of the broadband noise should peak in the plasma sheet boundary layer (PSBL). Observations of less intense electrostatic waves in the lobes and plasma sheet were likely a result of the absence of warm ion beams or large ion temperatures, respectively, which resulted in smaller growth rates. The model dependence of the ion beam instability has also been studied. For cold and warm ions streaming in the same direction, researchers found wave growth peaked for wave normal angles theta = 0 deg. and wave frequencies approx. 0.1 x the electron plasma frequency. However, for anti-parallel streaming cold and warm ions, wave growth peaks near theta = 90 deg. and wave frequencies were an order of magnitude smaller.

  15. Ultrafast terawatt laser sources for high-field particle acceleration and short wavelength generation

    International Nuclear Information System (INIS)

    The Laser Sources working group concerned itself with recent advances in and future requirements for the development of laser sources relevant to high-energy physics (HEP) colliders, small scale accelerators, and the generation of short wave-length radiation. We heavily emphasized pulsed terawatt peak power laser sources for several reasons. First, their development over the past five years has been rapid and multi-faceted, and has made relativistic light intensity available to the advanced accelerator community, as well as the wider physics community, for the first time. Secondly, they have strongly impacted plasma-based accelerator research over the past two years, producing the first experimental demonstrations of the laser wakefield accelerator (LWFA) in both its resonantly-driven and self-modulated forms. Thirdly, their average power and wall-plug efficiency currently fall well short of projected requirements for future accelerators and other high average power applications, but show considerable promise for improving substantially over the next few years. A review of this rapidly emerging laser technology in the context of advanced accelerator research is therefore timely

  16. ASHRAE IAQ 2010: Airborne infection controlventilation, IAQ & energy

    DEFF Research Database (Denmark)

    Sekhar, Chandra; Olesen, Bjarne W.

    2012-01-01

    . • Knowledge that proximity to an infected person affects infection rate, but the continued lack of certainty about whether that is due to large "ballistic" droplets or just a higher concentration of smaller airborne particles. Besides the papers from the IAQ 2010 conference mentioned above, this special issue...

  17. Skin Damage Mechanisms Related to Airborne Particulate Matter Exposure.

    Science.gov (United States)

    Magnani, Natalia D; Muresan, Ximena M; Belmonte, Giuseppe; Cervellati, Franco; Sticozzi, Claudia; Pecorelli, Alessandra; Miracco, Clelia; Marchini, Timoteo; Evelson, Pablo; Valacchi, Giuseppe

    2016-01-01

    Epidemiological studies suggest a correlation between increased airborne particulate matter (PM) and adverse health effects. The mechanisms of PM-health effects are believed to involve oxidative stress and inflammation. To evaluate the ability of PM promoting skin tissue damage, one of the main organs exposed to outdoor pollutants, we analyzed the effect of concentrated ambient particles (CAPs) in a reconstructed human epidermis (RHE) model. RHE tissues were exposed to 25 or 100 µg/ml CAPs for 24 or 48 h. Data showed that RHE seems to be more susceptible to CAPs-induced toxicity after 48 h exposure than after 24 h. We found a local reactive O(2) species (ROS) production increase generated from metals present on the particle, which contributes to lipids oxidation. Furthermore, as a consequence of altered redox status, NFkB nucleus translocation was increase upon CAPs exposure, as well as cyclooxygenase 2 and cytochrome P450 levels, which may be involved in the inflammatory response initiated by PM. CAPs also triggered an apoptotic process in skin. Surprisingly, by transition electron microscopy analysis we showed that CAPs were able to penetrate skin tissues. These findings contribute to the understanding of the cutaneous pathophysiological mechanisms initiated by CAPs exposure, where oxidative stress and inflammation may play predominant roles. PMID:26507108

  18. Generation of acoustic rogue waves in dusty plasmas through three-dimensional particle focusing by distorted waveforms

    Science.gov (United States)

    Tsai, Ya-Yi; Tsai, Jun-Yi; I, Lin

    2016-06-01

    Rogue waves--rare uncertainly emerging localized events with large amplitudes--have been experimentally observed in many nonlinear wave phenomena, such as water waves, optical waves, second sound in superfluid He II (ref. ) and ion acoustic waves in plasmas. Past studies have mainly focused on one-dimensional (1D) wave behaviour through modulation instabilities, and to a lesser extent on higher-dimensional behaviour. The question whether rogue waves also exist in nonlinear 3D acoustic-type plasma waves, the kinetic origin of their formation and their correlation with surrounding 3D waveforms are unexplored fundamental issues. Here we report the direct experimental observation of dust acoustic rogue waves in dusty plasmas and construct a picture of 3D particle focusing by the surrounding tilted and ruptured wave crests, associated with the higher probability of low-amplitude holes for rogue-wave generation.

  19. Optimal placement of distributed generation units in distribution systems via an enhanced multi-objective particle swarm optimization algorithm

    Institute of Scientific and Technical Information of China (English)

    Shan CHENG; Min-you CHEN; Rong-jong WAI; Fang-zong WANG

    2014-01-01

    This paper deals with the optimal placement of distributed generation (DG) units in distribution systems via an enhanced multi-objective particle swarm optimization (EMOPSO) algorithm. To pursue a better simulation of the reality and provide the designer with diverse alternative options, a multi-objective optimization model with technical and operational con-straints is constructed to minimize the total power loss and the voltage fluctuation of the power system simultaneously. To enhance the convergence of MOPSO, special techniques including a dynamic inertia weight and acceleration coefficients have been inte-grated as well as a mutation operator. Besides, to promote the diversity of Pareto-optimal solutions, an improved non-dominated crowding distance sorting technique has been introduced and applied to the selection of particles for the next iteration. After verifying its effectiveness and competitiveness with a set of well-known benchmark functions, the EMOPSO algorithm is em-ployed to achieve the optimal placement of DG units in the IEEE 33-bus system. Simulation results indicate that the EMOPSO algorithm enables the identification of a set of Pareto-optimal solutions with good tradeoff between power loss and voltage sta-bility. Compared with other representative methods, the present results reveal the advantages of optimizing capacities and loca-tions of DG units simultaneously, and exemplify the validity of the EMOPSO algorithm applied for optimally placing DG units.

  20. Investigation of the particle size distribution of the ejected material generated during the single femtosecond laser pulse ablation of aluminium

    International Nuclear Information System (INIS)

    Highlights: • Single 50 fs laser pulse ablation of an aluminium target in vacuum is investigated in our experiments. • Nanoparticles with large radii of several hundred nanometers are observed. • The nanoparticles are most likely from the mechanical tensile stress relaxation. - Abstract: Single femtosecond laser pulses are employed to ablate an aluminium target in vacuum, and the particle size distribution of the ablated material deposited on a mica substrate is examined with atomic force microscopy (AFM). The recorded AFM images show that these particles have a mean radius of several tens of nanometres. It is also determined that the mean radius of these deposited nanoparticles increases when the laser fluence at the aluminium target increases from 0.44 J/cm2 to 0.63 J/cm2. The mechanism of the laser-induced nanoparticle generation is thought to be photomechanical tensile stress relaxation. Raman spectroscopy measurements confirm that the nanoparticles thus produced have the same structure as the bulk aluminium

  1. Airborne radioactive contamination monitoring

    International Nuclear Information System (INIS)

    Current technologies for the detection of airborne radioactive contamination do not provide real-time capability. Most of these techniques are based on the capture of particulate matter in air onto filters which are then processed in the laboratory; thus, the turnaround time for detection of contamination can be many days. To address this shortcoming, an effort is underway to adapt LRAD (Long-Range-Alpha-Detection) technology for real-time monitoring of airborne releases of alpa-emitting radionuclides. Alpha decays in air create ionization that can be subsequently collected on electrodes, producing a current that is proportional to the amount of radioactive material present. Using external fans on a pipe containing LRAD detectors, controlled samples of ambient air can be continuously tested for the presence of radioactive contamination. Current prototypes include a two-chamber model. Sampled air is drawn through a particulate filter and then through the first chamber, which uses an electrostatic filter at its entrance to remove ambient ionization. At its exit, ionization that occurred due to the presence of radon is collected and recorded. The air then passes through a length of pipe to allow some decay of short-lived radon species. A second chamber identical to the first monitors the remaining activity. Further development is necessary on air samples without the use of particulate filtering, both to distinguish ionization that can pass through the initial electrostatic filter on otherwise inert particulate matter from that produced through the decay of radioactive material and to separate both of these from the radon contribution. The end product could provide a sensitive, cost-effective, real-time method of determining the presence of airborne radioactive contamination

  2. Airborne field strength monitoring

    Directory of Open Access Journals (Sweden)

    J. Bredemeyer

    2007-06-01

    Full Text Available In civil and military aviation, ground based navigation aids (NAVAIDS are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000 by the International Civil Aviation Organization (ICAO. One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz, the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA accelerated method of moments (MoM using a complex geometric model of the aircraft. First results will be presented in this paper.

  3. Airborne silica levels in an urban area

    International Nuclear Information System (INIS)

    In order to evaluate the exposure levels of the general population we studied the concentrations of silica particles in the inhalable particulate fraction (PM10) in different meteorological-climate periods in an urban area of Rome. In order to determine the concentration and the granulometric spectrum of silica particles, PM10 sampled by a cascade impactor was analysed by X-ray diffractometry (XRD) and by scanning electron microscopy equipped with a thin-window system for X-ray microanalysis (SEM/EDX). Over the period September 2004-October 2005 the abundance of silica particles as evaluated by SEM/EDX ranged from 1.6 to 10.4% of the total PM10 particulate, with a weight concentration of free crystalline silica, evaluated by XRD, in the range 0.25-2.87 μg/m3. The mean diameter of silica particles ranged from 0.3 to 10.5 μm, with more than 87% of particles having a diameter of less than 2.5 μm. The correlations between SEM/EDX and XRD data seem to suggest that the airborne silica particles in the urban location studied were mainly in the form crystalline silica. A strong relationship was found between the meteorological-climate conditions and the concentration level of free crystalline silica. This result suggests that the Southern winds from the Sahara desert carry an important amount of silica particles into Mediterranean Europe

  4. Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Patrik T., E-mail: patrik.nilsson@design.lth.se; Isaxon, Christina [Lund University, Ergonomics and Aerosol Technology (Sweden); Eriksson, Axel C. [Lund University, Nuclear Physics (Sweden); Messing, Maria E. [Lund University, Solid State Physics (Sweden); Ludvigsson, Linus; Rissler, Jenny [Lund University, Ergonomics and Aerosol Technology (Sweden); Hedmer, Maria; Tinnerberg, Håkan [Lund University, Division of Occupational and Environmental Medicine, Department of Laboratory Medicine (Sweden); Gudmundsson, Anders [Lund University, Ergonomics and Aerosol Technology (Sweden); Deppert, Knut [Lund University, Solid State Physics (Sweden); Bohgard, Mats; Pagels, Joakim H. [Lund University, Ergonomics and Aerosol Technology (Sweden)

    2013-11-15

    Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time- and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02–10 μm, were dominated by large agglomerates (1–5 μm). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (10{sup 3}–10{sup 5}/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments.

  5. Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

    International Nuclear Information System (INIS)

    Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time- and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02–10 μm, were dominated by large agglomerates (1–5 μm). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (103–105/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments

  6. Compositae dermatitis from airborne parthenolide

    DEFF Research Database (Denmark)

    Paulsen, E; Christensen, Lars Porskjær; Andersen, Klaus Ejner

    2007-01-01

    BACKGROUND: Compositae dermatitis confined to exposed skin has often been considered on clinical grounds to be airborne. Although anecdotal clinical and plant chemical reports suggest true airborne allergy, no proof has been procured. Feverfew (Tanacetum parthenium) is a European Compositae plant...

  7. Aerosols generated by spills of viscous solutions and slurries

    International Nuclear Information System (INIS)

    Safety assessments and environmental impact statements for nuclear fuel cycle facilities require an estimate of potential airborne releases caused by accidents. Aerosols generated by accidents are being investigated by Pacific Northwest Laboratory to develop methods for estimating source terms from these accidents. Experiments were run by spilling viscous solutions and slurries to determine the mass and particle-size distribution of the material made airborne. In all cases, 1 L of solution was spilled from a height of 3 m. Aqueous solutions of sucrose (0 to 56%) gave a range of viscosities from 1.3 to 46 cp. The percent of spill mass made airborne from the spills of these solutions ranged from 0.001 to 0.0001. The mass of particles made airborne decreased as solution viscosity increased. Slurry loading ranged from 25 to 51% total solids. The maximum source airborne (0.0046 wt %) occurred with the slurry that had the lightest loading of soluble solids. The viscosity of the carrying solution also had an impact on the source term from spilling slurries. The effect of surface tension on the source term was examined in two experiments. Surface tension was halved in these spills by adding a surfactant. The maximum weight percent airborne from these spills was 0.0045, compared to 0.003 for spills with twice the surface tension. The aerodynamic mass medium diameters for the aerosols produced by spills of the viscous solutions, slurries, and low surface tension liquids ranged from 0.6 to 8.4 μm, and the geometric standard deviation ranged from 3.8 to 28.0

  8. Spatial distributions of airborne dust in a cows barn exposed to influence of different ventilation rates

    OpenAIRE

    Topisirović G.; Petrović D.V.; Maletić R.

    2013-01-01

    Information on the concentration of dust particles is an important microclimate parameter that characterizes the local environmental quality of each livestock building. Increased concentration of dust particles primarily affects the indoor air quality and, consequently, the animal and workers health. Among many others, ventilation rate is a vital parameter that controls the spatial distribution of airborne dust particles in livestock buildings. This was the...

  9. Influence of instruments performance and material properties on exposure assessment of airborne engineered nanomaterials

    DEFF Research Database (Denmark)

    Levin, Marcus

    particle number concentration. Measured size distributions with particle modes above 150 nm should not be deemed reliable as they might arise from misclassification of larger size particles. 4) That current methods for real-time measurement of lung-deposited surface area concentration for airborne...

  10. Airborne transmission of lyssaviruses.

    Science.gov (United States)

    Johnson, N; Phillpotts, R; Fooks, A R

    2006-06-01

    In 2002, a Scottish bat conservationist developed a rabies-like disease and subsequently died. This was caused by infection with European bat lyssavirus 2 (EBLV-2), a virus closely related to Rabies virus (RABV). The source of this infection and the means of transmission have not yet been confirmed. In this study, the hypothesis that lyssaviruses, particularly RABV and the bat variant EBLV-2, might be transmitted via the airborne route was tested. Mice were challenged via direct introduction of lyssavirus into the nasal passages. Two hours after intranasal challenge with a mouse-adapted strain of RABV (Challenge Virus Standard), viral RNA was detectable in the tongue, lungs and stomach. All of the mice challenged by direct intranasal inoculation developed disease signs by 7 days post-infection. Two out of five mice challenged by direct intranasal inoculation of EBLV-2 developed disease between 16 and 19 days post-infection. In addition, a simple apparatus was evaluated in which mice could be exposed experimentally to infectious doses of lyssavirus from an aerosol. Using this approach, mice challenged with RABV, but not those challenged with EBLV-2, were highly susceptible to infection by inhalation. These data support the hypothesis that lyssaviruses, and RABV in particular, can be spread by airborne transmission in a dose-dependent manner. This could present a particular hazard to personnel exposed to aerosols of infectious RABV following accidental release in a laboratory environment. PMID:16687600

  11. Airborne monitoring system

    International Nuclear Information System (INIS)

    A complete system for tracking, mapping, and performing a composition analysis of a radioactive plume and contaminated area was developed at the NRCN. The system includes two major units : An airborne unit for monitoring and a ground station for analyzing. The airborne unit is mounted on a helicopter and includes file following. Four radiation sensor, two 2'' x 2'' Nal (Tl) sensors horizontally separated by lead shield for mapping and spectroscopy, and two Geiger Mueller (GM) tubes as part of the safety system. A multichannel analyzer card is used for spectroscopy. A navigation system, based on GPS and a barometric altitude meter, is used to locate the plume or ground data. The telemetry system, consisting of a transceiver and a modem, transfers all the data in real time to the ground station. An industrial PC (Field Works) runs a dedicated C++ Windows application to manage the acquired data. An independent microprocessor based backup system includes a recorder, display, and key pad. The ground station is based on an industrial PC, a telemetry system, a color printer and a modem to communicate with automatic meteorology stations in the relevant area. A special software controls the ground station. Measurement results are analyzed in the ground station to estimate plume parameters including motion, location, size, velocity, and perform risk assessment. (authors)

  12. A comparison of hydroxyl radical and hydrogen peroxide generation in ambient particle extracts and laboratory metal solutions

    Science.gov (United States)

    Shen, Huiyun; Anastasio, Cort

    2012-01-01

    Generation of reactive oxygen species (ROS) - including superoxide ( rad O 2-), hydrogen peroxide (HOOH), and hydroxyl radical ( rad OH) - has been suggested as one mechanism underlying the adverse health effects caused by ambient particulate matter (PM). In this study we compare HOOH and rad OH production from fine and coarse PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California, as well as from laboratory solutions containing dissolved copper or iron. Samples were extracted in a cell-free, phosphate-buffered saline (PBS) solution containing 50 μM ascorbate (Asc). In our laboratory solutions we find that Cu is a potent source of both HOOH and rad OH, with approximately 90% of the electrons that can be donated from Asc ending up in HOOH and rad OH after 4 h. In contrast, in Fe solutions there is no measurable HOOH and only a modest production of rad OH. Soluble Cu in the SJV PM samples is also a dominant source of HOOH and rad OH. In both laboratory copper solutions and extracts of ambient particles we find much more production of HOOH compared to rad OH: e.g., HOOH generation is approximately 30-60 times faster than rad OH generation. The formation of HOOH and rad OH are positively correlated, with roughly 3% and 8% of HOOH converted to rad OH after 4 and 24 h of extraction, respectively. Although the SJV PM produce much more HOOH than rad OH, since rad OH is a much stronger oxidant it is unclear which species might be more important for oxidant-mediated toxicity from PM inhalation.

  13. Development of airborne remote sensing data assimilation system

    International Nuclear Information System (INIS)

    In this paper, an airborne remote sensing data assimilation system for China Airborne Remote Sensing System is introduced. This data assimilation system is composed of a land surface model, data assimilation algorithms, observation data and fundamental parameters forcing the land surface model. In this data assimilation system, Variable Infiltration Capacity hydrologic model is selected as the land surface model, which also serves as the main framework of the system. Three-dimensional variation algorithm, four-dimensional variation algorithms, ensemble Kalman filter and Particle filter algorithms are integrated in this system. Observation data includes ground observations and remotely sensed data. The fundamental forcing parameters include soil parameters, vegetation parameters and the meteorological data

  14. Using Airborne SAR Interferometry to Measure the Elevation of a Greenland Ice Cap

    DEFF Research Database (Denmark)

    Dall, Jørgen; Keller, K.; Madsen, S.N.;

    2000-01-01

    A digital elevation model (DEM) of an ice cap in Greenland has been generated from airborne SAR interferometry data, calibrated with a new algorithm, and compared with airborne laser altimetry profiles and carrier-phase differential GPS measurements of radar reflectors deployed on the ice cap. The...

  15. Topography and Penetration of the Greenland Ice Sheet Measured with Airborne SAR Interferometry

    DEFF Research Database (Denmark)

    Dall, Jørgen; Madsen, Søren Nørvang; Keller, K.;

    2001-01-01

    A digital elevation model (DEM) of the Geikie ice sap in East Greenland has been generated from interferometric C-band synthetic aperture radar (SAR) data acquired with the airborne EMISAR system. GPS surveyed radar reflectors and an airborne laser altimeter supplemented the experiment. The accur...

  16. Single Scattering Albedo Monitor for Airborne Particulates

    Science.gov (United States)

    Onasch, Timothy; Massoli, Paola; Kebabian, Paul; Hills, Frank; Bacon, Fred; Freedman, Andrew

    2015-04-01

    We describe a robust, compact, field deployable instrument (the CAPS PMssa) that simultaneously measures airborne particle light extinction and scattering coefficients and thus the single scattering albedo (SSA) on the same sample volume. With an appropriate change in mirrors and light source, measurements have been made at wavelengths ranging from 450 to 780 nm. The extinction measurement is based on cavity attenuated phase shift (CAPS) techniques as employed in the CAPS PMex particle extinction monitor; scattering is measured using a integrating nephelometry by incorporating a Lambertian integrating sphere within the sample cell. The scattering measurement is calibrated using the extinction measurement. Measurements using ammonium sulfate particles of various sizes indicate that the response of the scattering channel with respect to measured extinction is linear to within 1% up to 1000 Mm-1 and can be extended further (4000 Mm-1) with additional corrections. The precision in both measurement channels is less than 1 Mm-1 (1s, 1σ). The truncation effect in the scattering channel, caused by light lost at extreme forward/backward scattering angles, was measured as a function of particle size using monodisperse polystyrene latex particles (n=1.59). The results were successfully fit using a simple geometric model allowing for reasonable extrapolation to a given wavelength, particle index of refraction and particle size distribution, assuming spherical particles. For sub-micron sized particles, the truncation corrections are comparable to those reported for commercial nephelometers. Measurements of the optical properties of ambient aerosol indicate that the values of the SSA of these particles measured with this instrument (0.91±0.03) using scattering and extinction agreed within experimental uncertainty with those determined using extinction measured by this instrument and absorption measured using a Multi-Angle Absorption Spectrometer (0.89±0.03) where the

  17. MITAS: multisensor imaging technology for airborne surveillance

    Science.gov (United States)

    Thomas, John D.

    1991-08-01

    MITAS, a unique and low-cost solution to the problem of collecting and processing multisensor imaging data for airborne surveillance operations has been developed, MITAS results from integrating the established and proven real-time video processing, target tracking, and sensor management software of TAU with commercially available image exploitation and map processing software. The MITAS image analysis station (IAS) supports airborne day/night reconnaissance and surveillance missions involving low-altitude collection platforms employing a suite of sensors to perform reconnaissance functions against a variety of ground and sea targets. The system will detect, locate, and recognize threats likely to be encountered in support of counternarcotic operations and in low-intensity conflict areas. The IAS is capable of autonomous, near real-time target exploitation and has the appropriate communication links to remotely located IAS systems for more extended analysis of sensor data. The IAS supports the collection, fusion, and processing of three main imaging sensors: daylight imagery (DIS), forward looking infrared (FLIR), and infrared line scan (IRLS). The MITAS IAS provides support to all aspects of the airborne surveillance mission, including sensor control, real-time image enhancement, automatic target tracking, sensor fusion, freeze-frame capture, image exploitation, target data-base management, map processing, remote image transmission, and report generation.

  18. Airborne Tactical Free-Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, Roy; Neil, George

    2007-02-01

    The goal of 100 kilowatts (kW) of directed energy from an airborne tactical platform has proved challenging due to the size and weight of most of the options that have been considered. However, recent advances in Free-Electron Lasers appear to offer a solution along with significant tactical advantages: a nearly unlimited magazine, time structures for periods from milliseconds to hours, radar like functionality, and the choice of the wavelength of light that best meets mission requirements. For an Airborne Tactical Free-Electron Laser (ATFEL) on a platforms such as a Lockheed C-130J-30 and airships, the two most challenging requirements, weight and size, can be met by generating the light at a higher harmonic, aggressively managing magnet weights, managing cryogenic heat loads using recent SRF R&D results, and using FEL super compact design concepts that greatly reduce the number of components. The initial R&D roadmap for achieving an ATFEL is provided in this paper. Performing this R&D is expected to further reduce the weight, size and power requirements for the FELs the Navy is currently developing for shipboard applications, as well as providing performance enhancements for the strategic airborne MW class FELs. The 100 kW ATFEL with its tactical advantages may prove sufficiently attractive for early advancement in the queue of deployed FELs.

  19. Surface modification of amorphous nanosilica particles suppresses nanosilica-induced cytotoxicity, ROS generation, and DNA damage in various mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tokuyuki [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Yoshioka, Yasuo, E-mail: yasuo@phs.osaka-u.ac.jp [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Matsuyama, Keigo; Nakazato, Yasutaro; Tochigi, Saeko; Hirai, Toshiro; Kondoh, Sayuri [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nagano, Kazuya [Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); Abe, Yasuhiro [Cancer Biology Research Center, Sanford Research/USD, 2301 E. 60th Street N, Sioux Falls, SD 57104 (United States); Kamada, Haruhiko; Tsunoda, Shin-ichi [Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nabeshi, Hiromi [Division of Foods, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Yoshikawa, Tomoaki [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Tsutsumi, Yasuo, E-mail: ytsutsumi@phs.osaka-u.ac.jp [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer There is increasing concern regarding the potential health risks of nanomaterials. Black-Right-Pointing-Pointer We evaluated the effect of surface properties of nanomaterials on cellular responses. Black-Right-Pointing-Pointer We showed that the surface properties play an important in determining its safety. Black-Right-Pointing-Pointer These data provide useful information for producing safer nanomaterials. -- Abstract: Recently, nanomaterials have been utilized in various fields. In particular, amorphous nanosilica particles are increasingly being used in a range of applications, including cosmetics, food technology, and medical diagnostics. However, there is concern that the unique characteristics of nanomaterials might induce undesirable effects. The roles played by the physical characteristics of nanomaterials in cellular responses have not yet been elucidated precisely. Here, by using nanosilica particles (nSPs) with a diameter of 70 nm whose surface was either unmodified (nSP70) or modified with amine (nSP70-N) or carboxyl groups (nSP70-C), we examined the relationship between the surface properties of nSPs and cellular responses such as cytotoxicity, reactive oxygen species (ROS) generation, and DNA damage. To compare the cytotoxicity of nSP70, nSP70-N, or nSP70-C, we examined in vitro cell viability after nSP treatment. Although the susceptibility of each cell line to the nSPs was different, nSP70-C and nSP70-N showed lower cytotoxicity than nSP70 in all cell lines. Furthermore, the generation of ROS and induction of DNA damage in nSP70-C- and nSP70-N-treated cells were lower than those in nSP70-treated cells. These results suggest that the surface properties of nSP70 play an important role in determining its safety, and surface modification of nSP70 with amine or carboxyl groups may be useful for the development of safer nSPs. We hope that our results will contribute to the development of safer nanomaterials.

  20. Surface modification of amorphous nanosilica particles suppresses nanosilica-induced cytotoxicity, ROS generation, and DNA damage in various mammalian cells

    International Nuclear Information System (INIS)

    Highlights: ► There is increasing concern regarding the potential health risks of nanomaterials. ► We evaluated the effect of surface properties of nanomaterials on cellular responses. ► We showed that the surface properties play an important in determining its safety. ► These data provide useful information for producing safer nanomaterials. -- Abstract: Recently, nanomaterials have been utilized in various fields. In particular, amorphous nanosilica particles are increasingly being used in a range of applications, including cosmetics, food technology, and medical diagnostics. However, there is concern that the unique characteristics of nanomaterials might induce undesirable effects. The roles played by the physical characteristics of nanomaterials in cellular responses have not yet been elucidated precisely. Here, by using nanosilica particles (nSPs) with a diameter of 70 nm whose surface was either unmodified (nSP70) or modified with amine (nSP70-N) or carboxyl groups (nSP70-C), we examined the relationship between the surface properties of nSPs and cellular responses such as cytotoxicity, reactive oxygen species (ROS) generation, and DNA damage. To compare the cytotoxicity of nSP70, nSP70-N, or nSP70-C, we examined in vitro cell viability after nSP treatment. Although the susceptibility of each cell line to the nSPs was different, nSP70-C and nSP70-N showed lower cytotoxicity than nSP70 in all cell lines. Furthermore, the generation of ROS and induction of DNA damage in nSP70-C- and nSP70-N-treated cells were lower than those in nSP70-treated cells. These results suggest that the surface properties of nSP70 play an important role in determining its safety, and surface modification of nSP70 with amine or carboxyl groups may be useful for the development of safer nSPs. We hope that our results will contribute to the development of safer nanomaterials.

  1. Ultrafine Condensation Particle Counter Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-01

    The Model 3776 Ultrafine Condensation Particle Counter (UCPC; pictured in Appendix A) is designed for researchers interested in airborne particles smaller than 20 nm. With sensitivity to particles down to 2.5 nm in diameter, this UCPC is ideally suited for atmospheric and climate research, particle formation and growth studies, combustion and engine exhaust research, and nanotechnology research.

  2. Airborne Cloud Computing Environment (ACCE)

    Science.gov (United States)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  3. Influence of negative pressurization on airborne microbial and radon levels

    Energy Technology Data Exchange (ETDEWEB)

    Kalliokoski, P.; Korhonen, P.; Kokotti, H.; Pasanen, A.L.; Rautiala, S.; Rantamaeki, J.

    1999-07-01

    The negative pressure inside a building is the main driving force for the entry of both radon and fungal spores. This study was conducted to test the suitability of depressurization to facilitate simultaneously the detection of fungal growth within the lower parts of building envelope and the risk of radon entry. Pressure difference was increased in three steps to 24--28 Pa in two wooden buildings known to suffer from long-term water damages. At the end, pulses of negative pressure were generated. Airborne viable fungal counts, radon and particle counts were followed during the tests together with the ventilation rate and particle count. The absolute concentrations of the impurities studied did not increase significantly or even decreased during the tests due to enhanced ventilation. However, when the increase in the ventilation rate was taken into consideration it was found that the entry rate of all the contaminants increased. The changes were larger in the tighter building where the radon entry rate increased systematically with the pressure difference reaching finally 13.8-fold level compared to the initial value. In the less tight building, the corresponding highest radon entry rate ratio was 9.5. Very large increases, up to 42-fold, were observed in the viable spore count ratio in the tighter building during the tests. In the leaky building, the changes were again considerably smaller; the maximum ratio was 4.2. Increases in particle emissions were smaller than those observed in fungal counts. The pulses were less effective than continuous depressurization. The results show that negative pressurization can be used to increase the release of fungal spores in order to detect hidden fungal growth. This kind of test is especially effective if there are no major leaks in the clean part of the building envelope. The method allows simultaneous rapid checking of need for radon mitigation.

  4. Dispersion model for airborne particulates inside a building

    International Nuclear Information System (INIS)

    An empirical model has been developed for the spread of airborne radioactive particles after they are released inside a building. The model has been useful in performing safety analyses of actinide materials facilities at the Savannah River Plant (SRP). These facilities employ the multiple-air-zone concept; that is, ventilation air flows from rooms or areas of least radioactive material hazard, through zones of increasing hazard, to a treatment system. A composite of the data for dispersion of airborne activity during 12 actual case incidents at SRP forms the basis for this model. These incidents occurred during approximately 90 plant-years of experience at SRP with the chemical and metallurgical processing of purified neptunium and plutonium after their recovery from irradiated uranium. The model gives ratios of the airborne activity concentrations in rooms and corridors near the site of the release. The multiple-air-zone concept has been applied to many designs of nuclear facilities as a safety feature to limit the spread of airborne activity from a release. The model illustrates the limitations of this concept: it predicts an apparently anomalous behavior of airborne particulates; namely, a small migration against the flow of the ventilation air

  5. Wear Particles Impair Antimicrobial Activity Via Suppression of Reactive Oxygen Species Generation and ERK1/2 Phosphorylation in Activated Macrophages.

    Science.gov (United States)

    Chen, Weishen; Li, Ziqing; Guo, Ying; Zhou, Yuhuan; Zhang, Yangchun; Luo, Guotian; Yang, Xing; Li, Chaohong; Liao, Weiming; Sheng, Puyi

    2015-01-01

    Implant-related infection (IRI) is closely related to the local immunity of peri-implant tissues. The generation of reactive oxygen species (ROS) in activated macrophages plays a prominent role in the innate immune response. In previous studies, we indicated that implant wear particles promote endotoxin tolerance by decreasing the release of proinflammatory cytokines. However, it is unclear whether ROS are involved in the damage of the local immunity of peri-implant tissues. In the present study, we assessed the mechanism of local immunosuppression using titanium (Ti) particles and/or lipopolysaccharide (LPS) to stimulate RAW 264.7 cells. The results indicate that the Ti particles induced the generation of a moderate amount of ROS through nicotinamide adenine dinucleotide phosphate oxidase-1, but not through catalase. Pre-exposure to Ti particles inhibited ROS generation and extracellular-regulated protein kinase activation in LPS-stimulated macrophages. These findings indicate that chronic stimulation by Ti particles may lead to a state of oxidative stress and persistent inflammation, which may result in the attenuation of the immune response of macrophages to bacterial components such as LPS. Eventually, immunosuppression develops in peri-implant tissues, which may be a risk factor for IRI. PMID:25577344

  6. Ultrafine particles in the atmosphere

    CERN Document Server

    Brown, L M; Harrison, R M; Maynard, A D; Maynard, R L

    2003-01-01

    Following the recognition that airborne particulate matter, even at quite modest concentrations, has an adverse effect on human health, there has been an intense research effort to understand the mechanisms and quantify the effects. One feature that has shone through is the important role of ultrafine particles as a contributor to the adverse effects of airborne particles. In this volume, many of the most distinguished researchers in the field provide a state-of-the-art overview of the scientific and medical research on ultrafine particles. Contents: Measurements of Number, Mass and Size Distr

  7. Characterisation of airborne dust in a gold mine

    International Nuclear Information System (INIS)

    Samples of airborne dust were collected from a gold mine using a single orifice cascade impactor. The size fractionated dust samples were analysed by Particle Induced X-ray Emission (PIXE) and Electron Probe X-ray Micro-Analysis (EPXMA). Results on chemical composition of the sub-micron, inhalable dust were obtained. In addition ot quartz dust, a large fraction consisted of chlorine containing particles. The filter grade efficiency of a spray cooling chamber was calculated as a function of particle size

  8. Airborne Electro-Optical Sensor Simulation System. Final Report.

    Science.gov (United States)

    Hayworth, Don

    The total system capability, including all the special purpose and general purpose hardware comprising the Airborne Electro-Optical Sensor Simulation (AEOSS) System, is described. The functional relationship between hardware portions is described together with interface to the software portion of the computer image generation. Supporting rationale…

  9. Simulation of diffusion-induced stress using reconstructed electrodes particle structures generated by micro/nano-CT

    International Nuclear Information System (INIS)

    Highlights: ► The microstructure of LIB electrodes was obtained by X-ray micro/nano-CT. ► We studied diffusion-induced stresses based on realistic 3D microstructures. ► Stresses depend on geometric characteristics of electrode particle. ► Stresses in a real particle are much higher than those in a spherical particle. - Abstract: Lithium ion batteries experience diffusion-induced stresses during charge and discharge processes which can cause electrode failure in the form of fracture. Previous diffusion-induced stress models and simulations are mainly based on simple active material particle structures, such as spheres and ellipsoids. However, the simple structure model cannot reveal the stress development in a real complex lithium ion battery electrode. In this paper, we studied the diffusion-induced stresses numerically based on a realistic morphology of reconstructed particles during the lithium ion intercalation process. The morphology of negative and positive active materials of a lithium ion battery was determined using X-ray micro/nano computed tomography technology. Diffusion-induced stresses were simulated at different C rates under galvonostatic conditions and compared with spherical particles. The simulation results show that the intercalation stresses of particles depend on their geometric characteristics. The highest von Mises stress and Tresca stress in a real particle are several times higher than the stresses in a spherical particle with the same volume.

  10. Airborne Dust, "The Good Guy or the Bad Guy": How Much do We Know?

    Science.gov (United States)

    Tsay, Si-Chee

    2010-01-01

    Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena -African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth's ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton -the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth. Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such

  11. Arcing and rf signal generation during target irradiation by a high-energy, pulsed neutral particle beam

    International Nuclear Information System (INIS)

    We present a theory describing the dynamics of arc discharges in bulk dielectric materials on board space-based vehicles. Such ''punch-through'' arcs can occur in target satellites irradiated by high-energy (250 MeV), pulsed (100 mA x 10 ms) neutral particle beams. We treat the arc as a capacitively limited avalanche current in the target dielectric material, and we find expressions for the arc duration, charge transport, currents, and discharge energy. These quantities are adjusted to be consistent with known scaling laws for the area of charge depleted by the arc. After a brief account of the statistical distribution of voltages at which the arc starts and stops, we calculate the signal strength and frequency spectrum of the electromagnetic radiation broadcast by the arc. We find that arcs from thick (/similar to/1 cm) targets can generate rf signals detectable up to 1000 km from the target, bu a radio receiver operating at frequency 80 MHz, bandwidth 100 kHz, and detection threshold -105 dBm. These thick-target arc signals are 10 to 20 dB above ambient noise at the receiver, and they provide target hit assessment if the signal spectrum can be sampled at several frequencies in the nominal range 30-200 MHz. Thin-target (/similar to/1 mm) arc signals are much weaker, but when they are detecable in conjunction with thick-target signals, target discrimination is possible by comparing the signal frequency spectra. 24 refs., 12 figs

  12. The Effect of Nanoclay on Dust Generation during Drilling of PA6 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Sophia Sachse

    2012-01-01

    Full Text Available During the past decade, polymer nanocomposites have emerged as a novel and rapidly developing class of materials and attracted considerable investment in research and development worldwide. However, there is currently a lack of information available in the literature on the nano and ultrafine particle emission rates from these materials. In this paper, influence of nanoclay on mechanical drilling of PA6 composites, in terms of dust generation, has been reported. With the help of real-time characterization, submicrometer-sized particles (5.6–512 nm, size distribution, and number concentration emitted from polyamide 6/nanoclay composites during mechanical drilling are studied. Total particle concentration for the PA6/nanoclay composites was 20,000 cm−3, while unreinforced panel measured a total concentration of approximately 400,000 cm−3. While the airborne particle concentration for the PA6/nanoclay composites was 20 times lower than for the PA6 matrix, the concentration of deposited nanoparticles doubled for the nanocomposite. The results clearly show that more particles in the size range between 175 and 350 nm are generated, during drilling of the nanocomposites, and these particles deposit in a shorter time. It is likely that the presence of nanoclay in some way retains the formation of high quantity of airborne particles and promotes particle deposition.

  13. Air sampling system for airborne surveys

    International Nuclear Information System (INIS)

    An air sampling system has been designed for installation on the Beechcraft King Air A-100 aircraft as a part of the Aerial Radiological Measuring System (ARMS). It is intended for both particle and whole gas sampling. The sampling probe is designed for isokinetic sampling and is mounted on a removable modified escape hatch cover, behind the co-pilot's seat, and extends about two feet forward of the hatch cover in the air stream lines. Directly behind the sampling probe inside the modified hatch cover is an expansion chamber, space for a 5-inch diameter filter paper cassette, and an optional four-stage cascade impactor for particle size distribution measurements. A pair of motors and blower pumps provide the necessary 0.5 atmosphere pressure across the type MSA 1106 B glass fiber filter paper to allow a flow rate of 50 cfm. The MSA 1106 B filter paper is designed to trap sub-micrometer particles with a high efficiency; it was chosen to enable a quantitative measurement of airborne radon daughters, one of the principal sources of background signals when radiological surveys are being performed. A venturi section and pressure gauges allow air flow rate measurements so that airborne contaminant concentrations may be quantified. A whole gas sampler capable of sampling a cubic meter of air is mounted inside the aircraft cabin. A nuclear counting system on board the aircraft provides capability for α, β and γ counting of filter paper samples. Design data are presented and types of survey missions which may be served by this system are described

  14. South African Airborne Operations

    Directory of Open Access Journals (Sweden)

    McGill Alexander

    2012-02-01

    Full Text Available Airborne operations entail the delivery of ground troops and their equipment by air to their area of operations. They can also include the subsequent support of these troops and their equipment by air. Historically, and by definition, this would encompass delivery by fixed-wing powered aircraft, by glider, by parachute or by helicopter. Almost any troops can be delivered by most of these means. However, the technical expertise and physical as well as psychological demands required by parachuting have resulted in specialist troops being selected and trained for this role. Some of the material advantages of using parachute troops, or paratroops, are: the enormous strategic reach provided by the long-distance transport aircraft used to convey them; the considerable payload which these aircraft are capable of carrying; the speed with which the parachute force can deploy; and the fact that no infrastructure such as airfields are required for their arrival. Perhaps most attractively to cash-strapped governments, the light equipment scales of parachute units’ makes them economical to establish and maintain. There are also less tangible advantages: the soldiers selected are invariably volunteers with a willingness or even desire to tackle challenges; their selection and training produces tough, confident and aggressive troops, psychologically geared to face superior odds and to function independently from other units; and their initiative and self-reliance combined with a high level of physical fitness makes them suitable for a number of different and demanding roles.

  15. Characterization and exposure measurement for indium oxide nanofibers generated as byproducts in the LED manufacturing environment.

    Science.gov (United States)

    Choi, Kwang-Min; An, Hee-Chul

    2016-01-01

    This article aimed to elucidate the physicochemical characteristics and exposure concentration of powder and airborne particles as byproducts generated from indium tin oxide thin film process by an electron beam evaporation method during maintenance in light-emitting diode manufacturing environment. The chemical composition, size, shape, and crystal structure of powder and airborne particles as byproducts were investigated using a scanning electron microscope equipped with energy dispersive spectrometer, and an X-ray diffractometer. The number and mass concentration measurements of airborne particles were performed by using an optical particle counter of direct-reading aerosol monitor and an inductively coupled plasma-mass spectrometry after sampling, respectively. The airborne particles are composed of oxygen and indium. On the other hand, the powder byproducts consist mostly of oxygen and indium, but tin was found as a minor component. The shapes of the airborne and powder byproducts were fiber type. The length and diameter of fibrous particles were approximately 500-2,000 nm and 30-50 nm, respectively. The powder byproducts indicated indium oxide nanofibers with a rhombohedral structure. On the other hand, the indium oxide used as a source material in the preparation of ITO target showed spherical morphology with a body-centered cubic structure, and it was the same as that of the pure crystalline indium oxide powder. During maintenance, the number concentrations ranged from 350-75,693 particles/ft(3), and arithmetic mean±standard deviation and geometric mean±geometric standard deviation were 11,624±15,547 and 4,846±4.12 particles/ft(3), respectively. Meanwhile, under the same conditions, the airborne mass concentrations of the indium based on respirable particle size (3.5 µm cut-point 50%) were 0.09-0.19 µg/m(3). Physicochemical characteristics of nanoparticle can affect toxicity so the fact that shape and crystal structure have changed is important. Thus

  16. Physico-chemical and optical properties of combustion-generated particles from coal-fired power plant, automobile and ship engine and charcoal kiln.

    Science.gov (United States)

    Kim, Hwajin

    2015-04-01

    Similarities and differences in physico-chemical and optical properties of combustion generated particles from various sources were investigated. Coal-fired power plant, charcoal kiln, automobile and ship engine were major sources, representing combustions of coal, biomass and two different types of diesel, respectively. Scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDX) equipped with both SEM and HRTEM were used for physico-chemical analysis. Light absorbing properties were assessed using a spectrometer equipped with an integrating sphere. Particles generated from different combustion sources and conditions demonstrate great variability in their morphology, structure and composition. From coal-fired power plant, both fly ash and flue gas were mostly composed of heterogeneously mixed mineral ash spheres, suggesting that the complete combustion was occurred releasing carbonaceous species out at high temperature (1200-1300 °C). Both automobile and ship exhausts from diesel combustions show typical features of soot: concentric circles comprised of closely-packed graphene layers. However, heavy fuel oil (HFO) combusted particles from ship exhaust demonstrate more complex compositions containing different morphology of particles other than soot, e.g., spherical shape of char particles composed of minerals and carbon. Even for the soot aggregates, particles from HFO burning have different chemical compositions; carbon is dominated but Ca (29.8%), S (28.7%), Na(1%), and Mg(1%) are contained, respectively which were not found from particles of automobile emission. This indicates that chemical compositions and burning conditions are significant to determine the fate of particles. Finally, from biomass burning, amorphous and droplet-like carbonaceous particles with no crystallite structure are observed and they are generally formed by the condensation of low volatile species at low

  17. Measurement of dark, particle-generated superoxide and hydrogen peroxide production and decay in the subtropical and temperate North Pacific Ocean

    Science.gov (United States)

    Roe, Kelly L.; Schneider, Robin J.; Hansel, Colleen M.; Voelker, Bettina M.

    2016-01-01

    Reactive oxygen species (ROS), which include the superoxide radical (O2-) and hydrogen peroxide (H2O2), are thought to be generated mostly through photochemical reactions and biological activity in seawater and can influence trace metal speciation in the ocean. This study reports the results of an intercomparison of two methods to measure particle-generated [O2-] in seawater samples, as well as measurements of particle-generated O2- and H2O2 concentrations, decay kinetics, and dark production rates in seawater samples at Station ALOHA and (O2- only) in the southern California Current Ecosystem. O2- was measured using two different methods relying on chemiluminescence detection. The first method measured the difference between steady-state [O2-] in filtered and unfiltered seawater, while the second method (standard method) measured O2- decay to baseline in freshly filtered seawater. Because both methods detected [O2-] relative to the background signal from filtered seawater, both should have measured [O2-] generated by particles (presumably biota). However, the O2- concentrations determined by the first method were always much smaller than those obtained from the second (standard) method. Follow-up laboratory and field experiments showed that the increased signal in the standard method was due to a filtration artifact that could neither be eliminated nor consistently accounted for under the tested conditions. We therefore recommend the first method for measuring particle-generated [O2-]. Measured by this method, Station ALOHA had particle-generated O2- concentrations that ranged from undetectable to 0.02 nM, with production rates less than 0.6 nM hr-1 and decay rate coefficients from 0.003 to 0.014 s-1. The southern California Current Ecosystem had particle-generated O2- concentrations that ranged from undetectable to 0.05 nM, with production rates up to 4.7 nM hr-1 and decay rate coefficients from 0.006 to 0.017 s-1. H2O2 concentrations were measured by

  18. Research on Block Adjustment of Airborne InSAR Images

    International Nuclear Information System (INIS)

    Airborne InSAR system and InSAR data processing algorithm have been one of the hot topics in the international SAR field. Geometric constraint relation of images is set up through airborne InSAR block adjustment, adjustment parameters are adjusted and refined, and the three-dimensional(3D) ground coordinates of tie-points(TPs) are solved according to least squares theory. The number of the ground control points(GCPs) is reduced. The airborne InSAR block adjustment experiment was done using self-developed Airborne InSAR Block Adjustment Software System. The 76 airborne InSAR images which are 0.5 m resolution and cover an area of 472 square kilometers generated a block of 4 strips and 19 rows with approximately 30% overlap between adjacent strips. The study site is located in in Jiangyou Sichuan province and characterized by a hilly topography. The result meets DEM and DOM mapping accuracy requirements at scale of 1:10000

  19. Assessment of airborne dust associated with chemical plant: A case study

    Directory of Open Access Journals (Sweden)

    Pattajoshi P

    2006-01-01

    Full Text Available The process of alumina production involves refining of bauxite ore into tri-hydrated alumina (Al2O3, 3H2O by chemical method followed by process of calcinations. This method possesses various kinds of dust hazards in its work environment amongst the people involved. Poor health of industrial employees in India is due to its occupational environment (Park & Park, 1970, which is a major concern now-a-days. Attempts have been made to recognize the potential sources of airborne dust and to assess the dust load upon exposed workers at different work sites of alumina plants by comparing the observations with the standard values called ′Threshold Limit Values′ (T.L.V. assigned by the international body ACGIH (American Conference of Governmental and Industrial Hygienists, USA, and also permissible exposure limit values prescribed in the second schedule Section F of Factories Act (Amendment, 1987. Alumina plant operation includes various physical operations like crushing, grinding, conveying, loading, transporting, etc., which generate finer particles. It can cause serious health hazards on inhalation, depending upon its size, shape, constituents and duration of exposure. Out of all these parameters, concentration of respirable fraction of airborne dust (0.5 to 5.0 micron size and its free silica content have been reported to cause lung fibrosis as well as occupational disorders. In the present study, attempts have been made to make a survey of respirable fraction of the airborne dust (that remains suspended in air for quite an appreciable time associated with various operations according to job profiles. It also outlines the probable control measures in order to provide a healthy working environment. Present work aims at identifying and evaluating the degree of workplace dust with special reference to respirable fraction and for recommending suitable suggestive control measures for an effective management of occupational environment.

  20. Dispersion model for airborne particulates inside a building

    International Nuclear Information System (INIS)

    An empirical model has been developed for the spread of airborne radioactive particles after they are released inside a building. The model has been useful in performing safety analyses of actinide materials facilities at the Savannah River Plant (SRP), operated for the US Department of Energy by the Du Pont Company. These facilities employ the multiple-air-zone concept; that is, ventilation air flows from rooms or areas of least radioactive material hazard, through zones of increasing hazard, to a treatment system. A composite of the data for dispersion of airborne activity during 12 actual case incidents at SRP forms the basis for this model. These incidents occurred during approximately 90 plant-years of experience at SRP with the chemical and metallurgical processing of purified neptunium and plutonium after their recovery from irradiated uranium. The model gives ratios of the airborne activity concentrations in rooms and corridors near the site of the release. All data are normalized to the data from the air sampler nearest the release point. The model can be applied in predicting airborne activity concentrations from particulate releases elsewhere, if the facility in question has similar features of floor plan, air velocity, and air flow direction. The multiple-air-zone concept has been applied to many designs of nuclear facilities as a safety feature to limit the spread of airborne activity from a release. The model illustrates the limitations of this concept: it predicts an apparently anomalous behavior of airborne particulates; namely, a small migration against the flow of the ventilation air. The following phenomena are suggested as possible mechanisms for this migration: eddy currents in the air flow; leaks of ventilation air between zones; open doors; movement of personnel during an incident; inadequate flow of ventilation air; and thermal gradients. 2 references, 12 figures, 4 tables