WorldWideScience

Sample records for aerosol material comparison

  1. International standard problem ISP37: VANAM M3 - A Multi compartment aerosol depletion test with hygroscopic aerosol material: comparison report

    International Nuclear Information System (INIS)

    Firnhaber, M.; Kanzleiter, T.F.; Schwarz, S.; Weber, G.

    1996-12-01

    This paper presents the results and assessment of the 'open' ISP37, which deals with the containment thermal-hydraulics and aerosol behavior during an unmitigated severe LWR accident with core melt-down and steam and aerosol release into the containment. Representatives of 22 organizations participated to the ISP37 using the codes CONTAIN, FIPLOC, MELCOR, RALOC, FUMO, MACRES, REMOVAL etc. The containment and aerosol behavior experiment VANAM M3 was selected as experimental comparison basis. The main phenomena investigated are the thermal behavior of a multi-compartment containment, e.g. pressure, temperature and the distribution and depletion of a soluble aerosol. The ISP37 has demonstrated that the codes used could calculate the thermal-hydraulic containment behavior in general with sufficient accuracy. But with respect to the needs of aerosol behavior analysis the accuracies, both analytical and experimental as well, for specific thermal-hydraulic variables should be improved. Although large progress has been made in the simulation of aerosol behavior in multi-compartment geometries the calculated local aerosol concentrations scatter widely. However, the aerosol source term to the environment is overestimated in general. The largest uncertainty concerning the aerosol results is caused by a limited number of thermal hydraulic variables like relative humidity, volume condensation rate and atmospheric flow rate. In some codes also a solubility model is missing

  2. Comparison of sodium aerosol codes

    International Nuclear Information System (INIS)

    Dunbar, I.H.; Fermandjian, J.; Bunz, H.; L'homme, A.; Lhiaubet, G.; Himeno, Y.; Kirby, C.R.; Mitsutsuka, N.

    1984-01-01

    Although hypothetical fast reactor accidents leading to severe core damage are very low probability events, their consequences are to be assessed. During such accidents, one can envisage the ejection of sodium, mixed with fuel and fission products, from the primary circuit into the secondary containment. Aerosols can be formed either by mechanical dispersion of the molten material or as a result of combustion of the sodium in the mixture. Therefore considerable effort has been devoted to study the different sodium aerosol phenomena. To ensure that the problems of describing the physical behaviour of sodium aerosols were adequately understood, a comparison of the codes being developed to describe their behaviour was undertaken. The comparison consists of two parts. The first is a comparative study of the computer codes used to predict aerosol behaviour during a hypothetical accident. It is a critical review of documentation available. The second part is an exercise in which code users have run their own codes with a pre-arranged input. For the critical comparative review of the computer models, documentation has been made available on the following codes: AEROSIM (UK), MAEROS (USA), HAARM-3 (USA), AEROSOLS/A2 (France), AEROSOLS/B1 (France), and PARDISEKO-IIIb (FRG)

  3. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Petroleo (IMP) and CENICA.

  4. Size distributions of aerosols produced from substitute materials by the Laskin cold DOP aerosol generator

    International Nuclear Information System (INIS)

    Hinds, W.; Macher, J.; First, M.W.

    1981-01-01

    Test aerosols of di(2-ethylhexyl)phthalate (DOP) produced by Laskin nozzle aerosol generators are widely used for in-place filter testing and respirator fit testing. Concern for the health effects of this material has led to a search for substitute materials for test aerosols. Aerosols were generated with a Laskin generator and diluted 6000-fold with clean air. Size distributions were measured for DOP, di(2-ethylhexyl)sebecate, polyethylene glycol, mineral oil, and corn oil aerosols with a PMS ASAS-X optical particle counter. Distributions were slightly bimodal with count median diameters from 0.22 to 0.30 μm. Size distributions varied little with aerosol material, operating pressure, or liquid level. Mineral oil and corn oil gave the best agreement with the DOP size distribution

  5. Pretest aerosol code comparisons for LWR aerosol containment tests LA1 and LA2

    International Nuclear Information System (INIS)

    Wright, A.L.; Wilson, J.H.; Arwood, P.C.

    1986-01-01

    The Light-Water-Reactor (LWR) Aerosol Containment Experiments (LACE) are being performed in Richland, Washington, at the Hanford Engineering Development Laboratory (HEDL) under the leadership of an international project board and the Electric Power Research Institute. These tests have two objectives: (1) to investigate, at large scale, the inherent aerosol retention behavior in LWR containments under simulated severe accident conditions, and (2) to provide an experimental data base for validating aerosol behavior and thermal-hydraulic computer codes. Aerosol computer-code comparison activities are being coordinated at the Oak Ridge National Laboratory. For each of the six LACE tests, ''pretest'' calculations (for code-to-code comparisons) and ''posttest'' calculations (for code-to-test data comparisons) are being performed. The overall goals of the comparison effort are (1) to provide code users with experience in applying their codes to LWR accident-sequence conditions and (2) to evaluate and improve the code models

  6. Organics, Meteoritic Material, and other Elements in High Altitude Aerosols

    Science.gov (United States)

    Mahoney, M.; Murphy, D. M.; Thomson, D. S.

    1998-01-01

    Recent in situ measurements of the chemical composition of single aerosol particles at altitudes up to 19 km have revealed a number of surprising features about ambient particles. Upper tropospheric aerosols in the study region often contained more organic material than sulfate.

  7. Instrument comparison for Aerosolized Titanium Dioxide

    Science.gov (United States)

    Ranpara, Anand

    Recent toxicological studies have shown that the surface area of ultrafine particles (UFP i.e., particles with diameters less than 0.1 micrometer) has a stronger correlation with adverse health effects than does mass of these particles. Ultrafine titanium dioxide (TiO2) particles are widely used in industry, and their use is associated with adverse health outcomes, such as micro vascular dysfunctions and pulmonary damages. The primary aim of this experimental study was to compare a variety of laboratory and industrial hygiene (IH) field study instruments all measuring the same aerosolized TiO2. The study also observed intra-instrument variability between measurements made by two apparently identical devices of the same type of instrument placed side-by-side. The types of instruments studied were (1) DustTrak(TM) DRX, (2) Personal Data RAMs(TM) (PDR), (3) GRIMM, (4) Diffusion charger (DC) and (5) Scanning Mobility Particle Sizer (SMPS). Two devices of each of the four IH field study instrument types were used to measure six levels of mass concentration of fine and ultrafine TiO2 aerosols in controlled chamber tests. Metrics evaluated included real-time mass, active surface area and number/geometric surface area distributions, and off-line gravimetric mass and morphology on filters. DustTrak(TM) DRXs and PDRs were used for mass concentration measurements. DCs were used for active surface area concentration measurements. GRIMMs were used for number concentration measurements. SMPS was used for inter-instrument comparisons of surface area and number concentrations. The results indicated that two apparently identical devices of each DRX and PDR were statistically not different with each other for all the trials of both the sizes of powder (p < 5%). Mean difference between mass concentrations measured by two DustTrak DRX devices was smaller than that measured by two PDR devices. DustTrak DRX measurements were closer to the reference method, gravimetric mass concentration

  8. Comparisons of Airborne HSRL and Modeled Aerosol Profiles

    Science.gov (United States)

    Ferrare, R. A.; Burton, S. P.; Hostetler, C. A.; Hair, J. W.; Ismail, S.; Rogers, R. R.; Notari, A.; Berkoff, T.; Butler, C. F.; Collins, J. E., Jr.; Fenn, M. A.; Scarino, A. J.; Clayton, M.; Mueller, D.; Chemyakin, E.; Fast, J. D.; Berg, L. K.; Randles, C. A.; Colarco, P. R.; daSilva, A.

    2014-12-01

    continental United States. DIAL/HSRL measurements acquired during SEAC4RS allow comparisons with GEOS-5 simulations of forest fire smoke over the western U.S. The fraction of aerosol extinction attributed to dust derived from the DIAL/HSRL depolarization measurements are compared with the corresponding GEOS-5 dust simulations.

  9. MISR Aerosol Product Attributes and Statistical Comparisons with MODIS

    Science.gov (United States)

    Kahn, Ralph A.; Nelson, David L.; Garay, Michael J.; Levy, Robert C.; Bull, Michael A.; Diner, David J.; Martonchik, John V.; Paradise, Susan R.; Hansen, Earl G.; Remer, Lorraine A.

    2009-01-01

    In this paper, Multi-angle Imaging SpectroRadiometer (MISR) aerosol product attributes are described, including geometry and algorithm performance flags. Actual retrieval coverage is mapped and explained in detail using representative global monthly data. Statistical comparisons are made with coincident aerosol optical depth (AOD) and Angstrom exponent (ANG) retrieval results from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The relationship between these results and the ones previously obtained for MISR and MODIS individually, based on comparisons with coincident ground-truth observations, is established. For the data examined, MISR and MODIS each obtain successful aerosol retrievals about 15% of the time, and coincident MISR-MODIS aerosol retrievals are obtained for about 6%-7% of the total overlap region. Cloud avoidance, glint and oblique-Sun exclusions, and other algorithm physical limitations account for these results. For both MISR and MODIS, successful retrievals are obtained for over 75% of locations where attempts are made. Where coincident AOD retrievals are obtained over ocean, the MISR-MODIS correlation coefficient is about 0.9; over land, the correlation coefficient is about 0.7. Differences are traced to specific known algorithm issues or conditions. Over-ocean ANG comparisons yield a correlation of 0.67, showing consistency in distinguishing aerosol air masses dominated by coarse-mode versus fine-mode particles. Sampling considerations imply that care must be taken when assessing monthly global aerosol direct radiative forcing and AOD trends with these products, but they can be used directly for many other applications, such as regional AOD gradient and aerosol air mass type mapping and aerosol transport model validation. Users are urged to take seriously the published product data-quality statements.

  10. Secondary organic material formed by methylglyoxal in aqueous aerosol mimics

    Directory of Open Access Journals (Sweden)

    N. Sareen

    2010-02-01

    Full Text Available We show that methylglyoxal forms light-absorbing secondary organic material in aqueous ammonium sulfate and ammonium nitrate solutions mimicking tropospheric aerosol particles. The kinetics were characterized using UV-Vis spectrophotometry. The results suggest that the bimolecular reaction of methylglyoxal with an ammonium or hydronium ion is the rate-limiting step for the formation of light-absorbing species, with kNH4+II=5×10−6 M−1 min−1 and kH3O+II≤10−3 M−1 min−1. Evidence of aldol condensation products and oligomeric species up to 759 amu was found using chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS. Tentative identifications of carbon-nitrogen species and a sulfur-containing compound were also made using Aerosol-CIMS. Aqueous solutions of methylglyoxal, with and without inorganic salts, exhibit significant surface tension depression. These observations add to the growing body of evidence that dicarbonyl compounds may form secondary organic material in the aerosol aqueous phase, and that secondary organic aerosol formation via heterogeneous processes may affect seed aerosol properties.

  11. Global two-channel AVHRR aerosol climatology: effects of stratospheric aerosols and preliminary comparisons with MODIS and MISR retrievals

    International Nuclear Information System (INIS)

    Geogdzhayev, Igor V.; Mishchenko, Michael I.; Liu Li; Remer, Lorraine

    2004-01-01

    We present an update on the status of the global climatology of the aerosol column optical thickness and Angstrom exponent derived from channel-1 and -2 radiances of the Advanced Very High Resolution Radiometer (AVHRR) in the framework of the Global Aerosol Climatology Project (GACP). The latest version of the climatology covers the period from July 1983 to September 2001 and is based on an adjusted value of the diffuse component of the ocean reflectance as derived from extensive comparisons with ship sun-photometer data. We use the updated GACP climatology and Stratospheric Aerosol and Gas Experiment (SAGE) data to analyze how stratospheric aerosols from major volcanic eruptions can affect the GACP aerosol product. One possible retrieval strategy based on the AVHRR channel-1 and -2 data alone is to infer both the stratospheric and the tropospheric aerosol optical thickness while assuming fixed microphysical models for both aerosol components. The second approach is to use the SAGE stratospheric aerosol data in order to constrain the AVHRR retrieval algorithm. We demonstrate that the second approach yields a consistent long-term record of the tropospheric aerosol optical thickness and Angstrom exponent. Preliminary comparisons of the GACP aerosol product with MODerate resolution Imaging Spectrometer (MODIS) and Multiangle Imaging Spectro-Radiometer aerosol retrievals show reasonable agreement, the GACP global monthly optical thickness being lower than the MODIS one by approximately 0.03. Larger differences are observed on a regional scale. Comparisons of the GACP and MODIS Angstrom exponent records are less conclusive and require further analysis

  12. Sodium oxide aerosol behavior in a closed vessel. Comparison of computer modeling with aerosol experiments

    International Nuclear Information System (INIS)

    Fermandjian, Jean.

    1979-08-01

    Fast breeder reactor safety needs models validated to predict the behavior of sodium aerosols in the different reactor compartments during hypothetical sodium accident. Besides their chemical toxicity, the sodium aerosols are a transfer vector of radioactivity during a contaminated sodium fire. The purpose of this work is to validate models (HAARM 2 and PARDISEKO 3) with tests of sodium pool fires in a 400 m 3 concrete vessel in a confined atmosphere (CASSANDRE tests). The comparison between calculations and experimental results reveals that difficulties still exist, especially as to the selection of the values to be given to some input parameters (physical data of experimental origin, in particular the aerosols source function, the characteristics of the distribution of the emitted particles and the form factor of the agglomerated particles) [fr

  13. Nanocrystalline functional materials and nanocomposites synthesis through aerosol routes

    Directory of Open Access Journals (Sweden)

    Milošević Olivera B.

    2003-01-01

    Full Text Available This paper represents the results of the design of functional nanocrystalline powders and nanocomposites using chemical reactions in aerosols. The process involves ultrasonic aerosol formation (mist generators with the resonant frequencies of 800 kHz, 1.7 and 2.5 MHz from precursor salt solutions and control over the aerosol decomposition in a high-temperature tubular flow reactor. During decomposition, the aerosol droplets undergo evaporation/drying, precipitation and thermolysis in a single-step process. Consequently, spherical, solid, agglomerate-free submicronic particles are obtained. The particle morphology, revealed as a composite structure consisting of primary crystallites smaller than 20 nm was analysed by several methods (XRD, DSC/DTA, SEM, TEM and discussed in terms of precursor chemistry and process parameters. Following the initial attempts, a more detailed aspect of nanocrystalline particle synthesis was demonstrated for the case of nanocomposites based on ZnO-MeO (MeO=Bi Cr+, suitable for electronic applications, as well as an yttrium-aluminum base complex system, suitable for phosphorus applications. The results imply that parts of the material structure responsible for different functional behaviour appear through in situ aerosol synthesis by processes of intraparticle agglomeration, reaction and sintering in the last synthesis stage.

  14. Summary of aerosol code-comparison results for LWR aerosol containment tests LA1, LA2, and LA3

    International Nuclear Information System (INIS)

    Wright, A.L.; Wilson, J.H.; Arwood, P.C.

    1987-01-01

    The light-water reactor (LWR) aerosol containment experiments (LACE) are being performed in Richland, Washington, at the Hanford Engineering Development Laboratory under the leadership of an international project board and the Electric Power Research Institute. These tests have two objectives: (1) to investigate, at large scale, the inherent aerosol retention behavior in LWR containments under simulated severe accident conditions, and (2) to provide an experimental data base for validating aerosol behavior and thermal-hydraulic computer codes. Aerosol computer-code comparison activities for the LACE tests are being coordinated at the Oak Ridge National Laboratory. For each of the six experiments, pretest calculations (for code-to-code comparisons) and blind post-test calculations (for code-to-test data comparisons) are being performed. This paper presents a summary of the pretest aerosol-code results for tests LA1, LA2, and LA3

  15. Nuclear aerosol behaviour in LMFBR. Comparison of computer modelling with aerosol experiments

    Energy Technology Data Exchange (ETDEWEB)

    Fermandjian, J [DSN/Centre de Fontenay-aux-Roses, Fontenay-aux-Roses (France)

    1979-03-01

    For the purpose of studying the behaviour of the concentration of aerosols confined in a vessel, various models have been developed, especially in the United States: HAA 3B, HAARM 2 and HAARM 3 - in the Federal Republic of Germany: PARDISEKO 3 and PARDISEKO 3 B - in Japan: ABC 2 and ABC 3 - in the United Kingdom: AEROSIM and in the Netherlands: ETHERDEMO and MADCA. These codes were validated on the basis of tests conducted in vessels whose volumes varied between 0.022 and 850 m{sup 3}. The aerosols studied differed in nature (sodium oxide, fuel oxide, sodium oxide-fuel oxide, gold) and method of production (sodium pool fires, sodium spray fires, arc vaporization, exploding wire) in various atmospheres air, air with variable amounts of oxygen, and nitrogen. This comparison between calculation and experimental results reveals that difficulties still exist, especially as to the selection of the values to be given to some input parameters of the codes (physical data of experimental origin, in particular, the aerosol source function and the characteristics of the size distribution of the emitted particles). Furthermore, the importance of thermophoresis and convection currents has been proved: including the soaring effect in the ABC 3 code enables to fit the experiment. (author)

  16. Nuclear aerosol behaviour in LMFBR. Comparison of computer modelling with aerosol experiments

    International Nuclear Information System (INIS)

    Fermandjian, J.

    1979-01-01

    For the purpose of studying the behaviour of the concentration of aerosols confined in a vessel, various models have been developed, especially in the United States: HAA 3B, HAARM 2 and HAARM 3 - in the Federal Republic of Germany: PARDISEKO 3 and PARDISEKO 3 B - in Japan: ABC 2 and ABC 3 - in the United Kingdom: AEROSIM and in the Netherlands: ETHERDEMO and MADCA. These codes were validated on the basis of tests conducted in vessels whose volumes varied between 0.022 and 850 m 3 . The aerosols studied differed in nature (sodium oxide, fuel oxide, sodium oxide-fuel oxide, gold) and method of production (sodium pool fires, sodium spray fires, arc vaporization, exploding wire) in various atmospheres air, air with variable amounts of oxygen, and nitrogen. This comparison between calculation and experimental results reveals that difficulties still exist, especially as to the selection of the values to be given to some input parameters of the codes (physical data of experimental origin, in particular, the aerosol source function and the characteristics of the size distribution of the emitted particles). Furthermore, the importance of thermophoresis and convection currents has been proved: including the soaring effect in the ABC 3 code enables to fit the experiment. (author)

  17. Real-time aerosol photometer and optical particle counter comparison

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  18. Synthesis and Surface-Specific Analysis of Molecular Constituents Relevant to Biogenic Secondary Organic Aerosol Material

    Science.gov (United States)

    Be, A. G.; Upshur, M. A.; Chase, H. M.; Geiger, F.; Thomson, R. J.

    2017-12-01

    Secondary organic aerosol (SOA) particles formed from the oxidation of biogenic volatile organic compounds (BVOCs) remain a principal, yet elusive, class of airborne particulate matter that impacts the Earth's radiation budget. Given the characteristic molecular complexity comprising biogenic SOA particles, chemical information selective to the gas-aerosol interface may be valuable in the investigation of such systems, as surface considerations likely dictate the phenomena driving particle evolution mechanisms and climate effects. In particular, cloud activation processes may be parameterized using the surface tension depression that coincides with partitioning of surface-active organic species to the gas-droplet interface. However, the extent to which surface chemical processes, such as cloud droplet condensation, are influenced by the chemical structure and reactivity of individual surface-active molecules in SOA particles is largely unknown. We seek to study terpene-derived organic species relevant to the surfaces of biogenic SOA particles via synthesis of putative oxidation products followed by analysis using surface-selective physicochemical measurements. Using dynamic surface tension measurements, considerable differences are observed in the surface tension depression of aqueous pendant droplets that contain synthetically prepared ozonolysis products derived from abundant terpene precursors. Furthermore, sum frequency generation spectroscopy is utilized for comparison of the surface vibrational spectral responses of synthesized reference compounds with those observed for laboratory aerosol toward probing the surface composition of SOA material. Such ongoing findings highlight the underlying importance of molecular structure and reactivity when considering the surface chemistry of biogenic terpene-derived atmospheric aerosols.

  19. Tribological comparison of materials

    Science.gov (United States)

    Shi, Bing

    Approximately 600,000 total joint replacement surgeries are performed each year in the United States. Current artificial joint implants are mainly metal-on-plastic. The synthetic biomaterials undergo degradation through fatigue and corrosive wear from load-bearing and the aqueous ionic environment of the human body. Deposits of inorganic salts can scratch weight-bearing surfaces, making artificial joints stiff and awkward. The excessive wear debris from polyethylene leads to osteolysis and potential loosening of the prosthesis. The lifetime for well-designed artificial joints is at most 10 to 15 years. A patient can usually have two total joint replacements during her/his lifetime. Durability is limited by the body's reaction to wear debris of the artificial joints. Wear of the artificial joints should be reduced. A focus of this thesis is the tribological performance of bearing materials for Total Replacement Artificial Joints (TRAJ). An additional focus is the scaffolds for cell growth from both a tissue engineering and tribological perspective. The tribological properties of materials including Diamond-like Carbon (DLC) coated materials were tested for TRAJ implants. The DLC coatings are chemically inert, impervious to acid and saline media, and are mechanically hard. Carbon-based materials are highly biocompatible. A new alternative to total joints implantation is tissue engineering. Tissue engineering is the replacement of living tissue with tissue that is designed and constructed to meet the needs of the individual patient. Cells were cultured onto the artificial materials, including metals, ceramics, and polymers, and the frictional properties of these materials were investigated to develop a synthetic alternative to orthopedic transplants. Results showed that DLC coated materials had low friction and wear, which are desirable tribological properties for artificial joint material. Cells grew on some of the artificial matrix materials, depending on the

  20. Neutralization of Aerosolized Bio-Agents by Filled Nanocomposite Materials through Thermal and Chemical Inactivation Mechanisms

    Science.gov (United States)

    2016-06-01

    Bio -agents by Filled Nanocomposite Materials through Thermal and Chemical Inactivation Mechanisms Distribution Statement A. Approved for public...of Cincinnati Project Title: Neutralization of Aerosolized Bio -agents by Filled Nanocomposite Materials through Thermal and Chemical Inactivation...fire ball, where they will not effectively interact with any viable bio -aerosol. 1.1.4. Conclusions Cryo-milling is necessary to achieve a

  1. Comparison of computer codes related to the sodium oxide aerosol behavior in a containment building

    International Nuclear Information System (INIS)

    Fermandjian, J.

    1984-09-01

    In order to ensure that the problems of describing the physical behavior of sodium aerosols, during hypothetical fast reactor accidents, were adequately understood, a comparison of the computer codes (ABC/INTG, PNC, Japan; AEROSIM, UKAEA/SRD, United Kingdom; PARDISEKO IIIb, KfK, Germany; AEROSOLS/A2 and AEROSOLS/B1, CEA France) was undertaken in the frame of the CEC: exercise in which code users have run their own codes with a prearranged input

  2. The influence of bedding materials on bio-aerosol exposure in dairy barns exposure in dairy barns

    NARCIS (Netherlands)

    Samadi, S.; van Eerdenburg, F.J.C.M.; Jamshidifard, A.R.; Otten, G.P.; Droppert, M.; Heederik, D.J.J.; Wouters, I.M.

    2012-01-01

    Bio-aerosol is a well-known cause of respiratory diseases. Exposure to bio-aerosols has been reported previously in dairy barns, but little is known about the sources of bio-aerosol. Bedding materials might be a significant source or substrate for bio-aerosol exposure. The aim of this study was to

  3. Comparison of aerosol extinction between lidar and SAGE II over Gadanki, a tropical station in India

    Directory of Open Access Journals (Sweden)

    P. Kulkarni

    2015-03-01

    Full Text Available An extensive comparison of aerosol extinction has been performed using lidar and Stratospheric Aerosol and Gas Experiment (SAGE II data over Gadanki (13.5° N, 79.2° E, a tropical station in India, following coincident criteria during volcanically quiescent conditions from 1998 to 2005. The aerosol extinctions derived from lidar are higher than SAGE II during all seasons in the upper troposphere (UT, while in the lower-stratosphere (LS values are closer. The seasonal mean percent differences between lidar and SAGE II aerosol extinctions are > 100% in the UT and Ba (sr−1, the ratio between aerosol backscattering and extinction, are needed for the tropics for a more accurate derivation of aerosol extinction.

  4. Maritime Aerosol Network as a Component of AERONET - First Results and Comparison with Global Aerosol Models and Satellite Retrievals

    Science.gov (United States)

    Smirnov, A.; Holben, B. N.; Giles, D. M.; Slutsker, I.; O'Neill, N. T.; Eck, T. F.; Macke, A.; Croot, P.; Courcoux, Y.; Sakerin, S. M.; hide

    2011-01-01

    The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. Over 80 cruises were completed through early 2010 with deployments continuing. Measurement areas included various parts of the Atlantic Ocean, the Northern and Southern Pacific Ocean, the South Indian Ocean, the Southern Ocean, the Arctic Ocean and inland seas. MAN deploys Microtops handheld sunphotometers and utilizes a calibration procedure and data processing traceable to AERONET. Data collection included areas that previously had no aerosol optical depth (AOD) coverage at all, particularly vast areas of the Southern Ocean. The MAN data archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we present results of AOD measurements over the oceans, and make a comparison with satellite AOD retrievals and model simulations.

  5. Maritime aerosol network as a component of AERONET – first results and comparison with global aerosol models and satellite retrievals

    Directory of Open Access Journals (Sweden)

    A. Smirnov

    2011-03-01

    Full Text Available The Maritime Aerosol Network (MAN has been collecting data over the oceans since November 2006. Over 80 cruises were completed through early 2010 with deployments continuing. Measurement areas included various parts of the Atlantic Ocean, the Northern and Southern Pacific Ocean, the South Indian Ocean, the Southern Ocean, the Arctic Ocean and inland seas. MAN deploys Microtops hand-held sunphotometers and utilizes a calibration procedure and data processing traceable to AERONET. Data collection included areas that previously had no aerosol optical depth (AOD coverage at all, particularly vast areas of the Southern Ocean. The MAN data archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we present results of AOD measurements over the oceans, and make a comparison with satellite AOD retrievals and model simulations.

  6. Comparison of Aerosol Delivery by Face Mask and Tracheostomy Collar.

    Science.gov (United States)

    Bugis, Alaa A; Sheard, Meryl M; Fink, James B; Harwood, Robert J; Ari, Arzu

    2015-09-01

    The purpose of this study was to compare the performance of a tracheostomy collar, Wright mask, and aerosol mask attached to a jet nebulizer in facilitating aerosolized medication delivery to the lungs. We also compared albuterol delivery with open versus closed fenestration and determined the effect of inspiratory-expiratory ratio (I:E) on aerosol delivery. Albuterol (2.5 mg/3 mL) was administered to an in vitro model consisting of an adult teaching mannequin extrathoracic and upper airway with stoma intubated with an 8-mm fenestrated tracheostomy tube. The cuff was deflated. A collecting filter at the level of the bronchi was connected to a breathing simulator at a tidal volume of 400 mL, breathing frequency of 20 breaths/min, and I:E of 2:1 and 1:2. A jet nebulizer was operated with O2 at 8 L/min. Each interface was tested in triplicate. The flow was discontinued at the end of nebulization. For each test, the nebulizer was attached to a tracheostomy collar with the fenestration open or closed, a Wright mask, or an aerosol mask. Drug was analyzed by spectrophotometry (276 nm). A paired t test and analysis of variance were performed (P mask (4.1 ± 0.6%) and aerosol mask (3.5 ± 0.04%) were both less than with the tracheostomy collar under either condition (P mask (7.2 ± 0.6%), and aerosol mask (6.1 ± 0.5%). In an adult tracheostomy model, the tracheostomy collar delivered more aerosol to the bronchi than the Wright or aerosol mask. An I:E of 2:1 caused greater aerosol deposition compared with an I:E of 1:2. During aerosol administration via a tracheostomy collar, closing the fenestration improved aerosol delivery. Copyright © 2015 by Daedalus Enterprises.

  7. Quantifying the risks of solid aerosol geoengineering: the role of fundamental material properties

    Science.gov (United States)

    Dykema, J. A.; Keutsch, F. N.; Keith, D.

    2017-12-01

    Solid aerosols have been considered as an alternative to sulfate aerosols for solar geoengineering due to their optical and chemical properties, which lead to different and possibly more attractive risk profiles. Solid aerosols can achieve higher solar scattering efficiency due to their higher refractive index, and in some cases may also be less effective absorbers of thermal infrared radiation. The optical properties of solid aerosols are however sensitive functions of the detailed physical properties of solid materials in question. The relevant details include the exact crystalline structure of the aerosols, the physical size of the particles, and interactions with background stratospheric molecular and particulate constituents. In this work, we examine the impact of these detailed physical properties on the radiative properties of calcite (CaCO3) solid aerosols. We examine how crystal morphology, size, chemical reactions, and interaction with background stratospheric aerosol may alter the scattering and absorption properties of calcite aerosols for solar and thermal infrared radiation. For example, in small particles, crystal lattice vibrations associated with the particle surface may lead to substantially different infrared absorption properties than bulk materials. We examine the wavelength dependence of absorption by the particles, which may lead to altered patterns of stratospheric radiative heating and equilibrium temperatures. Such temperature changes can lead to dynamical changes, with consequences for both stratospheric composition and tropospheric climate. We identify important uncertainties in the current state of understanding, investigate risks associated with these uncertainties, and survey potential approaches to quantitatively improving our knowledge of the relevant material properties.

  8. Aerosol comparisons between sunphotometry / sky radiometry and the GEOS-Chem model

    Science.gov (United States)

    Chaubey, J. P.; Hesaraki, S.; O'Neill, N. T.; Saha, A.; Martin, R.; Lesins, G. B.; Abboud, I.

    2014-12-01

    Comparisons of aerosol optical depth (AOD), spectral AOD parameters and microphysical parameters derived from AEROCAN / AERONET sunphotometer / sky radiometer data acquired over Canada were compared with GEOS-Chem (Geos5,v9-01-03) estimations. The Canadian sites were selected so as to encompass a representative variety of different aerosol types ranging from fine mode (submicron) pollution and smoke aerosols, coarse mode (supermicron) dust, fine and coarse mode marine aerosols, volcanic (fine mode) sulfates and volcanic (coarse mode) ash, etc). A particular focus was placed on comparisons at remote Canadian sites with a further focus on Arctic sites. The analysis included meteorological-scale event comparisons as well as seasonal and yearly comparisons on a climatological scale. The investigations were given a further aerosol type context by comparing optical retrievals of fine and coarse mode AOD with the AODs of the different aerosol types predicted by GEOS-Chem. The effects of temporal and spectral cloud screening of the sunphotometer data on the quality and robustness of these comparisons was the object of an important supporting investigation. The results of this study will be presented for a 3 year period from 2009 to 2011.

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

    Science.gov (United States)

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

    2011-08-01

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

  10. Comparison of aerosol behavior codes with experimental results from a sodium fire in a containment

    International Nuclear Information System (INIS)

    Lhiaubet, G.; Kissane, M.P.; Seino, H.; Miyake, O.; Himeno, Y.

    1990-01-01

    The containment expert group (CONT), a subgroup of the CEC fast reactor Safety Working Group (SWG), has carried out several studies on the behavior of sodium aerosols which might form in a severe fast reactor accident during which primary sodium leaks into the secondary containment. These studies comprise an intercalibration of measurement devices used to determine the aerosol particle size spectrum, and the analysis and comparison of codes applied to the determination of aerosol behavior in a reactor containment. The paper outlines the results of measurements of typical data made for aerosols produced in a sodium fire and their comparison with results from different codes (PARDISEKO, AEROSIM, CONTAIN, AEROSOLS/B2). The sodium fire experiment took place at CEN-Cadarache (France) in a 400 m 3 vessel. The fire lasted 90 minutes and the aerosol measurements were made over 10 hours at different locations inside the vessel. The results showed that the suspended mass calculated along the time with different codes was in good agreement with the experiment. However, the calculated aerosol deposition on the walls was diverging and always significantly lower than the measured values

  11. Spatial Interpolation of Aerosol Optical Depth Pollution: Comparison of Methods for the Development of Aerosol Distribution

    Science.gov (United States)

    Safarpour, S.; Abdullah, K.; Lim, H. S.; Dadras, M.

    2017-09-01

    Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters are important due to health impact. One widely available metric of aerosol abundance is the aerosol optical depth (AOD). The AOD is the integrated light extinction coefficient over a vertical atmospheric column of unit cross section, which represents the extent to which the aerosols in that vertical profile prevent the transmission of light by absorption or scattering. Seasonal aerosol optical depth (AOD) values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Terra satellites, for the 10 years period of 2000 - 2010 were used to test 7 different spatial interpolation methods in the present study. The accuracy of estimations was assessed through visual analysis as well as independent validation based on basic statistics, such as root mean square error (RMSE) and correlation coefficient. Based on the RMSE and R values of predictions made using measured values from 2000 to 2010, Radial Basis Functions (RBFs) yielded the best results for spring, summer and winter and ordinary kriging yielded the best results for fall.

  12. SPATIAL INTERPOLATION OF AEROSOL OPTICAL DEPTH POLLUTION: COMPARISON OF METHODS FOR THE DEVELOPMENT OF AEROSOL DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    S. Safarpour

    2017-09-01

    Full Text Available Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters are important due to health impact. One widely available metric of aerosol abundance is the aerosol optical depth (AOD. The AOD is the integrated light extinction coefficient over a vertical atmospheric column of unit cross section, which represents the extent to which the aerosols in that vertical profile prevent the transmission of light by absorption or scattering. Seasonal aerosol optical depth (AOD values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS sensor onboard NASA’s Terra satellites, for the 10 years period of 2000 - 2010 were used to test 7 different spatial interpolation methods in the present study. The accuracy of estimations was assessed through visual analysis as well as independent validation based on basic statistics, such as root mean square error (RMSE and correlation coefficient. Based on the RMSE and R values of predictions made using measured values from 2000 to 2010, Radial Basis Functions (RBFs yielded the best results for spring, summer and winter and ordinary kriging yielded the best results for fall.

  13. Results and code prediction comparisons of lithium-air reaction and aerosol behavior tests

    International Nuclear Information System (INIS)

    Jeppson, D.W.

    1986-03-01

    The Hanford Engineering Development Laboratory (HEDL) Fusion Safety Support Studies include evaluation of potential safety and environmental concerns associated with the use of liquid lithium as a breeder and coolant for fusion reactors. Potential mechanisms for volatilization and transport of radioactive metallic species associated with breeder materials are of particular interest. Liquid lithium pool-air reaction and aerosol behavior tests were conducted with lithium masses up to 100 kg within the 850-m 3 containment vessel in the Containment Systems Test Facility. Lithium-air reaction rates, aerosol generation rates, aerosol behavior and characterization, as well as containment atmosphere temperature and pressure responses were determined. Pool-air reaction and aerosol behavior test results were compared with computer code calculations for reaction rates, containment atmosphere response, and aerosol behavior. The volatility of potentially radioactive metallic species from a lithium pool-air reaction was measured. The response of various aerosol detectors to the aerosol generated was determined. Liquid lithium spray tests in air and in nitrogen atmospheres were conducted with lithium temperatures of about 427 0 and 650 0 C. Lithium reaction rates, containment atmosphere response, and aerosol generation and characterization were determined for these spray tests

  14. An overview of mesoscale aerosol processes, comparisons, and validation studies from DRAGON networks

    Science.gov (United States)

    Holben, Brent N.; Kim, Jhoon; Sano, Itaru; Mukai, Sonoyo; Eck, Thomas F.; Giles, David M.; Schafer, Joel S.; Sinyuk, Aliaksandr; Slutsker, Ilya; Smirnov, Alexander; Sorokin, Mikhail; Anderson, Bruce E.; Che, Huizheng; Choi, Myungje; Crawford, James H.; Ferrare, Richard A.; Garay, Michael J.; Jeong, Ukkyo; Kim, Mijin; Kim, Woogyung; Knox, Nichola; Li, Zhengqiang; Lim, Hwee S.; Liu, Yang; Maring, Hal; Nakata, Makiko; Pickering, Kenneth E.; Piketh, Stuart; Redemann, Jens; Reid, Jeffrey S.; Salinas, Santo; Seo, Sora; Tan, Fuyi; Tripathi, Sachchida N.; Toon, Owen B.; Xiao, Qingyang

    2018-01-01

    Over the past 24 years, the AErosol RObotic NETwork (AERONET) program has provided highly accurate remote-sensing characterization of aerosol optical and physical properties for an increasingly extensive geographic distribution including all continents and many oceanic island and coastal sites. The measurements and retrievals from the AERONET global network have addressed satellite and model validation needs very well, but there have been challenges in making comparisons to similar parameters from in situ surface and airborne measurements. Additionally, with improved spatial and temporal satellite remote sensing of aerosols, there is a need for higher spatial-resolution ground-based remote-sensing networks. An effort to address these needs resulted in a number of field campaign networks called Distributed Regional Aerosol Gridded Observation Networks (DRAGONs) that were designed to provide a database for in situ and remote-sensing comparison and analysis of local to mesoscale variability in aerosol properties. This paper describes the DRAGON deployments that will continue to contribute to the growing body of research related to meso- and microscale aerosol features and processes. The research presented in this special issue illustrates the diversity of topics that has resulted from the application of data from these networks.

  15. An overview of mesoscale aerosol processes, comparisons, and validation studies from DRAGON networks

    Directory of Open Access Journals (Sweden)

    B. N. Holben

    2018-01-01

    Full Text Available Over the past 24 years, the AErosol RObotic NETwork (AERONET program has provided highly accurate remote-sensing characterization of aerosol optical and physical properties for an increasingly extensive geographic distribution including all continents and many oceanic island and coastal sites. The measurements and retrievals from the AERONET global network have addressed satellite and model validation needs very well, but there have been challenges in making comparisons to similar parameters from in situ surface and airborne measurements. Additionally, with improved spatial and temporal satellite remote sensing of aerosols, there is a need for higher spatial-resolution ground-based remote-sensing networks. An effort to address these needs resulted in a number of field campaign networks called Distributed Regional Aerosol Gridded Observation Networks (DRAGONs that were designed to provide a database for in situ and remote-sensing comparison and analysis of local to mesoscale variability in aerosol properties. This paper describes the DRAGON deployments that will continue to contribute to the growing body of research related to meso- and microscale aerosol features and processes. The research presented in this special issue illustrates the diversity of topics that has resulted from the application of data from these networks.

  16. Adsorption and revaporisation studies on iodine oxide aerosols deposited on containment surface materials in LWR

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.R.StJ.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Lamminmaeki, S.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2012-12-15

    During a hypothetical severe nuclear accident, the radiation field will be very high in the nuclear reactor containment building. As a result gaseous radiolysis products will be formed. Elemental iodine can react in the gaseous phase with ozone to form solid iodine oxide aerosol particles (iodine oxide). Within the AIAS (Adsorption of Iodine oxide Aerosols on Surfaces) project the interactions of iodine oxide (IOx) aerosols with common containment surface materials were investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS, as well as Pt and Pd surfaces from hydrogen recombiners. Non-radioactive and {sup 131}I labelled iodine oxide aerosols were produced with the EXSI CONT facility from elemental iodine and ozone at VTT Technical Research Centre of Finland. The iodine oxide deposits were analysed with microscopic and spectroscopic measurement techniques to identify the kind of iodine oxide formed and if a chemical conversion on the different surface materials occurs. The revaporisation behaviour of the deposited iodine oxide aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 having a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The revaporisated {sup 131}I species from the surfaces were chemically tested for elemental iodine formation. The parameter dominating the degradation of the produced iodine oxide aerosols was humidity. Cu and Zn surfaces were found to react with iodine from the iodine oxide aerosols to form iodides, while no metal iodides were detected for Al and SS samples. Most of the iodine oxide aerosols are assumed to

  17. Adsorption and revaporisation studies on iodine oxide aerosols deposited on containment surface materials in LWR

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.R.StJ.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Lamminmaeki, S.; Jokiniemi, J.

    2012-12-01

    During a hypothetical severe nuclear accident, the radiation field will be very high in the nuclear reactor containment building. As a result gaseous radiolysis products will be formed. Elemental iodine can react in the gaseous phase with ozone to form solid iodine oxide aerosol particles (iodine oxide). Within the AIAS (Adsorption of Iodine oxide Aerosols on Surfaces) project the interactions of iodine oxide (IOx) aerosols with common containment surface materials were investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS, as well as Pt and Pd surfaces from hydrogen recombiners. Non-radioactive and 131 I labelled iodine oxide aerosols were produced with the EXSI CONT facility from elemental iodine and ozone at VTT Technical Research Centre of Finland. The iodine oxide deposits were analysed with microscopic and spectroscopic measurement techniques to identify the kind of iodine oxide formed and if a chemical conversion on the different surface materials occurs. The revaporisation behaviour of the deposited iodine oxide aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 having a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The revaporisated 131 I species from the surfaces were chemically tested for elemental iodine formation. The parameter dominating the degradation of the produced iodine oxide aerosols was humidity. Cu and Zn surfaces were found to react with iodine from the iodine oxide aerosols to form iodides, while no metal iodides were detected for Al and SS samples. Most of the iodine oxide aerosols are assumed to be

  18. Secondary organic aerosol: a comparison between foggy and nonfoggy days.

    Science.gov (United States)

    Kaul, D S; Gupta, Tarun; Tripathi, S N; Tare, V; Collett, J L

    2011-09-01

    Carbonaceous species, meteorological parameters, trace gases, and fogwater chemistry were measured during winter in the Indian city of Kanpur to study secondary organic aerosol (SOA) during foggy and clear (nonfoggy) days. Enhanced SOA production was observed during fog episodes. It is hypothesized that aqueous phase chemistry in fog drops is responsible for increasing SOA production. SOA concentrations on foggy days exceeded those on clear days at all times of day; peak foggy day SOA concentrations were observed in the evening vs peak clear day SOA concentrations which occurred in the afternoon. Changes in biomass burning emissions on foggy days were examined because of their potential to confound estimates of SOA production based on analysis of organic to elemental carbon (OC/EC) ratios. No evidence of biomass burning influence on SOA during foggy days was found. Enhanced oxidation of SO(2) to sulfate during foggy days was observed, possibly causing the regional aerosol to become more acidic. No evidence was found in this study, either, for effects of temperature or relative humidity on SOA production. In addition to SOA production, fogs can also play an important role in cleaning the atmosphere of carbonaceous aerosols. Preferential scavenging of water-soluble organic carbon (WSOC) by fog droplets was observed. OC was found to be enriched in smaller droplets, limiting the rate of OC deposition by droplet sedimentation. Lower EC concentrations were observed on foggy days, despite greater stagnation and lower mixing heights, suggesting fog scavenging and removal of EC was active as well.

  19. Comparisons of spectral aerosol single scattering albedo in Seoul, South Korea

    Science.gov (United States)

    Mok, Jungbin; Krotkov, Nickolay A.; Torres, Omar; Jethva, Hiren; Li, Zhanqing; Kim, Jhoon; Koo, Ja-Ho; Go, Sujung; Irie, Hitoshi; Labow, Gordon; Eck, Thomas F.; Holben, Brent N.; Herman, Jay; Loughman, Robert P.; Spinei, Elena; Lee, Seoung Soo; Khatri, Pradeep; Campanelli, Monica

    2018-04-01

    Quantifying aerosol absorption at ultraviolet (UV) wavelengths is important for monitoring air pollution and aerosol amounts using current (e.g., Aura/OMI) and future (e.g., TROPOMI, TEMPO, GEMS, and Sentinel-4) satellite measurements. Measurements of column average atmospheric aerosol single scattering albedo (SSA) are performed on the ground by the NASA AERONET in the visible (VIS) and near-infrared (NIR) wavelengths and in the UV-VIS-NIR by the SKYNET networks. Previous comparison studies have focused on VIS and NIR wavelengths due to the lack of co-incident measurements of aerosol and gaseous absorption properties in the UV. This study compares the SKYNET-retrieved SSA in the UV with the SSA derived from a combination of AERONET, MFRSR, and Pandora (AMP) retrievals in Seoul, South Korea, in spring and summer 2016. The results show that the spectrally invariant surface albedo assumed in the SKYNET SSA retrievals leads to underestimated SSA compared to AMP values at near UV wavelengths. Re-processed SKYNET inversions using spectrally varying surface albedo, consistent with the AERONET retrieval improve agreement with AMP SSA. The combined AMP inversions allow for separating aerosol and gaseous (NO2 and O3) absorption and provide aerosol retrievals from the shortest UVB (305 nm) through VIS to NIR wavelengths (870 nm).

  20. Vertical profiles of aerosol optical properties over central Illinois and comparison with surface and satellite measurements

    Directory of Open Access Journals (Sweden)

    P. J. Sheridan

    2012-12-01

    lidar. In this study, aerosol layers with light extinction (532 nm values > 50 Mm−1 were detected by CALIPSO ~ 95% of the time, while aerosol layers with extinction values lower than 10 Mm−1 had a detection efficiency of < 2%. For all collocated comparison cases, a 50% probability of detection falls at an in situ extinction level of 20–25 Mm−1. These statistical data offer guidance as to the likelihood of CALIPSO's ability to retrieve aerosol extinction at various locations around the globe.

  1. Results of aerosol code comparisons with releases from ACE MCCI tests

    International Nuclear Information System (INIS)

    Fink, J.K.; Corradini, M.; Hidaka, A.; Hontanon, E.; Mignanelli, M.A.; Schroedl, E.; Strizhov, V.

    1992-01-01

    Results of aerosol release calculations by six groups from six countries are compared with the releases from ACE MCCI Test L6. The codes used for these calculations included: SOLGASMIX-PV, SOLGASMIX Reactor 1986, CORCON.UW, VANESA 1.01, and CORCON mod2.04/VANESA 1.01. Calculations were performed with the standard VANESA 1.01 code and with modifications to the VANESA code such as the inclusion of various zirconium-silica chemical reactions. Comparisons of results from these calculations were made with Test L6 release fractions for U, Zr, Si, the fission-product elements Te, Ba, Sr, Ce, La, Mo and control materials Ag, In, and Ru. Reasonable agreement was obtained between calculations and Test L6 results for the volatile elements Ag, In and Te. Calculated releases of the low volatility fission products ranged from within an order of magnitude to five orders of magnitude of Test L6 values. Releases were over and underestimated by calculations. Poorest agreements were obtained for Mo and Si

  2. Numerical Simulation of the Motion of Aerosol Particles in Open Cell Foam Materials

    Science.gov (United States)

    Solovev, S. A.; Soloveva, O. V.; Popkova, O. S.

    2018-03-01

    The motion of aerosol particles in open cell foam material is studied. The porous medium is investigated for a three-dimensional case with detailed simulation of cellular structures within an ordered geometry. Numerical calculations of the motion of particles and their deposition due to inertial and gravitational mechanisms are performed. Deposition efficiency curves for a broad range of particle sizes are constructed. The effect deposition mechanisms have on the efficiency of the porous material as a filter is analyzed.

  3. Sea spray aerosol fluxes in the Baltic Sea region: Comparison of the WAM model with measurements

    Science.gov (United States)

    Markuszewski, Piotr; Kosecki, Szymon; Petelski, Tomasz

    2017-08-01

    Sea spray aerosol flux is an important element of sub-regional climate modeling. The majority of works related to this topic concentrate on open ocean research rather than on smaller, inland seas, e.g., the Baltic Sea. The Baltic Sea is one of the largest brackish inland seas by area, where major inflows of oceanic waters are rare. Furthermore, surface waves in the Baltic Sea have a relatively shorter lifespan in comparison with oceanic waves. Therefore, emission of sea spray aerosol may differ greatly from what is known from oceanic research and should be investigated. This article presents a comparison of sea spray aerosol measurements carried out on-board the s/y Oceania research ship with data calculated in accordance to the WAM model. The measurements were conducted in the southern region of the Baltic Sea during four scientific cruises. The gradient method was used to determinate aerosol fluxes. The fluxes were calculated for particles of diameter in range of 0.5-47 μm. The correlation between wind speed measured and simulated has a good agreement (correlation in range of 0.8). The comparison encompasses three different sea spray generation models. First, function proposed by Massel (2006) which is based only on wave parameters, such as significant wave height and peak frequency. Second, Callaghan (2013) which is based on Gong (2003) model (wind speed relation), and a thorough experimental analysis of whitecaps. Third, Petelski et al. (2014) which is based on in-situ gradient measurements with the function dependent on wind speed. The two first models which based on whitecaps analysis are insufficient. Moreover, the research shows strong relation between aerosol emission and wind speed history.

  4. Clinical assessment of a commercial aerosol delivery system for ventilation scanning by comparison with KR-81m

    International Nuclear Information System (INIS)

    Wollmer, P.; Eriksson, L.; Andersson, A.C.

    1984-01-01

    Radioactive aerosols offer a means for steady state ventilation scanning in multiple views. The clinical use of radioaerosol techniques has been hampered by the lack of delivery systems producing sufficiently small particles. If the aerosol contains large particles, heavy deposition occurs in major airways, especially in patients with airways disease. The authors have assessed a new, commercial aerosol delivery system (Syntevent) by comparison with Kr-81m ventilation scanning in 23 patients with airways obstruction. An indirect comparison was also made with a settling bad technique. Ventilation scans in four projections were obtained during continuous inhalation of Kr-81m. Subsequently, the patient inhaled an aerosol labelled with In-113m from the Syntevent system, and aerosol ventilation scans were obtained in the same projections. Spirometry was performed to establish the degree of airways obstruction. The aerosol delineated the ventilated regions of the lungs adequately in all the patients. Deposition of aerosol in larger airways was seen in a few patients only, and this did not impede the interpretation of the scintigram. A quantitative analysis of the penetration of the aerosol to the periphery of the lung failed to demonstrate any significant correlation between particle penetration and airways obstruction. Aerosol penetration was significantly greater (p<0.001) with the Syntevent system than with a settling bag technique

  5. Clinical assessment of a commercial delivery system for aerosol ventilation scanning by comparison with Krypton-81m

    International Nuclear Information System (INIS)

    Wollmer, P.; Eriksson, L.; Andersson, A.

    1985-01-01

    A commercial aerosol delivery system for ventilation scanning was evaluated in 23 patients with lung disease involving regional disturbances of ventilation. Ventilation scans obtained after inhalation of an aerosol labeled with In-113m were compared with Kr-81m ventilation scans. An indirect comparison was also made with a settling bag technique. There was close agreement between the aerosol and the Kr-81m ventilation scans in all of the patients. The aerosol outlined the ventilated parts of the lung adequately, and central deposition of particles was minimal. The penetration of the aerosol into the lung was higher with the delivery system that with a settling bag system. The aerosol delivery system appears suitable for clinical pulmonary ventilation scintigraphy

  6. Monitoring of the release of gaseous and aerosol-bound radioactive materials. Pt. 2

    International Nuclear Information System (INIS)

    1992-01-01

    KTA 1503 contains requirements on technical installations and supplementary organizational measures considered necessary in order to monitor the release of gaseous and aerosol-bound radioactive materials. It consists of part 1: Monitoring of the release of radioactive materials together with stack gas during normal operation; part 2: Monitoring of the release of radioactive materials together with stack gas in the event of incidents; part 3: Monitoring of radioactive materials not released together with stack gas. The concept on which this rule is based is to ensure that in the case of incidents during which the result of effluent monitoring remains meaningful, such monitoring can be reliably performed. (orig./HSCH) [de

  7. Improving the UNC Passive Aerosol Sampler Model Based on Comparison with Commonly Used Aerosol Sampling Methods.

    Science.gov (United States)

    Shirdel, Mariam; Andersson, Britt M; Bergdahl, Ingvar A; Sommar, Johan N; Wingfors, Håkan; Liljelind, Ingrid E

    2018-03-12

    In an occupational environment, passive sampling could be an alternative to active sampling with pumps for sampling of dust. One passive sampler is the University of North Carolina passive aerosol sampler (UNC sampler). It is often analysed by microscopic imaging. Promising results have been shown for particles above 2.5 µm, but indicate large underestimations for PM2.5. The aim of this study was to evaluate, and possibly improve, the UNC sampler for stationary sampling in a working environment. Sampling was carried out at 8-h intervals during 24 h in four locations in an open pit mine with UNC samplers, respirable cyclones, PM10 and PM2.5 impactors, and an aerodynamic particle sizer (APS). The wind was minimal. For quantification, two modifications of the UNC sampler analysis model, UNC sampler with hybrid model and UNC sampler with area factor, were compared with the original one, UNC sampler with mesh factor derived from wind tunnel experiments. The effect of increased resolution for the microscopic imaging was examined. Use of the area factor and a higher resolution eliminated the underestimation for PM10 and PM2.5. The model with area factor had the overall lowest deviation versus the impactor and the cyclone. The intraclass correlation (ICC) showed that the UNC sampler had a higher precision and better ability to distinguish between different exposure levels compared to the cyclone (ICC: 0.51 versus 0.24), but lower precision compared to the impactor (PM10: 0.79 versus 0.99; PM2.5: 0.30 versus 0.45). The particle size distributions as calculated from the different UNC sampler analysis models were visually compared with the distributions determined by APS. The distributions were obviously different when the UNC sampler with mesh factor was used but came to a reasonable agreement when the area factor was used. High resolution combined with a factor based on area only, results in no underestimation of small particles compared to impactors and cyclones and a

  8. Analysis od aerosol optical depth retrieved by MODIS and MERIS and comparison with photometer data

    International Nuclear Information System (INIS)

    Bocci, E.; Bonafoni, S.; Basili, P.; Biondi, R.; Arino, O.

    2009-01-01

    In this work a validation of aerosol optical depth (AOD) value provided by two different satellite sensor (MODIS and MERIS) is proposed. A comparison between satellite and ground-based AERONET data is carried out to verify the reliability of space borne instruments. Finally the behavior of AOD is analyzed monitoring particular events such as desert dust transport occurred on the 9 of October 2004 over the Mediterranean [it

  9. Online Simulations of Global Aerosol Distributions in the NASA GEOS-4 Model and Comparisons to Satellite and Ground-Based Aerosol Optical Depth

    Science.gov (United States)

    Colarco, Peter; daSilva, Arlindo; Chin, Mian; Diehl, Thomas

    2010-01-01

    We have implemented a module for tropospheric aerosols (GO CART) online in the NASA Goddard Earth Observing System version 4 model and simulated global aerosol distributions for the period 2000-2006. The new online system offers several advantages over the previous offline version, providing a platform for aerosol data assimilation, aerosol-chemistry-climate interaction studies, and short-range chemical weather forecasting and climate prediction. We introduce as well a methodology for sampling model output consistently with satellite aerosol optical thickness (AOT) retrievals to facilitate model-satellite comparison. Our results are similar to the offline GOCART model and to the models participating in the AeroCom intercomparison. The simulated AOT has similar seasonal and regional variability and magnitude to Aerosol Robotic Network (AERONET), Moderate Resolution Imaging Spectroradiometer, and Multiangle Imaging Spectroradiometer observations. The model AOT and Angstrom parameter are consistently low relative to AERONET in biomass-burning-dominated regions, where emissions appear to be underestimated, consistent with the results of the offline GOCART model. In contrast, the model AOT is biased high in sulfate-dominated regions of North America and Europe. Our model-satellite comparison methodology shows that diurnal variability in aerosol loading is unimportant compared to sampling the model where the satellite has cloud-free observations, particularly in sulfate-dominated regions. Simulated sea salt burden and optical thickness are high by a factor of 2-3 relative to other models, and agreement between model and satellite over-ocean AOT is improved by reducing the model sea salt burden by a factor of 2. The best agreement in both AOT magnitude and variability occurs immediately downwind of the Saharan dust plume.

  10. Aerosol material release rates from zircaloy-4 at temperatures from 2000 to 22000C

    International Nuclear Information System (INIS)

    Mulpuru, S.R.; Wren, D.J.; Rondeau, R.K.

    1987-01-01

    During some postulated severe accidents involving loss of coolant and loss of emergency coolant injection, the temperatures in a CANDU reactor fuel channel become high enough to cause failure and melting of the Zircaloy fuel cladding. At such high temperatures, vapors of fission products and structural (fuel and cladding) materials will be released into the coolant steam and hydrogen mixture. These vapors will condense as cooler conditions are encountered downstream. The vapors from structural materials are relatively involatile; therefore, they will condense readily into aerosol particles. These particles, in turn, will provide sites for the condensation of the more volatile fission products. The aerosol transport of fission products in the primary heat transport system (PHTS) will thus be influenced by the structural material release rates. As part of an ongoing program to develop predictive tools for aerosol and associated fission product transport through the PHTS, experiments have been conducted to measure the vapor mass release rates of the alloying elements from Zircaloy-4 at high temperatures. The paper presents the results and analysis of these experiments

  11. Comparison of Aerosol Classification From Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

    Science.gov (United States)

    Burton, Sharon P.; Ferrare, Rich A.; Omar, Ali H.; Vaughan, Mark A.; Rogers, Raymond R.; Hostetler, Chris a.; Hair, Johnathan W.; Obland, Michael D.; Butler, Carolyn F.; Cook, Anthony L.; hide

    2012-01-01

    Knowledge of aerosol composition and vertical distribution is crucial for assessing the impact of aerosols on climate. In addition, aerosol classification is a key input to CALIOP aerosol retrievals, since CALIOP requires an inference of the lidar ratio in order to estimate the effects of aerosol extinction and backscattering. In contrast, the NASA airborne HSRL-1 directly measures both aerosol extinction and backscatter, and therefore the lidar ratio (extinction-to-backscatter ratio). Four aerosol intensive properties from HSRL-1 are combined to infer aerosol type. Aerosol classification results from HSRL-1 are used here to validate the CALIOP aerosol type inferences.

  12. A Comparison of Gravimetric and Photometric Aerosol Samplers

    Science.gov (United States)

    2009-03-24

    the potential to cause disease (Vincent, 2007; Meldrum , 1996; and ATSDR, 2001). f) Fog – discernible mist that floats in air and usually settles to...atomization, such as spraying or arising from acid baths in chrome plating. The droplets are homogenous with the parent material and range from xvi...Contaminant Control. Boston, Butterworth Publishers. Meldrum , M. (1996). Review of fibre toxicology. H.S.E. Report, London, UK, Health and Safety

  13. Interactions of liquid lithium with various atmospheres, concretes, and insulating materials; and filtration of lithium aerosols

    International Nuclear Information System (INIS)

    Jeppson, D.W.

    1979-06-01

    This report describes the facilities and experiments and presents test results of a program being conducted at the hanford Engineering Development Laboratory (HEDL) in support of the fusion reactor development effort. This experimental program is designed to characterize the interaction of liquid lithium with various atmospheres, concretes, and insulating materials. Lithium-atmosphere reaction tests were conducted in normal humidity air, pure nitrogen, and carbon dioxide. These tests are described and their results, such as maximum temperatures, aerosol generated, and reaction rates measured, are reported. Initial lithium temperatures for these tests ranged between 224 0 C and 843 0 C. A lithium-concrete reaction test, using 10 kg of lithium at 327 0 C, and lithium-insulating materials reaction tests, using a few grams of lithium at 350 0 C and 600 0 C, are also described and results are presented. In addition, a lithium-aerosol filter loading test was conducted to determine the mass loading capacity of a commercial high efficiency particulate air (HEPA) filter. The aerosol was characterized, and the loading-capacity-versus-pressure-buildup across the filter is reported

  14. Stratospheric Aerosol and Gas Experiments 1 and 2: Comparisons with ozonesondes

    Science.gov (United States)

    Veiga, Robert E.; Cunnold, Derek M.; Chu, William P.; McCormick, M. Patrick

    1995-01-01

    Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE) 1 and 2 are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE 2 overpasses were computed down to 11.5 km in midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE 1 overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 +/- 2% for SAGE 2 and 8 +/- 3% for SAGE 1. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE 2, 70% were less than 5%, whereas for SAGE 1, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and -20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the SAGE 2 ozone retrieval for the levels of extinction encountered in the lower stratosphere during 1984 to mid-1991.

  15. Results from the Fourth WMO Filter Radiometer Comparison for aerosol optical depth measurements

    Science.gov (United States)

    Kazadzis, Stelios; Kouremeti, Natalia; Diémoz, Henri; Gröbner, Julian; Forgan, Bruce W.; Campanelli, Monica; Estellés, Victor; Lantz, Kathleen; Michalsky, Joseph; Carlund, Thomas; Cuevas, Emilio; Toledano, Carlos; Becker, Ralf; Nyeki, Stephan; Kosmopoulos, Panagiotis G.; Tatsiankou, Viktar; Vuilleumier, Laurent; Denn, Frederick M.; Ohkawara, Nozomu; Ijima, Osamu; Goloub, Philippe; Raptis, Panagiotis I.; Milner, Michael; Behrens, Klaus; Barreto, Africa; Martucci, Giovanni; Hall, Emiel; Wendell, James; Fabbri, Bryan E.; Wehrli, Christoph

    2018-03-01

    This study presents the results of the Fourth Filter Radiometer Comparison that was held in Davos, Switzerland, between 28 September and 16 October 2015. Thirty filter radiometers and spectroradiometers from 12 countries participated including reference instruments from global aerosol networks. The absolute differences of all instruments compared to the reference have been based on the World Meteorological Organization (WMO) criterion defined as follows: 95% of the measured data has to be within 0.005 ± 0.001/m (where m is the air mass). At least 24 out of 29 instruments achieved this goal at both 500 and 865 nm, while 12 out of 17 and 13 out of 21 achieved this at 368 and 412 nm, respectively. While searching for sources of differences among different instruments, it was found that all individual differences linked to Rayleigh, NO2, ozone, water vapor calculations and related optical depths and air mass calculations were smaller than 0.01 in aerosol optical depth (AOD) at 500 and 865 nm. Different cloud-detecting algorithms used have been compared. Ångström exponent calculations showed relatively large differences among different instruments, partly because of the high calculation uncertainty of this parameter in low AOD conditions. The overall low deviations of these AOD results and the high accuracy of reference aerosol network instruments demonstrated a promising framework to achieve homogeneity, compatibility and harmonization among the different spectral AOD networks in the near future.

  16. Fragrance materials in asthma: a pilot study using a surrogate aerosol product.

    Science.gov (United States)

    Vethanayagam, Dilini; Vliagoftis, Harissios; Mah, Dennell; Beach, Jeremy; Smith, Ladd; Moqbel, Redwan

    2013-11-01

    Many household products contain fragrances. Little is known about exposure to fragrances on human health, particularly within the airways. This study aimed to evaluate how common household fragrance products (i.e. air fresheners, cleaning products) affect people with asthma, who frequently report sensitivity to these products. Many of these products have volatile organic compounds or semi-volatile organic compounds. This study evaluated nine fragrance materials in an aerosol formulation to assess effects on airway physiology, airway inflammation and symptom perception in normal controls and those with asthma. The effects of fragrances were evaluated in people without asthma, people with mild asthma and people with moderate asthma in a four-way crossover placebo-controlled study. Subjects were exposed twice to a fragranced aerosol and twice to a placebo aerosol (15 and 30 min each). Subjects completed a questionnaire for 29 symptoms during and up to 3 h after each exposure scenario. Spirometry was performed prior to and 3 h post-exposure; sputum induction was conducted 3 h post-exposure. Nasal symptoms showed the greatest frequency of response in all three subject groups, and moderate asthmatics reported the greatest symptom severity and symptom types. No significant differences were noted in physiology or cellular inflammation. A trend for increased symptoms was noted in moderate asthmatics, suggesting that asthma severity may play a factor in fragrance sensitivity.

  17. Compact Layers of Hybrid Halide Perovskites Fabricated via the Aerosol Deposition Process-Uncoupling Material Synthesis and Layer Formation.

    Science.gov (United States)

    Panzer, Fabian; Hanft, Dominik; Gujar, Tanaji P; Kahle, Frank-Julian; Thelakkat, Mukundan; Köhler, Anna; Moos, Ralf

    2016-04-08

    We present the successful fabrication of CH₃NH₃PbI₃ perovskite layers by the aerosol deposition method (ADM). The layers show high structural purity and compactness, thus making them suitable for application in perovskite-based optoelectronic devices. By using the aerosol deposition method we are able to decouple material synthesis from layer processing. Our results therefore allow for enhanced and easy control over the fabrication of perovskite-based devices, further paving the way for their commercialization.

  18. Simultaneous polarimeter retrievals of microphysical aerosol and ocean color parameters from the "MAPP" algorithm with comparison to high-spectral-resolution lidar aerosol and ocean products.

    Science.gov (United States)

    Stamnes, S; Hostetler, C; Ferrare, R; Burton, S; Liu, X; Hair, J; Hu, Y; Wasilewski, A; Martin, W; van Diedenhoven, B; Chowdhary, J; Cetinić, I; Berg, L K; Stamnes, K; Cairns, B

    2018-04-01

    We present an optimal-estimation-based retrieval framework, the microphysical aerosol properties from polarimetry (MAPP) algorithm, designed for simultaneous retrieval of aerosol microphysical properties and ocean color bio-optical parameters using multi-angular total and polarized radiances. Polarimetric measurements from the airborne NASA Research Scanning Polarimeter (RSP) were inverted by MAPP to produce atmosphere and ocean products. The RSP MAPP results are compared with co-incident lidar measurements made by the NASA High-Spectral-Resolution Lidar HSRL-1 and HSRL-2 instruments. Comparisons are made of the aerosol optical depth (AOD) at 355 and 532 nm, lidar column-averaged measurements of the aerosol lidar ratio and Ångstrøm exponent, and lidar ocean measurements of the particulate hemispherical backscatter coefficient and the diffuse attenuation coefficient. The measurements were collected during the 2012 Two-Column Aerosol Project (TCAP) campaign and the 2014 Ship-Aircraft Bio-Optical Research (SABOR) campaign. For the SABOR campaign, 73% RSP MAPP retrievals fall within ±0.04 AOD at 532 nm as measured by HSRL-1, with an R value of 0.933 and root-mean-square deviation of 0.0372. For the TCAP campaign, 53% of RSP MAPP retrievals are within 0.04 AOD as measured by HSRL-2, with an R value of 0.927 and root-mean-square deviation of 0.0673. Comparisons with HSRL-2 AOD at 355 nm during TCAP result in an R value of 0.959 and a root-mean-square deviation of 0.0694. The RSP retrievals using the MAPP optimal estimation framework represent a key milestone on the path to a combined lidar + polarimeter retrieval using both HSRL and RSP measurements.

  19. Aerosol formation from high-velocity uranium drops: Comparison of number and mass distributions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rader, D.J.; Benson, D.A.

    1995-05-01

    This report presents the results of an experimental study of the aerosol produced by the combustion of high-velocity molten-uranium droplets produced by the simultaneous heating and electromagnetic launch of uranium wires. These tests are intended to simulate the reduction of high-velocity fragments into aerosol in high-explosive detonations or reactor accidents involving nuclear materials. As reported earlier, the resulting aerosol consists mainly of web-like chain agglomerates. A condensation nucleus counter was used to investigate the decay of the total particle concentration due to coagulation and losses. Number size distributions based on mobility equivalent diameter obtained soon after launch with a Differential Mobility Particle Sizer showed lognormal distributions with an initial count median diameter (CMD) of 0.3 {mu}m and a geometric standard deviation, {sigma}{sub g} of about 2; the CMD was found to increase and {sigma}{sub g} decrease with time due to coagulation. Mass size distributions based on aerodynamic diameter were obtained for the first time with a Microorifice Uniform Deposit Impactor, which showed lognormal distributions with mass median aerodynamic diameters of about 0.5 {mu}m and an aerodynamic geometric standard deviation of about 2. Approximate methods for converting between number and mass distributions and between mobility and aerodynamic equivalent diameters are presented.

  20. Aerosol formation from high-velocity uranium drops: Comparison of number and mass distributions. Final report

    International Nuclear Information System (INIS)

    Rader, D.J.; Benson, D.A.

    1995-05-01

    This report presents the results of an experimental study of the aerosol produced by the combustion of high-velocity molten-uranium droplets produced by the simultaneous heating and electromagnetic launch of uranium wires. These tests are intended to simulate the reduction of high-velocity fragments into aerosol in high-explosive detonations or reactor accidents involving nuclear materials. As reported earlier, the resulting aerosol consists mainly of web-like chain agglomerates. A condensation nucleus counter was used to investigate the decay of the total particle concentration due to coagulation and losses. Number size distributions based on mobility equivalent diameter obtained soon after launch with a Differential Mobility Particle Sizer showed lognormal distributions with an initial count median diameter (CMD) of 0.3 μm and a geometric standard deviation, σ g of about 2; the CMD was found to increase and σ g decrease with time due to coagulation. Mass size distributions based on aerodynamic diameter were obtained for the first time with a Microorifice Uniform Deposit Impactor, which showed lognormal distributions with mass median aerodynamic diameters of about 0.5 μm and an aerodynamic geometric standard deviation of about 2. Approximate methods for converting between number and mass distributions and between mobility and aerodynamic equivalent diameters are presented

  1. Direct Aerosol Radiative Forcing from Combined A-Train Observations - Preliminary Comparisons with AeroCom Models and Pathways to Observationally Based All-sky Estimates

    Science.gov (United States)

    Redemann, J.; Livingston, J. M.; Shinozuka, Y.; Kacenelenbogen, M. S.; Russell, P. B.; LeBlanc, S. E.; Vaughan, M.; Ferrare, R. A.; Hostetler, C. A.; Rogers, R. R.; Burton, S. P.; Torres, O.; Remer, L. A.; Stier, P.; Schutgens, N.

    2014-12-01

    We describe a technique for combining CALIOP aerosol backscatter, MODIS spectral AOD (aerosol optical depth), and OMI AAOD (absorption aerosol optical depth) retrievals for the purpose of estimating full spectral sets of aerosol radiative properties, and ultimately for calculating the 3-D distribution of direct aerosol radiative forcing. We present results using one year of data collected in 2007 and show comparisons of the aerosol radiative property estimates to collocated AERONET retrievals. Use of the recently released MODIS Collection 6 data for aerosol optical depths derived with the dark target and deep blue algorithms has extended the coverage of the multi-sensor estimates towards higher latitudes. Initial calculations of seasonal clear-sky aerosol radiative forcing based on our multi-sensor aerosol retrievals compare well with over-ocean and top of the atmosphere IPCC-2007 model-based results, and with more recent assessments in the "Climate Change Science Program Report: Atmospheric Aerosol Properties and Climate Impacts" (2009). For the first time, we present comparisons of our multi-sensor aerosol direct radiative forcing estimates to values derived from a subset of models that participated in the latest AeroCom initiative. We discuss the major challenges that exist in extending our clear-sky results to all-sky conditions. On the basis of comparisons to suborbital measurements, we present some of the limitations of the MODIS and CALIOP retrievals in the presence of adjacent or underlying clouds. Strategies for meeting these challenges are discussed.

  2. [Filtering facepieces: effect of oily aerosol load on penetration through the filtering material].

    Science.gov (United States)

    Plebani, Carmela; Listrani, S; Di Luigi, M

    2010-01-01

    Electrostatic filters are widely used in applications requiring high filtration efficiency and low pressure drop. However various studies showed that the penetration through electrostatic filters increases during exposure to an aerosol flow. This study investigates the effects of prolonged exposure to an oily aerosol on the penetration through filtering facepieces available on the market. Some samples of FFP1, FFP2 and FFP3 filtering facepieces were exposed for 8 hours consecutively to a paraffin oil polydisperse aerosol. At the end of the exposure about 830 mg of paraffin oil were deposited in the facepiece. All the examined facepieces showed penetration values that increased with paraffin oil load while pressure drop values were substantially the same before and after exposure. The measured maximum penetration values did not exceed the maximum penetration values allowed by the European technical standards, except in one case. According to the literature, 830 mg of oil load in a facepiece is not feasible in workplaces over an eight- hour shift. However, the trend of the penetration versus exposure mass suggests that if the load increases, the penetration may exceed the maximum allowed values. For comparison a mechanical filter was also studied. This showed an initial pressure drop higher than FFP2 filtering facepieces characterized by comparable penetration values. During exposure the pressure drop virtually doubled while penetration did not change. The increase in penetration with no increase in pressure drop in the analyzed facepieces indicates that it is necessary to comply with the information supplied by the manufacturer that restricts their use to a single shift.

  3. Spatial distribution analysis of the OMI aerosol layer height: a pixel-by-pixel comparison to CALIOP observations

    Science.gov (United States)

    Chimot, Julien; Pepijn Veefkind, J.; Vlemmix, Tim; Levelt, Pieternel F.

    2018-04-01

    A global picture of atmospheric aerosol vertical distribution with a high temporal resolution is of key importance not only for climate, cloud formation, and air quality research studies but also for correcting scattered radiation induced by aerosols in absorbing trace gas retrievals from passive satellite sensors. Aerosol layer height (ALH) was retrieved from the OMI 477 nm O2 - O2 band and its spatial pattern evaluated over selected cloud-free scenes. Such retrievals benefit from a synergy with MODIS data to provide complementary information on aerosols and cloudy pixels. We used a neural network approach previously trained and developed. Comparison with CALIOP aerosol level 2 products over urban and industrial pollution in eastern China shows consistent spatial patterns with an uncertainty in the range of 462-648 m. In addition, we show the possibility to determine the height of thick aerosol layers released by intensive biomass burning events in South America and Russia from OMI visible measurements. A Saharan dust outbreak over sea is finally discussed. Complementary detailed analyses show that the assumed aerosol properties in the forward modelling are the key factors affecting the accuracy of the results, together with potential cloud residuals in the observation pixels. Furthermore, we demonstrate that the physical meaning of the retrieved ALH scalar corresponds to the weighted average of the vertical aerosol extinction profile. These encouraging findings strongly suggest the potential of the OMI ALH product, and in more general the use of the 477 nm O2 - O2 band from present and future similar satellite sensors, for climate studies as well as for future aerosol correction in air quality trace gas retrievals.

  4. Spatial distribution analysis of the OMI aerosol layer height: a pixel-by-pixel comparison to CALIOP observations

    Directory of Open Access Journals (Sweden)

    J. Chimot

    2018-04-01

    Full Text Available A global picture of atmospheric aerosol vertical distribution with a high temporal resolution is of key importance not only for climate, cloud formation, and air quality research studies but also for correcting scattered radiation induced by aerosols in absorbing trace gas retrievals from passive satellite sensors. Aerosol layer height (ALH was retrieved from the OMI 477 nm O2 − O2 band and its spatial pattern evaluated over selected cloud-free scenes. Such retrievals benefit from a synergy with MODIS data to provide complementary information on aerosols and cloudy pixels. We used a neural network approach previously trained and developed. Comparison with CALIOP aerosol level 2 products over urban and industrial pollution in eastern China shows consistent spatial patterns with an uncertainty in the range of 462–648 m. In addition, we show the possibility to determine the height of thick aerosol layers released by intensive biomass burning events in South America and Russia from OMI visible measurements. A Saharan dust outbreak over sea is finally discussed. Complementary detailed analyses show that the assumed aerosol properties in the forward modelling are the key factors affecting the accuracy of the results, together with potential cloud residuals in the observation pixels. Furthermore, we demonstrate that the physical meaning of the retrieved ALH scalar corresponds to the weighted average of the vertical aerosol extinction profile. These encouraging findings strongly suggest the potential of the OMI ALH product, and in more general the use of the 477 nm O2 − O2 band from present and future similar satellite sensors, for climate studies as well as for future aerosol correction in air quality trace gas retrievals.

  5. Experimental study of radioactive aerosols emission during the thermal degradation of organic materials in nuclear facilities

    International Nuclear Information System (INIS)

    Fernandez, Yvette

    1993-01-01

    Radioactive products may be released during a fire in nuclear fuel cycles facilities. These products must be confined to avoid a contamination spread in the environment. It is therefore necessary to be able to predict the amount and the physico-chemical forms of radioactive material that may be airborne. The aim of this study is to determine experimentally the release of contamination aerosols in a typical fire scenario involving plutonium oxide in a glove box. Firstly, this phenomenon has been studied in a small scale test chamber where samples of polymethylmethacrylate (Plexiglas) contaminated by cerium oxide (used as a substitute for plutonium oxide) were submitted to thermal degradation (pyrolysis and combustion). The release of radioactive material is determined by the quantity of contaminant emitted, the kinetics of the release and the particle size distribution of aerosols. Secondly, the development of an experimental procedure allowed to realize large scale fires in more realistic conditions. The experimental tools developed in the course of this study allow to consider application to other scenarios. (author) [fr

  6. Retrieval of Aerosol Components Using Multi-Wavelength Mie-Raman Lidar and Comparison with Ground Aerosol Sampling

    Directory of Open Access Journals (Sweden)

    Yukari Hara

    2018-06-01

    Full Text Available We verified an algorithm using multi-wavelength Mie-Raman lidar (MMRL observations to retrieve four aerosol components (black carbon (BC, sea salt (SS, air pollution (AP, and mineral dust (DS with in-situ aerosol measurements, and determined the seasonal variation of aerosol components in Fukuoka, in the western region of Japan. PM2.5, PM10, and mass concentrations of BC and SS components are derived from in-situ measurements. MMRL provides the aerosol extinction coefficient (α, particle linear depolarization ratio (δ, backscatter coefficient (β, and lidar ratio (S at 355 and 532 nm, and the attenuated backscatter coefficient (βatt at 1064 nm. We retrieved vertical distributions of extinction coefficients at 532 nm for four aerosol components (BC, SS, AP, and DS using 1α532 + 1β532 + 1βatt,1064 + 1δ532 data of MMRL. The retrieved extinction coefficients of the four aerosol components at 532 nm were converted to mass concentrations using the theoretical computed conversion factor assuming the prescribed size distribution, particle shape, and refractive index for each aerosol component. MMRL and in-situ measurements confirmed that seasonal variation of aerosol optical properties was affected by internal/external mixing of various aerosol components, in addition to hygroscopic growth of water-soluble aerosols. MMRL overestimates BC mass concentration compared to in-situ observation using the pure BC model. This overestimation was reduced drastically by introducing the internal mixture model of BC and water-soluble substances (Core-Gray Shell (CGS model. This result suggests that considering the internal mixture of BC and water-soluble substances is essential for evaluating BC mass concentration in this area. Systematic overestimation of BC mass concentration was found during summer, even when we applied the CGS model. The observational facts based on in-situ and MMRL measurements suggested that misclassification of AP as CGS particles was

  7. A-Train Aerosol Observations Preliminary Comparisons with AeroCom Models and Pathways to Observationally Based All-Sky Estimates

    Science.gov (United States)

    Redemann, J.; Livingston, J.; Shinozuka, Y.; Kacenelenbogen, M.; Russell, P.; LeBlanc, S.; Vaughan, M.; Ferrare, R.; Hostetler, C.; Rogers, R.; hide

    2014-01-01

    We have developed a technique for combining CALIOP aerosol backscatter, MODIS spectral AOD (aerosol optical depth), and OMI AAOD (absorption aerosol optical depth) retrievals for the purpose of estimating full spectral sets of aerosol radiative properties, and ultimately for calculating the 3-D distribution of direct aerosol radiative forcing. We present results using one year of data collected in 2007 and show comparisons of the aerosol radiative property estimates to collocated AERONET retrievals. Use of the recently released MODIS Collection 6 data for aerosol optical depths derived with the dark target and deep blue algorithms has extended the coverage of the multi-sensor estimates towards higher latitudes. We compare the spatio-temporal distribution of our multi-sensor aerosol retrievals and calculations of seasonal clear-sky aerosol radiative forcing based on the aerosol retrievals to values derived from four models that participated in the latest AeroCom model intercomparison initiative. We find significant inter-model differences, in particular for the aerosol single scattering albedo, which can be evaluated using the multi-sensor A-Train retrievals. We discuss the major challenges that exist in extending our clear-sky results to all-sky conditions. On the basis of comparisons to suborbital measurements, we present some of the limitations of the MODIS and CALIOP retrievals in the presence of adjacent or underlying clouds. Strategies for meeting these challenges are discussed.

  8. Social comparison, personal relative deprivation, and materialism.

    Science.gov (United States)

    Kim, Hyunji; Callan, Mitchell J; Gheorghiu, Ana I; Matthews, William J

    2017-06-01

    Across five studies, we found consistent evidence for the idea that personal relative deprivation (PRD), which refers to resentment stemming from the belief that one is deprived of deserved outcomes compared to others, uniquely contributes to materialism. In Study 1, self-reports of PRD positively predicted materialistic values over and above socioeconomic status, personal power, self-esteem, and emotional uncertainty. The experience of PRD starts with social comparison, and Studies 2 and 3 found that PRD mediated the positive relation between a tendency to make social comparisons of abilities and materialism. In Study 4, participants who learned that they had less (vs. similar) discretionary income than people like them reported a stronger desire for more money relative to donating more to charity. In Study 5, during a windfall-spending task, participants higher in PRD spent more on things they wanted relative to other spending categories (e.g., paying off debts). © 2016 The Authors. British Journal of Social Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.

  9. Aerosol Size Distributions During ACE-Asia: Retrievals From Optical Thickness and Comparisons With In-situ Measurements

    Science.gov (United States)

    Kuzmanoski, M.; Box, M.; Box, G. P.; Schmidt, B.; Russell, P. B.; Redemann, J.; Livingston, J. M.; Wang, J.; Flagan, R. C.; Seinfeld, J. H.

    2002-12-01

    As part of the ACE-Asia experiment, conducted off the coast of China, Korea and Japan in spring 2001, measurements of aerosol physical, chemical and radiative characteristics were performed aboard the Twin Otter aircraft. Of particular importance for this paper were spectral measurements of aerosol optical thickness obtained at 13 discrete wavelengths, within 354-1558 nm wavelength range, using the AATS-14 sunphotometer. Spectral aerosol optical thickness can be used to obtain information about particle size distribution. In this paper, we use sunphotometer measurements to retrieve size distribution of aerosols during ACE-Asia. We focus on four cases in which layers influenced by different air masses were identified. Aerosol optical thickness of each layer was inverted using two different techniques - constrained linear inversion and multimodal. In the constrained linear inversion algorithm no assumption about the mathematical form of the distribution to be retrieved is made. Conversely, the multimodal technique assumes that aerosol size distribution is represented as a linear combination of few lognormal modes with predefined values of mode radii and geometric standard deviations. Amplitudes of modes are varied to obtain best fit of sum of optical thicknesses due to individual modes to sunphotometer measurements. In this paper we compare the results of these two retrieval methods. In addition, we present comparisons of retrieved size distributions with in situ measurements taken using an aerodynamic particle sizer and differential mobility analyzer system aboard the Twin Otter aircraft.

  10. Comparisons of aerosol optical depth provided by seviri satellite observations and CAMx air quality modelling

    Science.gov (United States)

    Fernandes, A.; Riffler, M.; Ferreira, J.; Wunderle, S.; Borrego, C.; Tchepel, O.

    2015-04-01

    Satellite data provide high spatial coverage and characterization of atmospheric components for vertical column. Additionally, the use of air pollution modelling in combination with satellite data opens the challenging perspective to analyse the contribution of different pollution sources and transport processes. The main objective of this work is to study the AOD over Portugal using satellite observations in combination with air pollution modelling. For this purpose, satellite data provided by Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) on-board the geostationary Meteosat-9 satellite on AOD at 550 nm and modelling results from the Chemical Transport Model (CAMx - Comprehensive Air quality Model) were analysed. The study period was May 2011 and the aim was to analyse the spatial variations of AOD over Portugal. In this study, a multi-temporal technique to retrieve AOD over land from SEVIRI was used. The proposed method takes advantage of SEVIRI's high temporal resolution of 15 minutes and high spatial resolution. CAMx provides the size distribution of each aerosol constituent among a number of fixed size sections. For post processing, CAMx output species per size bin have been grouped into total particulate sulphate (PSO4), total primary and secondary organic aerosols (POA + SOA), total primary elemental carbon (PEC) and primary inert material per size bin (CRST1 to CRST_4) to be used in AOD quantification. The AOD was calculated by integration of aerosol extinction coefficient (Qext) on the vertical column. The results were analysed in terms of temporal and spatial variations. The analysis points out that the implemented methodology provides a good spatial agreement between modelling results and satellite observation for dust outbreak studied (10th -17th of May 2011). A correlation coefficient of r=0.79 was found between the two datasets. This work provides relevant background to start the integration of these two different types of the data in order

  11. International Standard Problem 40 - Aerosol Deposition and Resuspension. Final Comparison Report

    International Nuclear Information System (INIS)

    De Los Reyes, Alfredo Castelo; Areia Capitao, Joaquim; De Santi, Giovanni

    1999-02-01

    -October 1997 and the deadline for submission of the results of this second phase was the end of January 1998. A first draft of this comparison report was produced in March 1998, followed by a workshop in Ispra in mid-March. Two errors in the supplied data had been detected and were communicated to the participants in this workshop, one concerning the steam flow rate in the deposition phase of the exercise and the other the size distribution of the resuspended aerosols in the resuspension phase. The decision whether or not to re-do their calculations was left to the each ISP participant and the deadline for the submission of new results, with these or other modifications relative to the previous ones, was the end of May 1998. These new calculations, having been performed in open conditions, are presented separately in this report. The final draft of the comparison report was distribute in June 1998, followed by a final workshop in Ispra the same month. This report is divided into six main sections, one concerning the experimental set-up and results, two each for the deposition and resuspension phases of the International Standard Problem (blind and open calculations), and one on general conclusions and recommendations. According to the opinion of the ISP participants, the results in the two sections on the deposition and resuspension exercises are listed by computer code and, for each code, by organisation. The calculations submitted by the Joint Research Centre are included together with the others. Although the JRC staff who performed the calculations did not have access to the experimental results before submitting their results, their knowledge of the facility puts their calculations in a separate class

  12. The aerosol distribution in Europe derived with the Community Multiscale Air Quality (CMAQ) model: comparison to near surface in situ and sunphotometer measurements

    OpenAIRE

    Matthias , V.

    2008-01-01

    The aerosol distribution in Europe was simulated with the Community Multiscale Air Quality (CMAQ) model system version 4.5 for the years 2000 and 2001. The results were compared with daily averages of PM10 measurements taken in the framework of EMEP and with aerosol optical depth (AOD) values measured within AERONET. The modelled total aerosol mass is typically about 30–60% lower than the corresponding measurements. However a comparison of the chemical composition of th...

  13. Comparison of Coincident Multiangle Imaging Spectroradiometer and Moderate Resolution Imaging Spectroradiometer Aerosol Optical Depths over Land and Ocean Scenes Containing Aerosol Robotic Network Sites

    Science.gov (United States)

    Abdou, Wedad A.; Diner, David J.; Martonchik, John V.; Bruegge, Carol J.; Kahn, Ralph A.; Gaitley, Barbara J.; Crean, Kathleen A.; Remer, Lorraine A.; Holben, Brent

    2005-01-01

    The Multiangle Imaging Spectroradiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS), launched on 18 December 1999 aboard the Terra spacecraft, are making global observations of top-of-atmosphere (TOA) radiances. Aerosol optical depths and particle properties are independently retrieved from these radiances using methodologies and algorithms that make use of the instruments corresponding designs. This paper compares instantaneous optical depths retrieved from simultaneous and collocated radiances measured by the two instruments at locations containing sites within the Aerosol Robotic Network (AERONET). A set of 318 MISR and MODIS images, obtained during the months of March, June, and September 2002 at 62 AERONET sites, were used in this study. The results show that over land, MODIS aerosol optical depths at 470 and 660 nm are larger than those retrieved from MISR by about 35% and 10% on average, respectively, when all land surface types are included in the regression. The differences decrease when coastal and desert areas are excluded. For optical depths retrieved over ocean, MISR is on average about 0.1 and 0.05 higher than MODIS in the 470 and 660 nm bands, respectively. Part of this difference is due to radiometric calibration and is reduced to about 0.01 and 0.03 when recently derived band-to-band adjustments in the MISR radiometry are incorporated. Comparisons with AERONET data show similar patterns.

  14. Modelling of Aerosol Chemistry and Transport over Europe and Comparison with Measurements

    NARCIS (Netherlands)

    Jeuken, A.; Veefkind, J.P.; Metzger, S.; Denter, F.; Velthoven, P.

    1999-01-01

    Because of the short lifetime of aerosols (days-weeks), the radiative forcing associated with aerosols varies strongly spatially and temporally (see van Dorland et al., poster) Current measurement networks of sulfate and other aerosol species are unable to provide a representative picture of the

  15. Comparison of Cloud and Aerosol Detection between CERES Edition 3 Cloud Mask and CALIPSO Version 2 Data Products

    Science.gov (United States)

    Trepte, Qing; Minnis, Patrick; Sun-Mack, Sunny; Trepte, Charles

    Clouds and aerosol play important roles in the global climate system. Accurately detecting their presence, altitude, and properties using satellite radiance measurements is a crucial first step in determining their influence on surface and top-of-atmosphere radiative fluxes. This paper presents a comparison analysis of a new version of the Clouds and Earth's Radiant Energy System (CERES) Edition 3 cloud detection algorithms using Aqua MODIS data with the recently released Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Version 2 Vertical Feature Mask (VFM). Improvements in CERES Edition 3 cloud mask include dust detection, thin cirrus tests, enhanced low cloud detection at night, and a smoother transition from mid-latitude to polar regions. For the CALIPSO Version 2 data set, changes to the lidar calibration can result in significant improvements to its identification of optically thick aerosol layers. The Aqua and CALIPSO satellites, part of the A-train satellite constellation, provide a unique opportunity for validating passive sensor cloud and aerosol detection using an active sensor. In this paper, individual comparison cases will be discussed for different types of clouds and aerosols over various surfaces, for daytime and nighttime conditions, and for regions ranging from the tropics to the poles. Examples will include an assessment of the CERES detection algorithm for optically thin cirrus, marine stratus, and polar night clouds as well as its ability to characterize Saharan dust plumes off the African coast. With the CALIPSO lidar's unique ability to probe the vertical structure of clouds and aerosol layers, it provides an excellent validation data set for cloud detection algorithms, especially for polar nighttime clouds.

  16. Compact Layers of Hybrid Halide Perovskites Fabricated via the Aerosol Deposition Process—Uncoupling Material Synthesis and Layer Formation

    Directory of Open Access Journals (Sweden)

    Fabian Panzer

    2016-04-01

    Full Text Available We present the successful fabrication of CH3NH3PbI3 perovskite layers by the aerosol deposition method (ADM. The layers show high structural purity and compactness, thus making them suitable for application in perovskite-based optoelectronic devices. By using the aerosol deposition method we are able to decouple material synthesis from layer processing. Our results therefore allow for enhanced and easy control over the fabrication of perovskite-based devices, further paving the way for their commercialization.

  17. Evaluation of sulfate aerosol optical depths over the North Atlantic and comparison with satellite observations

    International Nuclear Information System (INIS)

    Berkowitz, C.M.; Ghan, S.J.; Benkovitz, C.M.; Wagener, R.; Nemesure, S.; Schwartz, S.E.

    1993-11-01

    It has been postulated that scattering of sunlight by aerosols can significantly reduce the amount of solar energy absorbed by the climate system. Aerosol measurement programs alone cannot provide all the information needed to evaluate the radiative forcing due to anthropogenic aerosols. Thus, comprehensive global-scale aerosol models, properly validated against surface-based and satellite measurements, are a fundamental tool for evaluating the impacts of aerosols on the planetary radiation balance. Analyzed meteorological fields from the European Centre for Medium-Range Weather Forecasts are used to drive a modified version of the PNL Global Chemistry Model, applied to the atmospheric sulfur cycle. The resulting sulfate fields are used to calculate aerosol optical depths, which in turn are compared to estimates of aerosol optical depth based on satellite observations

  18. Comparison of methods for the quantification of the different carbon fractions in atmospheric aerosol samples

    Science.gov (United States)

    Nunes, Teresa; Mirante, Fátima; Almeida, Elza; Pio, Casimiro

    2010-05-01

    to evaluate the possibility of continue using, for trend analysis, the historical data set, we performed an inter-comparison between our method and an adaptation of EUSAAR-2 protocol, taking into account that this last protocol will possibly be recommended for analysing carbonaceous aerosols at European sites. In this inter-comparison we tested different types of samples (PM2,5, PM2,5-10, PM10) with large spectra of carbon loadings, with and without pre-treatment acidification. For a reduced number of samples, five replicates of each one were analysed by each method for statistical purposes. The inter-comparison study revealed that when the sample analysis were performed in similar room conditions, the two thermo-optic methods give similar results for TC, OC and EC, without significant differences at a 95% confidence level. The correlation between the methods, DAO and EUSAAR-2 for EC is smaller than for TC and OC, although showing a coefficient correlation over 0,95, with a slope close to one. For samples performed in different periods, room temperatures seem to have a significant effect over OC quantification. The sample pre-treatment with HCl fumigation tends to decrease TC quantification, mainly due to the more volatile organic fraction release during the first heating step. For a set of 20 domestic biomass burning samples analyzed by the DAO method we observed an average decrease in TC quantification of 3,7 % in relation to non-acidified samples, even though this decrease is accompanied by an average increase in the less volatile organic fraction. The indirect measurement of carbon carbonate, usually a minor carbon component in the carbonaceous aerosol, based on the difference between TC measured by TOM of acidified and non-acidified samples is not a robust measurement, considering the biases affecting his quantification. The present study show that the two thermo-optic temperature program used for OC and EC quantification give similar results, and if in the

  19. Modeling the Optical Properties of Biomass Burning Aerosols: Young Smoke Aerosols From Savanna Fires and Comparisons to Observations from SAFARI 2000

    Science.gov (United States)

    Matichuk, R. I.; Smith, J. A.; Toon, O. B.; Colarso, P. R.

    2006-01-01

    Annually, farmers in southern Africa manage their land resources and prepare their fields for cultivation by burning crop residual debris, with a peak in the burning season occurring during August and September. The emissions from these fires in southern Africa are among the greatest from fires worldwide, and the gases and aerosol particles produced adversely affect air quality large distances from their source regions, and can even be tracked in satellite imagery as they cross the Atlantic and Pacific Ocean basins. During August and September 2000 an international group of researchers participating in the Southern African Regional Science Initiate field experiment (SAFARI 2000) made extensive ground-based, airborne, and satellite measurements of these gases and aerosols in order to quantify their amounts and effects on Earth's atmosphere. In this study we interpreted the measurements of smoke aerosol particles made during SAFARI 2000 in order to better represent these particles in a numerical model simulating their transport and fate. Typically, smoke aerosols emitted from fires are concentrated by mass in particles about 0.3 micrometers in diameter (1,000,000 micrometers = 1 meter, about 3 feet); for comparison, the thickness of a human hair is about 50 micrometers, almost 200 times as great. Because of the size of these particles, at the surface they can be easily inhaled into the lungs, and in high concentrations have deleterious health effects on humans. Additionally, these particles reflect and absorb sunlight, impacting both visibility and the balance of sunlight reaching -Earth's surface, and ultimately play a role in modulating Earth's climate. Because of these important effects, it is important that numerical models used to estimate Earth's climate response to changes in atmospheric composition accurately represent the quantity and evolution of smoke particles. In our model, called the Community Aerosol and Radiation Model for Atmospheres (CARMA) we used

  20. Aerosol studies

    International Nuclear Information System (INIS)

    Cristy, G.A.; Fish, M.E.

    1978-01-01

    As part of the continuing studies of the effects of very severe reactor accidents, an effort was made to develop, test, and improve simple, effective, and inexpensive methods by which the average citizen, using only materials readily available, could protect his residence, himself, and his family from injury by toxic aerosols. The methods for protection against radioactive aerosols should be equally effective against a clandestine biological attack by terrorists. The results of the tests to date are limited to showing that spores of the harmless bacterium, bacillus globegii (BG), can be used as a simulant for the radioactive aerosols. An aerosol generator of Lauterbach type was developed which will produce an essentially monodisperse aerosol at the rate of 10 9 spores/min. Analytical techniques have been established which give reproducible results. Preliminary field tests have been conducted to check out the components of the system. Preliminary tests of protective devices, such as ordinary vacuum sweepers, have given protection factors of over 1000

  1. Comparison of efficacy of three different mouthwashes in reducing aerosol contamination produced by ultrasonic scaler: A pilot study

    Directory of Open Access Journals (Sweden)

    Shivam Yadav

    2018-01-01

    Full Text Available Background and Objective: Aerosol produced during the procedure of scaling and root planing is a potent source of infection. Preprocedural mouthrinsing has been found effective in reducing the bacterial load of the aerosol produced during the procedure. Thus, the aim of the present study was to evaluate and compare the efficacy of three different mouthwashes containing Chlorhexidine, Essential Oils & Herbal Extracts by using them as preprocedural rinsing agent in reducing the bacterial load of the aerosol produced by ultrasonic scaler. Material and Methodology: 40 subjects age and gender matched were randomly divided into four groups on the basis of agents used for preprocedural mouthrinsing - Group I: Distilled Water (Control, Group II: Chlorhexidine (CHX, Group III: Herbal Extracts (HR & Group IV: Essential Oils (EO. The aerosols were collected on three previously prepared and sterilised blood agar plates at three different positions in the operatory. The colony forming units were counted after incubating the plates for 48 hours. Result: At all locations, the mean CFU was highest in Group I followed by Group III, Group IV and Group II. Conclusion: In the study 0.2 % chlorhexidine was found to be most effective preprocedural mouthwash in reducing the bacterial load in the aerosol produced during ultrasonic scaling followed by essential oil and herbal mouthwash respectively.

  2. Comparison of aerosol inhalation lung images using BARC and other nebulizers

    International Nuclear Information System (INIS)

    Isawa, Toyoharu; Teshima, Takeo; Anazawa, Yoshiki; Miki, Makoto

    1994-01-01

    Various factors determine the site of inhaled aerosol deposition in the lungs. They are the size of aerosol the composition of carrier gas of the aerosol, the airflow rate, physico-chemical properties of the carrier gas or the aerosol, the shape and structure of the airways, and the body position during inhalation. Aerosol inhalation lung images were obtained in the same subjects using 99m Tc-human serum albumin aerosol generated by 3 different aerosol generators each producing different-sized aerosol and 2 or 3 days apart from each study. The size of aerosol produced by an ultrasonic nebulizer (Mistogen) was 1.93 Micron in activity median aerodynamic diameter (AMAD) with its geometric standard deviation (σg) of 1.73, that by a jet nebulizer (Ultra Vent) was 1.04 micron in AMAD with its σg of 1.71, and that by our BARC nebulizer, a type of a jet nebulizer, was 0.84 micron in AMAD with its σg of 1.73. In addition Technegas was also applied to selected patients. The latter produced aerosol of less than 0.2 micron in size at the largest and the majority, say, 95% or more of the generated aerosol was less than 0.1 micron in size by electron Microscopy. Each subject inhaled aerosol in resting tidal breathing through a mouth-piece with a one way double J valve with the nose clipped in the sitting position. After inhaling approximately 2-3 mCi (74 to 111 MBq) in the thorax, four view lung images were taken: anterior, posterior, and right and left laterals. 300 K counts per view were collected. They were not only pictured on polaroid films as analogue data but also recorded and stored in a computer as digital data. In case of Technegas breathing it for the RV (residual volume) to the TLC (total lung capacity) level followed by breath-holding for 5 to 10 sec in duration was repeated 2 to 3 times as a breathing maneuver instead of tidal breathing. Otherwise deposition efficiency of Technegas is very little because of the small size of the Technegas. Representative 10

  3. Inter-comparison of lidar and ceilometer retrievals for aerosol and Planetary Boundary Layer profiling over Athens, Greece

    Directory of Open Access Journals (Sweden)

    G. Tsaknakis

    2011-06-01

    Full Text Available This study presents an inter-comparison of two active remote sensors (lidar and ceilometer to determine the mixing layer height and structure of the Planetary Boundary Layer (PBL and to retrieve tropospheric aerosol vertical profiles over Athens, Greece. This inter-comparison was performed under various strongly different aerosol loads/types (urban air pollution, biomass burning and Saharan dust event, implementing two different lidar systems (one portable Raymetrics S.A. lidar system running at 355 nm and one multi-wavelength Raman lidar system running at 355 nm, 532 nm and 1064 nm and one CL31 Vaisala S.A. ceilometer (running at 910 nm. Spectral conversions of the ceilometer's data were performed using the Ångström exponent estimated by ultraviolet multi-filter radiometer (UV-MFR measurements. The inter-comparison was based on two parameters: the mixing layer height determined by the presence of the suspended aerosols and the attenuated backscatter coefficient. Additionally, radiosonde data were used to derive the PBL height. In general, a good agreement was found between the ceilometer and the lidar techniques in both inter-compared parameters in the height range from 500 m to 5000 m, while the limitations of each instrument are also examined.

  4. Comparison of ambient aerosol extinction coefficients obtained from in-situ, MAX-DOAS and LIDAR measurements at Cabauw

    Directory of Open Access Journals (Sweden)

    P. Zieger

    2011-03-01

    Full Text Available In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30–40%. Since ambient aerosol particles experience hygroscopic growth at enhanced RH, their microphysical and optical properties – especially the aerosol light scattering – are also strongly dependent on RH. The knowledge of this RH effect is of crucial importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. Here, we will present results from a four-month campaign which took place in summer 2009 in Cabauw, The Netherlands. The aerosol scattering coefficient σsp(λ was measured dry and at various, predefined RH conditions between 20 and 95% with a humidified nephelometer. The scattering enhancement factor f(RH,λ is the key parameter to describe the effect of RH on σsp(λ and is defined as σsp(RH,λ measured at a certain RH divided by the dry σsp(dry,λ. The measurement of f(RH,λ together with the dry absorption measurement (assumed not to change with RH allows the determination of the actual extinction coefficient σep(RH,λ at ambient RH. In addition, a wide range of other aerosol properties were measured in parallel. The measurements were used to characterize the effects of RH on the aerosol optical properties. A closure study showed the consistency of the aerosol in-situ measurements. Due to the large variability of air mass origin (and thus aerosol composition a simple parameterization of f(RH,λ could not be established. If f(RH,λ needs to be predicted, the chemical composition and size distribution need to be known. Measurements of four MAX-DOAS (multi-axis differential optical absorption spectroscopy instruments were used to retrieve vertical profiles of σep(λ. The values of the lowest layer were compared to the in-situ values after conversion of the latter ones to ambient

  5. Atmospheric aerosol in an urban area: Comparison of measurement instruments and methodologies and pulmonary deposition assessment

    International Nuclear Information System (INIS)

    Berico, M.; Luciani, A.; Formignani, M.

    1996-07-01

    In March 1995 a measurement campaign of atmospheric aerosol in the Bologna urban area (Italy) was carried out. A transportable laboratory, set up by ENEA (Italian national Agency for New Technologies, Energy and the Environment) Environmental Department (Bologna), was utilized with instruments for measurement of atmospheric aerosol and meteorological parameters. The aim of this campaign was of dual purpose: to characterize aerosol in urban area and to compare different instruments and methodologies of measurements. Mass concentrations measurements, evaluated on a 23-hour period with total filter, PM10 dichotomous sampler and low pressure impactor (LPI Berner), have provided information respectively about total suspended particles, respirable fraction and granulometric parameters of aerosol. Eight meteorologic parameters, number concentration of submicromic fraction of aerosol and mass concentration of micromic fraction have been continually measured. Then, in a daytime period, several number granulometries of atmospheric aerosol have also been estimated by means of diffusion battery system. Results related to different measurement methodologies and granulometric characteristics of aerosol are presented here. Pulmonary deposition of atmospheric aerosol is finally calculated, using granulometries provided by LPI Brener and ICRP 66 human respiratory tract model

  6. An In Vitro Aerosolization Efficiency Comparison of Generic and Branded Salbutamol Metered Dose Inhalers

    Directory of Open Access Journals (Sweden)

    Sara Rahimkhani, Saeed Ghanbarzadeh, Ali Nokhodchi, Hamed Hamishehkar

    2017-03-01

    Full Text Available Background: Due to the high rate of pulmonary diseases, respiratory drug delivery systems have been attracted excessive attention for the past decades. Because of limitations and growing drug bill, physicians are encouraged to prescribe generically whenever possible. The purpose of this study was to evaluate whether there was any significant difference in aerosolization performance between a reference brand Salbutamol (A Metered Dose Inhalers (MDIs and two generic products (B and C. Methods: The aerosolization performance of MDIs was evaluated by calculating aerosolization indexes including fine particle fraction (FPF, fine particle dose (FPD, geometric standard deviation (GSD and mass median aerodynamic diameters (MMAD by using the next generation impactor. Results: Although aerosolization indexes of MDI A were superior than the Iranian brands, but the differences were not statistically significant. Conclusion: These results verified that generic MDIs deliver similar quantities of Salbutamol to the reference brand and aerosolization performance parameters of generic Salbutamol MDIs did not differ significantly from the reference brand.

  7. SCIAMACHY WFM-DOAS XCO2: comparison with CarbonTracker XCO2 focusing on aerosols and thin clouds

    Directory of Open Access Journals (Sweden)

    J. P. Burrows

    2012-08-01

    Full Text Available Carbon dioxide (CO2 is the most important greenhouse gas whose atmospheric loading has been significantly increased by anthropogenic activity leading to global warming. Accurate measurements and models are needed in order to reliably predict our future climate. This, however, has challenging requirements. Errors in measurements and models need to be identified and minimised. In this context, we present a comparison between satellite-derived column-averaged dry air mole fractions of CO2, denoted XCO2, retrieved from SCIAMACHY/ENVISAT using the WFM-DOAS (weighting function modified differential optical absorption spectroscopy algorithm, and output from NOAA's global CO2 modelling and assimilation system CarbonTracker. We investigate to what extent differences between these two data sets are influenced by systematic retrieval errors due to aerosols and unaccounted clouds. We analyse seven years of SCIAMACHY WFM-DOAS version 2.1 retrievals (WFMDv2.1 using CarbonTracker version 2010. We investigate to what extent the difference between SCIAMACHY and CarbonTracker XCO2 are temporally and spatially correlated with global aerosol and cloud data sets. For this purpose, we use a global aerosol data set generated within the European GEMS project, which is based on assimilated MODIS satellite data. For clouds, we use a data set derived from CALIOP/CALIPSO. We find significant correlations of the SCIAMACHY minus CarbonTracker XCO2 difference with thin clouds over the Southern Hemisphere. The maximum temporal correlation we find for Darwin, Australia (r2 = 54%. Large temporal correlations with thin clouds are also observed over other regions of the Southern Hemisphere (e.g. 43% for South America and 31% for South Africa. Over the Northern Hemisphere the temporal correlations are typically much lower. An exception is India, where large temporal correlations with clouds and aerosols have also been found. For all other regions the temporal correlations with

  8. Comparison of ferrite materials for pulse applications

    International Nuclear Information System (INIS)

    Dinkel, J.A.; Jensen, C.C.

    1993-06-01

    Materials are the limiting factor in many pulse power projects. The magnetic materials available from several manufacturers were experimentally compared for their usefulness in high speed magnetic field applications. This particular application is a high speed kicker magnet for manipulation of a charged particle beam

  9. Unveiling aerosol-cloud interactions - Part 2: Minimising the effects of aerosol swelling and wet scavenging in ECHAM6-HAM2 for comparison to satellite data

    Science.gov (United States)

    Neubauer, David; Christensen, Matthew W.; Poulsen, Caroline A.; Lohmann, Ulrike

    2017-11-01

    Aerosol-cloud interactions (ACIs) are uncertain and the estimates of the ACI effective radiative forcing (ERFaci) magnitude show a large variability. Within the Aerosol_cci project the susceptibility of cloud properties to changes in aerosol properties is derived from the high-resolution AATSR (Advanced Along-Track Scanning Radiometer) data set using the Cloud-Aerosol Pairing Algorithm (CAPA) (as described in our companion paper) and compared to susceptibilities from the global aerosol climate model ECHAM6-HAM2 and MODIS-CERES (Moderate Resolution Imaging Spectroradiometer - Clouds and the Earth's Radiant Energy System) data. For ECHAM6-HAM2 the dry aerosol is analysed to mimic the effect of CAPA. Furthermore the analysis is done for different environmental regimes. The aerosol-liquid water path relationship in ECHAM6-HAM2 is systematically stronger than in AATSR-CAPA data and cannot be explained by an overestimation of autoconversion when using diagnostic precipitation but rather by aerosol swelling in regions where humidity is high and clouds are present. When aerosol water is removed from the analysis in ECHAM6-HAM2 the strength of the susceptibilities of liquid water path, cloud droplet number concentration and cloud albedo as well as ERFaci agree much better with those of AATSR-CAPA or MODIS-CERES. When comparing satellite-derived to model-derived susceptibilities, this study finds it more appropriate to use dry aerosol in the computation of model susceptibilities. We further find that the statistical relationships inferred from different satellite sensors (AATSR-CAPA vs. MODIS-CERES) as well as from ECHAM6-HAM2 are not always of the same sign for the tested environmental conditions. In particular the susceptibility of the liquid water path is negative in non-raining scenes for MODIS-CERES but positive for AATSR-CAPA and ECHAM6-HAM2. Feedback processes like cloud-top entrainment that are missing or not well represented in the model are therefore not well

  10. A Review on the Study of the Generation of (Nanoparticles Aerosols during the Mechanical Solicitation of Materials

    Directory of Open Access Journals (Sweden)

    Neeraj Shandilya

    2014-01-01

    Full Text Available This paper focuses on presenting the forefront of the interdisciplinary studies conceived towards the generation of the wear particles aerosol when materials are subjected to mechanical stresses. Various wear mechanisms and instrumentation involved during stress application and aerosolization of wear particles, as well as particles characterization, measurement, and modeling techniques are presented through the investigation of a series of contextual works which are emphasized on the identification of these aspects. The review is motivated from the fact that understanding mechanisms involved in wear-induced particle generation, both at nano- and at microscale, is important for many applications that involve surfaces sliding over each other due to various potential health aspects. An attempt has been made to explain how the information based on this broad spectrum of subjects discovered in this contribution can be used and improved in order to produce a more resilient, rational, and versatile knowledge base which has been found lacking in the present literature during its survey. The area of study is highly multidisciplinary since it involves aerosol, particle, and material sciences.

  11. Vertical Profiles of Aerosol Optical Properties Over Central Illinois and Comparison with Surface and Satellite Measurements

    Science.gov (United States)

    Sheridan P. J.; Andrews, E.; Ogren, J A.; Tackett, J. L.; Winker, D. M.

    2012-01-01

    Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1) measure the in situ aerosol properties and determine their vertical and temporal variability and (2) relate these aircraft measurements to concurrent surface and satellite measurements. Underflights of the CALIPSO satellite show reasonable agreement in a majority of retrieved profiles between aircraft-measured extinction at 532 nm (adjusted to ambient relative humidity) and CALIPSO-retrieved extinction, and suggest that routine aircraft profiling programs can be used to better understand and validate satellite retrieval algorithms. CALIPSO tended to overestimate the aerosol extinction at this location in some boundary layer flight segments when scattered or broken clouds were present, which could be related to problems with CALIPSO cloud screening methods. The in situ aircraft-collected aerosol data suggest extinction thresholds for the likelihood of aerosol layers being detected by the CALIOP lidar. These statistical data offer guidance as to the likelihood of CALIPSO's ability to retrieve aerosol extinction at various locations around the globe.

  12. Simulation of aerosol optical properties over a tropical urban site in India using a global model and its comparison with ground measurements

    Directory of Open Access Journals (Sweden)

    D. Goto

    2011-05-01

    Full Text Available Aerosols have great impacts on atmospheric environment, human health, and earth's climate. Therefore, information on their spatial and temporal distribution is of paramount importance. Despite numerous studies have examined the variation and trends of BC and AOD over India, only very few have focused on their spatial distribution or even correlating the observations with model simulations. In the present study, a three-dimensional aerosol transport-radiation model coupled with a general circulation model. SPRINTARS, simulated atmospheric aerosol distributions including BC and aerosol optical properties, i.e., aerosol optical thickness (AOT, Ångström Exponent (AE, and single scattering albedo (SSA. The simulated results are compared with both BC measurements by aethalometer and aerosol optical properties measured by ground-based skyradiometer and by satellite sensor, MODIS/Terra over Hyderabad, which is a tropical urban area of India, for the year 2008. The simulated AOT and AE in Hyderabad are found to be comparable to ground-based measured ones. The simulated SSA tends to be higher than the ground-based measurements. Both these comparisons of aerosol optical properties between the simulations with different emission inventories and the measurements indicate that, firstly the model uncertainties derived from aerosol emission inventory cannot explain the gaps between the simulations and the measurements and secondly the vertical transport of BC and the treatment of BC-containing particles can be the main issue in the global model to solve the gap.

  13. An inter-laboratory comparison of Si isotope reference materials

    NARCIS (Netherlands)

    Reynolds, B.C.; Aggarwal, J.; André, L.; Baxter, B.; Beucher, C.; Brzezinski, M.A.; Engström, E.; Georg, R.B.; Land, M.; Leng, M.J.; Opfergelt, S.; Rodushkin, I.; Sloane, H.J.; Van den Boorn, S.H.J.M.; Vroon, P.Z.; Cardinal, D.

    2007-01-01

    Three Si isotope materials have been used for an inter-laboratory comparison exercise to ensure reproducibility between international laboratories investigating natural Si isotope variations using a variety of chemical preparation methods and mass spectrometric techniques. These proposed standard

  14. Optical Properties of Biomass Burning Aerosols: Comparison of Experimental Measurements and T-Matrix Calculations

    Directory of Open Access Journals (Sweden)

    Samin Poudel

    2017-11-01

    Full Text Available The refractive index (RI is an important parameter in describing the radiative impacts of aerosols. It is important to constrain the RI of aerosol components, since there is still significant uncertainty regarding the RI of biomass burning aerosols. Experimentally measured extinction cross-sections, scattering cross-sections, and single scattering albedos for white pine biomass burning (BB aerosols under two different burning and sampling conditions were modeled using T-matrix theory. The refractive indices were extracted from these calculations. Experimental measurements were conducted using a cavity ring-down spectrometer to measure the extinction, and a nephelometer to measure the scattering of size-selected aerosols. BB aerosols were obtained by burning white pine using (1 an open fire in a burn drum, where the aerosols were collected in distilled water using an impinger, and then re-aerosolized after several days, and (2 a tube furnace to directly introduce the BB aerosols into an indoor smog chamber, where BB aerosols were then sampled directly. In both cases, filter samples were also collected, and electron microscopy images were used to obtain the morphology and size information used in the T-matrix calculations. The effective radius of the particles collected on filter media from the open fire was approximately 245 nm, whereas it was approximately 76 nm for particles from the tube furnace burns. For samples collected in distilled water, the real part of the RI increased with increasing particle size, and the imaginary part decreased. The imaginary part of the RI was also significantly larger than the reported values for fresh BB aerosol samples. For the particles generated in the tube furnace, the real part of the RI decreased with particle size, and the imaginary part was much smaller and nearly constant. The RI is sensitive to particle size and sampling method, but there was no wavelength dependence over the range considered (500

  15. Comparison of european computer codes relative to the aerosol behavior in PWR containment buildings during severe core damage accidents. (Modelling of steam condensation on the particles)

    International Nuclear Information System (INIS)

    Bunz, H.; Dunbar, L.H.; Fermandjian, J.; Lhiaubet, G.

    1987-11-01

    An aerosol code comparison exercise was performed within the framework of the Commission of European Communities (Division of Safety of Nuclear Installations). This exercise, focused on the process of steam condensation onto the aerosols occurring in PWR containment buildings during severe core damage accidents, has allowed to understand the discrepancies between the results obtained. These discrepancies are due, in particular, to whether the curvature effect is modelled or not in the codes

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  17. Tobacco-Specific Nitrosamines in Electronic Cigarettes: Comparison between Liquid and Aerosol Levels

    Directory of Open Access Journals (Sweden)

    Konstantinos E. Farsalinos

    2015-07-01

    Full Text Available Introduction: Although electronic cigarette (EC liquids contain low levels of tobacco-specific nitrosamines (TSNAs, studies evaluating the levels emitted to the aerosol are scarce. The purpose of this study was to compare the levels of TSNAs between liquids and generated aerosol. Methods: Three EC liquids were obtained from the market. An additional (spiked sample was prepared by adding known amounts of standard TSNAs solutions to one of the obtained liquids. N-nitrosonornicotine (NNN, N-nitrosoanatabine (NAT, N-nitrosoanabasine (NAB and 4-(methylnitrosamino1-(3-pyridyl-1-butanone (NNK were measured. Three 100-puff sets from each liquid were trapped in filter pads and were subsequently analyzed for the presence of TSNAs. The expected levels of TSNAs (calculated based on the liquid consumption were compared with the measured levels in the aerosol. Results: Only NAB was found at trace levels in two commercial liquids (1.2 and 2.3 ng/g, while the third contained 1.5 ng/g NAB and 7.7 ng/g NNN. The 100-puff sets resulted in 336–515 mg liquid consumption, with no TSNAs being detected in the aerosol. The spiked sample contained 42.0–53.9 ng/g of each of the TSNAs. All TSNAs were detected in the aerosol with the measured levels being statistically similar to the expected amounts. A significant correlation between expected and measured levels of TSNAs in the aerosol was found (r = 0.83, p < 0.001. Conclusion: The findings of this study show that exposure of EC users to TSNAs can be accurately assessed based on the levels present in the liquid, without the need to analyze the aerosol.

  18. Comparison of the impact of volcanic eruptions and aircraft emissions on the aerosol mass loading and sulfur budget in the stratosphere

    Science.gov (United States)

    Yue, Glenn K.; Poole, Lamont R.

    1992-01-01

    Data obtained by the Stratospheric Aerosol and Gas Experiment (SAGE) 1 and 2 were used to study the temporal variation of aerosol optical properties and to assess the mass loading of stratospheric aerosols from the eruption of volcanos Ruiz and Kelut. It was found that the yearly global average of optical depth at 1.0 micron for stratospheric background aerosols in 1979 was 1.16 x 10(exp -3) and in 1989 was 1.66 x 10(exp -3). The eruptions of volcanos Ruiz and Kelut ejected at least 5.6 x 10(exp 5) and 1.8 x 10(exp 5) tons of materials into the stratosphere, respectively. The amount of sulfur emitted per year from the projected subsonic and supersonic fleet is comparable to that contained in the background aerosol particles in midlatitudes from 35 deg N to 55 deg N.

  19. Maritime Aerosol Network optical depth measurements and comparison with satellite retrievals from various different sensors

    Science.gov (United States)

    Smirnov, Alexander; Petrenko, Maksym; Ichoku, Charles; Holben, Brent N.

    2017-10-01

    The paper reports on the current status of the Maritime Aerosol Network (MAN) which is a component of the Aerosol Robotic Network (AERONET). A public domain web-based data archive dedicated to MAN activity can be found at https://aeronet.gsfc.nasa.gov/new_web/maritime_aerosol_network.html . Since 2006 over 450 cruises were completed and the data archive consists of more than 6000 measurement days. In this work, we present MAN observations collocated with MODIS Terra, MODIS Aqua, MISR, POLDER, SeaWIFS, OMI, and CALIOP spaceborne aerosol products using a modified version of the Multi-Sensor Aerosol Products Sampling System (MAPSS) framework. Because of different spatio-temporal characteristics of the analyzed products, the number of MAN data points collocated with spaceborne retrievals varied between 1500 matchups for MODIS to 39 for CALIOP (as of August 2016). Despite these unavoidable sampling biases, latitudinal dependencies of AOD differences for all satellite sensors, except for SeaWIFS and POLDER, showed positive biases against ground truth (i.e. MAN) in the southern latitudes (<50° S), and substantial scatter in the Northern Atlantic "dust belt" (5°-15° N). Our analysis did not intend to determine whether satellite retrievals are within claimed uncertainty boundaries, but rather show where bias exists and corrections are needed.

  20. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2013-07-15

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and {sup 131}I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical

  1. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J.

    2013-07-01

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and 131 I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical speciation of

  2. Intersampler field comparison of Respicon(R), IOM, and closed-face 25-mm personal aerosol samplers during primary production of aluminium.

    Science.gov (United States)

    Skaugset, Nils Petter; Ellingsen, Dag G; Notø, Hilde; Jordbekken, Lars; Thomassen, Yngvar

    2013-10-01

    Intersampler field comparison of Respicon(®), 25-mm closed-face 'total dust' cassette (CFC), and IOM inhalable aerosol sampler was conducted in pot rooms at seven aluminium smelters. The aerosol mass and water-soluble fluoride were selected as airborne contaminants for the comparisons. The aerosol masses of 889 sample pairs of IOM and Respicon(®) inhalable aerosol sub-fraction, 165 of IOM and 25-mm CFC, and 194 of CFC and Respicon(®) thoracic aerosol sub-fraction were compared. The number of sample pairs for the comparison of water-soluble fluoride was 906, 170, and 195, respectively. The geometric mean aerosol mass collected with the inhalable Respicon(®) was 2.91 mg m(-3) compared with 3.38 mg m(-3) with the IOM. The overall ratio between IOM and Respicon(®) inhalable sub-fraction was 1.16 [95% confidence interval (CI) = 1.11-1.21] for aerosol mass and 1.13 (95% CI = 1.08-1.18) for water-soluble fluoride. The results indicate that Respicon(®) undersampled the aerosol mass and water-soluble fluoride in the inhalable sub-fraction compared with the IOM. The results indicated undersampling of the Respicon(®) at mass concentrations higher than 1.35 mg m(-3) and oversampling at lower mass concentrations. The overall ratio between aerosol mass collected with IOM and CFC was 4.19 (95% CI = 3.79-4.64) and 1.61 (95% CI = 1.51-1.72) for water-soluble fluoride. Thus, for this industry, a correction factor of 4.2 is suggested for the conversion of CFC to inhalable aerosol masses and a conversion factor of 1.6 for water-soluble fluoride if wall deposits in the CFC are included. CFC and thoracic Respicon(®) collected similar aerosol masses (ratio = 1.04; 95% CI = 0.97-1.12), whereas the ratio was 1.19 (95% CI = 1.11-1.28) for water-soluble fluoride. The variability of the exposure is substantial; thus, large data sets are required in sampler performance field comparisons.

  3. Global combustion sources of organic aerosols: model comparison with 84 AMS factor-analysis data sets

    Science.gov (United States)

    Tsimpidi, Alexandra P.; Karydis, Vlassis A.; Pandis, Spyros N.; Lelieveld, Jos

    2016-07-01

    Emissions of organic compounds from biomass, biofuel, and fossil fuel combustion strongly influence the global atmospheric aerosol load. Some of the organics are directly released as primary organic aerosol (POA). Most are emitted in the gas phase and undergo chemical transformations (i.e., oxidation by hydroxyl radical) and form secondary organic aerosol (SOA). In this work we use the global chemistry climate model ECHAM/MESSy Atmospheric Chemistry (EMAC) with a computationally efficient module for the description of organic aerosol (OA) composition and evolution in the atmosphere (ORACLE). The tropospheric burden of open biomass and anthropogenic (fossil and biofuel) combustion particles is estimated to be 0.59 and 0.63 Tg, respectively, accounting for about 30 and 32 % of the total tropospheric OA load. About 30 % of the open biomass burning and 10 % of the anthropogenic combustion aerosols originate from direct particle emissions, whereas the rest is formed in the atmosphere. A comprehensive data set of aerosol mass spectrometer (AMS) measurements along with factor-analysis results from 84 field campaigns across the Northern Hemisphere are used to evaluate the model results. Both the AMS observations and the model results suggest that over urban areas both POA (25-40 %) and SOA (60-75 %) contribute substantially to the overall OA mass, whereas further downwind and in rural areas the POA concentrations decrease substantially and SOA dominates (80-85 %). EMAC does a reasonable job in reproducing POA and SOA levels during most of the year. However, it tends to underpredict POA and SOA concentrations during winter indicating that the model misses wintertime sources of OA (e.g., residential biofuel use) and SOA formation pathways (e.g., multiphase oxidation).

  4. Combining real-time PCR and next-generation DNA sequencing to provide quantitative comparisons of fungal aerosol populations

    Science.gov (United States)

    Dannemiller, Karen C.; Lang-Yona, Naama; Yamamoto, Naomichi; Rudich, Yinon; Peccia, Jordan

    2014-02-01

    We examined fungal communities associated with the PM10 mass of Rehovot, Israel outdoor air samples collected in the spring and fall seasons. Fungal communities were described by 454 pyrosequencing of the internal transcribed spacer (ITS) region of the fungal ribosomal RNA encoding gene. To allow for a more quantitative comparison of fungal exposure in humans, the relative abundance values of specific taxa were transformed to absolute concentrations through multiplying these values by the sample's total fungal spore concentration (derived from universal fungal qPCR). Next, the sequencing-based absolute concentrations for Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, and Penicillium/Aspergillus spp. were compared to taxon-specific qPCR concentrations for A. alternata, C. cladosporioides, E. nigrum, and Penicillium/Aspergillus spp. derived from the same spring and fall aerosol samples. Results of these comparisons showed that the absolute concentration values generated from pyrosequencing were strongly associated with the concentration values derived from taxon-specific qPCR (for all four species, p 0.70). The correlation coefficients were greater for species present in higher concentrations. Our microbial aerosol population analyses demonstrated that fungal diversity (number of fungal operational taxonomic units) was higher in the spring compared to the fall (p = 0.02), and principal coordinate analysis showed distinct seasonal differences in taxa distribution (ANOSIM p = 0.004). Among genera containing allergenic and/or pathogenic species, the absolute concentrations of Alternaria, Aspergillus, Fusarium, and Cladosporium were greater in the fall, while Cryptococcus, Penicillium, and Ulocladium concentrations were greater in the spring. The transformation of pyrosequencing fungal population relative abundance data to absolute concentrations can improve next-generation DNA sequencing-based quantitative aerosol exposure assessment.

  5. Physicochemical properties of aerosol released in the case of a fire involving materials used in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Ouf, F.-X., E-mail: francois-xavier.ouf@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA/LPMA, PSN-RES/SCA/LECEV, Gif-Sur-Yvette 91192 (France); Mocho, V.-M.; Pontreau, S.; Wang, Z. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA/LPMA, PSN-RES/SCA/LECEV, Gif-Sur-Yvette 91192 (France); Ferry, D. [Aix-Marseille Université, CNRS UMR 7325, CINaM, 13009 Marseille (France); Yon, J. [CORIA-UMR 6614-Normandie Université, CNRS-Université et Insa de Rouen, Campus Universitaire du Madrillet, 76800 Saint-Etienne-du-Rouvray (France)

    2015-02-11

    Graphical abstract: - Highlights: • We characterize the aerosol emitted during thermal degradation of common materials. • Oxygen concentration on aerosol properties has been investigated. • Influence of oxygen concentration is limited to the organic carbon fraction. • The organic carbon fraction is correlated to the C:H ratio. • For pure materials, monomer diameter is correlated to the emission factor. - Abstract: For industrial concerns, and more especially for nuclear applications, the characterization of soot is essential for predicting the behaviour of containment barriers in fire conditions. This study deals with the characterization (emission factor, composition, size, morphology, microstructure) of particles produced during thermal degradation of materials found in nuclear facilities (electrical cables, polymers, oil and solvents). Small-scale experiments have been conducted for oxygen concentrations [O{sub 2}] ranging from 15% to 21% in order to imitate the oxygen depletion encountered during a confined fire. Particles denote distinct shapes, from aggregates composed of monomers with diameters ranging from 31.2 nm to 52.8 nm, to compact nanoparticles with diameters ranging from 15 nm to 400 nm, and their composition strongly depends on fuel type. Despite the organic to total carbon ratio (OC/TC), their properties are poorly influenced by the decrease in [O{sub 2}]. Finally, two empirical correlations are proposed for predicting the OC/TC ratio and the monomer diameter, respectively, as a function of the fuel's carbon to hydrogen ratio and the emission factor.

  6. Comparison of aerosol and cloud condensation nuclei between wet and dry seasons in Guangzhou, southern China.

    Science.gov (United States)

    Duan, Junyan; Tao, Jun; Wu, Yunfei; Cheng, Tiantao; Zhang, Renjian; Wang, Yanyu; Zhu, Hailin; Xie, Xin; Liu, Yuehui; Li, Xiang; Kong, Lingdong; Li, Mei; He, Qianshan

    2017-12-31

    Cloud condensation nuclei (CCN), condensation nuclei (CN) and aerosol chemical composition were measured simultaneously at an urban site of Guangzhou from July to August 2015 and in January 2016, and the seasonal variations of aerosol activated fractions (N CCN /N CN ) as well as their relevant influence factors were further studied accordingly. N CN is generally higher in winter (dry season), whereas N CCN and N CCN /N CN are mostly higher in summer (wet season) instead. In particular, N CCN and N CCN /N CN are much lower at smaller supersaturation levels (SStransportation, meteorological conditions, etc., also contribute to the variations of N CCN and N CCN /N CN. Particles from the local source or local-oceanic combination source cast influence on CN and CCN significantly, while the pollutants originating from and crossing over distant polluted areas contribute largely to CCN/CN. N CN and N CCN are relatively higher under pollution-free conditions in summertime and polluted conditions in wintertime, but N CCN /N CN is just the opposite. On various polluted conditions, aerosol CCN activities are greatly discrepant between summer and winter, especially during mist or heavy haze periods. The results imply that anthropogenic pollutants exert critical impacts on aerosol CCN activation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Modeling of aerosol formation during biomass combustion in grate furnaces and comparison with measurements

    NARCIS (Netherlands)

    Joeller, M.; Brunner, T.; Obernberger, I.

    2005-01-01

    Results from mathematical modeling of aerosol formation during combustion of woody biomass fuels were compared with results from particle size distribution (PSD) measurements at a pilot-scale biomass combustion unit with moving grate and flame tube boiler. The mathematical model is a plug flow model

  8. Comparison of high order algorithms in Aerosol and Aghora for compressible flows

    Directory of Open Access Journals (Sweden)

    Mbengoue D. A.

    2013-12-01

    Full Text Available This article summarizes the work done within the Colargol project during CEMRACS 2012. The aim of this project is to compare the implementations of high order finite element methods for compressible flows that have been developed at ONERA and at INRIA for about one year, within the Aghora and Aerosol libraries.

  9. Atmospheric aerosol in an urban area: Comparison of measurement instruments and methodologies and pulmonary deposition assessment; Aerosol atmosferico in area urbanae di misura e valutazione di deposizione polmonare

    Energy Technology Data Exchange (ETDEWEB)

    Berico, M; Luciani, A; Formignani, M [ENEA, Centro Ricerche Bologna (Italy). Dip. Ambiente

    1996-07-01

    In March 1995 a measurement campaign of atmospheric aerosol in the Bologna urban area (Italy) was carried out. A transportable laboratory, set up by ENEA (Italian national Agency for New Technologies, Energy and the Environment) Environmental Department (Bologna), was utilized with instruments for measurement of atmospheric aerosol and meteorological parameters. The aim of this campaign was of dual purpose: to characterize aerosol in urban area and to compare different instruments and methodologies of measurements. Mass concentrations measurements, evaluated on a 23-hour period with total filter, PM10 dichotomous sampler and low pressure impactor (LPI Berner), have provided information respectively about total suspended particles, respirable fraction and granulometric parameters of aerosol. Eight meteorologic parameters, number concentration of submicromic fraction of aerosol and mass concentration of micromic fraction have been continually measured. Then, in a daytime period, several number granulometries of atmospheric aerosol have also been estimated by means of diffusion battery system. Results related to different measurement methodologies and granulometric characteristics of aerosol are presented here. Pulmonary deposition of atmospheric aerosol is finally calculated, using granulometries provided by LPI Brener and ICRP 66 human respiratory tract model.

  10. Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2013-05-01

    Full Text Available Primary marine aerosols (PMAs are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent, will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw range between −1°C and 15°C. A sharp decrease in PMA emissions for a Tw increase from −1°C to 4°C was followed by a lower rate of change in PMA emissions for Tw up to about 6°C. Near constant number concentrations for water temperatures between 6°C to 10°C and higher were recorded. Even though the total particle number concentration changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for a dry diameter (DpDp > 0.125μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%. The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1°C to 10°C during winter measurements showed a decrease in the peak of relative particle number concentration at about a Dp of 0.180μm, while an increase was observed for particles with Dp > 1μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range

  11. Comparison of Debrecen fine fraction aerosol data with others collected in some European collaboration

    International Nuclear Information System (INIS)

    Koltay, E.; Borbely-Kiss, I.; Dobos, E.; Kertesz, Zs.; Szabo, Gy.

    2006-01-01

    Complete text of publication follows. Recently a number of papers have been published by European groups [1], [2], [3], [4] organized mainly by western- and middle European laboratories, in which comparative data have been presented from co-ordinated research programs for air qualification in a number of urban sites based on joint evaluation of elemental composition and reflectance of ambient fine aerosol particles. The time interval June 2000 to December 2001 scanned in the co-ordinated program of Goetchi et al [1] is mainly covered by a part of our long term data set. All together 107 sampling days have been used here work over the above time interval. Due to the gross parallelism of the total observation periods and the principal similarity of the used analytical methods in their and our works, we found it plausible to find out how much the air quality characteristics observed at our location fit in the general European trends. Sampling sites arranged in selected European regions are numbered as follows: West and Central Europe: Antwerp South (1), Antwerp City (2), Paris (3), Erfurt (4), Basel (5); Spain: Barcelona (6), Galdakao (7), Albacete (8), Oviedo (9), Huelva (10); Alpine France: Grenoble (11); Northern Italy: Pavia (12), Turin (13), Verona (14); England: Ipswitch (15), Norwich (16); Scandinavia: Reykjavik (17), Gothenburg (18), Umea (19), Uppsala (20); Estonia: Tartu (21); Hungary: Debrecen (22). For a first orientation about the existence of similarities and differences within and among the regional features, respectively, yearly average concentrations are presented in Figure 1 for silicon, and sulphur elemental constituents and PM2,5 integral concentrations for sites 1 22. Silicon, sulphur, and black carbon are considered as main representatives of the crustal material, traffic and long-range background pollution components, respectively, while PM2.5 is a parameter accepted for measuring overall air quality from the point of view of human health

  12. Measurement and characterization of filtration efficiencies for prefilter materials used in aerosol filtration

    International Nuclear Information System (INIS)

    Sciortino, J.

    1991-01-01

    In applications where the filtration of large quantities of mixed (liquid and solid) aerosols is desired, a multistage filtration system is often employed. This system consists of a prefilter, a High Efficiency Particulate Air (HEPA) filter, and any number of specialized filters particular to the filtration application. The prefilter removes liquids and any large particles from the air stream, keeping them from prematurely loading the HEPA filter downstream. The HEPA filter eliminates 99.97% of all particulates in the aerosol. The specialized filters downstream of the HEPA filter can be used to remove organic volatiles or other vapors. While the properties of HEPA filters have been extensively investigated, literature characterizing the prefilter is scarce. The purpose of this report is to characterize the efficiency of the prefilter as a function of particle size, nature of the particle (solid or liquid), and the gas flow rate across the face of the prefilter. 1 ref., 4 figs

  13. EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    V. V. Kuzin

    2018-01-01

    Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

  14. Comparison of different methods used in integral codes to model coagulation of aerosols

    Science.gov (United States)

    Beketov, A. I.; Sorokin, A. A.; Alipchenkov, V. M.; Mosunova, N. A.

    2013-09-01

    The methods for calculating coagulation of particles in the carrying phase that are used in the integral codes SOCRAT, ASTEC, and MELCOR, as well as the Hounslow and Jacobson methods used to model aerosol processes in the chemical industry and in atmospheric investigations are compared on test problems and against experimental results in terms of their effectiveness and accuracy. It is shown that all methods are characterized by a significant error in modeling the distribution function for micrometer particles if calculations are performed using rather "coarse" spectra of particle sizes, namely, when the ratio of the volumes of particles from neighboring fractions is equal to or greater than two. With reference to the problems considered, the Hounslow method and the method applied in the aerosol module used in the ASTEC code are the most efficient ones for carrying out calculations.

  15. The comparison of MODIS-Aqua (C5 and CALIOP (V2 & V3 aerosol optical depth

    Directory of Open Access Journals (Sweden)

    J. Redemann

    2012-03-01

    Full Text Available We assess the consistency between instantaneously collocated level-2 aerosol optical depth (AOD retrievals from MODIS-Aqua (C5 and CALIOP (Version 2 & 3, comparing the standard MODIS AOD (MYD04_L2 data to the AOD calculated from CALIOP aerosol extinction profiles for both the previous release (V2 and the latest release (V3 of CALIOP data. Based on data collected in January 2007, we investigate the most useful criteria for screening the MODIS and CALIOP retrievals to achieve the best agreement between the two data sets. Applying these criteria to eight months of data (Jan, Apr, Jul, Oct 2007 and 2009, we find an order of magnitude increase for the CALIOP V3 data density (by comparison to V2, that is generally accompanied by equal or better agreement with MODIS AOD. Differences in global, monthly mean, over-ocean AOD (532 nm between CALIOP and MODIS range between 0.03 and 0.04 for CALIOP V3, with CALIOP generally biased low, when all available data from both sensors are considered. Root-mean-squares (RMS differences in instantaneously collocated AOD retrievals by the two instruments are reduced from values ranging between 0.14 and 0.19 using the unscreened V3 data to values ranging from 0.09 to 0.1 for the screened data. A restriction to scenes with cloud fractions less than 1% (as defined in the MODIS aerosol retrievals generally results in improved correlation (R2>0.5, except for the month of July when correlations remain relatively lower. Regional assessments show hot spots in disagreement between the two sensors in Asian outflow during April and off the coast of South Africa in July.

  16. A study of the comparison between human and animal excretion data following inhalation exposure to plutonium 238 oxide aerosols

    International Nuclear Information System (INIS)

    Moss, W.D.; Martinez, G.; Gautier, M.A.

    1985-01-01

    Bioassay urine samples obtained since 1971 from eight Los Alamos employees, accidentally exposed by inhalation to high-fired plutonium-238 oxide aerosols, were studied and compared with excretion data obtained from Beagle dogs exposed to /sup 238/PuO/sub 2/ aerosols. The early period Pu human excretion data from the inhalation exposure were unexpected and were unlike previously studied occupational exposure urinary data obtained at Los Alamos. The initial urine samples collected on day one were below the detection limits of the analytical method (0.01 pCi). Within thirty days, however, detectible concentrations of Pu were measured in the urine for several of the exposed personnel. The amounts of Pu excreted continued to increase in each of the cases throughout the first year and the individual patterns of Pu excretion were similar. The human urinary excretion data was compared with similar excretion data obtained from an animal study conducted by the Inhalation Toxicology Research Institute (Me81). In the animal study, Beagle dogs received inhalation exposure to one of three sizes of monodisperse of polydisperse aerosol of /sup 238/PuO/sub 2/. Periodic sacrifice of pairs of dogs during the 4 years after the inhalation exposure provided data on the retention, translocation and mode of excretion of /sup 238/Pu. The comparison of human and animal /sup 238/Pu excretion data supported the observation that the excretion data were similar between the two species and that the animal excretion models can be applied to predict the human /sup 238/Pu excretion following inhalation exposure to high-fired oxides of /sup 238/Pu

  17. Model simulations of aerosol effects on clouds and precipitation in comparison with ARM data

    Energy Technology Data Exchange (ETDEWEB)

    Penner, Joyce E. [Univ. of Michigan, Ann Arbor, MI (United States); Zhou, Cheng [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-01-12

    Observation-based studies have shown that the aerosol cloud lifetime effect or the increase of cloud liquid water path (LWP) with increased aerosol loading may have been overestimated in climate models. Here, we simulate shallow warm clouds on 05/27/2011 at the Southern Great Plains (SGP) measurement site established by Department of Energy's Atmospheric Radiation Measurement (ARM) Program using a single column version of a global climate model (Community Atmosphere Model or CAM) and a cloud resolving model (CRM). The LWP simulated by CAM increases substantially with aerosol loading while that in the CRM does not. The increase of LWP in CAM is caused by a large decrease of the autoconversion rate when cloud droplet number increases. In the CRM, the autoconversion rate is also reduced, but this is offset or even outweighed by the increased evaporation of cloud droplets near cloud top, resulting in an overall decrease in LWP. Our results suggest that climate models need to include the dependence of cloud top growth and the evaporation/condensation process on cloud droplet number concentrations.

  18. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    uncertainties by "the I-beams". Only an uncertainty range rather than a best estimate is presented for direct aerosol forcing by mineral dust and for indirect aerosol forcing. An assessment of the present level of scientific understanding is indicated at the bottom of the figure (reproduced by permission of Intergovernmental Panel on Climate Change). The importance of atmospheric aerosols to issues of societal concern has motivated much research intended to describe their loading, distribution, and properties and to develop understanding of the controlling processes to address such issues as air pollution, acid deposition, and climate influences of aerosols. However, description based wholly on measurements will inevitably be limited in its spatial and temporal coverage and in the limited characterization of aerosol properties. These limitations are even more serious for predictions of future emissions and provide motivation for concurrent theoretical studies and development of model-based description of atmospheric aerosols.An important long-range goal, which has already been partly realized, is to develop quantitative understanding of the processes that control aerosol loading, composition, and microphysical properties as well as the resultant optical and cloud-nucleating properties. An objective is to incorporate these results into chemical transport models that can be used for predictions. Such models are required, for example, to design approaches to achieve air quality standards and to assess and predict aerosol influences on climate change. Much current research is directed toward enhancing this understanding and to evaluating it by comparison of model results and observations. However, compared to gases, models involving particles are far more complex because of the need to specify additional parameters such as particle sizes and size distributions, compositions as a function of size, particle shapes, and temporal and spatial variations, including reactions that occur

  19. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS

    Science.gov (United States)

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS.Chong S. Kim, SC. Hu*, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, ...

  20. The aerosol distribution in Europe derived with the Community Multiscale Air Quality (CMAQ model: comparison to near surface in situ and sunphotometer measurements

    Directory of Open Access Journals (Sweden)

    V. Matthias

    2008-09-01

    Full Text Available The aerosol distribution in Europe was simulated with the Community Multiscale Air Quality (CMAQ model system version 4.5 for the years 2000 and 2001. The results were compared with daily averages of PM10 measurements taken in the framework of EMEP and with aerosol optical depth (AOD values measured within AERONET. The modelled total aerosol mass is typically about 30–60% lower than the corresponding measurements. However a comparison of the chemical composition of the aerosol revealed a considerably better agreement between the modelled and the measured aerosol components for ammonium, nitrate and sulfate, which are on average only 15–20% underestimated. Sligthly worse agreement was determined for sea salt, that was only avaliable at two sites. The largest discrepancies result from the aerosol mass which was not chemically specified by the measurements. The agreement between measurements and model is better in winter than in summer. The modelled organic aerosol mass is higher in summer than in winter but it is significantly underestimated by the model. This could be one of the main reasons for the discrepancies between measurements and model results. The other is that primary coarse particles are underestimated in the emissions. The probability distribution function of the PM10 measurements follows a log-normal distribution at most sites. The model is only able to reproduce this distribution function at non-coastal low altitude stations. The AOD derived from the model results is 20–70% lower than the values observed within AERONET. This is mainly attributed to the missing aerosol mass in the model. The day-to-day variability of the AOD and the log-normal distribution functions are quite well reproduced by the model. The seasonality on the other hand is underestimated by the model results because better agreement is achieved in winter.

  1. Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City: Comparison with Las Vegas, Nevada, USA

    Science.gov (United States)

    Arnott, W. P.; Miranda, G. P.; Gaffney, J. S.; Marley, N. A.

    2007-05-01

    Four photoacoustic spectrometers (PAS) for aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The four sites included: an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP); a suburban site at the Technological University of Tecamac; a rural site at "La Biznaga" ranch; and a site at the Paseo de Cortes (altitude 3,810 meters ASL) in the rural area above Amecameca in the State of Mexico, on the saddle between the volcanoes Popocatepetl and Iztaccihuatl. A similar campaign was held in Las Vegas, Nevada, USA in January-February, 2003. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions while the other sites provided characterization of the plume, mixed in with any local sources. The second and third sites are north of Mexico City, and the fourth site is south. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Instruments at the second and third sites operate at 870 nm, and the one at the fourth site at 780 nm. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. Comparisons with TSI nephelometer scattering at the T0 site will be presented. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of

  2. A Comparison of Seasonal and Interannual Variability of Soil Dust Aerosols Over the Atlantic Ocean as Inferred by the Toms AI and AVHRR AOT Retrievals

    Science.gov (United States)

    Cakmur, R. V.; Miller, R. L.; Tegen, Ina; Hansen, James E. (Technical Monitor)

    2001-01-01

    The seasonal cycle and interannual variability of two estimates of soil (or 'mineral') dust aerosols are compared: Advanced Very High Resolution Radiometer (AVHRR) aerosol optical thickness (AOT) and Total Ozone Mapping Spectrometer (TOMS) aerosol index (AI), Both data sets, comprising more than a decade of global, daily images, are commonly used to evaluate aerosol transport models. The present comparison is based upon monthly averages, constructed from daily images of each data set for the period between 1984 and 1990, a period that excludes contamination from volcanic eruptions. The comparison focuses upon the Northern Hemisphere subtropical Atlantic Ocean, where soil dust aerosols make the largest contribution to the aerosol load, and are assumed to dominate the variability of each data set. While each retrieval is sensitive to a different aerosol radiative property - absorption for the TOMS AI versus reflectance for the AVHRR AOT - the seasonal cycles of dust loading implied by each retrieval are consistent, if seasonal variations in the height of the aerosol layer are taken into account when interpreting the TOMS AI. On interannual time scales, the correlation is low at most locations. It is suggested that the poor interannual correlation is at least partly a consequence of data availability. When the monthly averages are constructed using only days common to both data sets, the correlation is substantially increased: this consistency suggests that both TOMS and AVHRR accurately measure the aerosol load in any given scene. However, the two retrievals have only a few days in common per month so that these restricted monthly averages have a large uncertainty. Calculations suggest that at least 7 to 10 daily images are needed to estimate reliably the average dust load during any particular month, a threshold that is rarely satisfied by the AVHRR AOT due to the presence of clouds in the domain. By rebinning each data set onto a coarser grid, the availability of

  3. Aerosol assisted synthesis of hierarchical tin–carbon composites and their application as lithium battery anode materials

    KAUST Repository

    Guo, Juchen

    2013-01-01

    We report a method for synthesizing hierarchically structured tin-carbon (Sn-C) composites via aerosol spray pyrolysis. In this method, an aqueous precursor solution containing tin(ii) chloride and sucrose is atomized, and the resultant aerosol droplets carried by an inert gas are pyrolyzed in a high-temperature tubular furnace. Owing to the unique combination of high reaction temperature and short reaction time, this method is able to achieve a hetero-structure in which small Sn particles (15 nm) are uniformly embedded in a secondary carbon particle. This procedure allows the size and size distribution of the primary Sn particles to be tuned, as well as control over the size of the secondary carbon particles by addition of polymeric surfactant in the precursor solution. When evaluated as anode materials for lithium-ion batteries, the resultant Sn-C composites demonstrate attractive electrochemical performance in terms of overall capacity, electrochemical stability, and coulombic efficiency. © 2013 The Royal Society of Chemistry.

  4. Aerosol typing - key information from aerosol studies

    Science.gov (United States)

    Mona, Lucia; Kahn, Ralph; Papagiannopoulos, Nikolaos; Holzer-Popp, Thomas; Pappalardo, Gelsomina

    2016-04-01

    classification. The harmonization of the aerosol typing procedures is a fundamental need in aerosol studies for long-term perspectives, satellite validation, and accuracy. However, the possibilities and limits in defining a common set of aerosol types for satellite missions and ground-based measurements depends on different information content among measurement techniques and for different retrieval conditions (e.g. for low aerosol content there is smaller satellite aerosol type retrieval sensitivity), as well as different historical choices. The concept of aReference database for aerosol typing (REDAT) is developed with the specific purpose of providing a dataset suitable for the comparison of typing procedures (from ground-based, and satellite measurements) and to be used as reference dataset for the modelling community. It will also allow the definition of translating rules between the different aerosol typing nomenclature, information strongly needed for the more and more increased audience of scientific data with no scientific background, as well as policy and decision makers. Acknowledgments: The research leading to these results is partially funded by ACTRIS2 Research Infrastructure Project by the European Union's Horizon 2020 research and innovation programme under the grant agreement n. 654169.

  5. Comparison of modeled estimates of inhalation exposure to aerosols during use of consumer spray products.

    Science.gov (United States)

    Park, Jihoon; Yoon, Chungsik; Lee, Kiyoung

    2018-05-30

    In the field of exposure science, various exposure assessment models have been developed to complement experimental measurements; however, few studies have been published on their validity. This study compares the estimated inhaled aerosol doses of several inhalation exposure models to experimental measurements of aerosols released from consumer spray products, and then compares deposited doses within different parts of the human respiratory tract according to deposition models. Exposure models, including the European Center for Ecotoxicology of Chemicals Targeted Risk Assessment (ECETOC TRA), the Consumer Exposure Model (CEM), SprayExpo, ConsExpo Web and ConsExpo Nano, were used to estimate the inhaled dose under various exposure scenarios, and modeled and experimental estimates were compared. The deposited dose in different respiratory regions was estimated using the International Commission on Radiological Protection model and multiple-path particle dosimetry models under the assumption of polydispersed particles. The modeled estimates of the inhaled doses were accurate in the short term, i.e., within 10 min of the initial spraying, with a differences from experimental estimates ranging from 0 to 73% among the models. However, the estimates for long-term exposure, i.e., exposure times of several hours, deviated significantly from the experimental estimates in the absence of ventilation. The differences between the experimental and modeled estimates of particle number and surface area were constant over time under ventilated conditions. ConsExpo Nano, as a nano-scale model, showed stable estimates of short-term exposure, with a difference from the experimental estimates of less than 60% for all metrics. The deposited particle estimates were similar among the deposition models, particularly in the nanoparticle range for the head airway and alveolar regions. In conclusion, the results showed that the inhalation exposure models tested in this study are suitable

  6. Comparison of models and measurements of angle-resolved scatter from irregular aerosols

    International Nuclear Information System (INIS)

    Milstein, Adam B.; Richardson, Jonathan M.

    2015-01-01

    We have developed and validated a method for modeling the elastic scattering properties of biological and inert aerosols of irregular shape at near- and mid-wave infrared wavelengths. The method, based on Gaussian random particles, calculates the ensemble-average optical cross section and Mueller scattering matrix, using the measured aerodynamic size distribution and previously-reported refractive index as inputs. The utility of the Gaussian particle model is that it is controlled by only two parameters (σ and Γ) which we have optimized such that the model best reproduces the full angle-resolved Mueller scattering matrices measured at λ=1.55 µm in the Standoff Aerosol Active Signature Testbed (SAAST). The method has been applied to wet-generated singlet biological spore samples, dry-generated biological spore clusters, and kaolin. The scattering computation is performed using the Discrete Dipole Approximation (DDA), which requires significant computational resources, and is thus implemented on LLGrid, a large parallel grid computer. For the cases presented, the best fit Gaussian particle model is in good qualitative correspondence with microscopy images of the corresponding class of particles. The measured and computed cross sections agree well within a factor of two overall, with certain cases bearing closer correspondence. In particular, the DDA reproduces the shape of the measured scatter function more accurately than Mie predictions. The DDA-computed depolarization factors are also in good agreement with measurement. - Highlights: • We model elastic scattering of biological and inert aerosols of irregular shape. • We calculate cross sections and Mueller matrix using random particle shape model. • Scatter models employ refractive index and measured size distribution as inputs. • Discrete dipole approximation (DDA) with parallelization enables model calculations. • DDA-modeled cross section and Mueller matrix agree well with measurements at 1.55 μm

  7. Comparison of shrinkage related properties of various patch repair materials

    Science.gov (United States)

    Kristiawan, S. A.; Fitrianto, R. S.

    2017-02-01

    A patch repair material has been developed in the form of unsaturated polyester resin (UPR)-mortar. The performance and durability of this material are governed by its compatibility with the concrete being repaired. One of the compatibility issue that should be tackled is the dimensional compatibility as a result of differential shrinkage between the repair material and the concrete substrate. This research aims to evaluate such shrinkage related properties of UPR-mortar and to compare with those of other patch repair materials. The investigation includes the following aspects: free shrinkage, resistance to delamination and cracking. The results indicate that UPR-mortar poses a lower free shrinkage, lower risk of both delamination and cracking tendency in comparison to other repair materials.

  8. American Association for Aerosol Research (AAAR) `95

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Fourteenth annual meeting of the American Association for Aerosol Research was held October 9-13, 1995 at Westin William Penn Hotel in Pittsburgh, PA. This volume contains the abstracts of the papers and poster sessions presented at this meeting, grouped by the session in which they were presented as follows: Radiation Effects; Aerosol Deposition; Collision Simulations and Microphysical Behavior; Filtration Theory and Measurements; Materials Synthesis; Radioactive and Nuclear Aerosols; Aerosol Formation, Thermodynamic Properties, and Behavior; Particle Contamination Issues in the Computer Industry; Pharmaceutical Aerosol Technology; Modeling Global/Regional Aerosols; Visibility; Respiratory Deposition; Biomass and Biogenic Aerosols; Aerosol Dynamics; Atmospheric Aerosols.

  9. Study of filterable materials and protection instruments by the use of radioactive aerosols

    International Nuclear Information System (INIS)

    Billard; Chevalier; Pradel

    1960-01-01

    Many filtration problems can be studied by means of radioactive aerosols. For the investigations described in this paper we have chosen the solid disintegration products of radon, the radioactive gas formed from radium, because of the facilities of generation and measurement it offers. Radon and its daughters are in fact always present in the atmosphere in sufficient concentration for certain tests. In order to improve the sensitivity of the measurements, radon from uranium ore can be used. The technique of measuring by counting α particles is rapid and easy to employ. We have thus been able to define a test for filterable substances, and to check filtering installation and individual protection instruments. (author) [fr

  10. Comparison of ambient aerosol extinction coefficients obtained from in-situ, MAX-DOAS and LIDAR measurements at Cabauw

    NARCIS (Netherlands)

    Zieger, P.; Weingartner, E.; Henzing, J.; Moerman, M.; Leeuw, G. de; Mikkilä, J.; Ehn, M.; Petäjä, T.; Clémer, K.; Roozendael, M. van; Yilmaz, S.; Frieß, U.; Irie, H.; Wagner, T.; Shaiganfar, R.; Beirle, S.; Apituley, A.; Wilson, K.; Baltensperger, U.

    2011-01-01

    In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30-40%). Since ambient aerosol particles experience hygroscopic growth at enhanced RH, their microphysical and optical properties especially the aerosol light scattering are also strongly

  11. Comparison of Aerosol Classification Results from Airborne High Spectral Resolution Lidar (HSRL) Measurements and the Calipso Vertical Feature Mask

    Science.gov (United States)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.; Froyd, K. D.; hide

    2012-01-01

    Knowledge of the vertical profile, composition, concentration, and size of aerosols is required for assessing the direct impact of aerosols on radiation, the indirect effects of aerosols on clouds and precipitation, and attributing these effects to natural and anthropogenic aerosols. Because anthropogenic aerosols are predominantly submicrometer, fine mode fraction (FMF) retrievals from satellite have been used as a tool for deriving anthropogenic aerosols. Although column and profile satellite retrievals of FMF have been performed over the ocean, such retrievals have not yet been been done over land. Consequently, uncertainty in satellite estimates of the anthropogenic component of the aerosol direct radiative forcing is greatest over land, due in large part to uncertainties in the FMF. Satellite measurements have been used to detect and evaluate aerosol impacts on clouds; however, such efforts have been hampered by the difficulty in retrieving vertically-resolved cloud condensation nuclei (CCN) concentration, which is the most direct parameter linking aerosol and clouds. Recent studies have shown correlations between average satellite derived column aerosol optical thickness (AOT) and in situ measured CCN. However, these same studies, as well as others that use detailed airborne in situ measurements have noted that vertical variability of the aerosol distribution, impacts of relative humidity, and the presence of coarse mode aerosols such as dust introduce large uncertainties in such relations.

  12. Comparison of Aerosol optical depth (AOD) derived from AERONET sunphotometer and Lidar system

    International Nuclear Information System (INIS)

    Khor, Wei Ying; Hee, Wan Shen; Tan, Fuyi; Lim, Hwee San; Jafri, Mohamad Zubir Mat; Holben, Brent

    2014-01-01

    Aerosol optical depth (AOD) is the measure of aerosols distributed within a column of air from the instrument or Earth's surface to the top of the atmosphere. In this paper, we compared the AOD measured by the Raymetrics Lidar system and AERONET sunphotometer. A total of 6 days data which was collected by both instruments were compiled and compared. Generally, AOD value calculated from Lidar data are higher than that calculated from AERONET data. Differences and similarities in the AOD data trend were observed and the corresponding explanations were done. Level 1.5 data of AERONET is estimated to have an accuracy of ±0.03, thus the Lidar data should follow the trend of the AERONET. But in this regards, this study was conducted less than one month and was very difficult to justify the differences and similarities between AOD measured by the Raymetrics Lidar system and AERONET sunphotometer. So further studies for an extended period will be needed and performed with more comprehensive LIDAR measurements. The slope of the best-fit straight line for the data points between the AOD values retrieved from LIDAR and the AERONET measurements is the closest to unity and the coefficient of determination is high (above 0. 6692). Factors which affect AOD data were discussed. As a conclusion, the trends of the AOD of both systems are similar. Yet due to some external factors, the trend will be slightly different

  13. Identification of amines in wintertime ambient particulate material using high resolution aerosol mass spectrometry

    Science.gov (United States)

    Bottenus, Courtney L. H.; Massoli, Paola; Sueper, Donna; Canagaratna, Manjula R.; VanderSchelden, Graham; Jobson, B. Thomas; VanReken, Timothy M.

    2018-05-01

    Significant amounts of amines were detected in fine particulate matter (PM) during ambient wintertime conditions in Yakima, WA, using a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Positive matrix factorization (PMF) of the organic aerosol (OA) signal resulted in a six-factor solution that included two previously unreported amine OA factors. The contributions of the amine factors were strongly episodic, but the concentration of the combined amine factors was as high as 10-15 μg m-3 (2-min average) during those episodes. In one occasion, the Amine-II component was 45% of total OA signal. The Amine-I factor was dominated by spectral peaks at m/z 86 (C5H12N+) and m/z 100 (C6H14N+), while the Amine-II factor was dominated by spectral peaks at m/z 58 (C3H8N+ and C2H6N2+) and m/z 72 (C4H10N+ and C3H8N2+). The ions dominating each amine factor showed distinct time traces, suggesting different sources or formation processes. Investigation into the chemistry of the amine factors suggests a correlation with inorganic anions for Amine-I, but no evidence that the Amine-II was being neutralized by the same inorganic ions. We also excluded the presence of organonitrates (ON) in the OA. The presence of C2H4O2+ at m/z 60 (a levoglucosan fragment) in the Amine-I spectrum suggests some influence of biomass burning emissions (more specifically residential wood combustion) in this PMF factor, but wind direction suggested that the most likely sources of these amines were agricultural activities and feedlots to the S-SW of the site.

  14. Determination of the viable material (bio aerosols) emitted from the sanitary filler Curva de Rodas of Medellin City

    International Nuclear Information System (INIS)

    Garcia Renteria, Francisco Fernando

    2002-01-01

    By means of land measurements we determined the bio aerosol (bacteria) contribution produce by the final disposal solid wastes and the contribution of this system to the atmosphere in influence places of the Medellin landfill Curva de Rodas (RSCR); To accomplish this investigation, we selected one (1) sampling station located in the disposal place, five samples stations (5) in the influence of the Curva de Rodas Landfill, three of whiches were located in the bordering neighborhoods (Fontidueno and Machado) and one control station (blank) isolated of the RSCR influence. The bioaerosols were measured using the methodology recommended by the American Society for Testing and Materials (ASTM). The average concentrations of total bacteria were of 3 colony-forming units per cubic meter of air (CFU/3 m 3 )

  15. Antarctic aerosols - A review

    Science.gov (United States)

    Shaw, Glenn E.

    1988-02-01

    Tropospheric aerosols with the diameter range of half a micron reside in the atmosphere for tens of days and teleconnect Antarctica with other regions by transport that reaches planetary scales of distances; thus, the aerosol on the Antarctic ice represents 'memory modules' of events that took place at regions separated from Antarctica by tens of thousands of kilometers. In terms of aerosol mass, the aerosol species include insoluble crustal products (less than 5 percent), transported sea-salt residues (highly variable but averaging about 10 percent), Ni-rich meteoric material, and anomalously enriched material with an unknown origin. Most (70-90 percent by mass) of the aerosol over the Antarctic ice shield, however, is the 'natural acid sulfate aerosol', apparently deriving from biological processes taking place in the surrounding oceans.

  16. Vertical profiles of fine and coarse aerosol particles over Cyprus: Comparison between in-situ drone measurements and remote sensing observations

    Science.gov (United States)

    Mamali, Dimitra; Marinou, Eleni; Pikridas, Michael; Kottas, Michael; Binietoglou, Ioannis; Kokkalis, Panagiotis; Tsekeri, Aleksandra; Amiridis, Vasilis; Sciare, Jean; Keleshis, Christos; Engelmann, Ronny; Ansmann, Albert; Russchenberg, Herman W. J.; Biskos, George

    2017-04-01

    Vertical profiles of the aerosol mass concentration derived from light detection and ranging (lidar) measurements were compared to airborne dried optical particle counter (OPC MetOne; Model 212) measurements during the INUIT-BACCHUS-ACTRIS campaign. The campaign took place in April 2016 and its main focus was the study of aerosol dust particles. During the campaign the NOA Polly-XT Raman lidar located at Nicosia (35.08° N, 33.22° E) was providing round-the-clock vertical profiles of aerosol optical properties. In addition, an unmanned aerial vehicle (UAV) carrying an OPC flew on 7 days during the first morning hours. The flights were performed at Orounda (35.1018° N, 33.0944° E) reaching altitudes of 2.5 km a.s.l, which allows comparison with a good fraction of the recorded lidar data. The polarization lidar photometer networking method (POLIPHON) was used for the estimation of the fine (non-dust) and coarse (dust) mode aerosol mass concentration profiles. This method uses as input the particle backscatter coefficient and the particle depolarization profiles of the lidar at 532 nm wavelength and derives the aerosol mass concentration. The first step in this approach makes use of the lidar observations to separate the backscatter and extinction contributions of the weakly depolarizing non-dust aerosol components from the contributions of the strongly depolarizing dust particles, under the assumption of an externally mixed two-component aerosol. In the second step, sun photometer retrievals of the fine and the coarse modes aerosol optical thickness (AOT) and volume concentration are used to calculate the associated concentrations from the extinction coefficients retrieved from the lidar. The estimated aerosol volume concentrations were converted into mass concentration with an assumption for the bulk aerosol density, and compared with the OPC measurements. The first results show agreement within the experimental uncertainty. This project received funding from the

  17. MIPAS detection of cloud and aerosol particle occurrence in the UTLS with comparison to HIRDLS and CALIOP

    Directory of Open Access Journals (Sweden)

    H. Sembhi

    2012-10-01

    detection of particle distributions in the UTLS, with extinction detection limits above 13 km often better than 10−4 km−1, with values approaching 10−5 km−1 in some cases.

    Comparisons of the new MIPAS results with cloud data from HIRDLS and CALIOP, outside of the poles, establish a good agreement in distributions (cloud and aerosol top heights and occurrence frequencies with an offset between MIPAS and the other instruments of 0.5 km to 1 km between 12 km and 20 km, consistent with vertical oversampling of extended cloud layers within the MIPAS field of view. We conclude that infrared limb sounders provide a very consistent picture of particles in the UTLS, allowing detection limits which are consistent with the lidar observations. Investigations of MIPAS data for the Mount Kasatochi volcanic eruption on the Aleutian Islands and the Black Saturday fires in Australia are used to exemplify how useful MIPAS limb sounding data were for monitoring aerosol injections into the UTLS. It is shown that the new thresholds allowed such events to be much more effectively derived from MIPAS with detection limits for these case studies of 1 × 10−5 km−1 at a wavelength of 12 μm.

  18. Chemical Composition of Aerosol from an E-Cigarette: A Quantitative Comparison with Cigarette Smoke.

    Science.gov (United States)

    Margham, Jennifer; McAdam, Kevin; Forster, Mark; Liu, Chuan; Wright, Christopher; Mariner, Derek; Proctor, Christopher

    2016-10-17

    There is interest in the relative toxicities of emissions from electronic cigarettes and tobacco cigarettes. Lists of cigarette smoke priority toxicants have been developed to focus regulatory initiatives. However, a comprehensive assessment of e-cigarette chemical emissions including all tobacco smoke Harmful and Potentially Harmful Constituents, and additional toxic species reportedly present in e-cigarette emissions, is lacking. We examined 150 chemical emissions from an e-cigarette (Vype ePen), a reference tobacco cigarette (Ky3R4F), and laboratory air/method blanks. All measurements were conducted by a contract research laboratory using ISO 17025 accredited methods. The data show that it is essential to conduct laboratory air/method measurements when measuring e-cigarette emissions, owing to the combination of low emissions and the associated impact of laboratory background that can lead to false-positive results and overestimates. Of the 150 measurands examined in the e-cigarette aerosol, 104 were not detected and 21 were present due to laboratory background. Of the 25 detected aerosol constituents, 9 were present at levels too low to be quantified and 16 were generated in whole or in part by the e-cigarette. These comprised major e-liquid constituents (nicotine, propylene glycol, and glycerol), recognized impurities in Pharmacopoeia-quality nicotine, and eight thermal decomposition products of propylene glycol or glycerol. By contrast, approximately 100 measurands were detected in mainstream cigarette smoke. Depending on the regulatory list considered and the puffing regime used, the emissions of toxicants identified for regulation were from 82 to >99% lower on a per-puff basis from the e-cigarette compared with those from Ky3R4F. Thus, the aerosol from the e-cigarette is compositionally less complex than cigarette smoke and contains significantly lower levels of toxicants. These data demonstrate that e-cigarettes can be developed that offer the potential

  19. Characterization of primary organic aerosol emissions from meat cooking, trash burning, and motor vehicles with high-resolution aerosol mass spectrometry and comparison with ambient and chamber observations.

    Science.gov (United States)

    Mohr, Claudia; Huffman, Alex; Cubison, Michael J; Aiken, Allison C; Docherty, Kenneth S; Kimmel, Joel R; Ulbrich, Ingrid M; Hannigan, Michael; Jimenez, Jose L

    2009-04-01

    Organic aerosol (OA) emissions from motor vehicles, meat-cooking and trash burning are analyzed here using a high-resolution aerosol mass spectrometer (AMS). High resolution data show that aerosols emitted by combustion engines and plastic burning are dominated by hydrocarbon-like organic compounds. Meat cooking and especially paper burning emissions contain significant fractions of oxygenated organic compounds; however, their unit-resolution mass spectral signatures are very similar to those from ambient hydrocarbon-like OA, and very different from the mass spectra of ambient secondary or oxygenated OA (OOA). Thus, primary OA from these sources is unlikelyto be a significant direct source of ambient OOA. There are significant differences in high-resolution tracer m/zs that may be useful for differentiating some of these sources. Unlike in most ambient spectra, all of these sources have low total m/z 44 and this signal is not dominated by the CO2+ ion. All sources have high m/z 57, which is low during high OOA ambient periods. Spectra from paper burning are similar to some types of biomass burning OA, with elevated m/z 60. Meat cooking aerosols also have slightly elevated m/z 60, whereas motor vehicle emissions have very low signal at this m/z.

  20. Comparison of aerosol optical depth from satellite (MODIS), sun photometer and broadband pyrheliometer ground-based observations in Cuba

    Science.gov (United States)

    Antuña-Marrero, Juan Carlos; Cachorro Revilla, Victoria; García Parrado, Frank; de Frutos Baraja, Ángel; Rodríguez Vega, Albeth; Mateos, David; Estevan Arredondo, René; Toledano, Carlos

    2018-04-01

    In the present study, we report the first comparison between the aerosol optical depth (AOD) and Ångström exponent (AE) of the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra (AODt) and Aqua (AODa) satellites and those measured using a sun photometer (AODSP) at Camagüey, Cuba, for the period 2008 to 2014. The comparison of Terra and Aqua data includes AOD derived with both deep blue (DB) and dark target (DT) algorithms from MODIS Collection 6. Combined Terra and Aqua (AODta) data were also considered. Assuming an interval of ±30 min around the overpass time and an area of 25 km around the sun photometer site, two coincidence criteria were considered: individual pairs of observations and both spatial and temporal mean values, which we call collocated daily means. The usual statistics (root mean square error, RMSE; mean absolute error, MAE; median bias, BIAS), together with linear regression analysis, are used for this comparison. Results show very similar values for both coincidence criteria: the DT algorithm generally displays better statistics and higher homogeneity than the DB algorithm in the behaviour of AODt, AODa, AODta compared to AODSP. For collocated daily means, (a) RMSEs of 0.060 and 0.062 were obtained for Terra and Aqua with the DT algorithm and 0.084 and 0.065 for the DB algorithm, (b) MAE follows the same patterns, (c) BIAS for both Terra and Aqua presents positive and negative values but its absolute values are lower for the DT algorithm; (d) combined AODta data also give lower values of these three statistical indicators for the DT algorithm; (e) both algorithms present good correlations for comparing AODt, AODa, AODta vs. AODSP, with a slight overestimation of satellite data compared to AODSP, (f). The DT algorithm yields better figures with slopes of 0.96 (Terra), 0.96 (Aqua) and 0.96 (Terra + Aqua) compared to the DB algorithm (1.07, 0.90, 0.99), which displays greater variability. Multi-annual monthly means of

  1. Intercomparison of aerosol instruments: number concentration

    International Nuclear Information System (INIS)

    Knutson, E.O.; Sinclair, D.; Tu, K.W.; Hinchliffe, L.; Franklin, H.

    1982-05-01

    An intercomparison of aerosol instruments conducted February 23-27, 1981, at the Environmental Measurements Laboratory (EML) focused on five instruments: the Pollak and TSI condensation nucleus counters; the Active Scattering Aerosol Spectrometer (ASAS-X); and two aerosol electrometers. Test aerosols of sodium chloride and ammonium fluorescein generated by nebulization/electrostatic classification were used to obtain 195 lines of comparison data. Concentrations measured by the ASAS-X and the TSI aerosol electrometer averaged respectively 1.388 and 1.581 times that measured by the Pollak. These ratios were very stable during the week and there was little effect of particle size or material. Most other comparisons were equally stable. However, a review of past work at EML and elsewhere led to the disturbing conclusion that these ratios may change from year to year, or from season to season. A filter sample was taken from microscopy, concurrent with readings from the ASAS-X and the TSI condensation nucleus counters. In this sample, the two instruments differed by 20%. Within its 20% uncertainty, the filter result matched both the TSI and ASAS-X readings

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

    Science.gov (United States)

    Ku, Bon Ki; Kulkarni, Pramod

    2012-05-01

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

  3. [Comparison of atmospheric particulate matter and aerosol optical depth in Beijing City].

    Science.gov (United States)

    Lin, Hai-Feng; Xin, Jin-Yuan; Zhang, Wen-Yu; Wang, Yue-Si; Liu, Zi-Rui; Chen, Chuan-Lei

    2013-03-01

    The pollution of particulate matter was serious in Beijing City from the synchronous observation of particulate matter mass concentration and aerosol optical characteristics in 2009. The annual mean concentrations of PM2.5 and PM10 were (65 +/- 14) microg x m(-3) and (117 +/- 31) microg x m(-3), respectively, which exceeded the national ambient air quality annual standards to be implemented in 2016. There were 35% and 26% days of 2009 that the daily standards were exceeded. There was a significant correlation between fine particulate (PM2.5) and inhalable particle (PM10), with a correlation coefficient (R) of approximately 0.90 (P 500 nm) and Angstrom exponent were (0.55 +/- 0.1) and (1.12 +/- 0.08), respectively. There were significant correlations between PM2.5, PM10 and AOD in the four seasons and the whole year, and the correlation coefficients were greater than or equal to 0.50. Furthermore, the correlation functions and coefficients had seasonal variations. The correlations were more significant in summer and autumn than in spring and winter. The annual correlation could cover up the seasonal systematic differences. The correlations between AOD revised by Mixed Layer Height and PM2.5 PM10 revised by Relative Humidity became stronger, and the exponential correlations were superior to the linear correlations.

  4. Size Distribution, Chemical Composition and Optical Properties of Atmospheric Dust in Israel: A Comparison of Urban and Desert Aerosols under Clear and Dusty Conditions.

    Science.gov (United States)

    1980-02-01

    counter (Royco 220). The instrument was calibrated with dry Latex particles of known sizes which were dispersed from a liquid suspension by the use of an...such spectra it is clear that samples from both sites contain significant amounts of gypsum, clay minerals, notably kaolin and montmorillonite clays...using a wavelength dispersive micro- probe. A comparison between aerosols from the Negev desert and Tel Aviv (under easterly flow) was conducted

  5. Premonsoon aerosol optical properties from AERONET retrievals and its probable source fields in Eastern India urban environment (Kolkata): evaluating spatial variability and its comparison with MODIS retrievals.

    Science.gov (United States)

    Priyadharshini, B.; Verma, S.

    2015-12-01

    Aerosol characteristics were examined using Aerosol Robotic Network (AERONET) and MODIS retrievals (Moderate Resolution Imaging Spectroradiometer) during the period, February to June 2009 in Eastern India, Kolkata (KOL). AERONET retrievals results for the study period manifested an aerosol optical depth - AOD (Angstrom exponent - α) in the range 0.65 - 0.81 (0.66 - 0.97) with an intermittent influence of dust. A substantial dominance of finer (coarser) particles were found in February (April) and an equal dominance of both in June. Aerosol size distribution (ASD) revealed a high volume in fine mode during June and that in April for the coarse mode. A few areas of in and around KOL, Odisha, and Sikkim influenced AOD ascertained using the Potential source contribution function (PSCF). Cluster analysis revealed preferred pathway as continental during February and both continental and marine during March to June. Episodic days identified for dust occurrence was examined and was further corroborated by MODIS Rapid response images. Further, comparative results of seven collateral AERONET sites in India, revealed a high AOD (α) at KOL during February to May (March and April) with Fine mode - FM (Coarse mode - CM) AOD of KOL being high during March and April (February to April) than other locations. Single scattering albedo (SSA) at 0.67 μm at KOL was slightly lower during February and March, with being equivalent and or higher than other sites during April to June. Comparison of AERONET - MODIS AOD at 0.55 µm for KOL (entire study period) for the collateral days revealed underestimation of MODIS during February to April and overestimation during May and June than AERONET. AERONET - MODIS AOD comparison for seven locations, during low (February) and high (June) aerosol loading, showed good agreement for few stations and divulged discrepancy for other sites.

  6. Characterisation of humic material for inter-laboratory comparison

    International Nuclear Information System (INIS)

    Peachy, D.; Bradley, A.D.; Davis, A.E.; Stuart, M.E.; Tait, B.A.R.; Vickers, B.P.; Williams, G.M.

    1988-01-01

    The characterisation and interlaboratory comparison of common humic materials by members of the European Commission's COCO group (set up to study complexes and colloids), forms part of a study of the effects of natural organic compounds in groundwater on the complexation and mobility of radionuclides. Three samples have been characterised: a sodium salt and a protonated form of the commercially available humic acid from Aldrich Chemicals; and a protonated humic acid from the Gorleben research site in Germany. Characterisation undertaken by BGS includes moisture content, elemental analysis, metal content, functional group analysis, infra-red spectroscopy, ultra-violet absorbance (E 4 /E 6 ratios), and ultra-filtration. (author)

  7. Comparison of ground based indices (API and AQI) with satellite based aerosol products.

    Science.gov (United States)

    Zheng, Sheng; Cao, Chun-Xiang; Singh, Ramesh P

    2014-08-01

    Air quality in mega cities is one of the major concerns due to serious health issues and its indirect impact to the climate. Among mega cities, Beijing city is considered as one of the densely populated cities with extremely poor air quality. The meteorological parameters (wind, surface temperature, air temperature and relative humidity) control the dynamics and dispersion of air pollution. China National Environmental Monitoring Centre (CNEMC) started air pollution index (API) as of 2000 to evaluate air quality, but over the years, it was felt that the air quality is not well represented by API. Recently, the Ministry of Environmental Protection (MEP) of the People's Republic of China (PRC) started using a new index "air quality index (AQI)" from January 2013. We have compared API and AQI with three different MODIS (MODIS - Moderate Resolution Imaging SpectroRadiometer, onboard the Terra/Aqua satellites) AOD (aerosol optical depth) products for ten months, January-October, 2013. The correlation between AQI and Aqua Deep Blue AOD was found to be reasonably good as compared with API, mainly due to inclusion of PM2.5 in the calculation of AQI. In addition, for every month, the correlation coefficient between AQI and Aqua Deep Blue AOD was found to be relatively higher in the month of February to May. According to the monthly average distribution of precipitation, temperature, and PM10, the air quality in the months of June-September was better as compared to those in the months of February-May. AQI and Aqua Deep Blue AOD show highly polluted days associated with dust event, representing true air quality of Beijing. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Comparison of Geometrical Layouts for a Multi-Box Aerosol Model from a Single-Chamber Dispersion Study

    Directory of Open Access Journals (Sweden)

    Alexander C. Ø. Jensen

    2018-04-01

    Full Text Available Models are increasingly used to estimate and pre-emptively calculate the occupational exposure of airborne released particulate matter. Typical two-box models assume instant and fully mixed air volumes, which can potentially cause issues in cases with fast processes, slow air mixing, and/or large volumes. In this study, we present an aerosol dispersion model and validate it by comparing the modelled concentrations with concentrations measured during chamber experiments. We investigated whether a better estimation of concentrations was possible by using different geometrical layouts rather than a typical two-box layout. A one-box, two-box, and two three-box layouts were used. The one box model was found to underestimate the concentrations close to the source, while overestimating the concentrations in the far field. The two-box model layout performed well based on comparisons from the chamber study in systems with a steady source concentration for both slow and fast mixing. The three-box layout was found to better estimate the concentrations and the timing of the peaks for fluctuating concentrations than the one-box or two-box layouts under relatively slow mixing conditions. This finding suggests that industry-relevant scaled volumes should be tested in practice to gain more knowledge about when to use the two-box or the three-box layout schemes for multi-box models.

  9. Statistical variability comparison in MODIS and AERONET derived aerosol optical depth over Indo-Gangetic Plains using time series modeling.

    Science.gov (United States)

    Soni, Kirti; Parmar, Kulwinder Singh; Kapoor, Sangeeta; Kumar, Nishant

    2016-05-15

    A lot of studies in the literature of Aerosol Optical Depth (AOD) done by using Moderate Resolution Imaging Spectroradiometer (MODIS) derived data, but the accuracy of satellite data in comparison to ground data derived from ARrosol Robotic NETwork (AERONET) has been always questionable. So to overcome from this situation, comparative study of a comprehensive ground based and satellite data for the period of 2001-2012 is modeled. The time series model is used for the accurate prediction of AOD and statistical variability is compared to assess the performance of the model in both cases. Root mean square error (RMSE), mean absolute percentage error (MAPE), stationary R-squared, R-squared, maximum absolute percentage error (MAPE), normalized Bayesian information criterion (NBIC) and Ljung-Box methods are used to check the applicability and validity of the developed ARIMA models revealing significant precision in the model performance. It was found that, it is possible to predict the AOD by statistical modeling using time series obtained from past data of MODIS and AERONET as input data. Moreover, the result shows that MODIS data can be formed from AERONET data by adding 0.251627 ± 0.133589 and vice-versa by subtracting. From the forecast available for AODs for the next four years (2013-2017) by using the developed ARIMA model, it is concluded that the forecasted ground AOD has increased trend. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. The penetration of aerosols through fine capillaries

    International Nuclear Information System (INIS)

    Mitchell, J.P.; Edwards, R.T.; Ball, M.H.E.

    1989-10-01

    A novel experimental technique has been developed to study the penetration of aerosol particles ranging from about 1 to 15 μm aerodynamic diameter through capillaries varying from 20 to 80 μm bore and from 10 to 50 mm in length. When the driving pressure was 100 kPa, the penetration of the airborne particles was considerably smaller than expected from a simple comparison of particle diameter with the bore of the capillary. Particle size distributions determined after penetration through the capillaries were in almost all cases similar to the particle size distribution of the aerosol at the capillary entrance. This lack of size-selectivity can be explained in terms of the capillary behaving as a conventional suction-based sampler from a near still (calm) air environment. The resulting particle penetration data are important in assessing the potential for the leakage of aerosols through seals in containers used to transport radioactive materials. (author)

  11. Comparison of Subcuticular Suture Materials in Cesarean Skin Closure

    Directory of Open Access Journals (Sweden)

    Pınar Solmaz Hasdemir

    2015-01-01

    Full Text Available Aim. Comparison of the rate of wound complications, pain, and patient satisfaction based on used subcuticular suture material. Methods. A total of 250 consecutive women undergoing primary and repeat cesarean section with low transverse incision were prospectively included. The primary outcome was wound complication rate including infection, dehiscence, hematoma, and hypertrophic scar formation within a 6-week period after operation. Secondary outcomes were skin closure time, the need for use of additional analgesic agent, pain score on numeric rating scale, cosmetic score, and patient scar satisfaction scale. Results. Absorbable polyglactin was used in 108 patients and nonabsorbable polypropylene was used in 142 patients. Wound complication rates were similar in primary and repeat cesarean groups based on the type of suture material. Skin closure time is longer in nonabsorbable suture material group in both primary and repeat cesarean groups. There was no difference between groups in terms of postoperative pain, need for additional analgesic use, late phase pain, and itching at the scar. Although the cosmetic results tended to be better in the nonabsorbable group in primary surgery patients, there was no significant difference in the visual satisfaction of the patients. Conclusions. Absorbable and nonabsorbable suture materials are comparable in cesarean section operation skin closure.

  12. Reference materials and interlaboratory comparison for actinide analysis

    International Nuclear Information System (INIS)

    Hanssens, Alain; Viallesoubranne, Carole; Roche, Claude; Liozon, Gerard

    2008-01-01

    Measurement quality is crucial for the safety of nuclear facilities and is a primary requirement for fissile material monitoring and accountancy. CETAMA (Cea Committee for the establishment of analysis methods), in collaboration with Cea and AREVA laboratories, fabricates certified reference materials and organizes interlaboratory comparison programs for plutonium and uranium assay in solution. A new plutonium metal measurement standard (MP3) is currently being prepared by Cea and is a subject of cooperative work in view of its certification and use by analysis laboratories. U and Pu interlaboratory comparisons are carried out at regular intervals on benchmark samples in coordination with working groups from French nuclear laboratories. These programs are supported by international cooperation. 'Chemical' methods (potentiometry, gravimetric analysis, etc.) generally provide the best accuracy. Coulometry is the benchmark technique for plutonium assay: its metrological qualities should be an incentive for wider use by laboratories performing precise control assays of plutonium as well as uranium. Gravimetric analysis provides excellent results for analysis of pure uranyl nitrate solutions. In view of its many advantages we encourage laboratories to employ this technique to assay pure U or Pu solutions. 'Physical' or 'physicochemical' methods are increasingly used, and their performance has improved. K-edge absorption spectrometry and isotope dilution mass spectrometry are capable of reaching measurement quality levels comparable to those of the best 'chemical' methods. (authors)

  13. Reference materials and interlaboratory comparison for actinide analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hanssens, Alain; Viallesoubranne, Carole; Roche, Claude; Liozon, Gerard [Commissariat a l' Energie Atomique, Marcoule: BP 17171, 30207 Bagnols sur Ceze (France)

    2008-07-01

    Measurement quality is crucial for the safety of nuclear facilities and is a primary requirement for fissile material monitoring and accountancy. CETAMA (Cea Committee for the establishment of analysis methods), in collaboration with Cea and AREVA laboratories, fabricates certified reference materials and organizes interlaboratory comparison programs for plutonium and uranium assay in solution. A new plutonium metal measurement standard (MP3) is currently being prepared by Cea and is a subject of cooperative work in view of its certification and use by analysis laboratories. U and Pu interlaboratory comparisons are carried out at regular intervals on benchmark samples in coordination with working groups from French nuclear laboratories. These programs are supported by international cooperation. 'Chemical' methods (potentiometry, gravimetric analysis, etc.) generally provide the best accuracy. Coulometry is the benchmark technique for plutonium assay: its metrological qualities should be an incentive for wider use by laboratories performing precise control assays of plutonium as well as uranium. Gravimetric analysis provides excellent results for analysis of pure uranyl nitrate solutions. In view of its many advantages we encourage laboratories to employ this technique to assay pure U or Pu solutions. 'Physical' or 'physicochemical' methods are increasingly used, and their performance has improved. K-edge absorption spectrometry and isotope dilution mass spectrometry are capable of reaching measurement quality levels comparable to those of the best 'chemical' methods. (authors)

  14. Dry aerosol of monodisperse millimicrospheres for ventilation imaging: Production, delivery system, and clinical results in comparison with /sup 81m/Kr and /sup 127/Xe

    Energy Technology Data Exchange (ETDEWEB)

    Koehn, H; Mostbeck, A; Klech, H; Kummer, F; Angelberger, P; Strigl, A; Zolle, I

    1985-05-01

    The production of monodisperse human albumin millimicrospheres (diameter 1 ..mu..m) and labeling with /sup 99m/Tc is described. A system constructed to nebulize and deliver a dry aerosol yielded a lung delivery efficiency of approximately 25%. In 48 patients without and with varying degrees of chronic obstructive lung disease, quantitative comparison with /sup 81m/Kr (penetration index, regional distribution of activity in the lungs) demonstrated similar penetration of the particles to the lung periphery (r = 0.89 and r = 0.94, respectively). Qualitative comparison with /sup 81m/Kr or /sup 127/Xe showed complete or a high degree of diagnostic agreement in all but one patient. Semiquantitative scoring of hot spots as a substrate of local turbulent airflow showed a close inverse correlation (r = -0.82) with the forced expiratory volume in 1 s (FEV 1.0%), thus providing additional information about the severity of the airway obstruction. In 24 patients with suspected pulmonary embolism, complete agreement between aerosol and /sup 81m/Kr images was found in all patients studied. For same-day ventilation/perfusion studies, labeling of the millimicrospheres with /sup 111/In yielded images of comparable quality to those obtained with the /sup 99m/Tc-labeled aerosol.

  15. Development and Characterization of a Thermodenuder for Aerosol Volatility Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Timothy Onasch

    2009-09-09

    This SBIR Phase I project addressed the critical need for improved characterization of carbonaceous aerosol species in the atmosphere. The proposed work focused on the development of a thermodenuder (TD) system capable of systematically measuring volatility profiles of primary and secondary organic aerosol species and providing insight into the effects of absorbing and nonabsorbing organic coatings on particle absorption properties. This work provided the fundamental framework for the generation of essential information needed for improved predictions of ambient aerosol loadings and radiative properties by atmospheric chemistry models. As part of this work, Aerodyne Research, Inc. (ARI) continued to develop and test, with the final objective of commercialization, an improved thermodenuder system that can be used in series with any aerosol instrument or suite of instruments (e.g., aerosol mass spectrometers-AMS, scanning mobility particle sizers-SMPS, photoacoustic absorption spectrometers-PAS, etc.) to obtain aerosol chemical, physical, and optical properties as a function of particle volatility. In particular, we provided the proof of concept for the direct coupling of our improved TD design with a full microphysical model to obtain volatility profiles for different organic aerosol components and to allow for meaningful comparisons between different TD-derived aerosol measurements. In a TD, particles are passed through a heated zone and a denuding (activated charcoal) zone to remove semi-volatile material. Changes in particle size, number concentration, optical absorption, and chemical composition are subsequently detected with aerosol instrumentation. The aerosol volatility profiles provided by the TD will strengthen organic aerosol emission inventories, provide further insight into secondary aerosol formation mechanisms, and provide an important measure of particle absorption (including brown carbon contributions and identification, and absorption enhancements

  16. Highlights from 4STAR Sky-Scanning Retrievals of Aerosol Intensive Optical Properties from Multiple Field Campaigns with Detailed Comparisons of SSA Reported During SEAC4RS

    Science.gov (United States)

    Dunagan, Stephen E.

    2016-01-01

    The 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument combines airborne sun tracking capabilities of the Ames Airborne Tracking Sun Photometer (AATS-14) with AERONET (Aerosol Robotic Network)-like sky-scanning capability and adds state-of-the-art fiber-coupled grating spectrometry to yield hyperspectral measurements of direct solar irradiance and angularly resolved sky radiance. The combination of sun-tracking and sky-scanning capability enables retrievals of wavelength-dependent aerosol optical depth (AOD), mode-resolved aerosol size distribution (SD), asphericity, and complex refractive index, and thus also the scattering phase function, asymmetry parameter, single-scattering albedo (SSA), and absorption aerosol optical thickness (AAOT). From 2012 to 2014 4STAR participated in four major field campaigns: the U.S. Dept. of Energy's TCAP (Two-Column Aerosol Project) I & II campaigns, and NASA's SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys) and ARISE (Arctic Radiation - IceBridge Sea & Ice Experiment) campaigns. Establishing a strong performance record, 4STAR operated successfully on all flights conducted during each of these campaigns. Sky radiance spectra from scans in either constant azimuth (principal plane) or constant zenith angle (almucantar) were interspersed with direct beam measurements during level legs. During SEAC4RS and ARISE, 4STAR airborne measurements were augmented with flight-level albedo from the collocated Shortwave Spectral Flux Radiometer (SSFR) providing improved specification of below-aircraft radiative conditions for the retrieval. Calibrated radiances and retrieved products will be presented with particular emphasis on detailed comparisons of ambient SSA retrievals and measurements during SEAC4RS from 4STAR, AERONET, HSRL2 (High Spectral Resolution Lidar), and from in situ measurements.

  17. Longevity of dental amalgam in comparison to composite materials

    Directory of Open Access Journals (Sweden)

    Windisch, Friederike

    2008-11-01

    Full Text Available Health political background: Caries is one of the most prevalent diseases worldwide. For (direct restaurations of carious lesions, tooth-coloured composite materials are increasingly used. The compulsory health insurance pays for composite fillings in front teeth; in posterior teeth, patients have to bear the extra cost. Scientific background: Amalgam is an alloy of mercury and other metals and has been used in dentistry for more than one hundred and fifty years. Composites consist of a resin matrix and chemically bonded fillers. They have been used for about fifty years in front teeth. Amalgam has a long longevity; the further development of composites has also shown improvements regarding their longevity. Research questions: This HTA-report aims to evaluate the longevity (failure rate, median survival time (MST, median age of direct amalgam fillings in comparison to direct composite fillings in permanent teeth from a medical and economical perspective and discusses the ethical, legal and social aspects of using these filling materials. Methods: The systematic literature search yielded a total of 1,149 abstracts. After a two-step selection process based on defined criteria 25 publications remained to be assessed. Results: The medical studies report a longer longevity for amalgam fillings than for composite fillings. However, the results of these studies show a large heterogeneity. No publication on the costs or the cost-effectiveness of amalgam and composite fillings exists for Germany. The economic analyses (NL, SWE, GB report higher costs for composite fillings when longevity is assumed equal (for an observation period of five years or longer for amalgam compared to composite fillings. These higher costs are due to the higher complexity of placing composite fillings. Discussion: Due to different study designs and insufficient documentation of study details, a comparison of different studies on longevity of direct amalgam and composite

  18. Comparison of three aerosol chemical characterization techniques utilizing PTR-ToF-MS: a study on freshly formed and aged biogenic SOA

    Science.gov (United States)

    Gkatzelis, Georgios I.; Tillmann, Ralf; Hohaus, Thorsten; Müller, Markus; Eichler, Philipp; Xu, Kang-Ming; Schlag, Patrick; Schmitt, Sebastian H.; Wegener, Robert; Kaminski, Martin; Holzinger, Rupert; Wisthaler, Armin; Kiendler-Scharr, Astrid

    2018-03-01

    An intercomparison of different aerosol chemical characterization techniques has been performed as part of a chamber study of biogenic secondary organic aerosol (BSOA) formation and aging at the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction chamber). Three different aerosol sampling techniques - the aerosol collection module (ACM), the chemical analysis of aerosol online (CHARON) and the collection thermal-desorption unit (TD) were connected to proton transfer reaction time-of-flight mass spectrometers (PTR-ToF-MSs) to provide chemical characterization of the SOA. The techniques were compared among each other and to results from an aerosol mass spectrometer (AMS) and a scanning mobility particle sizer (SMPS). The experiments investigated SOA formation from the ozonolysis of β-pinene, limonene, a β-pinene-limonene mix and real plant emissions from Pinus sylvestris L. (Scots pine). The SOA was subsequently aged by photo-oxidation, except for limonene SOA, which was aged by NO3 oxidation. Despite significant differences in the aerosol collection and desorption methods of the PTR-based techniques, the determined chemical composition, i.e. the same major contributing signals, was found by all instruments for the different chemical systems studied. These signals could be attributed to known products expected from the oxidation of the examined monoterpenes. The sampling and desorption method of ACM and TD provided additional information on the volatility of individual compounds and showed relatively good agreement. Averaged over all experiments, the total aerosol mass recovery compared to an SMPS varied within 80 ± 10, 51 ± 5 and 27 ± 3 % for CHARON, ACM and TD, respectively. Comparison to the oxygen-to-carbon ratios (O : C) obtained by AMS showed that all PTR-based techniques observed lower O : C ratios, indicating a loss of molecular oxygen either during aerosol sampling or detection. The differences in total

  19. Comparison of three aerosol chemical characterization techniques utilizing PTR-ToF-MS: a study on freshly formed and aged biogenic SOA

    Directory of Open Access Journals (Sweden)

    G. I. Gkatzelis

    2018-03-01

    Full Text Available An intercomparison of different aerosol chemical characterization techniques has been performed as part of a chamber study of biogenic secondary organic aerosol (BSOA formation and aging at the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction chamber. Three different aerosol sampling techniques – the aerosol collection module (ACM, the chemical analysis of aerosol online (CHARON and the collection thermal-desorption unit (TD were connected to proton transfer reaction time-of-flight mass spectrometers (PTR-ToF-MSs to provide chemical characterization of the SOA. The techniques were compared among each other and to results from an aerosol mass spectrometer (AMS and a scanning mobility particle sizer (SMPS. The experiments investigated SOA formation from the ozonolysis of β-pinene, limonene, a β-pinene–limonene mix and real plant emissions from Pinus sylvestris L. (Scots pine. The SOA was subsequently aged by photo-oxidation, except for limonene SOA, which was aged by NO3 oxidation. Despite significant differences in the aerosol collection and desorption methods of the PTR-based techniques, the determined chemical composition, i.e. the same major contributing signals, was found by all instruments for the different chemical systems studied. These signals could be attributed to known products expected from the oxidation of the examined monoterpenes. The sampling and desorption method of ACM and TD provided additional information on the volatility of individual compounds and showed relatively good agreement. Averaged over all experiments, the total aerosol mass recovery compared to an SMPS varied within 80 ± 10, 51 ± 5 and 27 ± 3 % for CHARON, ACM and TD, respectively. Comparison to the oxygen-to-carbon ratios (O : C obtained by AMS showed that all PTR-based techniques observed lower O : C ratios, indicating a loss of molecular oxygen either during aerosol sampling or

  20. A Comparison of Aerosolization and Homogenization Techniques for Production of Alginate Microparticles for Delivery of Corticosteroids to the Colon.

    Science.gov (United States)

    Samak, Yassmin O; El Massik, Magda; Coombes, Allan G A

    2017-01-01

    Alginate microparticles incorporating hydrocortisone hemisuccinate were produced by aerosolization and homogenization methods to investigate their potential for colonic drug delivery. Microparticle stabilization was achieved by CaCl 2 crosslinking solution (0.5 M and 1 M), and drug loading was accomplished by diffusion into blank microparticles or by direct encapsulation. Homogenization method produced smaller microparticles (45-50 μm), compared to aerosolization (65-90 μm). High drug loadings (40% wt/wt) were obtained for diffusion-loaded aerosolized microparticles. Aerosolized microparticles suppressed drug release in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) prior to drug release in simulated colonic fluid (SCF) to a higher extent than homogenized microparticles. Microparticles prepared using aerosolization or homogenization (1 M CaCl 2 , diffusion loaded) released 5% and 17% of drug content after 2 h in SGF and 4 h in SIF, respectively, and 75% after 12 h in SCF. Thus, aerosolization and homogenization techniques show potential for producing alginate microparticles for colonic drug delivery in the treatment of inflammatory bowel disease. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  1. Statistical Comparison of Cloud and Aerosol Vertical Properties between Two Eastern China Regions Based on CloudSat/CALIPSO Data

    Directory of Open Access Journals (Sweden)

    Yujun Qiu

    2017-01-01

    Full Text Available The relationship between cloud and aerosol properties was investigated over two 4° × 4° adjacent regions in the south (R1 and in the north (R2 in eastern China. The CloudSat/CALIPSO data were used to extract the cloud and aerosol profiles properties. The mean value of cloud occurrence probability (COP was the highest in the mixed cloud layer (−40°C~0°C and the lowest in the warm cloud layer (>0°C. The atmospheric humidity was more statistically relevant to COP in the warm cloud layer than aerosol condition. The differences in COP between the two regions in the mixed cloud layer and ice cloud layer (<−40°C had good correlations with those in the aerosol extinction coefficient. A radar reflectivity factor greater than −10 dBZ occurred mainly in warm cloud layers and mixed cloud layers. A high-COP zone appeared in the above-0°C layer with cloud thicknesses of 2-3 km in both regions and in all the four seasons, but the distribution of the zonal layer in R2 was more continuous than that in R1, which was consistent with the higher aerosol optical thickness in R2 than in R1 in the above-0°C layer, indicating a positive correlation between aerosol and cloud probability.

  2. Microparticles and human health: particulate materials, trace metals elements and black carbon in aerosols collected at Andravoahangy-Antananarivo, Madagascar

    International Nuclear Information System (INIS)

    Rasoazanany, E. O.; Andriamahenina, N. N.; Harinoely, M.; Ravoson, H. N.; Randriamanivo, L. V.; Raoelina Andriambololona; Ramaherison, H.

    2013-01-01

    The present work is to determine the concentrations of microparticles having diameter inferior to 10 μm (PM 10 ), the metal trace elements and the black carbon in the aerosols sampled in Andravoahangy-Antananarivo, Madagascar in 2008. The air sampler GENT is used to collect aerosol samples. The total reflection X-ray fluorescence spectrometer is used for qualitative and quantitative analysis of simultaneous way all metallic trace elements contained in the aerosols. The M43D reflectometer permits to measure the reflectances in order to determine the black carbon concentrations. The results show that the average concentrations of the particulate matters PM 2,5-10 are higher than those of PM 2,5 . The average concentrations of PM 10 in the aerosols are exceeding the World Health Organisation (WHO) and European Union guidelines, set at 50 μg.m -3 and those of PM 2,5 are higher than the 2005 WHO (25 μg.m-3) and the United States Environment Protection Agency (35 μg.m -3 ) guidelines. Consequently, air quality in Andravoahangy does not respect these daily guidelines. The identified metallic trace elements in the aerosols are Ti, Cr, Mn, Fe, Ni, Cu, Zn and Pb. The average concentrations of these elements are also higher in the coarse particles than in the fine particles. The concentrations of black carbon are higher in the fine particles. The maximum value is 9.12 μg.m -3 . [fr

  3. Experimental Study on the Comparison of the Material Properties of Glass Wool Used as Building Materials

    Directory of Open Access Journals (Sweden)

    Kyoung-Woo KIM

    2014-04-01

    Full Text Available Artificial mineral fibers such as glass wool or stone wool are commonly used in building walls, ceilings and floors as a major insulation material for buildings. Among the material properties of building materials, thermal conductivity, the sound absorption coefficient, compressibility, and dynamic stiffness are regarded as important performance requirements since they directly affect the thermal and acoustic properties of the building. This study measured the changes of the thermal and acoustical performances of glass wool that was actually installed for a long time to the outer wall of a building as an insulation material through a comparison with recently produced glass wool. The results showed that the measured thermal conductivities of the old and the new specimens both rise with an increase of temperature, showing quite similar results in both specimens over temperature ranges of (0 – 20 ºC. The noise reduction coefficient decreased by 0.1 in the old specimen and the difference of the compressibilities in both specimens was shown to be 7.32 mm. The dynamic stiffness of the old specimen was found to be 1.28 MN/m3 higher than that of the new specimen.DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3714

  4. Comparison of HFNC, bubble CPAP and SiPAP on aerosol delivery in neonates: An in-vitro study.

    Science.gov (United States)

    Sunbul, Fatemah S; Fink, James B; Harwood, Robert; Sheard, Meryl M; Zimmerman, Ralph D; Ari, Arzu

    2015-11-01

    Aerosol drug delivery via high flow nasal cannula (HFNC), bubble continuous positive airway pressure (CPAP), and synchronized inspiratory positive airway pressure (SiPAP) has not been quantified in spontaneously breathing premature infants. The purpose of this study was to compare aerosol delivery via HFNC, bubble CPAP, and SiPAP in a model of a simulated spontaneously breathing preterm infant. The types of CPAP systems and nebulizer positions used during aerosol therapy will impact aerosol deposition in simulated spontaneously breathing infants. Quantitative, comparative, in-vitro study. A breath simulator was set to preterm infant settings (VT : 9 ml, RR: 50 bpm and Ti: 0.5 sec) and connected to the trachea of an anatomical upper airway model of a preterm infant via collecting filter distal to the trachea. The HFNC (Optiflow; Fisher & Paykel), Bubble CPAP (Fisher & Paykel), and SiPAP (Carefusion) were attached to the nares of the model via each device's proprietary nasal cannula and set to deliver a baseline of 5 cm H2 O pressure. Albuterol sulfate (2.5 mg/0.5 ml) was aerosolized with a mesh nebulizer (Aeroneb Solo) positioned(1) proximal to the patient and(2) prior to the humidifier (n = 5). The drug was eluted from the filter with 0.1 N HCl and analyzed via spectrophotometry (276 nm). Data were analyzed using descriptive statistics, t-tests, and one-way analysis of variance (ANOVA), with P CPAP (1.24 ± 0.24; p = 0.008). Placement of the nebulizer prior to the humidifier increased deposition with all devices (P < 0.05). Aerosol can be delivered via all three devices used in this study. Device selection and nebulizer position impacted aerosol delivery in this simulated model of a spontaneously breathing preterm infant. © 2014 Wiley Periodicals, Inc.

  5. Aerosol extinction profiles at 525 nm and 1020 nm derived from ACE imager data: comparisons with GOMOS, SAGE II, SAGE III, POAM III, and OSIRIS

    Directory of Open Access Journals (Sweden)

    F. Vanhellemont

    2008-04-01

    Full Text Available The Canadian ACE (Atmospheric Chemistry Experiment mission is dedicated to the retrieval of a large number of atmospheric trace gas species using the solar occultation technique in the infrared and UV/visible spectral domain. However, two additional solar disk imagers (at 525 nm and 1020 nm were added for a number of reasons, including the retrieval of aerosol and cloud products. In this paper, we present first comparison results for these imager aerosol/cloud optical extinction coefficient profiles, with the ones derived from measurements performed by 3 solar occultation instruments (SAGE II, SAGE III, POAM III, one stellar occultation instrument (GOMOS and one limb sounder (OSIRIS. The results indicate that the ACE imager profiles are of good quality in the upper troposphere/lower stratosphere, although the aerosol extinction for the visible channel at 525 nm contains a significant negative bias at higher altitudes, while the relative differences indicate that ACE profiles are almost always too high at 1020 nm. Both problems are probably related to ACE imager instrumental issues.

  6. Organic aerosols

    International Nuclear Information System (INIS)

    Penner, J.E.

    1994-01-01

    Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN

  7. Sodium aerosols and vapour trapping

    International Nuclear Information System (INIS)

    Julien-Dolias, M.; Pradel, P.

    1986-01-01

    This paper gives a survey of the parameters influencing aerosols behaviour in argon cover gas, production and evolution. A comparison is given between experimental results obtained on large pools and theoretical calculations obtained with the code ''Aerosols A2'' in the field of separation in a pipe and deposit on cold surfaces

  8. Atmospheric aerosol variability above the Paris Area during the 2015 heat wave - Comparison with the 2003 and 2006 heat waves

    Science.gov (United States)

    Chazette, Patrick; Totems, Julien; Shang, Xiaoxia

    2017-12-01

    The aerosol layers during the heat wave of July 2015 over Paris Area have been studied using a N2-Raman lidar with co- and cross-polarized channels. The lidar observations are examined to allow the identification of main aerosol types and their origins, in synergy with measurements of the AERONET sunphotometer network and back trajectory studies from the HYSPLIT model. The results are compatible with spaceborne observations of MODIS and CALIOP. As for previous heat waves of August 2003 and July 2006 occurring in France, the aerosol optical thickness is very large, up to 0.8 at the lidar wavelength of 355 nm (between 0.5 and 0.7 at 550 nm). However, air mass trajectories highlight that the observed aerosol layers may have multiple and diverse origins during the 2015 heat wave (North America, Northwest Africa, Southern and Northern Europe). Biomass burning, pollution and desert dust aerosols have been identified, using linear particle depolarization ratio, lidar ratio and analysis of back trajectories initiated at the altitudes and arrival times of the plumes. These layers are elevated and are shown to have little impact on surface aerosol concentrations (PM10 < 40 μg m-3 or PM2.5 < 25 μg m-3) and therefore no influence on the local air quality during the 2015 heat wave, unlike in 2003 and 2006. However, they significantly modify the radiative budget by trapping part of the solar ingoing/outgoing fluxes, which leads to a mean aerosol radiative forcing close to +50 ± 17 Wm-2 per aerosol optical thickness unit at 550 nm (AOT550) for solar zenith angles between 55 and 75°, which are available from sunphotometer measurements. This value is smaller than those of the 2003 and 2006 heat waves, which are assessed to be +95 ± 13 and +70 ± 18 Wm-2/AOT550, respectively. The differences between the heat wave of 2015 and the others are mainly due to both the nature and the diversity of aerosols, as indicated by the dispersion of the single scattering albedo distributions at

  9. Theoretical studies on aerosol agglomeration processes

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  10. Theoretical studies on aerosol agglomeration processes

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  11. Radioactive aerosols

    International Nuclear Information System (INIS)

    Chamberlain, A.C.

    1991-01-01

    Radon. Fission product aerosols. Radioiodine. Tritium. Plutonium. Mass transfer of radioactive vapours and aerosols. Studies with radioactive particles and human subjects. Index. This paper explores the environmental and health aspects of radioactive aerosols. Covers radioactive nuclides of potential concern to public health and applications to the study of boundary layer transport. Contains bibliographic references. Suitable for environmental chemistry collections in academic and research libraries

  12. Comparison of aerosol optical depths from the Ozone Monitoring Instrument (OMI on Aura with results from airborne sunphotometry, other space and ground measurements during MILAGRO/INTEX-B

    Directory of Open Access Journals (Sweden)

    J. M. Livingston

    2009-09-01

    Full Text Available Airborne sunphotometer measurements are used to evaluate retrievals of extinction aerosol optical depth (AOD from spatially coincident and temporally near-coincident measurements by the Ozone Monitoring Instrument (OMI aboard the Aura satellite during the March 2006 Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment (MILAGRO/INTEX-B. The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS flew on nine missions over the Gulf of Mexico and four in or near the Mexico City area. Retrievals of AOD from near-coincident AATS and OMI measurements are compared for three flights over the Gulf of Mexico for flight segments when the aircraft flew at altitudes 60–70 m above sea level, and for one flight over the Mexico City area where the aircraft was restricted to altitudes ~320–800 m above ground level over the rural area and ~550–750 m over the city. OMI-measured top of atmosphere (TOA reflectances are routinely inverted to yield aerosol products such as AOD and aerosol absorption optical depth (AAOD using two different retrieval algorithms: a near-UV (OMAERUV and a multiwavelength (OMAERO technique. This study uses the archived Collection 3 data products from both algorithms. In particular, AATS and OMI AOD comparisons are presented for AATS data acquired in 20 OMAERUV retrieval pixels (15 over water and 19 OMAERO pixels (also 15 over water. At least four pixels for one of the over-water coincidences and all pixels for the over-land case were cloud-free. Coincident AOD retrievals from 17 pixels of the Moderate Resolution Imaging Spectroradiometer (MODIS aboard Aqua are available for two of the over-water flights and are shown to agree with AATS AODs to within root mean square (RMS differences of 0.00–0.06, depending on wavelength. Near-coincident ground-based AOD measurements from ground-based sun/sky radiometers operated as part of the Aerosol Robotic Network (AERONET

  13. Emergency Protection from Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, G.A.

    2001-11-13

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  14. Emergency protection from aerosols

    International Nuclear Information System (INIS)

    Cristy, G.A.; Chester, C.V.

    1981-07-01

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved

  15. Study on the deposition patterns of aerosol inhalation scintigraphy, 1; Comparison of the deposition patterns of aerosol inhalation scintigraphy with lung function tests in pulmonary diseases

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Hiroyuki [Nara Medical Univ., Kashihara (Japan)

    1989-06-01

    The deposition patterns of aerosol inhalation scintigraphies and lung function tests were studied in 102 cases; 64 cases of obstructive pulmonary diseases (19 pulmonary emphysema, 27 diffuse panbronchiolitis, 18 chronic bronchitis) and 38 restrictive pulmonary disease (15 idiopathic interstitial pneumonia, 16 pulmonary asbestosis, 7 interstitial pneumonia due to collagen vascular disease). The deposition patterns were classified into 5 patterns (Type A:normal homogenous distribution; Type B: mildly unhomogenous distribution; Type C: severely unhomogenous distribution mingled with hot spots; Type D: non-hilar hot spots; and Type E: hilar hot spots). The deposition patterns of restrictive pulmonary diseases were markedly abnormal as well as obstructive pulmonary diseases. The deposition patterns showed mainly Types C, D and E in obstructive pulmonary diseases, Type B in restrictive pulmonary diseases. The deposition patterns showed mainly Type E in pulmonary emphysema, Types C and D in diffuse panbronchiolitis, Types A, B and C in chronic bronchitis, Type B in idiopathic interstitial pneumonia interstitial pneumonia due to collagen vascular disease, Types B and C in pulmonary asbestosis. The deposition patterns correlated well with %FEV{sub 1.0} which was a good indicator of the severity of obstructive pulmonary diseases and restrictive pulmonary diseases. Furthermore, the mean %FEV{sub 1.0} in obstructive pulmonary diseases was nearly equal to the mean %FEV{sub 1.0} in restrictive pulmonary diseases in each type of the deposition patterns. (J.P.N.).

  16. Comparison of european computer codes relative to the aerosol behavior in PWR containment buildings during severe core damage accidents

    International Nuclear Information System (INIS)

    Fermandjian, J.; Beonio-Brocchieri, F.

    1986-09-01

    The present study concerns a comparative exercise, performed within the framework of the Commission of the European Communities, of the computer codes used in reactor safety in order to assess their capability of realistically describing the aerosol behavior in PWR reactor containment buildings during severe accidents. The codes included in the present study are the following: AEROSIM-M, AEROSOLS/Bl, CORRAL-2, NAUA Mod5. In AEROSIM-M, AEROSOLS/Bl and NAUA Mod5, the integro-differential equation for the evolution of the particle mass distribution is approximated by a set of coupled first order differential equations. To this end, the particle distribution function is replaced by a number of discrete monodisperse fractions. The CORRAL-2 has an essentially empirical basis (processes not explicitely modelled, but their net effects accounted for). The physical processes taken into account in the codes are shown finally

  17. Comparison of physical chemical properties of powders and respirable aerosols of industrial mixed uranium and plutonium oxide fuels

    International Nuclear Information System (INIS)

    Eidson, A.F.

    1982-01-01

    Studies were performed to characterize physical and chemical properties which may be important in determining the metabolism of accidentally released, inhaled aerosols of industrial mixed uranium and plutonium oxide fuels and to compare the properties of bulk powders and the respirable fraction they include. X-ray diffraction measurements showed that analysis of mixed-oxide powders from four process steps served to characterize their respirable fractions. IR spectroscopy was useful as a method to detect organic binders that were not observed by X-ray diffraction methods. Both X-ray diffraction and IR spectroscopy methods can be used in combination to identify the sources of a complex aerosol that might be released from more than one fabrication step. Isotopic distributions in powders and aerosols showed that information important for radiation dose to tissue calculations or Pu lung burden estimates can be obtained by analysis of powders. (U.K.)

  18. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    Science.gov (United States)

    Healy, D. A.; Huffman, J. A.; O'Connor, D. J.; Pöhlker, C.; Pöschl, U.; Sodeau, J. R.

    2014-08-01

    Primary biological aerosol particles (PBAPs) can contribute significantly to the coarse particle burden in many environments. PBAPs can thus influence climate and precipitation systems as cloud nuclei and can spread disease to humans, animals, and plants. Measurement data and techniques for PBAPs in natural environments at high time- and size resolution are, however, sparse, and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in southwestern Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of a waveband integrated bioaerosol sensor (WIBS-4) with a ultraviolet aerodynamic particle sizer (UV-APS) and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behavior, with increased fluorescent bioparticle concentrations at night, when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each was correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.). The WIBS FL1 channel exhibited variable multimodal distributions turning into a broad featureless single mode after averaging, and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent

  19. Aerosol optical properties measurements by a CAPS single scattering albedo monitor: Comparisons between summer and winter in Beijing, China

    Science.gov (United States)

    Han, Tingting; Xu, Weiqi; Li, Jie; Freedman, Andrew; Zhao, Jian; Wang, Qingqing; Chen, Chen; Zhang, Yingjie; Wang, Zifa; Fu, Pingqing; Liu, Xingang; Sun, Yele

    2017-02-01

    Aerosol optical properties were measured in Beijing in summer and winter using a state-of-the-art cavity attenuated phase shift single scattering albedo monitor (CAPS PMssa) along with aerosol composition measurements by aerosol mass spectrometers and aethalometers. The SSA directly measured by the CAPS PMssa showed overall agreements with those derived from colocated measurements. However, substantial differences were observed during periods with low SSA values in both summer and winter, suggesting that interpretation of low SSA values needs to be cautious. The average (±σ) extinction coefficient (bext) and absorption coefficient (bap) were 336 (±343) Mm-1 and 44 (±41) Mm-1, respectively, during wintertime, which were approximately twice those observed in summer, while the average SSA was relatively similar, 0.86 (±0.06) and 0.85 (±0.04) in summer and winter, respectively. Further analysis showed that the variations in SSA can be approximately parameterized as a function of mass fraction of secondary particulate matter (fSPM), which is SSA = 0.74 + 0.19 × fSPM (fSPM > 0.3, r2 = 0.85). The contributions of aerosol species to extinction coefficients during the two seasons were also estimated. Our results showed that the light extinction was dominantly contributed by ammonium sulfate (30%) and secondary organic aerosol (22%) in summer, while organic aerosol was the largest contributor (51%) in winter. Consistently, SPM played the major role in visibility degradation in both seasons by contributing 70% of the total extinction.

  20. Columnar Aerosol Properties from Sun-and-star Photometry: Statistical Comparisons and Day-to-night Dynamic

    Science.gov (United States)

    Ramirez, Daniel Perez; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Alados-Arboledas, L.

    2012-01-01

    This work presents the first analysis of longterm correlative day-to-night columnar aerosol optical properties. The aim is to better understand columnar aerosol dynamic from ground-based observations, which are poorly studied until now. To this end we have used a combination of sun-and-star photometry measurements acquired in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) from 2007 to 2010. For the whole study period, mean aerosol optical depth (AOD) around 440 nm (+/-standard deviation) is 0.18 +/- 0.10 and 0.19 +/- 0.11 for daytime and nighttime, respectively, while the mean Angstr¨om exponent (alpha ) is 1.0 +/- 0.4 and 0.9 +/- 0.4 for daytime and nighttime. The ANOVA statistical tests reveal that there are no significant differences between AOD and obtained at daytime and those at nighttime. Additionally, the mean daytime values of AOD and obtained during this study period are coherent with the values obtained in the surrounding AERONET stations. On the other hand, AOD around 440 nm present evident seasonal patterns characterised by large values in summer (mean value of 0.20 +/- 0.10 both at daytime and nighttime) and low values in winter (mean value of 0.15 +/- 0.09 at daytime and 0.17 +/- 0.10 at nighttime). The Angstr¨om exponents also present seasonal patterns, but with low values in summer (mean values of 0.8 +/- 0.4 and 0.9 +/- 0.4 at dayand night-time) and relatively large values in winter (mean values of 1.2 +/- 0.4 and 1.0 +/- 0.3 at daytime and nighttime). These seasonal patterns are explained by the differences in the meteorological conditions and by the differences in the strength of the aerosol sources. To take more insight about the changes in aerosol particles between day and night, the spectral differences of the Angstrom exponent as function of the Angstr¨om exponent are also studied. These analyses reveal increases of the fine mode radius and of the fine mode contribution to AOD during nighttime, being more

  1. Comparison of UV irradiances from Aura/Ozone Monitoring Instrument (OMI) with Brewer measurements at El Arenosillo (Spain) - Part 2: Analysis of site aerosol influence

    Science.gov (United States)

    Cachorro, V. E.; Toledano, C.; Antón, M.; Berjón, A.; de Frutos, A.; Vilaplana, J. M.; Arola, A.; Krotkov, N. A.

    2010-12-01

    SSA and to 9.03% for variable SSA. Similar results were obtained for spectral irradiances at 305 nm, and 310 nm. Contrary to what was expected, the constant SSA approach has a greater bias reduction than variable SSA, but this is a reasonable result according to the discussion about the reliability of SSA values. Our results reflect the level of accuracy that may be reached at the present time in this type of comparison, which may be considered as satisfactory taking into account the remaining dependence on other factors. Nevertheless, improvements must be accomplished to determine reliable absorbing aerosol properties, which appear as a limiting factor for improving OMI retrievals.

  2. Interim Proposal for Molecular Beam Studies of Surfactants in Sulfuric Acid Aerosols: Comparisons Between Hydrocarbon and Fluorocarbon Alcohols

    National Research Council Canada - National Science Library

    Nathanson, Gilbert

    2003-01-01

    .... These processes include the acid-catalyzed reactions of HCI and HBr with CIONO2 (BrONO2) and HOCI (HOBr) to generate photoactive halogen molecules, particularly in colder regions of the stratosphere where they are more soluble in the water-rich aerosols...

  3. Aerosol Light Absorption and Scattering in Mexico City: Comparison With Las Vegas, NV, and Los Angeles, CA.

    Science.gov (United States)

    Paredes-Miranda, G.; Arnott, W. P.; Gaffney, J. S.; Marley, N. A.; Campbell, D.; Fujita, E.

    2007-12-01

    Aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The primary site in Mexico City was an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). Similar campaigns were held in Las Vegas, NV in January-February, 2003; and Los Angeles, CA at numerous sites during all seasons from 2003 through 2007. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The photoacoustic instrument (PAS) used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In Mexico City the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of Mexico City resulted in more direct solar radiation. Further insight on the meteorological connections and population dynamics will be discussed.

  4. Detailed Comparison of OC/EC Aerosol at an Urban and a Rural Czech Background Site during Summer and Winter

    Czech Academy of Sciences Publication Activity Database

    Vodička, Petr; Schwarz, Jaroslav; Cusack, Michael; Ždímal, Vladimír

    518-519, JUN 15 (2015), s. 424-433 ISSN 0048-9697 R&D Projects: GA ČR GAP209/11/1342 Institutional support: RVO:67985858 Keywords : carbonaceous aerosol * urban and rural background * organic carbon fractions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.976, year: 2015

  5. Results of an international comparison for the determination of radionuclide activity in bilberry material

    International Nuclear Information System (INIS)

    Wätjen, U.; Altzitzoglou, T.; Ceccatelli, A.; Dikmen, H.; Emteborg, H.; Ferreux, L.; Frechou, C.; La Rosa, J.; Luca, A.; Moreno, Y.; Oropesa, P.; Pierre, S.; Schmiedel, M.

    2012-01-01

    Radioactivity found in wild food products has assumed greater importance when assessing the total exposure of the population. For this reason, IRMM has been developing a reference material for the activity concentration of three radionuclides in bilberry samples. In order to characterise this new material, a CCRI(II) supplementary comparison was organised. The difficulties encountered in this comparison are discussed, in particular the efficiency calibration for volume sources of gamma-ray emitters, and comparison reference values for 137 Cs and 40 K are calculated. - Highlights: ► CCRI(II) supplementary comparison for Cs-137 and K-40 in bilberry matrix completed. ► Fundamentally different methods used to establish link to SI traceable standards and SIR. ► Variation of results higher than in CCRI(II) key comparisons. ► Comparison reference values will be robust property values of IRMM reference material. ► Certified reference material for radioactivity in food developed.

  6. Speciation of the major inorganic salts in atmospheric aerosols of Beijing, China: Measurements and comparison with model

    Science.gov (United States)

    Tang, Xiong; Zhang, Xiaoshan; Ci, Zhijia; Guo, Jia; Wang, Jiaqi

    2016-05-01

    In the winter and summer of 2013-2014, we used a sampling system, which consists of annular denuder, back-up filter and thermal desorption set-up, to measure the speciation of major inorganic salts in aerosols and the associated trace gases in Beijing. This sampling system can separate volatile ammonium salts (NH4NO3 and NH4Cl) from non-volatile ammonium salts ((NH4)2SO4), as well as the non-volatile nitrate and chloride. The measurement data was used as input of a thermodynamic equilibrium model (ISORROPIA II) to investigate the gas-aerosol equilibrium characteristics. Results show that (NH4)2SO4, NH4NO3 and NH4Cl were the major inorganic salts in aerosols and mainly existed in the fine particles. The sulfate, nitrate and chloride associated with crustal ions were also important in Beijing where mineral dust concentrations were high. About 19% of sulfate in winter and 11% of sulfate in summer were associated with crustal ions and originated from heterogeneous reactions or direct emissions. The non-volatile nitrate contributed about 33% and 15% of nitrate in winter and summer, respectively. Theoretical thermodynamic equilibrium calculations for NH4NO3 and NH4Cl suggest that the gaseous precursors were sufficient to form stable volatile ammonium salts in winter, whereas the internal mixing with sulfate and crustal species were important for the formation of volatile ammonium salts in summer. The results of the thermodynamic equilibrium model reasonably agreed with the measurements of aerosols and gases, but large discrepancy existed in predicting the speciation of inorganic ammonium salts. This indicates that the assumption on crustal species in the model was important for obtaining better understanding on gas-aerosol partitioning and improving the model prediction.

  7. Comparison of structural features of water-soluble organic matter from atmospheric aerosols with those of aquatic humic substances

    Science.gov (United States)

    Duarte, Regina M. B. O.; Santos, Eduarda B. H.; Pio, Casimiro A.; Duarte, Armando C.

    Elemental analysis, Fourier transform infrared coupled to attenuated total reflectance (FTIR-ATR) and solid-state cross polarization with magic angle spinning- 13C-nuclear magnetic resonance (CPMAS 13C NMR) spectroscopies were used to compare the chemical features of water-soluble organic compounds (WSOC) from atmospheric aerosols with those of aquatic humic and fulvic acids. The influence of different meteorological conditions on the structural composition of aerosol WSOC was also evaluated. Prior to the structural characterisation, the WSOC samples were separated into hydrophobic acids and hydrophilic acids fractions by using a XAD-8/XAD-4 isolation procedure. Results showed that WSOC hydrophobic acids are mostly aliphatic (40-62% of total NMR peak area), followed by oxygenated alkyls (15-21%) and carboxylic acid (5.4-13.4%) functional groups. Moreover, the aromatic content of aerosol WSOC samples collected between autumn and winter seasons is higher (˜18-19%) than that of samples collected during warmer periods (˜6-10%). The presence of aromatic signals typical of lignin-derived structures in samples collected during low-temperature conditions highlights the major contribution of wood burning processes in domestic fireplaces into the bulk chemical properties of WSOC from aerosols. According to our investigations, aerosol WSOC hydrophobic acids and aquatic fulvic and humic acids hold similar carbon functional groups; however, they differ in terms of the relative carbon distribution. Elemental analysis indicates that H and N contents of WSOC hydrophobic acids samples surpass those of aquatic fulvic and humic acids. In general, the obtained results suggest that WSOC hydrophobic acids have a higher aliphatic character and a lower degree of oxidation than those of standard fulvic and humic acids. The study here reported suggests that aquatic fulvic and humic acids may not be good models for WSOC from airborne particulate matter.

  8. Chemical Bonding and Structural Information of Black CarbonReference Materials and Individual Carbonaceous AtmosphericAerosols

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Rebecca J.; Tivanski, Alexei V.; Marten, Bryan D.; Gilles, Mary K.

    2007-04-25

    The carbon-to-oxygen ratios and graphitic nature of a rangeof black carbon standard reference materials (BC SRMs), high molecularmass humic-like substances (HULIS) and atmospheric particles are examinedusing scanning transmission X-ray microscopy (STXM) coupled with nearedge X-ray absorption fine structure (NEXAFS) spectroscopy. UsingSTXM/NEXAFS, individual particles with diameter>100 nm are studied,thus the diversity of atmospheric particles collected during a variety offield missions is assessed. Applying a semi-quantitative peak fittingmethod to the NEXAFS spectra enables a comparison of BC SRMs and HULIS toparticles originating from anthropogenic combustion and biomass burns,thus allowing determination of the suitability of these materials forrepresenting atmospheric particles. Anthropogenic combustion and biomassburn particles can be distinguished from one another using both chemicalbonding and structural ordering information. While anthropogeniccombustion particles are characterized by a high proportion ofaromatic-C, the presence of benzoquinone and are highly structurallyordered, biomass burn particles exhibit lower structural ordering, asmaller proportion of aromatic-C and contain a much higher proportion ofoxygenated functional groups.

  9. Aerosolization of fungi, (1→3)-β-D glucan, and endotoxin from flood-affected materials collected in New Orleans homes

    Science.gov (United States)

    Adhikari, Atin; Jung, Jaehee; Reponen, Tiina; Lewis, Jocelyn Suzanne; DeGrasse, Enjoli C.; Grimsley, L. Faye; Chew, Ginger L.; Grinshpun, Sergey A.

    2015-01-01

    Standing water and sediments remaining on flood-affected materials were the breeding ground for many microorganisms in flooded homes following Hurricane Katrina. The purpose of this laboratory study was to examine the aerosolization of culturable and total fungi, (1→3)-β-D glucan, and endotoxin from eight flood-affected floor and bedding materials collected in New Orleans homes, following Hurricane Katrina. Aerosolization was examined using the Fungal Spore Source Strength Tester (FSSST) connected to a BioSampler. Dust samples were collected by vacuuming. A two-stage cyclone sampler was used for size-selective analysis of aerosolized glucan and endotoxin. On average, levels of culturable fungi ranged from undetectable (lower limit = 8.3×104) to 2.6×105 CFU/m2; total fungi ranged from 2.07×105 to 1.6×106 spores/m2; (1→3)-β-D glucan and endotoxin were 2.0×103 – 2.9×104 ng/m2 and 7.0×102 – 9.3×104 EU/m2, respectively. The results showed that 5–15 min sampling is sufficient for detecting aerosolizable biocontaminants with the FSSST. Smaller particle size fractions (1.8 μm) fractions, which raises additional exposure concerns. Vacuuming was found to overestimate inhalation exposure risks by a factor of approximately 102 for (1→3)-β-D glucan and by 103 to 104 for endotoxin as detected by the FSSST. The information generated from this study is important with respect to restoration and rejuvenation of the flood-affected areas in New Orleans. We believe the findings will be significant during similar disasters in other regions of the world including major coastal floods from tsunamis. PMID:19201399

  10. Modeling of Solar Radiation Management: A Comparison of Simulations Using Reduced Solar Constant and Stratospheric Sulphate Aerosols

    Science.gov (United States)

    Bala, G.; Kalidindi, S.; Modak, A.; Caldeira, K.

    2014-12-01

    Several climate modelling studies in the past have used reduction in solar constant to simulate the climatic effects of Solar Radiation Management (SRM) geoengineering. This is most likely valid only for space-based mirrors/reflectors but not for SRM methods that rely on stratospheric aerosols. In this study, we use a climate model to evaluate the differences in climate response to SRM by uniform solar constant reduction and stratospheric aerosols. The experiments are designed such that global mean warming from a doubling of atmospheric CO2 concentration (2xCO2) is nearly cancelled in each case. In such a scenario, the residual climate effects are similar when important surface and tropospheric climate variables such as temperature and precipitation are considered. However, there are significant differences in stratospheric temperature response and diffuse and direct radiation reaching the surface. A difference of 1K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods, with warming in the aerosol scheme and a slight cooling for sunshades. While the global mean surface diffuse radiation increases by ~23% and direct radiation decreases by about 9% in the case of aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~1.0%) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 1.8 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 15.2% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~ 8%) and NPP (~3%) relative to 2xCO2, indicating the negligible effect of the fractional changes in direct/diffuse radiation on the overall plant productivity. Based on our modelling study, we conclude that the climate states produced by a

  11. Impacts of aerosol lead to natural ecosystems

    International Nuclear Information System (INIS)

    Murozumi, Masayo; Nakamura, Seiji; Yoshida, Katsumi

    1982-01-01

    Impacts of aerosol lead have changed the concentration and isotopic ratios of the element circulating in remote ecosystems in the Hidaka and Tarumae mountains. Concentrations of lead in successive each 10 years ring veneer of Cercidiphyllum Japonica show that amount of the element residing on the bark and supwood layers has increased by a factor of 2 or more in comparison with that of the core part. The isotopic ratios of lead in the basement rocks and soils under the ecosystems converge to a certain narrow spot along the isochron Iine of the element, and distinguish their geochronogical characteristics from other leads of different sources. In these ecosystems, however, the lead isotopic ratios of materials exposed to the atmosphere are similar to those of foreign and anthropogenic aerosol lead but are evidently dissimilar to those of the rocks and soils. Furthermore, the lead isotopic ratios in yearly ring veneers of Ceridiphyllum Japonica and Ostrya Japonica show a certain differentiation towards the bark from the core, i.e., an approach to those of anthropogenic aerosol lead from those of the basement rocks and soils, as listed in Table 7. The lead burden per hectare in these remote ecosystems has increased to 4 g by the impact of 2 g of aerosol lead. (author)

  12. Estimated SAGE II ozone mixing ratios in early 1993 and comparisons with Stratospheric Photochemistry, Aerosols and Dynamic Expedition measurements

    Science.gov (United States)

    Yue, G. K.; Veiga, R. E.; Poole, L. R.; Zawodny, J. M.; Proffitt, M. H.

    1994-01-01

    An empirical time-series model for estimating ozone mixing ratios based on Stratospheric Aerosols and Gas Experiment II (SAGE II) monthly mean ozone data for the period October 1984 through June 1991 has been developed. The modeling results for ozone mixing ratios in the 10- to 30- km region in early months of 1993 are presented. In situ ozone profiles obtained by a dual-beam UV-absorption ozone photometer during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) campaign, May 1-14, 1993, are compared with the model results. With the exception of two profiles at altitudes below 16 km, ozone mixing ratios derived by the model and measured by the ozone photometer are in relatively good agreement within their individual uncertainties. The identified discrepancies in the two profiles are discussed.

  13. 4STAR Sky-Scanning Retrievals of Aerosol Intensive Optical Properties from Multiple Field Campaigns with Detailed Comparisons of SSA Reported During SEAC4RS

    Science.gov (United States)

    Flynn, Connor; Dahlgren, R. P.; Dunagan, S.; Johnson, R.; Kacenelenbogen, M.; LeBlanc, S.; Livingston, J.; Redemann, J.; Schmid, B.; Segal Rozenhaimer, M.; hide

    2015-01-01

    The 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument combines airborne sun tracking capabilities of the Ames Airborne Tracking Sun Photometer (AATS-14) with AERONET-like sky-scanning capability and adds state-of-the-art fiber-coupled grating spectrometry to yield hyper spectral measurements of direct solar irradiance and angularly resolved sky radiance. The combination of sun-tracking and sky-scanning capability enables retrievals of wavelength-dependent aerosol optical depth (AOD), mode-resolved aerosol size distribution (SD), asphericity, and complex refractive index, and thus also the scattering phase function, asymmetry parameter, single-scattering albedo (SSA), and absorption aerosol optical thickness (AAOT).From 2012 to 2014 4STAR participated in four major field campaigns: the U.S. Dept. of Energy TCAP I II campaigns, and NASAs SEAC4RS and ARISE campaigns. Establishing a strong performance record, 4STAR operated successfully on all flights conducted during each of these campaigns. Sky radiance spectra from scans in either constant azimuth (principal plane) or constant zenith angle (almucantar) were interspersed with direct beam measurements during level legs. During SEAC4RS and ARISE, 4STAR airborne measurements were augmented with flight-level albedo from the collocated Shortwave Spectral Flux Radiometer (SSFR) providing improved specification of below-aircraft radiative conditions for the retrieval. Calibrated radiances and retrieved products will be presented with particular emphasis on detailed comparisons of ambient SSA retrievals and measurements during SEAC4RS from 4STAR, AERONET, HSRL2, and from in situ measurements.

  14. MAX-DOAS observations of aerosols, formaldehyde and nitrogen dioxide in the Beijing area: comparison of two profile retrieval approaches

    Directory of Open Access Journals (Sweden)

    T. Vlemmix

    2015-02-01

    Full Text Available A 4-year data set of MAX-DOAS observations in the Beijing area (2008–2012 is analysed with a focus on NO2, HCHO and aerosols. Two very different retrieval methods are applied. Method A describes the tropospheric profile with 13 layers and makes use of the optimal estimation method. Method B uses 2–4 parameters to describe the tropospheric profile and an inversion based on a least-squares fit. For each constituent (NO2, HCHO and aerosols the retrieval outcomes are compared in terms of tropospheric column densities, surface concentrations and "characteristic profile heights" (i.e. the height below which 75% of the vertically integrated tropospheric column density resides. We find best agreement between the two methods for tropospheric NO2 column densities, with a standard deviation of relative differences below 10%, a correlation of 0.99 and a linear regression with a slope of 1.03. For tropospheric HCHO column densities we find a similar slope, but also a systematic bias of almost 10% which is likely related to differences in profile height. Aerosol optical depths (AODs retrieved with method B are 20% high compared to method A. They are more in agreement with AERONET measurements, which are on average only 5% lower, however with considerable relative differences (standard deviation ~ 25%. With respect to near-surface volume mixing ratios and aerosol extinction we find considerably larger relative differences: 10 ± 30, −23 ± 28 and −8 ± 33% for aerosols, HCHO and NO2 respectively. The frequency distributions of these near-surface concentrations show however a quite good agreement, and this indicates that near-surface concentrations derived from MAX-DOAS are certainly useful in a climatological sense. A major difference between the two methods is the dynamic range of retrieved characteristic profile heights which is larger for method B than for method A. This effect is most pronounced for HCHO, where retrieved profile shapes with method

  15. Technical committee meeting on aerosol formation, vapour deposits and sodium vapour trapping. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1977-01-01

    The papers presented at the LMFBR meeting on aerosol formation covered the following four main topics: theoretical studies on aerosol behaviour and comparison with experimental results; techniques for measurement of aerosols; techniques for trapping sodium vapour and aerosols in gas circuits; design of components having to cope with aerosol deposits. The resulting summaries, conclusions and recommendations which were were agreed upon are presented.

  16. Technical committee meeting on aerosol formation, vapour deposits and sodium vapour trapping. Summary report

    International Nuclear Information System (INIS)

    1977-01-01

    The papers presented at the LMFBR meeting on aerosol formation covered the following four main topics: theoretical studies on aerosol behaviour and comparison with experimental results; techniques for measurement of aerosols; techniques for trapping sodium vapour and aerosols in gas circuits; design of components having to cope with aerosol deposits. The resulting summaries, conclusions and recommendations which were were agreed upon are presented

  17. Stratospheric aerosols

    International Nuclear Information System (INIS)

    Rosen, J.; Ivanov, V.A.

    1993-01-01

    Stratospheric aerosol measurements can provide both spatial and temporal data of sufficient resolution to be of use in climate models. Relatively recent results from a wide range of instrument techniques for measuring stratospheric aerosol parameters are described. Such techniques include impactor sampling, lidar system sensing, filter sampling, photoelectric particle counting, satellite extinction-sensing using the sun as a source, and optical depth probing, at sites mainly removed from tropospheric aerosol sources. Some of these techniques have also had correlative and intercomparison studies. The main methods for determining the vertical profiles of stratospheric aerosols are outlined: lidar extinction measurements from satellites; impactor measurements from balloons and aircraft; and photoelectric particle counter measurements from balloons, aircraft, and rockets. The conversion of the lidar backscatter to stratospheric aerosol mass loading is referred to. Absolute measurements of total solar extinction from satellite orbits can be used to extract the aerosol extinction, and several examples of vertical profiles of extinction obtained with the SAGE satellite are given. Stratospheric mass loading can be inferred from extinction using approximate linear relationships but under restrictive conditions. Impactor sampling is essentially the only method in which the physical nature of the stratospheric aerosol is observed visually. Vertical profiles of stratospheric aerosol number concentration using impactor data are presented. Typical profiles using a dual-size-range photoelectric dustsonde particle counter are given for volcanically disturbed and inactive periods. Some measurements of the global distribution of stratospheric aerosols are also presented. Volatility measurements are described, indicating that stratospheric aerosols are composed primarily of about 75% sulfuric acid and 25% water

  18. Qualitative comparisons of fusion reactor materials for waste handling and disposal

    International Nuclear Information System (INIS)

    Maninger, R.C.

    1985-01-01

    The activation of five structural materials and seven coolant/breeder/multiplier materials in a common reference neutron environment was calculated with the FORIG activation code. The reference environment was the neutron flux and spectrum at the first wall of the mirror advanced reactor study (MARS) reactor. Qualitative comparison of these activated materials were made with respect to worker protection requirements for gamma radiation in handling the materials and with respect to their classifications for near-surface disposal of radioactive waste

  19. Comparison of Biochars Characteristics from Different Raw Materials

    OpenAIRE

    SUN Tao; ZHU Xin-ping; LI Dian-peng; GU Zhu-yu; ZHANG Jia-xi; JIA Hong-tao

    2017-01-01

    Biochar is the carbon-rich product from biomass under limited supply of oxygen. Biochar has been well recognized in enhancing terrestrial carbon sequestration and greenhouse gas mitigation as well as in improving soil fertility and plant productivity. To explore the differences of biochars produced from different raw materials, six biochar samples made from alfalfa straw, wheat straw, cotton straw, grape vines, sludge and lignite were selected as test material. Qualitative and quantitative an...

  20. Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

    Science.gov (United States)

    Saturno, Jorge; Pöhlker, Christopher; Massabò, Dario; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditas, Florian; Hrabě de Angelis, Isabella; Morán-Zuloaga, Daniel; Pöhlker, Mira L.; Rizzo, Luciana V.; Walter, David; Wang, Qiaoqiao; Artaxo, Paulo; Prati, Paolo; Andreae, Meinrat O.

    2017-08-01

    Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP) data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA), which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June-September 2014). The mean absorption coefficient (at 637 nm) during this period was 1.8 ± 2.1 Mm-1, with a maximum of 15.9 Mm-1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS) retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

  1. Comparison of materials accounting in conversion and coconversion processes

    International Nuclear Information System (INIS)

    Dayem, H.A.

    1981-01-01

    Materials accounting systems performances are compared for plutonium nitrate-to-oxide conversion [Oxalate (III)] and uranium-plutonium coconversion (Coprecal and modified Coprecal). These processes have the same design basis plutonium throughput and achieve this throughput in parallel operating lines. However, the process line configurations differ. In comparing the materials loss detection sensitivities for the three processes, we find better materials loss detection sensitivity for the Oxalate (III) process than for either of the two Coprecal processes, better single-balance detection sensitivity for the original Coprecal than for the modified Coprecal, and better long-term detection sensitivity (> 1d) for the modified Coprecal than for the original Coprecal. Sensivity differences result from differences in in-process inventories, feeding arrangements, and scrap generation

  2. Comparison of two different dust emission mechanisms over the Horqin Sandy Land area: Aerosols contribution and size distributions

    Science.gov (United States)

    Ju, Tingting; Li, Xiaolan; Zhang, Hongsheng; Cai, Xuhui; Song, Yu

    2018-03-01

    Dust aerosols (PM10) emission fluxes due to convective turbulent dust emissions (CTDE) and saltation-bombardment and/or aggregation-disintegration dust emissions (SADE) events were comparatively studied using the data obtained from the Naiman station over the Horqin Sandy Land area in Inner Mongolia, China from 2011 to 2015. The annual cumulative dust fluxes released by CTDE events was about one third of that by SADE events, with the order of 103∼104 μg m-2 s-1. The particle size distributions (PSDs) with diameter between 0.1 and 20 μm during CTDE and SADE events over the Horqin Sandy Land area were simulated based on the fragmentation theory, respectively. The results indicated that an improved equation based on fragmentation theory could be applied to describe the PSDs over the Horqin site which may be because the scale-invariant fragmentation theory mainly explains the PSDs of free dust particles on the surface, which differ from the PSDs of suspend airborne dust and the improved equation was more applicable to the PSDs of SADE events because the dust emission mechanism of SADE are saltation bombardment and aggregation disintegration. The number-related mean aerosol diameters (DN) barely varied under different friction velocity (u*) for SADE events, while the volume-related mean aerosol diameters (DV) changed distinctly with the change of u*. For CTDE events, the DN and DV had no obvious relationship with the change of u* because the dominating influence factor during CTDE event was thermal convection rather than u*. The mass-related PSDs usually exhibited a peak between 0.45 and 0.70 μm during SADE events, while for CTDE events there was a wide peak in the range of 0.10 0.70 μm. The results suggest that DN should be not be recommended as an individual parameter to describe the PSDs. The mass-related PSDs can effectively distinguish the SADE and CTDE events.

  3. Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

    Directory of Open Access Journals (Sweden)

    T. Liu

    2018-04-01

    Full Text Available The formation of secondary organic aerosol (SOA has been widely studied in the presence of dry seed particles at low relative humidity (RH. At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm−3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm−3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m ∕ z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS, indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory

  4. Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

    Science.gov (United States)

    Liu, Tengyu; Huang, Dan Dan; Li, Zijun; Liu, Qianyun; Chan, ManNin; Chan, Chak K.

    2018-04-01

    The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm-3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm-3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m / z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS), indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory experiments conducted with a wide variety of SOA precursors

  5. A comparison of microhardness of indirect composite restorative materials

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clóvis; Bottino, Marco Cícero

    2003-01-01

    The purpose of this study was to compare the microhardness of four indirect composite resins. Forty cylindrical samples were prepared according to the manufacturer’s recommendations using a Teflon mold. Ten specimens were produced from each tested material, constituting four groups (n=10) as foll...... esthetics and adequate mechanical properties may be considered as substitutes of natural teeth....

  6. A Comparison of implant impression precision: Different materials and techniques

    Science.gov (United States)

    Tabesh, Mahtab; Alikhasi, Marzieh

    2018-01-01

    Background Precision of implant impressions is a prerequisite for long-term success of implant supported prostheses. Impression materials and impression techniques are two important factors that impression precision relies on. Material and Methods A model of edentulous maxilla containing four implants inserted by All-on-4 guide was constructed. Seventy two impressions using polyether (PE), polyvinyl siloxane (PVS), and vinyl siloxanether (VSE) materials with direct and indirect techniques were made (n=12). Coordinates of implants in casts were measured using coordinate measuring machine (CMM). Data were analyzed with ANOVA; t-test and Tukey test were used for post hoc. Results With two-way ANOVA, mean values of linear displacements of implants were significantly different among materials and techniques. One-way ANOVA and Tukey showed significant difference between PE and VSE (P=0.019), PE and PVS (P=0.002) in direct technique, and between PVS and PE (Pimpression of implants, PE is recommended for direct technique while PE and VSE are recommended for indirect technique. Recommended technique for VSE is either direct or indirect; and for PE and PVS is direct. Key words:Polyvinyl siloxane, polyether, vinyl siloxanether, direct technique, indirect technique, All-on-4, coordinate measuring machine. PMID:29670733

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

    Energy Technology Data Exchange (ETDEWEB)

    Dyment, J.

    1963-11-15

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

  8. Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

    Directory of Open Access Journals (Sweden)

    J. Saturno

    2017-08-01

    Full Text Available Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA, which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June–September 2014. The mean absorption coefficient (at 637 nm during this period was 1.8 ± 2.1 Mm−1, with a maximum of 15.9 Mm−1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

  9. Comparison of different homogenization approaches for elastic–viscoplastic materials

    International Nuclear Information System (INIS)

    Mercier, S; Molinari, A; Berbenni, S; Berveiller, M

    2012-01-01

    Homogenization of linear viscoelastic and non-linear viscoplastic composite materials is considered in this paper. First, we compare two homogenization schemes based on the Mori–Tanaka method coupled with the additive interaction (AI) law proposed by Molinari et al (1997 Mech. Mater. 26 43–62) or coupled with a concentration law based on translated fields (TF) originally proposed for the self-consistent scheme by Paquin et al (1999 Arch. Appl. Mech. 69 14–35). These methods are also evaluated against (i) full-field calculations of the literature based on the finite element method and on fast Fourier transform, (ii) available analytical exact solutions obtained in linear viscoelasticity and (iii) homogenization methods based on variational approaches. Developments of the AI model are obtained for linear and non-linear material responses while results for the TF method are shown for the linear case. Various configurations are considered: spherical inclusions, aligned fibers, hard and soft inclusions, large material contrasts between phases, volume-preserving versus dilatant anelastic flow, non-monotonic loading. The agreement between the AI and TF methods is excellent and the correlation with full field calculations is in general of quite good quality (with some exceptions for non-linear composites with a large volume fraction of very soft inclusions for which a discrepancy of about 15% was found for macroscopic stress). Description of the material behavior with internal variables can be accounted for with the AI and TF approaches and therefore complex loadings can be easily handled in contrast with most hereditary approaches. (paper)

  10. Experimental relationship between the specific resistance of a HEPA [High Efficiency Particulate Air] filter and particle diameters of different aerosol materials

    International Nuclear Information System (INIS)

    Novick, V.J.; Monson, P.R.; Ellison, P.E.

    1990-01-01

    The increase in pressure drop across a HEPA filter has been measured as a function of the particle mass loading using two materials with different particle morphologies. The HEPA filter media chosen, is identical to the filter media used in the Airborne Activity Confinement System (AACS) on the Savannah River Reactors. The velocity through the test filter media was the same as the velocity through the AACS media, under normal operating flow conditions. Sodium Chloride challenge particles were generated using an atomizer, resulting in regularly shaped crystalline forms. Ammonium chloride aerosols were formed from the gas phase reaction of HCl and NH 4 OH vapors resulting in irregular agglomerates. In both cases, the generation conditions were adjusted to provide several different particle size distributions. For each particle size distribution, the mass of material loaded per unit area of filter per unit pressure drop for a given filtration velocity (1/Specific resistance) was measured. Theoretical considerations in the most widely accepted filter cake model predict that the mass per unit area and per unit pressure drop should increase with the particle density times the particle diameter squared. However, these test results indicate that the increase in the mass loaded per unit area per unit pressure drop, for both materials, can be better described by plotting the specific resistance divided by the particle density as an inverse function of the particle density times the particle diameter squared. 9 refs., 7 figs

  11. Direct measurement of aerosol shape factors

    International Nuclear Information System (INIS)

    Zeller, W.

    1983-12-01

    The dynamic shape factor whereas the coagulation shape factor is an average over the total examined size range. The experiments have shown that the results of experiments with a certain aerosol system cannot be transferred to other aerosol systems without further consideration. The outer shape of particles of a certain size depends on the specific properties of the material as well as on the experimental conditions during the aerosol generation. For both aerosol systems examined the mean dynamic shape factor, averaged over the total examined size range, agrees roughly with the coagulation shape factor. (Description of aerosol centrifuge and of differential mobility analyzer). (orig./HP) [de

  12. A comparison of chemical reference materials for solution calorimeters.

    Science.gov (United States)

    Ramos, Rita; Gaisford, Simon; Buckton, Graham; Royall, Paul G; Yff, Barbara T S; O'Neill, Michael A A

    2005-08-11

    Solution calorimeters are based on semi-adiabatic or isothermal heat-conduction principles and differ in the way they record data. They also have different measuring sensitivities and require different quantities of solute and solvent. As such, the choice of chemical test substance is not straightforward. Usually the dilution of KCl is recommended; it is possible to purchase a reference sample of KCl that has a certified enthalpy of solution and this standard material is usually used to test semi-adiabatic instruments. Here, we review the suitability of a range of chemical test substances (KCl, sucrose and Tris) for an isothermal heat-conduction solution calorimeter. It was found that KCl was not the best test material because its relatively high enthalpy of solution (DeltasolH) necessitated the use of small samples (2 mg), resulting in a relatively large standard deviation (sigman-1) in the values recorded (DeltasolH=17.14+/-0.49 kJ mol-1); furthermore, KCl data must be corrected to account for the effect of dilution, although the correction was found to be small (0.07 kJ mol-1) under the experimental conditions employed here. Sucrose appears to be a much more robust test material for isothermal heat-conduction instruments because its lower enthalpy of solution allows the use of much larger samples (20 mg), which minimises experimental errors. The DeltasolH value returned (6.14+/-0.08 kJ mol-1) is in excellent agreement with the literature. It is also cheap, readily available and requires minimal preparation although its widespread use would require the preparation of a certified reference sample.

  13. Comparison of material irradiation conditions for fusion, spallation, stripping and fission neutron sources

    International Nuclear Information System (INIS)

    Vladimirov, P.; Moeslang, A.

    2004-01-01

    Selection and development of materials capable of sustaining irradiation conditions expected for a future fusion power reactor remain a big challenge for material scientists. Design of other nuclear facilities either in support of the fusion materials testing program or for other scientific purposes presents a similar problem of irradiation resistant material development. The present study is devoted to an evaluation of the irradiation conditions for IFMIF, ESS, XADS, DEMO and typical fission reactors to provide a basis for comparison of the data obtained for different material investigation programs. The results obtained confirm that no facility, except IFMIF, could fit all user requirements imposed for a facility for simulation of the fusion irradiation conditions

  14. Comparison of differences between ports for radioactive material transport

    International Nuclear Information System (INIS)

    Massey, C.D.; Wheeler, T.A.; Yoshimura, H.R.

    1994-01-01

    Recent controversy and litigation over the import/export of radioactive materials into and out of the United States via United States ports has centered on differences between ports, especially differences in surrounding population densities, and also whether reliance on one or a few ports poses unacceptable risks for these ports and the surrounding populations. This study examines the results of risk analyses from several recent environmental assessments dealing with import/export of various types of radioactive materials ranging from uranium hexafluoride to spent nuclear fuel. Since an intermodal transfer is always involved, the maritime and intermodal transportation is broken down into its component activities and segments; each is determined separately. The results indicate that most of the potential exposure occurs during routine handling of packages during intermodal transfer. Since handling of containerized cargo is highly standardized at ports around the world, differences between ports are of secondary importance. The risks associated with any overland transport from port to inland destination are primarily a function of distance for a given package type

  15. Characterization of aerosols produced in cutting steel components and concrete structures by means of a laser beam

    International Nuclear Information System (INIS)

    Tarroni, G.; Melandri, C.; Zaiacomo, T. de; Lombard, C.C.; Formignani, M.

    1986-01-01

    The technique of cutting based on the use of a laser beam is studied as a possible method in nuclear plant dismantling (OECD, 1982). The technique implies a relevant problem of contamination due to high aerosol production. Tests have been carried out to characterize the aerosol produced in cutting steel and concrete in terms of size spectrum, electric charge and chemical composition in comparison with bulk material composition. The high temperature value locally reached in the cutting zone causes material vaporization with emission of very fine primary particles. In such conditions aerosol coagulation is very fast (it occurs in less than 1s) and leads to aggregates. Research has been aimed at finding the characteristics of the aerosol removable from the cutting zone by ventilation and evaluating the morphology of the particles that diffuse at approximately 50 cm from the generation point, or settle on the cutting-box base. (author)

  16. Blanket materials for fusion reactors: comparisons of thermochemical performance

    International Nuclear Information System (INIS)

    Johnson, C.E.; Fischer, A.K.; Tetenbaum, M.

    1984-01-01

    Thermodynamic calculations have been made to predict the thermochemical performance of the fusion reactor breeder materials, Li 2 O, LiAlO 2 , and Li 4 SiO 4 in the temperature range 900 to 1300 0 K and in the oxygen activity range 10 -25 to 10 -5 . Except for a portion of these ranges, the performance of LiAlO 2 is predicted to be better than that of Li 2 O and Li 4 SiO 4 . The protium purge technique for enhancing tritium release is explored for the Li 2 O system; it appears advantageous at higher temperatures but should be used cautiously at lower temperatures. Oxygen activity is an important variable in these systems and must be considered in executing and interpreting measurements on rates of tritium release, the form of released tritium, diffusion of tritiated species and their identities, retention of tritium in the condensed phase, and solubility of hydrogen isotope gases

  17. Comparison of Different Wood Species as Raw Materials for Bioenergy

    Directory of Open Access Journals (Sweden)

    Bojana Klašnja

    2013-12-01

    Full Text Available Background and Purpose: Most projections of the global energy use predict that biomass will be an important component of primary energy sources in the coming decades. Short rotation plantations have the potential to become an important source of renewable energy in Europe because of the high biomass yields, a good combustion quality as solid fuel, ecological advantages and comparatively low biomass production costs. Materials and Methods: In this study, the wood of black locust Robinia pseudoacacia, white willow Salix alba L., poplars Populus deltoides and Populus x euramericana cl.I-214, aged eight years were examined. Immediately after the felling, sample discs were taken to assess moisture content, ash content, the width of growth rings, wood densities and calorific values, according to the standard methodology. Results:The mean values of willow, poplar and black locust wood density were 341 kg/m3, 336 kg/m3 and 602 kg/m3,respectively. The average heating values of willow poplar and black locust wood were 18.599 MJ/kg, 18.564 MJ/kg and 21.196 MJ/kg, respectively. The FVI index (average values was higher for black locust (17.186 than for poplar and willow clones, which were similar: 11.312 and 11.422 respectively. Conclusions: Black locust wood with a higher density, calorific value and ash content compared to poplar and willow wood proved to be a more suitable raw material as RES. However, it is very important, from the aspect of the application of wood of these tree species as RES, to also consider the influence of the biomass yield per unit area of the plantations established as “energy plantations”.

  18. Use of an excess variance approach for the certification of reference materials by interlaboratory comparison

    International Nuclear Information System (INIS)

    Crozet, M.; Rigaux, C.; Roudil, D.; Tuffery, B.; Ruas, A.; Desenfant, M.

    2014-01-01

    In the nuclear field, the accuracy and comparability of analytical results are crucial to insure correct accountancy, good process control and safe operational conditions. All of these require reliable measurements based on reference materials whose certified values must be obtained by robust metrological approaches according to the requirements of ISO guides 34 and 35. The data processing of the characterization step is one of the key steps of a reference material production process. Among several methods, the use of interlaboratory comparison results for reference material certification is very common. The DerSimonian and Laird excess variance approach, described and implemented in this paper, is a simple and efficient method for the data processing of interlaboratory comparison results for reference material certification. By taking into account not only the laboratory uncertainties but also the spread of the individual results into the calculation of the weighted mean, this approach minimizes the risk to get biased certified values in the case where one or several laboratories either underestimate their measurement uncertainties or do not identify all measurement biases. This statistical method has been applied to a new CETAMA plutonium reference material certified by interlaboratory comparison and has been compared to the classical weighted mean approach described in ISO Guide 35. This paper shows the benefits of using an 'excess variance' approach for the certification of reference material by interlaboratory comparison. (authors)

  19. Comparison of Biochars Characteristics from Different Raw Materials

    Directory of Open Access Journals (Sweden)

    SUN Tao

    2017-10-01

    Full Text Available Biochar is the carbon-rich product from biomass under limited supply of oxygen. Biochar has been well recognized in enhancing terrestrial carbon sequestration and greenhouse gas mitigation as well as in improving soil fertility and plant productivity. To explore the differences of biochars produced from different raw materials, six biochar samples made from alfalfa straw, wheat straw, cotton straw, grape vines, sludge and lignite were selected as test material. Qualitative and quantitative analysis by fourier transform infrared spectroscopy(FTIR and Boehm titration were used to determine the amount of the surface functional groups of biochars. Meanwhile the scanning electron microscopy(SEM was used to characterize the surface morphology of biochar samples. In addition, the basic physicochemical characteristics of biochar samples, such as pH value, organic carbon content and cation exchange capacity were also determined. The results showed that all of the biochar were alkaline except the sludge biochar was acidic. The organic carbon content of alfalfa biochar was the highest(588.43 g·kg-1 and sludge biochar was the lowest(168.17 g·kg-1. Furthermore, the rank of cation exchange capacity was alfalfa straw biochar, cotton straw biochar > grape vine biochar > wheat straw biochar > sludge biochar > lignite biochar. FTIR spectrum showed that there were the aromatic hydrocarbon and the oxygen group on the surface of biochar and the structure of biochar was mainly based on the aromatic rings skeleton. The total functional groups content of alfalfa straw biochar was the highest, but that of sludge biochar was the lowest. The SEM results showed that there were obvious pore structure on the surface of plant-based biochar, but none on the surface of mineral-based biochar. Alfalfa straw biochar, wheat straw biochar, cotton straw biochar and grape vine biochar can be applied to improve farmland soil quality and increase soil fertility, and lignite biochar

  20. Comparison of computer codes relative to the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

    International Nuclear Information System (INIS)

    Fermandjian, J.; Bunz, H.; Dunbar, I.; Gauvain, J.; Ricchena, R.

    1986-01-01

    The present study concerns a comparative exercise, performed within the framework of the Commission of the European Communities, of the computer codes (AEROSIM-M, UK; AEROSOLS/B1, France; CORRAL-2, CEC and NAUA Mod5, Germany) used in order to assess the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR. Topics considered in this paper include aerosols, containment buildings, reactor safety, fission product release, reactor cores, meltdown, and monitoring

  1. Comparisons of processes and performance of SSC-VQP material

    International Nuclear Information System (INIS)

    Seuntjens, J.M.; Clark, F.Y.; Erdmann, M.J.; Coleman, E.S.; Jones, B.A.

    1994-01-01

    The Superconducting Super Collider's (SSC) cable Vendor Qualification Program (VQP) will end in FY 1993. At the time of this writing, all 8 vendors involved in this program have demonstrated capability to fabricate conductor which meets SSC specifications. The magnet vendors have hard choices to make in calendar year 1993 in deciding which cable vendors will make the production cable. It is well accepted that because of requirements of magnet uniformity, that only one vendor will be chosen for dipole Inner cable, one vendor for dipole Outer cable, and one vendor for quadrupole Outer cable. The production quantities are nominally 500, 500, and 200 metric tonnes, respectively. Among the many deciding factors are a technically sound production process, process control, and production quantity capability of each cable vendor. Qualified vendors will have proven their technical process and process control is adequate for production quantities. This paper is part of ongoing effort to provide technical information for the magnet vendor's decision making process. Some of the Phase IB process data is summarized as well as results of a portion of the materials characterization performed at the SSC Laboratory. Key process and final product parameters for each cable vendor are compared without identifying specific vendor's process detail

  2. Comparisons of processes and performance of SSC-VQP material

    International Nuclear Information System (INIS)

    Seuntjens, J.; Clark, F.; Erdmann, M.; Coleman, E.; Jones, B.

    1993-05-01

    The Superconducting Super Collider's (SSC) cable Vendor Qualification Program (VQP) will end in FY 1993. At the time of this writing, all 8 vendors involved in this program have demonstrated capability to fabricate conductor which meets SSC specifications. The magnet vendors have hard choices to make in calendar year 1993 in deciding which cable vendors will make the production cable. It is well accepted that because of requirements of magnet uniformity, that only one vendor will be chosen for dipole Inner cable, one vendor for dipole Outer cable, and one vendor for quadrupole Outer cable. The production quantities are nominally 500, 500, and 200 metric tonnes, respectively. Among the many deciding factors are a technically sound production process, process control, and production quantity capability of each cable vendor. Qualified vendors will have proven their technical process and process control is adequate for production quantities. This paper is part of ongoing effort to provide technical information for the magnet vendor's decision making process. Some of the Phase IB process data is summarized and well as results of a portion of the materials characterization performed at the SSC Laboratory. Key process and final product parameters for each cable vendor are compared without identifying specific vendor's process detail

  3. Comparison of ready biodegradation estimation methods for fragrance materials.

    Science.gov (United States)

    Boethling, Robert

    2014-11-01

    Biodegradability is fundamental to the assessment of environmental exposure and risk from organic chemicals. Predictive models can be used to pursue both regulatory and chemical design (green chemistry) objectives, which are most effectively met when models are easy to use and available free of charge. The objective of this work was to evaluate no-cost estimation programs with respect to prediction of ready biodegradability. Fragrance materials, which are structurally diverse and have significant exposure potential, were used for this purpose. Using a database of 222 fragrance compounds with measured ready biodegradability, 10 models were compared on the basis of overall accuracy, sensitivity, specificity, and Matthews correlation coefficient (MCC), a measure of quality for binary classification. The 10 models were VEGA© Non-Interactive Client, START (Toxtree©), Biowin©1-6, and two models based on inductive machine learning. Applicability domain (AD) was also considered. Overall accuracy was ca. 70% and varied little over all models, but sensitivity, specificity and MCC showed wider variation. Based on MCC, the best models for fragrance compounds were Biowin6, VEGA and Biowin3. VEGA performance was slightly better for the 0.8). However, removing compounds with one and only one quaternary carbon yielded similar improvement in predictivity for VEGA, START, and Biowin3/6, with a smaller penalty in reduced coverage. Of the nine compounds for which the eight models (VEGA, START, Biowin1-6) all disagreed with the measured value, measured analog data were available for seven, and all supported the predicted value. VEGA, Biowin3 and Biowin6 are judged suitable for ready biodegradability screening of fragrance compounds. Published by Elsevier B.V.

  4. PIXE and ICP-AES comparison in evaluating the efficiency of metal extraction and analysis in aerosol samples

    Energy Technology Data Exchange (ETDEWEB)

    Rugi, F.; Becagli, S.; Ghedini, C.; Marconi, M.; Severi, M.; Traversi, R.; Udisti, R. [Dep. of Chemistry, University of Florence, Sesto F.no (Fl) (Italy); Calzolai, G.; Chiari, M.; Lucarelli, F.; Nava, S. [Dep. of Physics and Astronomy , University of Florence and INFN, Sesto F. no (Fl) (Italy)

    2013-07-01

    Full text: A recent EU regulation (EN 149022005) requests the quantification of selected metals in the atmospheric particulate by mineralization with H{sub 2}0{sub 2} and HN0{sub 3} in microwave oven.This method might possibly conflict with the determination of the total metal content. In fact, the more the aerosol is enriched in crustal elements the more the difference in the two methods are expected, since the H{sub 2}0{sub 2}+ HN0{sub 3}, extraction is not reliable for metals in silicate form. In order to evaluate the extracted fraction, PIXE and ICP-AES measurements were carried out on the two halves of a series of PM10 and PM2.5 samples collected on Teflon filters in an urban site in the surrounding of Florence (Italy). An ICP-AES (Inductively Coupled Plasma -Atomic Emission Spectroscopy) method was optimized by an ultrasound nebuliser (CETAC 5000 AT+), in order to improve reproducibility and detection limit. In these conditions, it was possible quantifying AI, As, Cr, Cu, Fe, Mn, Ni, Pb and Vatsub-ppb levels. PIXE analysis using the external beam set-up at LABEC and a 3 MeV proton beam was carried out in order to measure the total elemental content of the metals. By comparing the ICP-AES and the PIXE results, a preliminary evaluation of the efficiency of the H{sub 2}0{sub 2} and HN0{sub 3} extraction method was performed. The obtained results (the mean values for the ICP-AES/PIXE ratio are reported in Table 1) show that the extraction procedure following the EN 14902 directive allows quantitative recoveries (80-120%, including the analytical uncertainties)for the majority of the analysed metals, especially for those mainly emitted by anthropic sources. This result points out that anthropic metals are present in the atmosphere as relatively available species (free metals, labile complexes, carbonates, oxides). On the contrary, lower recoveries were obtained for AI (mean value around 75%), a metal that has a relevant crustal fraction. Percentage of recovery of

  5. The fifth Finnish national aerosol symposium

    International Nuclear Information System (INIS)

    Mikkanen, P.; Haemeri, K.; Kauppinen, E.

    1993-01-01

    The Fifth Finnish Aerosol Symposium was held June 1-3, 1993. Symposium is jointly organized by FAAR, Aerosol Technology Group of Technical Research Centre of Finland and Helsinki University, Department of Physics. Aerosols, the suspensions of solid and liquid particles and gases, are receiving increasing importance in many areas of science and technology. These include industrial hygiene, ambient and indoor air pollution, pollution control technologies, cloud physics, nuclear safety engineering, combustion science and engineering, clean manufacturing technologies and material processing. The importance of aerosol issues during the development of advanced fuel conversion and material processing technologies can be realized when looking at the numerous papers presented on these topics at the Symposium

  6. Wintertime organic and inorganic aerosols in Lanzhou, China: sources, processes, and comparison with the results during summer

    Directory of Open Access Journals (Sweden)

    J. Xu

    2016-12-01

    Full Text Available Lanzhou, which is located in a steep alpine valley in western China, is one of the most polluted cities in China during the wintertime. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, a seven-wavelength aethalometer, and a scanning mobility particle sizer (SMPS were deployed during 10 January to 4 February 2014 to study the mass concentrations, chemical processes, and sources of submicrometer particulate matter (PM1. The average PM1 concentration during this study was 57.3 µg m−3 (ranging from 2.1 to 229.7 µg m−3 for hourly averages, with organic aerosol (OA accounting for 51.2 %, followed by nitrate (16.5 %, sulfate (12.5 %, ammonium (10.3 %, black carbon (BC, 6.4 %, and chloride (3.0 %. The mass concentration of PM1 during winter was more than twice the average value observed at the same site in summer 2012 (24.5 µg m−3, but the mass fraction of OA was similar in the two seasons. Nitrate contributed a significantly higher fraction to the PM1 mass in winter than summer (16.5 % vs. 10 %, largely due to more favored partitioning to the particle phase at low air temperature. The mass fractions of both OA and nitrate increased by  ∼  5 % (47 to 52 for OA and 13 to 18 % for nitrate with the increase of the total PM1 mass loading, while the average sulfate fraction decreased by 6 % (17 to 11 %, indicating the importance of OA and nitrate for the heavy air pollution events in Lanzhou. The size distributions of OA, nitrate, sulfate, ammonium, and chloride all peaked at  ∼  500 nm, with OA being slightly broader, suggesting that aerosol particles were internally mixed during winter, likely due to frequently calm and stagnant air conditions during wintertime in Lanzhou (average wind speed: 0.82 m s−1.The average mass spectrum of OA showed a medium oxidation degree (average O ∕ C ratio of 0.28, which was lower than that during summer

  7. Material Property Correlations: Comparisons between FRAPCON-3.4, FRAPTRAN 1.4, and MATPRO

    Energy Technology Data Exchange (ETDEWEB)

    Luscher, Walter G.; Geelhood, Kenneth J.

    2010-08-01

    Sections 3 and 4, respectively. In addition to describing the material property correlations used in the subroutines of FRAPCON-3 and FRAPTRAN, this report also provides a variety of comparisons between material property correlations and data. Although they are frequently identical, comparisons are made between the material property correlations used in the FRAPCON-3 and FRAPTRAN codes. Comparisons are also made between the material property correlations used in MATPRO, a compilation of fuel and cladding material property correlations with an extensive history of used with various fuel performance and severe accident codes. For a number of reasons, consistency between the material property correlations in FRAPCON-3, FRAPTRAN, and MATPRO has never been complete. However, the current versions of FRAPCON-3 and FRAPTRAN use a relatively consistent set of correlations for the properties that are used by both codes. The material property correlations in the most recent version of MATPRO are documented in Volume 4 of NUREG/CR-6150. In addition to comparison of the various correlations, correlation-to-data comparisons are also made with FRAPCON-3, FRAPTRAN, and MATPRO. All comparisons made in this report are based on the material property correlations used in the most recent version of the FRAPCON-3 and FRAPTRAN codes, FRAPCON-3.4 and FRAPTRAN 1.4. The source code for each material property correlation discussed will be provided for FRAPCON-3.4 and FRAPTRAN 1.4 (see appendix) as well as a range of applicability and an estimate of uncertainty where possible.

  8. More Realistic Face Model Surface Improves Relevance of Pediatric In-Vitro Aerosol Studies.

    Science.gov (United States)

    Amirav, Israel; Halamish, Asaf; Gorenberg, Miguel; Omar, Hamza; Newhouse, Michael T

    2015-01-01

    Various hard face models are commonly used to evaluate the efficiency of aerosol face masks. Softer more realistic "face" surface materials, like skin, deform upon mask application and should provide more relevant in-vitro tests. Studies that simultaneously take into consideration many of the factors characteristic of the in vivo face are lacking. These include airways, various application forces, comparison of various devices, comparison with a hard-surface model and use of a more representative model face based on large numbers of actual faces. To compare mask to "face" seal and aerosol delivery of two pediatric masks using a soft vs. a hard, appropriately representative, pediatric face model under various applied forces. Two identical face models and upper airways replicas were constructed, the only difference being the suppleness and compressibility of the surface layer of the "face." Integrity of the seal and aerosol delivery of two different masks [AeroChamber (AC) and SootherMask (SM)] were compared using a breath simulator, filter collection and realistic applied forces. The soft "face" significantly increased the delivery efficiency and the sealing characteristics of both masks. Aerosol delivery with the soft "face" was significantly greater for the SM compared to the AC (pmasks was observed with the hard "face." The material and pliability of the model "face" surface has a significant influence on both the seal and delivery efficiency of face masks. This finding should be taken into account during in-vitro aerosol studies.

  9. Behavior of aerosols in a steam-air environment

    International Nuclear Information System (INIS)

    Adams, R.E.; Tobias, M.L.; Longest, A.W.

    1985-01-01

    The behavior of aerosols assumed to be characteristic of those generated during light water reactor (LWR) accident sequences and released into containment is being studied in the Nuclear Safety Pilot Plant (NSPP) which is located at the Oak Ridge National Laboratory (ORNL). The program plan for the NSPP aerosol project provides for the study of the behavior, within containment, of simulated LWR accident aerosols emanating from fuel, reactor core structural materials, and from concrete-molten core materials interactions. The aerodynamic behavior of each of these aerosols was studied individually to establish its characteristics; current experiments involve mixtures of these aerosols to establish their interaction and collective behavior within containment. Tests have been conducted with U 3 O 8 aerosols, Fe 2 O 3 aerosols, and concrete aerosols in an environment of either dry air [relative humidity (RH) less than 20%] or steam-air [relative humidity (RH) approximately 100%] with aerosol mass concentration being the primary experimental variable

  10. Comparison of PM10 concentrations and metal content in three different sites of the Venice Lagoon: an analysis of possible aerosol sources.

    Science.gov (United States)

    Contini, Daniele; Belosi, Franco; Gambaro, Andrea; Cesari, Daniela; Stortini, Angela Maria; Bove, Maria Chiara

    2012-01-01

    The Venice Lagoon is exposed to atmospheric pollutants from industrial activities, thermoelectric power plants, petrochemical plants, incinerator, domestic heating, ship traffic, glass factories and vehicular emissions on the mainland. In 2005, construction began on the mobile dams (MOSE), one dam for each channel connecting the lagoon to the Adriatic Sea as a barrier against high tide. These construction works could represent an additional source of pollutants. PM10 samples were taken on random days between 2007 and 2010 at three different sites: Punta Sabbioni, Chioggia and Malamocco, located near the respective dam construction worksites. Chemical analyses of V, Cr, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl and Pb in PM10 samples were performed by Inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) and results were used to identify the main aerosol sources. The correlation of measured data with meteorology, and source apportionment, failed to highlight a contribution specifically associated to the emissions of the MOSE construction works. The comparison of the measurements at the three sites showed a substantial homogeneity of metal concentrations in the area. Source apportionment with principal component analysis (PCA) and positive matrix factorization (PMF) showed that a four principal factors model could describe the sources of metals in PM10. Three of them were assigned to specific sources in the area and one was characterised as a source of mixed origin (anthropogenic and crustal). A specific anthropogenic source of PM10 rich in Ni and Cr, active at the Chioggia site, was also identified.

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

    Energy Technology Data Exchange (ETDEWEB)

    Svenningsson, B.

    1997-11-01

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

  12. Comparison of Two Xenograft Materials Used in Sinus Lift Procedures: Material Characterization and In Vivo Behavior

    Directory of Open Access Journals (Sweden)

    María Piedad Ramírez Fernández

    2017-06-01

    Full Text Available Detailed information about graft material characteristic is crucial to evaluate their clinical outcomes. The present study evaluates the physico-chemical characteristics of two xenografts manufactured on an industrial scale deproteinized at different temperatures (non-sintered and sintered in accordance with a protocol previously used in sinus lift procedures. It compares how the physico-chemical properties influence the material’s performance in vivo by a histomorphometric study in retrieved bone biopsies following maxillary sinus augmentation in 10 clinical cases. An X-ray diffraction analysis revealed the typical structure of hydroxyapatite (HA for both materials. Both xenografts were porous and exhibited intraparticle pores. Strong differences were observed in terms of porosity, crystallinity, and calcium/phosphate. Histomorphometric measurements on the bone biopsies showed statistically significant differences. The physic-chemical assessment of both xenografts, made in accordance with the protocol developed on an industrial scale, confirmed that these products present excellent biocompatibilitity, with similar characteristics to natural bone. The sintered HA xenografts exhibited greater osteoconductivity, but were not completely resorbable (30.80 ± 0.88% residual material. The non-sintered HA xenografts induced about 25.92 ± 1.61% of new bone and a high level of degradation after six months of implantation. Differences in the physico-chemical characteristics found between the two HA xenografts determined a different behavior for this material.

  13. A seasonal time history of the size resolved composition of fine aerosol in Manchester UK

    Science.gov (United States)

    Choularton, Thomas; Martin, Claire; Allan, James; Coe, Hugh; Bower, Keith; Gallagher, Martin

    2010-05-01

    Numerous studies have been conducted in urban centres now using sophisticated instruments that measure aerosol properties needed to determine their effects on human health, air quality and climate change) showing that a significant fraction of urban aerosols (mainly from automotive sources) are composed of organic compounds with implications for human health. In this project we have produced the first seasonal aerosol composition and emission database for the City of Manchester in the UK Several recent projects have been conducted by SEAES looking at fundamental properties of urban atmospheric aerosol to understand their influence on climate. This work is now expanding through collaboration with the School of Geography & Centre for Occupational & Environmental Health to investigate urban aerosol emission impacts on human health In this paper we present a compendium of data from field campaigns in Manchester city centre over the past decade. The data are from six different campaigns, between 2001 - 2007, each campaign was between 2 weeks and 2 months long predominantly from January and June periods . The data analysis includes air parcel trajectory examination and comparisons with external data, including PM10, CO and NOx data from AURN fixed monitoring sites Six Manchester fine aerosol datasets from the past decade have been quality controlled and analysed regarding averages of the size distributions of Organic, NO3, NH4 and SO4 mass loadings. It was found that: Organic material is the largest single component of the aerosol with primary aliphatic material dominating the smallest sizes, but with oxygenated secondary organic material being important in the accumulation mode. In the accumulation mode the organic material seems to be internally mixed with sulphate and nitrate. The accumulation mode particles were effective as cloud condensation nuclei. Seasonal effects surrounding atmospheric stability and photochemistry were found to play an important role in the

  14. 10 CFR 32.26 - Gas and aerosol detectors containing byproduct material: Requirements for license to manufacture...

    Science.gov (United States)

    2010-01-01

    ...: Requirements for license to manufacture, process, produce, or initially transfer. 32.26 Section 32.26 Energy NUCLEAR REGULATORY COMMISSION SPECIFIC DOMESTIC LICENSES TO MANUFACTURE OR TRANSFER CERTAIN ITEMS... byproduct material: Requirements for license to manufacture, process, produce, or initially transfer. An...

  15. Comparison of swelling for structural materials on neutron and ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Loomis, B.A.

    1986-03-01

    The swelling of V-base alloys, Type 316 stainless steel, Fe-25Ni-15Cr alloys, ferritic steels, Cu, Ni, Nb-1% Zr, and Mo on neutron irradiation is compared with the swelling for these materials on ion irradiation. The results of this comparison show that utilization of the ion-irradiation technique provides for a discriminative assessment of the potential for swelling of candidate materials for fusion reactors.

  16. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use...... of a cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...... a relationship between plunging jet particle ux, oceanic particle ux, and energy dissipation rate in both systems. Previous sea spray aerosol studies dissipate an order of magnitude more energy for the same particle ux production as the open ocean. A scaling factor related to the energy expended in air...

  17. Comparison of computer codes relative to the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

    International Nuclear Information System (INIS)

    Fermandjian, J.; Dunbar, I.; Gauvain, J.; Ricchena, R.

    1986-02-01

    The present study concerns a comparative exercise, performed within the framework of the Commission of the European Communities, of the computer codes (AEROSISM-M, UK; AEROSOLS/BI, France; CORRAL-2, CEC and NAUA Mod5, Germany) used in order to assess the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

  18. Comparison of Select Analytes in Exhaled Aerosol from E-Cigarettes with Exhaled Smoke from a Conventional Cigarette and Exhaled Breaths

    Directory of Open Access Journals (Sweden)

    Gerald A. Long

    2014-10-01

    Full Text Available Exhaled aerosols were collected following the use of two leading U.S. commercial electronic cigarettes (e-cigarettes and a conventional cigarette by human subjects and analyzed for phenolics, carbonyls, water, glycerin and nicotine using a vacuum-assisted filter pad capture system. Exhaled breath blanks were determined for each subject prior to each product use and aerosol collection session. Distribution and mass balance of exhaled e-cigarette aerosol composition was greater than 99.9% water and glycerin, and a small amount (<0.06% of nicotine. Total phenolic content in exhaled e-cigarette aerosol was not distinguishable from exhaled breath blanks, while total phenolics in exhaled cigarette smoke were significantly greater than in exhaled e-cigarette aerosol and exhaled breaths, averaging 66 µg/session (range 36 to 117 µg/session. The total carbonyls in exhaled e-cigarette aerosols were also not distinguishable from exhaled breaths or room air blanks. Total carbonyls in exhaled cigarette smoke was significantly greater than in exhaled e-cigarette aerosols, exhaled breath and room air blanks, averaging 242 µg/session (range 136 to 352 µg/session. These results indicate that exhaled e-cigarette aerosol does not increase bystander exposure for phenolics and carbonyls above the levels observed in exhaled breaths of air.

  19. Chamber for Aerosol Deposition of Bioparticles

    Science.gov (United States)

    Kern, Roger; Kirschner, Larry

    2008-01-01

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

  20. Consideration of turbulent deposition in aerosol behaviour modelling with the CONTAIN code and comparison of the computations to sodium release experiments

    International Nuclear Information System (INIS)

    Jonas, R.

    1988-09-01

    CONTAIN is a computer code to analyze physical, chemical and radiological processes inside the reactor containment in the sequence of severe reactor accident. Modelling of the aerosol behaviour is included. We have improved the code by implementing a subroutine for turbulent deposition of aerosols. In contrast to previous calculations in which this effect was neglected, the computer results are in good agreement with sodium release experiments. If a typical friction velocity of 1 m/s is chosen, the computed aerosol mass median diameters and aerosol mass concentrations agree with the experimental results within a factor of 1.5 or 2, respectively. We have also found a good agreement between the CONTAIN calculations and results from other aerosol codes. (orig.) [de

  1. Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis

    Science.gov (United States)

    Buchard, V.; da Silva, A. M.; Colarco, P. R.; Darmenov, A.; Randles, C. A.; Govindaraju, R.; Torres, O.; Campbell, J.; Spurr, R.

    2015-05-01

    A radiative transfer interface has been developed to simulate the UV aerosol index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and aerosol absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on a version of the GEOS-5 model that is radiatively coupled to the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) aerosol module and includes assimilation of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR), aerosol retrievals from the AErosol RObotic NETwork (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain potential misplacement of plume height by the model. By sampling dust, biomass burning and pollution events in 2007 we have compared model-produced AI and AAOD with the corresponding OMI products, identifying regions where the model representation of absorbing aerosols was deficient. As a result of this study over the Saharan dust region, we have obtained a new set of dust aerosol optical properties that retains consistency with the MODIS AOD data that were assimilated, while resulting in better agreement with aerosol absorption measurements from OMI. The analysis conducted over the southern African and South American biomass burning regions indicates that revising the spectrally dependent aerosol absorption properties in the near-UV region improves the modeled-observed AI comparisons

  2. The European aerosol budget in 2006

    Directory of Open Access Journals (Sweden)

    J. M. J. Aan de Brugh

    2011-02-01

    Full Text Available This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension. We model that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95% and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%. We model transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we underestimate the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match, while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional aerosol budgets, as presented in the current study.

  3. A simple parameterization of aerosol emissions in RAMS

    Science.gov (United States)

    Letcher, Theodore

    Throughout the past decade, a high degree of attention has been focused on determining the microphysical impact of anthropogenically enhanced concentrations of Cloud Condensation Nuclei (CCN) on orographic snowfall in the mountains of the western United States. This area has garnered a lot of attention due to the implications this effect may have on local water resource distribution within the Region. Recent advances in computing power and the development of highly advanced microphysical schemes within numerical models have provided an estimation of the sensitivity that orographic snowfall has to changes in atmospheric CCN concentrations. However, what is still lacking is a coupling between these advanced microphysical schemes and a real-world representation of CCN sources. Previously, an attempt to representation the heterogeneous evolution of aerosol was made by coupling three-dimensional aerosol output from the WRF Chemistry model to the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) (Ward et al. 2011). The biggest problem associated with this scheme was the computational expense. In fact, the computational expense associated with this scheme was so high, that it was prohibitive for simulations with fine enough resolution to accurately represent microphysical processes. To improve upon this method, a new parameterization for aerosol emission was developed in such a way that it was fully contained within RAMS. Several assumptions went into generating a computationally efficient aerosol emissions parameterization in RAMS. The most notable assumption was the decision to neglect the chemical processes in formed in the formation of Secondary Aerosol (SA), and instead treat SA as primary aerosol via short-term WRF-CHEM simulations. While, SA makes up a substantial portion of the total aerosol burden (much of which is made up of organic material), the representation of this process is highly complex and highly expensive within a numerical

  4. Comparison of different PADC materials and etching conditions for fast neutron dosimetry

    International Nuclear Information System (INIS)

    Assenmacher, F.; Boschung, M.; Hohmann, E.; Mayer, S.

    2016-01-01

    Etched-track polyallyl diglycol carbonate (PADC) dosemeters have been in use at the Paul Scherrer Institute since 1998 in neutron dosimetry for individual monitoring. In the last years, the availability of PADC materials from different manufacturers has grown, and different etching conditions were proposed, with the intention to improve the quality and overall performance of PADC in individual neutron monitoring. The goal of the present study was to compare the performance of different PADC materials and to investigate the influence of different etching conditions on sensitivity to fast neutrons and lower detection limit. The comparison covers six different PADC materials and eight different etching conditions. (authors)

  5. Aerosol Climate Time Series Evaluation In ESA Aerosol_cci

    Science.gov (United States)

    Popp, T.; de Leeuw, G.; Pinnock, S.

    2015-12-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of aerosol information from European sensors. By the end of 2015 full mission time series of 2 GCOS-required aerosol parameters are completely validated and released: Aerosol Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing Aerosol Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary aerosol properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer), absorption information and aerosol layer height. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which are also validated. The paper will summarize and discuss the results of major reprocessing and validation conducted in 2015. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension with successor instruments of the Sentinel family will be described and the complementarity of the different satellite aerosol products

  6. Comparison of two different sea-salt aerosol schemes as implemented in air quality models applied to the Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    P. Jiménez-Guerrero

    2011-05-01

    Full Text Available A number of attempts have been made to incorporate sea-salt aerosol (SSA source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution for a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the particle size and the surface wind speed raised to the power 3.41. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around −0.002 and −1.2 μg m−3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA strongly vary across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m−3 and CMAQ in the Gulf of Lion (9 μg m−3. The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes

  7. In-Situ Measurements of Aerosol Optical Properties using New Cavity Ring-Down and Photoacoustics Instruments and Comparison with more Traditional Techniques

    Science.gov (United States)

    Strawa, A. W.; Arnott, P.; Covert, D.; Elleman, R.; Ferrare, R.; Hallar, A. G.; Jonsson, H.; Kirchstetter, T. W.; Luu, A. P.; Ogren, J.

    2004-01-01

    Carbonaceous species (BC and OC) are responsible for most of the absorption associated with aerosol particles. The amount of radiant energy an aerosol absorbs has profound effects on climate and air quality. It is ironic that aerosol absorption coefficient is one of the most difficult aerosol properties to measure. A new cavity ring-down (CRD) instrument, called Cadenza (NASA-ARC), measures the aerosol extinction coefficient for 675 nm and 1550 nm light, and simultaneously measures the scattering coefficient at 675 nm. Absorption coefficient is obtained from the difference of measured extinction and scattering within the instrument. Aerosol absorption coefficient is also measured by a photoacoustic (PA) instrument (DRI) that was operated on an aircraft for the first time during the DOE Aerosol Intensive Operating Period (IOP). This paper will report on measurements made with this new instrument and other in-situ instruments during two field recent field studies. The first field study was an airborne cam;oaign, the DOE Aerosol Intensive Operating Period flown in May, 2003 over northern Oklahoma. One of the main purposes of the IOP was to assess our ability to measure extinction and absorption coefficient in situ. This paper compares measurements of these aerosol optical properties made by the CRD, PA, nephelometer, and Particle Soot Absorption Photometer (PSAP) aboard the CIRPAS Twin-Otter. During the IOP, several significant aerosol layers were sampled aloft. These layers are identified in the remote (AATS-14) as well as in situ measurements. Extinction profiles measured by Cadenza are compared to those derived from the Ames Airborne Tracking Sunphotometer (AATS-14, NASA-ARC). The regional radiative impact of these layers is assessed by using the measured aerosol optical properties in a radiative transfer model. The second study was conducted in the Caldecott Tunnel, a heavily-used tunnel located north of San Francisco, Ca. The aerosol sampled in this study was

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

    International Nuclear Information System (INIS)

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

    1985-09-01

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

  9. Aerosol filtration

    International Nuclear Information System (INIS)

    Klein, M.; Goossens, W.R.A.; De Smet, M.; Trine, J.; Hertschap, M.

    1984-01-01

    This report summarizes the work on the development of fibre metallic prefilters to be placed upstream of HEPA filters for the exhaust gases of nuclear process plants. Investigations at ambient and high temperature were carried out. Measurements of the filtration performance of Bekipor porous webs and sintered mats were performed in the AFLT (aerosol filtration at low temperature) unit with a throughput of 15 m 3 /h. A parametric study on the influence of particle size, fibre diameter, number of layers and superficial velocity led to the optimum choice of the working parameters. Three selected filter types were then tested with polydisperse aerosols using a candle-type filter configuration or a flat-type filter configuration. The small-diameter candle type is not well suited for a spraying nozzles regeneration system so that only the flat-type filter was retained for high-temperature tests. A high-temperature test unit (AFHT) with a throughput of 8 to 10 m 3 /h at 400 0 C was used to test the three filter types with an aerosol generated by high-temperature calcination of a simulated nitric acid waste solution traced with 134 Cs. The regeneration of the filter by spray washing and the effect of the regeneration on the filter performance was studied for the three filter types. The porous mats have a higher dust loading capacity than the sintered web which means that their regeneration frequency can be kept lower

  10. TOMS Absorbing Aerosol Index

    Data.gov (United States)

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  11. Airborne measurement of submicron aerosol number concentration and CCN activity in and around the Korean Peninsula and their comparison to ground measurement in Seoul

    Science.gov (United States)

    Park, M.; Kim, N.; Yum, S. S.

    2016-12-01

    Aerosols exert impact not only on human health and visibility but also on climate change directly by scattering or absorbing solar radiation and indirectly by acting as cloud condensation nuclei (CCN) and thus altering cloud radiative and microphysical properties. Aerosol indirect effects on climate has been known to have large uncertainty because of insufficient measurement data on aerosol and CCN activity distribution. Submicron aerosol number concentration (NCN, TSI CPC) and CCN number concentration (NCCN, DMT CCNC) were measured on board the NASA DC-8 research aircraft and at a ground site at Olympic Park in Seoul from May 2nd to June 10th, 2016. CCNC on the airborne platform was operated with the fixed internal supersaturation of 0.6% and CCNC at the ground site was operated with the five different supersaturations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%). The NASA DC-8 conducted 20 research flights (about 150 hours) in and around the Korean Peninsula and the ground measurement at Olympic Park was continuously made during the measurement period. Both airborne and ground measurements showed spatially and temporally varied aerosol number concentration and CCN activity. Aerosol number concentration in the boundary layer measured on airborne platform was highly affected by pollution sources on the ground. The average diurnal distribution of ground aerosol number concentration showed distinct peaks are located at about 0800, 1500, and 2000. The middle peak indicates that new particle formation events frequently occurred during the measurement period. CCN activation ratio at 0.6% supersaturation (NCCN/NCN) of the airborne measurement ranged from 0.1 to 0.9, indicating that aerosol properties in and around the Korean Peninsula varied so much (e. g. size, hygroscopicity). Comprehensive analysis results will be shown at the conference.

  12. A Comparison of the OSHA Modified NIOSH Physical and Chemical Analytical Method (P and CAM) 304 and the Dust Trak Photometric Aerosol Sampler for 0-Chlorobenzylidine Malonitrile

    Science.gov (United States)

    2013-04-02

    Paper is ripped up and placed inside the coffee can, followed by the opening of CS capsules where granules of the CS are dispersed into the paper... coffee can was placed on top of the hot plate. Paper is ripped up and placed inside the coffee can to assist in the burning of the capsules , capsules ...be re-aerosolized as dried aerosol- particulates. Additionally, the outer casings of the CS capsules and paper were often added to the coffee can to

  13. Estimating marine aerosol particle volume and number from Maritime Aerosol Network data

    Directory of Open Access Journals (Sweden)

    A. M. Sayer

    2012-09-01

    Full Text Available As well as spectral aerosol optical depth (AOD, aerosol composition and concentration (number, volume, or mass are of interest for a variety of applications. However, remote sensing of these quantities is more difficult than for AOD, as it is more sensitive to assumptions relating to aerosol composition. This study uses spectral AOD measured on Maritime Aerosol Network (MAN cruises, with the additional constraint of a microphysical model for unpolluted maritime aerosol based on analysis of Aerosol Robotic Network (AERONET inversions, to estimate these quantities over open ocean. When the MAN data are subset to those likely to be comprised of maritime aerosol, number and volume concentrations obtained are physically reasonable. Attempts to estimate surface concentration from columnar abundance, however, are shown to be limited by uncertainties in vertical distribution. Columnar AOD at 550 nm and aerosol number for unpolluted maritime cases are also compared with Moderate Resolution Imaging Spectroradiometer (MODIS data, for both the present Collection 5.1 and forthcoming Collection 6. MODIS provides a best-fitting retrieval solution, as well as the average for several different solutions, with different aerosol microphysical models. The "average solution" MODIS dataset agrees more closely with MAN than the "best solution" dataset. Terra tends to retrieve lower aerosol number than MAN, and Aqua higher, linked with differences in the aerosol models commonly chosen. Collection 6 AOD is likely to agree more closely with MAN over open ocean than Collection 5.1. In situations where spectral AOD is measured accurately, and aerosol microphysical properties are reasonably well-constrained, estimates of aerosol number and volume using MAN or similar data would provide for a greater variety of potential comparisons with aerosol properties derived from satellite or chemistry transport model data. However, without accurate AOD data and prior knowledge of

  14. Aerosol volatility in a boreal forest environment

    Science.gov (United States)

    Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

    2012-04-01

    Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed

  15. Geometrical optics of dense aerosols: forming dense plasma slabs.

    Science.gov (United States)

    Hay, Michael J; Valeo, Ernest J; Fisch, Nathaniel J

    2013-11-01

    Assembling a freestanding, sharp-edged slab of homogeneous material that is much denser than gas, but much more rarefied than a solid, is an outstanding technological challenge. The solution may lie in focusing a dense aerosol to assume this geometry. However, whereas the geometrical optics of dilute aerosols is a well-developed field, the dense aerosol limit is mostly unexplored. Yet controlling the geometrical optics of dense aerosols is necessary in preparing such a material slab. Focusing dense aerosols is shown here to be possible, but the finite particle density reduces the effective Stokes number of the flow, a critical result for controlled focusing.

  16. The intercomparison of aerosol codes

    International Nuclear Information System (INIS)

    Dunbar, I.H.; Fermandjian, J.; Gauvain, J.

    1988-01-01

    The behavior of aerosols in a reactor containment vessel following a severe accident could be an important determinant of the accident source term to the environment. Various processes result in the deposition of the aerosol onto surfaces within the containment, from where they are much less likely to be released. Some of these processes are very sensitive to particle size, so it is important to model the aerosol growth processes: agglomeration and condensation. A number of computer codes have been written to model growth and deposition processes. They have been tested against each other in a series of code comparison exercises. These exercises have investigated sensitivities to physical and numerical assumptions and have also proved a useful means of quality control for the codes. Various exercises in which code predictions are compared with experimental results are now under way

  17. Aerosol scrubbers

    International Nuclear Information System (INIS)

    Sheely, W.F.

    1986-01-01

    The Submerged Gravel Scrubber is an air cleaning system developed by the Department of Energy's Liquid Metal Reactor Program. The Scrubber System has been patented by the Department of Energy. This technology is being transferred to industry by the DOE. Its basic principles can be adapted for individual applications and the commercialized version can be used to perform a variety of tasks. The gas to be cleaned is percolated through a continuously washed gravel bed. The passage of the gas through the gravel breaks the stream into many small bubbles rising in a turbulent body of water. These conditions allow very highly efficient removal of aerosols from the gas

  18. Calibration of aerosol radiometers. Special aerosol sources

    International Nuclear Information System (INIS)

    Belkina, S.K.; Zalmanzon, Yu.E.; Kuznetsov, Yu.V.; Fertman, D.E.

    1988-01-01

    Problems of calibration of artificial aerosol radiometry and information-measurement systems of radiometer radiation control, in particular, are considered. Special aerosol source is suggested, which permits to perform certification and testing of aerosol channels of the systems in situ without the dismantling

  19. Properties of aerosol particles generated during 213 nm laser ablation: a study of compact and powdered tungsten carbides as materials with a two-component matrix

    International Nuclear Information System (INIS)

    Hola, M.; Konecna, V.; Kanicky, V.; Mikuska, P.; Kaiser, J.; Hanzlikova, R.

    2009-01-01

    Full text: The laser ablation process of tungsten carbide hardmetals was studied using 213 nm Nd:YAG laser. The samples were presented for ablation as sintered compacts or powders pressed into pellets to compare the generation of particles from samples with similar chemical composition but different physical properties. The influence of laser ablation parameters on the aerosol generation was studied using an optical aerosol spectrometer. In the case of powders, the effect of binder amount was investigated. The structure of generated particles and the properties of ablation-craters were additionally studied by SEM. (author)

  20. A Mesoscale Analysis of Column-Integrated Aerosol Properties in Northern India During the TIGERZ 2008 Pre-Monsoon Period and a Comparison to MODIS Retrievals

    Science.gov (United States)

    Giles, D. M.; Holben, B. N.; Tripathi, S. N.; Eck, T. F.; Newcomb, W. W.; Slutsker, I.; Dickerson, R. R.; Thompson, A. M.; Wang, S.-H.; Singh, R. P.; hide

    2010-01-01

    The Indo-Gangetic Plain (IGP) of the northern Indian subcontinent produces anthropogenic pollution from urban, industrial and rural combustion sources nearly continuously and is affected by convection-induced winds driving desert and alluvial dust into the atmosphere during the premonsoon period. Within the IGP, the NASA Aerosol Robotic Network (AERONET) project initiated the TIGERZ measurement campaign in May 2008 with an intensive operational period from May 1 to June 23, 2008. Mesoscale spatial variability of aerosol optical depth (AOD, tau) measurements at 500mn was assessed at sites around Kanpur, India, with averages ranging from 0.31 to 0.89 for spatial variability study (SVS) deployments. Sites located downwind from the city of Kanpur indicated slightly higher average aerosol optical depth (delta Tau(sub 500)=0.03-0.09). In addition, SVS AOD area-averages were compared to the long-tenn Kanpur AERONET site data: Four SVS area-averages were within +/- 1 cr of the climatological mean of the Kanpur site, while one SVS was within 2sigma below climatology. For a SVS case using AERONET inversions, the 440-870mn Angstrom exponent of approximately 0.38, the 440-870mn absorption Angstrom exponent (AAE) of 1.15-1.53, and the sphericity parameter near zero suggested the occurrence of large, strongly absorbing, non-spherical aerosols over Kanpur (e.g., mixed black carbon and dust) as well as stronger absorption downwind of Kanpur. Furthermore, the 3km and lOkm Terra and Aqua MODIS C005 aerosol retrieval algorithms at tau(sub 550) were compared to the TIGERZ data set. Although MODIS retrievals at higher quality levels were comparable to the MODIS retrieval uncertainty, the total number of MODIS matchups (N) were reduced with subsequent quality levels (N=25, QA>=0; N=9,QA>=l; N=6, QA>=2; N=1, QA=3) over Kanpur during the premonsoon primarily due to the semi-bright surface, complex aerosol mixture and cloud-contaminated pixels. The TIGERZ 2008 data set provided a unique

  1. Theophylline Cocrystals Prepared by Spray Drying: Physicochemical Properties and Aerosolization Performance

    OpenAIRE

    Alhalaweh, Amjad; Kaialy, Waseem; Buckton, Graham; Gill, Hardyal; Nokhodchi, Ali; Velaga, Sitaram P.

    2013-01-01

    The purpose of this work was to characterize theophylline (THF) cocrystals prepared by spray drying in terms of the physicochemical properties and inhalation performance when aerosolized from a dry powder inhaler. Cocrystals of theophylline with urea (THF-URE), saccharin (THF-SAC) and nicotinamide (THF-NIC) were prepared by spray drying. Milled THF and THF-SAC cocrystals were also used for comparison. The physical purity, particle size, particle morphology and surface energy of the materials ...

  2. Study of filterable materials and protection instruments by the use of radioactive aerosols; Etude de materiaux filtrants et d'appareils de protection a l'aide des aerosols radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Billard,; Chevalier,; Pradel, [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Many filtration problems can be studied by means of radioactive aerosols. For the investigations described in this paper we have chosen the solid disintegration products of radon, the radioactive gas formed from radium, because of the facilities of generation and measurement it offers. Radon and its daughters are in fact always present in the atmosphere in sufficient concentration for certain tests. In order to improve the sensitivity of the measurements, radon from uranium ore can be used. The technique of measuring by counting {alpha} particles is rapid and easy to employ. We have thus been able to define a test for filterable substances, and to check filtering installation and individual protection instruments. (author) [French] Les aerosols radioactifs permettent d'etudier de nombreux problemes de filtration. Pour les etudes decrites dans ce document, nous avons choisi les produits solides de desintegration du radon, gaz radioactif forme a partir du radium en raison des facilites de generation et de mesure. Le radon et ses descendants sont, en effet, toujours presents dans l'atmosphere en concentration suffisante pour certains essais. Pour ameliorer la sensibilite des mesures, il suffit d'utiliser le radon provenant de minerai d'uranium. La technique de mesure par comptage des particules {alpha} est rapide et facile a mettre en oeuvre. Nous avons pu ainsi definir un test pour les substances filtrantes et controler les installations de filtration et des appareils de protection individuelle. (auteur)

  3. Aerosols and the lungs

    International Nuclear Information System (INIS)

    1987-01-01

    The lectures of the colloquium are discussed in summary form. There were 5 lectures on aerosol deposition, 5 on aerosol elimination, 7 on toxicology, and 7 on the uses of aerosols in medical therapy. In some cases aerosols with radioactive labels were used. Several lectures reviewed the kinetics and toxicology of airborne environmental pollutants. (MG) [de

  4. Final Report: Part 1. In-Place Filter Testing Instrument for Nuclear Material Containers. Part 2. Canister Filter Test Standards for Aerosol Capture Rates.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Austin Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Runnels, Joel T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reeves, Kirk Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-02

    A portable instrument has been developed to assess the functionality of filter sand o-rings on nuclear material storage canisters, without requiring removal of the canister lid. Additionally, a set of fifteen filter standards were procured for verifying aerosol leakage and pressure drop measurements in the Los Alamos Filter Test System. The US Department of Energy uses several thousand canisters for storing nuclear material in different chemical and physical forms. Specialized filters are installed into canister lids to allow gases to escape, and to maintain an internal ambient pressure while containing radioactive contaminants. Diagnosing the condition of container filters and canister integrity is important to ensure worker and public safety and for determining the handling requirements of legacy apparatus. This report describes the In-Place-Filter-Tester, the Instrument Development Plan and the Instrument Operating Method that were developed at the Los Alamos National Laboratory to determine the “as found” condition of unopened storage canisters. The Instrument Operating Method provides instructions for future evaluations of as-found canisters packaged with nuclear material. Customized stainless steel canister interfaces were developed for pressure-port access and to apply a suction clamping force for the interface. These are compatible with selected Hagan-style and SAVY-4000 storage canisters that were purchased from NFT (Nuclear Filter Technology, Golden, CO). Two instruments were developed for this effort: an initial Los Alamos POC (Proof-of-Concept) unit and the final Los Alamos IPFT system. The Los Alamos POC was used to create the Instrument Development Plan: (1) to determine the air flow and pressure characteristics associated with canister filter clogging, and (2) to test simulated configurations that mimicked canister leakage paths. The canister leakage scenarios included quantifying: (A) air leakage due to foreign material (i.e. dust and hair

  5. Characterization of aerosols produced by surgical procedures

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States); Turner, R.S. [Lovelace Health Systems, Albuquerque, NM (United States)

    1994-07-01

    In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

  6. Comparison of polymer-based temporary crown and fixed partial denture materials by diametral tensile strength.

    Science.gov (United States)

    Ha, Seung-Ryong; Yang, Jae-Ho; Lee, Jai-Bong; Han, Jung-Suk; Kim, Sung-Hun

    2010-03-01

    The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (ø 4 mm × 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (α = 0.05). Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.

  7. Multielement comparison of instrumental neutron activation analysis techniques using reference materials

    International Nuclear Information System (INIS)

    Ratner, R.T.; Vernetson, W.G.

    1995-01-01

    Several instrumental neutron activation analysis techniques (parametric, comparative, and k o -standardization) are evaluated using three reference materials. Each technique is applied to National Institute of Standards and Technology standard reference materials, SRM 1577a (Bovine Liver) and SRM 2704 (Buffalo River Sediment), and the United States Geological Survey standard BHVO-1 (Hawaiian Basalt Rock). Identical (but not optimum) irradiation, decay, and counting schemes are employed with each technique to provide a basis for comparison and to determine sensitivities in a routine irradiation scheme. Fifty-one elements are used in this comparison; however, several elements are not detected in the reference materials due to rigid analytical conditions (e.g. insufficient length of irradiation or activity for radioisotope of interest decaying below the lower limit of detection before counting interval). Most elements are normally distributed around certified or consensus values with a standard deviation of 10%. For some elements, discrepancies are observed and discussed. The accuracy, precision, and sensitivity of each technique are discussed by comparing the analytical results to consensus values for the Hawaiian Basalt Rock to demonstrate the diversity of multielement applications. (author) 4 refs.; 2 tabs

  8. Materials used for indirect pulp treatment in primary teeth: a mixed treatment comparisons meta-analysis

    Directory of Open Access Journals (Sweden)

    Pablo Silveira dos Santos

    2017-12-01

    Full Text Available Abstract: This study aimed to systematically review the literature to address the question regarding the influence of different materials in the clinical and radiographic success of indirect pulp treatment in primary teeth. A literature search was carried out for articles published prior to January 2017 in PubMed/MEDLINE, CENTRAL, Scopus, TRIP and ClinicalTrials databases; relevant articles included randomized clinical trials that compared materials used for indirect pulp treatment in primary teeth. Two reviewers independently selected the studies and extracted the data. The effects of each material on the outcome (clinical and radiographic failures were analyzed using a mixed treatment comparisons meta-analysis. The ranking of treatments according to their probability of being the best choice was also calculated. From 1,088 potentially eligible studies, 11 were selected for full-text analysis, and 4 were included in the meta-analysis. In all papers, calcium hydroxide liner was used as the control group versus an adhesive system, resin-modified glass ionomer cement or placebo. The follow-up period ranged from 24 to 48 months, with dropout rates of 0-25.7%. The material type did not significantly affect the risk of failure of the indirect pulp treatment. However, calcium hydroxide presented a higher probability of failure. In conclusion, there is no scientific evidence showing the superiority of any material used for indirect pulp treatment in primary teeth.

  9. A novel hybrid tobacco product that delivers a tobacco flavour note with vapour aerosol (Part 2): In vitro biological assessment and comparison with different tobacco-heating products.

    Science.gov (United States)

    Breheny, Damien; Adamson, Jason; Azzopardi, David; Baxter, Andrew; Bishop, Emma; Carr, Tony; Crooks, Ian; Hewitt, Katherine; Jaunky, Tomasz; Larard, Sophie; Lowe, Frazer; Oke, Oluwatobiloba; Taylor, Mark; Santopietro, Simone; Thorne, David; Zainuddin, Benjamin; Gaça, Marianna; Liu, Chuan; Murphy, James; Proctor, Christopher

    2017-08-01

    This study assessed the toxicological and biological responses of aerosols from a novel hybrid tobacco product. Toxicological responses from the hybrid tobacco product were compared to those from a commercially available Tobacco Heating Product (c-THP), a prototype THP (p-THP) and a 3R4F reference cigarette, using in vitro test methods which were outlined as part of a framework to substantiate the risk reduction potential of novel tobacco and nicotine products. Exposure matrices used included total particulate matter (TPM), whole aerosol (WA), and aqueous aerosol extracts (AqE) obtained after machine-puffing the test products under the Health Canada Intense smoking regime. Levels of carbonyls and nicotine in these matrices were measured to understand the aerosol dosimetry of the products. The hybrid tobacco product tested negative across the in vitro assays including mutagenicity, genotoxicity, cytotoxicity, tumour promotion, oxidative stress and endothelial dysfunction. All the THPs tested demonstrated significantly reduced responses in these in vitro assays when compared to 3R4F. The findings suggest these products have the potential for reduced health risks. Further pre-clinical and clinical assessments are required to substantiate the risk reduction of these novel products at individual and population levels. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. PIXE analysis of atmospheric aerosol and hydrometeor particles

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  11. On the radiative impact of aerosols on photolysis rates: comparison of simulations and observations in the Lampedusa island during the ChArMEx/ADRIMED campaign

    Directory of Open Access Journals (Sweden)

    S. Mailler

    2016-02-01

    Full Text Available The Mediterranean basin is characterized by large concentrations of aerosols from both natural and anthropogenic sources. These aerosols affect tropospheric photochemistry by modulating the photolytic rates. Three simulations of the atmospheric composition at basin scale have been performed with the CHIMERE chemistry-transport model for the period from 6 June to 15 July 2013 covered by the ADRIMED campaign, a campaign of intense measurements in the western Mediterranean basin. One simulation takes into account the radiative effect of the aerosols on photochemistry, the second one does not, and the third one is designed to quantify the model sensitivity to a bias in the ozone column. These simulations are compared to satellite and ground-based measurements, with a particular focus on the area of Lampedusa. Values of the aerosol optical depth (AOD are obtained from the MODIS instrument on the AQUA and TERRA satellites as well as from stations in the AERONET network and from the MFRSR sun photometer deployed at Lampedusa. Additional measurements from instruments deployed at Lampedusa either permanently or exceptionally are used for other variables: MFRSR sun photometer for AOD, diode array spectrometer for actinic fluxes, LIDAR for the aerosol backscatter, sequential sampler for speciation of aerosol and Brewer spectrophotometer for the total ozone column. It is shown that CHIMERE has a significant ability to reproduce observed peaks in the AOD, which in Lampedusa are mainly due to dust outbreaks during the ADRIMED period, and that taking into account the radiative effect of the aerosols in CHIMERE considerably improves the ability of the model to reproduce the observed day-to-day variations of the photolysis rate of ozone to O2 and O(1D, J(O1D, and that of NO2 to NO and O(3P, J(NO2. While in the case of J(O1D other variation factors such as the stratospheric ozone column are very important in representing correctly the day-to-day variations

  12. Aerosol Transport Over Equatorial Africa

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H. J.; Kinyua, A. M.; Piketh, S.; King, M.; Helas, G.

    1999-01-01

    Long-range and inter-hemispheric transport of atmospheric aerosols over equatorial Africa has received little attention so far. Most aerosol studies in the region have focussed on emissions from rain forest and savanna (both natural and biomass burning) and were carried out in the framework of programs such as DECAFE (Dynamique et Chimie Atmospherique en Foret Equatoriale) and FOS (Fires of Savanna). Considering the importance of this topic, aerosols samples were measured in different seasons at 4420 meters on Mt Kenya and on the equator. The study is based on continuous aerosol sampling on a two stage (fine and coarse) streaker sampler and elemental analysis by Particle Induced X-ray Emission. Continuous samples were collected for two seasons coinciding with late austral winter and early austral spring of 1997 and austral summer of 1998. Source area identification is by trajectory analysis and sources types by statistical techniques. Major meridional transports of material are observed with fine-fraction silicon (31 to 68 %) in aeolian dust and anthropogenic sulfur (9 to 18 %) being the major constituents of the total aerosol loading for the two seasons. Marine aerosol chlorine (4 to 6 %), potassium (3 to 5 %) and iron (1 to 2 %) make up the important components of the total material transport over Kenya. Minimum sulfur fluxes are associated with recirculation of sulfur-free air over equatorial Africa, while maximum sulfur concentrations are observed following passage over the industrial heartland of South Africa or transport over the Zambian/Congo Copperbelt. Chlorine is advected from the ocean and is accompanied by aeolian dust recirculating back to land from mid-oceanic regions. Biomass burning products are transported from the horn of Africa. Mineral dust from the Sahara is transported towards the Far East and then transported back within equatorial easterlies to Mt Kenya. This was observed during austral summer and coincided with the dying phase of 1997/98 El

  13. Comparison of intrapulmonary and systemic pharmacokinetics of colistin methanesulfonate (CMS) and colistin after aerosol delivery and intravenous administration of CMS in critically ill patients.

    Science.gov (United States)

    Boisson, Matthieu; Jacobs, Matthieu; Grégoire, Nicolas; Gobin, Patrice; Marchand, Sandrine; Couet, William; Mimoz, Olivier

    2014-12-01

    Colistin is an old antibiotic that has recently gained a considerable renewal of interest for the treatment of pulmonary infections due to multidrug-resistant Gram-negative bacteria. Nebulization seems to be a promising form of administration, but colistin is administered as an inactive prodrug, colistin methanesulfonate (CMS); however, differences between the intrapulmonary concentrations of the active moiety as a function of the route of administration in critically ill patients have not been precisely documented. In this study, CMS and colistin concentrations were measured on two separate occasions within the plasma and epithelial lining fluid (ELF) of critically ill patients (n = 12) who had received 2 million international units (MIU) of CMS by aerosol delivery and then intravenous administration. The pharmacokinetic analysis was conducted using a population approach and completed by pharmacokinetic-pharmacodynamic (PK-PD) modeling and simulations. The ELF colistin concentrations varied considerably (9.53 to 1,137 mg/liter), but they were much higher than those in plasma (0.15 to 0.73 mg/liter) after aerosol delivery but not after intravenous administration of CMS. Following CMS aerosol delivery, typically, 9% of the CMS dose reached the ELF, and only 1.4% was presystemically converted into colistin. PK-PD analysis concluded that there was much higher antimicrobial efficacy after CMS aerosol delivery than after intravenous administration. These new data seem to support the use of aerosol delivery of CMS for the treatment of pulmonary infections in critical care patients. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  14. Comparison of materials resistance to rupture for low-cycle fatigue under isothermal and nonisothermal conditions

    International Nuclear Information System (INIS)

    Sobolev, N.D.; Egorov, V.I.

    1979-01-01

    Proposed is the following conception of damage at cyclic change of deformation and temperature allowing for two effects: 1) material damage occurs mainly in the stretching semicycle and the higher the temperature and the greater the ageing time, the greater the material damage; 2) the healing effect may take place in the compression semicycle and the higher the temperature and the greater the ageing time, the greater the effect. Comparison in durability of some loading conditions is carried out for the 304 stainless steel to confirm the above conception. It is shown that it is necessary to take into account separately damages is stretching and compression semicycles with allowance for temperature and durability of active loading and holdings

  15. Comparison of relative INAA and k0-INAA using soil and sediment reference materials

    International Nuclear Information System (INIS)

    Jacimovic, R.

    2014-01-01

    The objective of this work was to compare the results obtained by the relative INAA and k 0 -INAA methods for the same input parameters (sample mass, nuclear data, net peak area for the same gamma line and the same measurement and same cooling and measurement times). In total eight environmental soil and sediment reference materials (RM) or certified reference materials (CRM) from different producers were analysed. In this work only the recommended or certified values were considered, allowing comparison of the two methods for 30 elements. The results point out that k 0 -INAA possesses superior qualities compared to relative INAA, being insensitive to flux gradients, and independent of recommended/certified values in RMs/CRMs, often used as standards in relative INAA. (author)

  16. Theophylline cocrystals prepared by spray drying: physicochemical properties and aerosolization performance.

    Science.gov (United States)

    Alhalaweh, Amjad; Kaialy, Waseem; Buckton, Graham; Gill, Hardyal; Nokhodchi, Ali; Velaga, Sitaram P

    2013-03-01

    The purpose of this work was to characterize theophylline (THF) cocrystals prepared by spray drying in terms of the physicochemical properties and inhalation performance when aerosolized from a dry powder inhaler. Cocrystals of theophylline with urea (THF-URE), saccharin (THF-SAC) and nicotinamide (THF-NIC) were prepared by spray drying. Milled THF and THF-SAC cocrystals were also used for comparison. The physical purity, particle size, particle morphology and surface energy of the materials were determined. The in vitro aerosol performance of the spray-dried cocrystals, drug-alone and a drug-carrier aerosol, was assessed. The spray-dried particles had different size distributions, morphologies and surface energies. The milled samples had higher surface energy than those prepared by spray drying. Good agreement was observed between multi-stage liquid impinger and next-generation impactor in terms of assessing spray-dried THF particles. The fine particle fractions of both formulations were similar for THF, but drug-alone formulations outperformed drug-carrier formulations for the THF cocrystals. The aerosolization performance of different THF cocrystals was within the following rank order as obtained from both drug-alone and drug-carrier formulations: THF-NIC>THF-URE>THF-SAC. It was proposed that micromeritic properties dominate over particle surface energy in terms of determining the aerosol performance of THF cocrystals. Spray drying could be a potential technique for preparing cocrystals with modified physical properties.

  17. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

    International Nuclear Information System (INIS)

    Mazurek, M.A.; Cofer, W.R. III; Levine, J.S.

    1991-01-01

    Smoke aerosol and background aerosol particles were collected from the controlled burning of boreal forest where vegetation species and relative mass distributions are known. Chemical mass balances were constructed for the total mass of carbonaceous aerosol particles emitted during the prescribed burn. In addition, a carbonaceous species inventory was developed for aerosol particles presnt under background, smoldering, and full-fire conditions; the production of organic carbon and elemental carbon particles is noted for these two fire regimes. Distributions of the solvent-soluble organic components of the sampled aerosols were generated to identify molecular properties that can be traced to unburned and pyrolyzed materials present in the boreal forest fuels

  18. Aerosol Climate Time Series in ESA Aerosol_cci

    Science.gov (United States)

    Popp, Thomas; de Leeuw, Gerrit; Pinnock, Simon

    2016-04-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of aerosol information from European sensors. Meanwhile, full mission time series of 2 GCOS-required aerosol parameters are completely validated and released: Aerosol Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing Aerosol Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary aerosol properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer, but also from ATSR instruments and the POLDER sensor), absorption information and aerosol layer height. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which were also validated and improved in the reprocessing. For the three ATSR algorithms the use of an ensemble method was tested. The paper will summarize and discuss the status of dataset reprocessing and validation. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension

  19. Intercomparison test of various aerosol measurement techniques

    International Nuclear Information System (INIS)

    Cherdron, W.; Hassa, C.; Jordan, S.

    1984-01-01

    At the suggestion of the CONT group (Containment Loading and Response), which is a subgroup of the Safety Working Group of the Fast Reactor Coordinating Committee, a group of experts undertook a comparison of the techniques of sodium aerosol measurement used in various laboratories in the EC. The following laboratories took part in the exercise: CEN-Mol (Belgium), CEA-Cadarache (France), CEA-Fontenay-aux-Roses (France), KfK-Karlsruhe (Federal Republic of Germany), ENEA-Bologna (Italy), and UKAEA-Winfrith (United Kingdom). The objective of the aerosol measurement workshop was to assess the applicability and reliability of specific aerosol measuring instruments. Measurements performed with equipment from the participating laboratories were evaluated using a standard procedure. This enabled an estimate of the accuracy of the experimental data to be provided for the verification of aerosol codes. Thus these results can be used as input for the physical modelling of aerosol behaviour, and the work reported here is a contribution to the definition of the radioactive source term for severe accidents in LMFBRs. The aerosol experts participating in the exercise agreed to concentrate on the techniques of measuring aerosol particle size distributions. The tests were performed at the FAUNA test facility using the aerosol loop. A sodium spray fire, which provides a continuous aerosol source of variable concentration, was produced under open-loop conditions in this facility. Although the primary objective of the workshop was to determine the particle size distributions of the aerosols, measurements of the sodium mass concentration were also made

  20. Aerosol modelling and validation during ESCOMPTE 2001

    Science.gov (United States)

    Cousin, F.; Liousse, C.; Cachier, H.; Bessagnet, B.; Guillaume, B.; Rosset, R.

    The ESCOMPTE 2001 programme (Atmospheric Research. 69(3-4) (2004) 241) has resulted in an exhaustive set of dynamical, radiative, gas and aerosol observations (surface and aircraft measurements). A previous paper (Atmospheric Research. (2004) in press) has dealt with dynamics and gas-phase chemistry. The present paper is an extension to aerosol formation, transport and evolution. To account for important loadings of primary and secondary aerosols and their transformation processes in the ESCOMPTE domain, the ORISAM aerosol module (Atmospheric Environment. 35 (2001) 4751) was implemented on-line in the air-quality Meso-NH-C model. Additional developments have been introduced in ORganic and Inorganic Spectral Aerosol Module (ORISAM) to improve the comparison between simulations and experimental surface and aircraft field data. This paper discusses this comparison for a simulation performed during one selected day, 24 June 2001, during the Intensive Observation Period IOP2b. Our work relies on BC and OCp emission inventories specifically developed for ESCOMPTE. This study confirms the need for a fine resolution aerosol inventory with spectral chemical speciation. BC levels are satisfactorily reproduced, thus validating our emission inventory and its processing through Meso-NH-C. However, comparisons for reactive species generally denote an underestimation of concentrations. Organic aerosol levels are rather well simulated though with a trend to underestimation in the afternoon. Inorganic aerosol species are underestimated for several reasons, some of them have been identified. For sulphates, primary emissions were introduced. Improvement was obtained too for modelled nitrate and ammonium levels after introducing heterogeneous chemistry. However, no modelling of terrigeneous particles is probably a major cause for nitrates and ammonium underestimations. Particle numbers and size distributions are well reproduced, but only in the submicrometer range. Our work points out

  1. Comparison of the color stability of provisional restorative materials after storing in different drinks

    Directory of Open Access Journals (Sweden)

    Merve Bankoğlu Güngör

    2016-05-01

    Full Text Available OBJECTIVE: The objective of the present study was to compare the color stability of provisional restorative materials after stroring in different drinks. MATERIALS AND METHOD: Thirty specimens (10 mm in diameter and 2 mm in thickness were prepared from three different materials (Temdent, TRIAD ve TelioCAD. Specimens were divided into six groups according to drinks (distilled water, coffee, tea, cola, red wine and fruit juice; n=5. Specimens were stored in these drinks at 37 °C for 48 hours. The L*, a*, b* values of the specimens were measured with a spectrophometer and recorded before and after storing in drinks. Then ΔE* values were calculated. The data were statistically analyzed using two-way analysis of variance (ANOVA and Tukey’s HSD post hoc tests (α=0.05. RESULTS: Difference between the ΔE* values of specimens stored in different drinks was statistically significant (p<0.05. Color change of TelioCAD specimens was smallest in cola drink and greatest in red wine. Color change of Temdent specimens was smallest in fruit juice and greatest in coffee. For TRIAD specimens, greater color change was observed in coffee, red wine, and tea, in descending order. When the results of storing in the same drink were compared, TRIAD showed the greatest values of color change in coffee and red wine in comparison to the other provisional materials (p<0.05. CONCLUSION: Color stability changed according to the type of the provisional material and the drink. When the drinks were evaluated, greater color changes were observed in coffee, and when the materials were evaluated greater color changes were observed in TRIAD.

  2. Dust in the Sky: Atmospheric Composition. Modeling of Aerosol Optical Thickness

    Science.gov (United States)

    Chin, Mian; Ginoux, Paul; Kinne, Stefan; Torres, Omar; Holben, Brent; Duncan, Bryan; Martin, Randall; Logan, Jennifer; Higurashi, Akiko; Nakajima, Teruyuki

    2000-01-01

    Aerosol is any small particle of matter that rests suspended in the atmosphere. Natural sources, such as deserts, create some aerosols; consumption of fossil fuels and industrial activity create other aerosols. All the microscopic aerosol particles add up to a large amount of material floating in the atmosphere. You can see the particles in the haze that floats over polluted cities. Beyond this visible effect, aerosols can actually lower temperatures. They do this by blocking, or scattering, a portion of the sun's energy from reaching the surface. Because of this influence, scientists study the physical properties of atmospheric aerosols. Reliable numerical models for atmospheric aerosols play an important role in research.

  3. Comparison of Aerosol Optical and Microphysical Retrievals from HSRL-2 and in-Situ Measurements During DISCOVER-AQ 2013 (California and Texas

    Directory of Open Access Journals (Sweden)

    Sawamura Patricia

    2016-01-01

    Full Text Available The combination of backscatter coefficients measured at 355, 532 and 1064 nm and extinction coefficients at 355 and 532 nm (i.e. 3β+2α can be used to retrieve profiles of optical and microphysical properties of aerosols, such as effective radius, total volume concentration and total number concentration. NASA LaRC HSRL-2 is an airborne multi-wavelength high spectral resolution lidar in operation that provides the full 3β+2α dataset. HSRL-2 was deployed during DISCOVER-AQ along with other airborne and ground-based instruments that also measured many aerosol parameters in close proximity to the HSRL-2 system, allowing us to evaluate the performance of an automated and unsupervised retrieval algorithm that has been recently developed. We present the results from California (Jan/Feb 2013 and Texas (Sep 2013 DISCOVER-AQ.

  4. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques

    Directory of Open Access Journals (Sweden)

    O. Schmid

    2006-01-01

    Full Text Available Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP, have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ Aethalometer became commercially available, which covers the visible (VIS to near-infrared (NIR spectral range (λ=450–950 nm, and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999. On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering, which is significantly larger than the factors previously reported (~2 for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external as a likely cause. For

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

    Science.gov (United States)

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

    2015-06-24

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

  6. Development of an aerosol decontamination factor evaluation method using an aerosol spectrometer

    International Nuclear Information System (INIS)

    Kanai, Taizo; Furuya, Masahiro; Arai, Takahiro; Nishi, Yoshihisa

    2016-01-01

    Highlights: • Aerosol DF of each diameter is evaluable by using optical scattering method. • Outlet aerosol concentration shows exponential decay by the submergence. • This decay constant depends on the aerosol diameter. • Aerosol DF at water scrubber is described by simple equation. - Abstract: During a severe nuclear power plant accident, the release of fission products into containment and an increase in containment pressure are assumed to be possible. When the containment is damaged by excess pressure or temperature, radioactive materials are released. Pressure suppression pools, containment spray systems and a filtered containment venting system (FCVS) reduce containment pressure and reduce the radioactive release into the environment. These devices remove radioactive materials via various mechanisms. Pressure suppression pools remove radioactive materials by pool scrubbing. Spray systems remove radioactive materials by droplet−aerosol interaction. FCVS, which is installed in the exhaust system, comprises multi-scrubbers (venturi-scrubber, pool scrubbing, static mixer, metal−fiber filter and molecular sieve). For the particulate radioactive materials, its size affects the removal performance and a number of studies have been performed on the removal effect of radioactive materials. This study has developed a new means of evaluating aerosol removal efficiency. The aerosol number density of each effective diameter (light scattering equivalent diameter) is measured using an optical method, while the decontamination factor (DF) of each effective diameter is evaluated by the inlet outlet number density ratio. While the applicable scope is limited to several conditions (geometry of test section: inner diameter 500 mm × height 8.0 m, nozzle shape and air-water ambient pressure conditions), this study has developed a numerical model which defines aerosol DF as a function of aerosol diameter (d) and submergences (x).

  7. Development of an aerosol decontamination factor evaluation method using an aerosol spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kanai, Taizo, E-mail: t-kanai@criepi.denken.or.jp; Furuya, Masahiro, E-mail: furuya@criepi.denken.or.jp; Arai, Takahiro, E-mail: t-arai@criepi.denken.or.jp; Nishi, Yoshihisa, E-mail: y-nishi@criepi.denken.or.jp

    2016-07-15

    Highlights: • Aerosol DF of each diameter is evaluable by using optical scattering method. • Outlet aerosol concentration shows exponential decay by the submergence. • This decay constant depends on the aerosol diameter. • Aerosol DF at water scrubber is described by simple equation. - Abstract: During a severe nuclear power plant accident, the release of fission products into containment and an increase in containment pressure are assumed to be possible. When the containment is damaged by excess pressure or temperature, radioactive materials are released. Pressure suppression pools, containment spray systems and a filtered containment venting system (FCVS) reduce containment pressure and reduce the radioactive release into the environment. These devices remove radioactive materials via various mechanisms. Pressure suppression pools remove radioactive materials by pool scrubbing. Spray systems remove radioactive materials by droplet−aerosol interaction. FCVS, which is installed in the exhaust system, comprises multi-scrubbers (venturi-scrubber, pool scrubbing, static mixer, metal−fiber filter and molecular sieve). For the particulate radioactive materials, its size affects the removal performance and a number of studies have been performed on the removal effect of radioactive materials. This study has developed a new means of evaluating aerosol removal efficiency. The aerosol number density of each effective diameter (light scattering equivalent diameter) is measured using an optical method, while the decontamination factor (DF) of each effective diameter is evaluated by the inlet outlet number density ratio. While the applicable scope is limited to several conditions (geometry of test section: inner diameter 500 mm × height 8.0 m, nozzle shape and air-water ambient pressure conditions), this study has developed a numerical model which defines aerosol DF as a function of aerosol diameter (d) and submergences (x).

  8. A Comparison of the Pharmacokinetics and Pulmonary Lymphatic Exposure of a Generation 4 PEGylated Dendrimer Following Intravenous and Aerosol Administration to Rats and Sheep.

    Science.gov (United States)

    Ryan, Gemma M; Bischof, Robert J; Enkhbaatar, Perenlei; McLeod, Victoria M; Chan, Linda J; Jones, Seth A; Owen, David J; Porter, Christopher J H; Kaminskas, Lisa M

    2016-02-01

    Cancer metastasis to pulmonary lymph nodes dictates the need to deliver chemotherapeutic and diagnostic agents to the lung and associated lymph nodes. Drug conjugation to dendrimer-based delivery systems has the potential to reduce toxicity, enhance lung retention and promote lymphatic distribution in rats. The current study therefore evaluated the pharmacokinetics and lung lymphatic exposure of a PEGylated dendrimer following inhaled administration. Plasma pharmacokinetics and disposition of a 22 kDa PEGylated dendrimer were compared after aerosol administration to rats and sheep. Lung-derived lymph could not be sampled in rats and so lymphatic transport of the dendrimer from the lung was assessed in sheep. Higher plasma concentrations were achieved when dendrimer was administered to the lungs of rats as a liquid instillation when compared to an aerosol. Plasma pharmacokinetics were similar between sheep and rats, although some differences in disposition patterns were evident. Unexpectedly, less than 0.5% of the aerosol dose was recovered in pulmonary lymph. The data suggest that rats provide a relevant model for assessing the pharmacokinetics of inhaled macromolecules prior to evaluation in larger animals, but that the pulmonary lymphatics are unlikely to play a major role in the absorption of nanocarriers from the lungs.

  9. 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

  10. AEROSOL AND GAS MEASUREMENT

    Science.gov (United States)

    Measurements provide fundamental information for evaluating and managing the impact of aerosols on air quality. Specific measurements of aerosol concentration and their physical and chemical properties are required by different users to meet different user-community needs. Befo...

  11. Neutron activation analysis of Standard Materials of Comparison IAEA- the corn and soya flour

    International Nuclear Information System (INIS)

    Dadakhanov, J.A.; Sadykov, I.I.; Salimov, M.I.

    2005-01-01

    It is known that maintenance of quality of results of neutron activation analysis (NAA), no less than in other analytical methods, is one of key problems. Thus first of all it is necessary to provide correctness of results. The most correct way of revealing and elimination of regular errors is carrying out of analyses of Standard Samples of Comparison (SSC) by the developed techniques and comparison of the received results with the certificated results. Therefore, the analysis and certification of various SSC is one of the most actual tasks of modern analytical chemistry. One of few organizations engaged in manufacture SSC for NAA, is IAEA which has organized the Project on certification of samples of comparison - a corn and soya flour. Among many laboratories worldwide, in this Project the Laboratory of the Activation Analysis of Pure Materials of Institute of Nuclear Physics Academy of Sciences Republic of Uzbekistan also participated. We carry out series of analyses of samples of corn and soya flour, candidates for standard samples of comparison, by the method of instrumental NAA. The preparing of samples was carried out by the technique described in the technical project applied to these materials. Samples before the analysis dried up at temperature 80 degree C during 24 h. Cooled, weighed and irradiated in the vertical channel of a nuclear reactor of VVR-SM of Institute of Nuclear Physics Academy of Sciences Republic of Uzbekistan during 0,5-1 h (depending on determined elements) with density of a stream of neutrons 1 x 10 14 neutrons/cm 2 sec. Time of cooling from 10 min up to 10 days. Time of measurement from 100 sec up to 3000 sec. Measurements were carried out on gamma spectrometer consisting of HPGe detector GC1518 and digital multichannel analyzer DSA-1000('Canberra', USA). Processing of the spectrometer information carried out with the help of software package Genie-2000. As a result of the carried out analyses we determine contents of 21 elements in

  12. Comparison of properties of silver-metal oxide electrical contact materials

    Directory of Open Access Journals (Sweden)

    Ćosović V.

    2012-01-01

    Full Text Available Changes in physical properties such as density, porosity, hardness and electrical conductivity of the Ag-SnO2 and Ag-SnO2In2O3 electrical contact materials induced by introduction of metal oxide nanoparticles were investigated. Properties of the obtained silver-metal oxide nanoparticle composites are discussed and presented in comparison to their counterparts with the micro metal oxide particles as well as comparable Ag-SnO2WO3 and Ag-ZnO contact materials. Studied silvermetal oxide composites were produced by powder metallurgy method from very fine pure silver and micro- and nanoparticle metal oxide powders. Very uniform microstructures were obtained for all investigated composites and they exhibited physical properties that are comparable with relevant properties of equivalent commercial silver based electrical contact materials. Both Ag-SnO2 and Ag- SnO2In2O3 composites with metal oxide nanoparticles were found to have lower porosity, higher density and hardness than their respective counterparts which can be attributed to better dispersion hardening i.e. higher degree of dispersion of metal oxide in silver matrix.

  13. Facility of aerosol filtration

    Energy Technology Data Exchange (ETDEWEB)

    Duverger de Cuy, G; Regnier, J

    1975-04-18

    Said invention relates to a facility of aerosol filtration, particularly of sodium aerosols. Said facility is of special interest for fast reactors where sodium fires involve the possibility of high concentrations of sodium aerosols which soon clog up conventional filters. The facility intended for continuous operation, includes at the pre-filtering stage, means for increasing the size of the aerosol particles and separating clustered particles (cyclone separator).

  14. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  15. Generation and characterization of biological aerosols for laser measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yung-Sung; Barr, E.B.

    1995-12-01

    Concerns for proliferation of biological weapons including bacteria, fungi, and viruses have prompted research and development on methods for the rapid detection of biological aerosols in the field. Real-time instruments that can distinguish biological aerosols from background dust would be especially useful. Sandia National Laboratories (SNL) is developing a laser-based, real-time instrument for rapid detection of biological aerosols, and ITRI is working with SNL scientists and engineers to evaluate this technology for a wide range of biological aerosols. This paper describes methods being used to generate the characterize the biological aerosols for these tests. In summary, a biosafe system has been developed for generating and characterizing biological aerosols and using those aerosols to test the SNL laser-based real-time instrument. Such tests are essential in studying methods for rapid detection of airborne biological materials.

  16. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  17. Atmospheric and aerosol chemistry

    International Nuclear Information System (INIS)

    McNeill, V. Faye; Ariya, Parisa A.; McGill Univ. Montreal, QC

    2014-01-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  18. Aerosols and Climate

    Indian Academy of Sciences (India)

    Large warming by elevated aerosols · AERONET – Global network (NASA) · Slide 25 · Slide 26 · Slide 27 · Slide 28 · Slide 29 · Slide 30 · Slide 31 · Long-term trends - Trivandrum · Enhanced warming over Himalayan-Gangetic region · Aerosol Radiative Forcing Over India _ Regional Aerosol Warming Experiment ...

  19. Aerosol fabrication methods for monodisperse nanoparticles

    Science.gov (United States)

    Jiang, Xingmao; Brinker, C Jeffrey

    2014-10-21

    Exemplary embodiments provide materials and methods for forming monodisperse particles. In one embodiment, the monodisperse particles can be formed by first spraying a nanoparticle-containing dispersion into aerosol droplets and then heating the aerosol droplets in the presence of a shell precursor to form core-shell particles. By removing either the shell layer or the nanoparticle core of the core-shell particles, monodisperse nanoparticles can be formed.

  20. Secondary organic aerosols from ozone-initiated reactions with emissions from wood-based materials and a ‘‘green’’ paint

    DEFF Research Database (Denmark)

    Toftum, Jørn; Freund, Sarah; Salthammer, Tunga

    2008-01-01

    This study examined the formation and growth of secondary organic aerosols (SOA) generated when ozone was added to a 1 m3 glass chamber that contained either pine shelving, oriented strand board (OSB), beech boards, or beach boards painted with an ‘‘eco’’ paint. The experiments were conducted...... dramatically; the mass concentration reached w15 mgm3 at w20 ppb O3, and w95 mgm3 at w40 ppb O3. The OSB emitted primarily limonene and a-pinene. Although the particle counts increased when O3 was introduced, the increase was not as large as anticipated based on the terpene concentrations. The beech boards...

  1. Interlanguage comparison of sport discourse (on the material of sport analytic article

    Directory of Open Access Journals (Sweden)

    Gavryushina Ekaterina Alexandrovna

    2016-06-01

    Full Text Available The article is devoted to the study of cultural and mental specificity of language units in the sport communication. The study was conducted on the material of English, Russian and German analytical articles, thematically related to tennis. Using the technique of cross-language comparison it is revealed significant characteristic parameters of sports discourse. The proposed comparative procedure consists in three stages of analysis: linguistic, cognitive-communicative and linguistic-cultural. During the analysis at each step there were identified certain criteria specific to the sport discourse in three linguasocieties. Sport communication reflects not only the specificity and originality of the language, but also the traditions, history, mentality, culture, and behavior patterns of modern professional sport community. Comparative study of sport discourse reveals the cultural, linguistic and cognitive features of sublanguage sports and allows to get a common view of the structure of sport analytical articles.

  2. Comparison of candidate materials for a synthetic osteo-odonto keratoprosthesis device.

    Science.gov (United States)

    Tan, Xiao Wei; Perera, A Promoda P; Tan, Anna; Tan, Donald; Khor, K A; Beuerman, Roger W; Mehta, Jodhbir S

    2011-01-05

    Osteo-odonto keratoprosthesis is one of the most successful forms of keratoprosthesis surgery for end-stage corneal and ocular surface disease. There is a lack of detailed comparison studies on the biocompatibilities of different materials used in keratoprosthesis. The aim of this investigation was to compare synthetic bioinert materials used for keratoprosthesis surgery with hydroxyapatite (HA) as a reference. Test materials were sintered titanium oxide (TiO(2)), aluminum oxide (Al(2)O(3)), and yttria-stabilized zirconia (YSZ) with density >95%. Bacterial adhesion on the substrates was evaluated using scanning electron microscopy and the spread plate method. Surface properties of the implant discs were scanned using optical microscopy. Human keratocyte attachment and proliferation rates were assessed by cell counting and MTT assay at different time points. Morphologic analysis and immunoblotting were used to evaluate focal adhesion formation, whereas cell adhesion force was measured with a multimode atomic force microscope. The authors found that bacterial adhesion on the TiO(2), Al(2)O(3), and YSZ surfaces were lower than that on HA substrates. TiO(2) significantly promoted keratocyte proliferation and viability compared with HA, Al(2)O(3,) and YSZ. Immunofluorescent imaging analyses, immunoblotting, and atomic force microscope measurement revealed that TiO(2) surfaces enhanced cell spreading and cell adhesion compared with HA and Al(2)O(3). TiO(2) is the most suitable replacement candidate for use as skirt material because it enhanced cell functions and reduced bacterial adhesion. This would, in turn, enhance tissue integration and reduce device failure rates during keratoprosthesis surgery.

  3. PM 2.5 mass concentrations in comparison with aerosol optical depths over the Arabian Sea and Indian Ocean during winter monsoon

    Science.gov (United States)

    Ramachandran, S.

    An analysis of PM 2.5 mass concentrations and 0.5 μm aerosol optical depths (AODs) during the Northeast winter monsoon seasons of 1996-2000 is performed and intercompared. AODs are found to show diurnal variations over Coastal India (CI) (west coast) while they are relatively smooth over the Arabian Sea (AS) (5-20°N) and tropical Indian Ocean (TIO) (5°N-20°S). PM 2.5, PM 10 and total mass concentrations show less variations in a day over these oceanic regions. Columnar AODs are found to increase with an increase in the marine boundary layer aerosol concentrations over CI and AS while an opposite trend is seen over TIO. The yearly-mean AODs and mass concentrations are found to increase over CI and AS, over TIO the mass concentrations increased while the AODs decreased during 1996-2000. It is found from the 7-days air back trajectory analyses that at different altitudes air masses can originate from different source regions leading to changes in chemical, physical and optical characteristics of the aerosol between the surface and column. The differences in the surface and columnar measurements could also occur due to changes in the meteorological conditions, wind patterns, in addition to changes in production and subsequently the transport of aerosols. Least-squares fits to the above intercomparison resulted in intercepts of 0.24 and 0.22 over CI and AS indicating that the background AODs over these oceanic regions are higher. An examination of the daily-mean wind speeds and PM 2.5 mass concentrations yielded an index of wind dependence of 0.04 for AS and 0.07 for TIO. The background PM 2.5 mass concentrations are also found to be high at 36 and 25 μg m -3 over AS and TIO, respectively, indicating a stronger influence from the continent. Frequency distribution figures show that 28% of the PM 2.5 values over CI lie in the 60-80 μg m -3 range. Over AS the dominant mode of distribution is 40-60 μg m -3 with a peak value of 42%. Over TIO PM 2.5 values are found to

  4. New particle formation in the sulfuric acid–dimethylamine–water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

    Directory of Open Access Journals (Sweden)

    A. Kürten

    2018-01-01

    Full Text Available A recent CLOUD (Cosmics Leaving OUtdoor Droplets chamber study showed that sulfuric acid and dimethylamine produce new aerosols very efficiently and yield particle formation rates that are compatible with boundary layer observations. These previously published new particle formation (NPF rates are reanalyzed in the present study with an advanced method. The results show that the NPF rates at 1.7 nm are more than a factor of 10 faster than previously published due to earlier approximations in correcting particle measurements made at a larger detection threshold. The revised NPF rates agree almost perfectly with calculated rates from a kinetic aerosol model at different sizes (1.7 and 4.3 nm mobility diameter. In addition, modeled and measured size distributions show good agreement over a wide range of sizes (up to ca. 30 nm. Furthermore, the aerosol model is modified such that evaporation rates for some clusters can be taken into account; these evaporation rates were previously published from a flow tube study. Using this model, the findings from the present study and the flow tube experiment can be brought into good agreement for the high base-to-acid ratios (∼ 100 relevant for this study. This confirms that nucleation proceeds at rates that are compatible with collision-controlled (a.k.a. kinetically controlled NPF for the conditions during the CLOUD7 experiment (278 K, 38 % relative humidity, sulfuric acid concentration between 1  ×  106 and 3  ×  107 cm−3, and dimethylamine mixing ratio of ∼  40 pptv, i.e., 1  ×  109 cm−3.

  5. New particle formation in the sulfuric acid-dimethylamine-water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

    Science.gov (United States)

    Kürten, Andreas; Li, Chenxi; Bianchi, Federico; Curtius, Joachim; Dias, António; Donahue, Neil M.; Duplissy, Jonathan; Flagan, Richard C.; Hakala, Jani; Jokinen, Tuija; Kirkby, Jasper; Kulmala, Markku; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Onnela, Antti; Rissanen, Matti P.; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Tröstl, Jasmin; Ye, Penglin; McMurry, Peter H.

    2018-01-01

    A recent CLOUD (Cosmics Leaving OUtdoor Droplets) chamber study showed that sulfuric acid and dimethylamine produce new aerosols very efficiently and yield particle formation rates that are compatible with boundary layer observations. These previously published new particle formation (NPF) rates are reanalyzed in the present study with an advanced method. The results show that the NPF rates at 1.7 nm are more than a factor of 10 faster than previously published due to earlier approximations in correcting particle measurements made at a larger detection threshold. The revised NPF rates agree almost perfectly with calculated rates from a kinetic aerosol model at different sizes (1.7 and 4.3 nm mobility diameter). In addition, modeled and measured size distributions show good agreement over a wide range of sizes (up to ca. 30 nm). Furthermore, the aerosol model is modified such that evaporation rates for some clusters can be taken into account; these evaporation rates were previously published from a flow tube study. Using this model, the findings from the present study and the flow tube experiment can be brought into good agreement for the high base-to-acid ratios (˜ 100) relevant for this study. This confirms that nucleation proceeds at rates that are compatible with collision-controlled (a.k.a. kinetically controlled) NPF for the conditions during the CLOUD7 experiment (278 K, 38 % relative humidity, sulfuric acid concentration between 1 × 106 and 3 × 107 cm-3, and dimethylamine mixing ratio of ˜ 40 pptv, i.e., 1 × 109 cm-3).

  6. Computational modeling and experimental characterization of indoor aerosol transport

    International Nuclear Information System (INIS)

    Konecni, Snezana; Whicker, Jeffrey J.; Martin, Richard A.

    2002-01-01

    When a hazardous aerosol or gas is inadvertently or deliberately released in an occupied facility, the airborne material presents a hazard to people. Inadvertent accidents and exposures continue to occur in Los Alamos and other nuclear facilities despite state-of-art engineering and administrative controls, and heightened diligence. Despite the obvious need in occupational settings and for homeland defense, the body of research in hazardous aerosol dispersion and control in large, complex, ventilated enclosures is extremely limited. The science governing generation, transport, inhalation, and detection of airborne hazards is lacking and must be developed to where it can be used by engineers or safety professionals in the prediction of worker exposure, in the prevention of accidents, or in the mitigation of terrorist actions. In this study, a commercial computational fluid dynamics (CFD) code, CFX5.4, and experiments were used to assess flow field characteristics, and to investigate aerosol release and transport in a large, ventilated workroom in a facility at Savannah River Site. Steady state CFD results illustrating a complex, ventilation-induced, flow field with vortices, velocity gradients, and quiet zones are presented, as are time-dependent CFD and experimental aerosol dispersion results. The comparison of response times between CFD and experimental results was favorable. It is believed that future applications of CFD and experiments can have a favorable impact on the design of ventilation (HVAC) systems and worker safety with consideration to facility costs. Ultimately, statistical methods will be used in conjunction with CFD calculations to determine the optimal number and location of detectors, as well as optimal egress routes in event of a release.

  7. Containment aerosol behaviour simulation studies in the BARC nuclear aerosol test facility

    International Nuclear Information System (INIS)

    Mayya, Y.S.; Sapra, B.K.; Khan, Arshad; Sunny, Faby; Nair, R.N.; Raghunath, Radha; Tripathi, R.M.; Markandeya, S.G.; Puranik, V.D.; Ghosh, A.K.; Kushwaha, H.S.; Shreekumar, K.P.; Padmanabhan, P.V.A.; Murthy, P.S.S.; Venlataramani, N.

    2005-02-01

    A Nuclear Aerosol Test Facility (NATF) has been built and commissioned at Bhabha Atomic Research Centre to carry out simulation studies on the behaviour of aerosols released into the reactor containment under accident conditions. This report also discusses some new experimental techniques for estimation of density of metallic aggregates. The experimental studies have shown that the dynamic densities of aerosol aggregates are far lower than their material densities as expected by the well-known fractal theory of aggregates. In the context of codes, this has significant bearing in providing a mechanistic basis for the input density parameter used in estimating the aerosol evolution characteristics. The data generated under the quiescent and turbulent conditions and the information on aggregate densities are now being subjected to the validation of the aerosol behaviour codes. (author)

  8. Solubility of plutonium dioxide aerosols, in vitro

    International Nuclear Information System (INIS)

    Newton, G.J.; Kanapilly, G.M.

    1976-01-01

    Solubility of plutonium aerosols is an important parameter in establishing risk estimates for industrial workers who might accidentally inhale these materials and in evaluating environmental health impacts associated with Pu. In vitro solubility of industrial plutonium aerosols in a simulated lung fluid is compared to similar studies with ultrafine aerosols from laser ignition of delta phase plutonium metal and laboratory-produced spherical particles of 238 PuO 2 and 239 PuO 2 . Although relatively insoluble, industrial plutonium-mixed oxide aerosols were much more soluble than laboratory-produced plutonium dioxide particles. Chain agglomerate aerosols from laser ignition of metallic Pu indicated in vitro dissolution half-times of 10 and 50 days for activity median aerodynamic diameter (AMAD) of 0.7 and 2.3 μm, respectively. Plutonium-containing mixed oxide aerosols indicated dissolution half-times of 40 to 500 days for particles formed by industrial powder comminution and blending. Centerless grinding of fuel pellets yielded plutonium-containing aerosols with dissolution half-times of 1200 to 8000 days. All mixed oxide particles were in the size range 1.0 μm to 2.5 μm AMAD

  9. Comparison of the trace analysis of heavy metal aerosols by means of atom absorption spectroscopy and proton-induced X-ray spectrometry

    International Nuclear Information System (INIS)

    Nottrodt, K.H.; Georgii, H.W.; Groeneveld, K.O.; Frankfurt Univ.

    1977-01-01

    The comparative analyses of AAS and PIXE (Proton-Induced X-ray Emission) show very good agreement in the absolute values of the concentrations of all metals analyzed. The practical detection limits are about 10 -10 g for the investigated element in both measuring processes, so that the analysis of pure air samples is possible with both methods. PIXE is particularly suitable for the analysis of aerosol samples as it is not necessary to process the filter, the samples are not destroyed, and many elements can be simultaneously analyzed within a short time (5-10 min.). Furthermore, the possibility of automatization enables an efficient treatment of meteorological problems. (orig.) [de

  10. Synthesis and comparison of the activities of a catalyst supported on two silicate materials

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Eduardo G., E-mail: eduardogv5007@gmail.com [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Silva, Rafael O.; Carmo, Devaney R. do [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Junior, Enes F. [Departamento de Fitotecnia, Tecnologia de Alimentos e Sócio Economia, Faculdade de Engenharia de Ilha Solteira, Universidade Estadual Paulista, Ilha Solteira, São Paulo (Brazil); Dias Filho, Newton L., E-mail: nldias@unesc.net [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Universidade do Extremo Sul Catarinense, Av. Universitaria, 1105, CP 3167, CEP 88806-000, Criciúma, SC (Brazil)

    2017-04-15

    The focus of this work is inspecting the synthesis and comparison of the activities of a catalyst supported on two silicate materials in the epoxidation of 1-octene. The two new catalyst materials were characterized by infrared spectroscopy, elemental analysis, solid-state {sup 29}Si and {sup 13}C nuclear magnetic resonance, scanning electronic microscope (SEM) and analysis of nitrogen. Lastly, the two new catalysts, Silsesq-TCA-[(W(CO){sub 3}I{sub 2}){sub 3}] and Silica-TCA-[W(CO){sub 3}I{sub 2}] were tested as catalysts in reactions of epoxidation of 1-octene and compared with their analogue not supported [W(CO){sub 3}I{sub 2}(thiocarbamide)]. After an extensive literature search, we verified that our work is the first that has reported the immobilization process of [W(CO){sub 3}I{sub 2}(NCCH{sub 3}){sub 2}] on silsesquioxane and silica gel functionalized with propyl-thiocarbamide groups and their applications as catalysts of reactions of catalytic epoxidation of 1-octene. - Highlights: • Immobilization of [W(CO){sub 3}I{sub 2}(NCCH{sub 3}){sub 2}] complex onto mesoporous supports. • Synthesis and characterization of new mesoporous catalysts. • The new catalysts exhibit great catalytic activity in the epoxidation of 1-octene. • Recyclable catalysts with excellent reusability and stability.

  11. Comparison of infrared and 3D digital image correlation techniques applied for mechanical testing of materials

    Science.gov (United States)

    Krstulović-Opara, Lovre; Surjak, Martin; Vesenjak, Matej; Tonković, Zdenko; Kodvanj, Janoš; Domazet, Željko

    2015-11-01

    To investigate the applicability of infrared thermography as a tool for acquiring dynamic yielding in metals, a comparison of infrared thermography with three dimensional digital image correlation has been made. Dynamical tension tests and three point bending tests of aluminum alloys have been performed to evaluate results obtained by IR thermography in order to detect capabilities and limits for these two methods. Both approaches detect pastification zone migrations during the yielding process. The results of the tension test and three point bending test proved the validity of the IR approach as a method for evaluating the dynamic yielding process when used on complex structures such as cellular porous materials. The stability of the yielding process in the three point bending test, as contrary to the fluctuation of the plastification front in the tension test, is of great importance for the validation of numerical constitutive models. The research proved strong performance, robustness and reliability of the IR approach when used to evaluate yielding during dynamic loading processes, while the 3D DIC method proved to be superior in the low velocity loading regimes. This research based on two basic tests, proved the conclusions and suggestions presented in our previous research on porous materials where middle wave infrared thermography was applied.

  12. Aerosols on the surface of needles in the vicinity of Winterthur

    International Nuclear Information System (INIS)

    Wyttenbach, A.; Tobler, L.; Bajo, S.

    1991-01-01

    The composition and the mass of aerosols residing on the surface of one-year-old needles of Norway spruce are described. The composition of aerosols on spruce needles is compared with that of aerosols collected by air filters and the composition of the local soil. A comparison of the years 1982 and 1985 shows virtually identical conditions. Finally, possible connections between aerosol mass and inherent needle content are discussed. (author) 5 figs., 2 tabs., 13 refs

  13. Light-Absorbing Aerosol during NASA GRIP: Overview of Observations in the Free Troposphere and Associated with Tropical Storm Systems

    Science.gov (United States)

    Ziemba, L. D.; Beyersdorf, A. J.; Chen, G.; Corr, C. A.; Craig, L.; Dhaniyala, S.; Dibb, J. E.; Hudgins, C. H.; Ismail, S.; Latham, T.; Nenes, A.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

    2010-12-01

    Aerosols play a significant role in regulating Earth’s climate. Absorbing aerosols typically constitute a small fraction of ambient particle mass but can contribute significantly to direct and indirect climate forcing depending on size, mixing state, concentration, chemical composition, and vertical and spatial distribution. Aerosols may also significantly affect tropical storm/hurricane dynamics through direct light absorption and activation as cloud nuclei. An extensive suite of instrumentation measuring aerosol chemical, physical, and optical properties was deployed aboard the NASA DC-8 to characterize aerosol during the NASA GRIP (Genesis and Rapid Intensification Processes; August-September 2010) mission. The majority of flight time was spent at high altitude (greater than 9 km) and thus much of the sampling was done in the free troposphere, including extensive sampling in the vicinity of tropical storm systems and more diffuse cirrus clouds. With operations based in Fort Lauderdale, FL and St. Croix, U.S. Virgin Islands, a large geographic region was sampled including much of the Gulf of Mexico and tropical Atlantic Ocean. Observations are reported for light-absorbing carbon aerosol (mainly black carbon, BC) primarily using a single particle soot photometer (SP2). The SP2 employs single-particle laser-induced incandescence to provide a mass-specific measurement not subject to scattering interference that is optimal for the low concentration environments like those encountered during GRIP. BC mass concentrations, 100-500 nm size distributions, and mixing state (i.e. coating thickness of scattering material) are presented. Total and sub-micron aerosol absorption coefficients (principally from BC and dust aerosol) are reported using a particle soot absorption photometer (PSAP) along with comparisons with calculated absorption coefficients derived from SP2 observations in various conditions. In addition, dust aerosol is specifically identified using optical and

  14. Impact of Aerosol Processing on Orographic Clouds

    Science.gov (United States)

    Pousse-Nottelmann, Sara; Zubler, Elias M.; Lohmann, Ulrike

    2010-05-01

    . [6]. Our investigation regarding the influence of aerosol processing will focus on the regional scale using a cloud-system resolving model with a much higher resolution. Emphasis will be placed on orographic mixed-phase precipitation. Different two-dimensional simulations of idealized orographic clouds will be conducted to estimate the effect of aerosol processing on orographic cloud formation and precipitation. Here, cloud lifetime, location and extent as well as the cloud type will be of particular interest. In a supplementary study, the new parameterization will be compared to observations of total and interstitial aerosol concentrations and size distribution at the remote high alpine research station Jungfraujoch in Switzerland. In addition, our simulations will be compared to recent simulations of aerosol processing in warm, mixed-phase and cold clouds, which have been carried out at the location of Jungfraujoch station [5]. References: [1] Pruppacher & Jaenicke (1995), The processing of water vapor and aerosols by atmospheric clouds, a global estimate, Atmos. Res., 38, 283295. [2] Seifert & Beheng (2006), A two-moment microphysics parameterization for mixed-phase clouds. Part 1: Model description, Meteorol. Atmos. Phys., 92, 4566. [3] Vignati et al. (2004), An efficient size-resolved aerosol microphysics module for large-scale transport models, J. Geophys. Res., 109, D22202 [4] Muhlbauer & Lohmann (2008), Sensitivity studies of the role of aerosols in warm-phase orographic precipitation in different flow regimes, J. Atmos. Sci., 65, 25222542. [5] Hoose et al. (2008), Aerosol processing in mixed-phase clouds in ECHAM5HAM: Model description and comparison to observations, J. Geophys. Res., 113, D071210. [6] Hoose et al. (2008), Global simulations of aerosol processing in clouds, Atmos. Chem. Phys., 8, 69396963.

  15. Orientation-dependent low field magnetic anomalies and room-temperature spintronic material – Mn doped ZnO films by aerosol spray pyrolysis

    CSIR Research Space (South Africa)

    Nkosi, SS

    2013-12-01

    Full Text Available of ferromagnetism, a relatively new phenomenon called “low-field microwave absorption” has been observed in ferromagnetic materials and other various materials such as high temperature superconductors, ferrites, manganites, doped silicate glasses and soft... absorption phenomenon has been observed in ferromagnetic materials and various other materials such as superconductors, ferrites, manganites, semiconductors, doped silicate glasses, in soft materials and recently in iron monosilicides films [41- 46...

  16. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    to carbonyl- and nitro- functional groups on conjugated and aromatic organic structures (e.g. PAH, and terpene derived products). Using 12-hour fine (0.1-1.0 micron) aerosol samples collected in the field on quartz filters, uv/vis and infrared spectra were obtained in the laboratory using integrating spheres and diffuse reflectance spectroscopy, respectively. An inter-comparison of the "real-time" measurements made by the photo-acoustic, aethalometer and MAAP techniques have been described. In addition, the in situ aethalometer (seven-channel) results are compared with continuous integrating sphere uv-visible spectra to examine the angstrom absorption coefficient variance. These results will be briefly overviewed and the specific posters detailing these results will be highlighted highlighted. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City under the support of the Atmospheric Science Program. "This researchwas supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-07ER64329.

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

    Science.gov (United States)

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

    2017-12-01

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

  18. Filtration of sodium-fire aerosols

    International Nuclear Information System (INIS)

    Alexas, A.; Jordan, S.; Lindner, W.

    1979-01-01

    Different filter devices have been developed and tested with respect to their use in the off-gas system of liquid-metal fast breeder reactors to prevent the escape of sodium-fire aerosols that might be formed in case of an accident. The testing results have shown that the use of a multilayer sand bed filter is still the best method to filter limited amounts of sodium-fire aerosols over a long operating time. Efficiencies on the order of 99.98 and 98.8% were reached for loading capacities of 500 and 1000 g/m 2 , respectively. Unlimited amounts of sodium-fire aerosols can be filtered by wet scrubbers with an efficiency of 70% per scrubber stage. Fiberglas filters connot be used for the filtration of sodium-fire aerosols over a long operating time because the filter material can be destroyed after several days of operating

  19. MATRIX (Multiconfiguration Aerosol TRacker of mIXing state: an aerosol microphysical module for global atmospheric models

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2008-10-01

    Full Text Available A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS climate model (ModelE are described. This module, which is based on the quadrature method of moments (QMOM, represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations.

    A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment

  20. Aerosol behaviour modeling and measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gieseke, J A; Reed, L D [Batelle Memorial Institute, Columbus, OH (United States)

    1977-01-01

    Aerosol behavior within Liquid Metal Fast Breeder Reactor (LMFBR) containments is of critical importance since most of the radioactive species are expected to be associated with particulate forms and the mass of radiologically significant material leaked to the ambient atmosphere is directly related to the aerosol concentration airborne within the containment. Mathematical models describing the behavior of aerosols in closed environments, besides providing a direct means of assessing the importance of specific assumptions regarding accident sequences, will also serve as the basic tool with which to predict the consequences of various postulated accident situations. Consequently, considerable efforts have been recently directed toward the development of accurate and physically realistic theoretical aerosol behavior models. These models have accounted for various mechanisms affecting agglomeration rates of airborne particulate matter as well as particle removal rates from closed systems. In all cases, spatial variations within containments have been neglected and a well-mixed control volume has been assumed. Examples of existing computer codes formulated from the mathematical aerosol behavior models are the Brookhaven National Laboratory TRAP code, the PARDISEKO-II and PARDISEKO-III codes developed at Karlsruhe Nuclear Research Center, and the HAA-2, HAA-3, and HAA-3B codes developed by Atomics International. Because of their attractive short computation times, the HAA-3 and HAA-3B codes have been used extensively for safety analyses and are attractive candidates with which to demonstrate order of magnitude estimates of the effects of various physical assumptions. Therefore, the HAA-3B code was used as the nucleus upon which changes have been made to account for various physical mechanisms which are expected to be present in postulated accident situations and the latest of the resulting codes has been termed the HAARM-2 code. It is the primary purpose of the HAARM

  1. Verification, improvement and application of aerosol optical depths in China Part 1: Inter-comparison of NPP-VIIRS and Aqua-MODIS

    Science.gov (United States)

    Wei, Jing; Sun, Lin; Huang, Bo; Bilal, Muhammad; Zhang, Zhaoyang; Wang, Lunche

    2018-02-01

    The objective of this study is to evaluate typical aerosol optical depth (AOD) products in China, which experienced seriously increasing atmospheric particulate pollution. For this, the Aqua-MODerate resolution Imaging Spectroradiometer (MODIS) AOD products (MYD04) at 10 km spatial resolution and Visible Infrared Imaging Radiometer Suite (VIIRS) Environmental Data Record (EDR) AOD product at 6 km resolution for different Quality Flags (QF) are obtained for validation against AErosol RObotic NETwork (AERONET) AOD measurements during 2013-2016. Results show that VIIRS EDR similarly Dark Target (DT) and MODIS DT algorithms perform worse with only 45.36% and 45.59% of the retrievals (QF = 3) falling within the Expected Error (EE, ±(0.05 + 15%)) compared to the Deep Blue (DB) algorithm (69.25%, QF ≥ 2). The DT retrievals perform poorly over the Beijing-Tianjin-Hebei (BTH) and Yangtze-River-Delta (YRD) regions, which significantly overestimate the AOD observations, but the performance is better over the Pearl-River-Delta (PRD) region than DB retrievals, which seriously under-estimate the AOD loadings. It is not surprising that the DT algorithm performs better over vegetated areas, while the DB algorithm performs better over bright areas mainly depends on the accuracy of surface reflectance estimation over different land use types. In general, the sensitivity of aerosol to apparent reflectance reduces by about 34% with an increasing surface reflectance by 0.01. Moreover, VIIRS EDR and MODIS DT algorithms perform overall better in the winter as 64.53% and 72.22% of the retrievals are within the EE but with less retrievals. However, the DB algorithm performs worst (57.17%) in summer mainly affected by the vegetation growth but there are overall high accuracies with more than 62% of the collections falling within the EE in other three seasons. Results suggest that the quality assurance process can help improve the overall data quality for MYD04 DB retrievals, but it is

  2. Spectrophotometric Evaluation of Polyetheretherketone (PEEK as a Core Material and a Comparison with Gold Standard Core Materials

    Directory of Open Access Journals (Sweden)

    Bogna Stawarczyk

    2016-06-01

    Full Text Available This study investigated the colorimetric properties of different veneering materials on core materials. Standardized specimens (10 mm × 10 mm × 1.5 mm reflecting four core (polyetheretherketone (PEEK, zirconia (ZrO2, cobalt–chromium–molybdenum alloy (CoCrMo, and titanium oxide (TiO2; thickness: 1.5 mm and veneering materials (VITA Mark II, IPS e.max CAD, LAVA Ultimate and VITA Enamic, all in shade A3; thickness: 0.5, 1.0, 1.5 and 2 mm, respectively were fabricated. Specimens were superimposed to assemblies, and the color was determined with a spectrophotometer (CieLab-System or a chair-side color measurement device (VITA EasyShade, respectively. Data were analyzed using three-, two-, and one-way ANOVA, a Chi2-test, and a Wilson approach (p < 0.05. The measurements with EasyShade showed A2 for VITA Mark II, A3.5 for VITA Enamic, B2 for LAVA Ultimate, and B3 for IPS e.max CAD. LabE-values showed significant differences between the tested veneering materials (p < 0.001. CieLab-System and VITA EasyShade parameters of the different assemblies showed a significant impact of core (p < 0.001, veneering material (p < 0.001, and thickness of the veneering material (p < 0.001. PEEK as core material showed comparable outcomes as compared to ZrO2 and CoCrMo, with respect to CieLab-System parameters for each veneering material. The relative frequency of the measured VITA EasyShade parameters regarding PEEK cores also showed comparable results as compared to the gold standard CoCrMo, regardless of the veneering material used.

  3. A comparison between tracer gas and aerosol particles distribution indoors: The impact of ventilation rate, interaction of airflows, and presence of objects

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Ondráček, Jakub; Melikov, Arsen Krikor

    2017-01-01

    for the exposure to all different-sized test particles. A change in the ventilation rate did not affect the difference in concentration distribution between tracer gas and larger particle sizes. Increasing the room surface area did not influence the similarity in the dispersion of the aerosol particles...... room with mixing ventilation. Three layouts were arranged: an empty room, an office room with an occupant sitting in front of a table, and a single-bed hospital room. The room occupant was simulated by a thermal manikin. Monodisperse particles of three sizes (0.07, 0.7, and 3.5 μm) and nitrous oxide...... tracer gas were generated simultaneously at the same location in the room. The particles and gas concentrations were measured in the bulk room air, in the breathing zone of the manikin, and in the exhaust air. Within the breathing zone of the sitting occupant, the tracer gas emerged as reliable predictor...

  4. A comparison between PIXE and ICP-AES measurements of metals in aerosol particulate collected in urban and marine sites in Italy

    Energy Technology Data Exchange (ETDEWEB)

    Traversi, R.; Becagli, S. [Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, I-50019 Sesto F.no, Florence (Italy); Calzolai, G.; Chiari, M.; Giannoni, M. [Department of Physics and Astronomy, University of Florence and I.N.F.N., Florence, Via G. Sansone 1, I-50019 Sesto F.no, Florence (Italy); Lucarelli, F., E-mail: lucarelli@fi.infn.it [Department of Physics and Astronomy, University of Florence and I.N.F.N., Florence, Via G. Sansone 1, I-50019 Sesto F.no, Florence (Italy); Nava, S. [Department of Physics and Astronomy, University of Florence and I.N.F.N., Florence, Via G. Sansone 1, I-50019 Sesto F.no, Florence (Italy); Rugi, F.; Severi, M.; Udisti, R. [Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, I-50019 Sesto F.no, Florence (Italy)

    2014-01-01

    PIXE and ICP-AES techniques are largely used in atmospheric aerosol studies. Since PIXE is able to provide the total elemental concentrations, while ICP-AES results depend on the extraction conditions, parallel PIXE and ICP-AES measurements of Fe, Al, Cu, Pb, Mn, Cr, Ni, V, As on PM10 and PM2.5 samples were compared. Two extraction procedures were applied to samples from 5 sites at different anthropization level in Italy: a “weak” extraction (HNO{sub 3} at pH = 1.5) and a “strong” extraction (micro-wave oven in HNO{sub 3} and H{sub 2}O{sub 2} – following EU rules). The amount of the metal extracted in the different conditions resulted to be strongly dependent on the sampling site, on the main sources of the particle (crustal or anthropic) containing the metal and on the sampled size class.

  5. Whole-body nanoparticle aerosol inhalation exposures.

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L; Stapleton, Phoebe A; Minarchick, Valerie C; Nurkiewicz, Timothy R

    2013-05-07

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size (6), which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria (5). A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m(3) whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm(3)) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m(3)). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpre and Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is sampling flowrate (m(3)/min), and t is the sampling

  6. Analyses of CsI aerosol deposition in aerosol behavior tests in WIND project

    International Nuclear Information System (INIS)

    Kudo, Tamotsu; Shibazaki, Hiroaki; Hidaka, Akihide

    1999-01-01

    The aerosol deposition tests have been performed in WIND project at JAERI to characterize the aerosol behavior. The aerosol deposition tests named WAV1-D and WAV2-D were analyzed by aerosol behavior analysis codes, JAERI's ART and SNL's VICTORIA. The comparison calculation was performed for the confirmation of the analytical capabilities of the both codes and improvement of the models in ART. The deposition mass calculated by ART was larger than that by VICTORIA. This discrepancy is caused by differences in model for FP vapor condensation onto the wall surface. In the WAV2-D test, in which boric acid was placed on the floor area of the test section prior to the deposition phase to simulate the PWR primary coolant, there was a discrepancy in deposition mass between analytical results in both codes and experimental results. The discrepancy may be caused by existence of boric acid which is not considered in the codes. (author)

  7. Radioactive aerosols. [In Russian

    Energy Technology Data Exchange (ETDEWEB)

    Natanson, G L

    1956-01-01

    Tabulations are given presenting various published data on safe atmospheric concentrations of various radioactive and non-radioactive aerosols. Methods of determination of active aerosol concentrations and dispersion as well as the technical applications of labeled aerosols are discussed. The effect of atomic explosions are analyzed considering the nominal atomic bomb based on /sup 235/U and /sup 232/Pu equivalent to 20,000 tons of TNT.

  8. Aerosols CFA 97

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    During the thirteen congress on aerosols several papers were presented about the behaviour of radioactive aerosols and their impact on environment, or the exposure to radon and to its daughters, the measurement of the size of the particulates of the short-lived radon daughters and two papers about the behaviour of aerosols in containment during a fission products release in the primary circuit and susceptible to be released in atmosphere in the case of containment failure. (N.C.)

  9. Cloud condensation nuclei activity of aliphatic amine secondary aerosol

    Science.gov (United States)

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The resulting particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate ...

  10. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  11. Carbonaceous aerosol particles from common vegetation in the Grand Canyon

    International Nuclear Information System (INIS)

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

    1992-05-01

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

  12. The Two-Column Aerosol Project: Phase I—Overview and impact of elevated aerosol layers on aerosol optical depth

    Science.gov (United States)

    Berg, Larry K.; Fast, Jerome D.; Barnard, James C.; Burton, Sharon P.; Cairns, Brian; Chand, Duli; Comstock, Jennifer M.; Dunagan, Stephen; Ferrare, Richard A.; Flynn, Connor J.; Hair, Johnathan W.; Hostetler, Chris A.; Hubbe, John; Jefferson, Anne; Johnson, Roy; Kassianov, Evgueni I.; Kluzek, Celine D.; Kollias, Pavlos; Lamer, Katia; Lantz, Kathleen; Mei, Fan; Miller, Mark A.; Michalsky, Joseph; Ortega, Ivan; Pekour, Mikhail; Rogers, Ray R.; Russell, Philip B.; Redemann, Jens; Sedlacek, Arthur J.; Segal-Rosenheimer, Michal; Schmid, Beat; Shilling, John E.; Shinozuka, Yohei; Springston, Stephen R.; Tomlinson, Jason M.; Tyrrell, Megan; Wilson, Jacqueline M.; Volkamer, Rainer; Zelenyuk, Alla; Berkowitz, Carl M.

    2016-01-01

    The Two-Column Aerosol Project (TCAP), conducted from June 2012 through June 2013, was a unique study designed to provide a comprehensive data set that can be used to investigate a number of important climate science questions, including those related to aerosol mixing state and aerosol radiative forcing. The study was designed to sample the atmosphere between and within two atmospheric columns; one fixed near the coast of North America (over Cape Cod, MA) and a second moveable column over the Atlantic Ocean several hundred kilometers from the coast. The U.S. Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) was deployed at the base of the Cape Cod column, and the ARM Aerial Facility was utilized for the summer and winter intensive observation periods. One important finding from TCAP is that four of six nearly cloud-free flight days had aerosol layers aloft in both the Cape Cod and maritime columns that were detected using the nadir pointing second-generation NASA high-spectral resolution lidar (HSRL-2). These layers contributed up to 60% of the total observed aerosol optical depth (AOD). Many of these layers were also intercepted by the aircraft configured for in situ sampling, and the aerosol in the layers was found to have increased amounts of biomass burning material and nitrate compared to aerosol found near the surface. In addition, while there was a great deal of spatial and day-to-day variability in the aerosol chemical composition and optical properties, no systematic differences between the two columns were observed.

  13. The Two-Column Aerosol Project: Phase I - Overview and Impact of Elevated Aerosol Layers on Aerosol Optical Depth

    Science.gov (United States)

    Berg, Larry K.; Fast, Jerome D.; Barnard, James C.; Burton, Sharon P.; Cairns, Brian; Chand, Duli; Comstock, Jennifer M.; Dunagan, Stephen; Ferrare, Richard A.; Flynn, Connor J.; hide

    2015-01-01

    The Two-Column Aerosol Project (TCAP), conducted from June 2012 through June 2013, was a unique study designed to provide a comprehensive data set that can be used to investigate a number of important climate science questions, including those related to aerosol mixing state and aerosol radiative forcing. The study was designed to sample the atmosphere be tween and within two atmospheric columns; one fixed near the coast of North America (over Cape Cod, MA) and a second moveable column over the Atlantic Ocean several hundred kilometers from the coast. The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) was deployed at the base of the Cape Cod column, and the ARM Aerial Facility was utilized for the summer and winter intensive observation periods. One important finding from TCAP is that four of six nearly cloud-free flight days had aerosol layers aloft in both the Cape Cod and maritime columns that were detected using the nadir pointing second-generation NASA high-spectral resolution lidar (HSRL-2).These layer s contributed up to 60 of the total observed aerosol optical depth (AOD). Many of these layers were also intercepted by the aircraft configured for in situ sampling, and the aerosol in the layers was found to have increased amounts of biomass burning material and nitrate compared to aerosol found near the surface. In addition, while there was a great deal of spatial and day-to-day variability in the aerosol chemical composition and optical properties, no systematic differences between the two columns were observed.

  14. Devices and methods for generating an aerosol

    KAUST Repository

    Bisetti, Fabrizio; Scribano, Gianfranco

    2016-01-01

    Aerosol generators and methods of generating aerosols are provided. The aerosol can be generated at a stagnation interface between a hot, wet stream and a cold, dry stream. The aerosol has the benefit that the properties of the aerosol can

  15. Development of a fission product transport module predicting the behavior of radiological materials during sever accidents in a nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyung Seok; Rhee, Bo Wook; Kim, Dong Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-09-15

    Korea Atomic Energy Research Institute is developing a fission product transport module for predicting the behavior of radioactive materials in the primary cooling system of a nuclear power plant as a separate module, which will be connected to a severe accident analysis code, Core Meltdown Progression Accident Simulation Software (COMPASS). This fission product transport (COMPASS-FP) module consists of a fission product release model, an aerosol generation model, and an aerosol transport model. In the fission product release model there are three submodels based on empirical correlations, and they are used to simulate the fission product gases release from the reactor core. In the aerosol generation model, the mass conservation law and Raoult's law are applied to the mixture of vapors and droplets of the fission products in a specified control volume to find the generation of the aerosol droplet. In the aerosol transport model, empirical correlations available from the open literature are used to simulate the aerosol removal processes owing to the gravitational settling, inertia impaction, diffusiophoresis, and thermophoresis. The COMPASS-FP module was validated against Aerosol Behavior Code Validation and Evaluation (ABCOVE-5) test performed by Hanford Engineering Development Laboratory for comparing the prediction and test data. The comparison results assuming a non-spherical aerosol shape for the suspended aerosol mass concentration showed a good agreement with an error range of about ±6%. It was found that the COMPASS-FP module produced the reasonable results of the fission product gases release, the aerosol generation, and the gravitational settling in the aerosol removal processes for ABCOVE-5. However, more validation for other aerosol removal models needs to be performed.

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

    Science.gov (United States)

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

    2013-01-01

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

  17. Methodology comparison for gamma-heating calculations in material-testing reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, M.; Vaglio-Gaudard, C.; Lyoussi, A. [CEA, DEN, DER, Cadarache F-13108 Saint Paul les Durance (France); Reynard-Carette, C. [Aix Marseille Universite, CNRS, Universite de Toulon, IM2NP UMR 7334, 13397, Marseille (France)

    2015-07-01

    The Jules Horowitz Reactor (JHR) is a Material-Testing Reactor (MTR) under construction in the south of France at CEA Cadarache (French Alternative Energies and Atomic Energy Commission). It will typically host about 20 simultaneous irradiation experiments in the core and in the beryllium reflector. These experiments will help us better understand the complex phenomena occurring during the accelerated ageing of materials and the irradiation of nuclear fuels. Gamma heating, i.e. photon energy deposition, is mainly responsible for temperature rise in non-fuelled zones of nuclear reactors, including JHR internal structures and irradiation devices. As temperature is a key parameter for physical models describing the behavior of material, accurate control of temperature, and hence gamma heating, is required in irradiation devices and samples in order to perform an advanced suitable analysis of future experimental results. From a broader point of view, JHR global attractiveness as a MTR depends on its ability to monitor experimental parameters with high accuracy, including gamma heating. Strict control of temperature levels is also necessary in terms of safety. As JHR structures are warmed up by gamma heating, they must be appropriately cooled down to prevent creep deformation or melting. Cooling-power sizing is based on calculated levels of gamma heating in the JHR. Due to these safety concerns, accurate calculation of gamma heating with well-controlled bias and associated uncertainty as low as possible is all the more important. There are two main kinds of calculation bias: bias coming from nuclear data on the one hand and bias coming from physical approximations assumed by computer codes and by general calculation route on the other hand. The former must be determined by comparison between calculation and experimental data; the latter by calculation comparisons between codes and between methodologies. In this presentation, we focus on this latter kind of bias. Nuclear

  18. Final report on CCQM-K80: Comparison of value-assigned CRMs and PT materials: Creatinine in human serum

    Science.gov (United States)

    Camara, Johanna E.; Duewer, David L.; Gasca Aragon, Hugo; Lippa, Katrice A.; Toman, Blaza

    2013-01-01

    The 2009 CCQM-K80 'Comparison of value-assigned CRMs and PT materials: creatinine in human serum' is the first in a series of key comparisons directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes. CCQM-K80 compared the assigned serum creatinine values of certified reference materials (CRMs) using measurements made on these materials under repeatability conditions. Six NMIs submitted 17 CRM materials for evaluation, all intended for sale to customers. These materials represent nearly all of the higher-order CRMs then available for this clinically important measurand. The certified creatinine mass fraction in the materials ranged from 3 mg/kg to 57 mg/kg. All materials were stored and prepared according the specifications provided by each NMI. Samples were processed and analyzed under repeatability conditions by one analyst using isotope dilution liquid chromatography-mass spectrometry. The instrumental repeatability imprecision, expressed as a percent relative standard deviation, was 1.2%. Given the number of materials and the time required for each analysis, the measurements were made in two measurement campaigns ('runs'). In both campaigns, replicate analyses (two injections of one preparation separated in time) were made on each of two or three independently prepared aliquots from one randomly selected unit of each of the 17 materials. The mean value, between-campaign, between-aliquot and between-replicate variance components, standard uncertainty of the mean value, and the number of degrees of freedom associated with the standard uncertainty were estimated using a linear mixed model. Since several of the uncertainties estimated using this traditional frequentist approach were associated with a single degree of freedom, Markov Chain Monte Carlo Bayesian analysis was used to estimate 95% level-of-confidence coverage intervals, U95. Uncertainty-weighted generalized distance

  19. Characterization of Sodium Spray Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C. T.; Koontz, R. L.; Silberberg, M. [Atomics International, North American Rockwell Corporation, Canoga Park, CA (United States)

    1968-12-15

    The consequences of pool and spray fires require evaluation in the safety analysis of liquid metal-cooled fast breeder reactors. Sodium spray fires are characterized by high temperature and pressure, produced during the rapid combustion of sodium in air. Following the initial energy release, some fraction of the reaction products are available as aerosols which follow the normal laws of agglomeration, growth, settling, and plating. An experimental study is underway at Atomics International to study the characteristics of high concentration sprays of liquid sodium in reduced oxygen atmospheres and in air. The experiments are conducted in a 31.5 ft{sup 3} (2 ft diam. by 10 ft high) vessel, certified for a pressure of 100 lb/in{sup 2} (gauge). The spray injection apparatus consists of a heated sodium supply pot and a spray nozzle through which liquid sodium is driven by nitrogen pressure. Spray rate and droplet size can be varied by the injection velocity (nozzle size, nitrogen pressure, and sodium temperature). Aerosols produced in 0, 4, and 10 vol. % oxygen environments have been studied. The concentration and particle size distribution of the material remaining in the air after the spray injection and reaction period are measured. Fallout rates are found to be proportional to the concentration of aerosol which remains airborne following the spray period. (author)

  20. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk

    2017-01-01

    Since the Industrial Revolution, the anthropogenic emission of greenhouse gases has been increasing, leading to a rise in the global temperature. Particularly in the Arctic, climate change is having serious impact where the average temperature has increased almost twice as much as the global during......, ammonium, black carbon, and trace metals. This PhD dissertation studies Arctic aerosols and their sources, with special focus on black carbon, attempting to increase the knowledge about aerosols’ effect on the climate in an Arctic content. The first part of the dissertation examines the diversity...... of aerosol emissions from an important anthropogenic aerosol source: residential wood combustion. The second part, characterizes the chemical and physical composition of aerosols while investigating sources of aerosols in the Arctic. The main instrument used in this research has been the state...

  1. Aerosol in the containment

    International Nuclear Information System (INIS)

    Lanza, S.; Mariotti, P.

    1986-01-01

    The US program LACE (LWR Aerosol Containment Experiments), in which Italy participates together with several European countries, Canada and Japan, aims at evaluating by means of a large scale experimental activity at HEDL the retention in the pipings and primary container of the radioactive aerosol released following severe accidents in light water reactors. At the same time these experiences will make available data through which the codes used to analyse the behaviour of the aerosol in the containment and to verify whether by means of the codes of thermohydraulic computation it is possible to evaluate with sufficient accuracy variable influencing the aerosol behaviour, can be validated. This report shows and compares the results obtained by the participants in the LACE program with the aerosol containment codes NAVA 5 and CONTAIN for the pre-test computations of the test LA 1, in which an accident called containment by pass is simulated

  2. Where and What Is Pristine Marine Aerosol?

    Science.gov (United States)

    Russell, L. M.; Frossard, A. A.; Long, M. S.; Burrows, S. M.; Elliott, S.; Bates, T. S.; Quinn, P.

    2014-12-01

    The sources and composition of atmospheric marine aerosol particles have been measured by functional group composition (from Fourier transform infrared spectroscopy) to identify the organic composition of the pristine primary marine (ocean-derived) particles as 65% hydroxyl, 21% alkane, 6% amine, and 7% carboxylic acid functional groups [Frossard et al., 2014a,b]. Pristine but non-primary components from photochemical reactions (likely from biogenic marine vapor emissions) add carboxylic acid groups. Non-pristine contributions include shipping effluent in seawater and ship emissions, which add additional alkane groups (up to 70%), and coastal or continental emissions mix in alkane and carboxylic acid groups. The pristine primary marine (ocean-derived) organic aerosol composition is nearly identical to model generated primary marine aerosol particles from bubbled seawater, indicating that its overall functional group composition is the direct consequence of the organic constituents of the seawater source. While the seawater organic functional group composition was nearly invariant across all three ocean regions studied and the ratio of organic carbon to sodium (OC/Na+) in the generated primary marine aerosol particles remained nearly constant over a broad range of chlorophyll-a concentrations, the generated primary marine aerosol particle alkane group fraction increased with chlorophyll-a concentrations. In addition, the generated primary marine aerosol particles have a hydroxyl group absorption peak location characteristic of monosaccharides and disaccharides, where the seawater hydroxyl group peak location is closer to that of polysaccharides. References Cited Frossard, Amanda A., Lynn M. Russell, Paola Massoli, Timothy S. Bates, and Patricia K. Quinn, "Side-by-Side Comparison of Four Techniques Explains the Apparent Differences in the Organic Composition of Generated and Ambient Marine Aerosol Particles," Aerosol Science and Technology - Aerosol Research Letter

  3. Airborne Lidar Measurements of Aerosol Optical Properties During SAFARI-2000

    Science.gov (United States)

    McGill, M. J.; Hlavka, D. L.; Hart, W. D.; Welton, E. J.; Campbell, J. R.; Starr, David OC. (Technical Monitor)

    2002-01-01

    The Cloud Physics Lidar (CPL) operated onboard the NASA ER-2 high altitude aircraft during the SAFARI-2000 field campaign. The CPL provided high spatial resolution measurements of aerosol optical properties at both 1064 nm and 532 nm. We present here results of planetary boundary layer (PBL) aerosol optical depth analysis and profiles of aerosol extinction. Variation of optical depth and extinction are examined as a function of regional location. The wide-scale aerosol mapping obtained by the CPL is a unique data set that will aid in future studies of aerosol transport. Comparisons between the airborne CPL and ground-based MicroPulse Lidar Network (MPL-Net) sites are shown to have good agreement.

  4. Comparison of the MARC and CRAC2 programs for assessing the radiological consequences of accidental releases of radioactive material

    CERN Document Server

    Hemming, C R; Charles, D; Ostmeyer, R M

    1983-01-01

    This report describes a comparison of the MARC (Methodology for Assessing Radiological Consequences) and CRAC2 (Calculation of Reactor Accident Consequences, version 2) computer programs for assessing the radiological consequences of accidental releases of radioactive material. A qualitative comparison has been made of the features of the constituent sub-models of the two codes, and potentially the most important differences identified. The influence of these differences has been investigated quantitatively by comparison of the predictions of the two codes in a wide variety of circumstances. Both intermediate quantities and endpoints used as a measure of risk have been compared in order to separate the variables more clearly. The results indicate that, in general, the predictions of MARC and CRAC2 are in good agreement.

  5. Final report on CCQM-K79: Comparison of value-assigned CRMs and PT materials: Ethanol in aqueous matrix

    Science.gov (United States)

    Hein, Sebastian; Philipp, Rosemarie; Duewer, David L.; Gasca Aragon, Hugo; Lippa, Katrice A.; Toman, Blaza

    2013-01-01

    The 2010 CCQM-K79 'Comparison of value-assigned CRMs and PT materials: Ethanol in aqueous media' is the second key comparison directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes (DIs). CCQM-K79 compared the assigned ethanol values of proficiency test (PT) and certified reference materials (CRMs) using measurements made on these materials under repeatability conditions. Nine NMIs submitted 27 CRM or value-assigned PT materials for evaluation. These materials represent many of the higher-order reference materials then available for this commercially and forensically important measurand. The assigned ethanol mass fraction in the materials ranged from 0.1 mg/kg to 334 mg/kg. All materials were stored and prepared according the specifications provided by each NMI. Samples were processed and analyzed under repeatability conditions by one analytical team using a gas chromatography with flame ionization detection (GC-FID) method of demonstrated trueness and precision. Given the number of materials and the time required for each analysis, the majority of the measurements were made in two measurement campaigns ('runs'). Due to a shipping delay from one NMI, an unanticipated third campaign was required. In all three campaigns, replicate analyses (three injections of one preparation separated in time) were made for one randomly selected unit of each of the 27 materials. Nine of the 27 materials were gravimetrically diluted before measurement to provide solutions with ethanol mass fraction in the established linear range of the GC-FID method. The repeatability measurement value for each analyzed solution was estimated as the mean of all replicate values. The within- and between-campaign variance components were estimated using one-way ANOVA. Markov Chain Monte Carlo Bayesian analysis was used to estimate 95% level-of-confidence coverage intervals for the mean values. Uncertainty

  6. Comprehensive Measurement of Atmospheric Aerosols with a Wide Range Aerosol Spectrometer

    International Nuclear Information System (INIS)

    Keck, L; Pesch, M; Grimm, H

    2011-01-01

    A wide range aerosol spectrometer (WRAS) was used for comprehensive long term measurements of aerosol size distributions. The system combines the results of an optical aerosol spectrometer with the results of a Scanning Mobility Particle Sizer (SMPS) to record essentially the full size range (5 nm - 32 μm) of atmospheric particles in 72 channels. Measurements were carried out over one year (2009) at the Global Atmospheric Watch (GAW)-Station Hohenpeissenberg, Bavaria. Total particle number concentrations obtained from the aerosol size distributions were compared to the total number concentrations measured by a Condensation Particle Counter (CPC). The comparison showed an excellent agreement of the data. The high time resolution of 5 minutes allows the combination of the measured size distributions with meteorological data and correlations to gaseous pollutants (CO, NOx and SO2). A good correlation of particle number and CO concentrations was found for long distance transported small particles, which were probably mainly soot particles. Correlations to NOx were observed for aerosols from local sources such as traffic emissions. The formation of secondary aerosols from gaseous precursors was also observed. Episodes of relatively high concentration of particles in the range of 2-3 μm were probably caused by pollen.

  7. Comparison of the Contact stress and friction behavior of SiC and ZrO2 materials

    International Nuclear Information System (INIS)

    Lindberg, L.J.; Richerson, D.W.

    1985-01-01

    Studies were performed to further elucidate the friction and contact- stress characteristics of structural ceramic materials. New data for fully stabilized and partially stabilized zirconia ceramics are compared with prior test results for sintered SiC. The comparison provides further evidence that the high temperature friction characteristics of sinstered SiC are strongly influenced by the presence of a viscous surface layer. The results also show that a ceramic material with lower coefficient of friction and higher fracture toughness has increased resistance to strength-reducing surface damage due to contact stress

  8. Long term atmospheric aerosol characterization in the Amazon Basin

    Science.gov (United States)

    Artaxo, Paulo; Gerab, Fábio; Yamasoe, Marcia A.

    This chapter presents a characterization of atmospheric aerosols collected in different places in the Amazon Basin. Both the biogenic aerosol emission from the forest and the particulate material which is emitted to the atmosphere due to the large scale man-made burns during the dry season were studied. The samples were collected during a three year period at three different locations in the Amazon (Cuiabá, Alta Floresta and Serra do Navio), using stacked filter units. Aerosol samples were also collected directly over fires of cerrado vegetation and tropical primary forest burns The samples were analyzed using several techniques for a number of elements. Gravimetric analyses were used to determine the total atmospheric aerosol concentration. Multivariate statistical analysis was used in order to identify and characterize the sources of the atmospheric aerosol present in the sampled regions. Cerrado burning emissions were enriched compared to forest ones, specially for Cl, K and Zn. High atmospheric aerosol concentrations were observed in large amazonian areas due to emissions from man-made burns in the period from June to September. The emissions from burns dominate the fine fraction of the atmospheric aerosol with characteristic high contents of black carbon, S and K. Aerosols emitted in biomass burning process are correlated to the increase in the aerosol optical thickness of the atmosphere during the Amazonian dry season. The Serra do Navio aerosol is characterized by biogenic emissions with strong marine influence. The presence of trace elements characteristic of soil particulate associated with this marine contribution indicates the existence of aerosol transport from Africa to South America. Similar composition characteristics were observed in the biogenic emission aerosols from Serra do Navio and Alta Floresta.

  9. DARE : Dedicated Aerosols Retrieval Experiment

    NARCIS (Netherlands)

    Smorenburg, K.; Courrèges-Lacoste, G.B.; Decae, R.; Court, A.J.; Leeuw, G. de; Visser, H.

    2004-01-01

    At present there is an increasing interest in remote sensing of aerosols from space because of the large impact of aerosols on climate, earth observation and health. TNO has performed a study aimed at improving aerosol characterisation using a space based instrument and state-of-the-art aerosol

  10. Development, validation and comparison of two stability-indicating RP-LC methods using charged aerosol and UV detectors for analysis of lisdexamfetamine dimesylate in capsules

    Directory of Open Access Journals (Sweden)

    Graciela Carlos

    2016-11-01

    Full Text Available Two new stability-indicating liquid chromatographic methods using two detectors, an ultraviolet (UV and a charged aerosol detector (CAD simultaneously connected in series were validated for the assessment of lisdexamfetamine dimesylate (LDX in capsule. The method was optimized and the influence of individual parameters on UV and CAD response and sensitivity was studied. Chromatography was performed on a Zorbax CN column (250 mm × 4.6 mm, 5 μm in an isocratic elution mode, using acetonitrile and 20 mM ammonium formate at pH 4.0 (50:50, v/v as mobile phase and UV detection at 207 nm. The developed method was validated according to ICH guidelines and the parameters’ specificity, limit of detection, limit of quantitation, linearity, accuracy, precision and robustness were evaluated. CAD is designated to be a non-linear detector in a wide dynamic range, however, the method was linear over the concentration range of 70–130 μg mL−1 in both detectors. The method was precise and accurate. Robustness study was performed by a Plackett–Burman design, delivering results within the acceptable range. Neither the excipients nor the degradation products showed interference in the method after studies of specificity as well as under stress conditions. The results of the LC-UV and LC-CAD methods were statistically compared through ANOVA and showed no significant difference (p > 0.05. Both proposed methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate quality control tool for routine analysis of LDX in capsule.

  11. Comparison of a Material Point Method and a Galerkin Meshfree Method for the Simulation of Cohesive-Frictional Materials

    Directory of Open Access Journals (Sweden)

    Ilaria Iaconeta

    2017-09-01

    Full Text Available The simulation of large deformation problems, involving complex history-dependent constitutive laws, is of paramount importance in several engineering fields. Particular attention has to be paid to the choice of a suitable numerical technique such that reliable results can be obtained. In this paper, a Material Point Method (MPM and a Galerkin Meshfree Method (GMM are presented and verified against classical benchmarks in solid mechanics. The aim is to demonstrate the good behavior of the methods in the simulation of cohesive-frictional materials, both in static and dynamic regimes and in problems dealing with large deformations. The vast majority of MPM techniques in the literatrue are based on some sort of explicit time integration. The techniques proposed in the current work, on the contrary, are based on implicit approaches, which can also be easily adapted to the simulation of static cases. The two methods are presented so as to highlight the similarities to rather than the differences from “standard” Updated Lagrangian (UL approaches commonly employed by the Finite Elements (FE community. Although both methods are able to give a good prediction, it is observed that, under very large deformation of the medium, GMM lacks robustness due to its meshfree natrue, which makes the definition of the meshless shape functions more difficult and expensive than in MPM. On the other hand, the mesh-based MPM is demonstrated to be more robust and reliable for extremely large deformation cases.

  12. Radiological/biological/aerosol removal system

    Science.gov (United States)

    Haslam, Jeffery J

    2015-03-17

    An air filter replacement system for existing buildings, vehicles, arenas, and other enclosed airspaces includes a replacement air filter for replacing a standard air filter. The replacement air filter has dimensions and air flow specifications that allow it to replace the standard air filter. The replacement air filter includes a filter material that removes radiological or biological or aerosol particles.

  13. Comparison of the surface roughness of gypsum models constructed using various impression materials and gypsum products

    Directory of Open Access Journals (Sweden)

    Yi-Chih Chang

    2016-03-01

    Conclusion: The surface roughness of stone models was mainly determined by the type of alginate impression material, and was less affected by the type of silicone rubber impression material or gypsum product, or the storage time before repouring.

  14. Aerosol climate time series from ESA Aerosol_cci (Invited)

    Science.gov (United States)

    Holzer-Popp, T.

    2013-12-01

    Within the ESA Climate Change Initiative (CCI) the Aerosol_cci project (mid 2010 - mid 2013, phase 2 proposed 2014-2016) has conducted intensive work to improve algorithms for the retrieval of aerosol information from European sensors AATSR (3 algorithms), PARASOL, MERIS (3 algorithms), synergetic AATSR/SCIAMACHY, OMI and GOMOS. Whereas OMI and GOMOS were used to derive absorbing aerosol index and stratospheric extinction profiles, respectively, Aerosol Optical Depth (AOD) and Angstrom coefficient were retrieved from the other sensors. Global datasets for 2008 were produced and validated versus independent ground-based data and other satellite data sets (MODIS, MISR). An additional 17-year dataset is currently generated using ATSR-2/AATSR data. During the three years of the project, intensive collaborative efforts were made to improve the retrieval algorithms focusing on the most critical modules. The team agreed on the use of a common definition for the aerosol optical properties. Cloud masking was evaluated, but a rigorous analysis with a pre-scribed cloud mask did not lead to improvement for all algorithms. Better results were obtained using a post-processing step in which sudden transitions, indicative of possible occurrence of cloud contamination, were removed. Surface parameterization, which is most critical for the nadir only algorithms (MERIS and synergetic AATSR / SCIAMACHY) was studied to a limited extent. The retrieval results for AOD, Ångström exponent (AE) and uncertainties were evaluated by comparison with data from AERONET (and a limited amount of MAN) sun photometer and with satellite data available from MODIS and MISR. Both level2 and level3 (gridded daily) datasets were validated. Several validation metrics were used (standard statistical quantities such as bias, rmse, Pearson correlation, linear regression, as well as scoring approaches to quantitatively evaluate the spatial and temporal correlations against AERONET), and in some cases

  15. Transport and characterization of ambient biological aerosol near Laurel, MD

    Science.gov (United States)

    Santarpia, J. L.; Cunningham, D.; Gilberry, J.; Kim, S.; Smith, E. E.; Ratnesar-Shumate, S.; Quizon, J.

    2010-09-01

    Bacterial aerosol have been observed and studied in the ambient environment since the mid nineteenth century. These studies have sought to provide a better understanding of the diversity, variability and factors that control the biological aerosol population. In this study, we show comparisons between diversity of culturable bacteria and fungi, using culture and clinical biochemical tests, and 16S rRNA diversity using Affymetrix PhyloChips. Comparing the culturable fraction and surveying the total 16S rRNA of each sample provides a comprehensive look at the bacterial population studied and allows comparison with previous studies. Thirty-six hour back-trajectories of the air parcels sampled, over the two day period beginning 4 November 2008, provide information on the sources of aerosol sampled on the campus of Johns Hopkins University Applied Physics Laboratory in Laurel, MD. This study indicates that back-trajectory modeling of air parcels may provide insights into the observed diversity of biological aerosol.

  16. Bronchial and pulmonary scintigraphy with radioactively marked aerosols

    International Nuclear Information System (INIS)

    Wuerstle, T.

    1982-01-01

    In 97 patients with bronchitis, bronchial asthma, tuberculosis, sarcoidosis, pneumoconiosis, or tumors the mucociliary clearance and/or deposit pattern after inhalation of radioactively marked aerosols (1 mCi 99m Tc sulfur colloid) was studied. Normal values of the mucociliary 30 min. clearance for the central bronchial/lung periphery are 21%/15%. There was a decreased clearance with bronchitis (11/8%), bronchial asthma, emphysema, tuberculosis, sarcoidosis, trachiobronchial amyloidosis, pleural scarring or interstitial pneumona. Increased clearance (29/19%) was shown with pneumoconiosis. The correlation of deposit pattern and disease, for example, bronchitis, bronchial asthma, bullous emphysema, pleural scarring, partial lung resection, bronchopneumonia, or bronchial restriction, is described. In comparison of aerosol scintigraphy to perfusion scintigraphy and ventilation with gaseous xenon, the aerosol scintigraphy is superior to xenon for certain indications. The aerosol particles, which are larger in comparison to xenon, settle easier by obstructions or flow variations and thereby give better clinical indications of regional differences. (orig.) [de

  17. Culture through Comparison: Creating Audio-Visual Listening Materials for a CLIL Course

    Science.gov (United States)

    Zhyrun, Iryna

    2016-01-01

    Authentic listening has become a part of CLIL materials, but it can be difficult to find listening materials that perfectly match the language level, length requirements, content, and cultural context of a course. The difficulty of finding appropriate materials online, financial limitations posed by copyright fees, and necessity to produce…

  18. Diffusivity measurements of volatile organics in levitated viscous aerosol particles

    Directory of Open Access Journals (Sweden)

    S. Bastelberger

    2017-07-01

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

  19. The role of semi-volatile organic compounds in the mesoscale evolution of biomass burning aerosol: a modeling case study of the 2010 mega-fire event in Russia

    Directory of Open Access Journals (Sweden)

    I. B. Konovalov

    2015-12-01

    Full Text Available Chemistry transport models (CTMs are an indispensable tool for studying and predicting atmospheric and climate effects associated with carbonaceous aerosol from open biomass burning (BB; this type of aerosol is known to contribute significantly to both global radiative forcing and to episodes of air pollution in regions affected by wildfires. Improving model performance requires systematic comparison of simulation results with measurements of BB aerosol and elucidation of possible reasons for discrepancies between them, which, by default, are frequently attributed in the literature to uncertainties in emission data. Based on published laboratory data on the atmospheric evolution of BB aerosol and using the volatility basis set (VBS framework for organic aerosol modeling, we examined the importance of taking gas-particle partitioning and oxidation of semi-volatile organic compounds (SVOCs into account in simulations of the mesoscale evolution of smoke plumes from intense wildfires that occurred in western Russia in 2010. Biomass burning emissions of primary aerosol components were constrained with PM10 and CO data from the air pollution monitoring network in the Moscow region. The results of the simulations performed with the CHIMERE CTM were evaluated by considering, in particular, the ratio of smoke-related enhancements in PM10 and CO concentrations (ΔPM10 and ΔCO measured in Finland (in the city of Kuopio, nearly 1000 km downstream of the fire emission sources. It is found that while the simulations based on a "conventional" approach to BB aerosol modeling (disregarding oxidation of SVOCs and assuming organic aerosol material to be non-volatile strongly underestimated values of ΔPM10/ΔCO observed in Kuopio (by a factor of 2, employing the "advanced" representation of atmospheric processing of organic aerosol material resulted in bringing the simulations to a much closer agreement with the ground measurements. Furthermore, taking gas

  20. Water content of aged aerosol

    OpenAIRE

    G. J. Engelhart; L. Hildebrandt; E. Kostenidou; N. Mihalopoulos; N. M. Donahue; S. N. Pandis

    2010-01-01

    The composition and physical properties of aged atmospheric aerosol were characterized at a remote sampling site on the northern coast of Crete, Greece during the Finokalia Aerosol Measurement Experiment in May 2008 (FAME-2008). A reduced Dry-Ambient Aerosol Size Spectrometer (DAASS) was deployed to measure the aerosol water content and volumetric growth factor of fine particulate matter. The particles remained wet even at relative humidity (RH) as low as 20%. The aerosol was acidic during mo...

  1. Activation of human leukocytes on tantalum trabecular metal in comparison to commonly used orthopedic metal implant materials.

    Science.gov (United States)

    Schildhauer, T A; Peter, E; Muhr, G; Köller, M

    2009-02-01

    We analyzed leukocyte functions and cytokine response of human leukocytes toward porous tantalum foam biomaterial (Trabecular Metaltrade mark, TM) in comparison to equally sized solid orthopedic metal implant materials (pure titanium, titanium alloy, stainless steel, pure tantalum, and tantalum coated stainless steel). Isolated peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophil leukocytes (PMN) were cocultured with equally sized metallic test discs for 24 h. Supernatants were analyzed for cytokine content by enzyme-linked immunosorbent assay. Compared to the other used test materials there was a significant increase in the release of IL (interleukin)-1ra and IL-8 from PMN, and of IL-1ra, IL-6, and TNF-alpha from PBMC in response to the TM material. The cytokine release correlated with surface roughness of the materials. In contrast, the release of IL-2 was not induced showing that mainly myeloid leukocytes were activated. In addition, supernatants of these leukocyte/material interaction (conditioned media, CM) were subjected to whole blood cell function assays (phagocytosis, chemotaxis, bacterial killing). There was a significant increase in the phagocytotic capacity of leukocytes in the presence of TM-conditioned media. The chemotactic response of leukocytes toward TM-conditioned media was significantly higher compared to CM obtained from other test materials. Furthermore, the bactericidal capacity of whole blood was enhanced in the presence of TM-conditioned media. These results indicate that leukocyte activation at the surface of TM material induces a microenvironment, which may enhance local host defense mechanisms.

  2. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  3. Preferential aerosolization of bacteria in bioaerosols generated in vitro.

    Science.gov (United States)

    Perrott, P; Turgeon, N; Gauthier-Levesque, L; Duchaine, C

    2017-09-01

    Little is known about how bacteria are aerosolized in terms of whether some bacteria will be found in the air more readily than others that are present in the source. This report describes in vitro experiments to compare aerosolization rates (also known as preferential aerosolization) of Gram-positive and Gram-negative bacteria as well as rod- and coccus-shaped bacteria, using two nebulization conditions. A consortium of five bacterial species was aerosolized in a homemade chamber. Aerosols generated with a commercial nebulizer and a homemade bubble-burst aerosol generator were compared. Data suggest that Pseudomonas aeruginosa was preferentially aerosolized in comparison to Moraxella catarrhalis, Lactobacillus paracasei, Staphylococcus aureus and Streptococcus suis, independently of the method of aerosolization. Bacterial integrity of Strep. suis was more preserved compared to other bacteria studied as revealed with PMA-qPCR. We reported the design of an aerosol chamber and bubble-burst generator for the in vitro study of preferential aerosolization. In our setting, preferential aerosolization was influenced by bacterial properties instead of aerosolization mechanism. These findings could have important implications for predicting the composition of bioaerosols in various locations such as wastewater treatment plants, agricultural settings and health care settings. © 2017 The Society for Applied Microbiology.

  4. The physical economy of the European Union. Cross-country comparison and determinants of material consumption

    International Nuclear Information System (INIS)

    Weisz, Helga; Krausmann, Fridolin; Amann, Christof; Eisenmenger, Nina; Erb, Karl-Heinz; Fischer-Kowalski, Marina; Hubacek, Klaus

    2006-01-01

    In this paper we investigate what determines observed differences in economy-wide material use among the EU-15 member states. The empirical basis for our analysis is an extended and revised material flow data set for each of the EU-15 countries in time series from 1970 to 2001. This data set comprises consistent data for domestic extraction, imports and exports as well as for derived material flow indicators, broken down by 12 types of materials. We compare the level and composition of domestic material consumption (DMC) in the EU-15 member states and identify determinants of the observed differences. Across the European Union member states overall DMC per capita varies by a factor of three ranging between 12 tonnes per capita in Italy and the United Kingdom and 37 tonnes per capita in Finland. This variability of DMC in the EU-15 is in a similar order of magnitude as the variability of GDP per capita or total primary energy supply per capita. Linear correlation analysis reveals that national income and final energy consumption relate to material use but cannot fully account for the observed differences in material consumption. By breaking down overall material flow indicators into 12 categories of materials and analysing their use patterns in detail, we identified a number of factors, socio-economic and natural, that influence the level and composition of economy-wide material use. Many of these factors are specific for certain types of materials, others are more general, and quite some driving factors counteract each other regarding the direction of their influence. Concluding we summarize the most important driving factors for domestic material consumption stressing population density as largely neglected but important explanatory variable for material use patterns, discuss issues of environmental significance, aggregation and the use of different denominators in material flow accounting and suggest a re-interpretation of DMC. (author)

  5. Comparison of physical and chemical properties of ambient aerosols during the 2009 haze and non-haze periods in Southeast Asia.

    Science.gov (United States)

    Xu, Jingsha; Tai, Xuhong; Betha, Raghu; He, Jun; Balasubramanian, Rajasekhar

    2015-10-01

    Recurrent smoke-haze episodes that occur in Southeast Asia (SEA) are of much concern because of their environmental and health impacts. These haze episodes are mainly caused by uncontrolled biomass and peat burning in Indonesia. Airborne particulate matter (PM) samples were collected in the southwest coast of Singapore from 16 August to 9 November in 2009 to assess the impact of smoke-haze episodes on the air quality due to the long-range transport of biomass and peat burning emissions. The physical and chemical characteristics of PM were investigated during pre-haze, smoke-haze, and post-haze periods. Days with PM2.5 mass concentrations of ≥35 μg m(-3) were considered as smoke-haze events. Using this criterion, out of the total 82 sampling days, nine smoke-haze events were identified. The origin of air masses during smoke-haze episodes was studied on the basis of HYSPLIT backward air trajectory analysis for 4 days. In terms of the physical properties of PM, higher particle surface area concentrations and particle gravimetric mass concentrations were observed during the smoke-haze period, but there was no consistent pattern for particle number concentrations during the haze period as compared to the non-haze period except that there was a significant increase at about 08:00, which could be attributed to the entrainment of PM from aloft after the breakdown of the nocturnal inversion layer. As for the chemical characteristics of PM, among the six key inorganic water-soluble ions (Cl(-), NO3(-), nss-SO4(2-), Na(+), NH4(+), and nss-K(+)) measured in this study, NO3(-), nss-SO4(2-), and NH4(+) showed a significant increase in their concentrations during the smoke-haze period together with nss-K(+). These observations suggest that the increased atmospheric loading of PM with higher surface area and increased concentrations of optically active secondary inorganic aerosols [(NH4)2SO4 or NH4HSO4 and NH4NO3] resulted in the atmospheric visibility reduction in SEA due to

  6. Quantitative estimates of the volatility of ambient organic aerosol

    Directory of Open Access Journals (Sweden)

    C. D. Cappa

    2010-06-01

    high and variable ΔHvap assumptions. Our results also show that the amount of semivolatile gas-phase organics in equilibrium with the OA could range from ~20% to 400% of the OA mass, with smaller values generally corresponding to the higher ΔHvap assumptions. The volatility of various OA components determined from factor analysis of AMS spectra has also been assessed. In general, it is found that the fraction of non-volatile material follows the pattern: biomass burning OA < hydrocarbon-like OA < semivolatile oxygenated OA < low-volatility oxygenated OA. Correspondingly, the sensitivity to dilution and the estimated amount of semivolatile gas-phase material for the OA factors follows the reverse order. Primary OA has a substantial semivolatile fraction, in agreement with previous results, while the non-volatile fraction appears to be dominated by oxygenated OA produced by atmospheric aging. The overall OA volatility is thus controlled by the relative contribution of each aerosol type to the total OA burden. Finally, the model/measurement comparison appears to require OA having an evaporation coefficient (γe substantially greater than 10−2; at this point it is not possible to place firmer constraints on γe based on the observations.

  7. Quantitative estimates of the volatility of ambient organic aerosol

    Science.gov (United States)

    Cappa, C. D.; Jimenez, J. L.

    2010-06-01

    % to 400% of the OA mass, with smaller values generally corresponding to the higher ΔHvap assumptions. The volatility of various OA components determined from factor analysis of AMS spectra has also been assessed. In general, it is found that the fraction of non-volatile material follows the pattern: biomass burning OA hydrocarbon-like OA < semivolatile oxygenated OA < low-volatility oxygenated OA. Correspondingly, the sensitivity to dilution and the estimated amount of semivolatile gas-phase material for the OA factors follows the reverse order. Primary OA has a substantial semivolatile fraction, in agreement with previous results, while the non-volatile fraction appears to be dominated by oxygenated OA produced by atmospheric aging. The overall OA volatility is thus controlled by the relative contribution of each aerosol type to the total OA burden. Finally, the model/measurement comparison appears to require OA having an evaporation coefficient (γe) substantially greater than 10-2; at this point it is not possible to place firmer constraints on γe based on the observations.

  8. Aerosol-Induced Radiative Flux Changes Off the United States Mid-Atlantic Coast: Comparison of Values Calculated from Sunphotometer and In Situ Data with Those Measured by Airborne Pyranometer

    Science.gov (United States)

    Russell, P. B.; Livingston, J. M.; Hignett, P.; Kinne, S.; Wong, J.; Chien, A.; Bergstrom, R.; Durkee, P.; Hobbs, P. V.

    2000-01-01

    The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) measured a variety of aerosol radiative effects (including flux changes) while simultaneously measuring the chemical, physical, and optical properties of the responsible aerosol particles. Here we use TARFOX-determined aerosol and surface properties to compute shortwave radiative flux changes for a variety of aerosol situations, with midvisible optical depths ranging from 0.06 to 0.55. We calculate flux changes by several techniques with varying degrees of sophistication, in part to investigate the sensitivity of results to computational approach. We then compare computed flux changes to those determined from aircraft measurements. Calculations using several approaches yield downward and upward flux changes that agree with measurements. The agreement demonstrates closure (i.e. consistency) among the TARFOX-derived aerosol properties, modeling techniques, and radiative flux measurements. Agreement between calculated and measured downward flux changes is best when the aerosols are modeled as moderately absorbing (midvisible single-scattering albedos between about 0.89 and 0.93), in accord with independent measurements of the TARPOX aerosol. The calculated values for instantaneous daytime upwelling flux changes are in the range +14 to +48 W/sq m for midvisible optical depths between 0.2 and 0.55. These values are about 30 to 100 times the global-average direct forcing expected for the global-average sulfate aerosol optical depth of 0.04. The reasons for the larger flux changes in TARFOX include the relatively large optical depths and the focus on cloud-free, daytime conditions over the dark ocean surface. These are the conditions that produce major aerosol radiative forcing events and contribute to any global-average climate effect.

  9. Comparison of lithium and the eutectic lead lithium alloy, two candidate liquid metal breeder materials for self-cooled blankets

    International Nuclear Information System (INIS)

    Malang, S.; Mattas, R.

    1994-06-01

    Liquid metals are attractive candidates for both near-term and long-term fusion applications. The subjects of this comparison are the differences between the two candidate liquid metal breeder materials Li and LiPb for use in breeding blankets in the areas of neutronics, magnetohydrodynamics, tritium control, compatibility with structural materials, heat extraction system, safety, and required R ampersand D program. Both candidates appear to be promising for use in self-cooled breeding blankets which have inherent simplicity with the liquid metal serving as both breeders and coolant. The remaining feasibility question for both breeder materials is the electrical insulation between liquid metal and duct walls. Different ceramic coatings are required for the two breeders, and their crucial issues, namely self-healing of insulator cracks and radiation induced electrical degradation are not yet demonstrated. Each liquid metal breeder has advantages and concerns associated with it, and further development is needed to resolve these concerns

  10. The hygroscopicity of indoor aerosol particles

    International Nuclear Information System (INIS)

    Wei, L.

    1993-07-01

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

  11. Comparison of the fractional power motor with cores made of various magnetic materials

    Directory of Open Access Journals (Sweden)

    Gmyrek Zbigniew

    2017-12-01

    Full Text Available The optimization of the motor cores, coupled with new core shapes as well as powering the motor at high frequency are the primary reasons for the use of new materials. The utilization of new materials, like SMC (soft magnetic composite, reduce the core loss and/or provide quasi-isotropic core’s properties in any magnetization direction. Moreover, the use of SMC materials allows for avoiding degradation of the material portions, resulting from punching process, thereby preventing the deterioration of operating parameters of the motor. The authors examine the impact of technological parameters on the properties of a new type of SMC material and analyze the possibility of its use as the core of the fractional power motor. The result of the work is an indication of the shape of the rotor core made of a new SMC material to achieve operational parameters similar to those that have a motor with a core made of laminations.

  12. Comparison of the fractional power motor with cores made of various magnetic materials

    Science.gov (United States)

    Gmyrek, Zbigniew; Lefik, Marcin; Cavagnino, Andrea; Ferraris, Luca

    2017-12-01

    The optimization of the motor cores, coupled with new core shapes as well as powering the motor at high frequency are the primary reasons for the use of new materials. The utilization of new materials, like SMC (soft magnetic composite), reduce the core loss and/or provide quasi-isotropic core's properties in any magnetization direction. Moreover, the use of SMC materials allows for avoiding degradation of the material portions, resulting from punching process, thereby preventing the deterioration of operating parameters of the motor. The authors examine the impact of technological parameters on the properties of a new type of SMC material and analyze the possibility of its use as the core of the fractional power motor. The result of the work is an indication of the shape of the rotor core made of a new SMC material to achieve operational parameters similar to those that have a motor with a core made of laminations.

  13. Sodium oxide aerosol filtration

    Energy Technology Data Exchange (ETDEWEB)

    Duverger de Cuy, G [DSN/SESTR, Centre de Cadarache, Saint-Paul-lez-Durance (France)

    1979-03-01

    In the scope of the sodium aerosol trapping research effort by the CEA/DSN, the retention capacity and yield were measured for very high efficiency fiberglass filters and several types of prefilters (cyclone agglomerator, fabric prefilters, water scrubbers). (author)

  14. Sodium aerosol recovering device

    International Nuclear Information System (INIS)

    Fujimori, Koji; Ueda, Mitsuo; Tanaka, Kazuhisa.

    1997-01-01

    A main body of a recovering device is disposed in a sodium cooled reactor or a sodium cooled test device. Air containing sodium aerosol is sucked into the main body of the recovering device by a recycling fan and introduced to a multi-staged metal mesh filter portion. The air about against each of the metal mesh filters, and the sodium aerosol in the air is collected. The air having a reduced sodium aerosol concentration circulates passing through a recycling fan and pipelines to form a circulation air streams. Sodium aerosol deposited on each of the metal mesh filters is scraped off periodically by a scraper driving device to prevent clogging of each of the metal filters. (I.N.)

  15. Aerosol chemical physics

    International Nuclear Information System (INIS)

    Marlow, W.H.

    1982-01-01

    A classification of the research fields in the chemical physics of aerosol microparticles is given. The emphasis lies on the microphysics of isolated particles and clusters and on physical transformations and thermodynamics. (LDN)

  16. Sodium oxide aerosol filtration

    International Nuclear Information System (INIS)

    Duverger de Cuy, G.

    1979-01-01

    In the scope of the sodium aerosol trapping research effort by the CEA/DSN, the retention capacity and yield were measured for very high efficiency fiberglass filters and several types of prefilters (cyclone agglomerator, fabric prefilters, water scrubbers). (author)

  17. Aerosols and Climate

    Indian Academy of Sciences (India)

    aerosols, clouds, radiation and climate. ... the solar radiation to pass through but absorb most of infrared radiation emitted .... Fine soil and sand particles become airborne due to wind. Over ..... its sampling is difficult compared to other species.

  18. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  19. Measurement of phase function of aerosol at different altitudes by CCD Lidar

    Science.gov (United States)

    Sun, Peiyu; Yuan, Ke'e.; Yang, Jie; Hu, Shunxing

    2018-02-01

    The aerosols near the ground are closely related to human health and climate change, the study on which has important significance. As we all know, the aerosol is inhomogeneous at different altitudes, of which the phase function is also different. In order to simplify the retrieval algorithm, it is usually assumed that the aerosol is uniform at different altitudes, which will bring measurement error. In this work, an experimental approach is demonstrated to measure the scattering phase function of atmospheric aerosol particles at different heights by CCD lidar system, which could solve the problem of the traditional CCD lidar system in assumption of phase function. The phase functions obtained by the new experimental approach are used to retrieve the aerosol extinction coefficient profiles. By comparison of the aerosol extinction coefficient retrieved by Mie-scattering aerosol lidar and CCD lidar at night, the reliability of new experimental approach is verified.

  20. Determination of material parameters by comparison of 3D simulations and 3D experiments

    DEFF Research Database (Denmark)

    Zhang, Jin

    microstructure and the measured microstructure in a global manner. The proposed method is demonstrated on a simple case to fit two material parameters: the liquid diffusion coefficient and the capillary length of a hypoeutectic Al-Cu alloy, and a complicated case to fit hundreds of material parameters......: the reduced grain boundary mobilities of pure iron. Results show that the proposed method is capable of providing reliable measurements of material parameters that are difficult to measure in traditional ways and can determine many - possibly all relevant - values of material parameters simultaneously...

  1. MISR Aerosol Typing

    Science.gov (United States)

    Kahn, Ralph A.

    2014-01-01

    AeroCom is an open international initiative of scientists interested in the advancement of the understanding of global aerosol properties and aerosol impacts on climate. A central goal is to more strongly tie and constrain modeling efforts to observational data. A major element for exchanges between data and modeling groups are annual meetings. The meeting was held September 20 through October 2, 1014 and the organizers would like to post the presentations.

  2. Supplementary Material for: BEACON: automated tool for Bacterial GEnome Annotation ComparisON

    KAUST Repository

    Kalkatawi, Manal M.; Alam, Intikhab; Bajic, Vladimir B.

    2015-01-01

    Abstract Background Genome annotation is one way of summarizing the existing knowledge about genomic characteristics of an organism. There has been an increased interest during the last several decades in computer-based structural and functional genome annotation. Many methods for this purpose have been developed for eukaryotes and prokaryotes. Our study focuses on comparison of functional annotations of prokaryotic genomes. To the best of our knowledge there is no fully automated system for detailed comparison of functional genome annotations generated by different annotation methods (AMs). Results The presence of many AMs and development of new ones introduce needs to: a/ compare different annotations for a single genome, and b/ generate annotation by combining individual ones. To address these issues we developed an Automated Tool for Bacterial GEnome Annotation ComparisON (BEACON) that benefits both AM developers and annotation analysers. BEACON provides detailed comparison of gene function annotations of prokaryotic genomes obtained by different AMs and generates extended annotations through combination of individual ones. For the illustration of BEACONâ s utility, we provide a comparison analysis of multiple different annotations generated for four genomes and show on these examples that the extended annotation can increase the number of genes annotated by putative functions up to 27 %, while the number of genes without any function assignment is reduced. Conclusions We developed BEACON, a fast tool for an automated and a systematic comparison of different annotations of single genomes. The extended annotation assigns putative functions to many genes with unknown functions. BEACON is available under GNU General Public License version 3.0 and is accessible at: http://www.cbrc.kaust.edu.sa/BEACON/ .

  3. Aerosol Delivery for Amendment Distribution in Contaminated Vadose Zones

    Science.gov (United States)

    Hall, R. J.; Murdoch, L.; Riha, B.; Looney, B.

    2011-12-01

    Remediation of contaminated vadose zones is often hindered by an inability to effectively distribute amendments. Many amendment-based approaches have been successful in saturated formations, however, have not been widely pursued when treating contaminated unsaturated materials due to amendment distribution limitations. Aerosol delivery is a promising new approach for distributing amendments in contaminated vadose zones. Amendments are aerosolized and injected through well screens. During injection the aerosol particles are transported with the gas and deposited on the surfaces of soil grains. Resulting distributions are radially and vertically broad, which could not be achieved by injecting pure liquid-phase solutions. The objectives of this work were A) to characterize transport and deposition behaviors of aerosols; and B) to develop capabilities for predicting results of aerosol injection scenarios. Aerosol transport and deposition processes were investigated by conducting lab-scale injection experiments. These experiments involved injection of aerosols through a 2m radius, sand-filled wedge. A particle analyzer was used to measure aerosol particle distributions with time, and sand samples were taken for amendment content analysis. Predictive capabilities were obtained by constructing a numerical model capable of simulating aerosol transport and deposition in porous media. Results from tests involving vegetable oil aerosol injection show that liquid contents appropriate for remedial applications could be readily achieved throughout the sand-filled wedge. Lab-scale tests conducted with aqueous aerosols show that liquid accumulation only occurs near the point of injection. Tests were also conducted using 200 g/L salt water as the aerosolized liquid. Liquid accumulations observed during salt water tests were minimal and similar to aqueous aerosol results. However, particles were measured, and salt deposited distal to the point of injection. Differences between

  4. Modeling Secondary Organic Aerosol Formation From Emissions of Combustion Sources

    Science.gov (United States)

    Jathar, Shantanu Hemant

    Atmospheric aerosols exert a large influence on the Earth's climate and cause adverse public health effects, reduced visibility and material degradation. Secondary organic aerosol (SOA), defined as the aerosol mass arising from the oxidation products of gas-phase organic species, accounts for a significant fraction of the submicron atmospheric aerosol mass. Yet, there are large uncertainties surrounding the sources, atmospheric evolution and properties of SOA. This thesis combines laboratory experiments, extensive data analysis and global modeling to investigate the contribution of semi-volatile and intermediate volatility organic compounds (SVOC and IVOC) from combustion sources to SOA formation. The goals are to quantify the contribution of these emissions to ambient PM and to evaluate and improve models to simulate its formation. To create a database for model development and evaluation, a series of smog chamber experiments were conducted on evaporated fuel, which served as surrogates for real-world combustion emissions. Diesel formed the most SOA followed by conventional jet fuel / jet fuel derived from natural gas, gasoline and jet fuel derived from coal. The variability in SOA formation from actual combustion emissions can be partially explained by the composition of the fuel. Several models were developed and tested along with existing models using SOA data from smog chamber experiments conducted using evaporated fuel (this work, gasoline, fischertropschs, jet fuel, diesels) and published data on dilute combustion emissions (aircraft, on- and off-road gasoline, on- and off-road diesel, wood burning, biomass burning). For all of the SOA data, existing models under-predicted SOA formation if SVOC/IVOC were not included. For the evaporated fuel experiments, when SVOC/IVOC were included predictions using the existing SOA model were brought to within a factor of two of measurements with minor adjustments to model parameterizations. Further, a volatility

  5. Design of automatic control and measurement software for radioactive aerosol continuity monitor

    International Nuclear Information System (INIS)

    Mao Yong; Li Aiwu

    1997-01-01

    The radioactive aerosol continuity measurement is very important for the development of nuclear industry, and it is the major method to measure and find out the leakage of radioactive material. Radioactive aerosol continuity monitor is the advanced method for the radioactive aerosol continuity measurement. With the development of nuclear industry and nuclear power station, it is necessary to design and automatic continuity measurement device. Because of this reason, the authors developed the first unit of radioactive aerosol continuity monitor and adopted the ministry appraisal. The design idea and method of automatic control and measurement for radioactive aerosol continuity monitor are discussed

  6. Comparison of the dynamic behaviour of brain tissue and two model materials

    NARCIS (Netherlands)

    Brands, D.W.A.; Bovendeerd, P.H.M.; Peters, G.W.M.; Wismans, J.S.H.M.; Paas, M.H.J.W.; Bree, van J.L.M.J.; Brands, D.W.A.

    1999-01-01

    Linear viscoelastic material parameters of porcine brain tissue and two brain substitute/ materials for use in mechanical head models (edible bone gelatin and dielectric silicone gel) were determined in small deformation, oscillatory shear experiments. Frequencies to 1000 Hertz could be obtained

  7. Comparison of the deflated preconditioned conjugate gradient method and algebraic multigrid for composite materials

    NARCIS (Netherlands)

    Jönsthövel, T.B.; Van Gijzen, M.B.; MacLachlan, S.; Vuik, C.; Scarpas, A.

    2012-01-01

    Many applications in computational science and engineering concern composite materials, which are characterized by large discontinuities in the material properties. Such applications require fine-scale finite-element meshes, which lead to large linear systems that are challenging to solve with

  8. Comparison of the deflated preconditioned conjugate gradient method and parallel direct solver for composite materials

    NARCIS (Netherlands)

    Jönsthövel, T.B.; Van Gijzen, M.B.; MacLachlan, S.; Vuik, C.; Scarpas, A.

    2011-01-01

    The demand for large FE meshes increases as parallel computing becomes the standard in FE simulations. Direct and iterative solution methods are used to solve the resulting linear systems. Many applications concern composite materials, which are characterized by large discontinuities in the material

  9. Radiodensity evaluation of dental impression materials in comparison to tooth structures

    Directory of Open Access Journals (Sweden)

    Rodrigo Borges Fonseca

    2010-10-01

    Full Text Available In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals. OBJECTIVE: The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin. MATERIAL AND METHODS: Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15, being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05. RESULTS: Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05, but not to bovine enamel (p<0.05. Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05. CONCLUSION: Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.

  10. Comparison between different regulations for transport of radioactive materials; Comparaison de differents reglements de transports des substances radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Pallier, Lucien

    1961-11-20

    This comparison is based on the study of several regulations and conventions: French regulations for transports (by rail, road, river, sea, air, and mail), international regulations applicable in France for transports (by rail, road, air, sea, and mail), the general regulation for transport of the International Atomic Energy Agency, and the convention on civil responsibility of the European Agency for Nuclear Energy. The author notices that IAEA regulation will probably prevail. He outlines the objectives and the necessity of regulations, identifies the risk factors (nature of radio-elements, physical condition of the material, type of packaging), discusses additional safety measures, outlines that risks must not be overestimated, and the importance of labelling, and then discusses the comparison of the different considered regulations. He addresses the determination of the risk associated with a transport, the issue of responsibility. The content of regulations is presented in several tables.

  11. Analysis of plant gums and saccharide materials in paint samples: comparison of GC-MS analytical procedures and databases.

    Science.gov (United States)

    Lluveras-Tenorio, Anna; Mazurek, Joy; Restivo, Annalaura; Colombini, Maria Perla; Bonaduce, Ilaria

    2012-10-10

    Saccharide materials have been used for centuries as binding media, to paint, write and illuminate manuscripts and to apply metallic leaf decorations. Although the technical literature often reports on the use of plant gums as binders, actually several other saccharide materials can be encountered in paint samples, not only as major binders, but also as additives. In the literature, there are a variety of analytical procedures that utilize GC-MS to characterize saccharide materials in paint samples, however the chromatographic profiles are often extremely different and it is impossible to compare them and reliably identify the paint binder. This paper presents a comparison between two different analytical procedures based on GC-MS for the analysis of saccharide materials in works-of-art. The research presented here evaluates the influence of the analytical procedure used, and how it impacts the sugar profiles obtained from the analysis of paint samples that contain saccharide materials. The procedures have been developed, optimised and systematically used to characterise plant gums at the Getty Conservation Institute in Los Angeles, USA (GCI) and the Department of Chemistry and Industrial Chemistry of the University of Pisa, Italy (DCCI). The main steps of the analytical procedures and their optimisation are discussed. The results presented highlight that the two methods give comparable sugar profiles, whether the samples analysed are simple raw materials, pigmented and unpigmented paint replicas, or paint samples collected from hundreds of centuries old polychrome art objects. A common database of sugar profiles of reference materials commonly found in paint samples was thus compiled. The database presents data also from those materials that only contain a minor saccharide fraction. This database highlights how many sources of saccharides can be found in a paint sample, representing an important step forward in the problem of identifying polysaccharide binders in

  12. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available . It is generally included as part of a structurally insulated panel (SIP) where the foam is sandwiched between external skins of steel, wood or cement. Cement composites Cement bonded composites are an important class of building materials. These products... for their stone buildings, including the Egyptians, Aztecs and Inca’s. As stone is a very dense material it requires intensive heating to become warm. Rocks were generally stacked dry but mud, and later cement, can be used as a mortar to hold the rocks...

  13. Isotopic Tracers to Identify Far-traveled Pollutant and Mineral Aerosols in Northern California (Invited)

    Science.gov (United States)

    Depaolo, D. J.; Christensen, J. N.; Ewing, S. A.; Cliff, S. S.; Brown, S. T.; Vancuren, R. A.

    2009-12-01

    Mineral dust and pollutant aerosols can be lofted into the atmosphere and transported 1000s of kilometers, facilitating intercontinental communication of soil components, biological material (bacteria, viruses) and anthropogenic particulates. Far-traveled aerosols also affect air quality, atmospheric radiation balance and cloud formation. Understanding the sources of aerosols, and how they evolve with climate change, land use changes, and emerging industrial activity, is important for assessing air quality and climate processes in California. A particular concern for California is trans-Pacific transport of mineral aerosols from Asian deserts, and the possibility that industrial and other pollutants accompany them. The geographic sources of mineral and pollutant aerosols can in many cases be determined from their isotopic composition, using for example some combination of elements such as Pb, Sr, Nd, Hf, Zn, N, S, C, O, U, B, and Li. With systematic sample collection and analysis, isotopes can provide quantification of the changing proportions of local versus distant sources. Where the far-traveled components can be identified, comparisons can be made to meteorological data to better understand the factors controlling the efficiency of long-range transport. With heavy dust storms, such as those that arise in the Sahel/Sahara or the deserts of Asia, aerosols can be tracked in satellite imagery and other approaches may not be necessary. During more common periods of lesser aerosol loading, and where greater transport distances are involved, ground-based methods such as chemical analysis of a time-series of collected PM2.5 are needed to evaluate sources. Pollutants may or may not accompany mineral dust, and may be added along the transport path. Although chemical analysis is useful, relatively fast and inexpensive, more information, and in some cases more definitive conclusions, can be obtained by adding isotopic measurements. By combining multiple isotopic systems (e

  14. Comparison of common lignin methods and modifications on forage and lignocellulosic biomass materials.

    Science.gov (United States)

    Goff, Ben M; Murphy, Patrick T; Moore, Kenneth J

    2012-03-15

    A variety of methods have been developed for estimating lignin concentration within plant materials. The objective of this study was to compare the lignin concentrations produced by six methods on a diverse population of forage and biomass materials and to examine the relationship between these concentrations and the portions of these materials that are available for utilisation by livestock or for ethanol conversion. Several methods produced lignin concentrations that were highly correlated with the digestibility of the forages, but there were few relationships between these methods and the available carbohydrate of the biomass materials. The use of Na₂SO₃ during preparation of residues for hydrolysis resulted in reduced lignin concentrations and decreased correlation with digestibility of forage materials, particularly the warm-season grasses. There were several methods that were well suited for predicting the digestible portion of forage materials, with the acid detergent lignin and Klason lignin method giving the highest correlation across the three types of forage. The continued use of Na₂SO₃ during preparation of Van Soest fibres needs to be evaluated owing to its ability to reduce lignin concentrations and effectiveness in predicting the utilisation of feedstuffs and feedstocks. Because there was little correlation between the lignin concentration and the biomass materials, there is a need to examine alternative or develop new methods to estimate lignin concentrations that may be used to predict the availability of carbohydrates for ethanol conversion. Copyright © 2011 Society of Chemical Industry.

  15. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  16. Radiodensity evaluation of dental impression materials in comparison to tooth structures.

    Science.gov (United States)

    Fonseca, Rodrigo Borges; Branco, Carolina Assaf; Haiter-Neto, Francisco; Gonçalves, Luciano de Souza; Soares, Carlos José; Carlo, Hugo Lemes; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

    2010-01-01

    In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals. The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin. Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15), being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05). Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05), but not to bovine enamel (p<0.05). Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05). Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.

  17. Assessment of the threat from diverted radioactive material and 'orphan sources' - An international comparison

    International Nuclear Information System (INIS)

    Steinhausler, F.

    2001-01-01

    Full text: Multiple international activities have been undertaken to contain the trafficking of weapons-usable material in order to reduce the risk from the proliferation of such material. In addition, over the past decade the issue of unintended handling and transport of radioactive material has become increasingly important. Concurrent with the growing number of radioactive sources in industry, medicine, agriculture and research, the probability for losing control over such sources increases as well ('orphan sources'). The potential impact on society and the environment from these two categories of threat has been documented extensively in the literature. In this study representatives from 11 countries in the Americas, Europe and Asia-Pacific formed a network to exchange information concerning nuclear and other radioactive material on the following topic areas: Legislation and regulatory practices for the production, processing, handling, use, holding, storage, transport, import, and export; History of site-specific non-compliance and enforcement actions, as well as punitive actions; National approach for handling the issue of orphan sources; The role of national security forces; Managerial and technical procedures to ensure material inventory control and accountancy; Aspects of physical protection on-site and during transport; Technical/scientific expertise and equipment available at the national level to detect, identify and quantify such material in the field; Level of practical implementation of technical equipment to detect such material at border crossings, airports, railway stations, and mail distribution centres; Cases of seizure of nuclear and contaminated materials, illegal sales and fraud; Training programmes available for preventing, detecting and responding to the loss of control. The results of the analysis show that, despite several international consensus documents and supporting legislation, in several cases major additional efforts are needed

  18. Comparison of solute-binding properties of plastic materials used as pharmaceutical product containers.

    Science.gov (United States)

    Jenke, Dennis; Couch, Tom; Gillum, Amy

    2010-01-01

    Material/water equilibrium binding constants (E(b)) were determined for 11 organic solutes and 2 plastic materials commonly used in pharmaceutical product containers (plasticized polyvinyl chloride and polyolefin). In general, solute binding by the plasticized polyvinyl chloride material was greater, by nearly an order of magnitude, than the binding by the polyolefin (on an equal weight basis). The utilization of the binding constants to facilitate container compatibility assessments (e.g., drug loss by container binding) for drug-containing products is discussed.

  19. Comparison of material property specifications of ferritic steels in fast-breeder reactor technology

    International Nuclear Information System (INIS)

    Delporte, E.; Vanderborck, Y.

    1988-01-01

    The component fabrications for the fast breeder reactors request the use of ferritic steels specially appropriated for the construction of the equipments sustaining pressure and high temperature. The Activity Group nr 3 Materials of the FRCC has decided to make a study to compare the different norms related to the properties of somme ferritic steels used in the different European fast breeder projects. In particular, this study should allow in the different countries of the Community, to identify the designation of a specific steel and to compare its properties. Deviations between the different norms of a same material are mentioned to facilitate European standardization of this type of material

  20. Sensitive detection of aerosol effect on simulated IASI spectral radiance

    International Nuclear Information System (INIS)

    Quan, X.; Huang, H.-L.; Zhang, L.; Weisz, E.; Cao, X.

    2013-01-01

    Guided by radiative transfer modeling of the effects of dust (aerosol) on satellite thermal infrared radiance by many different imaging radiometers, in this article, we present the aerosol-effected satellite radiative signal changes in the top of atmosphere (TOA). The simulation of TOA radiance for Infrared Atmospheric Sounding Interferometer (IASI) is performed by using the RTTOV fast radiative transfer model. The model computation is carried out with setting representative geographical atmospheric models and typical default aerosol climatological models under clear sky condition. The radiative differences (in units of equivalent black body brightness temperature differences (BTDs)) between simulated radiances without consideration of the impact of aerosol (Aerosol-free) and with various aerosol models (Aerosol-modified) are calculated for the whole IASI spectrum between 3.62 and 15.5 μm. The comparisons of BTDs are performed through 11 aerosol models in 5 classified atmospheric models. The results show that the Desert aerosol model has the most significant impact on IASI spectral simulated radiances than the other aerosol models (Continental, Urban, Maritime types and so on) in Mid-latitude Summer, contributing to the mineral aerosol components contained. The value of BTDs could reach up to 1 K at peak points. The atmospheric window spectral region between 900 and 1100 cm −1 (9.09–11.11 μm) is concentrated after the investigation for the largest values of aerosol-affected radiance differences. BTDs in IASI spectral region between 645 and 1200 cm −1 occupies the largest oscillation and the major part of the whole spectrum. The IASI highest window peak-points channels (such as 9.4 and 10.2 μm) are obtained finally, which are the most sensitive ones to the simulated IASI radiance. -- Highlights: ► Sensitive study of aerosol effect on simulated IASI spectral radiance is performed. ► The aerosol components have influenced IASI spectral regions

  1. Dry Friction Clutch Disc of an Automobile under Transient Thermal Load: A Comparison of Friction Lining Materials

    Directory of Open Access Journals (Sweden)

    Ali Anosh

    2017-01-01

    Full Text Available This paper shows the comparison of temperatures produced in a dry friction clutch disc with different materials during a single engagement to assist in clutch plate design and analysis. A study of usage of different materials for friction lining of clutch disc is required, which will provide improved performance and enhanced life. This investigation is modelled mathematically and solved numerically using finite element method. ANSYS® 15.0 is a dedicated finite element package used for determining the temperature distribution across a clutch disc. In the present work, an investigation of a conventionally used harmful friction lining material asbestos is compared with carbon-carbon composite, S2-glass fibre and aluminium metal matrix composite. The transient thermal analysis of a clutch disc with different materials is performed and the temperature distribution on the clutch system is compared. Simulation results indicate that all the values of the temperature obtained from the analysis of aluminium metal matrix are less than those of asbestos based lining material, therefore clutch disc made up of aluminium metal matrix composite will assure the extended service life and the longer stability due to the fact that the temperature responsible for the wear and tear has been reduced. Furthermore, the slipping time is also considered in this investigation.

  2. Comparison of salt solution and air drying methods for moisture fixation in highly porous building materials

    DEFF Research Database (Denmark)

    Antonov, Yovko Ivanov; Jensen, Rasmus Lund; Møldrup, Per

    2017-01-01

    In recent years, research has identified some bio-based, porous building materials as good or excellent regulators of moisture in buildings. The ability of a material to absorb, release and store moisture is described by vapour sorption isotherms. It is necessary input to simulations of indoor...... building materials by a standardized testing method, using saturated salt solutions. Furthermore, results from the standard method are compared to values of moisture content for the same materials, obtained by air-drying at different relative humidity. This is done with the aim to compare the findings from...... the two methods with respect to time and repeatability of the results. Derived isotherms are further used as direct input in the building simulation software BSim, which is capable of predicting indoor environment parameters by solving coupled, transient heat and moisture transport equations using finite...

  3. A Deep Morphological Characterization and Comparison of Different Dental Restorative Materials

    Directory of Open Access Journals (Sweden)

    R. Condò

    2017-01-01

    Full Text Available Giomer is a relatively new class of restorative material with aesthetics, handling and physical properties of composite resins, and benefits of glass ionomers: high radiopacity, antiplaque effect, fluoride release, and recharge. To verify the superior properties of Giomers, in this study, a deep morphological characterization has been performed with an in vitro comparative study among a Giomer (Beautifil® II by Shofu Dental Corporation, Osaka, Japan, a Compomer (Dyract Extra by Dentsply, Caulk, Germany, glass ionomer cement (Ketac fil plus by 3M ESPE, and a composite resin (Tetric Evoceram by Ivoclar. In particular, mechanical and optical properties and ageing effects have been compared to investigate materials similarities and differences. Indentation tests, UV-Visible spectroscopy, Raman spectroscopy, and weight loss after storage in saliva or sugary drink have been carried out to analyze materials behavior in real conditions. The results confirm the high quality of Giomer material and indicate possible improvements in their usage.

  4. A comparison of sawdust and wood shavings as litter materials for ...

    African Journals Online (AJOL)

    -Amponsem, A Osei-Somuah. Abstract. The suitability of sawdust as litter material for broilers was assessed by comparing broiler performance on it with performance on wood shavings in a 49-day trial. Criteria for assessment included body ...

  5. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis.

    KAUST Repository

    Siegert, Michael; Yates, Matthew D; Call, Douglas F; Zhu, Xiuping; Spormann, Alfred; Logan, Bruce E

    2014-01-01

    In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials

  6. Comparison of Properties of Polymer Composite Materials Reinforced with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Zygoń P.

    2015-04-01

    Full Text Available Carbon nanotubes because of their high mechanical, optical or electrical properties, have found use as semiconducting materials constituting the reinforcing phase in composite materials. The paper presents the results of the studies on the mechanical properties of polymer composites reinforced with carbon nanotubes (CNT. Three-point bending tests were carried out on the composites. The density of each obtained composite was determined as well as the surface roughness and the resistivity at room temperature.

  7. Material properties of Grade 91 steel at elevated temperature and their comparison with a design code

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeong Yeon; Kim, Woo Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Han Sang; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of)

    2013-10-15

    In this study, the material properties of tensile strength, creep properties, and creep crack growth model for Gr.91 steel at elevated temperature were obtained from material tests at KAERI, and the test data were compared with those of the French elevated temperature design code, RCC-MRx. The conservatism of the material properties in the French design code is highlighted. Mod.9Cr-1Mo (ASME Grade 91; Gr.91) steel is widely adopted as candidate material for Generation IV nuclear systems as well as for advanced thermal plants. In a Gen IV sodium-cooled fast reactor of the PGSFR (Prototype Gen IV Sodium-cooled Fast Reactor) being developed by KAERI (Korea Atomic Energy Research Institute), Gr.91 steel is selected as the material for the steam generator, secondary piping, and decay heat exchangers. However, as this material has a relatively shorter history of usage in an actual plant than austenitic stainless steel, there are still many issues to be addressed including the long-term creep rupture life extrapolation and ratcheting behavior with cyclic softening characteristics.

  8. The Creativity Dimension of Instructional Materials Designed by Prospective Teachers: The Comparison across Domains

    Directory of Open Access Journals (Sweden)

    Ersoy Esen

    2017-01-01

    Full Text Available This study aims at revealing the creativity dimension of the materials designed and developed by the second year students studying at the department of Computer Education and Instructional Technology. A part of the participants has completed the process by designing materials in their own field, information technologies; while some of them have done so by designing materials in the field of mathematics. The data have been retrieved from an experimental study of 13 weeks. “Teaching Material Creativity Rubric” developed by the researchers, has been used as the data collection tool. The rubric has been developed in order to evaluate the creativity dimensions of products. While developing the rubric, the creative product evaluation dimensions of [14] have been a source of inspiration. The products developed by the students have been evaluated through the retrieved data, in terms of their creativity. The rubric developed includes Originality, Practicality & Sensibility, Productivity & Flexibility, Feasibility, Inclusiveness, and Insightfulness dimensions. In this research, the data of the aforementioned dimensions and sub-dimensions have been evaluated. The results present that the creativity level of the products on teaching information technologies, which have been developed by Computer Education and Instructional Technology (CEIT students, is high. It has been argued that the creativity of domain-specifically developed materials is higher, through literature. Keywords: Material Design in Computers, Mathematics Teaching, Originality, Applicability, Creativity, Creativity and Domainswords.

  9. The impact of aerosol vertical distribution on aerosol optical depth retrieval using CALIPSO and MODIS data: Case study over dust and smoke regions

    Science.gov (United States)

    Wu, Yerong; de Graaf, Martin; Menenti, Massimo

    2017-08-01

    Global quantitative aerosol information has been derived from MODerate Resolution Imaging SpectroRadiometer (MODIS) observations for decades since early 2000 and widely used for air quality and climate change research. However, the operational MODIS Aerosol Optical Depth (AOD) products Collection 6 (C6) can still be biased, because of uncertainty in assumed aerosol optical properties and aerosol vertical distribution. This study investigates the impact of aerosol vertical distribution on the AOD retrieval. We developed a new algorithm by considering dynamic vertical profiles, which is an adaptation of MODIS C6 Dark Target (C6_DT) algorithm over land. The new algorithm makes use of the aerosol vertical profile extracted from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) measurements to generate an accurate top of the atmosphere (TOA) reflectance for the AOD retrieval, where the profile is assumed to be a single layer and represented as a Gaussian function with the mean height as single variable. To test the impact, a comparison was made between MODIS DT and Aerosol Robotic Network (AERONET) AOD, over dust and smoke regions. The results show that the aerosol vertical distribution has a strong impact on the AOD retrieval. The assumed aerosol layers close to the ground can negatively bias the retrievals in C6_DT. Regarding the evaluated smoke and dust layers, the new algorithm can improve the retrieval by reducing the negative biases by 3-5%.

  10. Physical metrology of aerosols; Metrologie physique des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Boulaud, D.; Vendel, J. [CEA Saclay, 91 - Gif-sur-Yvette (France). Inst. de Protection et de Surete Nucleaire

    1996-12-31

    The various detection and measuring methods for aerosols are presented, and their selection is related to aerosol characteristics (size range, concentration or mass range), thermo-hydraulic conditions (carrier fluid temperature, pressure and flow rate) and to the measuring system conditions (measuring frequency, data collection speed, cost...). Methods based on aerosol dynamic properties (inertial, diffusional and electrical methods) and aerosol optical properties (localized and integral methods) are described and their performances and applications are compared

  11. Large-scale experiments on aerosol behavior in light water reactor containments

    International Nuclear Information System (INIS)

    Schock, W.; Bunz, H.; Adams, R.E.; Tobias, M.L.; Rahn, F.J.

    1988-01-01

    Recently, three large-scale experimental programs were carried out dealing with the behavior of aerosols during core-melt accidents in light water reactors (LWRs). In the Nuclear Safety Pilot Plant (NSPP) program, the principal behaviors of different insoluble aerosols and of mixed aerosols were measured in dry air atmospheres and in condensing steam-air atmospheres contained in a 38-m/sup 3/ steel vessel. The Demonstration of Nuclear Aerosol Behavior (DEMONA) program used a 640-m/sup 3/ concrete containment model to simulate typical accident sequence conditions, and measured the behavior of different insoluble aerosols and mixed aerosols in condensing and transient atmospheric conditions. Part of the LWR Aerosol Containment Experiments (LACE) program was also devoted to aerosol behavior in containment; and 852-m/sup 3/ steel vessel was used, and the aerosols were composed of mixtures of insoluble and soluble species. The results of these experiments provide a suitable data base for validation of aerosol behavior codes. Fundamental insight into details of aerosol behavior in condensing environments has been gained through the results of the NSPP tests. Code comparisons have been and are being performed in the DEMONA and LACE experiments

  12. Aerosol Activation Properties within and above Mixing Layer in the North China Plain

    Science.gov (United States)

    Deng, Z.; Ran, L.

    2013-12-01

    Aerosol particles, serving as cloud condensation nuclei (CCN), may modify the properties of clouds and have an impact on climate. The vertical distribution of aerosols and their activation properties is critical to quantify the effect of aerosols on clouds. An intensive field campaign, Vertical Observations of trace Gases and Aerosols in the North China Plain (VOGA-NCP 2013), was conducted in the North China Plain during the late July and early August 2013 to measure the vertical profiles of atmospheric components in this polluted region and estimate their effects on atmospheric environment and climate. Aerosols were measured with in-situ instruments and Lidar. Particularly, the aerosols were collected at 1000 m height with a 1 m3 bag sampler attached to a tethered balloon, and subsequently measured with combined scanning mobility particle sizer (SMPS) and CCN counter. Comparisons of size-resolved activation ratios at ground level and 1000 m height showed that aerosols in upper atmosphere were not only less concentrated, but also less CCN-active than those at the surface. The difference in aerosol properties between upper atmosphere and the ground indicates that the analysis of impacts of aerosols on cloud might be misleading in heavily polluted region based on the relationship of cloud properties and surface aerosols or column without considering the vertical distribution of aerosol activation abilities.

  13. Characterization of aerosols produced by surgical procedures: A summary

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Hsu-Chi; Muggenburg, B.A.; Lundgren, D.L.; Turner, R.S.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K.

    1994-11-01

    In many types of surgery, especially orthopedic procedures, power tools such as saws and drills are used. These tools can impart considerable energy in disrupting tissue and may produce aerosolized blood and material from bone and other tissues. Surgical lasers and electrocautery tools can also produce aerosols due to vaporization of blood and tissues. A number of studies have been reported concerning production of aerosols during surgery, and some of the aerosols produced may contain infectious materials. Health care workers have expressed concern and questions pertaining to the occupational transmission of blood-borne pathogens including the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) via blood aerosols during surgery. Little or no data existed characterizing the aerosols produced performing surgical procedures. Because of this lack of data, the National Institute for Occupational Safety and Health funded a project at ITRI to assess the extent of aerosolization of blood and other tissues during surgical procedures in the laboratory and in a hospital surgical suite.

  14. Characterization of aerosols produced by surgical procedures: A summary

    International Nuclear Information System (INIS)

    Yeh, Hsu-Chi; Muggenburg, B.A.; Lundgren, D.L.; Turner, R.S.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K.

    1994-01-01

    In many types of surgery, especially orthopedic procedures, power tools such as saws and drills are used. These tools can impart considerable energy in disrupting tissue and may produce aerosolized blood and material from bone and other tissues. Surgical lasers and electrocautery tools can also produce aerosols due to vaporization of blood and tissues. A number of studies have been reported concerning production of aerosols during surgery, and some of the aerosols produced may contain infectious materials. Health care workers have expressed concern and questions pertaining to the occupational transmission of blood-borne pathogens including the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) via blood aerosols during surgery. Little or no data existed characterizing the aerosols produced performing surgical procedures. Because of this lack of data, the National Institute for Occupational Safety and Health funded a project at ITRI to assess the extent of aerosolization of blood and other tissues during surgical procedures in the laboratory and in a hospital surgical suite

  15. Characterisation of aerosols produced by laser cutting

    International Nuclear Information System (INIS)

    Fauvel, S.; Pilot, G.; Dinechin, G. de; Gosse, X.; Arnaud, P.

    2007-01-01

    Powerful lasers represent a promising alternative solution to traditional cutting processes used in dismantling nuclear equipments. The use of optical fibers has an unquestionable advantage when dealing with airtight workshops. A study funded by COGEMA Marcoule was undertaken by IRSN/SERAC in collaboration with GIP/GERAILP in order to characterise the aerosols emitted by the cutting of evaporators elements with a 4 kW continuous wave Nd:YAG laser. For this study, laser cutting has been carried out in a tight room of 35 m 3 connected to a particle sampling pipe. Iso-kinetic samplers allowed the measurement of the aerosol concentration. A diffusional and inertial spectrometer (SDI 2001) - an Andersen impinger coupled to a diffusion battery - provided the size distribution. An electrostatic filter used upstream a HEPA filter, itself placed before the extractor fan, collected the majority of the emitted aerosol. Its efficiency was measured and controlled throughout the experiments. The results show the influence of the cutting conditions on the characteristics of the aerosol, and allow a comparison with other cutting tools. (authors)

  16. Comparison of Piezo-material based Energy Transduction Systems for Artificial Nanoswimmer

    Science.gov (United States)

    Nain, S.; Rathore, J. S.; Sharma, N. N.

    2018-04-01

    The energy harnessing is a process of obtaining energy from the surrounding environment and converting into electrical energy. In the last two decades, there has been a plenteous study in energy harnessing. Now a day, energy harnessing using piezoelectric materials has drawn attention of researchers due to low cost, flexibility and light weight. The benefits of piezoelectric material can be utilized by designing a self-powered device for artificial nanoswimmer. Some of the ceramics which displays the piezoelectric effect are lead-zirconate-titanate (PZT), lead-titanate (PbTiO2), lead-zirconate (PbZrO3) and Barium Titanate (BaTiO3). PZT is most extensively used piezoelectric material in the field of energy harnessing but it is brittle in nature. Lead based piezoelectric materials are toxic in nature and may not suitable for in-vivo biomedical applications. To eradicate this problem, researchers are interested in synthesizing lead free piezoelectric material such as Aluminium Nitride (AIN), Barium Titanate (BaTiO3) and Polyvinylidenefluoride (PVDF). The biocompatibility of PVDF makes it appropriate to be used for energy harnessing in human body for applications like on board powering of nanoswimmer for various disease detection and drug delivery. In this paper, a cantilever beam is being simulated in COMSOL to study electric potential generated on the surface of beam made of different piezoelectric materials such as AIN, PVDF and PZT due to fluidic pressure, which will be utilized as energy for actuation of artificial nanoswimmer. Piezo-based cantilever beams have been compared and maximum electric potential is being observed in PVDF based beam. PVDF seems most promising piezoelectric material for in-vivo biomedical application and it is readily available.

  17. Measurements of non-volatile aerosols with a VTDMA and their correlations with carbonaceous aerosols in Guangzhou, China

    Science.gov (United States)

    Cheung, Heidi H. Y.; Tan, Haobo; Xu, Hanbing; Li, Fei; Wu, Cheng; Yu, Jian Z.; Chan, Chak K.

    2016-07-01

    Simultaneous measurements of aerosol volatility and carbonaceous matters were conducted at a suburban site in Guangzhou, China, in February and March 2014 using a volatility tandem differential mobility analyzer (VTDMA) and an organic carbon/elemental carbon (OC / EC) analyzer. Low volatility (LV) particles, with a volatility shrink factor (VSF) at 300 °C exceeding 0.9, contributed 5 % of number concentrations of the 40 nm particles and 11-15 % of the 80-300 nm particles. They were composed of non-volatile material externally mixed with volatile material, and therefore did not evaporate significantly at 300 °C. Non-volatile material mixed internally with the volatile material was referred to as medium volatility (MV, 0.4 transported at low altitudes (below 1500 m) for over 40 h before arrival. Further comparison with the diurnal variations in the mass fractions of EC and the non-volatile OC in PM2.5 suggests that the non-volatile residuals may be related to both EC and non-volatile OC in the afternoon, during which the concentration of aged organics increased. A closure analysis of the total mass of LV and MV residuals and the mass of EC or the sum of EC and non-volatile OC was conducted. It suggests that non-volatile OC, in addition to EC, was one of the components of the non-volatile residuals measured by the VTDMA in this study.

  18. The aerosols and the greenhouse effect; Aerosoler og klimaeffekten

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, Trond; Kirkevaag, Alf; Seland, Oeyvind; Debernard, Jens Boldingh; Kristjansson, Jon Egill; Storelvmo, Trude

    2008-07-01

    The article discussed the aerosol effects on the climatic changes and points out that the climate models do not incorporate these components satisfactorily mostly due to insufficient knowledge of the aerosol pollution sources. The direct and indirect effects of aerosols are mentioned as well as the climate response (tk)

  19. EPDM and fluorocarbon seal materials: a comparison of performance for nuclear fuel transport flasks

    International Nuclear Information System (INIS)

    Chivers, T.C.; George, A.F.

    2004-01-01

    The lid seals on the flasks used to transport spent fuel from U.K. AGR and Magnox Power Stations are fluorocarbon elastomer 'O' rings. Currently, only this material is qualified for the purpose and it was decided to investigate the possibility of qualifying other materials. One material that is already in use in similar applications is an Ethylene Propylene Diene Monomer (EPDM). The work presented in this paper compares the performance of the existing material with three candidate types of EPDM. The areas considered were: Extrusion and blow-out resistance when subjected to various steam pressures and temperatures at a range of flange separations, Permeability to water, caesium salt solution and hydrogen (as a typical 'benchmark' gas) Radiation resistance in warm (60 C) aqueous conditions It is concluded that the performance of the EPDM materials is good in respect of mechanical properties, radiation and water resistance. However, while permeation rates for gas and water can be higher than for fluorocarbon, this might be mitigated by assessing the actual radioactive burden in the permeate. In the case of dissolved salts, the test results indicate that this will be very low

  20. Quantification of Optical and Physical Properties of Combustion-Generated Carbonaceous Aerosols (

    Science.gov (United States)

    Perera, Inoka Eranda; Litton, Charles D

    2015-03-01

    A series of experiments were conducted to quantify and characterize the optical and physical properties of combustion-generated aerosols during both flaming and smoldering combustion of three materials common to underground mines-Pittsburgh Seam coal, Styrene Butadiene Rubber (a common mine conveyor belt material), and Douglas-fir wood-using a combination of analytical and gravimetric measurements. Laser photometers were utilized in the experiments for continuous measurement of aerosol mass concentrations and for comparison to measurements made using gravimetric filter samples. The aerosols of interest lie in the size range of tens to a few hundred nanometers, out of range of the standard photometer calibration. To correct for these uncertainties, the photometer mass concentrations were compared to gravimetric samples to determine if consistent correlations existed. The response of a calibrated and modified combination ionization/photoelectric smoke detector was also used. In addition, the responses of this sensor and a similar, prototype ionization/photoelectric sensor, along with discrete angular scattering, total scattering, and total extinction measurements, were used to define in real time the size, morphology, and radiative transfer properties of these differing aerosols that are generally in the form of fractal aggregates. SEM/TEM images were also obtained in order to compare qualitatively the real-time, continuous experimental measurements with the visual microscopic measurements. These data clearly show that significant differences exist between aerosols from flaming and from smoldering combustion and that these differences produce very different scattering and absorption signatures. The data also indicate that ionization/photoelectric sensors can be utilized to measure continuously and in real time aerosol properties over a broad spectrum of applications related to adverse environmental and health effects.

  1. TEM investigations of microstructures of combustion aerosols

    International Nuclear Information System (INIS)

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

    1992-12-01

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

  2. Aerosol-type retrieval and uncertainty quantification from OMI data

    Science.gov (United States)

    Kauppi, Anu; Kolmonen, Pekka; Laine, Marko; Tamminen, Johanna

    2017-11-01

    We discuss uncertainty quantification for aerosol-type selection in satellite-based atmospheric aerosol retrieval. The retrieval procedure uses precalculated aerosol microphysical models stored in look-up tables (LUTs) and top-of-atmosphere (TOA) spectral reflectance measurements to solve the aerosol characteristics. The forward model approximations cause systematic differences between the modelled and observed reflectance. Acknowledging this model discrepancy as a source of uncertainty allows us to produce more realistic uncertainty estimates and assists the selection of the most appropriate LUTs for each individual retrieval.This paper focuses on the aerosol microphysical model selection and characterisation of uncertainty in the retrieved aerosol type and aerosol optical depth (AOD). The concept of model evidence is used as a tool for model comparison. The method is based on Bayesian inference approach, in which all uncertainties are described as a posterior probability distribution. When there is no single best-matching aerosol microphysical model, we use a statistical technique based on Bayesian model averaging to combine AOD posterior probability densities of the best-fitting models to obtain an averaged AOD estimate. We also determine the shared evidence of the best-matching models of a certain main aerosol type in order to quantify how plausible it is that it represents the underlying atmospheric aerosol conditions.The developed method is applied to Ozone Monitoring Instrument (OMI) measurements using a multiwavelength approach for retrieving the aerosol type and AOD estimate with uncertainty quantification for cloud-free over-land pixels. Several larger pixel set areas were studied in order to investigate the robustness of the developed method. We evaluated the retrieved AOD by comparison with ground-based measurements at example sites. We found that the uncertainty of AOD expressed by posterior probability distribution reflects the difficulty in model

  3. Aerosol-type retrieval and uncertainty quantification from OMI data

    Directory of Open Access Journals (Sweden)

    A. Kauppi

    2017-11-01

    Full Text Available We discuss uncertainty quantification for aerosol-type selection in satellite-based atmospheric aerosol retrieval. The retrieval procedure uses precalculated aerosol microphysical models stored in look-up tables (LUTs and top-of-atmosphere (TOA spectral reflectance measurements to solve the aerosol characteristics. The forward model approximations cause systematic differences between the modelled and observed reflectance. Acknowledging this model discrepancy as a source of uncertainty allows us to produce more realistic uncertainty estimates and assists the selection of the most appropriate LUTs for each individual retrieval.This paper focuses on the aerosol microphysical model selection and characterisation of uncertainty in the retrieved aerosol type and aerosol optical depth (AOD. The concept of model evidence is used as a tool for model comparison. The method is based on Bayesian inference approach, in which all uncertainties are described as a posterior probability distribution. When there is no single best-matching aerosol microphysical model, we use a statistical technique based on Bayesian model averaging to combine AOD posterior probability densities of the best-fitting models to obtain an averaged AOD estimate. We also determine the shared evidence of the best-matching models of a certain main aerosol type in order to quantify how plausible it is that it represents the underlying atmospheric aerosol conditions.The developed method is applied to Ozone Monitoring Instrument (OMI measurements using a multiwavelength approach for retrieving the aerosol type and AOD estimate with uncertainty quantification for cloud-free over-land pixels. Several larger pixel set areas were studied in order to investigate the robustness of the developed method. We evaluated the retrieved AOD by comparison with ground-based measurements at example sites. We found that the uncertainty of AOD expressed by posterior probability distribution reflects the

  4. Comparison of filter media materials for heavy metal removal from urban stormwater runoff using biofiltration systems.

    Science.gov (United States)

    Lim, H S; Lim, W; Hu, J Y; Ziegler, A; Ong, S L

    2015-01-01

    The filter media in biofiltration systems play an important role in removing potentially harmful pollutants from urban stormwater runoff. This study compares the heavy metal removal potential (Cu, Zn, Cd, Pb) of five materials (potting soil, compost, coconut coir, sludge and a commercial mix) using laboratory columns. Total/dissolved organic carbon (TOC/DOC) was also analysed because some of the test materials had high carbon content which affects heavy metal uptake/release. Potting soil and the commercial mix offered the best metal uptake when dosed with low (Cu: 44.78 μg/L, Zn: 436.4 μg/L, Cd, 1.82 μg/L, Pb: 51.32 μg/L) and high concentrations of heavy metals (Cu: 241 μg/L, Zn: 1127 μg/L, Cd: 4.57 μg/L, Pb: 90.25 μg/L). Compost and sludge also had high removal efficiencies (>90%). Heavy metal leaching from these materials was negligible. A one-month dry period between dosing experiments did not affect metal removal efficiencies. TOC concentrations from all materials increased after the dry period. Heavy metal removal was not affected by filter media depth (600 mm vs. 300 mm). Heavy metals tended to accumulate at the upper 5 cm of the filter media although potting soil showed bottom-enriched concentrations. We recommend using potting soil as the principal media mixed with compost or sludge since these materials perform well and are readily available. The use of renewable materials commonly found in Singapore supports a sustainable approach to urban water management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. In vitro comparison of coronal microleakage of four temporary restorative materials used in endodontic treatment

    Directory of Open Access Journals (Sweden)

    Shahi Sh.

    2008-10-01

    Full Text Available "nBackground and Aim: The use of proper temporary restorative materials between appointments is critical in successful root canal treatment. The purpose of this study was to compare the coronal microleakage of four temporary restorative materials including Zonalin, Zamherir, Coltosol and IRM. "nMaterials and Methods: In this in vitro study, standard access cavities were prepared in 120 intact extracted maxillary and mandibular human first molars. Canal preparation was carried out by the step-back technique, and obturation was performed with gutta-percha and AH26 sealer using the lateral condensation technique. Teeth were randomly divided into 4 experimental groups of 25 teeth each and two positive and negative control groups, each containing 10 teeth. In each experimental group the access cavity was restored with one of the tested materials (Zamherir, Zonalin, IRM and Coltosol. In the negative control group the access cavity was filled entirely with sticky wax and in the positive control group no restorative material was applied. Dye penetration technique was used to evaluate microleakage which was measured under a stereomicroscope. Data were analyzed with one way ANOVA and post hoc Tukey tests. P<0.05 was considered as the limit of significance. "nResults: Dye penetration was observed in all groups. Zonalin and Coltosol had the highest and the lowest dye penetration respectively, with a statistically significant difference (p<0.001. There was no significant difference in dye penetration between IRM, and either Coltosol or Zamherir (p>0.05. "nConclusion: The results of this study showed that using Coltosol as a temporary restorative material can provide a better coronal seal in endodontic treatments

  6. Satellite remote sensing of Asian aerosols: a case study of clean, polluted, and Asian dust storm days

    Directory of Open Access Journals (Sweden)

    K. H. Lee

    2010-12-01

    Full Text Available In East Asia, satellite observation is important because aerosols from natural and anthropogenic sources have been recognized as a major source of regional and global air pollution. However, retrieving aerosols properties from satellite observations over land can be difficult because of the surface reflection, complex aerosol composition, and aerosol absorption. In this study, a new aerosol retrieval method called as the Moderate Resolution Imaging Spectroradiometer (MODIS satellite aerosol retrieval (MSTAR was developed and applied to three different aerosol event cases over East Asia. MSTAR uses a separation technique that can distinguish aerosol reflectance from top-of-atmosphere (TOA reflectance. The aerosol optical thickness (AOT was determined by comparing this aerosol reflectance with pre-calculated values. Three case studies show how the methodology identifies discrepancies between measured and calculated values to retrieve more accurate AOT. The comparison between MODIS and the Aerosol Robotic Network (AERONET showed improvement using the suggested methodology with the cluster-based look-up-tables (LUTs (linear slope = 0.94, R = 0.92 than using operational MODIS collection 5 aerosol products (linear slope = 0.78, R = 0.87. In conclusion, the suggested methodology is shown to work well with aerosol models acquired by statistical clustering of the observation data in East Asia.

  7. Comparison of radioactivity data measured in PM10 aerosol samples at two elevated stations in northern Italy during the Fukushima event.

    Science.gov (United States)

    Tositti, Laura; Brattich, Erika; Cinelli, Giorgia; Previti, Alberto; Mostacci, Domiziano

    2012-12-01

    The follow-up of Fukushima radioactive plume resulting from the 11th March 2011 devastating tsunami is discussed for two Italian stations in the northern Apennines: Mt. Cimone (Modena) and Montecuccolino (Bologna). Radioactivity data collected at both stations are described, including comparison between local natural background of airborne particulate and artificial radioactivity referable to the arrival of the radioactive plume and its persistence and evolution. Analysis of back-trajectories was used to confirm the arrival of artificial radionuclides following atmospheric transport and processing. The Fukushima plume was first detected on 3rd April 2011 when high volume sampling revealed the presence of the artificial radionuclides (131)I, (137)Cs and (134)Cs. The highest activity concentrations of these nuclides were detected on 5th April 2011 at the Montecuccolino site. Fukushima radioactivity data at the two stations were usually comparable, suggesting a good vertical mixing of the plume; discrepancies were occasional and attributed to different occurrence of wet removal, typically characterized by a scattered spatial pattern. To understand the relevance to the local population of the extra dose due to the Fukushima plume, atmospheric activities of the related artificial nuclides were compared to those of the main natural radionuclides in ambient particulate, and found to be lower by over one order of magnitude. Radiation doses referable to Fukushima, maximized for a whole year occurrence at the highest activity level observed at our stations in the weeks affected by the Japanese plume, were estimated at 1.1 μSv/year. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Comparison of a direct-reading device to gravimetric methods for evaluating organic dust aerosols in an enclosed swine production environment.

    Science.gov (United States)

    Taylor, C D; Reynolds, S J

    2001-01-01

    The production of livestock in enclosed facilities has become an accepted practice, driven by the need for increased efficiency. Exposure to organic dusts, containing various bioactive components, has been identified an important risk factor for the high rate of lung disease found among workers in these environments. Assessment of organic dust exposure requires technical skills and instrumentation not readily available to most agricultural enterprises. Development of a simple, cost-effective method for measuring organic dust levels would be useful in evaluating and controlling exposures in these environments. The objective of this study was to evaluate the usefulness of the direct reading MIE PDM-3 Miniram for estimating organic dust concentrations in enclosed swine production facilities. Responses from the MIE PDM-3 Miniram were compared to gravimetric methods for total and inhalable dust. Total dust determinations were conducted in accordance with the National Institute for Occupational Safety and Health (NIOSH) method 0500. Inhalable particulate mass (IPM) sampling was conducted using SKC brand IOM (Institute of Occupational Medicine) sampling cassettes, which meet the American Conference of Governmental Industrial Hygienists ACGIH criteria for inhalable dust sampling. This study design also allowed for the comparison of traditional total dust method to the IPM method, in collecting organic dusts in an agricultural setting. Fifteen sets of side-by-side samples (Miniram, total dust, and IPM) were collected over a period of six months in a swine confinement building. There were statistically significant differences in the results provided by the three sampling methods. Measurements for inhalable dust exceeded those for total dust in eleven of fifteen samples. The Miniram time-weighted average (TWA) response to the organic dust was always the lower of the three methods. A high degree of correlation was found among all three methods. The Miniram performed well under

  9. Comparison of detector materials for time-of-flight positron tomography

    International Nuclear Information System (INIS)

    Derenzo, S.E.

    1982-06-01

    Knowledge of detection efficiency and timing resolution is essential when comparing detector materials for time-of-flight positron tomography. We present results of Monte Carlo calculations of the detection efficiency of plastic, lead loaded plastic, NaI(T1), liquid xenon, bismuth germanate (BGO), CsF, BaF 2 , Ge, and HgI 2 for 511 keV photons. We also use recently published values of timing resolution for these detector materials to tabulate the quantity (efficiency) 2 /(time resolution) which is a measure of the relative sensitivity for time of flight positron tomography

  10. Trepanation and Roman medicine: a comparison of osteoarchaeological remains, material culture and written texts.

    Science.gov (United States)

    Tullo, E

    2010-06-01

    Evidence for prehistoric trepanation is limited to preserved osteoarchaeological material, namely human skulls, and the occasional discovery of surgical instruments. However, the Roman empire gave rise to an abundant and diverse range of source types, including skeletal remains, material culture and detailed medical texts, each of which harbours the potential to contribute to our understanding of trepanation during this historical period. This paper highlights the advantages and inherent biases of each of these source types, and proposes that the simultaneous analysis and integration of different types of historical evidence is essential for the study of trepanation as a surgical procedure.

  11. Stable generator of polydisperse aerosol

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel

    2001-01-01

    Roč. 32, Suppl. 1 (2001), s. S823-S824 ISSN 0021-8502. [European Aerosol Conference 2001. Leipzig, 03.09.2001-07.09.2001] R&D Projects: GA AV ČR IAA4031105 Institutional research plan: CEZ:AV0Z4031919 Keywords : aerosol generator * fine aerosol * polydisperse aerosol Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.605, year: 2001

  12. Comparison of one-dimensional probabilistic finite element method with direct numerical simulation of dynamically loaded heterogeneous materials

    Science.gov (United States)

    Robbins, Joshua; Voth, Thomas

    2011-06-01

    Material response to dynamic loading is often dominated by microstructure such as grain topology, porosity, inclusions, and defects; however, many models rely on assumptions of homogeneity. We use the probabilistic finite element method (WK Liu, IJNME, 1986) to introduce local uncertainty to account for material heterogeneity. The PFEM uses statistical information about the local material response (i.e., its expectation, coefficient of variation, and autocorrelation) drawn from knowledge of the microstructure, single crystal behavior, and direct numerical simulation (DNS) to determine the expectation and covariance of the system response (velocity, strain, stress, etc). This approach is compared to resolved grain-scale simulations of the equivalent system. The microstructures used for the DNS are produced using Monte Carlo simulations of grain growth, and a sufficient number of realizations are computed to ensure a meaningful comparison. Finally, comments are made regarding the suitability of one-dimensional PFEM for modeling material heterogeneity. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. Comparison of the production of solvent based on fossil and renewable raw material with regard to their VOC-emissions

    International Nuclear Information System (INIS)

    Moederl, U.

    1993-10-01

    There are three principle ways for the treatment of phytogenic raw materials: biotechnological processes, pyrolysis and gasification, and the utilisation of phytogenic oils and resins. Because of the last possibility the evaporation times of these compounds were modelled to be able to classify these emissions either natural or not. A rough estimation shows that α-Pinen as the main component of Austrian turpentine oil evaporates within one month - which is much faster than the minimum time for rot. The consequence is that the use of these solvents does not effect the total VOC-emissions because they may be considered as delayed biogenic emissions at different locations. The comparison of the biotechnological processes is done for the following solvents which are also most important basic chemicals for other organic technologies: methanol, ethanol, and methane. The emissions of the production of acetone and butanol can only be estimated in comparison to ethanol. The least amount of VOC-emissions for the production of ethanol is released by using sugar-beet as raw material. The emissions are only insignificantly higher by starting from crude-oil and setting the balance boundaries to Austria. Using wheat is worse and calculating all emissions of the crude-oil processes - including the emissions abroad - is worst. There is no significant difference between conventional and organic farming. (Suda)

  14. Use of the NASA GEOS-5 SEAC4RS Meteorological and Aerosol Reanalysis for assessing simulated aerosol optical properties as a function of smoke age

    Science.gov (United States)

    Randles, C. A.; da Silva, A. M., Jr.; Colarco, P. R.; Darmenov, A.; Buchard, V.; Govindaraju, R.; Chen, G.; Hair, J. W.; Russell, P. B.; Shinozuka, Y.; Wagner, N.; Lack, D.

    2014-12-01

    The NASA Goddard Earth Observing System version 5 (GEOS-5) Earth system model, which includes an online aerosol module, provided chemical and weather forecasts during the SEAC4RS field campaign. For post-mission analysis, we have produced a high resolution (25 km) meteorological and aerosol reanalysis for the entire campaign period. In addition to the full meteorological observing system used for routine NWP, we assimilate 550 nm aerosol optical depth (AOD) derived from MODIS (both Aqua and Terra satellites), ground-based AERONET sun photometers, and the MISR instrument (over bright surfaces only). Daily biomass burning emissions of CO, CO2, SO2, and aerosols are derived from MODIS fire radiative power retrievals. We have also introduced novel smoke "age" tracers, which provide, for a given time, a snapshot histogram of the age of simulated smoke aerosol. Because GEOS-5 assimilates remotely sensed AOD data, it generally reproduces observed (column) AOD compared to, for example, the airborne 4-STAR instrument. Constraining AOD, however, does not imply a good representation of either the vertical profile or the aerosol microphysical properties (e.g., composition, absorption). We do find a reasonable vertical structure for aerosols is attained in the model, provided actual smoke injection heights are not much above the planetary boundary layer, as verified with observations from DIAL/HRSL aboard the DC8. The translation of the simulated aerosol microphysical properties to total column AOD, needed in the aerosol assimilation step, is based on prescribed mass extinction efficiencies that depend on wavelength, composition, and relative humidity. Here we also evaluate the performance of the simulated aerosol speciation by examining in situ retrievals of aerosol absorption/single scattering albedo and scattering growth factor (f(RH)) from the LARGE and AOP suite of instruments. Putting these comparisons in the context of smoke age as diagnosed by the model helps us to

  15. Comparison of Endoflas and Zinc oxide Eugenol as root canal filling materials in primary dentition

    Directory of Open Access Journals (Sweden)

    Nivedita Rewal

    2014-01-01

    Full Text Available Background: Zinc oxide eugenol has long been the material of choice of pediatric dentists worldwide, although it fails to meet the ideal requirements of root canal filling material for primary teeth. Endoflas, a mixture of zinc oxide eugenol, calcium hydroxide, and iodoform, can be considered to be an effective root canal filling material in primary teeth as compared with zinc oxide eugenol. This study was carried out to compare zinc oxide eugenol with endoflas for pulpectomy in primary dentition. Aim: The objective of the study was to compare clinically and radiographically success rates of zinc oxide eugenol with endoflas for the root canal filling of primary teeth at 3, 6, and 9 months. Design: Fifty primary molars were included in the study with 26 teeth in Group I (Endoflas and 24 in Group II (zinc oxide eugenol. A single visit pulpectomy was carried out. Results: The overall success rate of zinc oxide eugenol was 83% whereas 100% success was found in the case of endoflas. The obtained results were compiled and subjected to statistical analysis using the chi-square test. The difference in the success rate between the two was statistically significant (P < 0.05. Conclusion: Endoflas has shown to have better results than zinc oxide eugenol. It should therefore be the material of choice for root canal treatment in deciduous dentition.

  16. Comparison of survivability of Staphylococcus aureus and spores of Aspergillus niger on commonly used floor materials.

    Science.gov (United States)

    Gupta, Mridula; Bisesi, Michael; Lee, Jiyoung

    2017-07-01

    The survivability of Staphylococcus aureus and spores of Aspergillus niger was compared on 5 common floor materials. Floor materials were inoculated with a known concentration of S aureus and spores of A niger on day 0. Their survivability was measured on days, 2, 7, 14, and 28 by bulk rinsate method and enumerated using culture-based method. The difference in change of S aureus levels was statistically significant for all tested days (P niger spores were undetected on residential broadloom carpet and rubber-backed commercial carpet after day 2 but survived on VCT, PT, and wood until day 28. Floor materials with hard and smooth surfaces, such as VCT and PT, can allow survival of S aureus and A niger for up to 4 weeks. It may imply that floor materials can play a major role in preserving microbial contaminants in the built environment. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  17. Density comparison of 3D printing materials and the human body

    Energy Technology Data Exchange (ETDEWEB)

    Savi, M.; Silveira, L.C.; Cechinel, C.M.; Soares, F.A.P., E-mail: Matheus.savi@ifsc.edu.br [Instituo Federal de Santa Catarina (IFSC), Florianópolis (Brazil). Departamento Acadêmico de Saúde e Serviços; Potiens, M.P.A. [Instituto de Pesquisas Energéticas Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil). Lab. de Calibração de Instrumentos

    2017-07-01

    Introduction: Phantoms are commonly used for teaching and radiation dosimetry as a simulator of the human body in order that no individual be exposed to radiation during training and research. Some are the properties that can be used as a measurement parameter in a phantom: density, energy compatibility, attenuation and scattering of the radiation, anthropomorphism, among others. 3D printing has revolutionized many areas of knowledge, including those that make use of radiations. In this context, this study aims to evaluate the density of various materials applied in 3D printing and compare found values with human body density in ICRP 110. Methods: Cubes with 2cm edges were printed on 12 materials of different compositions with internal filling of 60 %, 80% and 100%, weighed on a precision balance and measured with a caliper. Results: The densities found ranged from 0,575 g/cm³ to 2,624 g/cm³ for 60% infill, 0,686 g/cm³ to 3,091 g/cm³ for 80% and 0,794 g/cm³ to 3,572 g/cm³ for 100%. Densities related to teeth, bones, muscles, fat, among others, could be created from specific infill variations. Conclusion: All analyzed materials have the capacity to mimic the structures described in ICRP 110 when the percentage of filling are varied. However, even achieving human tissue density the materials may be not adequate for attenuation and require further experiments. (author)

  18. A comparison of fatigue resistance of three materials for cusp-replacing adhesive restorations.

    NARCIS (Netherlands)

    Kuijs, R.H.; Fennis, W.M.M.; Kreulen, C.M.; Roeters, F.J.M.; Verdonschot, N.J.J.; Creugers, N.H.J.

    2006-01-01

    OBJECTIVES: To investigate the fatigue resistance and failure behaviour of cusp-replacing restorations in premolars using different types of adhesive restorative materials. METHODS: A class 2 cavity was prepared and the buccal cusp was removed in an extracted sound human upper premolar. By using a

  19. Comparison of methods for certification of stannic, stibium and lead traces in reference materials for steel

    Directory of Open Access Journals (Sweden)

    I. V. Khodakovskaya

    2016-01-01

    Full Text Available Development and introduction of new metallurgical technologies, new additional chemical compound indexes controlled in metallurgical materials demand to develop the new, more advanced methods of analytical control. The particular attention should be paid to identify the traces of stannic, stinium and lead because of their influence on metal characteristics.

  20. Density comparison of 3D printing materials and the human body

    International Nuclear Information System (INIS)

    Savi, M.; Silveira, L.C.; Cechinel, C.M.; Soares, F.A.P.; Potiens, M.P.A.

    2017-01-01

    Introduction: Phantoms are commonly used for teaching and radiation dosimetry as a simulator of the human body in order that no individual be exposed to radiation during training and research. Some are the properties that can be used as a measurement parameter in a phantom: density, energy compatibility, attenuation and scattering of the radiation, anthropomorphism, among others. 3D printing has revolutionized many areas of knowledge, including those that make use of radiations. In this context, this study aims to evaluate the density of various materials applied in 3D printing and compare found values with human body density in ICRP 110. Methods: Cubes with 2cm edges were printed on 12 materials of different compositions with internal filling of 60 %, 80% and 100%, weighed on a precision balance and measured with a caliper. Results: The densities found ranged from 0,575 g/cm³ to 2,624 g/cm³ for 60% infill, 0,686 g/cm³ to 3,091 g/cm³ for 80% and 0,794 g/cm³ to 3,572 g/cm³ for 100%. Densities related to teeth, bones, muscles, fat, among others, could be created from specific infill variations. Conclusion: All analyzed materials have the capacity to mimic the structures described in ICRP 110 when the percentage of filling are varied. However, even achieving human tissue density the materials may be not adequate for attenuation and require further experiments. (author)

  1. Material flows and economic models: an analytical comparison of SFA, LCA and partial equilibrium models

    NARCIS (Netherlands)

    Bouman, M.B.; Heijungs, R.; van der Voet, E.; van den Bergh, J.C.J.M.; Huppes, G.

    2000-01-01

    The growing concern for environmental problems in the current economy has spurred the study of the way materials and substances flow through the economy, resulting in many different types of analysis. Since all of these have their merits and shortcomings, much of the present theoretical research

  2. Comparison of material property specifications of austenitic steels in fast breeder reactor technology

    International Nuclear Information System (INIS)

    Vanderborck, Y.; Van Mulders, E.

    1985-01-01

    Austenitic stainless steels are very widely used in components for European Fast Breeder Reactors. The Activity Group Nr.3 ''Materials'', within Working Group ''Codes and Standards'' of the Fast Reactor Co-Ordination Committee of the European Communities, has decided to initiate a study to compare the material property specifications of the austenitic stainless steel used in the European Fast Breeder Technology. Hence, this study would allow one to view rapidly the designation of a particular steel grade in different European countries and to compare given property values for a same grade. There were dissimilarities, differences or voids appear, it could lead to an attempt to complete and/or to uniformize the nationally given values, so that on a practical level interchangeability, availability and use ease design and construction work. A selection of the materials and of their properties has been made by the Working Group. Materials examined are Stainless Steel AISI 304, 304 L, 304 LN, 316, 316 L, 316 LN, 316''Ti stab.'', 316''Nb stab''., 321, 347

  3. Comparison of gap frame designs and materials for precision cathode strip chambers

    International Nuclear Information System (INIS)

    Horvath, J.A.; Pratuch, S.M.; Belser, F.C.

    1993-01-01

    Precision cathode strip chamber perimeter designs that incorporate either continuous or discrete-post gap frames are analyzed. The effects of ten design and material combinations on gravity sag, mass, stress, and deflected shape are evaluated. Procedures are recommended for minimizing mass in the chamber perimeter region while retaining structural integrity and electrical design latitude

  4. Comparison of silicone and spin-on glass packaging materials for light-emitting diode encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Liann-Be; Pan, Ke-Wei; Yen, Chia-Yi [Department of Electronic Engineering and Green Technology Research Center, Chang Gung University, Taoyuan, Taiwan (China); Jeng, Ming-Jer, E-mail: mjjeng@mail.cgu.edu.tw [Department of Electronic Engineering and Green Technology Research Center, Chang Gung University, Taoyuan, Taiwan (China); Wu, Chun-Te; Hu, Sung-Cheng; Kuo, Yang-Kuao [Chemical Systems Research Division, Chung-Shan Institute of Science and Technology Armaments Bureau, MND, Taoyuan, Taiwan (China)

    2014-11-03

    Traditional white light light-emitting diode (LED) encapsulation is performed by mixed phosphors and silicone coating on LED die. However, this encapsulation with silicone coating incurs overheated temperatures and yellowing problem. Therefore, this work attempts to replace silicone paste by using spin-on-glass (SOG) materials. Experimental results indicate that although initial brightness of SOG-based packaging is lower than that of silicone packaging, its light attenuation is significantly lower than that of silicone for a long lighting time. After the LED power is turned on for 12 h, the brightness of LED with silicone and SOG material packaging decreases from 84 to 48 lm and 73 to 59 lm, respectively. Therefore, SOG material provides an alternative packaging solution for high power LED lighting applications. - Highlights: • Spin-on-glass (SOG) material was used to replace silicone coating for LED packaging. • Initial brightness of SOG packaging is lower than that of silicone packaging. • Over time, light attenuation in SOG is much lower than that in silicone. • Color rendering index and brightness of LED packaging was optimized by Taguchi method.

  5. Multiangle Imaging Spectroradiometer (MISR) Global Aerosol Optical Depth Validation Based on 2 Years of Coincident Aerosol Robotic Network (AERONET) Observations

    Science.gov (United States)

    Kahn, Ralph A.; Gaitley, Barbara J.; Martonchik, John V.; Diner, David J.; Crean, Kathleen A.; Holben, Brent

    2005-01-01

    Performance of the Multiangle Imaging Spectroradiometer (MISR) early postlaunch aerosol optical thickness (AOT) retrieval algorithm is assessed quantitatively over land and ocean by comparison with a 2-year measurement record of globally distributed AERONET Sun photometers. There are sufficient coincident observations to stratify the data set by season and expected aerosol type. In addition to reporting uncertainty envelopes, we identify trends and outliers, and investigate their likely causes, with the aim of refining algorithm performance. Overall, about 2/3 of the MISR-retrieved AOT values fall within [0.05 or 20% x AOT] of Aerosol Robotic Network (AERONET). More than a third are within [0.03 or 10% x AOT]. Correlation coefficients are highest for maritime stations (approx.0.9), and lowest for dusty sites (more than approx.0.7). Retrieved spectral slopes closely match Sun photometer values for Biomass burning and continental aerosol types. Detailed comparisons suggest that adding to the algorithm climatology more absorbing spherical particles, more realistic dust analogs, and a richer selection of multimodal aerosol mixtures would reduce the remaining discrepancies for MISR retrievals over land; in addition, refining instrument low-light-level calibration could reduce or eliminate a small but systematic offset in maritime AOT values. On the basis of cases for which current particle models are representative, a second-generation MISR aerosol retrieval algorithm incorporating these improvements could provide AOT accuracy unprecedented for a spaceborne technique.

  6. H{sub 2} storage in microporous materials: a comparison between zeolites and Mos

    Energy Technology Data Exchange (ETDEWEB)

    Ricchiardi, G.; Regli, L.; Vitillo, J. G.; Cocina, D.; Bordiga, S.; Lamberti, C.; Spoto, G.; Zecchina, A.; Bjorgen, M.; Lillerud, K. P.

    2005-07-01

    One of the main concerns about a hydrogen-based energy economy is the efficient storage and transport of this highly flammable gas. Many strategies have been followed or suggested in recent years to solve this problem. The most important ones are: 1) storage in metals and alloys; 2) storage in complex hydrides (alanates, borides); 3) storage by trapping in clathrates (ice and others); 4) storage in microporous materials (carbons, zeolitic materials, metal-organic frameworks, polymers). [1, 2] In this work we have focused our attention on microporous materials, where the crucial point is the strength of the interaction between the molecular hydrogen and the internal surfaces of micropores and/ or of cages of entrapping materials. It is known from fundamental studies that H2 strongly interacts with ions in the gas but that the presence of counterions decreases the interaction energy substantially. The most prominent class of microporous materials, which contains isolated and exposed cations, are zeolites and zeotypes: ideal systems to investigate the interaction of H2 with both dispersive and electrostatic forces [3]. So, even if they are not sufficiently light to represent the final solution to H2 storage, the availability of a large variety of frameworks and chemical compositions combined with low cost and superior mechanical and thermal stabilities increases the interest in these materials. In this work we have studied in detail, by means of volumetric and spectroscopic measurements, zeolites with CHA topology (as they are characterized by a strong acidity and by a big surface area). H-SSZ-13 zeolite, characterized by a low Al content (Si/Al = 11), has shown the best properties in hydrogen storage in respect to all the other zeolites and zeotypes with different compositions and topologies [4]. The results have been compared with those obtained for MOF-5 [5], a well known Metal-Organic Framework, indicated as a very good material for molecular hydrogen storage [6

  7. Reducing Respiratory Health Risks to Horses and Workers: A Comparison of Two Stall Bedding Materials

    Directory of Open Access Journals (Sweden)

    Markku Saastamoinen

    2015-10-01

    Full Text Available Stable air quality and the choice of bedding material are an important health issue both in horses and people working or visiting horse stables. Risks of impaired respiratory health are those that can especially be avoided by improving air quality in the stable. The choice of bedding material is particularly important in cold climate conditions; where horses are kept most of the day and year indoors throughout their life. This study examined the effect of two bedding materials; wood shavings and peat; on stable air quality and health of horses. Ammonia and dust levels were also measured to assess conditions in the stable. Ammonia was not detected or was at very low levels (<0.25 ppm in the boxes in which peat was used as bedding; but its concentration was clearly higher (1.5–7.0 ppm in stalls with wood shavings as bedding. Personal measurements of workers revealed quite high ammonia exposure (5.9 ppm8h in the boxes in which wood shavings were used; but no exposure was Animals 2015, 5 966 observed in stalls bedded with peat. The respiratory symptoms in horses increased regardless of the bedding material at the beginning of the study. The health status of the horses in the peat bedding group returned to the initial level in the end of the trial but horses bedded with wood shavings continued to be symptomatic. The hooves of the horses with peat bedding had a better moisture content than those of the horses bedded with wood shavings. The results suggest that peat is a better bedding material for horses than wood shavings regarding the health of both horses and stable workers.

  8. Code Development on Fission Product Behavior under Severe Accident-Validation of Aerosol Sedimentation

    International Nuclear Information System (INIS)

    Ha, Kwang Soon; Kim, Sung Il; Jang, Jin Sung; Kim, Dong Ha

    2016-01-01

    The gas and aerosol phases of the radioactive materials move through the reactor coolant systems and containments as loaded on the carrier gas or liquid, such as steam or water. Most radioactive materials might escape in the form of aerosols from a nuclear power plant during a severe reactor accident, and it is very important to predict the behavior of these radioactive aerosols in the reactor cooling system and in the containment building under severe accident conditions. Aerosols are designated as very small solid particles or liquid droplets suspended in a gas phase. The suspended solid or liquid particles typically have a range of sizes of 0.01 m to 20 m. Aerosol concentrations in reactor accident analyses are typically less than 100 g/m3 and usually less than 1 g/m3. When there are continuing sources of aerosol to the gas phase or when there are complicated processes involving engineered safety features, much more complicated size distributions develop. It is not uncommon for aerosols in reactor containments to have bimodal size distributions for at least some significant periods of time early during an accident. Salient features of aerosol physics under reactor accident conditions that will affect the nature of the aerosols are (1) the formation of aerosol particles, (2) growth of aerosol particles, (3) shape of aerosol particles. At KAERI, a fission product module has been developed to predict the behaviors of the radioactive materials in the reactor coolant system under severe accident conditions. The fission product module consists of an estimation of the initial inventories, species release from the core, aerosol generation, gas transport, and aerosol transport. The final outcomes of the fission product module designate the radioactive gas and aerosol distribution in the reactor coolant system. The aerosol sedimentation models in the fission product module were validated using ABCOVE and LACE experiments. There were some discrepancies on the predicted

  9. Code Development on Fission Product Behavior under Severe Accident-Validation of Aerosol Sedimentation

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Kwang Soon; Kim, Sung Il; Jang, Jin Sung; Kim, Dong Ha [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The gas and aerosol phases of the radioactive materials move through the reactor coolant systems and containments as loaded on the carrier gas or liquid, such as steam or water. Most radioactive materials might escape in the form of aerosols from a nuclear power plant during a severe reactor accident, and it is very important to predict the behavior of these radioactive aerosols in the reactor cooling system and in the containment building under severe accident conditions. Aerosols are designated as very small solid particles or liquid droplets suspended in a gas phase. The suspended solid or liquid particles typically have a range of sizes of 0.01 m to 20 m. Aerosol concentrations in reactor accident analyses are typically less than 100 g/m3 and usually less than 1 g/m3. When there are continuing sources of aerosol to the gas phase or when there are complicated processes involving engineered safety features, much more complicated size distributions develop. It is not uncommon for aerosols in reactor containments to have bimodal size distributions for at least some significant periods of time early during an accident. Salient features of aerosol physics under reactor accident conditions that will affect the nature of the aerosols are (1) the formation of aerosol particles, (2) growth of aerosol particles, (3) shape of aerosol particles. At KAERI, a fission product module has been developed to predict the behaviors of the radioactive materials in the reactor coolant system under severe accident conditions. The fission product module consists of an estimation of the initial inventories, species release from the core, aerosol generation, gas transport, and aerosol transport. The final outcomes of the fission product module designate the radioactive gas and aerosol distribution in the reactor coolant system. The aerosol sedimentation models in the fission product module were validated using ABCOVE and LACE experiments. There were some discrepancies on the predicted

  10. Aerosols, clouds and radiation

    Energy Technology Data Exchange (ETDEWEB)

    Twomey, S [University of Arizona, Tucson, AZ (USA). Inst. of Atmospheric Physics

    1991-01-01

    Most of the so-called 'CO{sub 2} effect' is, in fact, an 'H{sub 2}O effect' brought into play by the climate modeler's assumption that planetary average temperature dictates water-vapor concentration (following Clapeyron-Clausius). That assumption ignores the removal process, which cloud physicists know to be influenced by the aerosol, since the latter primarily controls cloud droplet number and size. Droplet number and size are also influential for shortwave (solar) energy. The reflectance of many thin to moderately thick clouds changes when nuclei concentrations change and make shortwave albedo susceptible to aerosol influence.

  11. A stratospheric aerosol increase

    Science.gov (United States)

    Rosen, J. M.; Hofmann, D. J.

    1980-01-01

    Large disturbances were noted in the stratospheric aerosol content in the midlatitude Northern Hemisphere commencing about 7 months after the eruption of La Soufriere and less than 1 month after the eruption of Sierra Negra. The aerosol was characterized by a very steep size distribution in the 0.15 to 0.25 micron radius range and contained a volatile component. Measurements near the equator and at the South Pole indicate that the disturbance was widespread. These observations were made before the May 18 eruption of Mt. St. Helens.

  12. Radon dose and aerosols

    International Nuclear Information System (INIS)

    Planinic, J.; Radolic, V.; Faj, Z.; Vukovic, B.

    2000-01-01

    The equilibrium factor value (F) was measured in the NRPB radon chamber and the corresponding track density ratio (r = D/D 0 ) of bare (D) and diffusion (D 0 ) LR-115 nuclear track detectors was determined, as well as the regression equation F(r). Experiments with LR-115 nuclear track detectors and aerosol sources (burning candle and cigarette) were carried out in the Osijek University radon chamber and afterwards an empirical relationship between the equilibrium factor and aerosol concentration was derived. For the purpose of radon dose equivalent assessment, procedures for determining the unattached fraction of radon progeny were introduced using two nuclear track detectors. (author)

  13. Stratospheric Aerosol Measurements

    Science.gov (United States)

    Pueschel, Rudolf, F.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric aerosols affect the atmospheric energy balance by scattering and absorbing solar and terrestrial radiation. They also can alter stratospheric chemical cycles by catalyzing heterogeneous reactions which markedly perturb odd nitrogen, chlorine and ozone levels. Aerosol measurements by satellites began in NASA in 1975 with the Stratospheric Aerosol Measurement (SAM) program, to be followed by the Stratospheric Aerosol and Gas Experiment (SAGE) starting in 1979. Both programs employ the solar occultation, or Earth limb extinction, techniques. Major results of these activities include the discovery of polar stratospheric clouds (PSCs) in both hemispheres in winter, illustrations of the impacts of major (El Chichon 1982 and Pinatubo 1991) eruptions, and detection of a negative global trend in lower stratospheric/upper tropospheric aerosol extinction. This latter result can be considered a triumph of successful worldwide sulfur emission controls. The SAGE record will be continued and improved by SAGE III, currently scheduled for multiple launches beginning in 2000 as part of the Earth Observing System (EOS). The satellite program has been supplemented by in situ measurements aboard the ER-2 (20 km ceiling) since 1974, and from the DC-8 (13 km ceiling) aircraft beginning in 1989. Collection by wire impactors and subsequent electron microscopic and X-ray energy-dispersive analyses, and optical particle spectrometry have been the principle techniques. Major findings are: (1) The stratospheric background aerosol consists of dilute sulfuric acid droplets of around 0.1 micrometer modal diameter at concentration of tens to hundreds of monograms per cubic meter; (2) Soot from aircraft amounts to a fraction of one percent of the background total aerosol; (3) Volcanic eruptions perturb the sulfuric acid, but not the soot, aerosol abundance by several orders of magnitude; (4) PSCs contain nitric acid at temperatures below 195K, supporting chemical hypotheses

  14. Aerosol Size and Chemical Composition in the Canadian High Arctic

    Science.gov (United States)

    Chang, R. Y. W.; Hayes, P. L.; Leaitch, W. R.; Croft, B.; O'Neill, N. T.; Fogal, P.; Drummond, J. R.; Sloan, J. J.

    2015-12-01

    Arctic aerosol have a strong annual cycle, with winter months dominated by long range transport from lower latitudes resulting in high mass loadings. Conversely, local emissions are more prominent in the summer months because of the decreased influence of transported aerosol, allowing us to regularly observe both transported and local aerosol. This study will present observations of aerosol chemical composition and particle number size distribution collected at the Polar Environment Artic Research Laboratory and the Alert Global Atmospheric Watch Observatory at Eureka (80N, 86W) and Alert (82N, 62W), Nunavut, respectively. Summer time observations of the number size distribution reveal a persistent mode of particles centered between 30-50 nm, with occasional bursts of smaller particles. The non-refractory aerosol chemical composition, measured by the Canadian Network for the Detection of Atmospheric Change quadrupole aerosol mass spectrometer, is primarily organic, with contributions from both aged and fresher organic aerosol. Factor analysis will be conducted to better understand these sources. The site at Eureka is more susceptible to long range transport since it is at the top of a mountain ridge (610 m above sea level) and will be compared to the site at Alert on an elevated plain (200 m above sea level). This will allow us to determine the relative contributions from processes and sources at the sites at different elevations. Comparisons with aerosol optical depth and GEOS-Chem model output will also be presented to put these surface measurements into context with the overlying and regional atmosphere. Results from this study contribute to our knowledge of aerosol in the high Arctic.

  15. A Comparison of Materials Issues for Cermet and Graphite-Based NTP Fuels

    Science.gov (United States)

    Stewart, Mark E.; Schnitzler, Bruce G.

    2013-01-01

    This paper compares material issues for cermet and graphite fuel elements. In particular, two issues in NTP fuel element performance are considered here: ductile to brittle transition in relation to crack propagation, and orificing individual coolant channels in fuel elements. Their relevance to fuel element performance is supported by considering material properties, experimental data, and results from multidisciplinary fluid/thermal/structural simulations. Ductile to brittle transition results in a fuel element region prone to brittle fracture under stress, while outside this region, stresses lead to deformation and resilience under stress. Poor coolant distribution between fuel element channels can increase stresses in certain channels. NERVA fuel element experimental results are consistent with this interpretation. An understanding of these mechanisms will help interpret fuel element testing results.

  16. Comparison of actual and predicted routes used in the shipment of radioactive materials

    International Nuclear Information System (INIS)

    Joy, D.S.; Johnson, P.E.; Harrison, I.G.

    1985-01-01

    A number of highway controlled shipments of radioactive materials have been made over the past several years. An excellent example showing the variability of actual routes is the transfer of 45 shipments between the Three Mile Island reactor in Pennsylvania and Scoville, Idaho in 1982 and 1983. Six different routes varying between 2273 and 2483 miles were used. Approximately 75% of these shipments followed a common route which passed through ten Urbanized Areas, defined by the Census Bureau as having a population exceeding 100,000 people. Other routes, while shorter in distance, passed through as many as 14 Urbanized Areas. Routes predicted by the Oak Ridge routing model did not exactly duplicate actual routes used. However, the analysis shows that the routing model does make a good estimate of transportation routes actually chosen by shippers of radioactive materials. In actual practice, a number of factors (weather, road conditions, driver preference, etc.) influence the actual route taken. 5 refs., 1 fig., 1 tab

  17. Comparison of glass surfaces as a countertop material to existing surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Turo, Laura A.; Winschell, Abigail E.

    2011-09-01

    Gleen Glass, a small production glass company that creates countertops, was selected for the Technology Assistance Program through Pacific Northwest National Laboratory. Gleen Glass was seeking material property analysis comparing glass as a countertop material to current surfaces (i.e. marble, granite and engineered stone). With samples provided from Gleen Glass, testing was done on granite, marble, and 3 different glass surfaces ('Journey,' 'Pebble,' and 'Gleen'). Results showed the glass surfaces have a lower density, lower water absorption, and are stronger in compressive and flexural tests as compared to granite and marble. Thermal shock tests showed the glass failed when objects with a high thermal mass are placed directly on them, whereas marble and granite did not fracture under these conditions.

  18. Crack propagation in teeth: a comparison of perimortem and postmortem behavior of dental materials and cracks.

    Science.gov (United States)

    Hughes, Cris E; White, Crystal A

    2009-03-01

    This study presents a new method for understanding postmortem heat-induced crack propagation patterns in teeth. The results demonstrate that patterns of postmortem heat-induced crack propagation differ from perimortem and antemortem trauma-induced crack propagation patterns. Dental material of the postmortem tooth undergoes dehydration leading to a shrinking and more brittle dentin material and a weaker dentin-enamel junction. Dentin intertubule tensile stresses are amplified by the presence of the pulp cavity, and initiates crack propagation from the internal dentin, through the dentin-enamel junction and lastly the enamel. In contrast, in vivo perimortem and antemortem trauma-induced crack propagation initiates cracking from the external surface of the enamel toward the dentin-enamel junction where the majority of the energy of the crack is dissipated, eliminating the crack's progress into the dentin. These unique patterns of crack propagation can be used to differentiate postmortem taphonomy-induced damage from antemortem and perimortem trauma in teeth.

  19. Comparison of waste pumpkin material and its potential use in extruded snack foods.

    Science.gov (United States)

    Norfezah, M N; Hardacre, A; Brennan, C S

    2011-08-01

    Material was produced from Crown pumpkin (Cucurbita maxima) processed from fractions of the fruit which are regarded as waste stream products (peel, flesh and seed). The flour from the three different fractions (peel, flesh and seed) of Crown pumpkin flour was incorporated into an extruded snack product formulation at levels 10%, 30% and 50% (w/w with corn grit) and processed in a twin-screw extruder to make 10 expanded snack products. Proximate analysis was carried out to determine the nutritional value of the raw pumpkin and pumpkin flour. A physical analysis of the product was used to determine its color, the expansion ratio, bulk density and texture. Inclusion of waste stream material (peel and seed) at 10%, yielded extruded products with similar expansion and density characteristics to the control sample; however, an inclusion of greater than 10% yielded significant challenges to product quality (hardness of the product).

  20. Comparison of Ablation Predictions for Carbonaceous Materials Using CEA and JANAF-Based Species Thermodynamics

    Science.gov (United States)

    Milos, Frank S.

    2011-01-01

    In most previous work at NASA Ames Research Center, ablation predictions for carbonaceous materials were obtained using a species thermodynamics database developed by Aerotherm Corporation. This database is derived mostly from the JANAF thermochemical tables. However, the CEA thermodynamics database, also used by NASA, is considered more up to date. In this work, the FIAT code was modified to use CEA-based curve fits for species thermodynamics, then analyses using both the JANAF and CEA thermodynamics were performed for carbon and carbon phenolic materials over a range of test conditions. The ablation predictions are comparable at lower heat fluxes where the dominant mechanism is carbon oxidation. However, the predictions begin to diverge in the sublimation regime, with the CEA model predicting lower recession. The disagreement is more significant for carbon phenolic than for carbon, and this difference is attributed to hydrocarbon species that may contribute to the ablation rate.