Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

International Nuclear Information System (INIS)

Jordan, S.; Schikarski, W.; Schoeck, W.

1977-01-01

The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters

Collection of aerosols in high efficiency particulate air filters

International Nuclear Information System (INIS)

Pratt, R.P.; Green, B.L.

1987-01-01

The investigation of the performance of HEPA filters of both minipleat and conventional deep pleat designs has continued at Harwell. Samples of filters from several manufacturers have been tested against the UKAEA/BNF plc filter purchasing specification. No unexpected problems have come to light in these tests, apart from some evidence to suggest that although meeting the specification minipleat filters are inherently weaker in burst strength terms than conventional filters. In addition tests have been carried out to investigate the dust loading versus pressure drop characteristics of both designs of filters using a range of test dusts - ASHRAE dust, carbon black, BS 2831 No. 2 test dust and sodium chloride. In parallel with laboratory test work a more fundamental study on the effects of geometric arrangement of filter media within the filter frame has been carried out on behalf of the UKAEA by Loughborough University. The results of this study has been the development of a mathematical model to predict the dust load versus pressure drop characteristic as a function of filter media geometry. This has produced good agreement with laboratory test results using a challenge aerosol in the 1-5 μm size range. Further observations have been made to enhance understanding of the deposition of aerosols within the filter structure. The observations suggest that the major influence on dust loading is the depth of material collected in the flow channel as a surface deposition, and this explains the relatively poor performance of the minipleat design of filter

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

Tests at Oak Ridge National Laboratory confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter medium, identical to that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.97 percent quoted for ordinary particulate matter have been observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers, by the alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow. Dependence on the air flow velocity is slight. It appears that this phenomenon has not been observed in previous experiments with alpha-active aerosols because the tests did not continue for a sufficiently long time. A theoretical model of the process has been developed, amenable to computer handling, that should allow calculation of the rate constants associated with the transfer through and release of radioactive material from a filter system by this process

Development of aerosol decontamination factor evaluation method for filtered containment venting system

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae bong; Kim, Sung Il; Jung, Jaehoon; Ha, Kwang Soon; Kim, Hwan Yeol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

Fission products would be released from molten corium pools which are relocated into the lower plenum of reactor pressure vessel, on the concrete pit and in the core catcher. In addition, steam, hydrogen and noncondensable gases such as CO and CO2 are generated during the core damage progression due to loss of coolant and the molten core-concrete interaction. Consequently, the pressure inside the containment could be increased continuously. Filtered containment venting is one action to prevent an uncontrolled release of radioactive fission products caused by an overpressure failure of the containment. After the Fukushima-Daiichi accident which was demonstrated the containment failure, many countries to consider the implementation of filtered containment venting system(FCVS) on nuclear power plant where these are not currently applied. In general evaluation for FCVS is conducted to determine decontamination factor on several conditions (aerosol diameter, submergence depth, water temperature, gas flow, steam flow rate, pressure, operating time,...). It is essential to quantify the mass concentration before and after FCVS for decontamination factor. This paper presents the development of the evaluation facility for filtered containment venting system at KAERI and an experimental investigation for aerosol removal performance. Decontamination factor for the FCVS is determined by filter measurement. The result of the aerosol size distribution measurement shows the aerosol removal performance by an aerosol size.

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).

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).

Reentrainment of aerosols during the filtered venting after a severe core melt accident

International Nuclear Information System (INIS)

Mueller, M.

1997-01-01

The major objective of this project is the experimental determination of the aerosol reentrainment from boiling pool during controlled filtered venting of the containment vessel after a severe core melt accident. For this reason a linear downscaled (1:20) model containment with an inner free volume of 5 m 3 is provided. Both, water soluble and unsoluble model substances are used as fission product simulants. The major advantage of the pilot plant is the ability to run it at steady state conditions of any period of time. Further, modelling of the aerosol reentrainment from boiling pool allows upscaling of results on nuclear power plants. The deterministic aerosol reentrainment model can also be used to calculate entrainment phenomena in the process industries such at distillation columns or at flash evaporators. Steady state experiments with water soluble model substances clearly reveal enhanced aerosol reentrainment from boiling pool due to increasing boiling pool concentration of fission product simulants and due to increasing gas velocities above the boiling pool surface. But there can be seen no influence of corium concrete interactions on the aerosol reentrainment. Compared to the steam production due to the decay heat the resulting gas volume flux is negligible. Next, there can be seen aerosol reentrainment from boiling pool only above boiling pool areas. Further, experiments under steady state conditions with unsoluble fission product simulants show on the one hand scrubbing effects in the boiling pool, on the other hand no aerosol reentrainment of solid particles 3 μm. The so called reentrainment factor - ratio between fission product simulant in the venting system and in the boiling pool - is for water soluble model substances in the range of 10 -5 , for unsoluble fission product simulants in the range of 10 -6 . (author) figs., tabs., 57 refs

Deposition of Aerosol Particles in Electrically Charged Membrane Filters

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1972-05-15

A theory for the influence of electric charge on particle deposition on the surface of charged filters has been developed. It has been tested experimentally on ordinary membrane filters and Nuclepore filters of 8 mum pore size, with a bipolar monodisperse test aerosol of 1 mum particle diameter, and at a filter charge up to 20 muC/m2. Agreement with theory was obtained for the Coulomb force between filter and particle for both kinds of filters. The image force between charged filter and neutral particles did not result in the predicted deposition in the ordinary membrane filter, probably due to lacking correspondence between the filter model employed for the theory, and the real filter. For the Nuclepore filter a satisfactory agreement with theory was obtained, also at image interaction

Study of the stopping power of various filters

International Nuclear Information System (INIS)

Madelaine, G.

1964-01-01

The first part is devoted to a study of aerosols obtained from the combustion of various smoke-producing compounds. A trial aerosol of which the size distribution is the closest possible to that of atmospheric dusts has been defined. The efficiency of various filters has been determined for successive increments of the dimensions and not for the whole range of its diameter distribution. The variation in the efficiency of the filtering layers as a function of the filtering speed and particle size has been studied for aerosols having particle diameters of over 0.3 μ. The second part describes an original method for measuring the efficiency of filters for ultra-fine particles (under 0.1 μ) using the fixation properties of radioactive atoms resulting from the decay of thoron. (author) [fr

Aerosol characterization in a gas mantel factory

International Nuclear Information System (INIS)

Cunha, K.D. da; Moura, J.J.; Simoes, F.; d'Oliveira, D.; Leite, V.C.B.; Alves, Rex N.; Silva, I.C.M. da.

1997-01-01

The workers in a gas mantel manufacturing are exposed to aerosol containing Th and it decay products, which are hazardous to health. For health damage evaluation it is necessary to determine the inhaled particle size, the Th and thoron concentration in the aerosol breathing fraction. A cascade impactor, a stack filter unit and individual air sampler were used to characterize the airborne particles containing Th. The thoron and radon air concentration were determined using Tsivoglu, Kusnetz, Rolle and Two filters methods. (author). 5 refs., 1 fig., 1 tab

Penetration of HEPA-filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.P.

1977-01-01

Results of work confirming that alpha-emitting particulate matter penetrates high-efficiency filter media much more effectively than do nonradioactive or beta-gamma-active aerosols are reported. Filter retention efficiencies appreciably lower than the 99.97% expected for ordinary particulate matter have been observed with 212 Pb, 253 Es, 238 Pu and 239 Pu sources, indicating that the phenomenon is common to all of these. Similar amounts of a beta-gamma-active material placed in the test filter system showed no migration, but when homogeneously mixed with alpha-active material, the gamma activity migrated along with the alpha material. (U.K.)

The influence of the group delay of digital filters on acoustic decay measurements

DEFF Research Database (Denmark)

Sobreira-Seoane, Manuel A.; Cabo, David Pérez; Jacobsen, Finn

2012-01-01

In this paper the error due to the phase response of digital filters on acoustic decay measurements is analyzed. There are two main sources of errors when an acoustic decay is filtered: the error due to the bandwidth of the filters related to their magnitude response, and the error due to their p...

A method of alpha-radiating nuclide activity measuring in aerosol filters

International Nuclear Information System (INIS)

Ignatov, V.P.; Galkina, V.N.

1992-01-01

Scintillation method of determination of alpha-radiating nuclide activity in aerosol filters was suggested. The method involves dissolution of the filter in organic solvent, introduction of luminophore into solution prepared, drying of the preparation and measurement of radionuclide activity. Dependences of alpha-radiation detection efficiency on the content of luminophore, filter material, colourless and coloured substances in preparations analyzed were considered

Calculation of aerodynamics of aerosol filter designs for cleaning of heavy liquid metal cooler reactor gas loops

International Nuclear Information System (INIS)

Valery P Melnikov; Pyotr N Martynov; Albert K Papovyants; Ivan V Yagodkin

2005-01-01

Full text of publication follows: One of the basic performances of aerosol filters is the aerodynamic resistance to the flow of gaseous medium to be cleaned. Calculation of the aerodynamics of aerosol filters in reference to the gas loops of reactor installations with heavy liquid metal coolant (HLMC) allows the design of the structural components of filters to be optimized to provide minimum initial resistance values. It is established that owing to various factors aerosol particles of different concentration and disperse composition are present always in the gas spaces of heavy liquid metal cooled reactor gas loops. To prevent the negative effect of aerosols on the equipment of the gas loops, it is reasonable to use filters of multistep design with sections of preliminary and fine cleaning to catch micron and submicron particles, respectively. A computer program and technique have been developed to evaluate the aerodynamics of folded aerosol filters for different parameters of their structural components, taking account of the aerosol spectrum and concentration. The algorithm of the calculation is presented by the example of a two-step design assembled in single vessel; the filter dimensions and pattern of the air flow to be cleaned are determined under the given boundary conditions. The evaluation of the aerodynamic resistance of filters was performed with consideration for local resistances and resistances of all the structural components of the filter (sudden constriction, expansion, the flow in air channels, filtering material and so on). Correlations have been derived for the resistance of air channels, filtering materials of preliminary and fine cleaning sections as a function of such parameters as the section depth (50-500 mm), the height of separators (3,5-20 mm), the filtering surface area (1,5-30 m 2 ). Based on the calculation results, the auto-similarity domain was brought out for the minimal values of filter resistances as a function of the ratio of

Aerosols radioactivity in the Bratislava atmosphere

International Nuclear Information System (INIS)

Sykora, I.; Chudy, M.; Durana, L.; Holy, K.; Meresova, J.

2001-01-01

In our laboratory we measured temporal variation of 7 Be concentration in the atmosphere in period 1977 -1994 years. The aerosols were collected through every month at Hydrometeorological Institute in Bratislava-Koliba, latitude 48 grad 10' and altitude 286 m above sea level. Since end of year 2000 we have started to continue monitoring radioactivity of atmosphere aerosols in new locality in Bratislava-Mlynska dolina. Beside 7 Be we measured also 210 Pb radionuclide aerosols concentration. For measured values 7 Be concentrations are considered corrections for decay radionuclide during the time of filters collection, time between end of collection and measurement and decay during the time of measurement. Obtained results for 7 Be concentrations in aerosols shows seasonal summer maximum, but for 210 Pb concentration in aerosols the seasonal variations are not evident. The temporal variations of this radionuclide which is originated in ground-level atmosphere are more sensitive on meteorological factors and can be also influenced by the industrial activity. For better understanding is needed long term monitoring. (authors)

Development of Aerosol Scrubbing Test Loop for Containment Filtered Venting System

International Nuclear Information System (INIS)

Lee, Doo Yong; Jung, Woo Young; Lee, Hyun Chul; Lee, Jong Chan; Kim, Gyu Tae

2016-01-01

The scrubber tank is filled with scrubbing water with the chemical additives. The droplet separator based on a cyclone is installed above the scrubbing water pool to remove the large droplets that may clog a metal fiber filter installed at the upper section of the scrubber tank. The outlet piping is connected from the scrubber tank to the molecular sieve to chemically remove the gaseous iodine. The aerosol as a particle is physically captured in the scrubbing water pool passing through the scrubbing nozzle as well as the metal fiber filter. The gaseous iodine such as molecular iodine as well as organic iodide is chemically removed in the scrubbing water pool and molecular sieve. The thermal-hydraulic as well as scrubbing performance for the CFVS should be verified with the experiments. The experiment can be divided into the filtration component based experiment and whole system based one. In this paper, the aerosol scrubbing test loop developed to test the thermal-hydraulic and aerosol scrubbing performance of the scrubbing nozzle with the scrubbing water pool is introduced. The aerosol scrubbing test loop has been developed as a part of the Korean CFVS project. In this loop, the filtration components such as the scrubbing nozzle submerged in the scrubbing water pool as well as the cyclone as droplet separator can be tested under the CFVS operating conditions. The aerosol scrubbing performance of the filtration components including pool scrubbing behavior can be tested with the aerosol generation and feeding system and aerosol measurement system.

Development of Aerosol Scrubbing Test Loop for Containment Filtered Venting System

Energy Technology Data Exchange (ETDEWEB)

Lee, Doo Yong; Jung, Woo Young; Lee, Hyun Chul; Lee, Jong Chan; Kim, Gyu Tae [FNC Technology, Yongin (Korea, Republic of)

2016-05-15

The scrubber tank is filled with scrubbing water with the chemical additives. The droplet separator based on a cyclone is installed above the scrubbing water pool to remove the large droplets that may clog a metal fiber filter installed at the upper section of the scrubber tank. The outlet piping is connected from the scrubber tank to the molecular sieve to chemically remove the gaseous iodine. The aerosol as a particle is physically captured in the scrubbing water pool passing through the scrubbing nozzle as well as the metal fiber filter. The gaseous iodine such as molecular iodine as well as organic iodide is chemically removed in the scrubbing water pool and molecular sieve. The thermal-hydraulic as well as scrubbing performance for the CFVS should be verified with the experiments. The experiment can be divided into the filtration component based experiment and whole system based one. In this paper, the aerosol scrubbing test loop developed to test the thermal-hydraulic and aerosol scrubbing performance of the scrubbing nozzle with the scrubbing water pool is introduced. The aerosol scrubbing test loop has been developed as a part of the Korean CFVS project. In this loop, the filtration components such as the scrubbing nozzle submerged in the scrubbing water pool as well as the cyclone as droplet separator can be tested under the CFVS operating conditions. The aerosol scrubbing performance of the filtration components including pool scrubbing behavior can be tested with the aerosol generation and feeding system and aerosol measurement system.

A new method for in-situ filter testing using pulses of aerosol and photometric detection with computer control

International Nuclear Information System (INIS)

Marshall, P.R.C.; Bosley, R.B.

1993-01-01

This paper describes a new technique, developed at the Harwell Laboratory, for the in-situ testing of High Efficiency Particulate Air (HEPA) filters using multiple pulses of test aerosol. The pulse test apparatus consists of a modified forward light scattering photometer coupled to a portable micro-computer fitted with an external data acquisition and control card. The micro-computer switches an aerosol generator on and off via an external relay driver unit. Using this apparatus the filter bank is challenged by a small number of equal length, constant concentration, pulses of aerosol at timed intervals. The aerosol concentration data upstream of the filter bank is logged, to disk, by the computer. The process is then repeated for the downstream concentration with the photometer gain increased to give maximum sensitivity. The collected data is analysed using a computer spread-sheet package; the recorded aerosol pulses are combined, integrated and the background data subtracted; the downstream data is then divided by the upstream pulse data to give the filter penetration. Using this technique the sensitivity of the in-situ filter test has been greatly improved, penetrations approaching 10 -5 % can now be measured, allowing HEPA filters mounted in series to be successfully tested. In addition, filter loading is reduced considerably

Kalman filter approach for uncertainty quantification in time-resolved laser-induced incandescence.

Science.gov (United States)

Hadwin, Paul J; Sipkens, Timothy A; Thomson, Kevin A; Liu, Fengshan; Daun, Kyle J

2018-03-01

Time-resolved laser-induced incandescence (TiRe-LII) data can be used to infer spatially and temporally resolved volume fractions and primary particle size distributions of soot-laden aerosols, but these estimates are corrupted by measurement noise as well as uncertainties in the spectroscopic and heat transfer submodels used to interpret the data. Estimates of the temperature, concentration, and size distribution of soot primary particles within a sample aerosol are typically made by nonlinear regression of modeled spectral incandescence decay, or effective temperature decay, to experimental data. In this work, we employ nonstationary Bayesian estimation techniques to infer aerosol properties from simulated and experimental LII signals, specifically the extended Kalman filter and Schmidt-Kalman filter. These techniques exploit the time-varying nature of both the measurements and the models, and they reveal how uncertainty in the estimates computed from TiRe-LII data evolves over time. Both techniques perform better when compared with standard deterministic estimates; however, we demonstrate that the Schmidt-Kalman filter produces more realistic uncertainty estimates.

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

Science.gov (United States)

Bezek, M.; Gregorič, A.; Vaupotič, J.

2013-03-01

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

Flame generation of sodium chloride aerosol for filter testing

International Nuclear Information System (INIS)

Edwards, J.; Kinnear, D.I.

1975-01-01

A generator for sodium chloride aerosol is described, which when used in conjunction with a sensitive portable sodium flame detector unit, will permit the in-place testing of large filter installations having air throughputs up to about 80,000 m 3 /h, at penetrations down to at least 0.005 percent. (U.S.)

Characterisation of non-aerosol-bound fractions of radon decay products under environmental conditions

International Nuclear Information System (INIS)

Pagelkopf, P.; Porstendoerfer, J.

2004-01-01

Dose-relevant factors such as the concentration and size distribution of radon decay products are strongly influenced by the charge-carrying fraction and state of charge of the first radon decay product, 2 18Po. The charge of 2 18Po influences its own mobility and hence its attachment to aerosols and deposition on surfaces, also referred to as ''plating out''. The mobility of 2 18Po can be described in terms of its diffusion coefficient. The goal of the present study was to determine theoretically as well as practically the charge-carrying fraction of radon decay products 2 18Po and 2 14Pb under room air conditions and to design and construct an electrical mobility spectrometer. The spatial model developed by Jacobi and modified by Porstendoerfer for calculating the concentration of unattached radon decay products in indoor and outdoor air under steady-state conditions was extended to permit a differentiated description of the charge-carrying and neutral unattached fractions of radon decay products 2 18Po and 2 14Pb. An 8 m 2 chamber permitting chamber air control in terms of radon gas concentration and humidity was built in order to study the behaviour of radon decay products. The charge-carrying fraction of unattached radon decay products 218 Po and 214 Pb was measured in this chamber. A technique referred to as the online backscreen technique (OBST) was developed to permit the continuous measurement of unattached decay products. The technique involves the diffusive deposition of unattached radon decay products from a laminar flow onto a wire lattice and their subsequent measurement. The total fraction of decay products is then determined by means of the filtration method. Furthermore, all parameters required for modelling such as radon gas, decay product and aerosol concentrations as well as air humidity, temperature and ion dose rate were measured [de

Method for HEPA filter leak scanning with differentiating aerosol detector

Energy Technology Data Exchange (ETDEWEB)

Kovach, B.J.; Banks, E.M.; Wikoff, W.O. [NUCON International, Inc., Columbus, OH (United States)

1997-08-01

While scanning HEPA filters for leaks with {open_quotes}Off the Shelf{close_quote} aerosol detection equipment, the operator`s scanning speed is limited by the time constant and threshold sensitivity of the detector. This is based on detection of the aerosol density, where the maximum signal is achieved when the scanning probe resides over the pinhole longer than several detector time-constants. Since the differential value of the changing signal can be determined by observing only the first small fraction of the rising signal, using a differentiating amplifier will speed up the locating process. The other advantage of differentiation is that slow signal drift or zero offset will not interfere with the process of locating the leak, since they are not detected. A scanning hand-probe attachable to any NUCON{reg_sign} Aerosol Detector displaying the combination of both aerosol density and differentiated signal was designed. 3 refs., 1 fig.

Theoretical aspects of an electrostatic aerosol filter for civilian turbofan engines

Directory of Open Access Journals (Sweden)

Valeriu DRAGAN

2012-03-01

Full Text Available The paper addresses the problem of aerosol filtration in turbofan engines. The current problem of very fine aerosol admission is the impossibility for mechanical filtration; another aspect of the problem is the high mass flow of air to be filtered. Non-attended, the aerosol admission can -and usually does- lead to clogging of turbine cooling passages and can damage the engine completely. The approach is theoretical and relies on the principles of electrostatic dust collectors known in other industries. An estimative equation is deduced in order to quantify the electrical charge required to obtain the desired filtration. Although the device still needs more theoretical and experimental work, it could one day be used as a means of increasing the safety of airplanes passing trough an aerosol laden mass of air.

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

Science.gov (United States)

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

2012-01-01

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

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

Directory of Open Access Journals (Sweden)

M. Bezek

2013-03-01

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

ALPHA - The long-term passive decay heat removal and aerosol retention program

International Nuclear Information System (INIS)

Guentay, S.; Varadi, G.; Dreier, J.

1996-01-01

The Paul Scherrer Institute initiated the major new experimental and analytical program ALPHA in 1990. The program is aimed at understanding the long-term decay heat removal and aerosol questions for the next generation of Passive Light Water Reactors. The ALPHA project currently includes four major items: the large-scale, integral system behaviour test facility PANDA, which will be used to examine multidimensional effects of the SBWR decay heat removal system; an investigation of the thermal hydraulics of natural convection and mixing in pools and large volumes (LINX); a separate-effects study of aerosols transport and deposition in plenum and tubes (AIDA); while finally, data from the PANDA facility and supporting separate effects tests will be used to develop and qualify models and provide validation of relevant system codes. The paper briefly reviews the above four topics and current status of the experimental facilities. (author). 3 refs, 12 figs

ALPHA - The long-term passive decay heat removal and aerosol retention program

Energy Technology Data Exchange (ETDEWEB)

Guentay, S; Varadi, G; Dreier, J [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1996-12-01

The Paul Scherrer Institute initiated the major new experimental and analytical program ALPHA in 1990. The program is aimed at understanding the long-term decay heat removal and aerosol questions for the next generation of Passive Light Water Reactors. The ALPHA project currently includes four major items: the large-scale, integral system behaviour test facility PANDA, which will be used to examine multidimensional effects of the SBWR decay heat removal system; an investigation of the thermal hydraulics of natural convection and mixing in pools and large volumes (LINX); a separate-effects study of aerosols transport and deposition in plenum and tubes (AIDA); while finally, data from the PANDA facility and supporting separate effects tests will be used to develop and qualify models and provide validation of relevant system codes. The paper briefly reviews the above four topics and current status of the experimental facilities. (author). 3 refs, 12 figs.

The impact of aerosolized mucolytic agents on the airflow resistance of bacterial filters used in mechanical ventilation

Directory of Open Access Journals (Sweden)

Han-Chung Hu

2015-08-01

Conclusion: This study demonstrated the aerosolized mucolytic agents could increase the pressure drop of the bacterial filters during mechanical ventilation. The pressure drop of the bacterial filters was higher with 10% acetylcysteine. It is critical to continuously monitor the expiration resistance, auto-positive end-expiratory pressure, and ventilator output waveform when aerosolized 10% acetylcysteine was used in mechanical ventilation patients.

A new look at the economic disposal of contaminated aerosol filters

International Nuclear Information System (INIS)

Sinhuber, D.; Stiehl, H.H.; Schroth, W.

1977-01-01

HEPA filter elements loaded with radioactive aerosols represent a large percentage of the radioactive waste of nuclear plants. The HEPA filter elements used at present in air filter units are not suitable to an economic disposal and space-saving final storage on account of their construction. New concepts for HEPA filters are necessary from the point of view of waste disposal. The criteria of these new designs are as follows: reduction of space required for HEPA filters used at the same or even increased flow rates and with the same efficiency; essentially smaller dimensions of HEPA filters for storage in waste containers; removal without contamination, volume reduction (without contamination) for disposal of the HEPA filters; smallest possible volume of the HEPA filters after processing for final storage. The construction of HEPA filters as a result of the requirements mentioned above and taking into consideration the present stage of technology is explained. The advantages of such construction with regard to the criteria mentioned before are presented in comparison with the HEPA filters at present in use

Use of x-ray scattering in absorption corrections for x-ray fluorescence analysis of aerosol loaded filters

International Nuclear Information System (INIS)

Nielson, K.K.; Garcia, S.R.

1976-09-01

Two methods are described for computing multielement x-ray absorption corrections for aerosol samples collected in IPC-1478 and Whatman 41 filters. The first relies on scatter peak intensities and scattering cross sections to estimate the mass of light elements (Z less than 14) in the sample. This mass is used with the measured heavy element (Z greater than or equal to 14) masses to iteratively compute sample absorption corrections. The second method utilizes a linear function of ln(μ) vs ln(E) determined from the scatter peak ratios and estimates sample mass from the scatter peak intensities. Both methods assume a homogeneous depth distribution of aerosol in a fraction of the front of the filters, and the assumption is evaluated with respect to an exponential aerosol depth distribution. Penetration depths for various real, synthethic and liquid aerosols were measured. Aerosol penetration appeared constant over a 1.1 mg/cm 2 range of sample loading for IPC filters, while absorption corrections for Si and S varied by a factor of two over the same loading range. Corrections computed by the two methods were compared with measured absorption corrections and with atomic absorption analyses of the same samples

Evaluation of personal inhalable aerosol samplers with different filters for use during anthrax responses.

Science.gov (United States)

Grinshpun, Sergey A; Weber, Angela M; Yermakov, Michael; Indugula, Reshmi; Elmashae, Yousef; Reponen, Tiina; Rose, Laura

2017-08-01

Risk of inhalation exposure to viable Bacillus anthracis (B. anthracis) spores has primarily been assessed using short-term, stationary sampling methods which may not accurately characterize the concentration of inhalable-sized spores reaching a person's breathing zone. While a variety of aerosol sampling methods have been utilized during previous anthrax responses, no consensus has yet been established for personal air sampling. The goal of this study was to determine the best sampler-filter combination(s) for the collection and extraction of B. anthracis spores. The study was designed to (1) evaluate the performance of four filter types (one mixed cellulose ester, MCE (pore size = 3 µm), two polytetrafluoroethylene, PTFE (1 and 3 µm), and one polycarbonate, PC (3 µm)); and (2) evaluate the best performing filters in two commercially available inhalable aerosol samplers (IOM and Button). Bacillus thuringiensis kurstaki [Bt(k)], a simulant for B. anthracis, served as the aerosol challenge. The filters were assessed based on criteria such as ability to maintain low pressure drop over an extended sampling period, filter integrity under various environmental conditions, spore collection and extraction efficiencies, ease of loading and unloading the filters into the samplers, cost, and availability. Three of the four tested collection filters-except MCE-were found suitable for efficient collection and recovery of Bt(k) spores sampled from dry and humid as well as dusty and clean air environments for up to 8 hr. The PC (3 µm) filter was identified as the best performing filter in this study. The PTFE (3 µm) demonstrated a comparable performance, but it is more expensive. Slightly higher concentrations were measured with the IOM inhalable sampler which is the preferred sampler's performance criterion when detecting a highly pathogenic agent with no established "safe" inhalation exposure level. Additional studies are needed to address the effects of

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

The self-scattering of alpha-active substances has long been recognized and is attributed to expulsion of aggregates of atoms from the surface of alpha-active materials by alpha emission recoil energy, and perhaps to further propulsion of these aggregates by subsequent alpha recoils. Workers at the University of Lowell recently predicted that this phenomenon might affect the retention of alpha-active particulate matter by HEPA filters, and found support in experiments with 212 Pb. Tests at Oak Ridge National Laboratory have confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter media, such as that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.9 percent quoted for ordinary particulate matter were observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers by subsequent alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow

Liquid aerosol filtration by fibrous filters in interception and inertial regimes; Filtration des aerosols liquides par les filtres a fibres en regimes d`interception et d`inertie

Energy Technology Data Exchange (ETDEWEB)

Gougeon, R

1994-09-26

In most previous studies of aerosol filtration, attention is focused on the maximum penetrating particle size region where the predominant mechanisms for collection are brownian diffusion and interception. In contrary the inertial regime remains poorly understood. Therefore, the aim of this study was to improve understanding of the behaviour of fibrous filters with liquid aerosols ar high frontal velocities both in the stationary and nonstationary filtration. Stationary filtration is first investigated. Experiments are done with special filters called `formettes` which have well defined structural characteristics. Precise results obtained with those filters allow us to select two relations quoted in the literature in order to describe the diffusion and the interception and to determine an empirical correlation describing the inertial impaction. Then this correlation with an industrial filter. In the second part, the evolution of the performances of fibrous filters loaded with liquid aerosols is studied experimentally and theoretically. We show that, in the inertial regime the filter efficiency first decreases and then increases rapidly with the loading rate. This increase is particularly important at high frontal velocities and with big particles. Macroscopic observations of high loaded filters show that the liquid is located in the fibre`s intersections to form big flat surfaces. A tentative of describing the evolution of the filter efficiency in modifying our stationary filtration model in order to take into account those liquid surfaces in the filter gives encouraging results. (authors). 92 refs., 93 figs., 11 tabs., 4 appends.

Microwave-assisted extraction of metal elements from glass fibrous filters for aerosol sampling

International Nuclear Information System (INIS)

Li Dong-Mei; Zhang Li-Xing; Wang Xu-Hui; Liu Long-Bo

2003-01-01

Atmospheric aerosols are generally collected on filters according to the International Monitoring System (IMS) designed in the Comprehensive Nuclear-Test-Ban Treaty (CTBT). More information could be revealed when the filter sample is pretreated rather than measured directly by γ-ray spectrometer. Microwave-assisted extraction (MAE) is a suitable method that gives higher recoveries of elements from glass fibrous filters under different conditions. The results indicate that the MAE is a highly efficient and robust method for the treatment of glass fibrous filter samples. The recoveries of potential fission products from glass fibrous filter samples by microwave-assisted extraction meet the efficiency of the extraction by both aqua regia and 2% HCl. (author)

Optimal Performance Simulation of a Metal Fiber Filter for Capturing Radioactive Aerosols

International Nuclear Information System (INIS)

Lee, Seung Uk; Lee, Chan Hyun; Park, Min Chan; Lee, Jaek Eun

2016-01-01

In this study, the metal fiber filter used for removing radioactive aerosol is systematically dissected and studied in order to figure out the optimal design which can be applied to the actual operation conditions in nuclear heating, ventilation and air conditioning (HVAC) systems for particle collection. In order to derive the optimal design for metal fiber HEPA filter, a numerical model is developed and its results are compared to experimental data to test reliability. Moreover, sensitivity analysis is performed using important parameters to determine which parameters have large influence on the filter performance. Using the model developed in this study, optimal design parameters for pleated metal fiber filters are derived which include fiber diameter less than 4 μm, solidity larger than 0.2, filter thickness larger than 1 mm, and face velocity lower than 5 cm/s. With these conditions, the metal filter qualified for the HEPA filter standard which specified 99.97% efficiency in the 0.3 μm particle size range.

Study on the Metal Fiber Filter Modeling for Capturing Radioactive Aerosol

Energy Technology Data Exchange (ETDEWEB)

Lee, Seunguk; Lee, Chanhyun; Park, Minchan; Lee, Jaekeun [EcoEnergy Research Institute, Busan (Korea, Republic of)

2015-05-15

The components of air cleaning system are demisters to remove entrained moisture, pre-filters to remove the bulk of the particulate matter, high efficiency particulate air (HEPA) filters, iodine absorbers(generally, activated carbon) and HEPA filters after the absorbers for redundancy and collection of carbon fines. The HEPA filters are most important components to prevent radioactive aerosols from being released to control room and adjacent environment. The Conventional HEPA filter has pleated media for low pressure drop. Consequently, the filters must provide high collection efficiency as well as low pressure drop. Unfortunately, conventional HEPA filters are made of glass fiber and polyester, and pose disposal issues since they cannot be recycled. In fact, 31,055 HEPA filters used in nuclear facilities in the U.S are annually disposed. The Analyses at face velocities 1cm/s and 10cm/s are also carried out, and they also show R2 value of 0.995. However, since official HEPA filter standards are established at face velocity of 5cm/s, this value will be used in further analysis. From the comparative studies carried out at different filter thickness and face velocities, a good correlation is found between the model and the experiment.

Nano size Aerosols of Radon Decay Products in Various Environments

International Nuclear Information System (INIS)

Vaupotic, J.

2008-01-01

The radioactive noble gas radon (222Rn, alpha decay, t 1/2 = 3.82 days) is always accompanied by its short-lived decay products (RnDP): 218Po (alpha decay, t 1/2 = 3.10 min), 214Pb (beta/gamma decay, t 1/2 = 26.8 min), 214Bi (beta/gamma decay, t 1/2 = 19.9 min), and 214Po (alpha decay, t 1/2 = 164 μs). In indoor and outdoor air, they appear as unattached RnDP in the form of clusters in the size range 0.5-3 nm and as attached RnDP between 200 and 800 nm. Because of plate-out of aerosols on the walls and floor of a room, as well as air movement and entry of fresh air, radioactive equilibrium between RnDP and Rn in indoor air is only partly achieved and is expressed as a fraction between 0 and 1, called the equilibrium factor, F. Birchall and James elaborated a dosimetric approach to calculate the dose conversion factor, DCF D , based on f un . In this paper, the results of our studies on fun in 29 rooms of kindergartens and 26 rooms of elementary and high schools, at the lowest point and the railway station in the Postojna Cave, and in 4 rooms in wineries in Slovenia are reported, and DCF D values based on the Porstendorfer formulae are discussed and compared with the DCF E value recommended by ICRP-65

United role of radon decay products and nano-aerosols in radon dosimetry

Science.gov (United States)

Smerajec, M.; Vaupotič, J.

2012-04-01

The major part of human exposure to natural radiation originates from inhalation of radon (Rn) and radon short-lived decay products (RnDP: 218Po, 214Pb, 214Bi and 214Po). RnDP are formed as a result of α-transformation of radon. In the beginning they are positive ions which neutralize and form clusters with air molecules, and later partly attach to background aerosol particles in indoor air. Eventually, they appear as radioactive nano-aerosols with a bimodal size distribution in ranges of 1-10 nm (unattached RnDP) and of 200-800 nm (attached RnDP). When inhaled, they are deposited in the respiratory tract. Deposition is more efficient for smaller particles. Therefore, the fraction (fun) of the unattached RnDP, which appears to be influenced by the number concentration and size distribution of general (background) aerosols in the ambient air, has a crucial role in radon dosimetry. Radon, radon decay products and general aerosols have been monitored simultaneously in the kitchen of a typical rural house under real living conditions, also comprising four human activities generating particular matter: cooking and baking, as two typical activities in kitchen, and cigarette smoking and candle burning. In periods without any human activity, the total number concentration of general aerosol ranged from 1000 to 3000 cm-3,with the geometric mean of particle diameter in the range of 60-68 nm and with 0.1-1 % of particles smaller than 10 nm. Preparation of coffee changed the concentration to 193,000 cm-3, the geometric mean of diameter to 20 nm and fraction of particles smaller than 10 nm to 11 %. The respective changes were for baking cake: 503,000 cm-3, 17 nm and 19 %, for smoking:423,000 cm-3, 83 nm and 0.4 %, and forcandle burning: 945,000 cm-3, 8 nm and 85 %. While, as expected, a reduction of fun was observed during cooking, baking and smoking, when larger particles were emitted, fun did not increase during candle burning with mostly particles smaller than 10 nm

Multiple HEPA filter test methods, July 1, 1974--March 31, 1975

International Nuclear Information System (INIS)

Schuster, B.G.; Osetek, D.J.

1975-08-01

A laboratory apparatus has been constructed for testing two HEPA filters in a series configuration. The apparatus consists of an instrumented wind tunnel in which the HEPA filters are mounted, and an auxiliary wind tunnel for obtaining diluted samples of the challenge aerosol upstream of the first filter. Measurements performed with a single particle aerosol spectrometer demonstrate the capability for measuring overall protection factors of greater than 2.5 x 10 8 . The decay of penetration as a function of time in individual HEPA filters indicates no preferential size discrimination in the range of 0.1 μm to 1.0 μm; nor is there a preferential size discrimination of penetration in this same range. A theoretical feasibility study has been performed on the use of an inhomogeneous electric field/induced aerosol electric dipole interaction for potential use as an air cleaning mechanism. Numerical evaluation of a coaxial cylinder geometry indicates that the method is feasible for collection of particles down to 0.1 μm under typical airflow velocity conditions. Small modifications in the geometry may be incorporated to create an instrument capable of measuring particle size. Geometries other than coaxial cylinders are also under investigation

In-duct countermeasures for reducing fire-generated-smoke-aerosol exposure to HEPA filters

International Nuclear Information System (INIS)

Alvares, N.J.; Beason, D.G.; Ford, H.W.

1978-01-01

An experimental program was conducted to assess the endurance and lifetime of HEPA filters exposed to fire-generated aerosols, and to reduce the aerosol exposure by installing engineering countermeasures in the duct between the fire source and HEPA filters. Large cribs of wood and other potential fuels of interest were ''forcefully burned'' in a partially ventilated enclosure. In a ''forceful burn'' the crib of fuel is continuously exposed to an energetic premixed methane flame during the entire experimental period. This tactic serves two purposes: it optimizes the production of smoke rich in unburned pyrolyzates which provides severe exposure to the filters, and it facilitates the ignition and enhances the combustion of cribs formed with synthetic polymers. The experiments were conducted in an enclosure specifically designed and instrumented for fire tests. The test cell has a volume of 100 m 3 and includes instrumentation to measure the internal temperature distribution, pressure, thermal radiation field, flow fields, gas concentration, particulate size distribution and mass, fuel weight loss, inlet and exit air velocities, and smoke optical density. The countermeasure techniques include the use of passively operated sprinkler systems in the fire test cell, of fine and dense water scrubbing sprays, and of rolling prefiltration systems in the exit duct of the fire test cell. Of the countermeasures surveyed, the rolling prefilter system showed the most promise. This paper concentrates on the effect of control variables; i.e., enclosure air supply, fuel composition and crib porosity on the combustion response; i.e., crib burning rate, enclosure temperature rise, oxygen consumption, and CO, CO 2 and total hydrocarbon production. A discussion of the attempts to rationalize smoke aerosol properties will be included along with results from the effect of countermeasure application on HEPA filter lifetimes

Test equipment used for radiation protection type testing of aerosol filters at the National Board of Nuclear Safety and Radiation Protection (SAAS)

International Nuclear Information System (INIS)

Ullmann, W.; Przyborowski, S.

1977-01-01

Following a description of the overall design of test equipment developed in the SAAS for radiation protection type testing of aerosol filters, the most important physical and technical details concerning the preparation and measurement of test aerosols as well as the sampling procedure upstream and downstream of the filter to the tested, are comprehensively discussed. Furthermore, experiences gained during several years with different devices for mixing and diluting the aerosols are reported. (author)

Method of monitoring volume activity of natural radioactive aerosol

International Nuclear Information System (INIS)

Dvorak, V.

1980-01-01

The method of monitoring radioactivity of a aerosol trapped, eg., with a filter is based on counting quasi-coincidences of the RaC-RaC' and ThC-ThC' decay. The first electronic unit counts quasi-coincidences at a time interval proportional to the ThC' half-life while the second electronic unit counts quasi-coincidences at a time interval proportional to the RaC' half-life, reduced by the time interval of the first electronic unit. The quasi-coincidences are evaluated of the RaC-RaC' decay independently of the ThC-ThC' quasi-coincidences and the decay products of the trapped radon and thoron gases are thus offset separately. (J.P.)

Device for automatic filter changing. Einrichtung zum selbsttaetigen Wechseln eines Filters

Energy Technology Data Exchange (ETDEWEB)

Matschoss, V; Naschwitz, A; Wild, H

1984-01-05

A filter is moved from a store to an aerosol pipe by a lifting device and is clamped there. At the end of the operating period, the lifting device moves a new filter to a parking place. Control is from limit switches of the lifting, clamping and thrust devices and the position control of the store is by the limit switches. The filter changing device is enclosed in a gastight case, prevents blockage of a filter and makes it possible to set a certain operating period, to change the filter without interrupting the aerosol flow and to measure each filter in the sequence of operation outside the aerosol flow.

Size-Resolved Penetration Through High-Efficiency Filter Media Typically Used for Aerosol Sampling

Czech Academy of Sciences Publication Activity Database

Zíková, Naděžda; Ondráček, Jakub; Ždímal, Vladimír

2015-01-01

Roč. 49, č. 4 (2015), s. 239-249 ISSN 0278-6826 R&D Projects: GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:67985858 Keywords : filters * size-resolved penetration * atmospheric aerosol sampling Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.953, year: 2015

Activity size distributions for long-lived radon decay products in aerosols collected in Barcelona (Spain)

International Nuclear Information System (INIS)

Camacho, A.; Valles, I.; Vargas, A.; Gonzalez-Perosanz, M.; Ortega, X.

2009-01-01

The activity median aerodynamic diameters (AMADs) of long-lived radon decay product ( 210 Pb, 210 Po) in aerosols collected in the Barcelona area (Northeast Spain) during the period from April 2006 to February 2008 are presented. The 210 Po mean AMAD was 420 nm, while the 210 Pb mean AMAD was 500 nm. The temporal evolution of 210 Pb and 210 Po AMADs shows maxima in autumn and winter and minima in spring and summer. 210 Pb AMAD are being used to estimate the mean-residence time of atmospheric aerosols.

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.)

Study of the stopping power of various filters; Etude du pouvoir d'arret de differents filtres

Energy Technology Data Exchange (ETDEWEB)

Madelaine, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The first part is devoted to a study of aerosols obtained from the combustion of various smoke-producing compounds. A trial aerosol of which the size distribution is the closest possible to that of atmospheric dusts has been defined. The efficiency of various filters has been determined for successive increments of the dimensions and not for the whole range of its diameter distribution. The variation in the efficiency of the filtering layers as a function of the filtering speed and particle size has been studied for aerosols having particle diameters of over 0.3 {mu}. The second part describes an original method for measuring the efficiency of filters for ultra-fine particles (under 0.1 {mu}) using the fixation properties of radioactive atoms resulting from the decay of thoron. (author) [French] La premiere partie est consacree a l'etude des aerosols obtenus a partir de la combustion de divers types de fumigenes. Un aerosol d'essai, dont la repartition granulometrique se rapproche le plus possible des poussieres atmospheriques a ete defini. L'efficacite de plusieurs filtres a ete determinee pour des tranches successives de dimension et non pour l'aerosol pris dans sa totalite. La variation de l'efficacite des couches filtrantes en fonction de la taille des particules et de la vitesse de filtration a ete examinee pour des aerosols superieurs a 0,3 {mu}. La seconde partie decrit une methode originale permettant de mesurer l'efficacite des filtres pour des particules ultrafines (inferieures a 0,1 {mu}) en utilisant la propriete de fixation des atomes radioactifs des descendants du thoron. (auteur)

Study of different filters

International Nuclear Information System (INIS)

Cochinal, R.; Rouby, R.

1959-01-01

This note first contains a terminology related to filters and to their operation, and then proposes an overview of general characteristics of filters such as load loss with respect to gas rate, efficiency, and clogging with respect to filter pollution. It also indicates standard aerosols which are generally used, how they are dosed, and how efficiency is determined with a standard aerosol. Then, after a presentation of the filtration principle, this note reports the study of several filters: glass wool, filter papers provided by different companies, Teflon foam, English filters, Teflon wool, sintered Teflonite, quartz wool, polyvinyl chloride foam, synthetic filter, sintered bronze. The third part reports the study of some aerosol and dust separators

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).

The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

DEFF Research Database (Denmark)

Fadeyi, M.O.; Weschler, Charles J.; Tham, K.W.

2009-01-01

This study examined the impact of recirculation rates (7 and 14 h(-1)), ventilation rates (1 and 2 h(-1)), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling......, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35...

Automated high-volume aerosol sampling station for environmental radiation monitoring

International Nuclear Information System (INIS)

Toivonen, H.; Honkamaa, T.; Ilander, T.; Leppaenen, A.; Nikkinen, M.; Poellaenen, R.; Ylaetalo, S.

1998-07-01

An automated high-volume aerosol sampling station, known as CINDERELLA.STUK, for environmental radiation monitoring has been developed by the Radiation and Nuclear Safety Authority (STUK), Finland. The sample is collected on a glass fibre filter (attached into a cassette), the airflow through the filter is 800 m 3 /h at maximum. During the sampling, the filter is continuously monitored with Na(I) scintillation detectors. After the sampling, the large filter is automatically cut into 15 pieces that form a small sample and after ageing, the pile of filter pieces is moved onto an HPGe detector. These actions are performed automatically by a robot. The system is operated at a duty cycle of 1 d sampling, 1 d decay and 1 d counting. Minimum detectable concentrations of radionuclides in air are typically 1Ae10 x 10 -6 Bq/m 3 . The station is equipped with various sensors to reveal unauthorized admittance. These sensors can be monitored remotely in real time via Internet or telephone lines. The processes and operation of the station are monitored and partly controlled by computer. The present approach fulfils the requirements of CTBTO for aerosol monitoring. The concept suits well for nuclear material safeguards, too

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.

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

Optical transmission through aerosol deposits on diffusely reflective filters: a method for measuring the absorbing component of aerosol particles

International Nuclear Information System (INIS)

Rosen, H.; Novakov, T.

1983-01-01

It is unclear why the backscattered radiation from nonabsorbing particles should not make a significant contribution to the optical attenuation measurement. This is especially true where the absorbing component represents only a very small fraction of the aerosol mass. In this Letter we present a simple theoretical model which accounts for all these observations and points out the critical role of the filter substrate as an almost perfect diffuse reflector in the technique

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

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

Estimation of the upper limit of aerosol nanoparticles penetration through inhomogeneous fibrous filters

International Nuclear Information System (INIS)

Podgorski, Albert

2009-01-01

The fully segregated flow model (FSFM) was formulated to describe filtration of aerosol nanoparticles in polydisperse fibrous filters made of fibers with different diameters. The model is capable of predicting significantly higher penetration of nanoparticles through polydisperse filters than it may be expected from the classical theory applied to a mean fiber diameter. The model was solved numerically in the case of the log-normal fiber size distribution, and a simple correlation between the actual penetration through a polydisperse filter and the one calculated for the geometric mean fiber diameter was proposed. Equivalent fiber diameter for deposition due to Brownian diffusion was determined and it was found to be dependent on particle size and filter's polydispersity degree, being significantly greater than any mean fiber diameter. It was noted that it is impossible to select any one universal mean fiber diameter to describe penetration of nanoparticles with different sizes. It was also shown that in the case of a polydisperse fibrous filter the apparent exponent of the Peclet number based on the mean fiber diameter is greater than the expected value of -2/3 for diffusional deposition in a monodisperse filter. This prediction is in agreement with the available experimental data. The FSFM is expected to give the estimation of the upper limit of nanoparticles penetration in polydisperse fibrous filters.

Diurnal and seasonal variations of concentration and size distribution of nano aerosols (10-1100 nm) enclosing radon decay products in the Postojna Cave, Slovenia

International Nuclear Information System (INIS)

Bezek, M.; Gregoric, A.; Kavasi, N.; Vaupotic, J.

2012-01-01

At the lowest point along the tourist route in the Postojna Cave, the activity concentration of radon ( 222 Rn) short-lived decay products and number concentration and size distribution of background aerosol particles in the size range of 10-1100 nm were measured. In the warm yearly season, aerosol concentration was low (52 cm -3 ) with 21 % particles smaller than 50 nm, while in the cold season, it was higher (1238 cm -3 ) with 8 % of -3 , and fractions of unattached radon decay products were 0.62 and 0.13, respectively. (authors)

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

On-site test of filters in nuclear facilities using radioactive sodium chloride (24Na)-aerosol and methyl iodide (131I)

International Nuclear Information System (INIS)

Heidam, N.Z.; Hansen, K.A.; Fenger, J.; Flyger, H.; Hedemann Jensen, P.

1986-02-01

The nuclar facilities at Risoe National Laboratory are equipped with high-efficiency filters to protect the environment from routine or accidental releases of radioactive material. The filter efficiency must be tested regularly and a method for on-site control is described. It is based on injection of a radioactive sample in the filter duct, followed by sampling before and after the filter. HEPA-filters are tested with a 24 NaCl-aerosol and charcoal filters with 131 ICH 3 . Normally samples of 1 mCi are used. Penetrations (1 - efficiency) can be determined with a relative uncertainty of 10-15%. (author)

Evaluating the Sensitivity of the Mass-Based Particle Removal Calculations for HVAC Filters in ISO 16890 to Assumptions for Aerosol Distributions

Directory of Open Access Journals (Sweden)

Brent Stephens

2018-02-01

Full Text Available High efficiency particle air filters are increasingly being recommended for use in heating, ventilating, and air-conditioning (HVAC systems to improve indoor air quality (IAQ. ISO Standard 16890-2016 provides a methodology for approximating mass-based particle removal efficiencies for PM1, PM2.5, and PM10 using size-resolved removal efficiency measurements for 0.3 µm to 10 µm particles. Two historical volume distribution functions for ambient aerosol distributions are assumed to represent ambient air in urban and rural areas globally. The goals of this work are to: (i review the ambient aerosol distributions used in ISO 16890, (ii evaluate the sensitivity of the mass-based removal efficiency calculation procedures described in ISO 16890 to various assumptions that are related to indoor and outdoor aerosol distributions, and (iii recommend several modifications to the standard that can yield more realistic estimates of mass-based removal efficiencies for HVAC filters, and thus provide a more realistic representation of a greater number of building scenarios. The results demonstrate that knowing the PM mass removal efficiency estimated using ISO 16890 is not sufficient to predict the PM mass removal efficiency in all of the environments in which the filter might be used. The main reason for this insufficiency is that the assumptions for aerosol number and volume distributions can substantially impact the results, albeit with some exceptions.

Development of a double-layered ceramic filter for aerosol filtration at high-temperatures: the filter collection efficiency.

Science.gov (United States)

de Freitas, Normanda L; Gonçalves, José A S; Innocentini, Murilo D M; Coury, José R

2006-08-25

The performance of double-layered ceramic filters for aerosol filtration at high temperatures was evaluated in this work. The filtering structure was composed of two layers: a thin granular membrane deposited on a reticulate ceramic support of high porosity. The goal was to minimize the high pressure drop inherent of granular structures, without decreasing their high collection efficiency for small particles. The reticulate support was developed using the technique of ceramic replication of polyurethane foam substrates of 45 and 75 pores per inch (ppi). The filtering membrane was prepared by depositing a thin layer of granular alumina-clay paste on one face of the support. Filters had their permeability and fractional collection efficiency analyzed for filtration of an airborne suspension of phosphatic rock in temperatures ranging from ambient to 700 degrees C. Results revealed that collection efficiency decreased with gas temperature and was enhanced with filtration time. Also, the support layer influenced the collection efficiency: the 75 ppi support was more effective than the 45 ppi. Particle collection efficiency dropped considerably for particles below 2 microm in diameter. The maximum collection occurred for particle diameters of approximately 3 microm, and decreased again for diameters between 4 and 8 microm. Such trend was successfully represented by the proposed correlation, which is based on the classical mechanisms acting on particle collection. Inertial impaction seems to be the predominant collection mechanism, with particle bouncing/re-entrainment acting as detachment mechanisms.

Diurnal and seasonal variations of concentration and size distribution of nano aerosols (10-1100 nm) enclosing radon decay products in the Postojna Cave, Slovenia.

Science.gov (United States)

Bezek, M; Gregoric, A; Kávási, N; Vaupotic, J

2012-11-01

At the lowest point along the tourist route in the Postojna Cave, the activity concentration of radon ((222)Rn) short-lived decay products and number concentration and size distribution of background aerosol particles in the size range of 10-1100 nm were measured. In the warm yearly season, aerosol concentration was low (52 cm(-3)) with 21 % particles smaller than 50 nm, while in the cold season, it was higher (1238 cm(-3)) with 8 % of <50 nm particles. Radon activity concentrations were 4489 and 1108 Bq m(-3), and fractions of unattached radon decay products were 0.62 and 0.13, respectively.

Analysis of low-pass filters for approximate deconvolution closure modelling in one-dimensional decaying Burgers turbulence

Science.gov (United States)

San, O.

2016-01-01

The idea of spatial filtering is central in approximate deconvolution large-eddy simulation (AD-LES) of turbulent flows. The need for low-pass filters naturally arises in the approximate deconvolution approach which is based solely on mathematical approximations by employing repeated filtering operators. Two families of low-pass spatial filters are studied in this paper: the Butterworth filters and the Padé filters. With a selection of various filtering parameters, variants of the AD-LES are systematically applied to the decaying Burgers turbulence problem, which is a standard prototype for more complex turbulent flows. Comparing with the direct numerical simulations, it is shown that all forms of the AD-LES approaches predict significantly better results than the under-resolved simulations at the same grid resolution. However, the results highly depend on the selection of the filtering procedure and the filter design. It is concluded that a complete attenuation for the smallest scales is crucial to prevent energy accumulation at the grid cut-off.

Comparison of testing methods for particulate filters

International Nuclear Information System (INIS)

Ullmann, W.; Przyborowski, S.

1983-01-01

Four testing methods for particulate filters were compared by using the test rigs of the National Board of Nuclear Safety and Radiation Protection: 1) Measurement of filter penetration P as a function of particle size d by using a polydisperse NaC1 test aerosol and a scintillation particle counter; 2) Modified sodium flame test for measurement of total filter penetration P for various polydisperse NaC1 test aerosols; 3) Measurement of total filter penetration P for a polydisperse NaC1 test aerosol labelled with short-lived radon daughter products; 4) Measurement of total filter penetration P for a special paraffin oil test aerosol (oil fog test used in FRG according DIN 24 184, test aerosol A). The investigations were carried out on sheets of glass fibre paper (five grades of paper). Detailed information about the four testing methods and the used particle size distributions is given. The different results of the various methods are the base for the discussion of the most important parameters which influence the filter penetration P. The course of the function P=f(d) shows the great influence of the particle size. As expected there was also found a great dependence both from the test aerosol as well as from the principle and the measuring range of the aerosol-measuring device. The differences between the results of the various test methods are greater the lower the penetration. The use of NaCl test aerosol with various particle size distributions gives great differences for the respective penetration values. On the basis of these results and the values given by Dorman conclusions are made about the investigation of particulate filters both for the determination of filter penetration P as well as for the leak test of installed filters

Offline estimation of decay time for an optical cavity with a low pass filter cavity model.

Science.gov (United States)

Kallapur, Abhijit G; Boyson, Toby K; Petersen, Ian R; Harb, Charles C

2012-08-01

This Letter presents offline estimation results for the decay-time constant for an experimental Fabry-Perot optical cavity for cavity ring-down spectroscopy (CRDS). The cavity dynamics are modeled in terms of a low pass filter (LPF) with unity DC gain. This model is used by an extended Kalman filter (EKF) along with the recorded light intensity at the output of the cavity in order to estimate the decay-time constant. The estimation results using the LPF cavity model are compared to those obtained using the quadrature model for the cavity presented in previous work by Kallapur et al. The estimation process derived using the LPF model comprises two states as opposed to three states in the quadrature model. When considering the EKF, this means propagating two states and a (2×2) covariance matrix using the LPF model, as opposed to propagating three states and a (3×3) covariance matrix using the quadrature model. This gives the former model a computational advantage over the latter and leads to faster execution times for the corresponding EKF. It is shown in this Letter that the LPF model for the cavity with two filter states is computationally more efficient, converges faster, and is hence a more suitable method than the three-state quadrature model presented in previous work for real-time estimation of the decay-time constant for the cavity.

Aerosol-phase activity of iodine captured from a triiodide resin filter on fine particles containing an infectious virus.

Science.gov (United States)

Heimbuch, B K; Harnish, D A; Balzli, C; Lumley, A; Kinney, K; Wander, J D

2015-06-01

To avoid interference by water-iodine disinfection chemistry and measure directly the effect of iodine, captured from a triiodide complex bound to a filter medium, on viability of penetrating viral particles. Aerosols of MS2 coli phage were passed through control P100 or iodinated High-Efficiency Particulate Air media, collected in plastic bags, incubated for 0-10 min, collected in an impinger containing thiosulphate to consume all unreacted iodine, plated and enumerated. Comparison of viable counts demonstrated antimicrobial activity with an apparent half-life for devitalization in tens of seconds; rate of kill decreased at low humidity and free iodine was captured by the bags. The results support the mechanism of near-contact capture earlier proposed; however, the disinfection chemistry in the aerosol phase is very slow on the time scale of inhalation. This study shows that disinfection by filter-bound iodine in the aerosol phase is too slow to be clinically significant in individual respiratory protection, but that it might be of benefit to limit airborne transmission of infections in enclosed areas. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Photoacoustic and filter measurements related to aerosol light absorption during the Northern Front Range Air Quality Study (Colorado 1996/1997)

Science.gov (United States)

Moosmüller, H.; Arnott, W. P.; Rogers, C. F.; Chow, J. C.; Frazier, C. A.; Sherman, L. E.; Dietrich, D. L.

1998-11-01

A new photoacoustic instrument for the measurement of aerosol light absorption was collocated with conventional aerosol instrumentation during the 1996-1997 winter intensive monitoring period of the Northern Front Range Air Quality Study. Measurements of the light absorption efficiency for black carbon were 5 m2/g at 685 nm and 10 m2/g at 532 nm, and for elemental carbon, they were 3.6 m2/g at 685 nm. We show that these values together with previous photoacoustic measurements of aerosol light absorption shed some light on the wavelength dependence of absorption efficiency for carbonaceous aerosol in the visible and near-visible region. Integrating plate type filter measurements of aerosol light absorption result in far larger values than those measured with the photoacoustic instrument. We demonstrate that a recently published correction technique [Horvath, 1997] can yield improved agreement.

Study of different filters; Etude de differents filtres

Energy Technology Data Exchange (ETDEWEB)

Cochinal, R.; Rouby, R.

1959-07-01

This note first contains a terminology related to filters and to their operation, and then proposes an overview of general characteristics of filters such as load loss with respect to gas rate, efficiency, and clogging with respect to filter pollution. It also indicates standard aerosols which are generally used, how they are dosed, and how efficiency is determined with a standard aerosol. Then, after a presentation of the filtration principle, this note reports the study of several filters: glass wool, filter papers provided by different companies, Teflon foam, English filters, Teflon wool, sintered Teflonite, quartz wool, polyvinyl chloride foam, synthetic filter, sintered bronze. The third part reports the study of some aerosol and dust separators.

A mathematical model of aerosol holding chambers

DEFF Research Database (Denmark)

Zak, M; Madsen, J; Berg, E

1999-01-01

A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London...

Simulation of Rn-222 decay products concentration deposited on a filter. Description of radon1.pas computer program

International Nuclear Information System (INIS)

Machaj, B.

1996-01-01

A computer program allowing simulation of activity distribution of 222 Rn short lived decay products deposited on a filter against time is presented, for any radiation equilibrium degree of the decay products. Deposition of the decay products is simulated by summing discrete samples every 1/10 min in the sampling time from 1 to 10 min. The concentration (activity) of the decay products is computed in one minute intervals in the range 1 - 100 min. The alpha concentration and the total activity of 218 Po + 214 Po produced are computed in the range 1 to 100 min as well. (author). 10 refs, 4 figs

Development of α and/or β activity aerosol instrumentation

International Nuclear Information System (INIS)

Lu Zhengyong; Li Aiwu; Gou Quanlu

1996-01-01

A radioactive aerosol instrumentation is developed recently for measuring the α and/or β activity of artificial radioactivity aerosols which are produced in nuclear facilities. The instrumentation has the function discriminating natural radioactivity aerosols resulted from radon and thoron daughters, and it is enabled in time and without delay to measure α and β artificial activity collected with a filter by pumping aerosols through this filter. The energy discrimination and compensation method is used for eliminating the influence of natural αradioactivity aerosols. To minimize the influence of natural β-radioactivity aerosols, the method measuring the ratio α/β of natural aerosols is also used in the instrument. The improved methods eliminating the influence of natural background α and β aerosols are used so that both α and β artificial activities in aerosol filter samples can be monitored simultaneously. The instrumentation is appropriate for monitoring α and/or β artificial radioactive aerosols

Mitigation of radon and thoron decay products by filtration

International Nuclear Information System (INIS)

Wang Jin; Meisenberg, Oliver; Chen Yongheng; Karg, Erwin; Tschiersch, Jochen

2011-01-01

Inhalation of indoor radon ( 222 Rn) and thoron ( 220 Rn) decay products is the most important source of exposure to ionizing radiation for the human respiratory tract. Decreasing ventilation rates due to energy saving reasons in new buildings suggest additional active mitigation techniques to reduce the exposure in homes with high radon and thoron concentrations but poor ventilation. Filtration techniques with HEPA filters and simple surgical mask material have been tested for their potential to reduce the indoor exposure in terms of the total effective dose for mixed radon and thoron indoor atmospheres. The tests were performed inside an experimental room providing stable conditions. Filtration (at filtration rates of 0.2 h -1 and larger) removes attached radon and thoron decay products effectively but indoor aerosol as well. Therefore the concentration of unattached decay products (which have a higher dose coefficient) may increase. The decrease of the attached decay product concentrations could be theoretically described by a slowly decreasing exponential process. For attached radon decay products, it exhibited a faster but weaker removal process compared to attached thoron decay products (- 70% for attached radon decay products and - 80% for attached thoron decay products at a filtration rate of 0.5 h -1 with an HEPA filter). The concentration of unattached thoron decay products increased distinctly during the filtration process (+ 300%) while that of unattached radon decay products rose only slightly though at a much higher level (+ 17%). In the theoretical description these observed differences could be attributed to the different half-lives of the nuclides. Considering both effects, reduced attached and increased unattached decay product concentrations, filtration could significantly decrease the total effective dose from thoron whereas the overall effect on radon dose is small. A permanent filtration is recommended because of the slow decrease of the

Mosquito knock-down and adulticidal activities of essential oils by vaporizer, impregnated filter paper and aerosol methods

Directory of Open Access Journals (Sweden)

M. Ramar

2014-09-01

Full Text Available Essential oils from 12 medicinal plants were evaluated by three different bioassay methods (Vaporizer, Filter paper and Aerosol for Knock-down and adulticidal efficacy on the filarial vector mosquito, Culex quinquefasciatus. Based on screening results the effective plants were selected for investigating Knock-down and adulticidal potential against adult female of the laboratory-reared mosquito species, Cx. quinquefasciatus. In vaporizer bioassay method four different doses (1.25, 2.5, 5 and 10% were used. Four different doses (0.625, 1.25, 2.5 and 10% were used both filter paper (cm2 and aerosol (cm3 bioassay methods. Five essential oils (calamus, camphor, citronella, clove and eucalyptus were identified as potential treatments in vaporizer bioassay. The result showed that the knock down time decreased with increased concentration in clove oil treatment; the Knock-down time (KT 50 = 46.1 ± 0.1, 38.5 ± 0.1, 30.7 ± 0.2, and 20.1 ± 0.1 minutes was recorded at 1.25, 2.5, 5 and 10% /cm3 respectively. In filter paper method nine essential oils were identified as potential treatments. After 1 hr exposure period clove oil recorded the lowest median Knock-down time (KT50 which was calculated as 9.15 ± 0.1min/cm2. Followed by citronella (KT50 =11.4 ± 0.1 min and eucalyptus (KT50 =11.4 ±0.1min oils since they recorded lower median Knock-down time. All the twelve essential oils were identified as potential treatments in aerosol activity. The lethal time decreased when the concentration increased. At 5 % concentration the median lethal time (LT50 for clove oil was calculated as (LT50=3.80 ± 0.1minutes. The Cinnamon oil was effective which recorded (LT50 = 1.99 mins as median lethal time. Camphor (LT50 =19.6± 0.1 min oil were found to be less toxic by aerosol method. These results suggest that clove oil and cinnamon oil have the potential to be used as a eco-friendly approach for the control of the major important filaria vector Cx. quinquefasciatus

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

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

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

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.

KfK Laboratory for Aerosol Physics and Filter Technology. Progress report and development activities in 1990

International Nuclear Information System (INIS)

1991-03-01

The activities undertaken by the laboratory for aerosol physics and filter technology (LAF) in 1990 under the following projects are described: (1) nuclear safety research (safety and material problems of fast breeders, IWR-oriented safety research); (2) pollutant control in the environment (communal waste management, emission-reducing processes, climate research - pollutants' behaviour in the atmosphere), and (3) radioactive waste management (basic work on reprocessing technologies). The annex lists the publications by the LAF staff. (BBR) [de

Degradation of HEPA filters exposed to DMSO

International Nuclear Information System (INIS)

Bergman, W.; Wilson, K.; Larsen, G.; Lopez, R.; LeMay, J.

1994-01-01

Dimethyl sulfoxide (DMSO) sprays are being used to remove the high explosive (HE) from nuclear weapons in the process of their dismantlement. A boxed 50 cfm HEPA filter with an integral prefilter was exposed to DMSO vapor and aerosols that were generated by a spray nozzle to simulate conditions expected in the HE dissolution operation. After 198 hours of operation, the pressure drop of the filter had increased from 1.15 inches to 2.85 inches, and the efficiency for 0.3 μm dioctyl sebacate (DOS) aerosols decreased from 99.992% to 98.6%. Most of the DMSO aerosols had collected as a liquid pool inside the boxed HEPA. The liquid was blown out of the filter exit with 100 cfm air flow at the end of the test. Since the filter still met the minimum allowed efficiency of 99.97% after 166 hours of exposure, we recommend replacing the filter every 160 hours of operation or sooner if the pressure drop increases by 50%. Examination of the filter showed that visible cracks appeared at the joints of the wooden frame and a portion of the sealant had pulled away from the frame. Since all of the DMSO will be trapped in the first HEPA filter, the second HEPA filter should not suffer from DMSO degradation. Thus the combined efficiency for the first filter (98.6%) and the second filter (99.97%) is 99.99996% for 0.3μm particles. If the first filter is replaced prior to its degradation, each of the filters will have 99.97% efficiency, and the combined efficiency will be 99.999991%. The collection efficiency for DMSO/HE aerosols will be much higher because the particle size is much greater

Degradation of HEPA filters exposed to DMSO

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Wilson, K.; Larsen, G. [Lawrence Livermore National Laboratory, CA (United States)] [and others

1995-02-01

Dimethyl sulfoxide (DMSO) sprays are being used to remove the high explosive (HE) from nuclear weapons in the process of their dismantlement. A boxed 50 cmf HEPA filter with an integral prefilter was exposed to DMSO vapor and aerosols that were generated by a spray nozzle to simulate conditions expected in the HE dissolution operation. After 198 hours of operation, the pressure drop of the filter had increased form 1.15 inches to 2,85 inches, and the efficiency for 0.3 {mu}m dioctyl sebacate (DOS) aerosols decreased form 99.992% to 98.6%. Most of the DMSO aerosols had collected as a liquid pool inside the boxed HEPA. The liquid was blown out of the filter exit with 100 cmf air flow at the end of the test. Since the filter still met the minimum allowed efficiency of 99.97% after 166 hours of exposure, we recommend replacing the filter every 160 hours of operation or sooner if the pressure drop increases by 50%. Examination of the filter showed that visible cracks appeared at the joints of the wooden frame and a portion of the sealant had pulled away from the frame. Since all of the DMSO will be trapped in the first HEPA filter, the second HEPA filter should not suffer from DMSO degradation. Thus the combined efficiency for the first filter (98.6%) and the second filter (99.97%) is 99.99996% for 0.3 {mu}m particles. If the first filter is replaced prior to its degradation, each of the filters will have 99.97% efficiency, and the combined efficiency will be 99.999991%. The collection efficiency for DMSO/HE aerosols will be much higher because the particle size is much greater.

Sensitive method for the determination of sup 1 sup 8 F attached to aerosol particles in a PET centre

CERN Document Server

Papp, Z

2002-01-01

A new grab sampling method has been developed for the measurement of sup 1 sup 8 F attached to aerosol particles. It is based on direct beta-counting of filtered aerosol sample over successive time intervals by an end-window Geiger-Mueller counter. The effect of the progeny of radon and thoron on the beta-counting rate is separated by analysing the decay curve. The defined solid angle absolute counting was used to evaluate the efficiencies for sup 1 sup 8 F and for the progeny of radon and thoron one by one. Absolute activity concentration of sup 1 sup 8 F can be determined with less than 10% systematic error. Glass-fibre filter and high sampling flow rate are applied, leading to a detection limit for sup 1 sup 8 F of less than 1 Bq m sup - sup 3. The method was tested under different circumstances in the PET centre of University of Debrecen, Hungary.

Precision and accuracy of β gauge for aerosol mass determinations

International Nuclear Information System (INIS)

Courtney, W.J.; Shaw, R.W.; Dzabay, T.G.

1982-01-01

Results of an experimental determination of the precision and the accuracy of a β-ray attenuation method for measurement of aerosol mass are presented. The instrumental precision for a short-term experiment was 25 μg for a 6.5-cm 2 deposit collected on approximately 1 mg/cm 2 Teflon filters; for a longer-term experiment the precision was 27 μg. The precision of the gravimetric determinations of aerosol deposits was 22 μg for Teflon filters weighed to 1 μg. Filter reorientation and air density changes that were able adversely to affect the β-ray attenuation results are discussed. β-ray attenuation results are in good agreement with gravimetric measurements on the same filter-collected aerosols. Using dichotomous samplers in Durham, NC, we collected 136 aerosol samples on Teflon filters in two size ranges. A regression line was calculated implicitly assuming errors in both measurements of mass. The 90% confidence intervals lay within 21 μg of the regression line for mean fine fraction aerosol mass loadings of 536 μg and within 19 μg of the regression line for mean coarse fraction aerosol mass loadings of 349 μg. Any bias between gravimetric and β-gauge mass measurements was found to be less than 5%

Particle Size Distribution of E-Cigarette Aerosols and the Relationship to Cambridge Filter Pad Collection Efficiency

Directory of Open Access Journals (Sweden)

Alderman Steven L.

2015-01-01

Full Text Available The relatively volatile nature of the particulate matter fraction of e-cigarette aerosols presents an experimental challenge with regard to particle size distribution measure-ments. This is particularly true for instruments requiring a high degree of aerosol dilution. This was illustrated in a previous study, where average particle diameters in the 10-50 nm range were determined by a high-dilution, electrical mobility method. Total particulate matter (TPM masses calculated based on those diameters were orders of magnitude smaller than gravimetrically determined TPM. This discrepancy was believed to result from almost complete particle evaporation at the dilution levels of the electrical mobility analysis. The same study described a spectral transmission measurement of e-cigarette particle size in an undiluted state, and reported particles from 210-380 nm count median diameter. Observed particle number concentrations were in the 109 particles/cm3 range. Additional particle size measurements described here also found e-cigarette particle size to be in the 260-320 nm count median diameter range. Cambridge filter pads have been used for decades to determine TPM yields of tobacco burning cigarettes, and collection of e-cigarette TPM by fibrous filters is predicted to be a highly efficient process over a wide range of filtration flow rates. The results presented in this work provide support for this hypothesis.

Formation and evolution of aerosols in filtered air and in natural air. Effect of radioactivity; Formation et evolution des aerosols dans l'air filtre et dans l'air naturel action de la radioactivite

Energy Technology Data Exchange (ETDEWEB)

Madelaine, G J [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-06-01

Results are presented concerning the formation, the evolution, the coagulation and the electrical charge of aerosols which form in natural filtered air containing only gaseous impurities, under the influence of solar light (photolysis) and of radioactive disintegrations (radiolysis). The modifications brought about in the aerosol by an increase in the sulphur dioxide content and in the natural radioactive gas content are studied. The work is then repeated with non-filtered natural atmospheric air. A comparison is also made of the behaviour of non-radioactive and radioactive particles (active thoron deposit). In conclusion, the possible consequences of these phenomena on the origin and the size distribution of particles occurring in the atmosphere is considered. (author) [French] On expose les resultats obtenus sur la formation, l'evolution, la coagulation et la charge electrique des aerosols qui se forment dans l'air naturel filtre, ne contenant que des impuretes gazeuses, sous l'influence de la lumiere solaire (photolyse) et des desintegrations radioactives (radiolyse). On examine les modifications apportees a l'aerosol forme par l'augmentation de la teneur de l'air en anhydride sulfureux et en gaz radioactif naturel. Cette etude est ensuite reprise mais avec de l'air naturel atmospherique non filtre. On compare egalement le comportement des particules non radioactives et radioactives (depot actif du thoron). En conclusion, on examine les consequences que peuvent avoir ces phenomenes sur l'origine et la granulometrie des particules contenues dans l'atmosphere. (auteur)

Air sampling by pumping through a filter: effects of air flow rate, concentration, and decay of airborne substances

OpenAIRE

Šoštarić, Marko; Petrinec, Branko; Babić, Dinko

2016-01-01

This paper tackles the issue of interpreting the number of airborne particles adsorbed on a filter through which a certain volume of sampled air has been pumped. This number is equal to the product of the pumped volume and particle concentration in air, but only if the concentration is constant over time and if there is no substance decomposition on the filter during sampling. If this is not the case, one must take into account the inconstancy of the concentration and the decay law for a give...

In-situ high efficiency filter testing at AEE Winfrith

International Nuclear Information System (INIS)

Fraser, D.C.

1977-01-01

This paper discusses experience in the testing of high efficiency filters in a variety of reactor and plant installations at AEE Winfrith. There is rarely any concern about the effectiveness of the filter as supplied by any reputable manufacturer. Experience has shown there is a need to check for defects in the installation of filters which could lead to by-passing of aerosols and it is desirable to perform periodical re-tests to ensure that no subsequent deterioration occurs. It is important to use simple, portable apparatus for such tests; methods based on the use of sodium chloride aerosols, although suitable for the testing of filters prior to installation, involve apparatus which is too bulky for in-situ testing. At Winfrith a double automatic Pollak counter has been developed and used routinely since 1970. The aerosol involved has a particle size far smaller than the size most likely to penetrate intact filters, but this is irrelevant when one is primarily interested in particles which by-pass the filter. Comparisons with other methods of testing filters will be described. There is remarkably good agreement between the efficiency of the filter installation as measured by a Pollak counter compared with techniques involving aerosols of sodium chloride and Dioctyl Phthalate (DOP), presumably because the leakage around the filter is independent of particle size

AMS-C14 analysis of graphite obtained with an Automated Graphitization Equipment (AGE III) from aerosol collected on quartz filters

Energy Technology Data Exchange (ETDEWEB)

Solís, C.; Chávez, E.; Ortiz, M.E.; Andrade, E. [Instituto de Física, Universidad Nacional Autónoma de México, 04510 México D.F. (Mexico); Ortíz, E. [Universidad Autónoma Metropolitana, Unidad Azcapotzalco, México D.F. (Mexico); Szidat, S. [Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern (Switzerland); Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); Wacker, L. [Laboratory of Ion Physics, ETH, Honggerberg, Zurich (Switzerland)

2015-10-15

AMS-{sup 14}C applications often require the analysis of small samples. Such is the case of atmospheric aerosols where frequently only a small amount of sample is available. The ion beam physics group at the ETH, Zurich, has designed an Automated Graphitization Equipment (AGE III) for routine graphite production for AMS analysis from organic samples of approximately 1 mg. In this study, we explore the potential use of the AGE III for graphitization of particulate carbon collected in quartz filters. In order to test the methodology, samples of reference materials and blanks with different sizes were prepared in the AGE III and the graphite was analyzed in a MICADAS AMS (ETH) system. The graphite samples prepared in the AGE III showed recovery yields higher than 80% and reproducible {sup 14}C values for masses ranging from 50 to 300 μg. Also, reproducible radiocarbon values were obtained for aerosol filters of small sizes that had been graphitized in the AGE III. As a study case, the tested methodology was applied to PM{sub 10} samples collected in two urban cities in Mexico in order to compare the source apportionment of biomass and fossil fuel combustion. The obtained {sup 14}C data showed that carbonaceous aerosols from Mexico City have much lower biogenic signature than the smaller city of Cuernavaca.

Quick-change filter cartridge

Science.gov (United States)

Rodgers, John C.; McFarland, Andrew R.; Ortiz, Carlos A.

1995-01-01

A quick-change filter cartridge. In sampling systems for measurement of airborne materials, a filter element is introduced into the sampled airstream such that the aerosol constituents are removed and deposited on the filter. Fragile sampling media often require support in order to prevent rupture during sampling, and careful mounting and sealing to prevent misalignment, tearing, or creasing which would allow the sampled air to bypass the filter. Additionally, handling of filter elements may introduce cross-contamination or exposure of operators to toxic materials. Moreover, it is desirable to enable the preloading of filter media into quick-change cartridges in clean laboratory environments, thereby simplifying and expediting the filter-changing process in the field. The quick-change filter cartridge of the present invention permits the application of a variety of filter media in many types of instruments and may also be used in automated systems. The cartridge includes a base through which a vacuum can be applied to draw air through the filter medium which is located on a porous filter support and held there by means of a cap which forms an airtight seal with the base. The base is also adapted for receiving absorbing media so that both particulates and gas-phase samples may be trapped for investigation, the latter downstream of the aerosol filter.

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

International Nuclear Information System (INIS)

2000-01-01

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

Measurement of radioactive aerosols as an original indicator of atmospheric pollution in urban areas

International Nuclear Information System (INIS)

Le Petit, G.; Millies-Lacroix, J. C.

1998-01-01

The Service Radioanalyses, Chimie et Environnment (Departement Analyses Surveillance de l'Environnement) of the French Atomic Energy Commission, located in suburban Paris, has for many years been conducting atmospheric radioactivity measurements. Since 1994, the laboratory has been using high volume air samplers equipped with filters for the weekly collection of atmospheric aerosols at a mean rate of about 600 m 3 .h -1 . The polypropylene filters, with a collection efficiency in excess of 93%, are compacted after sampling. The atmospheric radioactivity is measured by HP Ge gamma spectrometry after decay of short-lived natural relationship products. A study conducted in 1996 shows good correlation between the evolution with time of some of the indicators routinely used by AIRPARIF, the organization in charge of monitoring the air quality in the Ile-de-France region, to measure atmospheric pollution in the Paris area (SO 2 , NO) and that related to radioactivity of terrestrial ( 210 Pb, 40 K) and anthropogenic ( 137 Cs) origin, as well as the amount of aerosols collected. Further, the distribution in time of the atmospheric radioactivity of cosmogenic origin ( 7 Be) shows a yearly evolution somewhat similar to that observed with ozone

Performance testing of HEPA filters: Progress towards a European standard procedure

Energy Technology Data Exchange (ETDEWEB)

Dyment, J.

1997-08-01

Proposals for a future European testing procedure for {open_quotes}High Efficiency Particulate Air Filters (HEPA and ULPA){close_quotes} are being developed by CEN (Comite Europeen de Normalisation). The new standard will be given the status of national standard in participating countries, conflicting national standards being withdrawn. The standard will comprise 5 parts covering the grouping and classification of HEPA and ULPA filters according to their efficiency, fundamental principles of testing, marking etc (in part 1). Part 2 will cover aerosol production, measurement principles, counting equipment and statistics. Parts 3-5 will cover testing flat sheet media, leak testing of filter elements and the efficiency testing of filter elements respectively. The efficiency test methods allow the use of either homogeneous monodisperse or polydisperse aerosols for the determination of particulate filtration efficiencies as a function of particle size. The particle size at which maximum penetration occurs is first determined in flat sheet media tests; tests on filter elements (constructed using the same filter medium) may be carried out using either a homogeneous monodisperse aerosol of the size at which maximum penetration occurs (MPPS) or a polydisperse aerosol whose median size is close to the MPPS. Tests with monodisperse aerosols may be conducted using condensation nucleus counting equipment; tests using polydisperse test aerosols require the use of optical sizing particle counters. When determining the efficiency of filter elements the downstream aerosol concentrations may be determined from air samples obtained using either an overall method (single point sampling after mixing) or a scan method. The scan method also allows {open_quotes}local{close_quotes} efficiency values to be determined. 1 ref., 1 fig., 1 tab.

In-situ testing of high efficiency filters at AEE Winfrith

International Nuclear Information System (INIS)

Fraser, D.C.

1977-10-01

This paper discusses experience in the testing of high efficiency filters in a variety of reactor and plant installations at AEE Winfrith. There is rarely any concern about the effectiveness of the filter as supplied by any reputable manufacturer. Experience has shown there is a need to check for defects in the installation of filters which could lead to by-passing of aerosols and it is desirable to perform periodical re-tests to ensure that no subsequent deterioration occurs. It is important to use simple, portable apparatus for such tests; methods based on the use of sodium chloride aerosols, although suitable for the testing of filters prior to installation, involve apparatus which is too bulky for in-situ testing. At Winfrith a double automatic Pollak counter has been developed and used routinely since 1970. The aerosol involved has a particle size far smaller than the size most likely to penetrate intact filters, but this is irrelevant when one is primarily interested in particles which by-pass the filter. Comparisons with other methods of testing filters will be described. There is remarkably good agreement between the efficiency of the filter installation as measured by a Pollak counter compared with techniques involving aerosols of sodium chloride and di octyl phthalate (DOP), presumably because the leakage around the filter is independent of particle size. (author)

Current Status of Aerosol Generation and Measurement Facilities for the Verification Test of Containment Filtered Venting System in KAERI

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Il; An, Sang Mo; Ha, Kwang Soon; Kim, Hwan Yeol [KAERI, Daejeon (Korea, Republic of)

2016-05-15

In this study, the design of aerosol generation and measurement systems are explained and present circumstances are also described. In addition, the aerosol test plan is shown. Containment Filtered Venting System (FCVS) is one of the safety features to reduce the amount of released fission product into the environment by depressurizing the containment. Since Chernobyl accident, the regulatory agency in several countries in Europe such as France, Germany, Sweden, etc. have been demanded the installation of the CFVS. Moreover, the feasibility study on the CFVS was also performed in U.S. After the Fukushima accident, there is a need to improve a containment venting or installation of depressurizing facility in Korea. As a part of a Ministry of Trade, Industry and Energy (MOTIE) project, KAERI has been conducted the integrated performance verification test of CFVS. As a part of the test, aerosol generation system and measurement systems were designed to simulate the fission products behavior. To perform the integrated verification test of CFVS, aerosol generation and measurement system was designed and manufactured. The component operating condition is determined to consider the severe accident condition. The test will be performed in normal conditions at first, and will be conducted under severe condition, high pressure and high temperature. Undesirable difficulties which disturb the elaborate test are expected, such as thermophoresis on the pipe, vapor condensation on aerosol, etc.

Multivariate regression analysis for determining short-term values of radon and its decay products from filter measurements

International Nuclear Information System (INIS)

Kraut, W.; Schwarz, W.; Wilhelm, A.

1994-01-01

A multivariate regression analysis is applied to decay measurements of α-resp. β-filter activcity. Activity concentrations for Po-218, Pb-214 and Bi-214, resp. for the Rn-222 equilibrium equivalent concentration are obtained explicitly. The regression analysis takes into account properly the variances of the measured count rates and their influence on the resulting activity concentrations. (orig.) [de

Aerosol-phase Activity of Iodine Captured from a Triiodide Resin Filter on Fine Particles Containing an Infectious Virus

Science.gov (United States)

2015-01-01

filtration pro cess must be expected to experience attenuation at the point of aerosol contact with the mucosal surface. The effect of environmental...nebulizer were con nected using 79 mm ID, 127 mm OD conductive electrical tubing (TSI) to minimize particle attraction. Downstream of the filter holder...Na2CO3 (Gooch and Valker 1905; OSHA 1994). The negative control was bags filled with clean air and processed similarly immedi ately after filling. Iodine

Papers of the 14. french congress on aerosols CFA 98; Actes du 14. congres francais sur les aerosols CFA 98

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This french congress on the aerosols took place in Paris the 8 and 9 december 1998. It was presented in four main themes: the aerosols in the environment; the bio-aerosols, filtering and purifying; the aerosols metrology; the aerosols physic and application. Seven papers have been analyzed in INIS data base for their specific interest in nuclear industry. Eight other ones are analyzed in ETDE data base. (A.L.B.)

Effect of humidity on the filter pressure drop

International Nuclear Information System (INIS)

Vendel, J.; Letourneau, P.

1995-01-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO 2 ). Cesium hydroxyde (CsOH) of size of 2 μ M AMMD has been generated by an ultrasonic generator and the 0.7 μm AMMD titanium oxyde has been dispersed by a open-quotes turn-tableclose quotes generator. As it is noted in the BISWAS'publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced

Effect of humidity on the filter pressure drop

Energy Technology Data Exchange (ETDEWEB)

Vendel, J.; Letourneau, P. [Institut de Protection et de Surete Nucleaire, Gif-sur-Yvette (France)

1995-02-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO{sub 2}). Cesium hydroxyde (CsOH) of size of 2 {mu} M AMMD has been generated by an ultrasonic generator and the 0.7 {mu}m AMMD titanium oxyde has been dispersed by a {open_quotes}turn-table{close_quotes} generator. As it is noted in the BISWAS`publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced.

Atmospheric aerosol studies using the 'Gent' stacked filter unit and other aerosol collectors, with multi-elemental analysis of the samples by nuclear-related analytical techniques. Appendix 4

International Nuclear Information System (INIS)

Maenhaut, Willy; Francois, Filip; Cafmeyer, Jan; Okunade, Olusola

1995-01-01

Our research within the core programme of the Co-ordinated Research Programme (CRP) on Air Pollution is described. This included the analysis of the analytical quality control Nuclepore filter samples, work on the calibration of the PM10 inlet of the 'Gent' stacked filter unit (SFU) sampler, and an aerosol study with this SFU sampler at an urban residential site in Gent. The calibration of the Gent PM10 inlet was done through intercomparisons with commercially available PM10 samplers, and quite reasonable agreement was obtained. For the study at the urban residential site, a total of 118 SFU samples were collected. The samples were analyzed for the particulate mass, black carbon and up to 29 elements. The elements were measured by PIXE and short-irradiation INAA. Median atmospheric concentrations and enrichment factors were calculated for the fine and coarse size fractions, and average FINE/COARSE ratios were derived. The median concentrations were compared with those from a study, done at the same site in the fall of 1986. The levels of the automotive elements Pb and Br had decreased by a factor of about three relative to 1986, but most other elements exhibited very similar concentrations. A brief overview is given of the status in our various regional and global scale aerosol studies. Finally, our plans for future work are given. (author)

Filtration of aerosols produced by a sodium fire

International Nuclear Information System (INIS)

Duverger de Cuy, G.; Colome, J.

1977-01-01

The containment system of the Super Phenix reactor takes account of the possibility of contaminated sodium fires, particularly in the vicinity of the fuel storage drum. It is thus necessary to contain the emitted radioactivity associated with a quantity of sodium aerosols of the order of some 10 g/m 3 . Investigations previously carried out had shown that the retention capacity of high-efficiency asbestos filters was clearly insufficient. A new research programme on the filtration of sodium aerosols has thus been worked out with the aim of: gaining a better understanding of the granulometry of the aerosols produced by the fire; checking the efficiency of the new glass-fibre media of which high-efficiency filters are composed; selecting a prefiltering system which, in conjunction with the high-efficiency filter, would ensure a suitable retention capacity for the whole unit. The following prefilters are under investigation: agglomerating cyclones; fabric prefilters (dense filter media - variable density filters - bag filters); water prefilters; sand prefilters. The experimental equipment on which this programme has been based is presented. Results have so far been obtained for agglomerating cyclones (recirculating loop with a cyclone of 95% efficiency), for a number of textile prefilters and for the retention capacity of high-efficiency filters

Regional and global atmospheric aerosol studies using the ''Gent'' stacked filter unit sampler and other aerosol collectors, with multi-elemental analysis of the samples by nuclear-related analytical techniques

International Nuclear Information System (INIS)

Maenhaut, W.; Francois, F.; Salma, I.; Cafmeyer, J.; Gilot, C.

1994-01-01

The ''Gent'' staked filter unit sampler and other collection devices are used in regional and global scale studies on the tropospheric atmospheric aerosols, its composition, sources and fate. The aerosol samples are analyzed by particle-induced X-ray emission analysis, instrumental neutron activation analysis, ion chromatography, a light reflectance technique (for determining black carbon), and gravimetry (for measuring the particular mass). In evaluating the data, use is made of receptor modelling techniques, transport models and wind sector analysis, and also of air mass trajectories and other meteorological information. Preliminary results from a long-term study in southern Norway are presented. It is suggested that the anthropogenic and soil dust aerosol components are mainly adverted to southern Norway by long-range transport and that the major fraction of the submicrometer particle mass is from anthropogenic origin. Preliminary results are also presented for an intensive study in southern Africa. On the basis of the data for two sites (about 40 km apart) in the Kruger National Park it was concluded that regionally representative aerosol samples were collected and that the biomass burning products account for more than 50% of the fine particle mass. Finally, our plans for future work are given. (author). 70 refs, 4 figs, 1 tab

Neutron activation analysis of atmospheric aerosols

International Nuclear Information System (INIS)

Riekstinya, D.V.; Mednis, I.V.; Veveris, O.Eh.

1987-01-01

A review of studies by Soviet and foreign authors on radioactivation analysis is presented. Instrumental neutron activation analysis (INAA) techniques have been developed providing the possibility to determine a number of elements in very small portions of aerosols for pollutanless areas of the Earth. Two ways of INAA are presented: with long- and short-living radionuclides. The Antarctic and the Indian Ocean aerosol samples have been analysed for 26 microelements. It has been stated that restrictions of the detection limits attained relate to high proportions of certain elements and their nonhomogeneous distribution in filters. The detection limits can be lowered by the filtered air volume growth per unit of the filter area

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

Comparative study of in-situ filter test methods

International Nuclear Information System (INIS)

Marshall, M.; Stevens, D.C.

1981-01-01

Available methods of testing high efficiency particulate aerosol (HEPA) filters in-situ have been reviewed. In order to understand the relationship between the results produced by different methods a selection has been compared. Various pieces of equipment for generating and detecting aerosols have been tested and their suitability assessed. Condensation-nuclei, DOP (di-octyl phthalate) and sodium-flame in-situ filter test methods have been studied, using the 500 cfm (9000 m 3 /h) filter test rig at Harwell and in the field. Both the sodium-flame and DOP methods measure the penetration through leaks and filter material. However the measured penetration through filtered leaks depends on the aerosol size distribution and the detection method. Condensation-nuclei test methods can only be used to measure unfiltered leaks since condensation nuclei have a very low penetration through filtered leaks. A combination of methods would enable filtered and unfiltered leaks to be measured. A condensation-nucleus counter using n-butyl alcohol as the working fluid has the advantage of being able to detect any particle up to 1 μm in diameter, including DOP, and so could be used for this purpose. A single-particle counter has not been satisfactory because of interference from particles leaking into systems under extract, particularly downstream of filters, and because the concentration of the input aerosol has to be severely limited. The sodium-flame method requires a skilled operator and may cause safety and corrosion problems. The DOP method using a total light scattering detector has so far been the most satisfactory. It is fairly easy to use, measures reasonably low values of penetration and gives rapid results. DOP has had no adverse effect on HEPA filters over a long series of tests

Advanced Filter Technology For Nuclear Thermal Propulsion

Science.gov (United States)

Castillon, Erick

2015-01-01

The Scrubber System focuses on using HEPA filters and carbon filtration to purify the exhaust of a Nuclear Thermal Propulsion engine of its aerosols and radioactive particles; however, new technology may lend itself to alternate filtration options, which may lead to reduction in cost while at the same time have the same filtering, if not greater, filtering capabilities, as its predecessors. Extensive research on various types of filtration methods was conducted with only four showing real promise: ionization, cyclonic separation, classic filtration, and host molecules. With the four methods defined, more research was needed to find the devices suitable for each method. Each filtration option was matched with a device: cyclonic separators for the method of the same name, electrostatic separators for ionization, HEGA filters, and carcerands for the host molecule method. Through many hours of research, the best alternative for aerosol filtration was determined to be the electrostatic precipitator because of its high durability against flow rate and its ability to cleanse up to 99.99% of contaminants as small as 0.001 micron. Carcerands, which are the only alternative to filtering radioactive particles, were found to be non-existent commercially because of their status as a "work in progress" at research institutions. Nevertheless, the conclusions after the research were that HEPA filters is recommended as the best option for filtering aerosols and carbon filtration is best for filtering radioactive particles.

Papers of the 14. french congress on the aerosols CFA 98; Actes du 14. congres francais sur les aerosols CFA 98

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This french congress on the aerosols took place in Paris the 8 and 9 december 1998. It was presented in four main themes: the aerosols in the environment; the bio-aerosols, filtering and purifying; the aerosols metrology; the aerosols physic and application. Eight papers have been analyzed in ETDE data base showing the importance of the aerosols physic knowledge in the air quality and seven other in the INIS data base for their specific interest in the nuclear industry. (A.L.B.)

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

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)

Measurement of radioactive aerosols as an original indicator of atmospheric pollution in urban areas

International Nuclear Information System (INIS)

Le Petit, G.; Millies-Lacroix, J.-C.; Simon, F.

1998-01-01

The Service Radioanalyses, Chimie et Environnement (Departement Analyses Surveillance de l'Environnement) of the French Atomic Energy Commission, located in suburban Paris, has for many years been conducting atmospheric radioactivity measurements. Since 1994, the laboratory has been using high volume air samplers equipped with filters for the weekly collection of atmospheric aerosols at a mean rate of about 600 m 3 .h -1 . The polypropylene filters, with a collection efficiency in excess of 93%, are compacted after sampling. The atmospheric radioactivity is measured by HP Ge gamma spectrometry after decay of short-lived natural relationship products. A study conducted in 1996 shows good correlation between the evolution with time of some of the indicators routinely used by AIRPARIF, the organization in charge of monitoring of the air quality in the Ile-de-France region, to measure atmospheric pollution in the Paris area (SO 2 , NO) and that related to radioactivity of terrestrial ( 210 Pb, 40 K) and anthropogenic ( 137 Cs) origin, as well as the amount of aerosols collected. Further, the distribution in time of the atmospheric radioactivity of cosmogenic origin ( 7 Be) shows a yearly evolution somewhat similar to that observed with ozone. (author). 16 refs., 21 figs., 1 tab

Evaluation of the effectiveness of an antimicrobial air filter to avoid porcine reproductive and respiratory syndrome virus (PRRSV) aerosol transmission, after 16 months of exposure to a commercial swine environmental conditions

Energy Technology Data Exchange (ETDEWEB)

Batista, L. [Boehringer Ingelheim Vetmedica Inc., St. Joseph, MO (United States); Pouliot, F.; Urizar, L. [Centre de developpement du porc du Quebec Inc., Quebec City, PQ (Canada)

2010-07-01

The effectiveness of Noveko's antimicrobial filter was evaluated after 16 months of exposure to commercial swine production. The experiment involved the use of a scaled model of a commercial swine facility consisting of 2 small chambers connected by a duct containing the filters. A 5 kg naive pig was placed in the reception chamber for a period of 6 hours after aerosolization with porcine reproductive and respiratory syndrome virus (PRRSV). Blood samples from pigs were collected before and after aerosolization to test for the presence of PRRSV RNA. Only blood samples were tested for PRRSV antibodies by IDEXX 2XR ELISA. None of the 9 pigs tested were found to be infected. The study showed that the technology used to integrate the antimicrobial agent into the filter fibers allows the filter combination to withstand extreme weather and endure commercial swine production for at least 16 months, and can maintain its effectiveness to avoid airborne transmission of PRRSV.

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.

Permeability optimization and performance evaluation of hot aerosol filters made using foam incorporated alumina suspension.

Science.gov (United States)

Innocentini, Murilo D M; Rodrigues, Vanessa P; Romano, Roberto C O; Pileggi, Rafael G; Silva, Gracinda M C; Coury, José R

2009-02-15

Porous ceramic samples were prepared from aqueous foam incorporated alumina suspension for application as hot aerosol filtering membrane. The procedure for establishment of membrane features required to maintain a desired flow condition was theoretically described and experimental work was designed to prepare ceramic membranes to meet the predicted criteria. Two best membranes, thus prepared, were selected for permeability tests up to 700 degrees C and their total and fractional collection efficiencies were experimentally evaluated. Reasonably good performance was achieved at room temperature, while at 700 degrees C, increased permeability was obtained with significant reduction in collection efficiency, which was explained by a combination of thermal expansion of the structure and changes in the gas properties.

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

Changes in collection efficiency in nylon net filter media through magnetic alignment of elongated aerosol particles.

Science.gov (United States)

Lam, Christopher O; Finlay, W H

2009-10-01

Fiber aerosols tend to align parallel to surrounding fluid streamlines in shear flows, making their filtration more difficult. However, previous research indicates that composite particles made from cromoglycic acid fibers coated with small nanoscaled magnetite particles can align with an applied magnetic field. The present research explored the effect of magnetically aligning these fibers to increase their filtration. Nylon net filters were challenged with the aerosol fibers, and efficiency tests were performed with and without a magnetic field applied perpendicular to the flow direction. We investigated the effects of varying face velocities, the amount of magnetite material on the aerosol particles, and magnetic field strengths. Findings from the experiments, matched by supporting single-fiber theories, showed significant efficiency increases at the low face velocity of 1.5 cm s(-1) at all magnetite compositions, with efficiencies more than doubling due to magnetic field alignment in certain cases. At a higher face velocity of 5.12 cm s(-1), filtration efficiencies were less affected by the magnetic field alignment being, at most, 43% higher for magnetite weight compositions up to 30%, while at a face velocity of 10.23 cm s(-1) alignment effects were insignificant. In most cases, efficiencies became independent of magnetic field strength above 50 mT, suggesting full alignment of the fibers. The present data suggest that fiber alignment in a magnetic field may warrant applications in the filtration and detection of fibers, such as asbestos.

Evaluating the use of PAO (4 cSt polyalphaoelfin) oil instead of DOP (di-octyl phthalate) oil for measuring the aerosol capture of nuclear canister filters

Energy Technology Data Exchange (ETDEWEB)

Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-07-18

This document details the distinction between using PAO (4 cSt polyalphaoelfin) oil instead of DOP (di-octyl phthalate) oil for measuring the aerosol capture of filters. This document is developed to justify the use of PAO rather than DOP for evaluating the performance of filters in the SAVY 4000 and Hagan containers. The design criteria (Anderson et al, 2012) for purchasing SAVY 4000 containers and the Safety Analysis Report for the SAVY 4000 Container Series specified that the filter must “capture greater than 99.97% of 0.45 μm mean diameter dioctyl phthalate (DOP) aerosol at the rated flow with a DOP concentration of 65±15 micrograms per liter.”This corresponds to a leakage percent of 0.03% (3.0x10^-2). The density of DOP oil is 985 kg/m³ and the density of PAO oil is 819 kg/m³. ATI Test Inc measured the mass mean diameter of aerosol distributions produced by a single Laskin type III-A nozzle operating at a 20 psig air pressure as 0.563 μm for DOP oil and 0.549 μm for PAO oil. (See Appendix A.) For both types of oil in this document, the single fiber method calculated the leakage percent to be 4.4x10^-5 for DOP oil and 4.7x10^-5 for PAO oil. Although the percent error between these two quantities is 7.7%, these calculated leakage percent values are more than two orders of magnitude less than the criterion specified in the SAVY canister SAR. As a point of reference, the photometer used to measure the SAVY canister filter performance cannot resolve values for the leakage percent below 1.0x10^-5. Additionally, over a range of particle sizes from 0.01 μm to 3.0 μm, there was less than 4.0x10^-5 error between the calculated filter efficiency for the two types of oil at any particular particle size diameter. In conclusion, the difference between using DOP and PAO for testing SAVY canister filters is of inconsequential concern.

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)

Papers of the 14. french congress on aerosols CFA 98

International Nuclear Information System (INIS)

2000-01-01

This french congress on the aerosols took place in Paris the 8 and 9 december 1998. It was presented in four main themes: the aerosols in the environment; the bio-aerosols, filtering and purifying; the aerosols metrology; the aerosols physic and application. Seven papers have been analyzed in INIS data base for their specific interest in nuclear industry. Eight other ones are analyzed in ETDE data base. (A.L.B.)

Composition and sources of carbonaceous aerosols in Northern Europe during winter

NARCIS (Netherlands)

Glasius, M.; Hansen, A.M.K.; Claeys, M.; Henzing, J.S.; Jedynska, A.D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J.K.; Spindler, G.; Stenström, K.E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K.E.

2018-01-01

Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The

Problems presented by the filtration and sampling of aerosols in the atomic energy programme; Problemes poses par la filtration et le prelevement des aerosols dans le cadre de l'energie atomique

Energy Technology Data Exchange (ETDEWEB)

Cochinal, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

The maximum permissible limits for radioactive aerosols are much lower than those for aerosols encountered in the non-nuclear industries. These limits depend on numerous factors such as: nature of the radiation, half-life, etc. The radioactive aerosols can be prepared by various methods. The filtering of the air in high activity laboratories or in plutonium treatment factories necessitates an installation consisting of: - aspiration filters, - extraction filters of very high efficiency (those used for {alpha} emitter cells: designed to be replaced without incurring contamination risks; those used for {gamma} emitter cells: designed to be replaced by remote control). The filtering in nuclear reactors is also effectuated by filter papers: - the G1 reactor with open circuit: the air coolant is entirely filtered at the entry and on leaving; - the G2, G3 and EDF1 reactors with closed circuits: filtering under pressure of a small portion of the coolant gas. (author) [French] Les limites maxima permises des aerosols radioactifs sont beaucoup plus faibles que celles des aerosols rencontres dans l'industrie classique. Elles dependent de nombreux facteurs tel que: nature du rayonnement, periode radioactive, etc... La formation des aerosols radioactifs est de nature diverse. La filtration des laboratoires de haute activite, ou d'usines d'elaboration de plutonium conduit a des types d'installations comportant: - des filtres d'aspiration; - des filtres d'extraction a rendement extremement eleve (type pour cellules emettrices {alpha} concu pour etre change sans risque de contamination, type pour cellules emettrices {gamma}: concu pour etre change a distance) La filtration des reacteurs nucleaires sont egalement effectuee par des papiers filtres: - reacteur G1 a circuit ouvert: air de refroidissement totalement filtre a l'aspiration et a l'extraction; - reacteurs G2, G3, EDF1: a circuit ferme: filtration sous pression d'une faible partie du gaz de refroidissement. (auteur)

Examination of quantitative accuracy of PIXE analysis for atmospheric aerosol particle samples. PIXE analysis of NIST air particulate on filter media

International Nuclear Information System (INIS)

Saitoh, Katsumi; Sera, Koichiro

2005-01-01

In order to confirm accuracy of the direct analysis of filter samples containing atmospheric aerosol particles collected on a polycarbonate membrane filter by PIXE, we carried out PIXE analysis on a National Institute of Standards and Technology (NIST, USA) air particulate on filter media (SRM 2783). For 16 elements with NIST certified values determined by PIXE analysis - Na, Mg, Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb - quantitative values were 80-110% relative to NIST certified values except for Na, Al, Si and Ni. Quantitative values of Na, Al and Si were 140-170% relative to NIST certified values, which were all high, and Ni was 64%. One possible reason why the quantitative values of Na, Al and Si were higher than the NIST certified values could be the difference in the X-ray spectrum analysis method used. (author)

Off-gas filter system of the SNR-300

International Nuclear Information System (INIS)

Boehm, L.; Jordan, S.; Schikarski, W.

1975-01-01

The Reventing-Exventing-System of the German Liquid Metal Fast Breeder Prototype SNR-300 is described. After an accident with major damage to the core the ventilation valves are quickly closed. At the same time the blower of the reventing system evacuates the reventing gap up to a pressure difference of 2 mbar between the containment and the outer atmosphere. This pressure difference prevents a leakage from the containment to the outside. The revented gas is recirculated into the outer-containment. Leaks from the atmosphere and possibly from the inner containment into the reventing gap increase the pressure in the outer-containment. Therefore depending on the pressure build-up which is determined by the course of the accident, it is necessary to exvent the containment after several days. The exvented gas is filtered by a filter combination consisting of pre-filters, charcoal-filters and HEPA-filters. Because accidental sodium fires produce high concentrations of sodium oxide-aerosols this filter system must resist chemical aggressive aerosols. (U.S.)

Analysis of an MCU HEPA filter

Energy Technology Data Exchange (ETDEWEB)

Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fondeur, F. F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-01-01

A series of direct analyses on three portions (inlet, center, and outlet) of the High Efficiency Particulate Air (HEPA) filter material from the Modular Caustic-Side Solvent Extraction Unit (MCU) have been performed; this includes x-ray methods such as X-Ray Diffraction (XRD), Contained Scanning Electron Microscopy (CSEM) and X-Ray Fluorescence (XRF), as well as Fourier Transform InfraRed spectroscopy (FTIR). Additionally, two leaching studies (one with water, one with dichloromethane) have been performed on three portions (inlet, center, and outlet) of the HEPA filter material, with the leachates being analyzed by Inductively-coupled plasma emission spectroscopy (ICPES), Semi-Volatile Organic Analysis (SVOA) and gammascan. From the results of the analyses, SRNL feels that cesium-depleted solvent is being introduced into the HEPA filter. The most likely avenue for this is mechanical aerosolization of solvent, where the aerosol is then carried along an airstream into the HEPA filter. Once introduced into the HEPA filter media, the solvent wicks throughout the material, and migrates towards the outlet end. Once on the outlet end, continual drying could cause particulate flakes to exit the filter and travel farther down the airstream path.

Development of the quickmix injector for in-situ filter testing

International Nuclear Information System (INIS)

Costigan, G.; Loughborough, D.

1993-01-01

In-situ filter testing is routinely carried out on nuclear ventilation plant to assess the effectiveness of installed filter systems. Ideally the system is tested by introducing a sub-micron aerosol upstream of the filter, in such a way as to present a uniform challenge to the whole of the upstream filter face. Samples are withdrawn from upstream and downstream of the filter, and the respective concentrations are used to calculate the system (or filter) efficiency. These requirements are documented in the Atomic Energy Code of Practice, AECP 1054. The Filter Development Section at Harwell Laboratory has been investigating methods of improving the accuracy and reliability of the in-situ filter test over the past ten years. The programme has included the evaluation of devices used to mix the aerosol and multi-point samplers to obtain representative aerosol samples. This paper reports the results of laboratory trials on the open-quotes QUICKMIXclose quotes injector developed and patented by Harwell. The Quickmix injector is designed to mix the test aerosol with the air stream and thereby reduce the duct length required to produce uniform concentrations. The injector has been tested in ducts ranging from 150 mm diameter to 610 mm square, at air velocities up to 26 m/s. Upstream mixing lengths required to achieve a ± 10% concentration variation on the mean were reduced to between 2 and 5 duct diameters, with a very small pressure drop. This simple, compact device is being installed in new and existing plants in the UK to improve the accuracy and reliability of in-situ filter testing. Some examples of plant applications are given, together with some of the first results from operating plant

High efficiency filtration of liquid-metal-generated aerosols

International Nuclear Information System (INIS)

First, M.W.

1977-01-01

This paper will present data on filter performance for the range of sodium-containing aerorols that can result from large and small releases of hot metallic sodium into confined spaces containing air or special atmospheres and will compare the particle collection effectiveness, space and power requirements, service life, and disposal of the collected materials for the several options. Prompt reduction of in-vessel aerosols with methods that induce rapid coagulation and sedimentation by the application of violent turbulance, sonic energy, or electrostatic attraction; by aerosol scavenging with massive inert dust additions; and by a number of other innovative methods is of special interest because of their potential ability to bring down the aerosol cloud very rapidly and thereby to reduce vessel out-leakage drastically; as well as to relieve the particle load on filters. These methods will be examined as supplements to filtration methods for control of sodium-containing aerosols

Remote aerosol testing of large size HEPA filter banks

International Nuclear Information System (INIS)

Franklin, B.; Pasha, M.; Bronger, C.A.

1987-01-01

Different methods of testing HEPA filter banks are described. Difficulties in remote testing of large banks of HEPA filters in series with minimum distances between banks, and with no available access upstream and downstream of the filter house, are discussed. Modifications incorporated to make the filter system suitable for remote testing without personnel re-entry into the filter house are described for a 51,000 m/sup 3//hr filter unit at the WIPP site

Estimation of Uncertainty in Aerosol Concentration Measured by Aerosol Sampling System

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Chan; Song, Yong Jae; Jung, Woo Young; Lee, Hyun Chul; Kim, Gyu Tae; Lee, Doo Yong [FNC Technology Co., Yongin (Korea, Republic of)

2016-10-15

FNC Technology Co., Ltd has been developed test facilities for the aerosol generation, mixing, sampling and measurement under high pressure and high temperature conditions. The aerosol generation system is connected to the aerosol mixing system which injects SiO{sub 2}/ethanol mixture. In the sampling system, glass fiber membrane filter has been used to measure average mass concentration. Based on the experimental results using main carrier gas of steam and air mixture, the uncertainty estimation of the sampled aerosol concentration was performed by applying Gaussian error propagation law. FNC Technology Co., Ltd. has been developed the experimental facilities for the aerosol measurement under high pressure and high temperature. The purpose of the tests is to develop commercial test module for aerosol generation, mixing and sampling system applicable to environmental industry and safety related system in nuclear power plant. For the uncertainty calculation of aerosol concentration, the value of the sampled aerosol concentration is not measured directly, but must be calculated from other quantities. The uncertainty of the sampled aerosol concentration is a function of flow rates of air and steam, sampled mass, sampling time, condensed steam mass and its absolute errors. These variables propagate to the combination of variables in the function. Using operating parameters and its single errors from the aerosol test cases performed at FNC, the uncertainty of aerosol concentration evaluated by Gaussian error propagation law is less than 1%. The results of uncertainty estimation in the aerosol sampling system will be utilized for the system performance data.

A rapid method for determining the relative solubility of plutonium aerosols

International Nuclear Information System (INIS)

Miglio, J.J.; Muggenburg, B.A.; Brooks, A.L.

1977-01-01

An in vitro system for rapidly determining the relative solubilities of plutonium-containing aerosols produced at various temperatures has been developed. Aerosols were prepared by nebulizing a solution of Pu IV in 1 M HCl and by subsequent heating at 50, 325, 600, 900, 1150 and 1300 degrees C. These aerosols were then evaluated as to relative solubility and the results compared with in vivo data from beagle dogs and Chinese hamsters. Aerosol samples from animal inhalation exposures were collected on filters and a section was sandwiched between 100 nm membranes held in a two-piece, cylindrical polyethylene holder. The holder and filter were placed in a container of solvent and stirred gently, after which the filter and solvent were separately analyzed for Pu. The effects of solvent composition, volume and temperature as well as immersion time were investigated. The results showed that using a solvent of 0.1 N HCl at 23 degrees C and an immersion time of 2 hr dissolved a sufficient amount of plutonium as to be easily assayed with a liquid scintillation counter and will provide a rapid estimate of the solubility rate of the aerosol. The in vivo and in vitro results were in relative agreement; as the production temperature of the aerosol increased, the solubility decreased. (author)

Physical distributions of radon decay chain activities in air

International Nuclear Information System (INIS)

Rolle, R.

2004-01-01

for evaluating diurnal concentration cycles in flow systems. The Rn decay product atoms are formed almost instantly as nanometer sized clusters and these can attach to any available surfaces, which may predominantly be that of aerosols, usually in the accumulation mode size range around 200 nm. Measurement of their distribution in these two major (or additional) size ranges permits the improved determination of otherwise possibly difficult to asses flow parameters, such as activity loss to solid surfaces in a room, and analogously improved lung model exposure estimation. Efficient in-line measurement on screen and filter, with minimized entry losses, can readily yield quality data. Accurate time-resolved measurement of individual concentrations, with preferably good spatial representation in extended flow systems, facilitates an improved assessment of a dynamic flow system, approximated in compartment flow models, and thus presents a basis for further assessment or possible remediation decisions. To simplify the handling of the calculation complexities appropriate modelling software ought to be made available. (author)

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)

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)

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)

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

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This french congress on the aerosols took place in Paris the 8 and 9 december 1999. It was presented in four main themes: bio-aerosols and filtering; the aerosols metrology; the aerosols in the environment; aerosols physic and applications. Seven papers have been analyzed in INIS data base for their specific interest in nuclear industry. The four papers selected for ETDE cover a larger domain: annular slot samplers in turbulent flow, the air quality monitoring in France, suspension particles characterization in an urban area, application of the remote sensing to the atmospheric pollution. (A.L.B.)

Characterization of aerosols containing fissionable elements using solid-state track recorders

International Nuclear Information System (INIS)

Roberts, J.H.; Kafalenos, V.P.; Yule, T.J.

1976-01-01

An aerosol of U 3 O 3 highly enriched in 235 U was generated with a nebulizer from a suspension of U 3 O 8 powder in distilled water. The aerosol was collected on a membrane filter. Polycarbonate plastic, placed in good contact with the filter, was used to record fission tracks when the package was exposed to known fluences of slow neutrons. Fission-track stars associated with individual particles of U 3 O 8 were observed in the plastic. The fission-track distributions were converted to a particle size distribution for the aerosol. For a log normal distribution the geometric mean and standard deviation can be determined with better than 5% accuracy. This method can be applied to plutonium and other transuranic aerosols. (orig.) [de

Characterisation of aerosols produced by laser cutting; Caracterisation de l'aerosol emis lors d'une decoupe laser

Energy Technology Data Exchange (ETDEWEB)

Fauvel, S.; Pilot, G. [Institut de Radioprotection et de Surete Nucleaire (IRSN), DRU/SERAC, Lab. de Physique et Metrologie des Aerosols, 91 - Gif sur Yvette (France); Dinechin, G. de [Groupe d' Interet Public Groupement d' Etudes et de Recherche pour les Applications Industrielles des Lasers de Puissance, 94 - Arcueil (France)]|[CEA Saclay, Dir. de la Recherche Technologique (DRT/LITEN), 91 - Gif sur Yvette (France); Gosse, X. [Cogema, Dir. de l' Assainissement et des Projets, Maitrise d' Oeuvre Projets, 30 - Marcoule (France); Arnaud, P. [Ligne de Produit Demantelement, SGN, 30 - Bagnols sur Ceze (France)

2007-07-01

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 stuunded 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{sup 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)

Digital high-pass filter deconvolution by means of an infinite impulse response filter

Energy Technology Data Exchange (ETDEWEB)

Födisch, P., E-mail: p.foedisch@hzdr.de [Helmholtz-Zentrum Dresden - Rossendorf, Department of Research Technology, Bautzner Landstr. 400, 01328 Dresden (Germany); Wohsmann, J. [Helmholtz-Zentrum Dresden - Rossendorf, Department of Research Technology, Bautzner Landstr. 400, 01328 Dresden (Germany); Dresden University of Applied Sciences, Faculty of Electrical Engineering, Friedrich-List-Platz 1, 01069 Dresden (Germany); Lange, B. [Helmholtz-Zentrum Dresden - Rossendorf, Department of Research Technology, Bautzner Landstr. 400, 01328 Dresden (Germany); Schönherr, J. [Dresden University of Applied Sciences, Faculty of Electrical Engineering, Friedrich-List-Platz 1, 01069 Dresden (Germany); Enghardt, W. [OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, PF 41, 01307 Dresden (Germany); Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology, Bautzner Landstr. 400, 01328 Dresden (Germany); German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Kaever, P. [Helmholtz-Zentrum Dresden - Rossendorf, Department of Research Technology, Bautzner Landstr. 400, 01328 Dresden (Germany); Dresden University of Applied Sciences, Faculty of Electrical Engineering, Friedrich-List-Platz 1, 01069 Dresden (Germany)

2016-09-11

In the application of semiconductor detectors, the charge-sensitive amplifier is widely used in front-end electronics. The output signal is shaped by a typical exponential decay. Depending on the feedback network, this type of front-end electronics suffers from the ballistic deficit problem, or an increased rate of pulse pile-ups. Moreover, spectroscopy applications require a correction of the pulse-height, while a shortened pulse-width is desirable for high-throughput applications. For both objectives, digital deconvolution of the exponential decay is convenient. With a general method and the signals of our custom charge-sensitive amplifier for cadmium zinc telluride detectors, we show how the transfer function of an amplifier is adapted to an infinite impulse response (IIR) filter. This paper investigates different design methods for an IIR filter in the discrete-time domain and verifies the obtained filter coefficients with respect to the equivalent continuous-time frequency response. Finally, the exponential decay is shaped to a step-like output signal that is exploited by a forward-looking pulse processing.

Carbonaceous Aerosol Characterization during 2016 KOR-US 2016

Science.gov (United States)

Rodriguez, B.; Santos, G. M.; Sanchez, D.; Jeong, D.; Czimczik, C. I.; Kim, S.

2017-12-01

Atmospheric carbonaceous aerosols are a major component of fine particulate matter and assume important roles in Earth's climate and human health. Because atmospheric carbonaceous aerosols exist as a continuum ranging from small, light-scattering organic carbon (OC), to highly-condensed, light-absorbing elemental carbon (EC) they have contrasting effects on interaction with incoming and outgoing radiation, cloud formation, and snow/ice albedo. By strengthening our understanding of the relative contribution and sources of OC and EC we will be able to further describe aerosol formation and mixing at the regional level. To understand the relative anthropogenic and biogenic contributions to carbonaceous aerosol, 12 PM10 aerosols samples were collected on quartz fiber filters at the Mt. Taewha Research Forest in South Korea during the KORUS-AQ 2016 campaign over periods of 24-48 hours with a high-volume air sampler. Analysis of bulk C and N concentrations and absorption properties of filter extracts interspersed with HYSPLIT model results indicated that continental outflow across the Yellow Sea in enriched in bulk nitrogen loading and enhanced bulk absorptive properties of the aerosols. Bulk radiocarbon analysis also indicated enriched values in all samples indicating contamination from a nuclear power plant or the combustion of biomedical waste nearby. Here, we aim to investigate further the chemical characterization of VOCs adsorbed unto the aerosol through TD-GC-TOFMS. With this dataset we aim to determine the relative contribution of anthropogenic and biogenic aerosols by utilizing specific chemical tracers for source apportionment.

Investigations into the design of a filter system for PWR containment venting

International Nuclear Information System (INIS)

Dillmann, H.G.; Wilhelm, J.G.

1991-01-01

The reactors of power stations in the Federal Republic of Germany are being or have already been equipped with systems for containment venting under severe accident conditions. Two different offgas cleaning systems are available. One system, realizing a complete passive filtering concept, consists of a multistage metal fiber filter for coarse particulates and aerosol removal and an additional molecular sieve filter for gaseous iodine retention connected in series. The requirements made with respect to aerosol filtration includes among others the capability of retaining 60 kg of a recondensing aerosol with a 0.5 μm mean geometric mass diameter. BaSO 4 and SnO 2 were used as tracer aerosols in the experiments. All the decontamination factors were > 1,000. Vaporous iodine is removed on molecular sieve filters (zeolite filters) subsequent to airborne particulate filtration. As Ag-zeolites act as catalysts in the H 2 O 2 reaction and thus might give rise to a violent exothermal reaction, the catalytic effect was suppressed by substituting mixed doping for doping solely with silver. The removal efficiencies achieved with Ag-zeolites and zeolites with mixed doping in air-steam mixtures are indicated, and investigations of the catalytic behavior in air-steam-H 2 mixtures are described

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

Science.gov (United States)

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

2009-03-01

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

The Economics of Some Types of Absolute Filters

Energy Technology Data Exchange (ETDEWEB)

Linder, P. J.; Skogulf, H. [Ab Atomenergi, Studsvir (Sweden)

1968-12-15

The cost of air-cleaning filters is determined by the purchase price of the filter and its mean life. If filter changes are not caused by a high level of activity, the increase in pressure drop will make a filter change necessary. In the latter case the dust-holding capacity of the filter determines the interval between changes. A number of different filters have been compared in this respect using atmospheric aerosols and a significant difference in cost has been observed. (author)

Aerosol light absorption and its measurement: A review

International Nuclear Information System (INIS)

Moosmueller, H.; Chakrabarty, R.K.; Arnott, W.P.

2009-01-01

Light absorption by aerosols contributes to solar radiative forcing through absorption of solar radiation and heating of the absorbing aerosol layer. Besides the direct radiative effect, the heating can evaporate clouds and change the atmospheric dynamics. Aerosol light absorption in the atmosphere is dominated by black carbon (BC) with additional, significant contributions from the still poorly understood brown carbon and from mineral dust. Sources of these absorbing aerosols include biomass burning and other combustion processes and dust entrainment. For particles much smaller than the wavelength of incident light, absorption is proportional to the particle volume and mass. Absorption can be calculated with Mie theory for spherical particles and with more complicated numerical methods for other particle shapes. The quantitative measurement of aerosol light absorption is still a challenge. Simple, commonly used filter measurements are prone to measurement artifacts due to particle concentration and modification of particle and filter morphology upon particle deposition, optical interaction of deposited particles and filter medium, and poor angular integration of light scattered by deposited particles. In situ methods measure particle absorption with the particles in their natural suspended state and therefore are not prone to effects related to particle deposition and concentration on filters. Photoacoustic and refractive index-based measurements rely on the heating of particles during light absorption, which, for power-modulated light sources, causes an acoustic signal and modulation of the refractive index in the air surrounding the particles that can be quantified with a microphone and an interferometer, respectively. These methods may suffer from some interference due to light-induced particle evaporation. Laser-induced incandescence also monitors particle heating upon absorption, but heats absorbing particles to much higher temperatures to quantify BC mass

Pressure transients across HEPA filters

International Nuclear Information System (INIS)

Gregory, W.; Reynolds, G.; Ricketts, C.; Smith, P.R.

1977-01-01

Nuclear fuel cycle facilities require ventilation for health and safety reasons. High efficiency particulate air (HEPA) filters are located within ventilation systems to trap radioactive dust released in reprocessing and fabrication operations. Pressure transients within the air cleaning systems may be such that the effectiveness of the filtration system is questioned under certain accident conditions. These pressure transients can result from both natural and man-caused phenomena: atmospheric pressure drop caused by a tornado or explosions and nuclear excursions initiate pressure pulses that could create undesirable conditions across HEPA filters. Tornado depressurization is a relatively slow transient as compared to pressure pulses that result from combustible hydrogen-air mixtures. Experimental investigation of these pressure transients across air cleaning equipment has been undertaken by Los Alamos Scientific Laboratory and New Mexico State University. An experimental apparatus has been constructed to impose pressure pulses across HEPA filters. The experimental equipment is described as well as preliminary results using variable pressurization rates. Two modes of filtration of an aerosol injected upstream of the filter is examined. A laser instrumentation for measuring the aerosol release, during the transient, is described

An automated baseline correction protocol for infrared spectra of atmospheric aerosols collected on polytetrafluoroethylene (Teflon) filters

Science.gov (United States)

Kuzmiakova, Adele; Dillner, Ann M.; Takahama, Satoshi

2016-06-01

A growing body of research on statistical applications for characterization of atmospheric aerosol Fourier transform infrared (FT-IR) samples collected on polytetrafluoroethylene (PTFE) filters (e.g., Russell et al., 2011; Ruthenburg et al., 2014) and a rising interest in analyzing FT-IR samples collected by air quality monitoring networks call for an automated PTFE baseline correction solution. The existing polynomial technique (Takahama et al., 2013) is not scalable to a project with a large number of aerosol samples because it contains many parameters and requires expert intervention. Therefore, the question of how to develop an automated method for baseline correcting hundreds to thousands of ambient aerosol spectra given the variability in both environmental mixture composition and PTFE baselines remains. This study approaches the question by detailing the statistical protocol, which allows for the precise definition of analyte and background subregions, applies nonparametric smoothing splines to reproduce sample-specific PTFE variations, and integrates performance metrics from atmospheric aerosol and blank samples alike in the smoothing parameter selection. Referencing 794 atmospheric aerosol samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011, we start by identifying key FT-IR signal characteristics, such as non-negative absorbance or analyte segment transformation, to capture sample-specific transitions between background and analyte. While referring to qualitative properties of PTFE background, the goal of smoothing splines interpolation is to learn the baseline structure in the background region to predict the baseline structure in the analyte region. We then validate the model by comparing smoothing splines baseline-corrected spectra with uncorrected and polynomial baseline (PB)-corrected equivalents via three statistical applications: (1) clustering analysis, (2) functional group quantification

Application of air ions for bacterial de-colonization in air filters contaminated by aerosolized bacteria

International Nuclear Information System (INIS)

Kim, Yang Seon; Yoon, Ki Young; Park, Jae Hong; Hwang, Jungho

2011-01-01

We aerosolized the Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) bacteria and collected them on membrane filters. Then we generated air ions by applying a high voltage to a carbon fiber tip and applied them to the contaminated filters. The antibacterial efficiency was not significantly affected by the bacteria being Gram-positive or Gram-negative, however, negative ions showed a lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions. With a field emission scanning electron microscope (FE-SEM) images and fluorescence microscopy images using a LIVE/DEAD BacLight Bacterial Viability Kit, electrostatic disruption of the bacteria was found to be the dominant antibacterial effect. - Research Highlights: →This study examined the effects of air ions generated by a carbon fiber ionizer on the inactivation of bioaerosols. →When the ion exposure time and the ion generation concentration were increased, the antibacterial efficiency increased. →The bioaerosols carried a significant number of negative electrical charges. →Negative ions showed lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions.

A model for transient analysis of a multiple-medium confinement filter system

International Nuclear Information System (INIS)

Hyder, M.L.; Ellison, P.G.; Leonard, M.T.; Louie, D.L.Y.; Donbroski, E.L.; Wagner, K.C.

1990-01-01

A computational model is described that calculates the transient behavior of aerosol and vapor (adsorption) filter compartments such as those used in the Savannah River Site (SRS) production reactor confinement system. The principal application of the model is in the analysis of confinement response to hypothetical severe (core melt) accidents. Under these conditions, aerosol and radio-iodine deposition on filter compartments may be substantial. Attendant filter degradation mechanisms are modeled. Sample calculations are included to illustrate model performance. 6 refs., 14 figs., 1 tab

Experiments on high efficiency aerosol filtration

International Nuclear Information System (INIS)

Mazzini, M.; Cuccuru, A.; Kunz, P.

1977-01-01

Research on high efficiency aerosol filtration by the Nuclear Engineering Institute of Pisa University and by CAMEN in collaboration with CNEN is outlined. HEPA filter efficiency was studied as a function of the type and size of the test aerosol, and as a function of flowrate (+-50% of the nominal value), air temperature (up to 70 0 C), relative humidity (up to 100%), and durability in a corrosive atmosphere (up to 140 hours in NaCl mist). In the selected experimental conditions these influences were appreciable but are not sufficient to be significant in industrial HEPA filter applications. Planned future research is outlined: measurement of the efficiency of two HEPA filters in series using a fixed particle size; dependence of the efficiency on air, temperatures up to 300-500 0 C; performance when subject to smoke from burning organic materials (natural rubber, neoprene, miscellaneous plastics). Such studies are relevant to possible accidental fires in a plutonium laboratory

Radiological and toxicological calculations for AY-102 and C-106HEPA filters and pre-filters

International Nuclear Information System (INIS)

Simpson, T.R.; Van Vleet, R.J.

1997-01-01

The high heat content solids in Tank 241-C-106 are to be removed and transferred to Tank 241-AY-102 by sluicing operations, to be authorized under project W-320. Once sluicing operations are underway, the state of these tanks will be transformed from 'unagitated' to 'agitated'. This means that the partition fraction which described the aerosol content of the head space will increase from 1 X 10 - 20 to 1 X 10 -1 . This head space will become much more loaded with suspended material. The nature of this suspended material may change significantly, sluicing may inadvertently bring up radioactive solids which normally would lay under many meters of liquid supernate. It is an enabling assumption that the headspace and filter aerosols in Tank 241-AY-102 are a 90/10 liquid/solid split; there is an unmitigated and mitigated composition. It is an enabling assumption that the sluicing line; the headspace in Tank 241-C-106, and the filters in Tank 241-C-106 contain aerosols which are a 67/33 liquid/solid split; there is an unmitigated and mitigated composition

The continuous analysis of nitrate and ammonium in aerosols by the steam jet aerosol collector (SJAC): extension and validation of the methodology

NARCIS (Netherlands)

Slanina, J.; Brink, ten H.M.; Otjes, R.P.; Even, A.; Jongejan, P.; Khlystov, A.; Waijers-IJpelaan, A.; Hu, M.; Lu, Y.

2001-01-01

Classical methodology based on the application of filters for sampling, followed by extraction and analysis, introduces severe artifacts for semi-volatile compounds like ammonium nitrate. These filter methods do not meet the requirements for the assessment of the impact of aerosols on acidification,

Response of HEPA filters to simulated-accident conditions

International Nuclear Information System (INIS)

Gregory, W.S.; Martin, R.A.; Smith, P.R.; Fenton, D.E.

1982-01-01

High-efficiency particulate air (HEPA) filters have been subjected to simulated accident conditions to determine their response to abnormal operating events. Both domestic and European standard and high-capacity filters have been evaluated to determine their response to simulated fire, explosion, and tornado conditions. The HEPA filter structural limitations for tornado and explosive loadings are discussed. In addition, filtration efficiencies during these accident conditions are reported for the first time. Our data indicate efficiencies between 80% and 90% for shock loadings below the structural limit level. We describe two types of testing for ineffective filtration - clean filters exposed to pulse-entrained aerosol and dirty filters exposed to tornado and shock pulses. Efficiency and material loss data are described. Also, the resonse of standard HEPA filters to simulated fire conditions is presented. We describe a unique method of measuring accumulated combustion products on the filter. Additionally, data relating to pressure drop vs accumulated mass during plugging are reported for simulated combustion aerosols. The effects of concentration and moisture levels on filter plugging were evaluated. We are obtaining all of the above data so that mathematical models can be developed for fire, explosion, and tornado accident analysis computer codes. These computer codes can be used to assess the response of nuclear air cleaning systems to accident conditions

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

Continuous air monitor for alpha-emitting aerosol particles

International Nuclear Information System (INIS)

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

1991-01-01

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

Study on generation and granulometry of a standard aerosol of CINa for use in determinations of filtration efficiency of absolute filters

International Nuclear Information System (INIS)

Milla, E.

1978-01-01

This work has as objective the study of the conditions of generation and granulometry of an aerosol generated by atomizing with compressed a i r a solution of CINa in water in order to obtain particles, CINa cubes. The droplets of the spray formed are dried in a stream of air, acting as a carrier, inside the pipe of a bank of test filters. The granulometric analysis has been carried out by sampling in the gaseous phase. A dispersion photometer was used that yields the size spectrum of particles. The variables concerned in generation, whose influence on aerosol granulometry were analyzed are: characteristic diameter of atomizer unit, pressure of compressed air of generation, concentration of saline solution, temperature of air carrier, length of bank pipe, sampling position across a section, length of sampling duct and ratio between speeds in pipe and duct. (Author) 50 refs

Data assimilation of CALIPSO aerosol observations

Directory of Open Access Journals (Sweden)

T. T. Sekiyama

2010-01-01

Full Text Available We have developed an advanced data assimilation system for a global aerosol model with a four-dimensional ensemble Kalman filter in which the Level 1B data from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO were successfully assimilated for the first time, to the best of the authors' knowledge. A one-month data assimilation cycle experiment for dust, sulfate, and sea-salt aerosols was performed in May 2007. The results were validated via two independent observations: 1 the ground-based lidar network in East Asia, managed by the National Institute for Environmental Studies of Japan, and 2 weather reports of aeolian dust events in Japan. Detailed four-dimensional structures of aerosol outflows from source regions over oceans and continents for various particle types and sizes were well reproduced. The intensity of dust emission at each grid point was also corrected by this data assimilation system. These results are valuable for the comprehensive analysis of aerosol behavior as well as aerosol forecasting.

First Study Of HEPA Filter Prototype Performance To Control The Airborne Pollution

International Nuclear Information System (INIS)

Soetomo; Suwarno

2000-01-01

This paper will report the efficiency test result of the filtration tool prototype of High Efficiency Particulate Air (HEPA filter) for low temperature, to control the airborne pollution of aerosol particle of solid and liquid. The prototype design of HEPA filter was based on the characteristic data of filter material (fibrous diameter, density, filter thickness), flow rate of air and first pressure drop. From the result of laboratory scale test, using DOP/PSL aerosol with 0,3 mum diameter and the flow rate of 3,78 m exp.3/min, was obtained filtration efficiency revolve between 89,90 and 99,94 % for the filter prototype of A, B, C, and D. the efficiency estimation of theory with filtration programme and the experiment was different amount 1 %. The value of the prototype efficiency of D filter was not far different with AAF-USA filter and its price is cheaper 30 % than the price of AAF-USA filter

Estimating back to front ratio of wire screen for measurement of thoron decay products

International Nuclear Information System (INIS)

Koli, Amruta; Khandare, Pallavi; Joshi, Manish; Mariam; Khan, Arshad; Sapra, B.K.

2016-01-01

Wire screens are widely used for measuring the fine fraction of radon/thoron decay products. Their capture efficiencies are generally defined at low aerosol concentration conditions as well as at low sampling flow rates. Effect of changes in sampling flow rate and aerosol concentration on wire screen capture efficiencies and counting correction factor has been studied in this work. Controlled experiments have been conducted using two different mesh sizes at two different aerosol concentration conditions. Experimental results were compared with the existing theories for capture efficiencies of wire screens given by Cheng and Yeh (1980) and Alonso et al. (2001); and semi empirical relation for the front to total ratio given by Solomon and Ren (1992). Theoretical predictions have been found to be relatively close to the experimental findings for moderate aerosol conditions but disagreement was observed in case of high aerosol concentration. The possible reasons for these differences have been discussed in this work. - Highlights: • Effect of Fiber Reynolds number on capture efficiency and back to front ratio of wire screen. • Experiments with Thoron decay products at moderate and elevated aerosol concentrations. • Comparison with theoretical estimates. • Fair agreement observed for moderate aerosol concentration.

Aerosol behavior in the reactor containment building during severe accident

International Nuclear Information System (INIS)

Berthion, Y.; Lhiaubet, G.; Gauvain, J.

1984-07-01

Thermohydraulic behavior inside a PWR containment during severe accident depends on decay heat transferred to the sump water by aerosol gravitational settling and deposition. Conversely, aerosol behavior depends on thermal hydraulic conditions, especially atmosphere moisture for soluble aerosol GsI, and CsOH. Therefore, a small iterative procedure between thermo-hydraulic and aerosol calculations has been performed in order to evaluate the importance of this coupling between the two phenomena. In this paper, it is shown that with this procedure and using our codes JERICHO, RICOCHET and AEROSOLS/B1, the steam condensation on aerosols is an important phenomenon for a correct estimation of the attenuation factor of the suspended mass of aerosols in the airborne of the containment. Then, we have a more realistic assessment of the source term released by the containment

The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

Energy Technology Data Exchange (ETDEWEB)

Bartlett, W.T.; Walker, B.A. [Environmental Evaluation Group, Albuquerque, NM (United States)

1997-08-01

Waste Isolation Pilot Plant (WIPP) alpha continuous air monitor (CAM) performance was evaluated to determine if CAMs could detect accidental releases of transuranic radioactivity from the underground repository. Anomalous alpha spectra and poor background subtraction were observed and attributed to salt deposits on the CAM sampling filters. Microscopic examination of salt laden sampling filters revealed that aerosol particles were forming dendritic structures on the surface of the sampling filters. Alpha CAM detection efficiency decreased exponentially as salt deposits increased on the sampling filters, suggesting that sampling-filter salt was performing like a fibrous filter rather than a membrane filter. Aerosol particles appeared to penetrate the sampling-filter salt deposits and alpha particle energy was reduced. These findings indicate that alpha CAMs may not be able to detect acute releases of radioactivity, and consequently CAMs are not used as part of the WIPP dynamic confinement system. 12 refs., 12 figs., 1 tab.

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

Continual monitoring of radon decay products concentration in indoor and outdoor air

International Nuclear Information System (INIS)

Petruf, P.; Holy, K.; Stanys, T.

1998-01-01

The goal of this work was the development of the method and construction and testing of measurement device for continual monitoring of radon daughters concentrations in the indoor and outdoor environment with regard to make possible to determine very low activities in the outdoor air (below % Bq/m 3 ). In this method air sample is drawn through the appropriate filter material. Radon and thoron daughters both attached and unattached on aerosols particles are collected on the filter surface and then the filter activity is counted. The silicon surface barrier detector with the active area of 200 mm 2 in monitor was used. The Millipore AW19-type filter was chosen and sampling rate of 30 l/min for collecting of the air samples. The determination of the individual activity concentrations in three-count method is based on the solution of the simultaneous equations describing the number of atoms of measured nuclides on the filter during and after sampling. The monitor was tested in three different environments (the average values of the activity concentrations of radon and its decay products in Bq/m 3 are given): in the basement of the building: 61.4 ± 5.0 of 222 Rn, 29.5 ± 2.8 of 218 Po, 14.1 ± 1.8 of 214 Pb and 12.1 ± 1.6 of 214 Bi; in the room on the second floor of the same building:22.2 ± 7.9 of 222 Rn, 7.3 ± 2.8 of 218 Po, 4.6 ± 1.9 of 214 Pb and 2.6 ± 1.2 of 214 Bi ; in the outdoor air in front of the building: 4.1 ± 2.7 of 222 Rn, 2.3 ± 0.9 of 218 Po, 1.5 ± 0.8 of 214 Pb and 1.4 ± 0.6 of 214 Bi. The results show a good agreement with expectations of the activity concentrations in three different environments. The monitor enables to determine low activity concentrations in the outdoor with an acceptable precision during one hour counting. The monitor can be used for the research of the correlation between the atmospheric stability and activity concentrations of radon decay products

Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

Directory of Open Access Journals (Sweden)

D. B. Collins

2014-11-01

Full Text Available Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA must be under-pinned by a physically and chemically accurate representation of the bubble-mediated production of nascent SSA particles. Bubble bursting is sensitive to the physico-chemical properties of seawater. For a sample of seawater, any important differences in the SSA production mechanism are projected into the composition of the aerosol particles produced. Using direct chemical measurements of SSA at the single-particle level, this study presents an intercomparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits", a pulsed plunging-waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than those produced by sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic-enriched particles and a different size-resolved elemental composition, especially in the 0.8–2 μm dry diameter range. Interestingly, chemical differences between the methods only emerged when the particles were chemically analyzed at the single-particle level as a function of size; averaging the elemental composition of all particles across all sizes masked the differences between the SSA samples. When dried, SSA generated by the sintered glass filters had the highest fraction of particles with spherical morphology compared to the more cubic structure expected for pure NaCl particles produced when the particle contains relatively little organic carbon. In addition to an intercomparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method on SSA composition was under-taken. In organic

Characteristics, sources and evolution of fine aerosol (PM1) at urban, coastal and forest background sites in Lithuania

NARCIS (Netherlands)

Masalaite, A.; Holzinger, R.; Remeikis, V.; Roeckmann, Thomas; Dusek, U.

The chemical and isotopic composition of organic aerosol (OA) samples collected on PM1 filters was determined as a function of desorption temperature to investigate the main sources of organic carbon and the effects of photochemical processing on atmospheric aerosol. The filter samples were

Radiological and toxicological calculations for AY-102 and C-106HEPA filters and pre-filters

Energy Technology Data Exchange (ETDEWEB)

Simpson, T.R.; Van Vleet, R.J.

1997-07-01

The high heat content solids in Tank 241-C-106 are to be removed and transferred to Tank 241-AY-102 by sluicing operations, to be authorized under project W-320. Once sluicing operations are underway, the state of these tanks will be transformed from `unagitated` to `agitated`. This means that the partition fraction which described the aerosol content of the head space will increase from 1 X 10{sup - 20} to 1 X 10{sup -1}. This head space will become much more loaded with suspended material. The nature of this suspended material may change significantly, sluicing may inadvertently bring up radioactive solids which normally would lay under many meters of liquid supernate. It is an enabling assumption that the headspace and filter aerosols in Tank 241-AY-102 are a 90/10 liquid/solid split; there is an unmitigated and mitigated composition. It is an enabling assumption that the sluicing line; the headspace in Tank 241-C-106, and the filters in Tank 241-C-106 contain aerosols which are a 67/33 liquid/solid split; there is an unmitigated and mitigated composition.

A contribution to the study of atmospheric aerosols in urban, marine and oceanic areas

International Nuclear Information System (INIS)

Butor, Jean-Francois

1980-01-01

A study of atmospheric aerosols, especially marine aerosols, was carried out, using impactors and nuclepore filters in association with electron microscopy techniques. The performances of the experimental device were first determined carefully and a generator of monodisperse aerosols was built at the laboratory in order to measure the efficiency of the filters used. It was demonstrated that the chief atmospheric particulate constituents could be determined by electron microscopy. The particle-size distribution of oceanic aerosols was next studied on the basis of the results of three measurement campaigns carried out in the Atlantic ocean. In Brest, where urban aerosols more or less affected by the meteorological conditions can be found superimposed to marine aerosols, an assessment was made of the effects of moderate anthropogeneous pollution on marine aerosols as measured in the Atlantic ocean. Two cases of marine aerosol disturbance, the former by an accidental marine pollution, the latter linked to a natural local phenomenon are related and a model of the marine aerosol in the Northern Atlantic ocean is proposed which takes into account the mean particle size spectra, the characteristic parameters of its three-modal distribution and the qualitative analysis of particles. (author) [fr

The proton induced X-ray emission (PIXE) for the quantitative analysis of elements in thin samples, in surface layers of thick samples, and in aerosol filters

International Nuclear Information System (INIS)

Waetjen, U.

1983-01-01

The PIXE analysis method for the determination of elements in thick samples was investigated. The text of the present thesis is arranged under the following headings: physical fundamentals and measuring equipment, quantitative analysis of thin samples, matrix effects at the PIXE analysis of thick samples, matrix correction methods, analysis of 'infinite thick' model substances, PIXE analysis of aerosol filters. (GSCH)

Application of difference filter to Feynman-α analysis

International Nuclear Information System (INIS)

Mouri, Tomoaki; Ohtani, Nobuo

1997-11-01

The Feynman-α method has been developed for monitoring sub-criticality in nuclear fuel facilities. It is difficult to apply the Feynman-α method which estimates statistical variation of the number of neutron counts per unit time, to the system in transient condition such that the averaged neutron flux varies with time. In the application of Feynman-α method to such system, it is suggested to remove the averaged variation of neutron flux from neutron count data by the use of the difference filter. In this study, we applied the difference filter to reactor noise data at sub-criticality near to criticality, where the prompt decay constant was difficult to estimate due to the large effect of delayed neutron. With the difference filter, accurate prompt decay constants for effective multiplication factors from 0.999 to 0.994 were obtained by Feynman-α method. It was cleared that the difference filter is effective to estimate accurate prompt decay constant, so that there is the prospect to be able to apply Feynman-α method having the difference filter to the system in the transient condition. (author)

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

The measurement of the radioactive aerosol diameter by position sensitive detectors, 3

International Nuclear Information System (INIS)

Murakami, Hiroyuki; Nakamoto, Atsushi; Kanamori, Masashi; Seki, Akio.

1981-10-01

The measurement of the diameter of radioactive aerosol, in particular plutonium aerosol, is very important for the internal dose estimation. Determination of the diameter of radioactive aerosol is performed by using the position sensitive detectors. Position sensitive semiconductor detectors and Scintillation detectors with IIT tube are used as the position sensitive detector. The filter paper with the radioactive aerosols is contacted to the PSD which is connected to the data processor so that the diameter of the aerosol is calculated from the measured radioactivity. (author)

Nuclear track radiography of 'hot' aerosol particles

CERN Document Server

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

1999-01-01

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

Nuclear track radiography of 'hot' aerosol particles

International Nuclear Information System (INIS)

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

1999-01-01

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

Particulate silica test agents for hepa filters

International Nuclear Information System (INIS)

Bauman, A.J.

1987-01-01

The authors developed a solid test aerosol (Dri-Test) and a versatile portable delivery system for it. The aerosol is based on thermal silica, modified chemically to make it surface-hydrophobic and fluorescent under UV illumination. The fluorescent tag enables one to identify tested filters. Primary particles are 7 nm in diameter, spherical, and of density 2.20 gm-cm/sup -3/ bulk aerosol powder has a density of 0.048 gm-cm/sup -3/. Tests by means of laser particle counters, TSI Nucleation counters and California Measurements Quartz Microbalance mass analyzer show that the delivered aerosol has a bimodal size distribution with peaks near 80 and 100 nm. An estimated 40-50% of the aerosol has a size below the limits of detectability by laser (Las-X) counters, i.e. 50 nm. The surfachydrophobic aerosol is unaffected by ambient humidity and unlike hydrophilic silicas is innocuous to health

Testing the count rate performance of the scintillation camera by exponential attenuation: Decaying source; Multiple filters

International Nuclear Information System (INIS)

Adams, R.; Mena, I.

1988-01-01

An algorithm and two fortrAN programs have been developed to evaluate the count rate performance of scintillation cameras from count rates reduced exponentially, either by a decaying source or by filtration. The first method is used with short-lived radionuclides such as 191 /sup m/Ir or 191 /sup m/Au. The second implements a National Electrical Manufacturers' Association (NEMA) protocol in which the count rate from a source of 191 /sup m/Tc is attenuated by a varying number of copper filters stacked over it. The count rate at each data point is corrected for deadtime loss after assigning an arbitrary deadtime (tau). A second-order polynomial equation is fitted to the logarithms of net count rate values: ln(R) = A+BT+CT 2 where R is the net corrected count rate (cps), and T is the elapsed time (or the filter thickness in the NEMA method). Depending on C, tau is incremented or decremented iteratively, and the count rate corrections and curve fittings are repeated until C approaches zero, indicating a correct value of the deadtime (tau). The program then plots the measured count rate versus the corrected count rate values

Long-term measurement of aerosol chemical composition in Athens, Greece.

Science.gov (United States)

Paraskevopoulou, Despina; Liakakou, Eleni; Theodosi, Christina; Gerasopoulos, Evangelos; Mihalopoulos, Nikolaos

2014-05-01

The collection of our samples was conducted for a period of five years (2008 - 2013) in Athens, Greece. The site is situated at the premises of the National Observatory of Athens on Penteli Hill, northeast Athens suburbs, and is considered an urban background station. The aim of our study was a first long-term estimation of the chemical mass closure of aerosol. For the purposes of the study, we applied three filter samplers during the sampling period: two Partisol FRM Model 2000 air samplers (one of them collecting PM10 and the other PM2.5 fractions of aerosol) and one Dichotomous Partisol auto-sampler (with PM2.5 and PM2.5-10 inlet). Aerosols were collected on Whatman QM-A quartz fiber filters and the mass of the collected samples was estimated by weighing the pre-combusted filters before and after sampling, under controlled conditions, using a microbalance. All quartz filters were analysed for organic (OC) and elemental carbon (EC) by a thermal - optical transmission technique. The concentration of water soluble organic carbon (WSOC) was defined for each filter using a total organic carbon analyzer, while the content in main water soluble ions (Cl-, Br-, NO-3, SO4-2, PO4-3, C2O4-2, NH4+, K+, Na+, Mg+2, Ca+2) was determined by ion chromatography. Additionally the filters were analyzed for trace metals by inductively coupled plasma optical emission spectrometry (ICP-OES). Aerosol chemical mass closure calculations were conducted for the PM2.5 fraction. The area of Athens is characterized by aged aerosol that can originate from the marine boundary layer, the European mainland and occasionally from North African desert areas. The contribution of dust and particulate organic matter on PM levels was estimated taking into consideration the location of the sampling site, while identification and evaluation of sources was performed. Additionally, non-sea salt concentrations of the main ions were estimated to complete the chemical closure in the extended area. According to

Design and full scale test of a sand bed filter

International Nuclear Information System (INIS)

Kaercher, M.

1991-01-01

All French pressurized water reactor plants are equipped with a containment venting system. this system is designed and implemented by Electricite de France with the technical support of safety authorities (Institute of Protection and Nuclear Safety of Atomic Energy Commission). This paper covers the following items: main assumptions, sizing and design requirements; basic design of the filter resulting from PITEAS R and D program carried out between 1983 and 1989 at Cadarache nuclear center; full scale tests performed in 1990 on FUCHIA loop at Cadarache including description of the loop using plasma torches to generate CsOH aerosols in a steam - air flow, and preliminary results concerning thermohydraulic and thermic behavior under residual power simulated filtration efficiency with CsOH aerosols and iodine; complementary design, including hydrogen risk during condensation period, radiological shieldings of the filter, and heat removal after the filter closure; and conclusion on the validation of the filter

Evaluation of the filtration performance of NIOSH-approved N95 filtering facepiece respirators by photometric and number-based test methods.

Science.gov (United States)

Rengasamy, Samy; Miller, Adam; Eimer, Benjamin C

2011-01-01

N95 particulate filtering facepiece respirators are certified by measuring penetration levels photometrically with a presumed severe case test method using charge neutralized NaCl aerosols at 85 L/min. However, penetration values obtained by photometric methods have not been compared with count-based methods using contemporary respirators composed of electrostatic filter media and challenged with both generated and ambient aerosols. To better understand the effects of key test parameters (e.g., particle charge, detection method), initial penetration levels for five N95 model filtering facepiece respirators were measured using NaCl aerosols with the aerosol challenge and test equipment employed in the NIOSH respirator certification method (photometric) and compared with an ultrafine condensation particle counter method (count based) for the same NaCl aerosols as well as for ambient room air particles. Penetrations using the NIOSH test method were several-fold less than the penetrations obtained by the ultrafine condensation particle counter for NaCl aerosols as well as for room particles indicating that penetration measurement based on particle counting offers a more difficult challenge than the photometric method, which lacks sensitivity for particles photometric method may not be a more challenging aerosol test method. Filter penetrations can vary among workplaces with different particle size distributions, which suggests the need for the development of new or revised "more challenging" aerosol test methods for NIOSH certification of respirators.

Choice of Method of Collection and Measurement for an Aerosol Monitor with Filter; Choix du Mode de Collection et de Mesure pour un Moniteur d'Aerosols a Filtre

Energy Technology Data Exchange (ETDEWEB)

Lafont-Rapnouil, M. [Compagnie Francaise Thomson Houston-Hotchkiss Brandt, Chatou (France)

1967-12-15

In radioprotection it is more important to have continuous information about the total activity inhaled (MPC over eight hours) than of the specific activity. The author compares simple formulae expressing the signal as a function of the method of sampling (fixed or mobile filter) and discusses the physical meaning of the signal. Examination of the essential feature of an alarm device for preventive purposes (authorization of access) or for continuous monitoring of the atmosphere suggests that a useful solution to the basic problems posed by this type of instrument would be to employ a fixed filter whose activity is measured during sampling. This procedure also has the advantages of simplicity, satisfactory detection efficiency, speed of response, homogeneity of the deposit in regard to the detector and convenient operation. Use of a fixed filter does not exclude its automatic replacement by a step-by-step feed system which can itself be linked to the triggering of the alarm. A brief description is given of an embodiment of sampling heads meeting the above criteria and of the associated filter supports. These heads can be fitted with different detectors (alpha, beta, mixed: Geiger-Mueller counters, scintillators or semi-conductors) and allow easy changing of the filter. The choice of these principles does not alter the fact that there are other, very complex, aspects to the question of the overall validity of the sampling process but it does provide simple solutions to routine problems relating to aerosol radioactivity. (author) [French] En radioprotection, ce qu'il importe de connaitre en permanence est, plus que l'activite specifique, l'activite globale inhalee (CMA/8 h). On compare les formules simples exprimant le signal en fonction du mode d'echantillonnage (filtre fixe ou mobile), et la signification physique de ce signal. L'examen des differents imperatifs pour un appareil d'alarme utilise, soit en mesure preventive (autorisation d'acces), soit en

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

Study of loading/air back-pulse cleaning cycles on the performance of ceramic membrane filters

International Nuclear Information System (INIS)

Waggoner, Charles; Alderman, Steven; Parsons, Michael; Hogoncamp, Kristina; Alderman, Steven

2007-01-01

Available in abstract form only. Full text of publication follows: The most commonly identified threats to conventional glass fiber HEPA filter performance are moisture and rapid blinding of filters by smoke. Regenerable filter media composed of ceramics or sintered metal can be utilized as pre-filters to protect the more vulnerable glass fiber HEPA filters in the event of upset conditions. Additionally, used in a pre-filtering application, the use of these regenerable filters can potentially extend the lifetime of conventional units. A series of tests have been conducted using CeraMem ceramic membrane filters in an effort to evaluate their performance after repeated loading and air back pulse cleaning. This was done in an effort to access filter performance after repeated loading/cleaning cycles. The filters were loaded using a solid potassium chloride aerosol challenge. The filters were evaluated for pressure drop and filtering efficiency changes from one cleaning cycle to the next. Additionally, the particle size distribution of the aerosol penetrating the filters was measured. (authors)

ASME AG-1 Section FC Qualified HEPA Filters; a Particle Loading Comparison - 13435

International Nuclear Information System (INIS)

Stillo, Andrew; Ricketts, Craig I.

2013-01-01

High Efficiency Particulate Air (HEPA) Filters used to protect personnel, the public and the environment from airborne radioactive materials are designed, manufactured and qualified in accordance with ASME AG-1 Code section FC (HEPA Filters) [1]. The qualification process requires that filters manufactured in accordance with this ASME AG-1 code section must meet several performance requirements. These requirements include performance specifications for resistance to airflow, aerosol penetration, resistance to rough handling, resistance to pressure (includes high humidity and water droplet exposure), resistance to heated air, spot flame resistance and a visual/dimensional inspection. None of these requirements evaluate the particle loading capacity of a HEPA filter design. Concerns, over the particle loading capacity, of the different designs included within the ASME AG-1 section FC code[1], have been voiced in the recent past. Additionally, the ability of a filter to maintain its integrity, if subjected to severe operating conditions such as elevated relative humidity, fog conditions or elevated temperature, after loading in use over long service intervals is also a major concern. Although currently qualified HEPA filter media are likely to have similar loading characteristics when evaluated independently, filter pleat geometry can have a significant impact on the in-situ particle loading capacity of filter packs. Aerosol particle characteristics, such as size and composition, may also have a significant impact on filter loading capacity. Test results comparing filter loading capacities for three different aerosol particles and three different filter pack configurations are reviewed. The information presented represents an empirical performance comparison among the filter designs tested. The results may serve as a basis for further discussion toward the possible development of a particle loading test to be included in the qualification requirements of ASME AG-1

ASME AG-1 Section FC Qualified HEPA Filters; a Particle Loading Comparison - 13435

Energy Technology Data Exchange (ETDEWEB)

Stillo, Andrew [Camfil Farr, 1 North Corporate Drive, Riverdale, NJ 07457 (United States); Ricketts, Craig I. [New Mexico State University, Department of Engineering Technology and Surveying Engineering, P.O. Box 30001 MSC 3566, Las Cruces, NM 88003-8001 (United States)

2013-07-01

High Efficiency Particulate Air (HEPA) Filters used to protect personnel, the public and the environment from airborne radioactive materials are designed, manufactured and qualified in accordance with ASME AG-1 Code section FC (HEPA Filters) [1]. The qualification process requires that filters manufactured in accordance with this ASME AG-1 code section must meet several performance requirements. These requirements include performance specifications for resistance to airflow, aerosol penetration, resistance to rough handling, resistance to pressure (includes high humidity and water droplet exposure), resistance to heated air, spot flame resistance and a visual/dimensional inspection. None of these requirements evaluate the particle loading capacity of a HEPA filter design. Concerns, over the particle loading capacity, of the different designs included within the ASME AG-1 section FC code[1], have been voiced in the recent past. Additionally, the ability of a filter to maintain its integrity, if subjected to severe operating conditions such as elevated relative humidity, fog conditions or elevated temperature, after loading in use over long service intervals is also a major concern. Although currently qualified HEPA filter media are likely to have similar loading characteristics when evaluated independently, filter pleat geometry can have a significant impact on the in-situ particle loading capacity of filter packs. Aerosol particle characteristics, such as size and composition, may also have a significant impact on filter loading capacity. Test results comparing filter loading capacities for three different aerosol particles and three different filter pack configurations are reviewed. The information presented represents an empirical performance comparison among the filter designs tested. The results may serve as a basis for further discussion toward the possible development of a particle loading test to be included in the qualification requirements of ASME AG-1

Study of aerosol behaviour in an acoustic field

International Nuclear Information System (INIS)

Malherbe, C.

1988-01-01

The average size of an aerosol submitted to acoustic waves is increased. This results from coagulation of the finer particles on the larger ones. An experimental apparatus was developed in order to control the evolution of aerosol distribution in an acoustic field. Important deposition on the walls of the agglomeration chamber was observed as a consequence of the acoustically induced turbulent flow. Consequently, we experimentally evaluated the turbulent properties of the system. A granular bed submitted to an acoustic field and set downstream an agglomerator constitutes an almost absolute filter for an usually penetrating aerosol [fr

Development of membrane filters with nanostructured porous layer by coating of metal nanoparticles sintered onto a micro-filter

International Nuclear Information System (INIS)

Park, Seok Joo; Park, Young Ok; Lee, Dong Geun; Ryu, Jeong In

2008-01-01

The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 KPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%

Multi-compartment Aerosol Transport Model

Energy Technology Data Exchange (ETDEWEB)

Hubbard, Joshua Allen; Santarpia, Joshua; Brotherton, Christopher M.; Omana, Michael Alexis; Rivera, Danielle; Lucero, Gabriel Anthony

2017-06-01

A simple aerosol transport model was developed for a multi-compartmented cleanroom. Each compartment was treated as a well-mixed volume with ventilating supply and return air. Gravitational settling, intercompartment transport, and leakage of exterior air into the system were included in the model. A set of first order, coupled, ordinary differential equations was derived from the conservation equations of aerosol mass and air mass. The system of ODEs was then solved in MATLAB using pre-existing numerical methods. The model was verified against cases of (1) constant inlet-duct concentration, and (2) exponentially decaying inlet-duct concentration. Numerical methods resulted in normalized error of less than 10 -9 when model solutions were compared to analytical solutions. The model was validated against experimental measurements from a single field test and showed good agreement in the shape and magnitude of the aerosol concentration profile with time.

Desorption atmospheric pressure photoionization high-resolution mass spectrometry: a complementary approach for the chemical analysis of atmospheric aerosols.

Science.gov (United States)

Parshintsev, Jevgeni; Vaikkinen, Anu; Lipponen, Katriina; Vrkoslav, Vladimir; Cvačka, Josef; Kostiainen, Risto; Kotiaho, Tapio; Hartonen, Kari; Riekkola, Marja-Liisa; Kauppila, Tiina J

2015-07-15

On-line chemical characterization methods of atmospheric aerosols are essential to increase our understanding of physicochemical processes in the atmosphere, and to study biosphere-atmosphere interactions. Several techniques, including aerosol mass spectrometry, are nowadays available, but they all suffer from some disadvantages. In this research, desorption atmospheric pressure photoionization high-resolution (Orbitrap) mass spectrometry (DAPPI-HRMS) is introduced as a complementary technique for the fast analysis of aerosol chemical composition without the need for sample preparation. Atmospheric aerosols from city air were collected on a filter, desorbed in a DAPPI source with a hot stream of toluene and nitrogen, and ionized using a vacuum ultraviolet lamp at atmospheric pressure. To study the applicability of the technique for ambient aerosol analysis, several samples were collected onto filters and analyzed, with the focus being on selected organic acids. To compare the DAPPI-HRMS data with results obtained by an established method, each filter sample was divided into two equal parts, and the second half of the filter was extracted and analyzed by liquid chromatography/mass spectrometry (LC/MS). The DAPPI results agreed with the measured aerosol particle number. In addition to the targeted acids, the LC/MS and DAPPI-HRMS methods were found to detect different compounds, thus providing complementary information about the aerosol samples. DAPPI-HRMS showed several important oxidation products of terpenes, and numerous compounds were tentatively identified. Thanks to the soft ionization, high mass resolution, fast analysis, simplicity and on-line applicability, the proposed methodology has high potential in the field of atmospheric research. Copyright © 2015 John Wiley & Sons, Ltd.

Calculation Of Aerosol Transport Efficiency For The Airborne Radioiodine Monitoring System - ''RIS125''

International Nuclear Information System (INIS)

Kravchik, T.; Levinson, L.; Mazor, Y.; Dolev, E.; German, U.

1999-01-01

Radioactive iodine is a typical fission product in nuclear power reactors. Of the many iodine isotopes that can be generated in nuclear reactors only four are considered as radiobiological significant. These are: 125 1 (T 1/2 =60 days), '1 31 I (T 1/2 =8d), 133 I (T 1/2 =21h) and I35 I (T 1/2 7h). The chemical forms that have been identified in heavy water reactors are I 2 (elemental), organic iodides (CH 3 I), Inorganic iodides (HOI, HI) and LiI. Radioiodine is, generally, released as a gas but can be adsorbed on air particulates to form radioiodine contained aerosols. Therefore. its monitoring has to include both gas and aerosol sampling. A new monitoring system, RIS (Radioactive iodine Sampler), has been developed at the NRCN to monitor radioactive iodine (gas and aerosol) on-line in workplaces. This system samples radioiodine at a 60 L/min rate through a transport line connected to a filter holder. The filter consists of a cartridge containing activated charcoal with TEDA for iodine gas adsorption with a membrane for aerosols' retention in from of it. The radioiodine filter cartridge (F and J product code: TE2C) has a diameter of 2 1/4 inch and height of 1 inch . The gas adsorbent is coconut shell carbon type activated charcoal with 5% (by weight) TEDA impregnation and has 30x50 mesh size. This paper presents the aerosols' sampling characteristics of the RIS system including their transport in the sampling line and filter holder. The adsorption of iodine gas on the transport system components is negligible

Performance of 1000- and 1800- cfm HEPA filters on long exposure to low atmospheric dust loadings, II

International Nuclear Information System (INIS)

First, M.W.; Rudnick, S.N.

1981-01-01

Comparative tests were made to evaluate the performance characteristics of American- and European-design HEPA filters when exposed, for a number of years, to aerosols characteristic of nuclear and biohazard service. Although some of the European-design filters were operated at their rated airflow capacity of 1800 cfm, some were downrated to 1000 cfm to determine if their service life could be more than tripled compared to conventional 1000-cfm Americal-design HEPA filters, as filter theory predicts. Initial results indicate, however, that for the ambient aerosol used in this study, a European-design filter has a service life of only 1.6 times greater than an American-design filter when both operate at 1000 cfm. Further tests are in progress to verify this result

Emergency Response Proficiency Test for Japanese Laboratories: Determination of Selected Radionuclides in Water, Soil, Vegetation and Aerosol Filters

International Nuclear Information System (INIS)

2013-01-01

Reliable determination of natural and artificial radionuclides in environmental samples is necessary for compliance with radiation protection and environmental regulations. The IAEA assists Member State laboratories in maintaining and improving their readiness in this regard by producing reference materials, by developing standardized analytical methods, and by conducting interlaboratory comparisons and proficiency tests as tools for quality control. To fulfil this obligation and ensure a reliable, rapid and consistent worldwide response, the IAEA Terrestrial Environment Laboratory in Seibersdorf, Austria, organizes interlaboratory comparisons and proficiency tests. In addition, the IAEA coordinates the worldwide network of Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA). After the accident at the Fukushima Daiichi nuclear power plant in March 2011, Japan requested the IAEA to organize an emergency response proficiency test for Japanese laboratories with the aim of assessing their capacity to rapidly and accurately measure radionuclides in environmental samples. The IAEA responded to the request by assembling a special sample set covering the main environmental samples and radionuclides of interest in the case of a nuclear emergency situation. Water, soil, vegetation and aerosol filter samples were made available to Japanese laboratories for analysis by gamma ray spectrometry. This report presents the results of the IAEA-TEL-2011-08 emergency response proficiency test for Japanese laboratories on the determination of selected radionuclides in water, soil, vegetation and aerosol filters. The report includes descriptions of the methodologies and data evaluation approach used, as well as summary evaluations of each radionuclide and individual evaluation reports of each laboratory. This proficiency test was designed to identify analytical problems and to support Member State laboratories in their efforts to improve the quality of

Number concentrations of solid particles from the spinning top aerosol generator

International Nuclear Information System (INIS)

Mitchell, J.P.

1983-02-01

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

Dissemination of aerosol and splatter during ultrasonic scaling: A pilot study

Directory of Open Access Journals (Sweden)

H.R. Veena

2015-05-01

Full Text Available Summary: Context: Routine dental procedures produce aerosol and splatter, which pose a potential risk to the clinician and dental personnel, as well as the immunocompromised patient. Reports indicate that the ultrasonic scaler is the greatest producer of aerosol and splatter. Aims: The study aimed to evaluate the contamination distance, contamination amount and contamination duration of aerosol produced during ultrasonic scaling. Methods and materials: The study was performed on a mannequin fitted with phantom jaws on a dental chair. Mock scaling was done for 15 min using an auto-tuned magnetostrictive ultrasonic scaler with the simultaneous use of a low volume saliva ejector. An ultrafiltrate-containing fluorescent dye was used in the reservoir supplying the scaler unit. Filter paper discs were placed in different positions and distances in the operatory. Immediately following scaling, the filter paper discs were replaced with new ones. This was done every 30 min for a total duration of 90 min. Results: Maximum contamination was found on the right arm of the operator and left arm of the assistant. Contamination was also found on the head, chest and inner surface of the face mask of the operator and of the assistant. The aerosol was found to remain in the air up to 30 min after scaling. Conclusions: The occupational health hazards of dental aerosols can be minimized by following simple, inexpensive precautions. Keywords: Aerosol, Splatter, Infection control, Aerosol contamination in dentistry, Dental unit water lines, Ultrasonic scaling

Investigation of different types of filters for atmospheric trace elements analysis by three analytical techniques

International Nuclear Information System (INIS)

Ali, A.E.; Bacso, J.

1996-01-01

Different atmospheric aerosol samples were collected on three types of filters. Disks of both loaded and clean areas of each kind of filter were investigated by XRF, PIXE and Scanning Electron Microscope (SEM) methods. The blank concentration values of the elements Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br and Pb in the three types of filters are discussed. It is found that for trace elemental analysis, the Nuclepore membrane filters are the most suitable for sampling. These have much lower blank element concentration values than the glass fibres and ash free filters. It was found also that the PIXE method is a more reliable analytical technique for atmospheric aerosol particles than the other methods. (author). 20 refs., 3 figs., 3 tabs

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

Science.gov (United States)

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

2007-12-01

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

Measuring aerosols generated inside armoured vehicles perforated by depleted uranium ammunition

International Nuclear Information System (INIS)

Parkhurst, M.A.

2003-01-01

In response to questions raised after the Gulf War about the health significance of exposure to depleted uranium (DU), the US Department of Defense initiated a study designed to provide an improved scientific basis for assessment of possible health effects on soldiers in vehicles struck by these munitions. As part of this study, a series of DU penetrators were fired at an Abrams tank and a Bradley fighting vehicle, and the aerosols generated by vehicle perforation were collected and characterised. A robust sampling system was designed to collect aerosols in this difficult environment and monitor continuously the sampler flow rates. The aerosol samplers selected for these tests included filter cassettes, cascade impactors, a five-stage cyclone and a moving filter. Sampler redundancy was an integral part of the sampling system to offset losses from fragment damage. Wipe surveys and deposition trays collected removable deposited particulate matter. Interior aerosols were analysed for uranium concentration and particle size distribution as a function of time. They were also analysed for uranium oxide phases, particle morphology and dissolution in vitro. These data, currently under independent peer review, will provide input for future prospective and retrospective dose and health risk assessments of inhaled or ingested DU aerosols. This paper briefly discusses the target vehicles, firing trajectories, aerosol samplers and instrumentation control systems, and the types of analyses conducted on the samples. (author)

Nuclear analytical techniques applied to characterization of atmospheric aerosols in Amazon Region

International Nuclear Information System (INIS)

Gerab, Fabio; Artaxo, Paulo

1996-01-01

This work presents the atmospheric aerosols characterization that exist in different regions of Amazon basin. The biogenic aerosol emission by forest, as well as the atmospheric emissions of particulate materials due to biomass burning, were analyzed. Samples of aerosol particles were collected during three years in two different locations of Amazon region using Stacked Unit Filters. In order to study these samples some analytical nuclear techniques were used. The high concentrations of aerosols as a result of biomass burning process were observed in the period of june-september

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

aerosol decay masses between the developed fission product module and MELCOR code. These discrepancies come from model differences of the aerosol sedimentation and steam condensation. The fission product module will be updated on the species release from the gap between the fuel and cladding, decay heat evaluation, aerosol size tracking, etc.

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

aerosol decay masses between the developed fission product module and MELCOR code. These discrepancies come from model differences of the aerosol sedimentation and steam condensation. The fission product module will be updated on the species release from the gap between the fuel and cladding, decay heat evaluation, aerosol size tracking, etc.

Predicting mass loading as a function of pressure difference across prefilter/HEPA filter systems

International Nuclear Information System (INIS)

Novick, V.J.; Klassen, J.F.; Monson, P.R.

1992-01-01

The purpose of this work is to develop a methodology for predicting the mass loading and pressure drop effects on a prefilter/ HEPA filter system. The methodology relies on the use of empirical equations for the specific resistance of the aerosol loaded filter as a function of the particle diameter. These correlations relate the pressure difference across a filter to the mass loading on the filter and accounts for aerosol particle density effects. These predictions are necessary for the efficient design of new filtration systems and for risk assessment studies of existing filter systems. This work specifically addresses the prefilter/HEPA filter Airborne Activity Confinement Systems (AACS) at the Savannah River Plant. In order to determine the mass loading on the system, it is necessary to establish the efficiency characteristics for the prefilter, the mass loading characteristics of the prefilter measured as a function of pressure difference across the prefilter, and the mass loading characteristics of the HEPA filter as a function of pressure difference across the filter. Furthermore, the efficiency and mass loading characteristics need to be determined as a function of the aerosol particle diameter. A review of the literature revealed that no previous work had been performed to characterize the prefilter material of interest. In order to complete the foundation of information necessary to predict total mass loadings on prefilter/HEPA filter systems, it was necessary to determine the prefilter efficiency and mass loading characteristics. The measured prefilter characteristics combined with the previously determined HEPA filter characteristics allowed the resulting pressure difference across both filters to be predicted as a function of total particle mass for a given particle distribution. These predictions compare favorably to experimental measurements (±25%)

Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Dubey, Manvendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aiken, Allison [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, Larry K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Andrew [Aerodyne Research, Inc., Billerica, MA (United States); Gorkowski, Kyle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-01

We deployed Aerodyne Research Inc.’s first Cavity Attenuated Phase Shift extinction (CAPS PMex) monitor (built by Aerodyne) that measures light extinction by using a visible-light-emitting diode (LED) as a light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector in Cape Cod in 2012/13 for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Two-Column Aerosol Project (TCAP). The efficacy of this instrument is based on the fact that aerosols are broadband scatterers and absorbers of light. The input LED is square-wave modulated and passed through the sample cell that distorts it due to exponential decay by aerosol light absorption and scattering; this is measured at the detector. The amount of phase shift of the light at the detector is used to determine the light extinction. This extinction measurement provides an absolute value, requiring no calibration. The goal was to compare the CAPS performance with direct measurements of absorption with ARM’s baseline photoacoustic soot spectrometer (PASS-3) and nephelometer instruments to evaluate its performance.

Nanoparticle filtration performance of NIOSH-certified particulate air-purifying filtering facepiece respirators: evaluation by light scattering photometric and particle number-based test methods.

Science.gov (United States)

Rengasamy, Samy; Eimer, Benjamin C

2012-01-01

National Institute for Occupational Safety and Health (NIOSH) certification test methods employ charge neutralized NaCl or dioctyl phthalate (DOP) aerosols to measure filter penetration levels of air-purifying particulate respirators photometrically using a TSI 8130 automated filter tester at 85 L/min. A previous study in our laboratory found that widely different filter penetration levels were measured for nanoparticles depending on whether a particle number (count)-based detector or a photometric detector was used. The purpose of this study was to better understand the influence of key test parameters, including filter media type, challenge aerosol size range, and detector system. Initial penetration levels for 17 models of NIOSH-approved N-, R-, and P-series filtering facepiece respirators were measured using the TSI 8130 photometric method and compared with the particle number-based penetration (obtained using two ultrafine condensation particle counters) for the same challenge aerosols generated by the TSI 8130. In general, the penetration obtained by the photometric method was less than the penetration obtained with the number-based method. Filter penetration was also measured for ambient room aerosols. Penetration measured by the TSI 8130 photometric method was lower than the number-based ambient aerosol penetration values. Number-based monodisperse NaCl aerosol penetration measurements showed that the most penetrating particle size was in the 50 nm range for all respirator models tested, with the exception of one model at ~200 nm size. Respirator models containing electrostatic filter media also showed lower penetration values with the TSI 8130 photometric method than the number-based penetration obtained for the most penetrating monodisperse particles. Results suggest that to provide a more challenging respirator filter test method than what is currently used for respirators containing electrostatic media, the test method should utilize a sufficient number

Removal of nitrogen oxides, 106RuO4 vapors and radioactive aerosols from the gas originating in radioactive wastes solidification

International Nuclear Information System (INIS)

Kepak, F.; Pecak, V.; Uher, E.; Kanka, J.; Koutova, S.; Matous, V.

1985-01-01

Procedures and equipment for the disposal of nitrogen oxides, RuO 4 vapors and radioactive aerosols of 90 Sr, 137 Cs, 60 Co and 125 Sb contained in the gas generated in the solidification of high- and intermediate-level radioactive wastes were tested on models. Nitrogen oxides were disposed of by absorption and chemical decomposition in various solutions of which the best results gave solutions of ammonium salts. Absorption in solutions, physical and chemical sorption on inorganic sorbents were tested for the disposal of RuO 4 . Aerosols were disposed of by absorption in absorption media with subsequent filtration. Of fibrous filter materials, Czechoslovak AEROS-2 and RA-2 filter papers were proven in the tests. Attention was also devoted to granular filter materials of which silica gel was chosen. On the basis of laboratory tests a multi-step treatment system was designed which consists of a condenser, a nitrogen oxide absorber, a liquid aerosol separator, absorption columns and aerosol filters. The whole system has been manufactured on pilot plant scale and the different parts are being produced. (Z.M.)

The continuous field measurements of soluble aerosol compositions at the Taipei Aerosol Supersite, Taiwan

Science.gov (United States)

Chang, Shih-Yu; Lee, Chung-Te; Chou, Charles C.-K.; Liu, Shaw-Chen; Wen, Tian-Xue

The characteristics of ambient aerosols, affected by solar radiation, relative humidity, wind speed, wind direction, and gas-aerosol interaction, changed rapidly at different spatial and temporal scales. In Taipei Basin, dense traffic emissions and sufficient solar radiation for typical summer days favored the formation of secondary aerosols. In winter, the air quality in Taipei Basin was usually affected by the Asian continental outflows due to the long-range transport of pollutants carried by the winter monsoon. The conventional filter-based method needs a long time for collecting aerosols and analyzing compositions, which cannot provide high time-resolution data to investigate aerosol sources, atmospheric transformation processes, and health effects. In this work, the in situ ion chromatograph (IC) system was developed to provide 15-min time-resolution data of nine soluble inorganic species (Cl -, NO 2-, NO 3-, SO 42-, Na +, NH 4+, K +, Mg 2+ and Ca 2+). Over 89% of all particles larger than approximately 0.056 μm were collected by the in situ IC system. The in situ IC system is estimated to have a limit of detection lower than 0.3 μg m -3 for the various ambient ionic components. Depending on the hourly measurements, the pollutant events with high aerosol concentrations in Taipei Basin were associated with the local traffic emission in rush hour, the accumulation of pollutants in the stagnant atmosphere, the emission of industrial pollutants from the nearby factories, the photochemical secondary aerosol formation, and the long-range transport of pollutants from Asian outflows.

The background aerosol in the lower stratosphere and the tropospheric aerosol in the Alps. Final report; Das Hintergrundaerosol der unteren Stratosphaere und das troposphaerische Aerosol der Alpen. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Jaeger, H.; Trickl, T.

2001-06-04

As a contribution to the German Aerosol-Lidar Network lidar backscatter measurements have been carried out at Garmisch-Partenkirchen in a wide range of the atmosphere from next to the ground to altitudes beyond 30 km. The investigations, on one hand, were devoted to establishing a climatology of the aerosol extinction coefficient for the northern Alps and to prolonging the long-term measurement series of the stratospheric aerosol. On the other hand, aerosol was used as a tracer of polluted air masses in atmospheric transport studies (orographically induced vertical transport, advection of Saharan dust, as well as aerosol advection from the North american boundary layer and from large-scale wild fire in the United States and Canada). These transport processes given the seasonal cycle of the aerosol throughout the troposphere. In the free troposphere a pronounced spring-time aerosol maximum was found. The stratospheric aerosol concentration had decayed to a background-type level during the reporting period. As a consequence, the influence of smaller aerosol contributions could be distinguished such as the eruption of the volcano Shishaldin (Alaska) and aircraft emissions. (orig.) [German] Im Rahmen des deutschen Aerosollidarnetzes wurden in Garmisch-Partenkirchen Lidar-Rueckstreumessungen in einem weiten Bereich der Atmosphaere von Bodennaehe bis in ueber 30 km Hoehe durchgefuehrt. Die Arbeiten dienten zum einen der Erstellung einer Klimatologie des Aerosol-Extinktionskoeffizienten fuer die Nordalpen sowie der Verlaengerung der seit 1976 erstellten Langzeitmessreihe des stratosphaerischen Aerosols. Zum anderen fanden atmosphaerische Transportstudien statt, bei denen das Aerosol als 'Tracer' fuer Luftverschmutzung verwendet wurde (orographisch induzierter Vertikaltransport, Advektion von Saharastaub und Aerosoladvektion aus der nordamerikanischen Genzschicht und von grossflaechigen Waldbraenden in den U.S.A. und Kanada). Diese Transportprozesse bestimmen den

Contribution to the study of water-soluble ions in aerosols of the city of Antananarivo

International Nuclear Information System (INIS)

NASSUR, R.

2007-01-01

The urban environment characterized by concentration accumulated activities (industries-heating-transports) polluted emission (chimney, silencer...) concentration in atmosphere and especially people exposed in effects. All this elements make that the urban people are confronted in increasing sanitary risk, especially for the most susceptible subject. Three places in Antananarivo are chosen to value ions soluble in water, in aerosols of the town by human activities especially in road transport. Samples analysis are presented like collected aerosols in filters. In order to value these pollutions, we used ''dichotomous'' samples to collect the particles and analysis method by ionic chromatography to analysis ions. With sampling system, it is possible to carry out collect to be allowed the separation of breathed and inhaled particles in two filters of different diameter. The aerosol are to be deduct in advance to 1,40m of ground. The filters impregnated into water without ions are waged during 30 minutes, to obtain samples representative after filtration. Some ions NH4 + , Na + , Br - are lower in our detection limits. These are Ca 2+ and S0 4 2- that the majority is collected from Antananarivo aerosols. [fr

HEPA filter concerns - an overview

Energy Technology Data Exchange (ETDEWEB)

Leonard, J.F. [Department of Energy, Washington, DC (United States)

1995-02-01

The U.S. Department of Energy (DOE) recently initiated a complete review of the DOE High Efficiency Particulate Air (HEPA) Filter Program to identify areas for improvement. Although this process is currently ongoing, various issues and problems have already been identified for action that not only impacts the DOE HEPA filter program, but potentially the national and international air cleaning community as well. This paper briefly reviews a few of those concerns that may be of interest, and discusses actions initiated by the DOE to address the associated issues and problems. Issues discussed include: guidance standards, in-place testing, specifications, Test Facilities, portable units, vacuum cleaners, substitute aerosols, filter efficiencies, aging/shelf life/service life, fire suppression, handbook, Quality Products List (QPL), QA testing, and evaluations.

Experience with Aerosol Generation During Rotary Mode Core Sampling in the Hanford Single Shell Waste Tanks

International Nuclear Information System (INIS)

SCHOFIELD, J.S.

2000-01-01

This document provides data on aerosol concentrations in tank head spaces, total mass of aerosols in the tank head space and mass of aerosols sent to the exhauster during Rotary Mode Core Sampling from November 1994 through June 1999. A decontamination factor for the RMCS exhauster filter housing is calculated based on operation data

High-efficiency particulate air filter test activities at the Department of Energy

International Nuclear Information System (INIS)

Bresson, J.F.

1987-01-01

For the past 2 years, test activities at the three Department of Energy HEPA Filter Test Facilities (FTFs) have been conducted under a unified set of operating standards intended to help achieve consistency in test methods and test results. Reviews of test operations are conducted at each FTF annually, and technical support and guidance are provided on request. Round Robin tests are conducted twice a year to compare penetration and resistance test results among the three FTFs. The FTFs prepare summary test data twice a year, and the data is analyzed for trends with respect to ongoing quality of HEPA filters in nuclear facilities. Data and conclusions from both the Round Robin tests and semiannual reports are discussed, the latter without reference to specific manufacturers. The new DOE standards include provisions for consideration and approval of new test aerosols or test methods, under closely controlled change procedures. Progress in obtaining DOE approval for DOS as a new aerosol, and for the Alternative Test System (ATS) developed by, and reported on by the LANL, as an approved new test method are discussed, as are 2 significant changes in standard NE-F-3-43, related to (a) toxicology test alternatives, and (b) the test aerosol definition. Finally, the emergence of new, higher flow rated HEPA filters and Ultra Low Particulate Air (ULPA) filters will impact DOE's design, procurement, testing and use of HEPA filters in the near future

An Improved Cambridge Filter Pad Extraction Methodology to Obtain More Accurate Water and “Tar” Values: In Situ Cambridge Filter Pad Extraction Methodology

Directory of Open Access Journals (Sweden)

Ghosh David

2014-07-01

Full Text Available Previous investigations by others and internal investigations at Philip Morris International (PMI have shown that the standard trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387 (Cigarettes -- Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine, is not suitable for high-water content aerosols. Errors occur because of water losses during the opening of the Cambridge filter pad holder to remove the filter pad as well as during the manual handling of the filter pad, and because the commercially available filter pad holder, which is constructed out of plastic, may adsorb water. This results in inaccurate values for the water content, and erroneous and overestimated values for Nicotine Free Dry Particulate Matter (NFDPM. A modified 44 mm Cambridge filter pad holder and extraction equipment which supports in situ extraction methodology has been developed and tested. The principle of the in situ extraction methodology is to avoid any of the above mentioned water losses by extracting the loaded filter pad while kept in the Cambridge filter pad holder which is hermetically sealed by two caps. This is achieved by flushing the extraction solvent numerous times through the hermetically sealed Cambridge filter pad holder by means of an in situ extractor. The in situ methodology showed a significantly more complete water recovery, resulting in more accurate NFDPM values for high-water content aerosols compared to the standard ISO methodology. The work presented in this publication demonstrates that the in situ extraction methodology applies to a wider range of smoking products and smoking regimens, whereas the standard ISO methodology only applies to a limited range of smoking products and smoking regimens, e.g., conventional cigarettes smoked under ISO smoking regimen. In cases where a comparison of yields between the PMI HTP and

ITER vent filter conceptual study. Final report ITER Task S71 TD 70 (NID-9e) EU Task SEA 3-4

Energy Technology Data Exchange (ETDEWEB)

Blomquist, R; Johansson, Kjell; Natalizio, A; Nilsson, Lars; Shen, K; Sjoeberg, A

1995-02-01

The aim of this study is to investigate vent filter technologies that could be applied to ITER in accidental situations and to discuss how effective they could be in reducing accidental releases of gases, vapors and aerosols to the atmosphere. The study`s main contents are: A description of vent filter technologies as they are used for fission reactors; A review of appropriate tritium removal technologies. The vent filter part deals mainly with aerosol removal. The tritium part includes removal of both elemental and oxidized tritium from the vent flow. An important conclusion is that current fission reactor vent filter systems do not remove elemental tritium from the vent stream. A third part of the study is scoping thermal-hydraulic and aerosol transport analyses in order to find realistic vent flow rates and aerosol transport characteristics. Theses analyses, which are based on ITER design data assumed at the time of analysis, have been performed by means of the codes RELAP5 and CONTAIN. Release estimates are also included. Suggestions and recommendations are given regarding how to design a reliable vent filter system. Suggested vent systems include: Vent ducts from vacuum vessel and heat exchanger departments, a water pool for condensation of steam, and equipment for removal of aerosols, elemental tritium and oxidized tritium. 42 refs, 6 tabs, 34 figs.

ITER vent filter conceptual study. Final report ITER Task S71 TD 70 (NID-9e) EU Task SEA 3-4

International Nuclear Information System (INIS)

Blomquist, R.; Johansson, Kjell; Natalizio, A.; Nilsson, Lars; Shen, K.; Sjoeberg, A.

1995-02-01

The aim of this study is to investigate vent filter technologies that could be applied to ITER in accidental situations and to discuss how effective they could be in reducing accidental releases of gases, vapors and aerosols to the atmosphere. The study's main contents are: A description of vent filter technologies as they are used for fission reactors; A review of appropriate tritium removal technologies. The vent filter part deals mainly with aerosol removal. The tritium part includes removal of both elemental and oxidized tritium from the vent flow. An important conclusion is that current fission reactor vent filter systems do not remove elemental tritium from the vent stream. A third part of the study is scoping thermal-hydraulic and aerosol transport analyses in order to find realistic vent flow rates and aerosol transport characteristics. Theses analyses, which are based on ITER design data assumed at the time of analysis, have been performed by means of the codes RELAP5 and CONTAIN. Release estimates are also included. Suggestions and recommendations are given regarding how to design a reliable vent filter system. Suggested vent systems include: Vent ducts from vacuum vessel and heat exchanger departments, a water pool for condensation of steam, and equipment for removal of aerosols, elemental tritium and oxidized tritium. 42 refs, 6 tabs, 34 figs

Efficiency and mass loading characteristics of a typical HEPA filter media material

International Nuclear Information System (INIS)

Novick, V.J.; Higgins, P.J.; Dierkschiede, B.; Abrahamson, C.; Richardson, W.B.; Monson, P.R.; Ellison, P.G.

1991-01-01

The particle removal efficiency of the high-efficiency particulate air (HEPA) filter material used at the Savannah River Site was measured as a function of monodisperse particle diameter and two gas filtration velocities. the results indicate that the material meets or exceeds the minimum specified efficiency of 99.97% for all particle diameters at both normal and minimum operating flow conditions encountered at the Savannah River site. The pressure drop across the HEPA filter material used at the Savannah River site was measured as a function of particle mass loading for various aerosol size distributions. The pressure drop was found to increase linearly with the particle mass loaded onto the filters, as long as the particles were completely dry. The slope of the curve was found to be dependent on the particle diameter and velocity of the aerosol. The linear behavior between the initial pressure drop (clean filter) and the final pressure drop (loaded filter) implies that the filtration mechanism is dominated by the particle cake that rapidly forms on the front surface of the HEPA filter. This behavior is consistent with the high filtration efficiency of the material

Aerosol entrainment from a sparged non-Newtonian slurry

International Nuclear Information System (INIS)

Fritz, Brad G.

2006-01-01

Aerosol measurements were conducted above a half-scale air sparged mixing tank filled with simulated waste slurry. Three aerosol size fractions were measured at three sampling heights at three different sparging rates using a filter based ambient air sampling technique. Aerosol concentrations in the head space above the closed tank demonstrated a wide range, varying between 97 ?g m-3 for PM2.5 and 5650 ?g m-3 for TSP. The variation in concentrations was a function of sampling heights, size fraction and sparging rate. Measured aerosol entrainment coefficients showed good agreement with existing entrainment models. The models evaluated generally over predicted the entrainment, but were within a factor of two of the measured entrainment. This indicates that the range of applicability of the models may be extendable to include sparged slurries with Bingham plastic rheological properties

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

During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

Realization of radioactive equilibrium in the KRISS radon chamber

International Nuclear Information System (INIS)

Lee, Mo Sung; Park, Tae Soon; Lee, Jong Man

2013-01-01

The maintenance of radioactive equilibrium between radon and its decay products in a radon chamber is necessary to calibrate radon decay product monitors. In this study, the activity concentrations of radon decay products have been measured, and mosquito-repellent incense has been used to produce aerosol particles in the chamber. Filter papers with 8 μm pore size were used to collect aerosol in the chamber. The activity concentrations of radon decay products have been evaluated by the Modified Tsivoglou Method. The correction factors due to the differences in counting time requirements of the Modified Tsivoglou Method and the time delay between consecutive measurements have been determined. Finally, the radioactive equilibrium has been confirmed by applying the Bateman equation. - Highlights: • The activity concentrations of radon decay products are evaluated by the Modified Tsivoglou Method. • Mosquito-repellent incense is used to produce aerosol particles in the radon chamber. • The radioactive equilibrium in the chamber was achieved within 2 days and confirmed by the Bateman equation

Attachment of radon progeny to cigarette-smoke aerosols

International Nuclear Information System (INIS)

Biermann, A.H.; Sawyer, S.R.

1995-05-01

The daughter products of radon gas are now recognized as a significant contributor to radiation exposure to the general public. It is also suspected that a synergistic effect exists with the combination cigarette smoking and radon exposure. We have conducted an experimental investigation to determine the physical nature of radon progeny interactions with cigarette smoke aerosols. The size distributions of the aerosols are characterized and attachment rates of radon progeny to cigarette-smoke aerosols are determined. Both the mainstream and sidestream portions of the smoke aerosol are investigated. Unattached radon progeny are very mobile and, in the presence of aerosols, readily attach to the particle surfaces. In this study, an aerosol chamber is used to contain the radon gas, progeny and aerosol mixture while allowing the attachment process to occur. The rate of attachment is dependent on the size distribution, or diffusion coefficient, of the radon progeny as well as the aerosol size distribution. The size distribution of the radon daughter products is monitored using a graded-screen diffusion battery. The diffusion battery also enables separation of the unattached radon progeny from those attached to the aerosol particles. Analysis of the radon decay products is accomplished using alpha spectrometry. The aerosols of interest are size fractionated with the aid of a differential mobility analyzer and cascade impactor. The measured attachment rates of progeny to the cigarette smoke are compared to those found in similar experiments using an ambient aerosol. The lowest attachment coefficients observed, ∼10 -6 cm 3 /s, occurred for the ambient aerosol. The sidestream and mainstream smoke aerosols exhibited higher attachment rates in that order. The results compared favorably with theories describing the coagulation process of aerosols

Selection of filter media in alpha air monitors for emergency environmental monitoring

International Nuclear Information System (INIS)

Kinouchi, N.; Oishi, T.; Noguchi, H.; Kato, S.

2000-01-01

We have developed an alpha air monitor which is possible to measure rapidly and sensitively the concentrations of airborne alpha-emitting particles, such as plutonium, for the environmental monitoring at an accident of nuclear reprocessing plant. The monitor is designed to collect airborne alpha-emitting particles by drawing the ambient air through a filter and to detect the activity by alpha spectroscopy. In order to achieve high-sensitive measurements, selection of a suitable filter used in the monitor is considerably important. The most important requirement for the filter is that it has a high surface collection efficiency to obtain the sharpness of the alpha energy spectrum. This makes it easy to distinguish the alpha-ray peak of plutonium from the alpha spectrum of naturally occurring radon decay products in the environment. And the filter is also desired to have low resistance of the air flow so that particles can be collected at a high flowrate. We have made a comparison of the surface collection efficiency and pressure drop for the various filters. Types of the test filters, most of which are commercially available in Japan, were glass fiber, cellulose-glass fiber, membrane and so on. The surface collection efficiency has been evaluated by the following two indices. One was the sharpness of alpha-ray energy peaks of thoron decay products generated in a laboratory and collected in the fibers. The other was the background counts of radon decay products in a plutonium region by measuring alpha-ray energy spectrum of radon decay products collected in the filters by sampling of dust in the atmosphere. It was found that the PTFE (polytetrafluoroethylene) membrane filter with backing had a high surface collection efficiency and low pressure drop. The results of the test are described in detail in this paper. (author)

Mexico City aerosol study

International Nuclear Information System (INIS)

Falcon, Y.I.; Ramirez, C.R.

1987-01-01

A major task in the field of air pollution monitoring is the development of devices for determining the mass and composition of airborne particulate matter as a function of size - and time. The sample collection device must be designed giving consideration to the nature of the aerosol and to the effects of the aerosol on human health. It has been established that particles smaller than 3.5 μm in diameter can penetrate deeply into the human respiratory system, and that larger particles are trapped in the upper respiratory passages. For these reasons, it is desirable to use a dichotomous sampler to collect particles in two size ranges, rather than to collect total particulates on a single filter. The authors discuss a study in Mexico City using a dichotomous sampler

The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

International Nuclear Information System (INIS)

Bartlett, W.T.; Walker, B.A.

1996-01-01

Alpha continuous air monitors (CAMs) will be used at the Waste Isolation Pilot Plant (WIPP) to measure airborne transuranic radioactivity that might be present in air exhaust or in work-place areas. WIPP CAMs are important to health and safety because they are used to alert workers to airborne radioactivity, to actuate air-effluent filtration systems, and to detect airborne radioactivity so that the radioactivity can be confined in a limited area. In 1993, the Environmental Evaluation Group (EEG) reported that CAM operational performance was affected by salt aerosol, and subsequently, the WIPP CAM design and usage were modified. In this report, operational data and current theories on aerosol collection were reviewed to determine CAM quantitative performance limitations. Since 1993, the overall CAM performance appears to have improved, but anomalous alpha spectra are present when sampling-filter salt deposits are at normal to high levels. This report shows that sampling-filter salt deposits directly affect radon-thoron daughter alpha spectra and overall monitor efficiency. Previously it was assumed that aerosol was mechanically collected on the surface of CAM sampling filters, but this review suggests that electrostatic and other particle collection mechanisms are more important than previously thought. The mechanism of sampling-filter particle collection is critical to measurement of acute releases of radioactivity. 41 refs

Comparison of Emery 3004 and 3006 characteristics with DOP for possible use in HEPA filter leak tests

Energy Technology Data Exchange (ETDEWEB)

Kovach, B.J.; Banks, E.M.; Kovacs, G. [Nuclear Consulting Services, Inc., Columbus, OH (United States)

1995-02-01

The particle size distribution, concentration, liquid to aerosol conversion rate and ignition properties of DOP, Emery 3004 and Emery 3006 aerosols generated by the NUCON Aerosol Generators Models SN-10 and DG-F were obtained. Results demonstrate the Emery products are acceptable replacements for DOP in performing leak testing of HEPA filters.

Aerosol single-scattering albedo and asymmetry parameter from MFRSR observations during the ARM Aerosol IOP 2003

Directory of Open Access Journals (Sweden)

E. I. Kassianov

2007-06-01

Full Text Available Multi-filter Rotating Shadowband Radiometers (MFRSRs provide routine measurements of the aerosol optical depth (τ at six wavelengths (0.415, 0.5, 0.615, 0.673, 0.870 and 0.94 μm. The single-scattering albedo (π₀ is typically estimated from the MFRSR measurements by assuming the asymmetry parameter (g. In most instances, however, it is not easy to set an appropriate value of g due to its strong temporal and spatial variability. Here, we introduce and validate an updated version of our retrieval technique that allows one to estimate simultaneously π₀ and g for different types of aerosol. We use the aerosol and radiative properties obtained during the Atmospheric Radiation Measurement (ARM Program's Aerosol Intensive Operational Period (IOP to validate our retrieval in two ways. First, the MFRSR-retrieved optical properties are compared with those obtained from independent surface, Aerosol Robotic Network (AERONET, and aircraft measurements. The MFRSR-retrieved optical properties are in reasonable agreement with these independent measurements. Second, we perform radiative closure experiments using the MFRSR-retrieved optical properties. The calculated broadband values of the direct and diffuse fluxes are comparable (~5 W/m² to those obtained from measurements.

A study of regional-scale aerosol assimilation using a Stretch-NICAM

Science.gov (United States)

Misawa, S.; Dai, T.; Schutgens, N.; Nakajima, T.

2013-12-01

Although aerosol is considered to be harmful to human health and it became a social issue, aerosol models and emission inventories include large uncertainties. In recent studies, data assimilation is applied to aerosol simulation to get more accurate aerosol field and emission inventory. Most of these studies, however, are carried out only on global scale, and there are only a few researches about regional scale aerosol assimilation. In this study, we have created and verified an aerosol assimilation system on regional scale, in hopes to reduce an error associated with the aerosol emission inventory. Our aerosol assimilation system has been developed using an atmospheric climate model, NICAM (Non-hydrostaric ICosahedral Atmospheric Model; Satoh et al., 2008) with a stretch grid system and coupled with an aerosol transport model, SPRINTARS (Takemura et al., 2000). Also, this assimilation system is based on local ensemble transform Kalman filter (LETKF). To validate this system, we used a simulated observational data by adding some artificial errors to the surface aerosol fields constructed by Stretch-NICAM-SPRINTARS. We also included a small perturbation in original emission inventory. This assimilation with modified observational data and emission inventory was performed in Kanto-plane region around Tokyo, Japan, and the result indicates the system reducing a relative error of aerosol concentration by 20%. Furthermore, we examined a sensitivity of the aerosol assimilation system by varying the number of total ensemble (5, 10 and 15 ensembles) and local patch (domain) size (radius of 50km, 100km and 200km), both of which are the tuning parameters in LETKF. The result of the assimilation with different ensemble number 5, 10 and 15 shows that the larger the number of ensemble is, the smaller the relative error become. This is consistent with ensemble Kalman filter theory and imply that this assimilation system works properly. Also we found that assimilation system

Sources and atmospheric processing of organic aerosol in the Mediterranean: insights from aerosol mass spectrometer factor analysis

Directory of Open Access Journals (Sweden)

L. Hildebrandt

2011-12-01

Full Text Available Atmospheric particles were measured in the late winter (25 February–26 March 2009 at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2009. A quadrupole aerosol mass spectrometer (Q-AMS was employed to quantify the size-resolved chemical composition of non-refractory submicron aerosol, and a thermodenuder was used to analyze the organic aerosol (OA volatility. Complementary measurements included particle size distributions from a scanning mobility particle sizer, inorganic and organic particle composition from filter analysis, air ion concentrations, O₃, NO_x and NO_y concentrations, and meteorological measurements. Factor analysis was performed on the OA mass spectra, and the variability in OA composition could best be explained with three OA components. The oxygenated organic aerosol (OOA was similar in composition and volatility to the summertime OA previously measured at this site and may represent an effective endpoint in particle-phase oxidation of organics. The two other OA components, one associated with amines (Amine-OA and the other probably associated with the burning of olive branches (OB-OA, had very low volatility but were less oxygenated. Hydrocarbon-like organic aerosol (HOA was not detected. The absence of OB-OA and Amine-OA in the summer data may be due to lower emissions and/or photochemical conversion of these components to OOA.

Nuclear track radiography of 'hot' aerosol particles

Energy Technology Data Exchange (ETDEWEB)

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

1999-06-01

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

In-place HEPA filter penetration test

International Nuclear Information System (INIS)

Bergman, W.; Wilson, K.; Elliott, J.; Bettencourt, B.; Slawski, J.W.

1997-01-01

We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in- place penetration test is practical

Evaluation of the effect of media velocity on filter efficiency and most penetrating particle size of nuclear grade high-efficiency particulate air filters.

Science.gov (United States)

Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A

2008-11-01

High-efficiency particulate air (HEPA) filters are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine particles; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine particles. In this study, the performance of nuclear grade HEPA filters, with respect to filter efficiency and most penetrating particle size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA filters (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a particle size distribution centered near the HEPA filter most penetrating particle size. Filters were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. Filter efficiency and most penetrating particle size measurements were made throughout the duration of filter testing. Filter efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The filter most penetrating particle size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that filters operating at media velocities up to 4.5 cm/sec will meet or exceed current filter efficiency requirements. Additionally

Two-Column Aerosol Project (TCAP): Ground-Based Radiation and Aerosol Validation Using the NOAA Mobile SURFRAD Station Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Michalsky, Joseph [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States); Lantz, Kathy [Univ. of Colorado, Boulder, CO (United States)

2016-05-01

The National Oceanic and Atmospheric Administration (NOAA) is preparing for the launch of the Geostationary Operational Environmental Satellite R-Series (GOES-R) satellite in 2015. This satellite will feature higher time (5-minute versus 30-minute sampling) and spatial resolution (0.5 km vs 1 km in the visible channel) than current GOES instruments provide. NOAA’s National Environmental Satellite Data and Information Service has funded the Global Monitoring Division at the Earth System Research Laboratory to provide ground-based validation data for many of the new and old products the new GOES instruments will retrieve specifically related to radiation at the surface and aerosol and its extensive and intensive properties in the column. The Two-Column Aerosol Project (TCAP) had an emphasis on aerosol; therefore, we asked to be involved in this campaign to de-bug our new instrumentation and to provide a new capability that the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Mobile Facilities (AMF) did not possess, namely surface albedo measurement out to 1625 nm. This gave us a chance to test remote operation of our new multi-filter rotating shadowband radiometer/multi-filter radiometer (MFRSR/MFR) combination. We did not deploy standard broadband shortwave and longwave radiation instrumentation because ARM does this as part of every AMF deployment. As it turned out, the ARM standard MFRSR had issues, and we were able to provide the aerosol column data for the first 2 months of the campaign covering the summer flight phase of the deployment. Using these data, we were able to work with personnel at Pacific Northwest National Laboratory (PNNL) to retrieve not only aerosol optical depth (AOD), but single scattering albedo and asymmetry parameter, as well.

Daily and seasonal variation of aerosol concentration in the atmosphere near the surface in continental climate of Siberia

Energy Technology Data Exchange (ETDEWEB)

Koutsenogii, P [Inst. of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

1996-12-31

Novosibirsk region is the area in southern part of West-Siberian lowland, covering about 200,000 km{sup 2}. The properties of atmospheric aerosol in Novosibirsk region were studied during few campaigns in the years 1992 and 1993, one complex expedition in Summer of 1994 and durable observations in Akademgorodok in the years 1993, 1994. Akademgorodok is situated 25 km S from the city Novosibirsk, has population of about 100,000 and no industry. Three different locations in remote areas of Novosibirsk region were used for the measurements. The first was situated 12 km E from Akademgorodok, and 30 km from Novosibirsk near the village Kljutchi. The second location was situated close to Lake Tchany in western part of Novosibirsk region. The third location was situated in south-western part of Novosibirsk region, 12 km from the town Karasuk. The total aerosol light scattering by aerosol particles was measured by commercially available nephelometer FAN-A in terms of units, related to the molecular scattering of clean air, measured by the same nephelometer. Aerosol samples in which the content of sulfate-, nitrate-, and cloride-anions was determined, using ion liquid chromatography, were collected with Whatman 41 or AFA-HA filters. Aerosol mass concentration was measured by weighting of AFA-HA filters. Aerosol particles were sampled on the filters with the volume velocity of about 500 l/min for Whatman 41 and 120 l/min for AFA-HA and mean sampling duration of 24 hours. The total aerosol number concentration was measured with a condensation nuclei counter TSI 3020

Daily and seasonal variation of aerosol concentration in the atmosphere near the surface in continental climate of Siberia

Energy Technology Data Exchange (ETDEWEB)

Koutsenogii, P. [Inst. of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

1995-12-31

Novosibirsk region is the area in southern part of West-Siberian lowland, covering about 200,000 km{sup 2}. The properties of atmospheric aerosol in Novosibirsk region were studied during few campaigns in the years 1992 and 1993, one complex expedition in Summer of 1994 and durable observations in Akademgorodok in the years 1993, 1994. Akademgorodok is situated 25 km S from the city Novosibirsk, has population of about 100,000 and no industry. Three different locations in remote areas of Novosibirsk region were used for the measurements. The first was situated 12 km E from Akademgorodok, and 30 km from Novosibirsk near the village Kljutchi. The second location was situated close to Lake Tchany in western part of Novosibirsk region. The third location was situated in south-western part of Novosibirsk region, 12 km from the town Karasuk. The total aerosol light scattering by aerosol particles was measured by commercially available nephelometer FAN-A in terms of units, related to the molecular scattering of clean air, measured by the same nephelometer. Aerosol samples in which the content of sulfate-, nitrate-, and cloride-anions was determined, using ion liquid chromatography, were collected with Whatman 41 or AFA-HA filters. Aerosol mass concentration was measured by weighting of AFA-HA filters. Aerosol particles were sampled on the filters with the volume velocity of about 500 l/min for Whatman 41 and 120 l/min for AFA-HA and mean sampling duration of 24 hours. The total aerosol number concentration was measured with a condensation nuclei counter TSI 3020

Some considerations about the natural atmospheric radioactive aerosol

International Nuclear Information System (INIS)

Renoux, A.; Madelaine, G.

1985-01-01

From experiments made in Brest by the use of a semi-automatic device for direct measurements of atmospheric radon (the double filter method), we obtained daily average values of Radon 222 concentration, and establish that the values obtained are completely different according to the wind direction. We establish that radioactive balance is never realized in the air between radon and its daughters RaA(Po218), RaB(Pb214) and RaC(Bi214); the state of radioactive balance strongly depends on wind direction. We also study the ionic state of the radioactive aerosol accruing from Radon 222. Using an experimental system consisting of absolute filters, diffusion batteries, cascade impactors and ions tubes, we establish the size distribution of natural radioactive aerosol. We thus show 40% of the natural atmospheric radioactivity is located on particles whose radii are inferior to 2 . 10-2 mm. A good agreement is provided between the theory and our experimental points

Metrological certification of aerosol and iodine channels in instrumentation for radiation monitoring at nuclear power plants

International Nuclear Information System (INIS)

Belkina, S.K.; Zalmanzon, Yu.E.; Ivanova, A.P.

1988-01-01

The method for converting the value of a volume activity unit of radioactive aerosols using the state special standard for operating measurement devices by means of aerosol sources is suggested. The sources are aerosol samples selected for a filter by means of the proper type of a detection unit or a radiometer and, thus, providing full coincidence of measurement geometry of aerosol sample activity during radiation monitoring. Application of aerosol samples permits to solve the problem of metrological certification and verification of aerosol and iodine channels of radiation safety monitoring systems under operating conditions without their dismantling and to establish the unity and correctness in the field of measurement of volume activity of 131 I aerosols at NPP

A Monte-Carlo investigation of the uncertainty of acoustic decay measurements

DEFF Research Database (Denmark)

Cabo, David Pérez; Seoane, Manuel A. Sobreira; Jacobsen, Finn

2012-01-01

Measurement of acoustic decays can be problematic at low frequencies: short decays cannot be evaluated accurately. Several effects influencing the evaluation will be reviewed in this paper. As new contribution, the measurement uncertainty due to one-third octave band pass filters will be analysed...

A constant flow filter air sampler for workplace environments

International Nuclear Information System (INIS)

Parulian, A.; Rodgers, J.C.; McFarland, A.R.

1996-01-01

A filter air sampler has been developed for sampling radionuclide aerosol particles form the workplace environment. It provides easy filter changing, constant flow sampling, and a visual display to indicate proper operation. An experimental study was conducted to characterize the collection efficiency of the sampler as affected by variations in room air velocity, particle size, sampling flow rate, inlet geometry, and inlet orientation to the free stream. Tests were carried out in a wing tunnel at velocities between 0.3 m s -1 and 2.0 m s -1 , which is a range that covers anticipated velocities in the typical highly ventilated workplace environment of a nuclear facility. Nearly monodisperse aerosols with sizes between 5 and 20 μm aerodynamic diameter were sampled at flow rates between 28.3 and 84.9 L min -1 . Inlet orientations of 0 degree, 90 degree, and 180 degree from the horizontal were selected for evaluation. When the sampler was oriented at 0 degree over various ranges of free stream velocities, sampling flow rates and particle sizes, the transmission efficiency of aerosol was typically greater than 95%. The transmission efficiencies varied form 80% to 106% for 10-μm aerodynamic diameter particles over the previously noted range of free stream velocities and inlet orientations. Uniformity of deposits of 10 μm aerodynamic diameter particles on collection filters was examined for a sampling rate of 57 L min -1 , a sampler orientation of 90 degree into the wind and wind speeds of 0.3-2 m s -1 . The coefficients of variation for the areal density of the deposits ranged from 6.1% to 37.2%. A miniature critical flow venturi with a constant sampling flow rate of 57 L min -1 was developed for application to the new filter air sampler. It was demonstrated that the performance of the new filter air sampler is quite acceptable over a wide range of conditions. 31 refs., 8 figs., 1 tab

Multiple HEPA filter test methods. Progress report, January--December 1977

International Nuclear Information System (INIS)

Schuster, B.; Kyle, T.; Osetek, D.

1978-09-01

Tandem high-efficiency particulate air (HEPA) filter efficiency measurements have been successfully performed on a large number of 20,000 CFM installations. The testing procedure relies on the use of a laser intracavity particle spectrometer and a very high-volume thermal dioctyl phthalate aerosol generator designed and constructed specifically for this purpose. For systems that cannot be tested in this fashion, work has been initiated on the generation and detection of a fluorescent self-identifying aerosol to eliminate the background problem. General candidate aerosols and methods to disperse them have been uncovered. Two distinct detection concepts have evolved for the measurement of size and concentration of these particles

The Fate of Mengovirus on Fiberglass Filter of Air Handling Units.

Science.gov (United States)

Bandaly, Victor; Joubert, Aurélie; Le Cann, Pierre; Andres, Yves

2017-12-01

One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation, and air-conditioning systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, and fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces, or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber filter F7 used in AHU. In this study, a set-up close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the electrical low pressure impact and the scanner mobility particle size and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the filter and in the biosampler showed that mengovirus can pass through the filter and remain infectious upstream and downstream the system. Regarding the virus infectivity on the filter under a constant air flow, mengovirus was remained infectious during 10 h after aerosolization.

HEPA Filter Performance under Adverse Conditions

International Nuclear Information System (INIS)

Parsons, Michael; Hogancamp, Kristina; Alderman, Steven; Waggoner, Charles

2007-01-01

This study involved challenging nuclear grade high-efficiency particulate air (HEPA) filters under a variety of conditions that can arise in Department of Energy (DOE) applications such as: low or high RH, controlled and uncontrolled challenge, and filters with physically damaged media or seals (i.e., leaks). Reported findings correlate filter function as measured by traditional differential pressure techniques in comparison with simultaneous instrumental determination of up and down stream PM concentrations. Additionally, emission rates and failure signatures will be discussed for filters that have either failed or exceeded their usable lifetime. Significant findings from this effort include the use of thermocouples up and down stream of the filter housing to detect the presence of moisture. Also demonstrated in the moisture challenge series of tests is the effect of repeated wetting of the filter. This produces a phenomenon referred to as transient failure before the tensile strength of the media weakens to the point of physical failure. An evaluation of the effect of particle size distribution of the challenge aerosol on loading capacity of filters is also included. Results for soot and two size distributions of KCl are reported. Loading capacities for filters ranged from approximately 70 g of soot to nearly 900 g for the larger particle size distribution of KCl. (authors)

Study on generation and granulometry of a standard aerosol of CINa for use in determinations of filtration efficiency of absolute filters; Estudio sobre la generacion y granulometria de un aerosol patron de CINa para la determinacion de eficacias filtrantes de filtros absolutos

Energy Technology Data Exchange (ETDEWEB)

Milla, E

1978-07-01

This work has as objective the study of the conditions of generation and granulometry of an aerosol generated by atomizing with compressed a i r a solution of CINa in water in order to obtain particles, CINa cubes. The droplets of the spray formed are dried in a stream of air, acting as a carrier, inside the pipe of a bank of test filters. The granulometric analysis has been carried out by sampling in the gaseous phase. A dispersion photometer was used that yields the size spectrum of particles. The variables concerned in generation, whose influence on aerosol granulometry were analyzed are: characteristic diameter of atomizer unit, pressure of compressed air of generation, concentration of saline solution, temperature of air carrier, length of bank pipe, sampling position across a section, length of sampling duct and ratio between speeds in pipe and duct. (Author) 50 refs.

Receptor models for source apportionment of remote aerosols in Brazil

International Nuclear Information System (INIS)

Artaxo Netto, P.E.

1985-11-01

The PIXE (particle induced X-ray emission), and PESA (proton elastic scattering analysis) method were used in conjunction with receptor models for source apportionment of remote aerosols in Brazil. The PIXE used in the determination of concentration for elements with Z >- 11, has a detection limit of about 1 ng/m 3 . The concentrations of carbon, nitrogen and oxygen in the fine fraction of Amazon Basin aerosols was measured by PESA. We sampled in Jureia (SP), Fernando de Noronha, Arembepe (BA), Firminopolis (GO), Itaberai (GO) and Amazon Basin. For collecting the airbone particles we used cascade impactors, stacked filter units, and streaker samplers. Three receptor models were used: chemical mass balance, stepwise multiple regression analysis and principal factor analysis. The elemental and gravimetric concentrations were explained by the models within the experimental errors. Three sources of aerosol were quantitatively distinguished: marine aerosol, soil dust and aerosols related to forests. The emission of aerosols by vegetation is very clear for all the sampling sites. In Amazon Basin and Jureia it is the major source, responsible for 60 to 80% of airborne concentrations. (Author) [pt

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

A study on characteristics and sources of winter time atmospheric aerosols in Kyoto and Seoul using PIXE and supplementary analysis

International Nuclear Information System (INIS)

Ma, C.-J.; Kasahara, M.; Tohno, S.; Yeo, H.-G.

1999-01-01

Atmospheric aerosols were collected using a two stages filter sampler to classify into the fine and coarse fraction in Kyoto and Seoul in winter season. Elemental concentrations of aerosols were analyzed by PIXE and EAS as well as ion concentrations by IC. Analyzed data were used to source of aerosol particles. (author)

Process for retention of iodine and aerosols during containment venting

International Nuclear Information System (INIS)

Eckardt, B.; Betz, R.; Greger, G.U.; Werner, K.D.

1990-05-01

A process for retention of the majority of aerosols and iodine during containment venting was optimized. For this purpose, sections of a two-stage process comprising a venturi scrubber and a metal-fiber filter demister were tested under containment venting conditions assumed to prevail during a hypothetical core - melt accident and optimized with a view to achieving high decontamination factors and loading capacity while minimizing the size of the process. The loading and retention tests performed in a scrubber operating pressure range between 1 and 10 bar, at temperatures from 50 to 200degC (also boiling pools) and in air and steam atmospheres. Under these unfavorable conditions for aerosol retention, the retention efficiencies were determined at various flow rates with soluble and non-soluble aerosols as well as gaseous iodine. The retention efficiencies for BaSO 4 , uranine and SnO 2 aerosols were determined to be 99.95% to 99.99% for venturi scrubbers with metal-fiber filter demister. The retention efficiency for elemental iodine was determined to be ≥99% including revolatization effects over a 24-hour operating period. The high loading capacity of the venturi scrubber unit was verified after process modifications with various aerosols. The use of full-scale process section together with the best possible simulation of containment venting conditions by the test parameters ensured that the results can be transferred to real venting equipment. The aim of ensuring the retention of the majority of the aerosol-borne activity and of elemental iodine activity and minimizing the process size was clearly achieved and verified by means of this optimized venting equipment under an extremely wide range of hypothetical core-melt accident conditions. (orig.) With 17 refs., 3 tabs., 35 annexes [de

Automated methods for thorium determination in liquids, solids and aerosols

International Nuclear Information System (INIS)

Robertson, R.; Stuart, J.E.

1984-01-01

Methodology for determining trace thorium levels in a variety of sample types for compliance purposes was developed. Thorium in filtered water samples is concentrated by ferric hydroxide co-precipitation. Aerosols on glass-fibre, cellulose ester or teflon filters are acid digested and thorium is concentrated by lanthanum fluoride co-precipitation. Chemical separation and measurement are then done on a Technicon AAII-C auto-analyzer via TTA-solvent extraction and colorimetry using the thorium-arsenazo III colour complex. Solid samples are acid digested and thorium is concentrated and separated using lanthanum fluoride co-precipitation followed by anion-exchange chromatography. Measurement is then carried out on the autoanalyzer by direct development of the thorium-arsenazo III colour complex. Chemical yields are determined through the addition of thorium-234 tracer with assay by gamma-ray spectrometry. The sensitivities of the methods for liquids, aerosols and solids are approximately 1μg/L,0.5μg and 0.5 μg/g respectively. At thorium levels about ten times the detection limits, accuracy and reproducibility are typically +-10 percent for liquids and aerosols and +- 15 percent for solid samples

Detection of 210Po on filter papers 16 years after use for the collection of short-lived radon progeny in a room

International Nuclear Information System (INIS)

Abu-Jarad, F.; Fazal-ur-Rehman

2003-01-01

Radon gas was allowed to accumulate in its radium source and then injected into a 36 m 3 test room, resulting in an initial radon concentration of 15 kBq m -3 . Filter papers were used to collect the short-lived radon progeny and thus to measure the Potential Alpha Energy Concentration (PAEC) in-situ in the year 1984 at different times and conditions according to the experimental design. The radon progeny collected on the filter papers were studied as a function of aerosol particle concentration ranging from 10 2 -10 5 particles cm -3 in three different experiments. The highest aerosol particle concentration was generated by indoor cigarette smoking. Those filters were stored after the experiment, and were used after 16 years to study the activity of the radon long-lived alpha emitter progeny, 210 Po (T 1/2 =138 days). This isotope is separated from the short-lived progeny by 210 Pb beta emitter with 22.3 years half-life. After 16 years' storage of these filters, each filter paper was sandwiched and wrapped between two CR-39 nuclear track detectors, to put the detectors in contact with the surfaces of different filters, for 337 days. Correlation between the PAEC measured using filter papers in the year 1984 and the activity of long-lived alpha emitter 210 Po on the same filter papers measured in the year 2000 were studied. The results of the 210 Po activity showed a very good correlation of 0.92 with the PAEC 16 years ago. The results also depict that the PAEC and 210 Po activity in indoor air increased with the increase of aerosol particle concentration, which shows the attachment of short-lived radon progeny with the aerosol particles. The experiment proves that indoor cigarette smoking is a major source of aerosol particles carrying radon progeny and, thus, indoor cigarette smoking is an additional source of internal radiation hazard to the occupants whether smoker or non-smoker

ISS Ambient Air Quality: Updated Inventory of Known Aerosol Sources

Science.gov (United States)

Meyer, Marit

2014-01-01

Spacecraft cabin air quality is of fundamental importance to crew health, with concerns encompassing both gaseous contaminants and particulate matter. Little opportunity exists for direct measurement of aerosol concentrations on the International Space Station (ISS), however, an aerosol source model was developed for the purpose of filtration and ventilation systems design. This model has successfully been applied, however, since the initial effort, an increase in the number of crewmembers from 3 to 6 and new processes on board the ISS necessitate an updated aerosol inventory to accurately reflect the current ambient aerosol conditions. Results from recent analyses of dust samples from ISS, combined with a literature review provide new predicted aerosol emission rates in terms of size-segregated mass and number concentration. Some new aerosol sources have been considered and added to the existing array of materials. The goal of this work is to provide updated filtration model inputs which can verify that the current ISS filtration system is adequate and filter lifetime targets are met. This inventory of aerosol sources is applicable to other spacecraft, and becomes more important as NASA considers future long term exploration missions, which will preclude the opportunity for resupply of filtration products.

40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

Science.gov (United States)

2010-07-01

... through which sample air is flowing during performance of this test. (3) A no-flow filter is a sample filter through which no sample air is intended to flow during performance of this test. (4) A channel is... a device or means to allow or cause the aerosol to be routed to one of several channels. (c...

Filter media properties of mineral fibres produced by plasma spray.

Science.gov (United States)

Prasauskas, Tadas; Matulevicius, Jonas; Kliucininkas, Linas; Krugly, Edvinas; Valincius, Vitas; Martuzevicius, Dainius

2016-01-01

The purpose of this study was to determine the properties of fibrous gas filtration media produced from mineral zeolite. Fibres were generated by direct current plasma spray. The paper characterizes morphology, chemical composition, geometrical structure of elementary fibres, and thermal resistance, as well as the filtration properties of fibre media. The diameter of the produced elementary fibres ranged from 0.17 to 0.90 μm and the length ranged from 0.025 to 5.1 mm. The release of fibres from the media in the air stream was noticed, but it was minimized by hot-pressing the formed fibre mats. The fibres kept their properties up to the temperature of 956°C, while further increase in temperature resulted in the filter media becoming shrunk and brittle. The filtration efficiency of the prepared filter mats ranged from 95.34% to 99.99% for aerosol particles ranging in a size between 0.03 and 10.0 μm. Unprocessed fibre media showed the highest filtration efficiency when filtering aerosol particles smaller than 0.1 µm. Hot-pressed filters were characterized by the highest quality factor values, ranging from 0.021 to 0.064 Pa(-1) (average value 0.034 Pa(-1)).

Passive self-cleaning aerosol scrubber

International Nuclear Information System (INIS)

Postma, A.K.

1981-01-01

A hybrid gas scrubbing system is described, which includes features of both a pool type scrubber and a sand or ground filter, for use on nuclear reactor containment buildings to limit release of aerosol particles and absorbable gases, including radio-active materials, during postulated major accidents. The system requires no energy while in the passive state and no active energy other than pressurization of the stream of gas being scrubbed. (U.K.)

A sensitivity analysis of volcanic aerosol dispersion in the stratosphere. [Mt. Fuego, Guatemala eruptions

Science.gov (United States)

Butler, C. F.

1979-01-01

A computer sensitivity analysis was performed to determine the uncertainties involved in the calculation of volcanic aerosol dispersion in the stratosphere using a 2 dimensional model. The Fuego volcanic event of 1974 was used. Aerosol dispersion processes that were included are: transport, sedimentation, gas phase sulfur chemistry, and aerosol growth. Calculated uncertainties are established from variations in the stratospheric aerosol layer decay times at 37 latitude for each dispersion process. Model profiles are also compared with lidar measurements. Results of the computer study are quite sensitive (factor of 2) to the assumed volcanic aerosol source function and the large variations in the parameterized transport between 15 and 20 km at subtropical latitudes. Sedimentation effects are uncertain by up to a factor of 1.5 because of the lack of aerosol size distribution data. The aerosol chemistry and growth, assuming that the stated mechanisms are correct, are essentially complete in several months after the eruption and cannot explain the differences between measured and modeled results.

Controlling exposure to DPM : diesel particulate filters vs. biodiesel

International Nuclear Information System (INIS)

Bugarski, A.D.; Shi, X.C.

2009-01-01

In order to comply with Mine Safety and Health Administration regulations, mining companies are required to reduce miners exposures to diesel particulate matter (DPM) to 160 μg/m 3 of total carbon. Diesel particulate filter (DPF) systems, disposable filter elements (DFEs), and diesel oxidation catalysts (DOCs) are among the most effective strategies and technologies for curtailing DPM at its source. Substituting diesel fuel with biodiesel blends is also considered to be a plausible solution by many underground mine operators. Studies were conducted at the National Institute for Occupational Safety and Health Diesel Laboratory at Lake Lynn Experimental Mine to evaluate various control technologies and strategies available to the underground mining industry to reduce exposure to DPM. The physical, chemical and toxicological properties of diesel aerosols (DPM) emitted by engines in an underground mine were also evaluated. The DPF and DFE systems were found to be highly effective in reducing total particulate and elemental carbon mass concentrations, total aerosol surface concentrations and, in most cases, concentrations of diesel aerosols in occupational settings such as underground mines. Soy methyl ester (SME) biodiesel fuels had the potential to reduce the mine air concentrations of total DPM, although the rate of reduction varied depending on engine operating conditions. The disadvantage of using biodiesel fuels was an increase in the fraction of particle-bound volatile organics and concentration of aerosols for light-load engine operating conditions.

In-place HEPA filter penetration test

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Wilson, K.; Elliott, J. [Lawrence Livermore National Lab., CA (United States)] [and others

1997-08-01

We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in-place penetration test is practical. 14 refs., 14 figs., 3 tabs.

Methods for in-place testing of HEPA and iodine filters used in nuclear power plants

International Nuclear Information System (INIS)

Holmberg, R.; Laine, J.

1978-04-01

The purpose of this work was a general investigation of existing in-place test methods and to build an equipment for in-place testing of HEPA and iodine sorption filters. In this work the discussion is limited to methods used in in-place testing of HEPA and iodine sorption filters used in light-water-cooled reactor plants. Dealy systems, built for the separation of noble gases, and testing of them is not discussed in the work. Contaminants present in the air of a reactor containment can roughly be diveded into three groups: aerosols, reactive gases, and noble gases. The aerosols are filtered with HEPA (High Efficiency Particulate Air) filters. The most important reactive gases are molecular iodine and its two compounds: hydrogen iodide and methyl iodide. Of gases to be removed by the filters methyl iodide is the gas most difficult to remove especially at high relative humidities. Impregnated activated charcoal is generally used as sorption material in the iodine filters. Experience gained from the use of nuclear power plants proves that the function of high efficiency air filter systems can not be considered safe until this is proved by in-place tests. In-place tests in use are basically equal. A known test agent is injected upstream of the filter to be tested. The efficiency is calculated from air samples taken from both sides of the filter. (author)

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.

Description of test facilities bound to the research on sodium aerosols - some significant results

Energy Technology Data Exchange (ETDEWEB)

Dolias, M; Lafon, A; Vidard, M; Schaller, K H [DRNR/STRS - Centre de Cadarache, Saint-Paul-lez-Durance (France)

1977-01-01

This communication is dedicated to the description of the CEA (French Atomic Energy Authority) testing located at CADARACHE and which are utilized for the study of sodium aerosols behavior. These testing loops are necessary for studying the operating of equipment such as filters, sodium vapour traps, condensers and separators. It is also possible to study the effect of characteristics parameters on formation, coagulation and carrying away of sodium aerosols in the cover gas. Sodium aerosols deposits in a vertical annular space configuration with a cold area in its upper part are also studied. Some significant results emphasize the importance of operating conditions on the formation of aerosols. (author)

Applications of particle induced X-ray emission analysis to ambient aerosol studies

International Nuclear Information System (INIS)

Lannefors, H.

1982-01-01

The characteristics of Particle Induced X-ray Emission (PIXE) analysis in conjunction with different ambient aerosol samplers have been studied. Correction factors have been calculated for homogeneous and inhomogeneous rural and urban aerosol samples. The Nuclepore two stage filter sampler provided the most useful combination of the resolution and particle size fractionation in urban, rural and remote environments. The PIXE-analysis technique in combination with different samplers was employed in aerosol composition studies in rural and remote environments. Particular emphasis was laid on studies of aerosol long range transport. Based on air mass trajectory analysis and aerosol composition measurements the foreign contribution in southern Sweden was estimated to be 70 - 80% for S and Pb but only 30 - 50% for V and Ni. The spatial and temporal extension of a long range transport episode was studied using high time resolution continuous filter samplers in a network in southern Sweden. The variation in the concentration levels of sulphur agreed well with changes in the air mass history. Arctic summer elemental concentration levels as measured during the Swedish YMER-80 icebreaker expedition were typically one order of magnitude lower than Arctic winter levels. The combination of chemical information, optical properties and size distribution data supports the hypothesis of long range transport of air pollution into the Arctic especially during the winter. This takes place during the winter season because the Polar front is further south making conditions for long range transport up to the Arctic more favourable. (Auth.)

Development of the Ensemble Navy Aerosol Analysis Prediction System (ENAAPS and its application of the Data Assimilation Research Testbed (DART in support of aerosol forecasting

Directory of Open Access Journals (Sweden)

J. I. Rubin

2016-03-01

Full Text Available An ensemble-based forecast and data assimilation system has been developed for use in Navy aerosol forecasting. The system makes use of an ensemble of the Navy Aerosol Analysis Prediction System (ENAAPS at 1 × 1°, combined with an ensemble adjustment Kalman filter from NCAR's Data Assimilation Research Testbed (DART. The base ENAAPS-DART system discussed in this work utilizes the Navy Operational Global Analysis Prediction System (NOGAPS meteorological ensemble to drive offline NAAPS simulations coupled with the DART ensemble Kalman filter architecture to assimilate bias-corrected MODIS aerosol optical thickness (AOT retrievals. This work outlines the optimization of the 20-member ensemble system, including consideration of meteorology and source-perturbed ensemble members as well as covariance inflation. Additional tests with 80 meteorological and source members were also performed. An important finding of this work is that an adaptive covariance inflation method, which has not been previously tested for aerosol applications, was found to perform better than a temporally and spatially constant covariance inflation. Problems were identified with the constant inflation in regions with limited observational coverage. The second major finding of this work is that combined meteorology and aerosol source ensembles are superior to either in isolation and that both are necessary to produce a robust system with sufficient spread in the ensemble members as well as realistic correlation fields for spreading observational information. The inclusion of aerosol source ensembles improves correlation fields for large aerosol source regions, such as smoke and dust in Africa, by statistically separating freshly emitted from transported aerosol species. However, the source ensembles have limited efficacy during long-range transport. Conversely, the meteorological ensemble generates sufficient spread at the synoptic scale to enable observational impact

Detection of {sup 210}Po on filter papers 16 years after use for the collection of short-lived radon progeny in a room

Energy Technology Data Exchange (ETDEWEB)

Abu-Jarad, F. E-mail: falah.abujarad@aramco.com; Fazal-ur-Rehman

2003-07-01

Radon gas was allowed to accumulate in its radium source and then injected into a 36 m{sup 3} test room, resulting in an initial radon concentration of 15 kBq m{sup -3}. Filter papers were used to collect the short-lived radon progeny and thus to measure the Potential Alpha Energy Concentration (PAEC) in-situ in the year 1984 at different times and conditions according to the experimental design. The radon progeny collected on the filter papers were studied as a function of aerosol particle concentration ranging from 10{sup 2}-10{sup 5} particles cm{sup -3} in three different experiments. The highest aerosol particle concentration was generated by indoor cigarette smoking. Those filters were stored after the experiment, and were used after 16 years to study the activity of the radon long-lived alpha emitter progeny, {sup 210}Po (T{sub 1/2}=138 days). This isotope is separated from the short-lived progeny by {sup 210}Pb beta emitter with 22.3 years half-life. After 16 years' storage of these filters, each filter paper was sandwiched and wrapped between two CR-39 nuclear track detectors, to put the detectors in contact with the surfaces of different filters, for 337 days. Correlation between the PAEC measured using filter papers in the year 1984 and the activity of long-lived alpha emitter {sup 210}Po on the same filter papers measured in the year 2000 were studied. The results of the {sup 210}Po activity showed a very good correlation of 0.92 with the PAEC 16 years ago. The results also depict that the PAEC and {sup 210}Po activity in indoor air increased with the increase of aerosol particle concentration, which shows the attachment of short-lived radon progeny with the aerosol particles. The experiment proves that indoor cigarette smoking is a major source of aerosol particles carrying radon progeny and, thus, indoor cigarette smoking is an additional source of internal radiation hazard to the occupants whether smoker or non-smoker.

Data Filtering and Assimilation of Satellite Derived Aerosol Optical Depth, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Satellite observations of the Earth often contain excessive noise and extensive data voids. Aerosol measurements, for instance, are obscured and contaminated by...

Characterization and cytotoxic assessment of ballistic aerosol particulates for tungsten alloy penetrators into steel target plates.

Science.gov (United States)

Machado, Brenda I; Murr, Lawrence E; Suro, Raquel M; Gaytan, Sara M; Ramirez, Diana A; Garza, Kristine M; Schuster, Brian E

2010-09-01

The nature and constituents of ballistic aerosol created by kinetic energy penetrator rods of tungsten heavy alloys (W-Fe-Ni and W-Fe-Co) perforating steel target plates was characterized by scanning and transmission electron microscopy. These aerosol regimes, which can occur in closed, armored military vehicle penetration, are of concern for potential health effects, especially as a consequence of being inhaled. In a controlled volume containing 10 equispaced steel target plates, particulates were systematically collected onto special filters. Filter collections were examined by scanning and transmission electron microscopy (SEM and TEM) which included energy-dispersive (X-ray) spectrometry (EDS). Dark-field TEM identified a significant nanoparticle concentration while EDS in the SEM identified the propensity of mass fraction particulates to consist of Fe and FeO, representing target erosion and formation of an accumulating debris field. Direct exposure of human epithelial cells (A549), a model for lung tissue, to particulates (especially nanoparticulates) collected on individual filters demonstrated induction of rapid and global cell death to the extent that production of inflammatory cytokines was entirely inhibited. These observations along with comparisons of a wide range of other nanoparticulate species exhibiting cell death in A549 culture may suggest severe human toxicity potential for inhaled ballistic aerosol, but the complexity of the aerosol (particulate) mix has not yet allowed any particular chemical composition to be identified.

Characterization and Cytotoxic Assessment of Ballistic Aerosol Particulates for Tungsten Alloy Penetrators into Steel Target Plates

Directory of Open Access Journals (Sweden)

Brian E. Schuster

2010-08-01

Full Text Available The nature and constituents of ballistic aerosol created by kinetic energy penetrator rods of tungsten heavy alloys (W-Fe-Ni and W-Fe-Co perforating steel target plates was characterized by scanning and transmission electron microscopy. These aerosol regimes, which can occur in closed, armored military vehicle penetration, are of concern for potential health effects, especially as a consequence of being inhaled. In a controlled volume containing 10 equispaced steel target plates, particulates were systematically collected onto special filters. Filter collections were examined by scanning and transmission electron microscopy (SEM and TEM which included energy-dispersive (X-ray spectrometry (EDS. Dark-field TEM identified a significant nanoparticle concentration while EDS in the SEM identified the propensity of mass fraction particulates to consist of Fe and FeO, representing target erosion and formation of an accumulating debris field. Direct exposure of human epithelial cells (A549, a model for lung tissue, to particulates (especially nanoparticulates collected on individual filters demonstrated induction of rapid and global cell death to the extent that production of inflammatory cytokines was entirely inhibited. These observations along with comparisons of a wide range of other nanoparticulate species exhibiting cell death in A549 culture may suggest severe human toxicity potential for inhaled ballistic aerosol, but the complexity of the aerosol (particulate mix has not yet allowed any particular chemical composition to be identified.

Evaluating MODIS Collection 6 Dark Target Over Water Aerosol Products for Multi-sensor Data Fusion

Science.gov (United States)

Shi, Y.; Zhang, J.; Reid, J. S.; Hyer, E. J.; McHardy, T. M.; Lee, L.

2014-12-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol products have been widely used in aerosol related climate, visibility, and air quality studies for more than a decade. Recently, the MODIS collection 6 (c6) aerosol products from MODIS-Aqua have been released. The reported changes between Collection 5 and Collection 6 include updates in the retrieving algorithms and a new cloud filtering process for the over-ocean products. Thus it is necessary to fully evaluate the collection 6 products for applications that require high quality MODIS aerosol optical depth data, such as operational aerosol data assimilation. The uncertainties in the MODIS c6 DT over ocean products are studied through both inter-comparing with the Multi-angle Imaging Spectroradiometer (MISR) aerosol products and by evaluation against ground truth. Special attention is given to the low bias in MODIS DT products due to the misclassifications of heavy aerosol plumes as clouds. Finally, a quality assured data assimilation grade aerosol optical product is constructed for aerosol data assimilation related applications.

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

Science.gov (United States)

Rutter, Andrew P; Schauer, James J

2007-06-01

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

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.

Airborne Atmospheric Aerosol Measurement System

Science.gov (United States)

Ahn, K.; Park, Y.; Eun, H.; Lee, H.

2015-12-01

It is important to understand the atmospheric aerosols compositions and size distributions since they greatly affect the environment and human health. Particles in the convection layer have been a great concern in global climate changes. To understand these characteristics satellite, aircraft, and radio sonde measurement methods have usually been used. An aircraft aerosol sampling using a filter and/or impactor was the method commonly used (Jay, 2003). However, the flight speed particle sampling had some technical limitations (Hermann, 2001). Moreover, the flight legal limit, altitude, prohibited airspace, flight time, and cost was another demerit. To overcome some of these restrictions, Tethered Balloon Package System (T.B.P.S.) and Recoverable Sonde System(R.S.S.) were developed with a very light optical particle counter (OPC), impactor, and condensation particle counter (CPC). Not only does it collect and measure atmospheric aerosols depending on altitudes, but it also monitors the atmospheric conditions, temperature, humidity, wind velocity, pressure, GPS data, during the measurement (Eun, 2013). In this research, atmospheric aerosol measurement using T.B.P.S. in Ansan area is performed and the measurement results will be presented. The system can also be mounted to an unmanned aerial vehicle (UAV) and create an aerial particle concentration map. Finally, we will present measurement data using Tethered Balloon Package System (T.B.P.S.) and R.S.S (Recoverable Sonde System).

Aerosol challenges to air cleaning systems during severe accidents in nuclear plants

International Nuclear Information System (INIS)

Gieseke, J.A.

1985-01-01

A variety of air cleaning systems may be operating in nuclear power plants and under severe accident conditions, these systems may be treating airborne concentrations of aerosols which are very high. Predictions of airborne aerosol concentrations in nuclear power plant containments under severe accident conditions are reviewed to provide a basis for evaluating the potential effects on the air cleaning systems. The air cleaning systems include filters, absorber beds, sprays, water pools, ice beds, and condensers. Not all of these were intended to operate as air cleaners but will in fact be good aerosol collectors. Knowledge of expected airborne concentrations will allow better evaluation of system performances

Aerosol characterizaton in El Paso-Juarez airshed using optical methods

Science.gov (United States)

Esparza, Angel Eduardo

2011-12-01

retrieve the size distribution of them. This method permits the assessment of aerosols in the ambient in-situ, without physically extracting them from their current state, as the filter technique does. The second objective was an analysis and comparison of the aerosol optical thickness (AOT) data between ground-based instruments and satellite data. In this project, the groundbased instruments are the Multi Filter Rotating Shadowband Radiometers (MFRSR) installed at UTEP and the nearest sun photometer facility, a NASA's Aerosol Robotic Network (AERONET), located at White Sands, New Mexico. The satellite data is provided by the NASA's Multi-angle Imaging Spectro-radiometer (MISR) instrument located in the Terra satellite. Finally, the third objective was to estimate ground particulate matter concentration of particles no greater than 2.5 mum in diameter (PM2.5) by using the MISR's satellite data. This objective was achieved by implementing an empirical mathematical model that includes measured data. In addition, this model addressed the geographic characteristics of the region as well as several factors such as season, relative humidity (RH) and the height of the planetary boundary layer (PBL).

Time resolved aerosol monitoring in the urban centre of Soweto

Science.gov (United States)

Formenti, P.; Annegarn, H. J.; Piketh, S. J.

1998-03-01

A programme of aerosol sampling was conducted from 1982 to 1984 in the urban area of Soweto, Johannesburg, South Africa. The particulate matter (aerodynamic diameter source apportionment of crustal elements between coal smoke and traffic induced road dust, based on chemical elemental measurements. A novel technique is demonstrated for processing PIXE-derived time sequence elemental concentration vectors. Slowly varying background components have been extracted from sulphur and crustal aerosol components, using alternatively two digital filters: a moving minimum, and a moving average. The residuals of the crustal elements, assigned to locally generated aerosol components, were modelled using surrogate tracers: sulphur as a surrogate for coal smoke; and Pb as a surrogate for traffic activity. Results from this source apportionment revealed coal emissions contributed between 40% and 50% of the aerosol mineral matter, while 18-22% originated from road dust. Background aerosol, characteristic of the regional winter aerosol burden over the South African Highveld, was between 12% and 21%. Minor contributors identified included a manganese smelter, located 30 km from the sampling site, and informal trash burning, as the source of intermittent heavy metals (Cu, Zn). Elemental source profiles derived for these various sources are presented.

α-spectrometric device equipped with semi-conductors for direct measurement of transuranium elements on large area filters

International Nuclear Information System (INIS)

Fessler, H.; Pawelzik, J.

1984-10-01

A device was developed with an array of 8 silicon surface barrier detectors inside a vacuum chamber containing a rotating sample holder for large areas (200 mm diameter) aerosol filters. It serves for quick identification of α-emitters on these aerosol filters, and allows to measure the α-particles with a relatively constant efficiency along a filter diameter. Thus, the radiochemical treatment of single filters can be avoided. Troubles appeared in the course of development of defective semiconductors and their temperature dependence. To suppress the influence of temperature a cooling device was built. During practical testing a cross-efficiency of 13.6% was measured. It is possible to identify α-emitting nuclides with an activity of 10 -1 Bq per sample during about 2 hours of measuring time. Appropriate methodes of calculation are indicated. The data output of the device is suited for transfer to a computer. (orig./HP) [de

Dual aerosol detector based on forward light scattering with a single laser beam

International Nuclear Information System (INIS)

Kovach, B.J.; Custer, R.A.; Powers, F.L.; Kovach, A.

1985-01-01

The in-place leak testing of HEPA filter banks using a single detector can lead to some error in the measurement due to the fluctuation of the aerosol concentration while the single detector is being switched from the upstream to downstream sampling. The time duration of the test also can cause unnecessarily high DOP loading of the HEPA filters and in some cases higher radiation exposure to the testing personnel. The new forward light scattering detector uses one 632.8 nm laser beam for aerosol detection in a dual chamber sampling and detecting aerosol concentration simultaneously both upstream and downstream. This manner of operation eliminates the errors caused by concentration variations between upstream and downstream sample points while the switching takes place. The new detector uses large area silicone photodiodes with a hole in the center, to permit uninterrupted passage of the laser beam through the downstream sample chamber. The nonlinearity due to the aerosol over population of the laser beam volume is calculated to be less than 1% using a Poisson distribution method to determine the average distance of the particles. A simple pneumatic system prevents mixing of the upstream and downstream samples even in wide pressure variations of the duct system

Aerosol composition and source apportionment in Santiago de Chile

Science.gov (United States)

Artaxo, Paulo; Oyola, Pedro; Martinez, Roberto

1999-04-01

Santiago de Chile, São Paulo and Mexico City are Latin American urban areas that suffer from heavy air pollution. In order to study air pollution in Santiago area, an aerosol source apportionment study was designed to measure ambient aerosol composition and size distribution for two downtown sampling sites in Santiago. The aerosol monitoring stations were operated in Gotuzo and Las Condes during July and August 1996. The study employed stacked filter units (SFU) for aerosol sampling, collecting fine mode aerosol (dpsource apportionment was performed using Absolute Principal Factor Analysis (APFA). Very high aerosol concentrations were observed (up to 400 μg/m 3 PM 10). The main aerosol particle sources in Santiago are resuspended soil dust and traffic emissions. Coarse particles account for 63% of PM 10 aerosol in Gotuzo and 53% in Las Condes. A major part of this component is resuspended soil dust. In the fine fraction, resuspended soil dust accounts for 15% of fine mass, and the aerosols associated with transportation activities account for a high 64% of the fine particle mass. Sulfate particle is an important component of the aerosol in Santiago, mainly originating from gas-to-particle conversion from SO 2. In the Gotuzo site, sulfates are the highest aerosol component, accounting for 64.5% of fine mass. Direct traffic emissions are generally mixed with resuspended soil dust. It is difficult to separate the two components, because the soil dust in downtown Santiago is contaminated with Pb, Br, Cl, and other heavy metals that are also tracers for traffic emissions. Residual oil combustion is observed, with the presence of V, S and Ni. An aerosol components from industrial emissions is also present, with the presence of several heavy metals such as Zn, Cu and others. A factor with molybdenum, arsenic, copper and sulfur was observed frequently, and it results from emissions of copper smelters.

Performance of HEPA filters under severe conditions, 3

International Nuclear Information System (INIS)

Osaki, Makoto; Zanma, Tokugo; Kanagawa, Akira.

1986-01-01

Performance of high efficiency particulate air (HEPA) filters at temperatures from ambient to 240 deg C was measured to prove that HEPA filters kept up their regulated decontamination factor (DF) at elevated temperatures. The DF for NaCl aerosol was measured by using a laser particle spectrometer. Pressure drop of HEPA filters at elevated temperatures was also measured. The DF increased at elevated temperatures. The DF at 200 deg C was an order of magnitude higher than that at ambient. The change of DF at elevated temperatures of various HEPA filters was effectively evaluated by using the ratio of single fiber collection efficiencies at ambient to those at elevated temperatures. Pressure drop of HEPA filters also increased at elevated temperatures. The pressure drop at 200 deg C was 1.3 times larger than that at ambient. The change of DF and pressure drop at elevated temperatures was explained by applying Kirsh's theory to elevated temperatures. (author)

Aerosolization of cyanobacterial cells across ecosystem boundaries in the McMurdo Dry Valleys, Antarctica

Science.gov (United States)

Trout-Haney, J.; Heindel, R. C.; Virginia, R. A.

2017-12-01

Cyanobacteria play a major ecological role in polar freshwaters, occurring predominately as small single cells in the water column, i.e., picocyanobacteria, or large multicellular colonies and mats that reside on the lake bottom. Cyanobacteria are also present in terrestrial polar habitats, including within soils, soil crusts, rocks, and glacial ice. Despite their predominance in polar ecosystems, the extent to which cyanobacteria move between terrestrial and aquatic landscape units remains poorly understood. In polar deserts such as the McMurdo Dry Valleys, aeolian processes influence terrestrial landscape morphology and drive the transport of sediments and other particles. Water surfaces can also act as a source of aerosolized particles, such as the production of sea spray aerosols through wave breaking in marine environments. However, aerosolization from freshwater bodies has been far less studied, especially in polar regions. We conducted a field-study to examine the transport of aerosolized cyanobacterial cells from ponds and soils in the McMurdo Dry Valleys. We used highly portable aerosol collection devices fitted with GF/F filters combusted at 500°C (0.3 µm) to collect small particles, such as picocyanobacteria (0.2 - 2 µm), from near-shore water and adjacent soil. We used epifluorescence microscopy to quantify aerosolized cells, with excitation filters for chlorophyll a (435 nm) and phycobilin pigments (572 nm), to distinguish cyanobacterial cells. We detected aerosolized picocyanobacterial cells from all ponds and soils sampled, indicating that these cells may be quite mobile and transported across ecosystem boundaries. We observed cyanobacterial cells individually, clustered, and associated with other organic material, suggesting multiple modes of cell transport. Further, we investigated the potential for aerosolization of toxin-producing cyanobacterial taxa (or unbound cyanotoxins), and the ecological and ecosystem-scale implications of

On the Decay Ratio Determination in BWR Stability Analysis by Auto-Correlation Function Techniques

International Nuclear Information System (INIS)

Behringer, K.; Hennig, D.

2002-11-01

A novel auto-correlation function (ACF) method has been investigated for determining the oscillation frequency and the decay ratio in BWR stability analyses. The neutron signals are band-pass filtered to separate the oscillation peak in the power spectral density (PSD) from background. Two linear second-order oscillation models are considered. These models, corrected for signal filtering and including a background term under the peak in the PSD, are then least-squares fitted to the ACF of the previously filtered neutron signal, in order to determine the oscillation frequency and the decay ratio. Our method uses fast Fourier transform techniques with signal segmentation for filtering and ACF estimation. Gliding 'short-term' ACF estimates on a record allow the evaluation of uncertainties. Numerical results are given which have been obtained from neutron data of the recent Forsmark I and Forsmark II NEA benchmark project. Our results are compared with those obtained by other participants in the benchmark project. The present PSI report is an extended version of the publication K. Behringer, D. Hennig 'A novel auto-correlation function method for the determination of the decay ratio in BWR stability studies' (Behringer, Hennig, 2002)

Fission-nuclide concentrations of ambient aerosol separated by size

International Nuclear Information System (INIS)

Csepregi, T.; Kovacs, L.; Maschek, I.; Szterjopulos, K.

1984-01-01

Examinations were carried on the radionuclides in aerosol deposited on filters of an air-conditioning plant with high air flow rate. For nuclide concentration of ambient air qualitative and quantitative analyses were made by gamma spectrometry. Methods have been developed for sample preparation, size fractionation by sedimentation technique and measurement of air flow. The collected aerosol particles was separated into five size fractions from 1 to 5 μm and the aerosol fractions were analysed. The mass/size distribution of the particles processed by sedimentation has been compared with that of the ambient aerosol separated by a slot impactor Hungarian type. Because the aggregation caused by the resuspensationtechnique would be assumed, electronmicrophotos were made on processed and unprocessed aerosols. On the basis of them the particle aggregation may be negligible. Otherwise, the derivation of concentration needs to know the exact air volume. For this aim the technical parameters of the aerodynamic system have also been measured in two different ways. The paper reports on the size dependence of fission products originating from the present global late fallout for a two years monitoring period. The results are compared with the daily beta activity concentration of aerosol samples taken by an other sampling unit. (Author)

Recirculating electric air filter for use in confined spaces

International Nuclear Information System (INIS)

Bergman, W.; Biermann, A.; Kuhl, W.

1985-01-01

We have developed recirculating electric air filters for use in confined spaces where the existing ventilation system is not adequate for removing suspended particles. Two experimental filters were built and evaluated, both of which consisted of a cylindrical cartridge filter fitted over an air blower. In one design the cylindrical cartridge is a disposable unit with the electrodes and filter medium built as an integrated unit. The second design has a cylindrical cartridge that can be easily disassembled to allow replacement of the filter medium. Both designs were evaluated in a 354-ft 3 test cell using NaCl aerosols. The second design was installed and evaluated in a chamber where highly radioactive 238 PuO 2 powder is formed into pellets. We have derived equations that describe the theory of recirculating air filters. The predicted performance compares well with experimental measurements under controlled conditions. 2 refs., 7 figs., 1 tab. (DT)

Microbial aerosol generation during laboratory accidents and subsequent risk assessment.

Science.gov (United States)

Bennett, A; Parks, S

2006-04-01

To quantify microbial aerosols generated by a series of laboratory accidents and to use these data in risk assessment. A series of laboratory accident scenarios have been devised and the microbial aerosol generated by them has been measured using a range of microbial air samplers. The accident scenarios generating the highest aerosol concentrations were, dropping a fungal plate, dropping a large bottle, centrifuge rotor leaks and a blocked syringe filter. Many of these accidents generated low particle size aerosols, which would be inhaled into the lungs of any exposed laboratory staff. Spray factors (SFs) have been calculated using the results of these experiments as an indicator of the potential for accidents to generate microbial aerosols. Model risk assessments have been described using the SF data. Quantitative risk assessment of laboratory accidents can provide data that can aid the design of containment laboratories and the response to laboratory accidents. A methodology has been described and supporting data provided to allow microbiological safety officers to carry out quantitative risk assessment of laboratory accidents.

Comparison of filter papers and an electrostatic precipitator for measurements on radioactive aerosols

Energy Technology Data Exchange (ETDEWEB)

Wiener, R

1958-06-15

Measurements in which electrostatic precipitators have been compared with filter papers for collection of air-borne radioactivity as to the accuracy in alpha and beta measurements have been made. The results show that the filter paper method is as good as the electrostatic method in determining beta-activity disregarding clogging and moisture sensitivity of the filter paper but it is inferior for alpha measurements. Experimental values of the alpha absorption factor for different types of filter papers are given.

Lidar-measurement of the atmospheric aerosols' extinction based on the field study SAMUM-1; Lidar-Messung der Extinktion des atmosphaerischen Aerosols am Beispiel der Feldstudie SAMUM-1

Energy Technology Data Exchange (ETDEWEB)

Esselborn, Michael

2008-07-01

In the frame of this thesis a high-resolution spectral LIDAR (HSRL) was used for the field study SAMUM during May/June 2006 and January/February 2008 on board of the research aircraft Falcon. The intensity of the LIDAR signals are mainly influences by backscattering and extinction of atmospheric particles (aerosols). Using a narrow-band optical filter the HSRL allows the measurement of the molecular backscattering besides the total atmospheric backscattering. During SAMUM-1 the optical properties of the Sahara dust aerosols were measured for the first time, esp. its extinction, the ratio extinction/backscattering and the depolarization close to the source region. The results of the optical density of the aerosols were compared with satellite-based data. South of the Atlas-mountains optical aerosol densities in the range of 0.50 to 0.60 were measured.

Acid aerosol measurement method intercomparisons: An outdoor smog chamber study

International Nuclear Information System (INIS)

Ellestad, T.G.; Barnes, H.M.; Kamens, R.M.; McDow, S.R.; Sickles, J.E. II; Hodson, L.L.; Waldman, J.M.; Randtke, S.J.; Lane, D.D.; Springston, S.R.; Koutrakis, P.; Thurston, G.D.

1991-01-01

A workshop on the measurement of acid aerosols indicated that the sampling methods in use had not been intercompared. Following two laboratory pilot studies, EPA sponsored tests in an outdoor smog chamber with a variety of test aerosols, including sulfuric acid only, photochemical smog with added sulfuric acid, photo-chemical smog with added sulfuric acid and dust, and dust followed by photochemical smog with added sulfuric acid. Two experiments of each type were conducted. Six groups, several of which were active in ambient acid aerosol measurements, participated by operating duplicate samplers for each experiment. Five groups employed a similar method, in which ammonia is removed from the sample stream by diffusion, particles are removed by Teflon filter, and hydrogen ion on the Teflon filter is determined by pH electrode. However, differences existed in the method's implementation among groups in physical design, flow rate, procedures, and analysis. The sixth group's method did not use a diffusion denuder for ammonia and had several other important differences. Besides hydrogen ion, seven other species were reported by most of the groups, including particle phase sulfate, ammonium, and nitrate, and gas phase sulfur dioxide, ammonia, nitric acid, and nitrous acid. Results of the inter-comparison will be presented

Evaluation of the effect of media velocity on HEPA filter performance

International Nuclear Information System (INIS)

Alderman, Steven; Parsons, Michael; Hogancamp, Kristina; Norton, O. Perry; Waggoner, Charles

2007-01-01

Section FC of the ASME AG-1 Code addresses glass fiber HEPA filters and restricts the media velocity to a maximum of 2.54 cm/s (5 ft/min). Advances in filter media technology allow glass fiber HEPA filters to function at significantly higher velocities and still achieve HEPA performance. However, diffusional capture of particles < 100 nm is reduced at higher media velocities due to shorter residence times within the media matrix. Therefore, it is unlikely that higher media velocities for HEPA filters will be allowed without data to demonstrate the effect of media velocity on removal of particles in the smaller size classes. In order to address this issue, static testing has been conducted to generate performance related data and a range of dynamic testing has provided data regarding filter lifetimes, loading characteristics, changes in filter efficiency and the most penetrating particle size over time. Testing was conducted using 31 cm x 31 cm x 29 cm deep pleat HEPA filters supplied from two manufacturers. Testing was conducted at media velocities ranging from 2.0-4.5 cm/s with a solid aerosol challenge composed of potassium chloride. Two set of media velocity data were obtained for each filter type. In one set of evaluations, the maximum aerosol challenge particle size was limited to 3 μm, while particles above 3 μm were not constrained in the second set. This provided for considerable variability in the challenge mass mean diameter and overall mass loading rate. Results of this testing will be provided to the ASME AG-1 FC Committee for consideration in future versions of the HEPA standard. In general, the initial filter efficiency decreased with increasing media velocity. However, initial filter efficiencies were generally good in all cases. Filter efficiency values averaged over the first ten minute of the loading cycle ranged from 99.970 to 99.996 %. Additionally, the most penetrating particle size was observed to decrease with increasing media velocity

Application of FIGAERO (Filter Inlet for Gases and AEROsol) coupled to a high resolution time of flight chemical ionization mass spectrometer to field and chamber organic aerosol: Implications for carboxylic acid formation and gas-particle partitioning from monoterpene oxidation

Science.gov (United States)

Lopez-Hilfiker, F.; Mohr, C.; Ehn, M.; Rubach, F.; Mentel, T. F.; Kleist, E.; Wildt, J.; Thornton, J. A.

2013-12-01

We present measurements of a large suite of gas and particle phase carboxylic acid containing compounds made with a Filter Inlet for Gas and AEROsol (FIGAERO) coupled to a high resolution time of flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. A prototype operated with acetate negative ion proton transfer chemistry was deployed on the Julich Plant Atmosphere Chamber to study a-pinene oxidation, and a modified version was deployed at the SMEAR II forest station in Hyytiälä, Finland and SOAS, in Brent Alabama. We focus here on results from JPAC and Hyytiälä, where we utilized the same ionization method most selective towards carboxylic acids. In all locations, 100's of organic acid compounds were observed in the gas and particles and many of the same composition acids detected in the gas-phase were detected in the particles upon temperature programmed thermal desorption. Particulate organics detected by FIGAERO are highly correlated with organic aerosol mass measured by an AMS, providing additional volatility and molecular level information about collected aerosol. The fraction of a given compound measured in the particle phase follows expected trends with elemental composition, but many compounds would not be well described by an absorptive partitioning model assuming unity activity coefficients. Moreover the detailed structure in the thermal desorption signals reveals a contribution from thermal decomposition of large molecular weight organics and or oligomers with implications for partitioning measurements and model validation

Development of filter module for passive filtration and accident gas release confinement system for NPP

International Nuclear Information System (INIS)

Yelizarov, P.G.; Efanov, A.D.; Martynov, P.N.; Masalov, D.P.; Osipov, V.P.; Yagodkin, I.V.

2005-01-01

Full text of publication follows: One of the urgent problems of the safe NPP operation is air cleaning from radioactive aerosols and volatile iodine compounds under the accident operation conditions of NPP. A principally new passive accident gas release confinement system is used as the basis of the designs of new generation reactor power blocks under the-beyond-design-basis accident conditions with total loss of current. The basic structural component of the passive filtration system (PFS) is the filter-sorber being heated up to 300 deg. C. The filter-sorber represents a design consisting of 150 connected in parallel two-step filtering modules. The first step is intended to clean air from radioactive aerosols, the second one - to clean air from radioactive iodine and its volatile compounds. The filter-sorber is located in the upper point of the exterior protection shell. Due to natural convection, it provides confinement of r/a impurities and controlled steam-gas release from the inter-shell space into atmosphere. The basic specific design feature is the two-section design of the PFS filter module consisting of a coarse-cleaning section and a fine-cleaning section. A combination of layer-by-layer put filtering materials on the basis of glass fiber and metal fiber. The pilot PFS filter module specimen tests run in conditions modeling accident situation indicated that at a filtration rate of 0,3 cm/s the aerodynamic resistance of the module does not exceed 12 Pa, the filtration effectiveness equals 99,99 % in terms of aerosol, no less than 99,9% in terms of radioactive 131 I and no less than 99,0% in terms of organic compounds of iodine (CH 3 131 I); the dust capacity amounts to a value above 50 g/m 2 . The obtained results of tests comply with the design requirements imposed on the PFS filter-sorber module. (authors)

Characterization of an aerosol sample from the auxiliary building of the Three Mile Island reactor.

Science.gov (United States)

Kanapilly, G M; Stanley, J A; Newton, G J; Wong, B A; DeNee, P B

1983-11-01

Analyses for radioisotopic composition and dissolution characteristics were performed on an aerosol filter sample collected for a week by an air sampler located in the auxiliary building of the Three Mile Island nuclear reactor. The major radioisotopes found on the filter were 89Sr, 90Sr, 134Cs and 137Cs. Greater than 90% of both 89-90Sr and 134-137Cs dissolved within 48 hr in an in vitro test system. Scanning electron microscopic analyses showed the presence of respirable size particles as well as larger particles ranging up to 10 micron in diameter. The major matrix components were Fe, Ca, S, Mg, Al and Si. Although the radionuclides were present in a heterogeneous matrix, they were in a soluble form. This information enables a better evaluation of bioassay data and predictions of dose distribution resulting from an inhalation exposure to this aerosol. Further, the combination of techniques used in this study may be applicable to the characterization of other aerosols of unknown composition.

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

Science.gov (United States)

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

2003-09-15

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

Levels in 223Th populated by α decay of 227U

Science.gov (United States)

Kalaninová, Z.; Antalic, S.; Heßberger, F. P.; Ackermann, D.; Andel, B.; Kindler, B.; Laatiaoui, M.; Lommel, B.; Maurer, J.

2015-07-01

Levels in 223Th populated by the α decay of 227U were investigated using α -γ decay spectroscopy. The 227U isotope was produced in the fusion-evaporation reaction 22Ne +208Pb at the velocity filter separator for heavy-ion reaction products at Gesellschaft für Schwerionenforschung in Darmstadt (Germany). Several new excited levels and γ transitions were identified in 223Th . An improved α -decay scheme of 227U was suggested. The experimental α -decay energy spectrum of 227U was compared with the Monte Carlo simulation performed using the toolkit geant4.

Behavior of radon and its decay products in physical media

International Nuclear Information System (INIS)

Chavez B, A.

1990-06-01

This study was carried out to know the radon behavior, it shows some of its decay products of short life, the same as the equations that describe the growth of the activity of each decay product in a source that initially is radon. The study threw results that they are applicable in geology, uranium prospecting, as well as in radiological safety. The use of membranes to filter the decay products of radon and the use of these for protection of the detector, it has opened a new line in the study of the radon. (Author)

Summary of meeting on disposal of LET ampersand D HEPA filters

International Nuclear Information System (INIS)

1991-01-01

This report is a compilation of correspondence between Westinghouse Idaho Nuclear Company and the US EPA over a period of time from 1988 to 1992 (most from 1991-92) regarding waste management compliance with EPA regulations. Typical subjects include: compliance with satellite accumulation requirements; usage of ''Sure Shot'' containers in place of aerosol cans; notice of upcoming recyclable battery shipments; disposition of batteries; HEPA filter leach sampling and permit impacts; functional and operation requirements for the spent filter handling system; summary of meeting on disposal of LET and D HEPA filters; solvent substitution database report; and mercury vapor light analytical testing

Structural performance of HEPA filters under simulated tornado conditions

International Nuclear Information System (INIS)

Horak, H.L.; Gregory, W.S.; Ricketts, C.I.; Smith, P.R.

1982-02-01

This report contains the results of structural tests to determine the response of High Efficiency Particulate Air filters to simulated tornado conditions. The data include the structural limits of the filters, their resistance at high flow rates, and the effects of filter design features and tornado parameters. Considering all the filters tested, the mean break pressure or structural limit was found to be 2.35 pse (16.2 kPa). The maximum value was 2.87 psi (19.8 kPa), and the low value found was 1.31 psi (9.0 kPa). The type of failure was usually a medium break of the downstream filter fold. The type of filters that were evaluated were nuclear grade with design flow rates of 1000 cfm (0.472 m 3 /s), standard separators, and folded medium design. The parameters evaluated that are characteristic of the filter included manufacturer, separator type, faceguards, pack tightness, and aerosol loading. Manufacturer and medium properties were found to have a large effect on the structural limits

Atmospheric residence times of continental aerosols

International Nuclear Information System (INIS)

Balkanski, Y.J.

1991-01-01

The global atmospheric distributions of Rn-222 are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA Goddard Institute for Space Studies (GISS) general circulation model. The short-lived radioactive gas Rn-222 (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead-210 is produced by decay of Rn-222 and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the Rn-222 distribution. Results from the three-dimensional model are compared to measurements of Rn-222 and Pb-210 atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for Rn-222 are used to examine the long-range transport of continental air over two selected oceanic regions, the subantarctic Indian Ocean and the North Pacific. It is shown that the fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of Pb-210 focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale

Lidar-measurement of the atmospheric aerosols' extinction based on the field study SAMUM-1; Lidar-Messung der Extinktion des atmosphaerischen Aerosols am Beispiel der Feldstudie SAMUM-1

Energy Technology Data Exchange (ETDEWEB)

Esselborn, Michael

2008-07-01

In the frame of this thesis a high-resolution spectral LIDAR (HSRL) was used for the field study SAMUM during May/June 2006 and January/February 2008 on board of the research aircraft Falcon. The intensity of the LIDAR signals are mainly influences by backscattering and extinction of atmospheric particles (aerosols). Using a narrow-band optical filter the HSRL allows the measurement of the molecular backscattering besides the total atmospheric backscattering. During SAMUM-1 the optical properties of the Sahara dust aerosols were measured for the first time, esp. its extinction, the ratio extinction/backscattering and the depolarization close to the source region. The results of the optical density of the aerosols were compared with satellite-based data. South of the Atlas-mountains optical aerosol densities in the range of 0.50 to 0.60 were measured.

Filter-adsorber aging assessment

Energy Technology Data Exchange (ETDEWEB)

Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

1995-02-01

An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission`s (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period.

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles.

Directory of Open Access Journals (Sweden)

Gi Byoung Hwang

Full Text Available Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2(filter at 3-, 6-, and 9-min depositions, respectively. In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97% than for M. luteus aerosols (~95%. High-performance liquid chromatography (HPLC and electrospray ionization-tandem mass spectrometry (ESI/MS analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a

Direct gravimetric determination of aerosol mass concentration in central antarctica.

Science.gov (United States)

Annibaldi, Anna; Truzzi, Cristina; Illuminati, Silvia; Scarponi, Giuseppe

2011-01-01

In Antarctica, experimental difficulties due to extreme conditions have meant that aerosol mass has rarely been measured directly by gravimetry, and only in coastal areas where concentrations were in the range of 1-7 μg m(-3). The present work reports on a careful differential weighing methodology carried out for the first time on the plateau of central Antarctica (Dome C, East Antarctica). To solve problems of accurate aerosol mass measurements, a climatic room was used for conditioning and weighing filters. Measurements were carried out in long stages of several hours of readings with automatic recording of temperature/humidity and mass. This experimental scheme allowed us to sample from all the measurements (up to 2000) carried out before and after exposure, those which were recorded under the most stable humidity conditions and, even more importantly, as close to each other as possible. The automatic reading of the mass allowed us in any case to obtain hundreds of measurements from which to calculate average values with uncertainties sufficiently low to meet the requirements of the differential weighing procedure (±0.2 mg in filter weighing, between ±7% and ±16% both in aerosol mass and concentration measurements). The results show that the average summer aerosol mass concentration (aerodynamic size ≤10 μm) in central Antarctica is about 0.1 μg m(-3), i.e., about 1/10 of that of coastal Antarctic areas. The concentration increases by about 4-5 times at a site very close to the station.

The detection and measurement of the electrical mobility size distributions associated with radon decay products

International Nuclear Information System (INIS)

Fei, Lin.

1996-04-01

The potential risk of lung cancer has evoked interest in the properties of radon decay products. There are two forms of this progeny: either attached to ambient aerosols, or still in the status of ions/molecules/small clusters. This ''unattached'' activity would give a higher dose per unit of airborne activity than the ''attached'' progeny that are rather poorly deposited. In this thesis, a system for determining unattached radon decay products electrical mobility size distribution by measuring their electrical mobilities was developed, based on the fact that about 88% of 218 Po atoms have unit charge at the end of their recoil after decay from 222 Rn, while the remainder are neutral. Essential part of the setup is the radon-aerosol chamber with the Circular Electrical Mobility Spectrometer (CEMS) inside. CEMS is used for sampling and classifying the charged radioactive clusters produced in the chamber. An alpha- sensitive plastic, CR-39 disk, is placed in CEMS as an inlaid disk electrode and the alpha particle detector. CEMS showed good performance in fine inactive particles' classification. If it also works well for radon decay products, it can offer a convenient size distribution measurement for radioactive ultrafine particles. However, the experiments did not obtain an acceptable resolution. Suggestions are made for solving this problem

Evaluation of air samplers and filter materials for collection and recovery of airborne norovirus.

Science.gov (United States)

Uhrbrand, K; Koponen, I K; Schultz, A C; Madsen, A M

2018-04-01

The aim of this study was to identify the most efficient sampling method for quantitative PCR-based detection of airborne human norovirus (NoV). A comparative experiment was conducted in an aerosol chamber using aerosolized murine norovirus (MNV) as a surrogate for NoV. Sampling was performed using a nylon (NY) filter in conjunction with four kinds of personal samplers: Gesamtstaubprobenahme sampler (GSP), Triplex-cyclone sampler (TC), 3-piece closed-faced Millipore cassette (3P) and a 2-stage NIOSH cyclone sampler (NIO). In addition, sampling was performed using the GSP sampler with four different filter types: NY, polycarbonate (PC), polytetrafluoroethylene (PTFE) and gelatine (GEL). The sampling efficiency of MNV was significantly influenced by both sampler and filter type. The GSP sampler was found to give significantly (P airborne NoV. The identification of a suitable NoV air sampler is an important step towards studying the association between exposure to airborne NoV and infection. © 2017 The Society for Applied Microbiology.

Rural continental aerosol properties and processes observed during the Hohenpeissenberg Aerosol Characterization Experiment (HAZE2002

Directory of Open Access Journals (Sweden)

N. Hock

2008-02-01

Full Text Available Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD in Southern Germany.

Online measurements included: Size-resolved chemical composition of submicron particles; total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm; gas-phase concentration of monoterpenes, CO, O₃, OH, and H₂SO₄. Filter sampling and offline analytical techniques were used to determine: Fine particle mass (PM2.5, organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5, and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins.

Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m⁻³, arithmetic mean and standard deviation accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m⁻³. The relative proportions of non-refractory submicron particle components were: (23±39% ammonium nitrate, (27±23% ammonium sulfate, and (50±40% organics (OM1. OM1 was closely correlated with PM1 (r²=0.9 indicating a near-constant ratio of non-refractory organics and inorganics.

The average ratio of OM1 to OC2.5 was 2.1±1.4, indicating a high proportion of heteroelements in the organic fraction of the sampled rural aerosol. This is consistent with the high ratio of oxygenated organic aerosol (OOA over hydrocarbon-like organic aerosol (HOA inferred from the AMS results (4:1, and also with the high abundance of proteins (~3% indicating a high proportion of primary biological material (~30% in PM2.5. This finding was confirmed by low abundance of PAHs (<1 ng m⁻³ and EC (<1 μg m⁻³ in PM2.5 and detection of several

Estimation of the blood velocity spectrum using a recursive lattice filter

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt; Buelund, Claus; Jørgensen, Allan

1996-01-01

acquired for showing the blood velocity distribution are inherently non-stationary, due to the pulsatility of the flow. All current signal processing schemes assume that the signal is stationary within the window of analysis, although this is an approximation. In this paper a recursive least......-stationarity are incorporated through an exponential decay factor, that sets the exponential horizon of the filter. A factor close to 1 gives a long horizon with low variance estimates, but can not track a highly non-stationary flow. Setting the factor is therefore a compromise between estimate variance and the filter...... with the actual distributions that always will be smooth. Setting the exponential decay factor to 0.99 gives satisfactory results for in-vivo data from the carotid artery. The filter can easily be implemented using a standard fixed-point signal processing chip for real-time processing...

Test of methods for retrospective activity size distribution determination from filter samples

International Nuclear Information System (INIS)

Meisenberg, Oliver; Tschiersch, Jochen

2015-01-01

Determining the activity size distribution of radioactive aerosol particles requires sophisticated and heavy equipment, which makes measurements at large number of sites difficult and expensive. Therefore three methods for a retrospective determination of size distributions from aerosol filter samples in the laboratory were tested for their applicability. Extraction into a carrier liquid with subsequent nebulisation showed size distributions with a slight but correctable bias towards larger diameters compared with the original size distribution. Yields in the order of magnitude of 1% could be achieved. Sonication-assisted extraction into a carrier liquid caused a coagulation mode to appear in the size distribution. Sonication-assisted extraction into the air did not show acceptable results due to small yields. The method of extraction into a carrier liquid without sonication was applied to aerosol samples from Chernobyl in order to calculate inhalation dose coefficients for 137 Cs based on the individual size distribution. The effective dose coefficient is about half of that calculated with a default reference size distribution. - Highlights: • Activity size distributions can be recovered after aerosol sampling on filters. • Extraction into a carrier liquid and subsequent nebulisation is appropriate. • This facilitates the determination of activity size distributions for individuals. • Size distributions from this method can be used for individual dose coefficients. • Dose coefficients were calculated for the workers at the new Chernobyl shelter

Evaluation of performance loss of paraffin oil loaded filtering facepieces.

Science.gov (United States)

Tombolini, Francesca; Listrani, Stefano; Campopiano, Antonella; Plebani, Carmela

2016-01-01

Penetration measurements through commercially available filtering facepieces were performed with monodisperse DEHS aerosols ranging from 0.03 μm to 0.40 μm (either singly charged or neutralized), before and after 500 mg of paraffin oil loading. The distinct behavior of Coulomb and polarization capture efficiency is studied: as in the case of non loading also in the case of loading 500 mg of paraffin oil, the electrostatic capture mechanisms are mainly due to the Coulomb contribution up to aerosol particle diameter of about 0.10 μm, just when the polarization contribution becomes substantial. Both Coulomb and polarization capture mechanisms are influenced by the presence of 500 mg of paraffin oil, resulting less effective than the oil unloaded case of about 12% and 11%, respectively. By the occupational hygiene point of view, there is a degradation in the filter performance due to oil loading that the user does not realize because there is no remarkable variation in the breathing resistance.

Particle size for greatest penetration of HEPA filters - and their true efficiency

International Nuclear Information System (INIS)

da Roza, R.A.

1982-01-01

The particle size that most greatly penetrates a filter is a function of filter media construction, aerosol density, and air velocity. In this paper the published results of several experiments are compared with a modern filtration theory that predicts single-fiber efficiency and the particle size of maximum penetration. For high-efficiency particulate air (HEPA) filters used under design conditions this size is calculated to be 0.21 μm diam. This is in good agreement with the experimental data. The penetration at 0.21 μm is calculated to be seven times greater than at the 0.3 μm used for testing HEPA filters. Several mechanisms by which filters may have a lower efficiency in use than when tested are discussed

Development of an automated method for determination of thorium in soil samples and aerosols

International Nuclear Information System (INIS)

Stuart, J.E.; Robertson, R.

1986-09-01

Methodology for determining trace thorium levels in a variety of sample types was further developed. Thorium in filtered water samples is concentrated by ferric hydroxide precipitation followed by dissolution and co-precipitation with lanthanum fluoride. Aerosols on glass fibre, cellulose ester, or teflon filters and solid soil and sediment samples are acid digested. Subsequently thorium is concentrated by lanthanum fluoride co-precipitation. Chemical separation and measurement is then done on a Technicon AA11-C autoanalyzer, using solvent extraction into thenoyltrifuoroacetone in kerosene followed by back extraction into 2 N H NO 3 , and colourometric measurement of the thorium arsenazo III complex. Chemical yields are determined by the addition of thorium-234 tracer using gamma-ray spectrometry. The sensitivities of the methods for water, aerosol and solid samples are approximately 1.0 μg/L, 0.5 μg/g and 1.0 μg/g respectively. At thorium levels about ten times the detection limit, accuracy is estimated to be ± 10% for liquids and aerosols and ± 15% for solid samples, and precision ± 5% for all samples

Charge distribution on plutonium-containing aerosols produced in mixed-oxide reactor fuel fabrication and the laboratory

International Nuclear Information System (INIS)

Yeh, H.C.; Newton, G.J.; Teague, S.V.

1976-01-01

The inhalation toxicity of potentially toxic aerosols may be affected by the electrostatic charge on the particles. Charge may influence the deposition site during inhalation and therefore its subsequent clearance and dose patterns. The electrostatic charge distributions on plutonium-containing aerosols were measured with a miniature, parallel plate, aerosol electrical mobility spectrometer. Two aerosols were studied: a laboratory-produced 238 PuO 2 aerosol (15.8 Ci/g) and a plutonium mixed-oxide aerosol (PU-MOX, natural UO 2 plus PuO 2 , 0.02 Ci/g) formed during industrial centerless grinding of mixed-oxide reactor fuel pellets. Plutonium-238 dioxide particles produced in the laboratory exhibited a small net positive charge within a few minutes after passing through a 85 Kr discharger due to alpha particle emission removal of valence electrons. PU-MOX aerosols produced during centerless grinding showed a charge distribution essentially in Boltzmann equilibrium. The gross alpha aerosol concentrations (960-1200 nCi/l) within the glove box were sufficient to provide high ion concentrations capable of discharging the charge induced by mechanical and/or nuclear decay processes

The uptake of HO2 radicals to organic aerosols

Science.gov (United States)

Matthews, Pascale; Krapf, Manuel; Dommen, Josef; George, Ingrid; Whalley, Lisa; Ingham, Trevor; Baeza-Romero, Maria Teresa; Ammann, Markus; Heard, Dwayne

2014-05-01

HOx (OH + HO2) radicals are responsible for the majority of the oxidation in the troposphere and control the concentrations of many trace species in the atmosphere. There have been many field studies where the measured HO2 concentrations have been smaller than the concentration predicted by model calculations [1,2]. The difference has often been attributed to HO2 uptake by aerosols. Organics are a major component of aerosols accounting for 10 - 70 % of their mass [3]. However, there have been very few laboratory studies measuring HO2 uptake onto organic aerosols [4]. Uptake coefficients (γ) were measured for a range of aerosols using a Fluorescence Assay By Gas Expansion (FAGE) detector combined with an aerosol flow tube. HO2 was injected into the flow tube using a moveable injector which allowed first order HO2 decays to be measured along the flow tube both with and without aerosols. Laboratory generated aerosols were made using an atomiser or by homogeneous nucleation. Secondary organic aerosols (SOA) were made using the Paul Scherrer Institute smog chamber and also by means of a Potential Aerosol Mass (PAM) chamber. The total aerosol surface area was then measured using a Scanning Mobility Particle Sizer (SMPS). Experiments were carried out on aerosols containing glutaric acid, glyoxal, malonic acid, stearic acid, oleic acid and squalene. The HO2 uptake coefficients for these species were measured in the range of γ contained elevated levels of transition metal ions. For humic acid the uptake coefficient was highly dependent on humidity and this may be explained by the liquid water content of the aerosols. Measurements were also performed on copper doped aerosols containing different organics. An uptake coefficient of 0.23 ± 0.07 was measured for copper doped ammonium sulphate, however, this was reduced to 0.008 ± 0.009 when EDTA was added in a 1:1 ratio with copper and 0.003 ± 0.004 when oxalic acid was added in a 10:1 ratio with copper. SOA aerosols were

Structural testing of salt loaded HEPA filters for WIPP

International Nuclear Information System (INIS)

Smith, P.R.; Leslie, I.H.; Hensel, E.C.; Shultheis, T.M.; Walls, J.R.

1993-01-01

The ventilation studies of the Waste Isolation Pilot Plant described in this paper were performed by personnel from New Mexico State Univ. in collaboration with Sandia National Laboratories, Los Alamos National Laboratory and Westinghouse Corporation. High efficiency particulate air filters (0.61m by 0.61m by 0.3m) of the type in use at the Waste Isolation Pilot Plant were loaded with salt aerosol provided from that site. The structural strength of salt-loaded, high-efficiency filters was investigated at two humidity levels, high (75%RH) and low (13-14% RH), by subjecting the filters to pressure transients of the types expected from tornadoes. Filters loaded under the high humidity condition proved to have a greater structural strength than did the filters loaded under the low humidity conditions, when both types were subjected to tornado-like pressure pulses. This unexpected results was apparently due to the crystallization of salt upon the wire face guard of the HEPA filter loaded under the high humidity condition which kept salt from penetrating the filter medium while still providing a substantial pressure drop at the standard flow rate. Results are also presented for HEPA filters pre-conditioned at 100% RH before structural testing and for HEPA filters in series with pre-filters

LMFBR source term experiments in the Fuel Aerosol Simulant Test (FAST) facility

International Nuclear Information System (INIS)

Petrykowski, J.C.; Longest, A.W.

1985-01-01

The transport of uranium dioxide (UO 2 ) aerosol through liquid sodium was studied in a series of ten experiments in the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL). The experiments were designed to provide a mechanistic basis for evaluating the radiological source term associated with a postulated, energetic core disruptive accident (CDA) in a liquid metal fast breeder reactor (LMFBR). Aerosol was generated by capacitor discharge vaporization of UO 2 pellets which were submerged in a sodium pool under an argon cover gas. Measurements of the pool and cover gas pressures were used to study the transport of aerosol contained by vapor bubbles within the pool. Samples of cover gas were filtered to determine the quantity of aerosol released from the pool. The depth at which the aerosol was generated was found to be the most critical parameter affecting release. The largest release was observed in the baseline experiment where the sample was vaporized above the sodium pool. In the nine ''undersodium'' experiments aerosol was generated beneath the surface of the pool at depths varying from 30 to 1060 mm. The mass of aerosol released from the pool was found to be a very small fraction of the original specimen. It appears that the bulk of aerosol was contained by bubbles which collapsed within the pool. 18 refs., 11 figs., 4 tabs

Ozone, spectral irradiance and aerosol measurements with the Brewer spectro radiometer

International Nuclear Information System (INIS)

Marenco, F.; Di Sarra, A.

2001-01-01

In this technical report a detailed description of the Brewer spectro radiometer, a widespread instrument for ozone and ultraviolet radiation, is given. The methodologies used to measure these quantities and for instrument calibration are described in detail. Finally a new methodology, developed by ENEA to derive the aerosol optical depth from the Brewer routine total ozone measurements, is described. This methodology is based on Langley extrapolation, on the determination of the transmissivity of the Brewer neutral density filters, and on a statistically significant number of half days of measurements obtained in could-free conditions. Results of this method, obtained with the Brewer of the ENEA station for climate observations Roberto Sarao, located in the island of Lampedusa, are reported. These results confirm the validity of the method, thanks to independent measurements taken in 1999 with a Multi filter Rotating Shadow band Radiometer. This methodology allows researchers to obtain an aerosol climatology from ozone measurements obtained at several sites world-wide [it

Maritime Aerosol optical properties measured by ship-borne sky radiometer

Science.gov (United States)

Aoki, K.

2017-12-01

Maritime aerosols play an important role in the earth climate change. We started the measurements of aerosol optical properties since 1994 by using ship-borne sky radiometer (POM-01 MK-II and III; Prede Co. Ltd., Japan) over the ocean. We report the results of an aerosol optical properties over the ocean by using Research Vessel of the ship-borne sky radiometers. Aerosol optical properties observation were made in MR10-02 to MR16-09 onboard the R/V Mirai, JAMSTEC. The sky radiometer measure the direct and diffuse solar radiance with seven interference filters (0.315, 0.4, 0.5, 0.675, 0.87, 0.94, and 1.02 µm). Observation interval was made every five minutes by once, only in daytime under the clear sky conditions. GPS provides the position with longitude and latitude and heading direction of the vessel, and azimuth and elevation angle of the sun. The aerosol optical properties were computed using the SKYRAD.pack version 4.2. The obtained Aerosol optical properties (Aerosol optical thickness, Ångström exponent, Single scattering albedo, and etc.) and size distribution volume clearly showed spatial and temporal variability over the ocean. Aerosol optical thickness found over the near the coast (Asia and Tropical area) was high and variable. The size distribution volume have peaks at small particles at Asian coast and large particles at Tropical coast area. We provide the information, in this presentation, on the aerosol optical properties measurements with temporal and spatial variability in the Maritime Aerosol. This project is validation satellite of GCOM-C/SGLI, JAXA and other. The GCOM-C satellite scheduled to be launched in 2017 JFY.

Investigation of the tracers for plastic-enriched waste burning aerosols

Science.gov (United States)

Kumar, Sudhanshu; Aggarwal, Shankar G.; Gupta, Prabhat K.; Kawamura, Kimitaka

2015-05-01

To better identify the tracers for open-waste burning (OWB) aerosols, we have conducted aerosol sampling at 2 landfill sites, i.e., Okhla and Bhalswa in New Delhi. The metals such as, As, Cd, Sb and Sn, which have been observed almost negligible in remote aerosols, are found abundantly in these OWB aerosol samples (n = 26), i.e., 60 ± 65, 41 ± 53, 537 ± 847 and 1325 ± 1218 ng m-3, respectively. Samples (n = 20) collected at urban locations in New Delhi, i.e., at Employees' State Insurance (ESI) hospital and National Physical Laboratory (NPL) also show high abundances of these metals in the particles. Filter samples are also analyzed for water-soluble dicarboxylic acids (C2-C12) and related compounds (oxocarboxylic acids and α-dicarbonyls). Terephthalic acid (tPh) was found to account for more than 77% of total diacids determined in OWB aerosols. However, such a high abundance of tPh is not observed in aerosols collected at urban sites. Instead, phthalic acid (Ph) was found as the third/fourth most abundant diacid (∼3%) following C2 (>70%) and C4 (>12%) in these waste burning influenced urban aerosols. A possible secondary formation pathway of Ph by photo-degradation of phthalate ester (di-2-ethylhexyl phthalate) in plastic-waste burning aerosol is suggested. Ionic composition of OWB aerosols showed that Cl- is the most abundant ion (40 ± 8% of total ions determined). The correlation studies of the potential metals with the organic tracers of garbage burning, i.e., phthalic, isophthalic and terephthalic acids show that especially Sn can be used as marker for tracing the plastic-enriched waste burning aerosols.

Factors Influencing HEPA Filter Performance

International Nuclear Information System (INIS)

Parsons, M.S.; Waggoner, Ch.A.

2009-01-01

Properly functioning HEPA air filtration systems depend on a variety of factors that start with the use of fully characterized challenge conditions for system design and then process control during operation. This paper addresses factors that should be considered during the design phase as well as operating parameters that can be monitored to ensure filter function and lifetime. HEPA filters used in nuclear applications are expected to meet design, fabrication, and performance requirements set forth in the ASME AG-1 standard. The DOE publication Nuclear Air Cleaning Handbook (NACH) is an additional guidance document for design and operation HEPA filter systems in DOE facilities. These two guidelines establish basic maximum operating parameters for temperature, maximum aerosol particle size, maximum particulate matter mass concentration, acceptable differential pressure range, and filter media velocity. Each of these parameters is discussed along with data linking variability of each parameter with filter function and lifetime. Temporal uncertainty associated with gas composition, temperature, and absolute pressure of the air flow can have a direct impact on the volumetric flow rate of the system with a corresponding impact on filter media velocity. Correlations between standard units of flow rate (standard meters per minute or cubic feet per minute) versus actual units of volumetric flow rate are shown for variations in relative humidity for a 70 deg. C to 200 deg. C temperature range as an example of gas composition that, uncorrected, will influence media velocity. The AG-1 standard establishes a 2.5 cm/s (5 feet per minute) ceiling for media velocities of nuclear grade HEPA filters. Data are presented that show the impact of media velocities from 2.0 to 4.0 cm/s media velocities (4 to 8 fpm) on differential pressure, filter efficiency, and filter lifetime. Data will also be presented correlating media velocity effects with two different particle size

Lung delivery of aerosolized dextran.

Science.gov (United States)

Finlay, W H; Lange, C F; King, M; Speert, D P

2000-01-01

The ability of nebulizers to deliver dextran (nominal molecular mass, 4,000 g/mol) to the lung as an inhaled aerosol is evaluated by in vitro experimental methods and mathematical models. Dextran in isotonic saline was aerosolized by four nebulizer types (Pari LC STAR, Hudson T-Updraft II, Acorn II, and Sonix 2000) at dextran concentrations phase Doppler anemometry, filter collection, osmometry, and gravimetry. Mathematical models were used to estimate amounts of the characterized aerosols depositing in the different regions of lung models, and mathematical models of mucous thickness were then developed to estimate initial concentrations of the depositing dextran in the mucus of each conducting airway generation. Models of three subjects (4 yr old, 8 yr old, and adult) were used. The high viscosity of the dextran solutions tested (up to seven times that of water) negatively impacts nebulization, and results in poor performance with most delivery systems tested. Our results suggest that airway mucosal dextran concentrations associated with efficacy in previous animal and in vitro models are achievable with reasonable delivery times (

Seasonal variations of aerosol residence time in the lower atmospheric boundary layer

International Nuclear Information System (INIS)

Ahmed, A.A.; Mohamed, A.; Ali, A.E.; Barakat, A.; Abd El-Hady, M.; El-Hussein, A.

2004-01-01

During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived ( 222 Rn) decay products 214 Pb and 210 Pb. The samples were taken by using a single-filter technique and γ-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214 Pb and 210 Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214 Pb and 210 Pb within the whole year was found to be 1.4±0.27 Bq m -3 and 1.2±0.15 mBq m -3 , respectively. Different 210 Pb: 214 Pb activity ratios during the year varied between 1.78x10 -4 and 1.6x10 -3 with a mean value of 8.9x10 -4 ±7.6x10 -5 . From the ratio between the activity concentrations of the radon decay products 214 Pb and 210 Pb a mean residence time (MRT) of aerosol particles in the atmosphere of about 10.5±0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air

Ventilation and filtration techniques for handling aerosols produced by thermal cutting operations

International Nuclear Information System (INIS)

Bishop, A.

1989-01-01

This report describes the work done to characterize aerosols from thermal cutting operations and to develop suitable ventilation and filtration techniques. The work has been carried out under a research contract between the Windscale Laboratory and the Commission of the European Communities. The contract started in October 1984 and was completed in June 1988. The total cost of the work was UKL 132 000 of which 50% was funded by the Commission. This report has been compiled from the several progress reports submitted during the work period and details the main findings from the work programme. By working with colleagues from Commissariat a l'energie atomique, Saclay, France, additional useful data were collected. The bimodal size distribution of aerosols from oxypropane cutting was confirmed. Trials on various prefilters showed that the electrostatic precipitator (ESP) and the cartridge filter had excellent collection properties. From these trials the ESP was selected as the prefilter for the windscale advanced gas-cooled reactor (WAGR) decommissioning project. This work is presented in Appendix 1 to this report. Details are given of the proposals to modify the ESP to enable the safe removal of radioactive dust and contamined collector plates. Tests are described on aerosols generated by laser cutting and also trials on the ESP and high gradient magnetic separation prefilters. Finally, the measurement of filter burdens, aerosol concentrations and dust deposition rates from thermal cutting in a full-size ventilation rig are reported

Preliminary Design of Molecular Sieve for Removing Organic Iodide in Containment Filtered Venting System

Energy Technology Data Exchange (ETDEWEB)

Park, Tong Kyu; Shin, So Eun; Lee, Byung Chul [Heungdeok IT Valley Bldg., Yongin (Korea, Republic of); Kim, Hong Hyun; Lee, Kyung Jun [Gemvax and KAEL Inc., Daejeon (Korea, Republic of)

2014-05-15

In this paper, to increase the DF for gaseous iodine species, especially organic iodide, molecular sieve filled by silver exchanged zeolites is proposed and designed preliminarily. Its aerodynamic analysis is also performed and presented. In order to increase the DF for gaseous organic iodide, deep-bed type molecular sieve was proposed and designed preliminarily. Total 1,620kg of silver exchanged zeolites were filled evenly in 10 beds of the molecular sieve. The safety factor in the case of 20m{sup 3}/s will be smaller than the counterpart of the standard case (6m{sup 3}/s). However, if the adsorption capacity of the zeolites is larger than 3.09mg/g when the residence time is 0.09 second, the designed molecular sieve can be used at 20m3/s of volumetric flow rate. The removal efficiency for organic iodide should be considered as well as economical aspects in the design of molecular sieve. In the event of nuclear power plant (NPP) severe accident, the nuclear reactor containment might suffer damage resulting from overpressure caused by decay heat. In order to prevent this containment damage, containment venting has been considered as one of effective methods. However, since vented gases contain radioactive fission products, they should be filtered to be released to environment. Generally, containment filtered venting system (CFVS) is installed on NPP to achieve this aim. Even though great amount of efforts have been devoted to developing the CFVS using various filtering methods, the decontaminant factor (DF) for radioactive gaseous iodide is still unsatisfactory while DFs for radioactive aerosols and elemental iodine are very high.

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.

Atmospheric Residence Times of Continental Aerosols.

Science.gov (United States)

Balkanski, Yves Jacques

The global atmospheric distributions of ^{222}Rn and ^{210 }Pb are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA GISS^1>=neral circulation model. The short-lived radioactive gas ^ {222}Rn (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead -210 is produced by decay of ^{222} Rn and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the ^{222} Rn distribution. Results from the three-dimensional model are compared to measurements of ^ {222}Rn and ^{210 }Pb atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for ^{222} Rn are used to examine the long-range transport of continental air over two selected oceanic regions, the subantartic Indian Ocean and the North Pacific. It is shown that fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of ^{210}Pb focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale. The globally averaged residence time for ^{210 }Pb-containing aerosols in the troposphere is 7 days. The average increase in residence time

Light absorption of secondary organic aerosol: Composition and contribution of nitro-aromatic compounds

Science.gov (United States)

Secondary organic aerosol (SOA) might affect the atmospheric radiation balance through absorbing light at shorter visible and UV wavelengths. However, the composition and optical properties of light-absorbing SOA is poorly understood. In this work, SOA filter samples were collect...

Aerosol Sampling System for Collection of Capstone Depleted Uranium Particles in a High-Energy Environment

International Nuclear Information System (INIS)

Holmes, Thomas D.; Guilmette, Raymond A.; Cheng, Yung-Sung; Parkhurst, MaryAnn; Hoover, Mark D.

2009-01-01

The Capstone Depleted Uranium Aerosol Study was undertaken to obtain aerosol samples resulting from a kinetic-energy cartridge with a large-caliber depleted uranium (DU) penetrator striking an Abrams or Bradley test vehicle. The sampling strategy was designed to (1) optimize the performance of the samplers and maintain their integrity in the extreme environment created during perforation of an armored vehicle by a DU penetrator, (2) collect aerosols as a function of time post-impact, and (3) obtain size-classified samples for analysis of chemical composition, particle morphology, and solubility in lung fluid. This paper describes the experimental setup and sampling methodologies used to achieve these objectives. Custom-designed arrays of sampling heads were secured to the inside of the target in locations approximating the breathing zones of the vehicle commander, loader, gunner, and driver. Each array was designed to support nine filter cassettes and nine cascade impactors mounted with quick-disconnect fittings. Shielding and sampler placement strategies were used to minimize sampler loss caused by the penetrator impact and the resulting fragments of eroded penetrator and perforated armor. A cyclone train was used to collect larger quantities of DU aerosol for chemical composition and solubility. A moving filter sample was used to obtain semicontinuous samples for depleted uranium concentration determination. Control for the air samplers was provided by five remotely located valve control and pressure monitoring units located inside and around the test vehicle. These units were connected to a computer interface chassis and controlled using a customized LabVIEW engineering computer control program. The aerosol sampling arrays and control systems for the Capstone study provided the needed aerosol samples for physicochemical analysis, and the resultant data were used for risk assessment of exposure to DU aerosol

Interpretation of aerosol trace metal particle size distributions

International Nuclear Information System (INIS)

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

1974-01-01

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

Development of Methodologies from Determination of Organic Components from Atmospheric Aerosol; Desarrollo de Metodologias para la Determinacion de Componentes Organicos del Aerosol Atmosferico

Energy Technology Data Exchange (ETDEWEB)

Pindado, O; Perez, R; Garcia, R; Barrado, A I; Sevillano, M L; Gonzalez, D

2006-07-01

It is presented method for the organic compound determination, such as n-alkanes, PAH's, alcohols and fatty acids that are comprised the particulate matter of aerosol. The procedure is based on sampling the particulate matter over quartz fibre filters that will be extracted by means of the Soxhiet technique, and later they will be divided by means of silicagel column. PAH's is analyzed by means of HPLCm whereas the rest is analyzed by GC-MS and for it, acids and alcohol must be previously derivatized with BSTFA.12 samples took shelter of fractions PMIO and PM2.5 of the aerosol of country side like application of the method. (Author) 60 refs.

Development of Methodologies from Determination of Organic Components from Atmospheric Aerosol; Desarrollo de Metodologias para la Determinacion de Componentes Organicos del Aerosol Atmosferico

Energy Technology Data Exchange (ETDEWEB)

Pindado, O.; Perez, R.; Garcia, R.; Barrado, A. I.; Sevillano, M. L.; Gonzalez, D.

2006-07-01

It is presented method for the organic compound determination, such as n-alkanes, PAH's, alcohols and fatty acids that are comprised the particulate matter of aerosol. The procedure is based on sampling the particulate matter over quartz fibre filters that will be extracted by means of the Soxhiet technique, and later they will be divided by means of silicagel column. PAH's is analyzed by means of HPLCm whereas the rest is analyzed by GC-MS and for it, acids and alcohol must be previously derivatized with BSTFA.12 samples took shelter of fractions PMIO and PM2.5 of the aerosol of country side like application of the method. (Author) 60 refs.

Ghost suppression in image restoration filtering

Science.gov (United States)

Riemer, T. E.; Mcgillem, C. D.

1975-01-01

An optimum image restoration filter is described in which provision is made to constrain the spatial extent of the restoration function, the noise level of the filter output and the rate of falloff of the composite system point-spread away from the origin. Experimental results show that sidelobes on the composite system point-spread function produce ghosts in the restored image near discontinuities in intensity level. By redetermining the filter using a penalty function that is zero over the main lobe of the composite point-spread function of the optimum filter and nonzero where the point-spread function departs from a smoothly decaying function in the sidelobe region, a great reduction in sidelobe level is obtained. Almost no loss in resolving power of the composite system results from this procedure. By iteratively carrying out the same procedure even further reductions in sidelobe level are obtained. Examples of original and iterated restoration functions are shown along with their effects on a test image.

Lattice Boltzmann model for three-dimensional decaying homogeneous isotropic turbulence

International Nuclear Information System (INIS)

Xu Hui; Tao Wenquan; Zhang Yan

2009-01-01

We implement a lattice Boltzmann method (LBM) for decaying homogeneous isotropic turbulence based on an analogous Galerkin filter and focus on the fundamental statistical isotropic property. This regularized method is constructed based on orthogonal Hermite polynomial space. For decaying homogeneous isotropic turbulence, this regularized method can simulate the isotropic property very well. Numerical studies demonstrate that the novel regularized LBM is a promising approximation of turbulent fluid flows, which paves the way for coupling various turbulent models with LBM

Intermediate results of a one-year study of a laser spectrometer in the DOE filter test facilities

International Nuclear Information System (INIS)

Soderholm, S.C.; Tillery, M.I.

1984-01-01

A 1-year study of the model LAS-X (Particle Measuring Systems, Inc.) laser spectrometer in the Department of Energy (DOE) Filter Test Facilities (FTFs) was begun on August 1, 1983. The principal objectives of the study were to gain operational experience with the LAS-X/diluter/HP-85 particle size measurement system in the FTF environment, acquire size distribution data to quantify the consistency of the Q107 aerosol size distribution at each FTF and among FTFs, and compare the FTF test aerosols to current and proposed standards. Results of the first 9 months of the study are summarized and discussed. Major conclusions based on these data are: (1) the LAS-X system can be operated successfully in the FTF environment, (2) each FTF would require a back-up LAS-X to be able to continue filter testing during the (at least) once each year removal of a LAS-X from service for major recalibration and repair, (3) the FTF test aerosols are not monodisperse, as assumed in the military standard MIL-STD-282, and do not all meet the new DOE Nuclear Standard NE-F-3-43, which a replacement aerosol would be required to meet, (4) the test aerosol at each FTF is quite consistent over time, and (5) the test aerosols at the three FTFs differ consistently. Final conclusions and recommendations from this study will be developed after analysis of the full 12 months of data

Concentration of elements in atmospheric aerosol in Bratislava

International Nuclear Information System (INIS)

Meresova, J.; Florek, M.; Holy, K.; Sykora, I.; Frontasyeva, M.V.; Pavlov, S.S.

2006-01-01

The concentrations of 41 chemical elements (heavy metals, rare earths, and actinides) were determined in atmospheric aerosol using nuclear and related analytical techniques. The sampling location in Bratislava (Slovak Republic). The main goal of this study is the quantification of the atmospheric pollution and its trend. The elemental content in filters was measured using instrumental neutron activation analysis at IBR-2 reactor in JINR Dubna and by atomic absorption spectrometry in Bratislava. The obtained results confirm the decreasing trend of pollution by most of the heavy metals in Bratislava atmosphere, and they are compared with the contents of pollutants in atmosphere of other cities. We determined also the composition of clear filter materials. (Authors)

Hydrodynamic calculation of a filter sand bed type used in the containment venting systems

International Nuclear Information System (INIS)

Cuevas V, D.; Sainz M, E.; Ortiz V, J.

2015-09-01

The filtered venting of the containment has been adopted in European countries to mitigate the consequences of excess pressure containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter on the same path is placed, so that various types of filters are used to trap the fission products. The venting filters of the containment currently installed use different filtration technologies that involve more than one medium. Those using water as the first stage of filtration are called wet systems and are equipped with additional steps to remove water drops and fine aerosols emissions. And even they may also be equipped with an element containing certain absorption means for the filtration of gaseous iodine species. Other designs based on filtration of deep bed as the primary retention step; called dry filters, use filtration media of metal fiber, ceramic or sand to trap aerosols. This paper evaluates the hydraulic characteristics of the filter sand bed type designed by EDF as a candidate to be installed in the containment of BWR Mark II (type of primary containment of the nuclear power plant of Laguna Verde). The evaluation of filter sand bed type was performed using the software package of open source OpenFOAM. Models of each zone of the filtered device were generated and through a series of parametric calculations of computational fluid mechanics relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow rate and pressure fields and speed at different operating conditions. On the other hand, the model validation of the sand bed filter when comparing the results of experimental tests on a sand column of PITEAS program (1985-1986) against OpenFOAM simulation was realized. The results are very close to those obtained experimentally. (Author)

Assessment of microphysical and chemical factors of aerosols over seas of the Russian Artic Eastern Section

Science.gov (United States)

Golobokova, Liudmila; Polkin, Victor

2014-05-01

The newly observed kickoff of the Northern Route development drew serious attention to state of the Arctic Resource environment. Occurring climatic and environmental changes are more sensitively seen in polar areas in particular. Air environment control allows for making prognostic assessments which are required for planning hazardous environmental impacts preventive actions. In August - September 2013, RV «Professor Khlustin» Northern Sea Route expeditionary voyage took place. En-route aerosol sampling was done over the surface of the Beringov, Chukotka and Eastern-Siberia seas (till the town of Pevek). The purpose of sampling was to assess spatio-temporal variability of optic, microphysical and chemical characteristics of aerosol particles of the surface layer within different areas adjacent to the Northern Sea Route. Aerosol test made use of automated mobile unit consisting of photoelectric particles counter AZ-10, aetalometr MDA-02, aspirator on NBM-1.2 pump chassis, and the impactor. This set of equipment allows for doing measurements of number concentration, dispersed composition of aerosols within sizes d=0.3-10 mkm, mass concentration of submicron sized aerosol, and filter-conveyed aerosols sampling. Filter-conveyed aerosols sampling was done using method accepted by EMEP and EANET monitoring networks. The impactor channel was upgraded to separate particles bigger than 1 mkm in size, and the fine grain fraction settled down on it. Reverse 5-day and 10-day trajectories of air mass transfer executed at heights of 10, 1500 and 3500 m were analyzed. The heights were selected by considerations that 3000 m is the height which characterizes air mass trend in the lower troposphere. 1500 m is the upper border of the atmospheric boundary layer, and the sampling was done in the Earth's surface layer at less than 10 m. Minimum values of the bespoken microphysical characteristics are better characteristic of higher latitudes where there are no man induced sources of

GENERATION, TRANSPORT AND DEPOSITION OF TUNGSTEN-OXIDE AEROSOLS AT 1000 C IN FLOWING AIR-STEAM MIXTURES.

Energy Technology Data Exchange (ETDEWEB)

GREENE,G.A.; FINFROCK,C.C.

2001-10-01

Experiments were conducted to measure the rates of oxidation and vaporization of pure tungsten rods in flowing air, steam and air-steam mixtures in laminar flow. Also measured were the downstream transport of tungsten-oxide condensation aerosols and their region of deposition, including plateout in the superheated flow tube, rainout in the condenser and ambient discharge which was collected on an array of sub-micron aerosol filters. The nominal conditions of the tests, with the exception of the first two tests, were tungsten temperatures of 1000 C, gas mixture temperatures of 200 C and wall temperatures of 150 C to 200 C. It was observed that the tungsten oxidation rates were greatest in all air and least in all steam, generally decreasing non-linearly with increasing steam mole fraction. The tungsten oxidation rates in all air were more than five times greater than the tungsten oxidation rates in all steam. The tungsten vaporization rate was zero in all air and increased with increasing steam mole fraction. The vaporization rate became maximum at a steam mole fraction of 0.85 and decreased thereafter as the steam mole fraction was increased to unity. The tungsten-oxide was transported downstream as condensation aerosols, initially flowing upwards from the tungsten rod through an 18-inch long, one-inch diameter quartz tube, around a 3.5-inch radius, 90{sup o} bend and laterally through a 24-inch horizontal run. The entire length of the quartz glass flow path was heated by electrical resistance clamshell heaters whose temperatures were individually controlled and measured. The tungsten-oxide plateout in the quartz tube was collected, nearly all of which was deposited at the end of the heated zone near the entrance to the condenser which was cold. The tungsten-oxide which rained out in the condenser as the steam condensed was collected with the condensate and weighed after being dried. The aerosol smoke which escaped the condenser was collected on the sub

Aerosol composition and source apportionment in Santiago de Chile

International Nuclear Information System (INIS)

Artaxo, Paulo; Oyola, Pedro; Martinez, Roberto

1999-01-01

Santiago de Chile, Sao Paulo and Mexico City are Latin American urban areas that suffer from heavy air pollution. In order to study air pollution in Santiago area, an aerosol source apportionment study was designed to measure ambient aerosol composition and size distribution for two downtown sampling sites in Santiago. The aerosol monitoring stations were operated in Gotuzo and Las Condes during July and August 1996. The study employed stacked filter units (SFU) for aerosol sampling, collecting fine mode aerosol (dp 10 mass of particles smaller than 10 μm) and black carbon concentration were also measured. Particle-Induced X-ray Emission (PIXE) was used to measure the concentration of 22 trace elements at levels below 0.5 ng m -3 . Quantitative aerosol source apportionment was performed using Absolute Principal Factor Analysis (APFA). Very high aerosol concentrations were observed (up to 400 μg/m 3 PM 10 ). The main aerosol particle sources in Santiago are resuspended soil dust and traffic emissions. Coarse particles account for 63% of PM 10 aerosol in Gotuzo and 53% in Las Condes. A major part of this component is resuspended soil dust. In the fine fraction, resuspended soil dust accounts for 15% of fine mass, and the aerosols associated with transportation activities account for a high 64% of the fine particle mass. Sulfate particle is an important component of the aerosol in Santiago, mainly originating from gas-to-particle conversion from SO 2 . In the Gotuzo site, sulfates are the highest aerosol component, accounting for 64.5% of fine mass. Direct traffic emissions are generally mixed with resuspended soil dust. It is difficult to separate the two components, because the soil dust in downtown Santiago is contaminated with Pb, Br, Cl, and other heavy metals that are also tracers for traffic emissions. Residual oil combustion is observed, with the presence of V, S and Ni. An aerosol components from industrial emissions is also present, with the presence of

Chemical and isotopic composition of secondary organic aerosol generated by α-pinene ozonolysis

DEFF Research Database (Denmark)

Meusinger, Carl; Dusek, Ulrike; King, Stephanie M.

2017-01-01

-NOx conditions, with OH scavengers and in the absence of seed particles. The excess of ozone and long residence time in the flow chamber ensured that virtually all α-pinene had reacted. Product SOA was collected on two sequential quartz filters. The filters were analysed offline by heating them stepwise from 100...... it is difficult to apply because neither the isotopic composition of aerosol precursors nor the fractionation of aerosol forming processes is well characterised. In this paper, SOA formation from ozonolysis of α-pinene - an important precursor and perhaps the best-known model system used in laboratory studies...... - was investigated using position-dependent and average determinations of 13C in α-pinene and advanced analysis of reaction products using thermal-desorption proton-transfer-reaction mass spectrometry (PTR-MS). The total carbon (TC) isotopic composition δ13C of the initial α-pinene was measured, and the δ13C...

Evidence for and implications of self-background of radon dosimeters with glass-fiber filters

International Nuclear Information System (INIS)

Put, L.W.; Lembrechts, J.; Graaf, E.R. van der; Stoop, P.

2000-01-01

The first national radon survey in the Netherlands was conducted in 1984 with passive radon dosimeters that contain glass-fiber diffusion filters. During the last few years, measurements of outdoor-radon concentrations and information in the literature suggested that these dosimeters may give falsely elevated readings. A systematic contribution would be present due to alpha particles from natural radionuclides in the glass-fiber filter producing tracks on the track-etch foil. In the framework of the quality assurance of their laboratories, the origin of this offset was systematically assessed by means of measurements of alpha and gamma radiation from the glass-fiber filters and by intercomparisons between different types of detectors at low radon concentrations. It was found that alpha particles from the decay of 214 Po in the glass-fiber filter are the main cause of the extra tracks (only 12% originates from decay of 212 Po), leading, for this type of filter, to an offset in concentration of approximately 8 Bq m -3 . The implications of this offset are discussed

A mini-sampler for welding aerosol mounted in close vicinity of the mouth/nose

International Nuclear Information System (INIS)

Liden, Goeran; Surakka, Jouni

2009-01-01

A small personal aerosol mini-sampler to be used inside modern welding visors has been developed. The main object of the mini-sampler has been to sample manganese. The sampler is based on commercially available 13 mm filter holders but modified to incorporate an inlet nozzle made of aluminium. The nominal flow rate of the mini-sampler is 0,75 l/min. The sampler is to be worn mounted on a headset, modified from professional microphone headsets. The headset mounting arrangement was accepted by the welders. The sampling bias of the mini sampler versus the IOM sampler depends on the coarseness of the sampled aerosol. At the lowest concentration ratio of the open-face 25 mm filter holder to the IOM sampler equal to 0,65, the bias of the mini sampler is approximately -26% versus the IOM. The RMS sampling bias of the mini sampler versus the IOM sampler for manganese is -4,6%. The inhalable fraction of welding aerosol mass consists only of 25-55% of welding fume. The rest of the mass is made up of spatter particles and grinding particles. For manganese generally more than 65% is found in the fume.

Characterization of a Head-Only Aerosol Exposure System for Nonhuman Primates

Science.gov (United States)

2010-01-01

Alicat Scientific). The flow used provided isokinetic sampling, assuming the presence of laminar flow at the filter inlet, so that the chamber...airflow measured at the chamber inlet using a Gilibrator flow meter (Sensidyne LP) was 29.79±0.88L/min (n= 10; CV=2.97%). With both the aerosol

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�

Evaluation of the Performance of Iodine-Treated Biocide Filters Challenged with Bacterial Spores and Viruses

National Research Council Canada - National Science Library

Lee, Jin-Hwa; Wu, Chang-Yu

2006-01-01

Filter media coated with a cationic resin in triiodide form were challenged by Bacillus subtilis spores and MS2 bacteriophage aerosols delivered from a Collison nebulizer through air at 35% RH and 23 C...

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

Aerosol typing is a key source of aerosol information from ground-based and satellite-borne instruments. Depending on the specific measurement technique, aerosol typing can be used as input for retrievals or represents an output for other applications. Typically aerosol retrievals require some a priori or external aerosol type information. The accuracy of the derived aerosol products strongly depends on the reliability of these assumptions. Different sensors can make use of different aerosol type inputs. A critical review and harmonization of these procedures could significantly reduce related uncertainties. On the other hand, satellite measurements in recent years are providing valuable information about the global distribution of aerosol types, showing for example the main source regions and typical transport paths. Climatological studies of aerosol load at global and regional scales often rely on inferred aerosol type. There is still a high degree of inhomogeneity among satellite aerosol typing schemes, which makes the use different sensor datasets in a consistent way difficult. Knowledge of the 4d aerosol type distribution at these scales is essential for understanding the impact of different aerosol sources on climate, precipitation and air quality. All this information is needed for planning upcoming aerosol emissions policies. The exchange of expertise and the communication among satellite and ground-based measurement communities is fundamental for improving long-term dataset consistency, and for reducing aerosol type distribution uncertainties. Aerosol typing has been recognized as one of its high-priority activities of the AEROSAT (International Satellite Aerosol Science Network, http://aero-sat.org/) initiative. In the AEROSAT framework, a first critical review of aerosol typing procedures has been carried out. The review underlines the high heterogeneity in many aspects: approach, nomenclature, assumed number of components and parameters used for the

The in-situ testing of high efficiency particulate filters in the CEGB south eastern region nuclear power stations

International Nuclear Information System (INIS)

Powell, A.W.; Wilkinson, B.A.

1977-01-01

High efficiency air filters are installed in the CEGB's Nuclear Power Stations to prevent discharge of radioactive material to the environment should the ventilation air become contaminated. The Board has determined that these filter units should be tested in-situ to ensure that the stringent design specifications are met. This paper describes the rig work comparing the British Standard method using sodium chloride aerosol with other test methods, such as Dioctyl Phthalate, naturally occurring dust aerosols and artificially produced condensation nuclei. This work led to the development of an in-situ test method using condensation nuclei and a Pollak-Nolan nucleus counter. The advantages and disadvantages of this method over other methods for in-situ testing is discussed. The test method has been used in the South Eastern Region for several years and considerable experience has been gained in its use on a wide variety of filter systems. The method adopted for each system is detailed including the injection, sampling and interpretation of the results obtained. Numerous faults and difficulties have been highlighted from the design, installation and filter changing aspects

Broadband optical properties of biomass-burning aerosol and identification of brown carbon chromophores: OPTICAL AND CHEMICAL PROPERTIES OF BROWN CARBON AEROSOLS

Energy Technology Data Exchange (ETDEWEB)

Bluvshtein, Nir [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Lin, Peng [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; Flores, J. Michel [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Segev, Lior [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Mazar, Yinon [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Tas, Eran [The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot Israel; Snider, Graydon [Department of Physics and Atmospheric Science, Dalhousie University, Halifax Nova Scotia Canada; Weagle, Crystal [Department of Chemistry, Dalhousie University, Halifax Nova Scotia Canada; Brown, Steven S. [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder Colorado USA; Laskin, Alexander [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; Rudich, Yinon [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel

2017-05-23

The radiative effects of biomass burning aerosols on regional and global scale is substantial. Accurate modeling of the radiative effects of smoke aerosols require wavelength-dependent measurements and parameterizations of their optical properties in the UV and visible spectral ranges along with improved description of their chemical composition. To address this issue, we used a recently developed approach to retrieve the time- and spectral-dependent optical properties of ambient biomass burning aerosols between 300 and 650 nm wavelength during a regional bonfire festival in Israel. During the biomass burning event, the overall absorption at 400 nm increased by about two orders of magnitude, changing the size-weighted single scattering albedo from a background level of 0.95 to 0.7. Based on the new retrieval method, we provide parameterizations of the wavelength-dependent effective complex refractive index from 350 to 650 nm for freshly emitted and aged biomass burning aerosols. In addition, PM2.5 filter samples were collected for detailed off-line chemical analysis of the water soluble organics that contribute to light absorption. Nitrophenols were identified as the main organic species responsible for the increased absorption at 400-500 nm. These include species such as 4- nitrocatechol, 4-nitrophenol, nitro-syringol and nitro-guaiacol; oxidation-nitration products of methoxyphenols, known products of lignin pyrolysis. Our findings emphasize the importance of both primary and secondary organic aerosol from biomass burning in absorption of solar radiation and in effective radiative forcing.

Aerosol sampling and characterization for hazard evaluation. Progress report, July 1, 1975--September 30, 1976

International Nuclear Information System (INIS)

Scripsick, R.C.; Gray, D.C.; Tillery, M.I.; Stafford, R.G.; Romero, P.O.

1977-04-01

A draft Manual of Recommended Practice for Aerosol Sampling and Evaluation was completed and sent to the Energy Research and Development Administration (ERDA) Division of Safety, Standards, and Compliance (DSSC) for review. The results of the Survey of Sampling Techniques for Defining Respirable Concentration and/or Particle Size Characteristics of Aerosols were published as LA-6087. The need for greater standardization of ERDA aerosol sampling techniques was indicated. The Aerosol Training Course was presented in 11 sessions to 85 persons. General elements of good practice were emphasized, and recommendation of specific sampling devices or procedures was avoided. A system for estimating dissolution rates of plutonium aerosols was developed. Studies indicate that plutonium aerosols found in the field have a rapid initial dissolution phase followed by a slower secondary phase. Three methods of particle sizing air samples collected on membrane filters were investigated. The most promising was a scanning electron microscope electron microprobe (SEM-EMp) method. An operating plutonium handling facility was a model for development of techniques to evaluate aerosol surveillance systems performance. Airborne contamination records were studied. The physicochemical properties of a plutonium aerosol existing in the facility were investigated in relation to plutonium handling operations. The techniques developed have indicated some areas of the aerosol surveillance system that need improvement

Measurement of filtration efficiency of Nuclepore filters challenged with polystyrene latex nanoparticles: experiments and modeling

International Nuclear Information System (INIS)

Ling, Tsz Yan; Wang Jing; Pui, David Y. H.

2011-01-01

Membrane filtration has been demonstrated to be effective for the removal of liquid-borne nanoparticles (NPs). Such technique can be applied to purify and disinfect drinking water as well as remove NPs in highly pure chemicals used in the industries. This study aims to study the filtration process of a model membrane filter, the Nuclepore filter. Experiments were carried out using standard filtration tools and the nanoparticle tracking analysis (NTA) technique was used to measure particle (50–500 nm) concentration upstream and downstream of the filter to determine the filtration efficiency. The NTA technique has been calibrated using 150-nm polystyrene latex particles to determine its accuracy of particle concentration measurement. Measurements were found reliable within a certain concentration limit (about 10 8 –10 10 particles/cm 3 ), which is dependent on the camera settings during the measurement. Experimental results are comparable with previously published data obtained using the aerosolization method, validating the capability of the NTA technique. The capillary tube model modified from that developed for aerosol filtration was found to be useful to represent the experimental results, when a sticking coefficient of 0.15 is incorporated. This suggests that only 15% of the particle collisions with the filter results in successful attachment. The small sticking coefficient found can be explained by the unfavorable surface interactions between the particles and the filter medium.

Improvements in in-situ filter test methods using a total light-scattering detector

International Nuclear Information System (INIS)

Marshall, M.; Stevens, D.C.

1986-01-01

This paper presents research aimed at providing useful data on a commonly used technique; a DOP (di-2-ethylhexyl phthalate) aerosol and a total light-scattering photometer. Methods of increasing the sensitivity of this technique are described. Alternative methods of in-situ filter testing are also considered. The sensitivity of a typical, modern, total light-scattering photometer, as a function of particle diameter, has a broad maximum in mass terms between 0.1 and 0.4 um. At its maximum usable sensitivity the instrument can detect approx. 1 particle/cm 3 . This response can be explained by light scattering theory and particle loss in the instrument inlet. The mass median diameter of the aerosols produced by various DOP generators varies from 0.2 to 1.0μm. Experiments with good quality HEPA filters indicate a maximum penetration for particles of 0.15 - 0.2μm. Details of the studies are given and the consequences discussed. It is shown that filter penetration of -3 % can be measured in-situ with existing equipment. Methods of extending the sensitivity to measure a penetration of approx.10 -5 % are described. (author)

A Novel Method and Its Application to Measuring Pathogen Decay in Bioaerosols from Patients with Respiratory Disease.

Directory of Open Access Journals (Sweden)

Graham R Johnson

Full Text Available This work aimed to develop an in vivo approach for measuring the duration of human bioaerosol infectivity. To achieve this, techniques designed to target short-term and long-term bioaerosol aging, were combined in a tandem system and optimized for the collection of human respiratory bioaerosols, without contamination. To demonstrate the technique, cough aerosols were sampled from two persons with cystic fibrosis and chronic Pseudomonas aeruginosa infection. Measurements and cultures from aerosol ages of 10, 20, 40, 900 and 2700 seconds were used to determine the optimum droplet nucleus size for pathogen transport and the airborne bacterial biological decay. The droplet nuclei containing the greatest number of colony forming bacteria per unit volume of airborne sputum were between 1.5 and 2.6 μm. Larger nuclei of 3.9 μm, were more likely to produce a colony when impacted onto growth media, because the greater volume of sputum comprising the larger droplet nuclei, compensated for lower concentrations of bacteria within the sputum of larger nuclei. Although more likely to produce a colony, the larger droplet nuclei were small in number, and the greatest numbers of colonies were instead produced by nuclei from 1.5 to 5.7 μm. Very few colonies were produced by smaller droplet nuclei, despite their very large numbers. The concentration of viable bacteria within the dried sputum comprising the droplet nuclei exhibited an orderly dual decay over time with two distinct half-lives. Nuclei exhibiting a rapid biological decay process with a 10 second half-life were quickly exhausted, leaving only a subset characterized by a half-life of greater than 10 minutes. This finding implied that a subset of bacteria present in the aerosol was resistant to rapid biological decay and remained viable in room air long enough to represent an airborne infection risk.

Ultrasonic-resonator-combined apparatus for purifying nuclear aerosol particles

Energy Technology Data Exchange (ETDEWEB)

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

2017-12-15

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

Direct quantification of airborne nanoparticles composition by TXRF after collection on filters

Energy Technology Data Exchange (ETDEWEB)

Motellier, S; Lhaute, K; Guiot, A; Golanski, L; Tardif, F [CEA Grenoble, DRT, LITEN, DTNM, Laboratory of Nanochemistry and Nanosafety, 17 Avenue des Martyrs, Cedex 9, F-38054 Grenoble (France); Geoffroy, C, E-mail: sylvie.motellier@cea.fr [Elexience, 9 rue des petits ruisseaux, BP 61, 91371 Verrieres-le-Buisson Cedex (France)

2011-07-06

Direct TXRF analysis of nanoparticles deposited on filters was evaluated. Standard filters spiked with known amounts of NP were produced using an atomizer which generates an aerosol from a NP containing-liquid suspension. Polycarbonate filters provided the highest fluorescence signals and black polycarbonate filters containing chromium were further selected, Cr being used as internal standard for elemental quantification of the filter contaminants. Calibration curves were established for various NP (TiO{sub 2}, ZnO, CeO{sub 2}, Al{sub 2}O{sub 3}). Good linearity was observed. Low limits of detection were in the tens to the hundreds of ngs per filter, the method being less adapted to Al{sub 2}O{sub 3} due to the poor TXRF sensitivity for light elements. The analysis of MW-CNTs was attempted by quantification of their metal (Fe) catalyst impurities. Problems like CNT dispersion in liquids, quantification of the deposited quantity and high Fe-background contamination.

An assessment of cellulose filters as a standardized material for measuring litter breakdown in headwater streams

Science.gov (United States)

The decay rate of cellulose filters and associated chemical and biological characteristics were compared to those of white oak (Quercus alba) leaves to determine if cellulose filters could be a suitable standardized material for measuring deciduous leaf breakdown in headwater str...

Impact of fog processing on water soluble organic aerosols.

Science.gov (United States)

Tripathi, S. N.; Chakraborty, A.; Gupta, T.

2017-12-01

Fog is a natural meteorological phenomenon that occurs all around the world, and contains a substantial quantity of liquid water. Fog is generally seen as a natural cleansing agent but can also form secondary organic aerosols (SOA) via aqueous processing of ambient organics. Few field studies have reported elevated O/C ratio and SOA mass during or after fog events. However, mechanism behind aqueous SOA formation and its contribution to total organic aerosols (OA) still remains unclear. In this study we have tried to explore the impact of fog/aqueous processing on the characteristics of water soluble organic aerosols (WSOC), which to our knowledge has not been studied before. To assess this, both online (using HR-ToF-AMS) and offline (using a medium volume PM2.5 sampler and quartz filter) aerosol sampling were carried out at Kanpur, India from 15 December 2014 - 10 February 2015. Further, offline analysis of the aqueous extracts of the collected filters were carried out by AMS to characterize the water soluble OA (WSOA). Several (17) fog events occurred during the campaign and high concentrations of OA (151 ± 68 µg/m3) and WSOA (47 ± 19 µg/m3) were observed. WSOA/OA ratios were similar during fog (0.36 ± 0.14) and nofog (0.34 ± 0.15) periods. WSOA concentrations were also similar (slightly higher) during foggy (49 ± 18 µg/m3) and non-foggy periods (46 ± 20 µg/m3), in spite of fog scavenging. However, WSOA was more oxidized during foggy period (average O/C = 0.81) than non foggy periods (average O/C = 0.70). Like WSOA, OA was also more oxidized during foggy periods (average O/C = 0.64) than non foggy periods (average O/C = 0.53). During fog, WSOA to WIOA (water insoluble OA) ratios were higher (0.65 ± 0.16) compared to non foggy periods (0.56 ± 0.15). These observations clearly showed that WSOA become more dominant and processed during fog events, possibly due to the presence of fog droplets. This study highlights that fog processing of soluble organics

Online high sensitivity measurement system for transuranic aerosols

International Nuclear Information System (INIS)

Kordas, J.F.; Phelps, P.L.

1976-01-01

A measurement system for transuranic aerosols has been designed that will be able to withstand the corrosive nature of stack effluents and yet have extremely high sensitivity. It will be capable of measuring 1 maximum permissible concentration (MPC) of plutonium or americium in 30 minutes with a fractional standard deviation of less than 0.33. Background resulting from 218 Po is eliminated by alpha energy discrimination and a decay scheme analysis. A microprocessor controls all data acquisition, data reduction, and instrument calibration

Determination of trace elements in aerosols from the antarctic peninsula by neutron activation analysis

International Nuclear Information System (INIS)

Loureiro, A.L.M.

1989-01-01

In this work the neutron activation method was applied to carry out multielemental analysis in aerosols collected in the Brazilian Station 'Comandante Ferraz', located on King George Island, at the Antarctic Peninsula, during 1986 and 1987. The aerosols were collected on 0.45 μum Millipore-MF filter paper, type HA. The analytical method was based on the simultaneous irradiations of filters and synthetic standards in the IEA-R1 nuclear reactor under a thermal neutron flux of about 10 12 n cm -2 s -1 . The induced radioactivity was measured in a gamma ray spectrometer after suitable cooling times. Samples were irradiated twice, with irradiation times varying from 5 minutes to 24 hours. The elements Na, Al, Cl, K, Ca, Sc, V, Mn, Fe, Zn, Br, Sb, La, Au and Th were determined with concentration levels from ng/m 3 to pg/m 3 [pt

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

Infection of phytoplankton by aerosolized marine viruses

Science.gov (United States)

Sharoni, Shlomit; Trainic, Miri; Schatz, Daniella; Lehahn, Yoav; Flores, Michel J.; Bidle, Kay D.; Ben-Dor, Shifra; Rudich, Yinon; Vardi, Assaf

2015-01-01

Marine viruses constitute a major ecological and evolutionary driving force in the marine ecosystems. However, their dispersal mechanisms remain underexplored. Here we follow the dynamics of Emiliania huxleyi viruses (EhV) that infect the ubiquitous, bloom-forming phytoplankton E. huxleyi and show that EhV are emitted to the atmosphere as primary marine aerosols. Using a laboratory-based setup, we showed that the dynamic of EhV aerial emission is strongly coupled to the host–virus dynamic in the culture media. In addition, we recovered EhV DNA from atmospheric samples collected over an E. huxleyi bloom in the North Atlantic, providing evidence for aerosolization of marine viruses in their natural environment. Decay rate analysis in the laboratory revealed that aerosolized viruses can remain infective under meteorological conditions prevailing during E. huxleyi blooms in the ocean, allowing potential dispersal and infectivity over hundreds of kilometers. Based on the combined laboratory and in situ findings, we propose that atmospheric transport of EhV is an effective transmission mechanism for spreading viral infection over large areas in the ocean. This transmission mechanism may also have an important ecological impact on the large-scale host–virus “arms race” during bloom succession and consequently the turnover of carbon in the ocean. PMID:25964340

Filtered thermal neutron captured cross sections measurements and decay heat calculations

International Nuclear Information System (INIS)

Pham Ngoc Son; Vuong Huu Tan

2015-01-01

Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (R ed ) of 420 and neutron flux (Φ th ) of 1.6*10 6 n/cm 2 .s. This thermal neutron beam has been applied for measurements of capture cross sections for nuclide of 51 V, by the activation method relative to the standard reaction 197 Au(n,γ) 198 Au. In addition to the activities of neutron capture cross sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235 U are introduced in this report. (author)

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.

Characterization of biomass burning aerosols from forest fire in Indonesia

Science.gov (United States)

Fujii, Y.; Iriana, W.; Okumura, M.; Lestari, P.; Tohno, S.; Akira, M.; Okuda, T.

2012-12-01

Biomass burning (forest fire, wild fire) is a major source of pollutants, generating an estimate of 104 Tg per year of aerosol particles worldwide. These particles have adverse human health effects and can affect the radiation budget and climate directly and indirectly. Eighty percent of biomass burning aerosols are generated in the tropics and about thirty percent of them originate in the tropical regions of Asia (Andreae, 1991). Several recent studies have reported on the organic compositions of biomass burning aerosols in the tropical regions of South America and Africa, however, there is little data about forest fire aerosols in the tropical regions of Asia. It is important to characterize biomass burning aerosols in the tropical regions of Asia because the aerosol properties vary between fires depending on type and moisture of wood, combustion phase, wind conditions, and several other variables (Reid et al., 2005). We have characterized PM2.5 fractions of biomass burning aerosols emitted from forest fire in Indonesia. During the dry season in 2012, PM2.5 aerosols from several forest fires occurring in Riau, Sumatra, Indonesia were collected on quartz and teflon filters with two mini-volume samplers. Background aerosols in forest were sampled during transition period of rainy season to dry season (baseline period). Samples were analyzed with several analytical instruments. The carbonaceous content (organic and elemental carbon, OC and EC) of the aerosols was analyzed by a thermal optical reflectance technique using IMPROVE protocol. The metal, inorganic ion and organic components of the aerosols were analyzed by X-ray Fluorescence (XRF), ion chromatography and gas chromatography-mass spectrometry, respectively. There was a great difference of chemical composition between forest fire and non-forest fire samples. Smoke aerosols for forest fires events were composed of ~ 45 % OC and ~ 2.5 % EC. On the other hand, background aerosols for baseline periods were

Determination of water vapor and aerosol densities in the tropospheric atmosphere from nitrogen and water vapor raman signals

CERN Document Server

Kim, D H; Lee, J M; Yeon, K H; Choi, S C

1998-01-01

A Raman lidar system has been developed for the measurement of the water-vapor mixing ratio and the aerosol backscatter and extinction coefficients. To suppress the elastic scattering from the XeCl excimer laser, an acetone edge filter and narrow-band interference filters are used. By using independently calculated backscatter and extinction coefficients, we calculate the lidar ratios (extinction coefficient divided by the backscatter coefficient). The obtained ratios between 30 and 50 sr explain the special characteristics of the aerosol existing in the atmosphere. These ratios are also used as important parameters in the lidar inversion program. We have also obtained the water-vapor mixing ratio and find that big differences exist between the ratios inside the boundary layer and those of other regions.

Filter Measurement System for Nuclear Material Storage Canisters. End of Year Report FY 2013

Energy Technology Data Exchange (ETDEWEB)

Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reeves, Kirk P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-02-03

A test system has been developed at Los Alamos National Laboratory to measure the aerosol collection efficiency of filters in the lids of storage canisters for special nuclear materials. Two FTS (filter test system) devices have been constructed; one will be used in the LANL TA-55 facility with lids from canisters that have stored nuclear material. The other FTS device will be used in TA-3 at the Radiation Protection Division’s Aerosol Engineering Facility. The TA-3 system will have an expanded analytical capability, compared to the TA-55 system that will be used for operational performance testing. The LANL FTS is intended to be automatic in operation, with independent instrument checks for each system component. The FTS has been described in a complete P&ID (piping and instrumentation diagram) sketch, included in this report. The TA-3 FTS system is currently in a proof-of-concept status, and TA-55 FTS is a production-quality prototype. The LANL specification for (Hagan and SAVY) storage canisters requires the filter shall “capture greater than 99.97% of 0.45-micron mean diameter dioctyl phthalate (DOP) aerosol at the rated flow with a DOP concentration of 65±15 micrograms per liter”. The percent penetration (PEN%) and pressure drop (DP) of fifteen (15) Hagan canister lids were measured by NFT Inc. (Golden, CO) over a period of time, starting in the year 2002. The Los Alamos FTS measured these quantities on June 21, 2013 and on Oct. 30, 2013. The LANL(6-21-2013) results did not statistically match the NFT Inc. data, and the LANL FTS system was re-evaluated, and the aerosol generator was replaced and the air flow measurement method was corrected. The subsequent LANL(10-30-2013) tests indicate that the PEN% results are statistically identical to the NFT Inc. results. The LANL(10-30-2013) pressure drop measurements are closer to the NFT Inc. data, but future work will be investigated. An operating procedure for the FTS (filter test system) was written, and

Determination of the environmental effect for the sea salt aerosols corrosion (2)

International Nuclear Information System (INIS)

Nakayasu, Fumio; Umehara, Toshihiro; Kato, Akitoshi; Taniguchi, Akihide

2008-01-01

Present all nuclear power plants in Fukui prefecture are located at the bay side of Japan Sea coast. New facilities may be planed to be at ocean side. The sea salt corrosion at the ocean side should be larger than it at the bay side. We have the salt damage experimental yard at Awara sea coast and at Fukui city (about 15km from coast) for the corrosion comparison study between Japan Sea coast and inland. We confirm the amounts of sea salt aerosol vary among the season and year. The weight loss of specimen inside of shelter without filter is higher than both of sheltered with filter and inland specimen. The weight loss of specimen inside of shelter with filter is almost same as it of inland specimen. We confirmed the filter which we used is sufficient capability to prevent corrosion. We confirmed the corrosion rate of both opened specimen and sheltered specimen without filter increased after some periods. (author)

Study of the attachment between the decay products of 220Rn and monodisperse aerosols

International Nuclear Information System (INIS)

Kruger, J.

1974-10-01

Attachment can be described in terms of one of two theories, viz. the diffusion theory or the kinetic theory. The diffusion theory is based on the transport of radioactive atoms by means of the process of diffusion. An attachment proportional to the radius R of the aerosol particles for the size range used in these experiments, is predicted by this theory. The kinetic theory is based on intermolecular collisions as described by the kinetic theory of gasses. This theory predicts an attachment that is proportional to R 2 . Both these relationships have been established by other researchers. However, the author believes that they have not taken several important parameters into consideration in their experiments, several such parameters were also not properly controlled in their experiments. In the present investigation the attachment flux for the attachment of thorium B atoms (of an approximate concentration of 4x10 3 atoms/cm 3 ) to monodisperes polystyrene aerosols (of a radius from 0,5 to 2,5 μm) in the concentration range 1-30 particles/cm 3 , was directly measured. Steps were taken to prevent the formation of radiolytic nuclei, and all the relevant parameters were measured during the experiments. The attachment between the radioactive atoms and the aerosols was found to be directly proportional to the particle concentration N, as well as to R 2 . The sticking probability of atoms to a particle was found to be of the order of 0,1. The results show that the attachment was found; this was attributed to the attachment of radioactive atoms to agglomerate vapour molecules

The Pasadena Aerosol Characterization Observatory (PACO: chemical and physical analysis of the Western Los Angeles basin aerosol

Directory of Open Access Journals (Sweden)

S. P. Hersey

2011-08-01

in accumulation mode aerosol, while afternoon SOA production coincides with the appearance of a distinct fine mode dominated by organics. Particulate NH₄NO₃ and (NH₄₂SO₄ appear to be NH₃-limited in regimes I and II, but a significant excess of particulate NH₄⁺ in the hot, dry regime III suggests less SO₄²⁻ and the presence of either organic amines or NH₄⁺-associated organic acids. C-ToF-AMS data were analyzed by Positive Matrix Factorization (PMF, which resolved three factors, corresponding to a hydrocarbon-like OA (HOA, semivolatile OOA (SV-OOA, and low-volatility OOA (LV-OOA. HOA appears to be a periodic plume source, while SV-OOA exhibits a strong diurnal pattern correlating with ozone. Peaks in SV-OOA concentration correspond to peaks in DMA number concentration and the appearance of a fine organic mode. LV-OOA appears to be an aged accumulation mode constituent that may be associated with aqueous-phase processing, correlating strongly with sulfate and representing the dominant background organic component. Periods characterized by high SV-OOA and LV-OOA were analyzed by filter analysis, revealing a complex mixture of species during periods dominated by SV-OOA and LV-OOA, with LV-OOA periods characterized by shorter-chain dicarboxylic acids (higher O:C ratio, as well as appreciable amounts of nitrate- and sulfate-substituted organics. Phthalic acid was ubiquitous in filter samples, suggesting that PAH photochemistry may be an important SOA pathway in Los Angeles. Aerosol composition was related to water uptake characteristics, and it is concluded that hygroscopicity is largely controlled by organic mass fraction (OMF. The hygroscopicity parameter κ averaged 0.31 ± 0.08, approaching 0.5 at low OMF and 0.1 at high OMF, with increasing OMF suppressing hygroscopic growth and increasing critical dry diameter for CCN activation

In situ measurement of the efficiency of filtration installations in the nuclear industry by the soda-fluorescein (uranin) aerosol method: AFNOR standard NFX 44.011

International Nuclear Information System (INIS)

Dupoux, J.

1981-01-01

The in situ measurement of the efficiency of filtering installations in the French nuclear industry using the soda-fluorescein (uraniun) aerosol method is presented. A brief description and the interest of the method are discussed. Its use for the location of defects in filter elements and for in situ control of casing with tandem HEPA filter stages is described

Formation of high-molecular-weight compounds via the heterogeneous reactions of gaseous C8-C10 n-aldehydes in the presence of atmospheric aerosol components

Science.gov (United States)

Han, Yuemei; Kawamura, Kimitaka; Chen, Qingcai; Mochida, Michihiro

2016-02-01

A laboratory study on the heterogeneous reactions of straight-chain aldehydes was performed by exposing n-octanal, nonanal, and decanal vapors to ambient aerosol particles. The aerosol and blank filters were extracted using methanol. The extracts were nebulized and the resulting compositions were examined using a high-resolution time-of-flight aerosol mass spectrometer. The mass spectral analysis showed that the exposures of the aldehydes to aerosol samples increased the peak intensities in the high mass range. The peaks in the mass spectra of the aerosol samples after exposure to different aldehydes were characterized by a homologous series of peak shifts due to the addition of multiple CH2 units. This result is explained by the formation of high-molecular-weight (HMW) compounds that contain single or multiple aldehyde moieties. The HMW fragment peaks for the blank filters exposed to n-aldehydes were relatively weak, indicating an important contribution from the ambient aerosol components to the formation of the HMW compounds. Among the factors affecting the overall interaction of aldehydes with atmospheric aerosol components, gas phase diffusion possibly limited the reactions under the studied conditions; therefore, their occurrence to a similar degree in the atmosphere is not ruled out, at least for the reactions involving n-nonanal and decanal. The major formation pathways for the observed HMW products may be the self-reactions of n-aldehydes mediated by atmospheric aerosol components and the reactions of n-aldehydes with organic aerosol components. The observed formation of HMW compounds encourages further investigations into their effects on the aerosol properties as well as the organic aerosol mass in the atmosphere.

Operating experience of RAPSODIE and PHENIX relating to sodium aerosols and vapours

Energy Technology Data Exchange (ETDEWEB)

Delisle, J P; Reboul, M; Elie, X [DRNR/STRS - Centre de Cadarache, Saint-Paul-lez-Durance (France)

1977-01-01

The main difficulties resulting from sodium aerosols and vapours in the cover gas which have been encountered for 10 years in RAPSODIE and for 3 years in PHENIX are reviewed: condensation of sodium in annular spaces; plugging in primary gas pipes; plugging of filters and vapour traps. All those problems were easily overcome. (author)

Aerosol Scrubbing Performance Test for Self-Priming Scrubbing Nozzle Submerged in Water Pool

Energy Technology Data Exchange (ETDEWEB)

Lee, Doo Yong; Jung, Woo Young; Lee, Hyun Chul; Lee, Jong Chan; Kim, Gyu Tae; Song, Yong Jae [FNC Technology Co., Yongin (Korea, Republic of)

2016-10-15

A scrubbing nozzle is one of the key components for a wet scrubber process based Containment Filtered Venting System (CFVS). As a part of a development of Korean CFVS, a self-priming scrubbing nozzle shown in Fig. 1 has been developed based on the well-known venturi scrubber concept. The thermal-hydraulic performances such as the pressure drop across the nozzle, water suction behavior and droplet generation inside throat have been tested in the non-submerged condition as well as submerged condition. The self-priming scrubbing nozzle used for the wet scrubber based CFVS has been developed, which is submerged in the water pool. When there is gas flow at the inlet of the nozzle, the pool water is passively sucked from the water suction slit. The fine droplets generated inside the throat capture the aerosol particles and is discharged into the water pool. In the water pool, the pool scrubbing happens. The aerosol scrubbing performance tests for the developed self-priming scrubbing nozzle has been conducted under the operational conditions such as different aerosol sizes, different carrier gas steam fractions, different, different pool water level and nozzle inlet pressure. The major findings are as follows. (1) Aerosol scrubbing efficiency increases with the increase of the aerosol size. (2) Aerosol scrubbing efficiency increases with the increase of the carrier gas steam fraction. (3) Aerosol scrubbing.

Aerosol Scrubbing Performance Test for Self-Priming Scrubbing Nozzle Submerged in Water Pool

International Nuclear Information System (INIS)

Lee, Doo Yong; Jung, Woo Young; Lee, Hyun Chul; Lee, Jong Chan; Kim, Gyu Tae; Song, Yong Jae

2016-01-01

A scrubbing nozzle is one of the key components for a wet scrubber process based Containment Filtered Venting System (CFVS). As a part of a development of Korean CFVS, a self-priming scrubbing nozzle shown in Fig. 1 has been developed based on the well-known venturi scrubber concept. The thermal-hydraulic performances such as the pressure drop across the nozzle, water suction behavior and droplet generation inside throat have been tested in the non-submerged condition as well as submerged condition. The self-priming scrubbing nozzle used for the wet scrubber based CFVS has been developed, which is submerged in the water pool. When there is gas flow at the inlet of the nozzle, the pool water is passively sucked from the water suction slit. The fine droplets generated inside the throat capture the aerosol particles and is discharged into the water pool. In the water pool, the pool scrubbing happens. The aerosol scrubbing performance tests for the developed self-priming scrubbing nozzle has been conducted under the operational conditions such as different aerosol sizes, different carrier gas steam fractions, different, different pool water level and nozzle inlet pressure. The major findings are as follows. (1) Aerosol scrubbing efficiency increases with the increase of the aerosol size. (2) Aerosol scrubbing efficiency increases with the increase of the carrier gas steam fraction. (3) Aerosol scrubbing

The application of an improved gas and aerosol collector for ambient air pollutants in China

Science.gov (United States)

Dong, Huabin; Zeng, Limin; Zhang, Yuanhang; Hu, Min; Wu, Yusheng

2016-04-01

An improved Gas and Aerosol Collector (GAC) equipped with a newly designed aerosol collector and a set of dull-polished wet annular denuder (WAD) was developed by Peking University based on a Steam Jet Aerosol Collector (SJAC) sampler. Combined with Ion Chromatography (IC) the new sampler performed well in laboratory tests with high collection efficiencies for SO2 (above 98 %) and particulate sulfate (as high as 99.5 %). An inter-comparison between the GAC-IC system and the filter-pack method was performed and the results indicated that the GAC-IC system could supply reliable particulate sulfate, nitrate, chloride, and ammonium data in field measurement with a much wider range of ambient concentrations. From 2008 to 2015, dozens of big field campaigns (rural and coastal sites) were executed in different parts of China, the GAC-IC system took the chance having its field measurement performance checked repeatedly and provided high quality data in ambient conditions either under high loadings of pollutants or background area. Its measurements were highly correlated with data by other commercial instruments such as the SO2 analyzer, the HONO analyzer, a filter sampler, Aerosol Mass Spectrometer (AMS), etc. over a wide range of concentrations and proved particularly useful in future intensive campaigns or long-term monitoring stations to study various environmental issues such as secondary aerosol and haze formation. During these years of applications of GAC-IC in those field campaigns, we found some problems of several instruments running under field environment and some interesting results could also be drew from the large amount of data measured in near 20 provinces of China. Detail results will be demonstrated on the poster afterwards.

A Laboratory Investigation of Aerosol and Extinction Characteristics for SALTY DOG, NWC 29 and NWC 78 Pyrotechnics

Science.gov (United States)

1980-10-01

The artificial fogs are produced by 1’SALTY DOC,14 and phosphorus pentoxide smokeS~in Calspan’s 590 cubic meter chamber at controlled relative...the chamber experiments, an isokinetic sampling inlet was employed for minimizing aerosol losses during sampling. Instrumentation used to monitor...with a 1 cfm critical orifice and vacuum pump. Additionally, a flow meter , placed behind the filter, was monitored to assure that filter loading did

Development of Methodologies from Determination of Organic Components from Atmospheric Aerosol

International Nuclear Information System (INIS)

Pindado, O.; Perez, R.; Garcia, R.; Barrado, A. I.; Sevillano, M. L.; Gonzalez, D.

2006-01-01

It is presented method for the organic compound determination, such as n-alkanes, PAH's, alcohols and fatty acids that are comprised the particulate matter of aerosol. The procedure is based on sampling the particulate matter over quartz fibre filters that will be extracted by means of the Soxhiet technique, and later they will be divided by means of silicagel column. PAH's is analyzed by means of HPLCm whereas the rest is analyzed by GC-MS and for it, acids and alcohol must be previously derivatized with BSTFA.12 samples took shelter of fractions PMIO and PM2.5 of the aerosol of country side like application of the method. (Author) 60 refs

Filtered thermal neutron captured cross-sections measurements and decay heat calculations

International Nuclear Information System (INIS)

Son, Pham Ngoc; Tan, Vuong Huu

2014-01-01

Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (R cd ) of 420 and neutron flux (Φ th ) of 1.6x10 6 n/cm 2 .s. This thermal neutron beam has been applied for measurements of capture cross-sections for nuclide of 51 V, 55 Mn, 180 Hf and 186 W by the activation method relative to the standard reaction 197 Au(n,g) 198 Au. In addition to the activities of neutron capture cross-sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235 U, 238 U, 239 Pu and 232 Th are introduced in this report. (author)

An Improved Cambridge Filter Pad Extraction Methodology to Obtain More Accurate Water and “Tar” Values: In Situ Cambridge Filter Pad Extraction Methodology

OpenAIRE

Ghosh David; Jeannet Cyril

2014-01-01

Previous investigations by others and internal investigations at Philip Morris International (PMI) have shown that the standard trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387 (Cigarettes -- Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine), is not suitable for high-water content aerosols. Errors occur because of water losses during the opening of the Cambridge filter p...

Characterization of fine aerosol and its inorganic components at two rural locations in New York State.

Science.gov (United States)

Sunder Raman, Ramya; Hopke, Philip K; Holsen, Thomas M

2008-09-01

Samples of PM(2.5) were collected to measure the concentrations of its chemical constituents at two rural locations, Potsdam and Stockton, NY from November 2002 to August 2005. These samples were collected on multiple filters at both sites, every third day for a 24-h interval with a speciation network sampler. The Teflo filters were analyzed for PM(2.5) mass by gravimetry, and elemental composition by X-ray fluorescence (XRF). Nylasorb filters and Teflo filters were leached with water and analyzed for anions and cations, respectively, by ion chromatography (IC). Fine particulate matter (PM(2.5)) mass and its inorganic component measurements were statistically characterized, and the temporal behavior of these species were assessed. Over the entire study period, PM(2.5) mass concentrations were lower at Potsdam (8.35 microg/m(3)) than at Stockton (10.24 microg/m(3)). At both locations, organic matter (OM) was the highest contributor to mass. Sulfate was the second highest contributor to mass at 27.0% at Potsdam, and 28.7% at Stockton. Nitrate contributions to mass of 8.9 and 9.5% at Potsdam and Stockton, respectively, were the third highest. At both locations, fine PM mass exhibited an annual cycle with a pronounced summer peak and indications of another peak during the winter, consistent with an overall increase in the rate of secondary aerosol formation during the summer, and increased partitioning of ammonium nitrate to the particle phase and condensation of other semi-volatiles during the winter, respectively. An ion-balance analysis indicated that at both locations, during the summers as well as in the winters, the aerosol was acidic. Lognormal frequency distribution fits to the measured mass concentrations on a seasonal basis indicated the overall increase in particle phase secondary aerosol (sulfate and SOA) concentrations during the summers compared to the winters at both locations.

Hygroscopic growth of water soluble organic carbon isolated from atmospheric aerosol collected at US national parks and Storm Peak Laboratory

Science.gov (United States)

Taylor, Nathan F.; Collins, Don R.; Lowenthal, Douglas H.; McCubbin, Ian B.; Gannet Hallar, A.; Samburova, Vera; Zielinska, Barbara; Kumar, Naresh; Mazzoleni, Lynn R.

2017-02-01

Due to the atmospheric abundance and chemical complexity of water soluble organic carbon (WSOC), its contribution to the hydration behavior of atmospheric aerosol is both significant and difficult to assess. For the present study, the hygroscopicity and CCN activity of isolated atmospheric WSOC particulate matter was measured without the compounding effects of common, soluble inorganic aerosol constituents. WSOC was extracted with high purity water from daily high-volume PM2.5 filter samples and separated from water soluble inorganic constituents using solid-phase extraction. The WSOC filter extracts were concentrated and combined to provide sufficient mass for continuous generation of the WSOC-only aerosol over the combined measurement time of the tandem differential mobility analyzer and coupled scanning mobility particle sizer-CCN counter used for the analysis. Aerosol samples were taken at Great Smoky Mountains National Park during the summer of 2006 and fall-winter of 2007-2008; Mount Rainier National Park during the summer of 2009; Storm Peak Laboratory (SPL) near Steamboat Springs, Colorado, during the summer of 2010; and Acadia National Park during the summer of 2011. Across all sampling locations and seasons, the hygroscopic growth of WSOC samples at 90 % RH, expressed in terms of the hygroscopicity parameter, κ, ranged from 0.05 to 0.15. Comparisons between the hygroscopicity of WSOC and that of samples containing all soluble materials extracted from the filters implied a significant modification of the hydration behavior of inorganic components, including decreased hysteresis separating efflorescence and deliquescence and enhanced water uptake between 30 and 70 % RH.

A low pressure filter system for new containment concepts

Energy Technology Data Exchange (ETDEWEB)

Dillmann, H.G.; Pasler, H. [Kernforschungszentrum Karlsruhe GmbH Laboratorium fuer Isotopentechnik, Karlsruhe (Germany)

1995-02-01

It is demonstrated that after severe accidents the decay heat can be removed in a passive mode in a convective flow, i.e. without needing a fan. The filter components with sufficiently low pressure drop values which are required for this purpose will be described and the results indicated.

Is Distant Pollution Contaminating Local Air? Analyzing the Origins of Atmospheric Aerosols

Directory of Open Access Journals (Sweden)

David Geng

2012-01-01

Full Text Available Understanding the origin of aerosols in the atmosphere is important because of visual pollution, climate impacts, and deleterious health effects due to the inhalation of fine particles. This research analyzed aerosols characterized by their chloride, sulfate, and nitrate content as a function of size over a 3-month period. Due to wind patterns over coal-burning power plants, a higher concentration of local sulfate pollution was expected. Aerosols were harvested on the Purdue University campus using a high-volume air sampler with glass fiber filters and a five-stage impactor that separates the aerosols into five sizes. The filters were extracted in water to dissolve anions and the solution was analyzed using high-pressure liquid ion chromatography. Only trace amounts of chloride with no distinct patterns in size were detected. In total, nitrate content ranged from 0.12 to 2.10 μg/m3 and sulfate content ranged from 0.44 to 6.45 μg/m3 over a 3-month period. As for fine particles, a higher concentration of sulfate was observed. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT model determines air mass origin, and in this study, higher total sulfate content was observed when the air mass moved out of the southwest, and higher total nitrate content was observed when the air mass originated from the southeast. The author concluded that small particles resulted in sulfate from sulfur dioxide, typically from gas to particle conversion. High sulfur dioxide levels are directly correlated with coal-burning power plant density. Small particulate sulfate found in West Lafayette, Indiana, was determined to originate primarily from power plants in southwest Indiana. Though the results do show a significant amount of potentially harmful aerosols in West Lafayette, there is still further research to be done concerning isotopic composition of those particles in attempts to better explain the chemical pathways.

Complementary online aerosol mass spectrometry and offline FT-IR spectroscopy measurements: Prospects and challenges for the analysis of anthropogenic aerosol particle emissions

Science.gov (United States)

Faber, Peter; Drewnick, Frank; Bierl, Reinhard; Borrmann, Stephan

2017-10-01

The aerosol mass spectrometer (AMS) is well established in investigating highly time-resolved dynamics of submicron aerosol chemical composition including organic aerosol (OA). However, interpretation of mass spectra on molecular level is limited due to strong fragmentation of organic substances and potential reactions inside the AMS ion chamber. Results from complementary filter-based FT-IR absorption measurements were used to explain features in high-resolution AMS mass spectra of different types of OA (e.g. cooking OA, cigarette smoking OA, wood burning OA). Using this approach some AMS fragment ions were validated in this study as appropriate and rather specific markers for a certain class of organic compounds for all particle types under investigation. These markers can therefore be used to get deeper insights in the chemical composition of OA based on AMS mass spectra in upcoming studies. However, the specificity of other fragment ions such as C2H4O2+ (m/z 60.02114) remains ambiguous. In such cases, complementary FT-IR measurements allow the interpretation of highly time-resolved AMS mass spectra at the level of molecular functional groups. Furthermore, this study discusses the challenges in reducing inorganic interferences (e.g. from water and ammonium salts) in FT-IR spectra of atmospheric aerosols to decrease spectral uncertainties for better comparisons and, thus, to get more robust results.

Workplace Exposure to Titanium Dioxide Nanopowder Released from a Bag Filter System

Directory of Open Access Journals (Sweden)

Jun Ho Ji

2015-01-01

Full Text Available Many researchers who use laboratory-scale synthesis systems to manufacture nanomaterials could be easily exposed to airborne nanomaterials during the research and development stage. This study used various real-time aerosol detectors to investigate the presence of nanoaerosols in a laboratory used to manufacture titanium dioxide (TiO2. The TiO2 nanopowders were produced via flame synthesis and collected by a bag filter system for subsequent harvesting. Highly concentrated nanopowders were released from the outlet of the bag filter system into the laboratory. The fractional particle collection efficiency of the bag filter system was only 20% at particle diameter of 100 nm, which is much lower than the performance of a high-efficiency particulate air (HEPA filter. Furthermore, the laboratory hood system was inadequate to fully exhaust the air discharged from the bag filter system. Unbalanced air flow rates between bag filter and laboratory hood systems could result in high exposure to nanopowder in laboratory settings. Finally, we simulated behavior of nanopowders released in the laboratory using computational fluid dynamics (CFD.

The diffusion and deposition of the gaseous and solid alpha radionuclides/aerosols in air

International Nuclear Information System (INIS)

Danis, A.; Ciubotariu, M.; Oncescu, M.; Mocsy, I.

1999-01-01

The diffusion and deposition of gaseous and solids alpha radionuclides and aerosols in air are processes which implicate low element amounts and therefore their studies require the using of very accurate and sensitive analysis methods. The alpha track method meets these requirements. The used alpha radionuclides were: Rn-222, as gaseous radionuclide and its solid descendants genetically related as solid radionuclides and the descendants attached to different particles from air as alpha aerosols. All these radionuclides were obtained from a calibrated Ra-226 source. The source was included into an air tight device with a well known volume and used after 40 days when the Ra-226 and its alpha descendants were under radioactive equilibrium. The relative amount and activity of each decay product, at any duration, for any initial mass of Ra-226 parent radionuclide, were calculated using a programme for computation of the U-238 radioactive series gamma accumulation, UURASE, adapted for alpha accumulation as ALFAURASE programme. The radon, Rn-222, as well as the solid alpha radionuclides and aerosols were measured using a new alpha monitoring device with or without paper filter for solid radionuclides and aerosols stopping. The track detectors of CR-39 type were incorporated with these monitoring devices. In order to calibrate the CR-39 detectors, a radon intercomparison programme was established with the participation of the SSNTD group from the Institute of Nuclear Research ATOMKI, Debrecen, Hungary, Institute of Public Health, Cluj-Napoca and SSNTD research group from IFIN-HH. We have used for radon calibration a special experimental device and a Ra-226 source. Using an air tight diffusion and deposition device, coupled with the source device, the concentration of radon and solid alpha radionuclides and aerosols were determined using the alpha track method. The alpha monitoring devices were fixed vertically at different distances from the place of radon penetration into

ANALYSIS OF SECONDARY ORGANIC AEROSOL COMPOUNDS FROM THE PHOTOOXIDATION OF D-LIMONENE IN THE PRESENCE OF NO X AND THEIR DETECTION IN AMBIENT PM 2.5

Science.gov (United States)

Chemical analysis of secondary organic aerosol (SOA) from the photooxidation of a d-limonene/NOx/air mixture was carried out. SOA, generated in a smog chamber, was collected on Zefluor filters. To determine the structural characteristics of the compounds, the filter sample...

Evaporation of lead and lithium from molten Pb-17Li - transport of aerosols

International Nuclear Information System (INIS)

Feuerstein, H.; Graebner, H.; Oschinski, J.; Horn, S.; Bender, S.

1991-01-01

Evaporation of Pb and Li from molten Pb-17Li was investigated between 350 and 800deg C in vacuum, argon and helium covergas. Results were also obtained from other experimental facilities. Similarities were found to observations from sodium cooled reactors. The results show that Pb and Li evaporate independent on each other. The two elements show different behavior along the transport pathway. Deposits of the evaporated metals contained between 0.2 and 98 at% Li. As in the reactor RAPSODIE for sodium, evaporation rates for lithium were smaller in helium than in argon, however evaporation rates of lead were the same in both gases. No aerosol problems will exist with normal blanket operation. Under experimental conditions, aerosol concentrations were in the range of 10 -9 to 10 -6 g/m 3 . Aerosols can easily be trapped with sintered metal filters. (orig.)

Interactions of fission product vapours with aerosols

Energy Technology Data Exchange (ETDEWEB)

Benson, C G; Newland, M S [AEA Technology, Winfrith (United Kingdom)

1996-12-01

Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350{sup o}C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs.

Interactions of fission product vapours with aerosols

International Nuclear Information System (INIS)

Benson, C.G.; Newland, M.S.

1996-01-01

Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350 o C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs

Analysis of the implementation of a sand bed type filter for the venting of a nuclear power plant

International Nuclear Information System (INIS)

Cuevas V, D.; Sainz M, E.; Ortiz V, J.

2017-09-01

The filtered venting of the containment has been adopted in European countries to mitigate the consequences derived from the excess pressure of the containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter is placed in the path of the same, so various types of filters are used to trap the fission products. The containment venting filters currently installed use different filtering technologies that involve more than one medium. Those who use water as the first stage of filtration are called wet systems, are equipped with additional stages to eliminate water drops and emissions of fine aerosols, and may even be equipped with an element that contains certain means of absorption for the gaseous iodine species filtration. Other designs, based on deep bed filtration as the main retention stage, called dry filters; use metal fiber, ceramic or sand filtration media to trap aerosols. The present work evaluates the hydraulic characteristics of the sand bed type filter designed by EDF as a candidate to be installed in the containment of the BWR Mark II (primary containment type of the Laguna Verde nuclear power plant). The evaluation of the sand bed filter was performed using the OpenFOAM open source software package. Models of each zone of the filtering device were generated and by means of a series of parametric calculations of computational fluid mechanics, the relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow and pressure fields and velocity under different operating conditions. On the other hand, the validation of the sand bed filter model was made when comparing the results of experimental tests carried out in a sand column of the PITEAS program (1985-1986) against the simulation in OpenFOAM. The results obtained are very close to those obtained experimentally. (Author)

In Vitro Tests for Aerosol Deposition. V: Using Realistic Testing to Estimate Variations in Aerosol Properties at the Trachea.

Science.gov (United States)

Wei, Xiangyin; Hindle, Michael; Delvadia, Renishkumar R; Byron, Peter R

2017-10-01

The dose and aerodynamic particle size distribution (APSD) of drug aerosols' exiting models of the mouth and throat (MT) during a realistic inhalation profile (IP) may be estimated in vitro and designated Total Lung Dose, TLD in vitro , and APSD TLDin vitro , respectively. These aerosol characteristics likely define the drug's regional distribution in the lung. A general method was evaluated to enable the simultaneous determination of TLD in vitro and APSD TLDin vitro for budesonide aerosols' exiting small, medium and large VCU-MT models. Following calibration of the modified next generation pharmaceutical impactor (NGI) at 140 L/min, variations in aerosol dose and size exiting MT were determined from Budelin ® Novolizer ® across the IPs reported by Newman et al., who assessed drug deposition from this inhaler by scintigraphy. Values for TLD in vitro from the test inhaler determined by the general method were found to be statistically comparable to those using a filter capture method. Using new stage cutoffs determined by calibration of the modified NGI at 140 L/min, APSD TLDin vitro profiles and mass median aerodynamic diameters at the MT exit (MMAD TLDin vitro ) were determined as functions of MT geometric size across Newman's IPs. The range of mean values (n ≥ 5) for TLD in vitro and MMAD TLDin vitro for this inhaler extended from 6.2 to 103.0 μg (3.1%-51.5% of label claim) and from 1.7 to 3.6 μm, respectively. The method enables reliable determination of TLD in vitro and APSD TLDin vitro for aerosols likely to enter the trachea of test subjects in the clinic. By simulating realistic IPs and testing in different MT models, the effects of major variables on TLD in vitro and APSD TLDin vitro may be studied using the general method described in this study.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-09-15

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

The anthropogenic influence on carbonaceous aerosol in the European background

Energy Technology Data Exchange (ETDEWEB)

May, Barbara; Wagenbach, Dietmar; Hammer, Samuel (Institut fuer Umweltphysik, Univ. Heidelberg (Germany)). e-mail: barbara.may@iup.uni-heidelberg.de; Steier, Peter (VERA laboratory, Univ. of Vienna (Austria)); Puxbaum, Hans (Inst. for Chemical Technologies and Analytics, Vienna Univ. of Technology, Vienna (Austria)); Pio, Casimiro (CESAM and Dept. of Environment, Univ. of Aveiro (Portugal))

2009-07-01

To constrain the relatively uncertain anthropogenic impact on the organic aerosol load, radiocarbon analyses were performed on aerosol samples, collected year-round, at six non-urban sites including a maritime background and three remote mountain stations, lying on a west-east transect over Western Europe. From a crude three component model supported by TOC and levoglucosan filter data, the fossil fuel, biomass burning and biogenic TOC fraction are estimated, showing at all stations year-round, a relatively constant fossil fuel fraction of around (26 +- 6)%, a dominant biogenic contribution of on average (73 +- 7)% in summer and the continental as well as the maritime background TOC to be only about 50% biogenic. Assuming biomass burning as completely anthropogenic, the carbonaceous aerosol concentration at the mountain sites was found to have increased by a factor of up to (1.4 +- 0.2) in summer and up to (2.5 +- 1.0) in winter. This figure is significantly lower, however, than the respective TOC change since pre-industrial times seen in an Alpine ice core. Reconciling both observations would require an increase, since pre-industrial times, of the background biogenic aerosol load, which is estimated at a factor of 1.3-1.7.

The anthropogenic influence on carbonaceous aerosol in the European background

Energy Technology Data Exchange (ETDEWEB)

May, Barbara; Wagenbach, Dietmar; Hammer, Samuel (Inst. fuer Umweltphysik, Univ. Heidelberg (Germany)). e-mail: barbara.may@iup.uni-heidelberg.de; Steier, Peter (VERA laboratory, Univ. of Vienna (Austria)); Puxbaum, Hans (Inst. for Chemical Technologies and Analytics, Vienna Univ. of Technology (Austria)); Pio, Casimiro (CESAM and Dept. of Environment, Univ. of Aveiro (Portugal))

2008-07-01

To constrain the relatively uncertain anthropogenic impact on the organic aerosol load, radiocarbon analyses were performed on aerosol samples, collected year-round, at six non-urban sites including a maritime background and three remote mountain stations, lying on a west-east transect over Western Europe. From a crude three component model supported by TOC and levoglucosan filter data, the fossil fuel, biomass burning and biogenic TOC fraction are estimated, showing at all stations year-round, a relatively constant fossil fuel fraction of around (26 +- 6)% , a dominant biogenic contribution of on average (73 +- 7)% in summer and the continental as well as the maritime background TOC to be only about 50% biogenic. Assuming biomass burning as completely anthropogenic, the carbonaceous aerosol concentration at the mountain sites was found to have increased by a factor of up to (1.4 +- 0.2) in summer and up to (2.5 +- 1.0) in winter. This figure is significantly lower, however, than the respective TOC change since pre-industrial times seen in an Alpine ice core. Reconciling both observations would require an increase, since pre-industrial times, of the background biogenic aerosol load, which is estimated at a factor of 1.3-1.7

Source apportionment of carbonaceous aerosol in southern Sweden

Directory of Open Access Journals (Sweden)

J. Genberg

2011-11-01

Full Text Available A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM₁₀ were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (¹⁴C and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM₁₀ fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (80%, which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (32% and fossil fuel combustion (28% were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP MSC-W chemical transport model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 2.2 compared to the measurements.

Development and evaluation of a cleanable high efficiency steel filter

International Nuclear Information System (INIS)

Bergman, W.; Larsen, G.; Weber, F.; Wilson, P.; Lopez, R.; Valha, G.; Conner, J.; Garr, J.; Williams, K.; Biermann, A.; Wilson, K.; Moore, P.; Gellner, C.; Rapchun, D.; Simon, K.; Turley, J.; Frye, L.; Monroe, D.

1993-01-01

We have developed a high efficiency steel filter that can be cleaned in-situ by reverse air pulses. The filter consists of 64 pleated cylindrical filter elements packaged into a 6l0 x 6l0 x 292 mm aluminum frame and has 13.5 m 2 of filter area. The filter media consists of a sintered steel fiber mat using 2 μm diameter fibers. We conducted an optimization study for filter efficiency and pressure drop to determine the filter design parameters of pleat width, pleat depth, outside diameter of the cylinder, and the total number of cylinders. Several prototype cylinders were then built and evaluated in terms of filter cleaning by reverse air pulses. The results of these studies were used to build the high efficiency steel filter. We evaluated the prototype filter for efficiency and cleanability. The DOP filter certification test showed the filter has a passing efficiency of 99.99% but a failing pressure drop of 0.80 kPa at 1,700 m 3 /hr. Since we were not able to achieve a pressure drop less than 0.25 kPa, the steel filter does not meet all the criteria for a HEPA filter. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned by reverse air pulses. The next phase of the prototype evaluation consisted of installing the unit and support housing in the exhaust duct work of a uranium grit blaster for a field evaluation at the Y-12 Plant in Oak Ridge, TN. The grit blaster is used to clean the surface of uranium parts and generates a cloud of UO 2 aerosols. We used a 1,700 m 3 /hr slip stream from the 10,200 m 3 /hr exhaust system

Experiments on aerosol removal by high-pressure water spray

Energy Technology Data Exchange (ETDEWEB)

Corno, Ada del, E-mail: delcorno@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Morandi, Sonia, E-mail: morandi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Parozzi, Flavio, E-mail: parozzi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Araneo, Lucio, E-mail: lucio.araneo@polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy); CNR-IENI, via Cozzi 53, I-20125 Milano (Italy); Casella, Francesco, E-mail: francesco2.casella@mail.polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy)

2017-01-15

Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m{sup 3}. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m{sup 3}. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was

Experiments on aerosol removal by high-pressure water spray